Co-reporter:Jie Dou, Yafeng Li, Fengyan Xie, Tahsin J. Chow, Mingdeng Wei
Solar Energy 2017 Volume 155(Volume 155) pp:
Publication Date(Web):1 October 2017
DOI:10.1016/j.solener.2017.06.016
•The dyes especially suitable for Zn2SnO4 were investigated.•The PSP dyes exhibited a higher efficiency of 4.68% than that of N719 and D131.•The pre-calcination of Zn2SnO4 resulted in a 17% enhancement of efficiency.•The charge collection efficiency was enhanced greatly after the pre-calcination.Zinc stannate (ZTO) is a class of ternary oxides that are known for their stable properties and high electron mobility. Also, its chemical compositions and band structures are easy to be controlled, and which is thus ideal for applications in dye-sensitized solar cells (DSCs). However, the structures of most dyes are optimized for the widely used TiO2. Therefore, the efficient dyes that are especially suitable for ZTO are highly desired. In this study, the dyes containing phenylene-thiophenylene-phenylene bridge (PSP) were found to match well with the band structures of ZTO and could be used as efficient sensitizers for ZTO-based solar cells. Moreover, the pre-calcination temperatures have great influence on the band structures of ZTO. When ZTO nanoparticles were pre-sintered, although the adsorption amount of dyes was decreased, the charge collection efficiency was confirmed to be enhanced greatly. A cell sensitized by optimized PSP dyes exhibited a power conversion efficiency of 4.68%, which was much higher than that of widely used N719 and D131.
Co-reporter:Weifeng Zhang, Tongbin Lan, Tianli Ding, Nae-Lih Wu, Mingdeng Wei
Journal of Power Sources 2017 Volume 359(Volume 359) pp:
Publication Date(Web):15 August 2017
DOI:10.1016/j.jpowsour.2017.05.040
•A new strategy was proposed for preparing carbon coated TiO2 mesocrystals.•Anatase TiO2 mesocrystals with tunable architectures were successfully formed.•A highly reversible capacity up to 5000 cycles was achieved.Nanoporous anatase TiO2 mesocrystals with tunable architectures and crystalline phases were successfully fabricated in the presence of the butyl oleate and oleylamine. Especially, the introduced surfactants served as a carbon source, bring a uniform carbon layer (about 2–8 nm) for heightening the electronic conductivity. The carbon coated TiO2 mesocrystals assembled from crystalline tiny subunits have more space sites for sodium-ion storage. When the material was applied as an electrode material in rechargeable sodium-ion batteries, it exhibited a superior capacity of about 90 mA h g−1 at 20 C (1 C = 168 mA g−1) and a highly reversible capacity for 5000 cycles, which is the longest cycle life reported for sodium storage in TiO2 electrodes.Download high-res image (390KB)Download full-size image
Co-reporter:Wenqiang Chen, Weifeng Zhang, Lin Chen, Lingxing Zeng, Mingdeng Wei
Journal of Alloys and Compounds 2017 Volume 723(Volume 723) pp:
Publication Date(Web):5 November 2017
DOI:10.1016/j.jallcom.2017.06.153
•Cu2O nanorod arrays on Cu foam have been synthesized via a hydrothermal method.•This material was used as a binder-free anode material for lithium-ion battery.•This material exhibited excellent cycling performance with negligible capacity fading.In the present work, we have successfully fabricated three-dimensional Cu2O nanorod arrays on Cu foam by an efficient solvothermal approach followed by a post-annealing treatment with using PVP as a reducing agent. These materials were further investigated as binder- and conductive-agent-free anodes for lithium-ion batteries. It was found that the Cu2O nanorod arrays on Cu foam exhibited excellent cycle performance with negligible capacity fading, high reversible capacity, and superior rate capability compared with commercial Cu2O nanoparticles.Cu2O nanorod arrays on Cu foam exhibited excellent cycling stability with negligible capacity fading.Download high-res image (92KB)Download full-size image
Co-reporter:Tongbin Lan, Tao Wang, Weifeng Zhang, Nae-Lih Wu, Mingdeng Wei
Journal of Alloys and Compounds 2017 Volume 699(Volume 699) pp:
Publication Date(Web):30 March 2017
DOI:10.1016/j.jallcom.2016.12.337
•Rutile TiO2 mesocrystals composed of ultra-tiny rod-like subunits were successfully synthesized.•The sizes and morphologies of the subunits can be changed by a hydrothermal re-treatment process.•A capacity of 129.6 mA h g−1 for over 1000 cycles at 5 C can be achieved.•This material exhibited superior sodium storage property in terms of long-term cycling stability.A facile, low-temperature hydrothermal synthetic route was designed for fabricating rutile TiO2 mesocrystals composed of ultra-tiny, rod-like subunits. Mesocrystals with tunable sizes and morphologies of the subunits can be simultaneously achieved through a hydrothermal re-treatment process at different temperatures. A probable mechanism for the formation of the self-assembled giant rutile TiO2 mesocrystals of various sizes and morphologies is proposed based on the experimental results. The rutile TiO2 giant mesocrystals as-fabricated were also tested as anode materials for sodium-ion storage, and exhibited a capacity of 129.6 mA h g−1 with a capacity retention of 97% for over 1000 cycles at a charge–discharge rate as high as 5 C and enhanced rate capability up to 30 C (64.5 mA h g−1 at 30 C), effectually demonstrating superior sodium storage properties in terms of long-term cycling stability and rate capability.Rutile TiO2 mesocrystals with suitable sizes of subunits promote the electrode kinetic, manifesting superior sodium storage properties in terms of ascendant long-term cycling stability and good rate capability.Download high-res image (338KB)Download full-size image
Co-reporter:Lingxing Zeng;Xi Chen;Renpin Liu;Liangxu Lin;Cheng Zheng;Lihong Xu;Fenqiang Luo;Qingrong Qian;Qinghua Chen
Journal of Materials Chemistry A 2017 vol. 5(Issue 44) pp:22997-23005
Publication Date(Web):2017/11/14
DOI:10.1039/C7TA06884K
In the present work, we designed a dual-spatial carbon protection strategy for a Se reservoir, in which a Se/hierarchical porous carbon fiber (Se/HPCF) composite was homogeneously anchored on reduced graphene oxide (Se/HPCF–rGO). HPCF with high specific surface area and large pore volume was synthesized for the first time by using sodium lignosulfonate (LN) as a green porogen based on an electrospinning route. The Se/HPCF–rGO composite exhibits excellent electrochemical performance when employed as a cathode material for Li–Se batteries. For instance, a high reversible capacity of 616 mA h g−1 was maintained after 50 cycles at a rate of 0.2C. More importantly, the Se/HPCF–rGO composite delivered a high capacity of 208 mA h g−1 at a high rate of 10C even after 5000 cycles. The outstanding electrochemical performance can be attributed to the synergistic effect of the diverse structural features and fast reaction kinetics for lithium storage.
Co-reporter:Cheng Zheng;Congrong Chen;Lin Chen
Journal of Materials Chemistry A 2017 vol. 5(Issue 37) pp:19632-19638
Publication Date(Web):2017/09/26
DOI:10.1039/C7TA06286A
A tubular composite of MoSe2/CMK-5 was fabricated through a nanocasting route, in which ultra-thin two-dimensional MoSe2 nanosheets were encapsulated in ordered tubular mesoporous carbon CMK-5 with a massive internal surface area. As an anode for Li-ion intercalation, the CMK-5 matrix could not only provide sufficient space to buffer the volume change of MoSe2 during the charge–discharge process, but also increase the electrical conductivity and shorten the lithium-ion diffusion pathway. It was found that the MoSe2/CMK-5 composite exhibited an outstanding specific capacity of 788 mA h g−1 at a current density of 100 mA g−1 and excellent high rate performance. More importantly, a capacity of 451 mA h g−1 could be retained after 1000 cycles even at a current density as high as 2000 mA g−1, indicating that such a composite has long-term cycling stability.
Co-reporter:Xun Sun, Yafeng Li, Haijuan Mao, Jie Dou, Mingdeng Wei
Journal of Power Sources 2017 Volume 359(Volume 359) pp:
Publication Date(Web):15 August 2017
DOI:10.1016/j.jpowsour.2017.05.059
•Co-additives without TBP were first applied in the electrolyte of DSCs.•The synergetic effect of benzimidazole and 2-ethylimidazole has been researched.•By optimizing the ratio, an efficiency of 7.93% was got with a high Voc of 0.817 V.The co-additives of benzimidazole and 2-ethylimidazole in electrolyte have an obvious effect on the performance of dye-sensitized solar cells due to their good coordination ability of titanium dioxide, which could affect the energy levels and charge transfer process. Through a balance of the concentrations, the best efficiency of 7.93% with a high open-circuit voltage of 0.817 V is achieved for a cell fabricated with the electrolyte contains benzimidazole and 2-ehtylimidazole by a molar ratio of 9.5/0.5.
Co-reporter:Lingxing Zeng, Xiaoxia Huang, Xi Chen, Cheng Zheng, Qingrong Qian, Qinghua Chen, and Mingdeng Wei
ACS Applied Materials & Interfaces 2016 Volume 8(Issue 1) pp:232
Publication Date(Web):December 14, 2015
DOI:10.1021/acsami.5b08470
Germanium-based nanostructures are receiving intense interest in lithium-ion batteries because they have ultrahigh lithium ion storage ability. However, the Germanium-based anodes undergo the considerably large volume change during the charge/discharge processes, leading to a fast capacity fade. In the present work, a Ge/GeO2-ordered mesoporous carbon (Ge/GeO2–OMC) nanocomposite was successfully fabricated via a facile nanocasting route by using mesoporous carbon as a nanoreactor, and was then used as an anode for lithium-ion batteries. Benefited from its unique three-dimensional “meso-nano” structure, the Ge/GeO2–OMC nanocomposite exhibited large reversible capacity, excellent long-time cycling stability and high rate performance. For instance, a large reversible capacity of 1018 mA h g–1 was obtained after 100 cycles at a current density of 0.1 A g–1, which might be attributed to the unique structure of the Ge/GeO2–OMC nanocomposite. In addition, a reversible capacity of 492 mA h g–1 can be retained when cycled to 500 cycles at a current density of 1 A g–1.Keywords: Ge/GeO2−OMC; lithium-ion batteries; long cycle life; nanocomposite; nanoreactor
Co-reporter:Xun Sun, Yafeng Li, Jie Dou, Deli Shen, Mingdeng Wei
Journal of Power Sources 2016 Volume 322() pp:93-98
Publication Date(Web):1 August 2016
DOI:10.1016/j.jpowsour.2016.05.025
•MOF derived carbon materials were firstly applied as a counter electrode of DSCs.•An efficiency of 7.32% can achieved which was comparable to that of Pt electrode.•Calcination temperature influenced the properties of carbon counter-electrode.•The residual ZnO influenced the electrical conductivity of carbon counter-electrode.Metal-organic frameworks, ZIF-8, derived carbon materials are firstly applied as a counter electrode of dye-sensitized solar cells due to their easy fabrication, large specific surface area and high catalytic activities towards the reduction of I3− ions. An efficiency of 7.32% is achieved under the illumination of 1 sun (AM 1.5, 100 mW/cm2), which is comparable to that of the solar cell based on Pt electrode.Metal-organic frameworks (ZIF-8) derived carbon was firstly used as a counter electrode in dye-sensitized solar cells, and achieved an efficiency of 7.32%, which was comparable to that of Pt-based DSC.
Co-reporter:Zhensheng Hong, Jiaxing Hong, Chaobing Xie, Zhigao Huang, Mingdeng Wei
Electrochimica Acta 2016 Volume 202() pp:203-208
Publication Date(Web):1 June 2016
DOI:10.1016/j.electacta.2016.04.017
In this paper, we report a one-step and additive-free route for synthesizing hierarchical rutile TiO2 with mesocrystalline structure. The rutile TiO2 architecture constructed by oriented tiny nanorod subunits (around 5 nm in diameter) have nano/submicro hierarchical structures, nanoporous nature, a relatively large surface area and high tapped density. When the hierarchical rutile TiO2 was studied as anode material for Li-ion batteries (LIBs), they exhibited a high reversible capacity of more than 250 mAh g−1 within a voltage window of 1–3 V, superior rate capability and very good cycling stability with 220 mAh g−1 after 100 cycles at 0.1 A g−1. It’s notable that the hierarchical rutile TiO2 exhibited superior Li-ion storage properties under deep cycling conditions (0.01-3.0 V), a stable capacity of 346 mAh g−1 after 100 cycles at 0.1 A g−1 could be remained. The hierarchical TiO2 also displayed a large reversible capacity of more than 255 mAh g−1 (average value) at 0.05 A g−1 and good cycling performance for Na-ion insertion. These results, in combination with high volumetric storage capacity, render hierarchical rutile TiO2 a promising anode material for rechargeable batteries.
Co-reporter:Zhensheng Hong, Kaiqiang Zhou, Junwen Zhang, Zhigao Huang, and Mingdeng Wei
Crystal Growth & Design 2016 Volume 16(Issue 11) pp:6605
Publication Date(Web):October 10, 2016
DOI:10.1021/acs.cgd.6b01293
With the aim of enhancing the electrochemical kinetics and capacity of the TiO2 electrode for Na ion batteries (NIBs), we have designed a hybrid material of carbon-coated TiO2 mesocrystals anchored on reduced graphene oxide (TiO2@C-rGO). Such hybrid nanostructures are fabricated through a facile one-step route including in situ growth of oriented self-assembly of TiO2 mesocrystals on GO. TiO2@C-rGO possesses a very large surface area (279 m2 g–1), mesoporous nature, and single-crystal-like structure. It is also found that the capacity of TiO2 electrode for NIBs could be improved by carbon coating at a low current rate, but pure TiO2 shows better rate performance than that of TiO2@C. Remarkably, the enhanced electrochemical kinetics and large capacity can be simultaneously achieved by designing hybrid material. The hybrid nanostructures exhibit a highly reversible capacity of 300 mAh g–1 at 100 mA g–1, superior rate capability, and long-term cycling stability (a stable capacity of 159 mAh g–1 can be maintained after 1000 cycles at 1 A g–1). The superior Na ion storage of TiO2@C-rGO is largely ascribed to the robust architecture of well-dispersed carbon-coated mesoporous TiO2 mesocrystals anchored on conductive graphene network, leading to enhanced electrochemical kinetics and offering enough active sites for the Na ion to locate.
Co-reporter:Jie Dou, Yafeng Li, Fengyan Xie, Xiaokun Ding, and Mingdeng Wei
Crystal Growth & Design 2016 Volume 16(Issue 1) pp:121-125
Publication Date(Web):November 23, 2015
DOI:10.1021/acs.cgd.5b01003
Metal–organic frameworks (MOFs) have been generating a great deal of interest due to their high specific surface area, regular pore structure, and adjustable aperture. However, only a few studies explored their application in the field of photovoltaic devices. In the present work, MIL-125(Ti), one kind of MOFs, was investigated as the precursor for TiO2 photoanode of dye-sensitized solar cells for the first time. Herein, pure anatase TiO2 with a hierarchical structure was synthesized through the decomposition of MIL-125(Ti), which avoids the use of templates and fussy operation of sol–gel methods. The obtained TiO2 has a specific surface area of 147 m2 g–1 and a mean pore size value of 10 nm. When used as a photoanode material in dye-sensitized solar cells, the device gave rise to an overall energy conversion efficiency of 7.20%, which is better than the performance of the P25 based photoanode.
Co-reporter:Qingqing Sun 孙晴晴;Yafeng Li 李亚峰;Jie Dou 豆洁 魏明灯
Science China Materials 2016 Volume 59( Issue 10) pp:867-883
Publication Date(Web):2016 October
DOI:10.1007/s40843-016-5100-2
Dye-sensitized solar cells (DSSCs) provide a promising alternative solar cell technology because of their high efficiency, environmental friendliness, easy fabrication, and low cost. Power conversion efficiency is an important parameter to measure the performance of DSSCs, but the severe charge recombination that occurs at the photoanode hinders the future improvement of power conversion efficiency. Therefore, one of the key goals for achieving high efficiency is to reduce the energy loss caused by the unwanted charge recombination at various interfaces. From this perspective, surface modification of the photoanode is the simplest method among the various approaches available in the literature for enhancing the performance of DSSCs by inhibiting the interfacial charge recombination. After some brief notes on DSSCs, in this review, we present a comprehensive discussion on surface modifications of different photoanodes that have been adopted in the literature not only for reducing recombination but also for enhancing light harvesting. Depending on the electrode materials, we discuss surface modifications of binary oxides such as TiO2 and ZnO and ternary oxides, including Zn2SnO4, SrSnO3, and BaSnO3. We also talk about methods of surface modification and the materials suitable for surface treatment. Finally, we end with a brief future outlook of DSSCs.染料敏化太阳电池因其高效率、环境友好、制作工艺简单、生产成本低等优点而极具应用前景. 光电转换效率是衡量染料敏化太阳电池性能的重要参数之一, 然而光阳极上发生的电子复合阻碍了光电转换效率的进一步提高. 因此, 减少由各个界面处不利的电子复合引起的能量损失是提高光电转换效率的关键之一. 从这个方面来说, 光阳极表面修饰是抑制界面电子复合以提高染料敏化太阳电池光电转换效率的最简便方法之一. 这篇综述简单地介绍了染料敏化太阳电池的工作原理, 综合讨论了目前文献中所采用的不同光阳极的表面修饰方法. 这些表面修饰方法不仅能减少电子复合, 还能提高对太阳光的吸收. 根据光阳极材料的特点, 本文讨论了二元氧化物, 例如TiO2和ZnO, 以及包括Zn2SnO4、SrSnO3和BaSnO3在内的三元氧化物的表面修饰. 此外, 本文讨论了表面修饰的具体方法以及适用于表面处理的材料. 最后, 展望了染料敏化太阳电池的发展前景.
Co-reporter:Tongbin Lan, Jie Dou, Fengyan Xie, Peixun Xiong and Mingdeng Wei
Journal of Materials Chemistry A 2015 vol. 3(Issue 18) pp:10038-10044
Publication Date(Web):01 Apr 2015
DOI:10.1039/C5TA01061F
A facile one-step hydrothermal route was designed for preparing ultrathin TiO2-B nanowires, which were then hybridized with RGO to form a TiO2-B/RGO hybrid via an in situ approach, and both of them have a large BET surface area (231.6 m2 g−1 for TiO2-B nanowires and 256.1 m2 g−1 for the TiO2-B/RGO hybrid). It was found that the synthesized ultrathin nanowires are perpendicular to the [010] direction which is the most open channel in the TiO2-B crystal structure, demonstrating more Li-ion insertion/extraction hosts exposed to the electrolyte. Thus, the cell made of TiO2-B ultrathin nanowires exhibited large reversible lithium-ion charge–discharge capacity, excellent cycling stability and high-rate capability. When combined with RGO, the formed TiO2-B/RGO hybrid exhibited further improved Li storage performance. For instance, a capacity of 205.3 mA h g−1 was obtained at the fourth cycle and then faded slightly to 189.4 mA h g−1 after 300 cycles, demonstrating a surprising low average capacity fading of ca. 0.026% per cycle from 4th to 300th cycles.
Co-reporter:Yubin Liu, Minying Liu, Tongbin Lan, Jie Dou and Mingdeng Wei
Journal of Materials Chemistry A 2015 vol. 3(Issue 37) pp:18882-18888
Publication Date(Web):2015/08/07
DOI:10.1039/C5TA04870B
In the present work, Nb doped brookite TiO2 nanosheets were successfully synthesized via a one-step hydrothermal route. The synthesized samples were characterized by X-ray diffraction (XRD), Raman spectroscopy, scanning and transmission electron microscopy (SEM/TEM) and X-ray photoelectron spectroscopy (XPS). According to the experimental results, a possible mechanism for the formation of Nb doped brookite TiO2 nanosheets was proposed. Furthermore, Nb doped brookite TiO2 nanosheets were used as an anode material for the Li-ion intercalation reaction and it was found that their electronic/ionic conductivity was improved. At the same time, the cell made of Nb doped brookite TiO2 nanosheets also exhibited enhanced lithium-ion intercalation properties. For instance, this material displayed reversible capacities of 119.7 and 104.6 mA h g−1 at 5 C after 100 and 500 cycles, respectively.
Co-reporter:Zhensheng Hong, Kaiqiang Zhou, Junwen Zhang, Zhigao Huang and Mingdeng Wei
Journal of Materials Chemistry A 2015 vol. 3(Issue 33) pp:17412-17416
Publication Date(Web):27 Jul 2015
DOI:10.1039/C5TA04232A
With the aim of developing high performance anode (negative) materials for sodium ion batteries (NIBs), rutile TiO2 with mesocrystalline structure were designed and used for enhancing the discharge capacity and reaction kinetics. The nanoporous rutile TiO2 mesocrystals constructed by crystallographically oriented nanoparticle subunits with tunable microstructures were successfully prepared via a facile synthesis route. Such rutile TiO2 architecture possesses a large surface area (157 m2 g−1), nanoporous nature and single-crystal-like structure, which could provide a high level of accessibility for the electrolyte and more active sites, and allow the fast electron and ion transport compared with the irregularly oriented nanoparticles. When evaluated as an anode material for sodium-ion storage, this unique architecture exhibited a high reversible capacity over 350 mA h g−1 at 50 mA g−1, superior rate capability with a stable capacity of 151 mA h g−1 at 2 A g−1 and good cycling stability.
Co-reporter:Heyuan Qiu, Lingxing Zeng, Tongbin Lan, Xiaokun Ding and Mingdeng Wei
Journal of Materials Chemistry A 2015 vol. 3(Issue 4) pp:1619-1623
Publication Date(Web):18 Nov 2014
DOI:10.1039/C4TA05212A
A GeO2/RGO composite was successfully fabricated via alternating deposition of graphene oxide (GO) and GeO2 on the surface of a Ni foam substrate using a facile dip-coating method cooperated with in situ hydrolysis of GeCl4. This material was directly used as a binder-free anode for LIBs and exhibited high reversible capacity (1716 mA h g−1 at 0.2 A g−1, 702 mA h g−1 at 16 A g−1), good cycling performance (1159 mA h g−1 at 1 A g−1 after 500 cycles) and excellent rate capability. In addition, a reversible capacity as high as 621 mA h g−1 can be retained when cycled to 500 cycles at a rate as high as 8 A g−1.
Co-reporter:Huan Li, Hailong Fei, Xin Liu, Jie Yang and Mingdeng Wei
Chemical Communications 2015 vol. 51(Issue 45) pp:9298-9300
Publication Date(Web):04 May 2015
DOI:10.1039/C5CC02612A
Na2Ti7O15 nanotubes on a Ti net substrate were fabricated for the first time and used directly as a binder-free anode for Na-ion batteries. This material exhibited high reversible capacity and excellent stability which might be due to its unique characteristics including the porous substrate, nanoscale large surface area, nanotube structure and so on.
Co-reporter:Xin Liu, Zhiwei Li, Hailong Fei and Mingdeng Wei
Dalton Transactions 2015 vol. 44(Issue 43) pp:18864-18869
Publication Date(Web):02 Oct 2015
DOI:10.1039/C5DT03239C
A layer structured K-doped (NH4)2V3O8/graphene (K-NVG) was prepared via a hydrothermal route and then used as an anode material for sodium-ion batteries for the first time. The K-NVG nanosheets have a diameter in the range of 200–500 nm. The K-NVG electrode exhibited stable cycling and a good rate performance with a reversible capacity of 235.4 mA h g−1, which is much higher than the 90.5 mA h g−1 value of the (NH4)2V3O8/graphene electrode after 100 cycles at a current density of 100 mA g−1. Simultaneously, the retention rate was maintained at 82% even after 250 cycles at the current density of 300 mA g−1. Such good electrochemical properties may be attributed to the K-NVG's stable layered structure.
Co-reporter:Peixun Xiong, Guojin Zeng, Lingxing Zeng and Mingdeng Wei
Dalton Transactions 2015 vol. 44(Issue 38) pp:16746-16751
Publication Date(Web):25 Aug 2015
DOI:10.1039/C5DT03030G
In the present work, Prussian blue analogues, Mn[Fe(CN)6]0.6667·nH2O (Mn-PBA), were synthesized by a simple synthetic route and characterized by XRD, SEM, TEM, FTIR and TGA. When this material was firstly used as an anode for lithium-ion batteries, it exhibited a large capacity, good rate capability and cycling stability with a high Coulombic efficiency. For instance, a reversible capacity of 295.7 mA h g−1 can be achieved after 100 cycles at 200 mA g−1.
Co-reporter:Lingxing Zeng, Xiaoxia Huang, Cheng Zheng, Qingrong Qian, Qinghua Chen and Mingdeng Wei
Dalton Transactions 2015 vol. 44(Issue 17) pp:7967-7972
Publication Date(Web):20 Mar 2015
DOI:10.1039/C5DT00673B
Hierarchical LiZnVO4@C nanostructures composed of thin nanobelt aggregates were synthesized for the first time through an ethanol thermal and subsequent annealing route, and were investigated by X-ray diffraction (XRD), thermogravimetric analysis (TGA), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Furthermore, the synthesized hierarchical nanostructures were used as anode materials for Li-ion intercalation and exhibited a large reversible capacity, high rate performance, and excellent cycling stability. For instance, a high reversible capacity of 675 mA h g−1 was maintained after 60 cycles at a current density of 50 mA g−1. These results might be attributed to the following facts: (i) the hierarchical nanostructures could buffer the strain and volume changes during the cycling process; (ii) the thin nanobelts provide a shortened distance for Li-ion intercalation; (iii) the thin carbon layer on the surface of the nanobelts could provide a fast route for electron transportation, leading to an improved capacity and high rate performance.
Co-reporter:Peixun Xiong, Lingxing Zeng, Huan Li, Cheng Zheng and Mingdeng Wei
RSC Advances 2015 vol. 5(Issue 70) pp:57127-57132
Publication Date(Web):24 Jun 2015
DOI:10.1039/C5RA08779A
In the present work, nanocomposite Li3V2(PO4)3/carbon is successfully synthesized by combining a sol–gel method and a nanocasting route, and then it is characterized by means of X-ray diffraction (XRD), thermogravimetric analysis (TG), N2 adsorption–desorption, and transmission electron microscopy (TEM). Furthermore, this nanocomposite is used as a cathode material for Li-ion intercalation and exhibits large reversible capacity, high rate performance and excellent long-term cycling stability. For instance, a large reversible capacity of 95 mA h g−1 and an average Coulombic efficiency of 99.1% can be maintained even after 3000 cycles at a high rate of 20C in the potential range of 3.0–4.3 V. Moreover, the Li3V2(PO4)3/C nanocomposite delivered a large capacity of 127 mA h g−1 at a high rate of 10C in the voltage range of 3.0–4.8 V. The super results might be attributed to the unique hierarchical architecture of the Li3V2(PO4)3/carbon nanocomposite.
Co-reporter:Jie Yang, Cheng Zheng, Peixun Xiong, Yafeng Li and Mingdeng Wei
Journal of Materials Chemistry A 2014 vol. 2(Issue 44) pp:19005-19010
Publication Date(Web):26 Sep 2014
DOI:10.1039/C4TA04346D
A layered structural Zn-doped Ni-MOF was synthesized and, for the first time, used as an electrode material for a supercapacitor. It exhibited large specific capacitance, high rate capability and good cycling stability. Capacitances of 1620 and 854 F g−1 can be achieved at rates of 0.25 and 10 A g−1, respectively. Simultaneously, the retention was maintained at over 91% even after 3000 cycles. These values demonstrated the best performance of all the MOF materials in supercapacitor at present. Such an excellent electrochemical property may be attributed to the intrinsic characteristics of Zn-doped Ni-MOF material including its crystal structure and morphology.
Co-reporter:Jie Yang, Peixun Xiong, Cheng Zheng, Heyuan Qiu and Mingdeng Wei
Journal of Materials Chemistry A 2014 vol. 2(Issue 39) pp:16640-16644
Publication Date(Web):2014/08/18
DOI:10.1039/C4TA04140B
A layered structure Ni-based MOF was synthesized and, for the first time, was used as the electrode material for a supercapacitor. It exhibited large specific capacitance, high rate capability and cycling stability. Capacitances of 1127 and 668 F g−1 can be achieved at rates of 0.5 and 10 A g−1, respectively. At the same time, over 90% performance was retained after 3000 cycles. These excellent electrochemical properties may be related to the intrinsic characteristics of Ni-based MOF materials.
Co-reporter:Tongbin Lan, Yubin Liu, Jie Dou, Zhensheng Hong and Mingdeng Wei
Journal of Materials Chemistry A 2014 vol. 2(Issue 4) pp:1102-1106
Publication Date(Web):30 Oct 2013
DOI:10.1039/C3TA14178K
Hierarchically porous rutile TiO2 microspheres composed of nanorods were fabricated by using a facile synthetic route. These materials were characterized by X-ray diffraction (XRD), N2 adsorption–desorption, and scanning and transmission electron microscopy (SEM and TEM). Based on a series of experimental results, a self-assembly process for the formation of the hierarchical microspheres was also proposed. Furthermore, the hierarchically porous rutile TiO2 microspheres were used as the negative electrode material in lithium-ion batteries (LIBs) and demonstrated a large reversible charge–discharge capacity of 160.4 mA h g−1 after 100 cycles at 1 C, which was much greater than commercial rutile TiO2 under the same conditions, indicating that these materials had excellent cycling stability and high rate performance.
Co-reporter:Yubin Liu, Tongbin Lan, Weifeng Zhang, Xiaokun Ding and Mingdeng Wei
Journal of Materials Chemistry A 2014 vol. 2(Issue 47) pp:20133-20138
Publication Date(Web):2014/10/06
DOI:10.1039/C4TA04227A
In the present work, a one-step synthetic route is developed for fabricating hierarchical anatase TiO2 microspheres for the first time. These microspheres are composed of ultrathin rod-like structures in the radial direction, in which ultrathin rods consisted of tiny octahedra via a growth model of oriented attachment. Based on XRD and electron microscopic analyses, a mechanism for the growth of the microspheres is proposed. This material displays a large capacity of 157.3 mA h g−1 at 1 C after 200 cycles and also exhibits high rate performance and excellent cycling stability. These high performance characteristics may be due to the intrinsic characteristics of the hierarchical porous anatase TiO2 microspheres, in which the porous structure can permit facile diffusion of the electrolyte. They can also enhance the contact between the electrode surface and the electrolyte, while the ultrathin rods can shorten the transport distance of Li-ions and electrons during electrochemical cycling. At the same, the porous microsphere can also accommodate volume changes in the charge–discharge process.
Co-reporter:Jie Yang, Lifang Lian, Peixun Xiong and Mingdeng Wei
Chemical Communications 2014 vol. 50(Issue 45) pp:5973-5975
Publication Date(Web):07 Mar 2014
DOI:10.1039/C3CC49494B
Layered titanate H2Ti3O7 nanotubes were synthesized and firstly used as a supercapacitor electrode in a non-aqueous electrolyte. They exhibited the specific capacitances as high as 414 and 306 F g−1 at 0.5 and 10 A g−1, respectively, and 82% of the specific capacitance at the 10th cycle can be retained after 1000 cycles.
Co-reporter:Xun Sun, Jie Dou, Fengyan Xie, Yafeng Li and Mingdeng Wei
Chemical Communications 2014 vol. 50(Issue 69) pp:9869-9871
Publication Date(Web):04 Jul 2014
DOI:10.1039/C4CC03798G
NiS nanosheets on ITO substrates were synthesized with in situ growth via a one-step hydrothermal route, and exhibited an efficiency of 7.08% which was comparable to the solar cell based on the Pt electrode (7.01%) under the similar conditions.
Co-reporter:Yafeng Li, Zongzhou Che, Xun Sun, Jie Dou and Mingdeng Wei
Chemical Communications 2014 vol. 50(Issue 68) pp:9769-9772
Publication Date(Web):19 Jun 2014
DOI:10.1039/C4CC03352C
Metal–organic frameworks (MOFs) have been used in the area of photovoltaic devices via a novel approach proposed here for the first time. Hierarchical ZnO parallelepipeds were prepared from a MOF precursor, which could then act as an effective light scattering layer in dye-sensitized solar cells, leading to significantly improved cell performance.
Co-reporter:Jie Yang, Lifang Lian, Hongcheng Ruan, Fengyan Xie, Mingdeng Wei
Electrochimica Acta 2014 Volume 136() pp:189-194
Publication Date(Web):1 August 2014
DOI:10.1016/j.electacta.2014.05.074
Highlight•Nanostructured porous MnO2 film on Ni foam substrate was synthesized via a CV route for the first time.•The obtained MnO2 film has a 3D network structure and a high mass loading.•An asymmetry supercapacitor composed of MnO2 film (positive electrode) and active carbon (AC, negative electrode) was fabricated for the first time.•An asymmetric supercapacitor of AC//MnO2 displayed a capacitance of 67 F g−1 and an energy density of 37.22 Wh Kg−1.•The capacitance retention of 80% after 1000 cycles was reached for an asymmetric supercapacitor.Nanostructured porous MnO2 film on Ni foam substrate was fabricated via a CV electrodeposited route for the first time. The obtained MnO2 film had a 3D network structure and a high mass loading from 6 to 18 mg cm−2. This material achieved a maximum specific capacitance of 2790 mF cm−2 at 2 mA cm−2 and 864 mF cm-2 at 20 mA cm−2, and the specific capacitance can be retained above 90% after 1000 cycles at 5 mA cm−2. The fabricated AC//MnO2 asymmetric supercapacitor can reach a specific capacitance of 67 F g−1 and an energy density of 37.22 Wh Kg−1 with its capacitance retention of 80% after 1000 cycles at 2.5 mA cm−2.Nanostructured porous MnO2 films on Ni foam substrate were fabricated via a CV electrodeposited route for the first time and exhibited a maximum specific capacitance of 2790 mFcm−2 at 2 mA cm−2. An asymmetric supercapacitor of AC//MnO2 displayed a specific capacitance of 67 F g−1 and an energy density of 37.22 Wh Kg−1.
Co-reporter:Tingting Zhang, Qiaolin Lang, Lingxing Zeng, Tie Li, Mingdeng Wei, Aihua Liu
Electrochimica Acta 2014 Volume 115() pp:283-289
Publication Date(Web):1 January 2014
DOI:10.1016/j.electacta.2013.10.158
In this paper, the relationship between the electrochemical characteristics and the structure of a series of substituted phenol derivatives with electron-donating or electron-withdrawing groups were studied by voltammetry using ordered mesoporous carbons (OMCs) modified glassy carbon electrode (GCE) (OMCs/GCE). p-Nitrophenol (p-NP) and p-methylphenol were selected as models of electron-withdrawing and electron-donating groups, respectively, to illustrate the electrochemical behavior and reaction mechanism of substituted phenols. Voltammetric study showed that the oxidation peak potential (Epa) of substituted phenols with an electron-withdrawing group was systematically higher than that of substituted phenols with an electron-donating group. That is, the direct electrochemical oxidation of substituted phenol with an electron-withdrawing group is more difficult than that of substituted phenol with an electron-donating group. The Epa value shifted negatively with the increase of pKa for both p-substituted phenols and o-substituted phenols with the equations of pKa = −6.986 Epa + 13.261 (for p-substituted phenols) and pKa = −7.929 Epa + 13.831 (for o-substituted phenols). Thus, a simple and novel method was proposed for the precise prediction of the pKa of substituted phenols by determining Epa values with voltammetry at OMCs/GCE, which matched fairly with the results calculated from Hammett's constants. Thus, the present work may provide additional strategy to determine pKa values and investigate possible mechanisms of some organic reactions. In addition, by making use of the substituent effect, different p-substituted phenols (or o-substituted phenols) can be well separated and identified at OMCs/GCE by voltametry, which may find possible applications in simultaneous detection of p-substituted phenols (or o-substituted phenols).
Co-reporter:Cheng Zheng, Lingxing Zeng, Meili Wang, Huiyan Zheng and Mingdeng Wei
CrystEngComm 2014 vol. 16(Issue 44) pp:10309-10313
Publication Date(Web):23 Sep 2014
DOI:10.1039/C4CE01445F
Hierarchical ZnV2O4 microspheres were synthesized using an ethanol thermal reduction route for the first time, in which vanadium with a low valence can be formed. ZnV2O4 microspheres were characterized by X-ray diffraction (XRD), thermogravimetric analysis (TG), transmission electron microscopy (SEM/TEM) and N2 adsorption–desorption measurements. Furthermore, this material was used as an anode for Li ion intercalation and exhibited high reversible capacity, high rate performance, and good cycling stability. For instance, a high reversible capacity of 638 mA h g−1 was maintained after 280 cycles at a current density of 100 mA g−1. These results might be attributed to the facts that hierarchical ZnV2O4 microspheres could buffer the strain and volume changes during the charge–discharge cycling process, and provide more sites for Li ion storage and a shorter path for Li ion diffusion, leading to improved capacity and high rate performance.
Co-reporter:Caiyun Chen, Xiangzhen Zheng, Jie Yang and Mingdeng Wei
Physical Chemistry Chemical Physics 2014 vol. 16(Issue 37) pp:20073-20078
Publication Date(Web):04 Aug 2014
DOI:10.1039/C4CP02842B
ZnSn(OH)6 (ZSH) nanocubes with a uniform size of 40–80 nm were synthesized by using a simple hydrothermal route and then combined with graphene sheets (rGO) via the electrostatic interaction. The formed composite of ZnSn(OH)6 nanocube–graphene (ZSH–rGO) was used as an anode material for Li-ion batteries and it exhibited significantly enhanced electrochemical performance. For instance, a capacity of 540 mA h g−1 at 500 mA g−1 was retained after 40 cycles.
Co-reporter:Zhensheng Hong, Hong Dai, Zhigao Huang and Mingdeng Wei
Physical Chemistry Chemical Physics 2014 vol. 16(Issue 16) pp:7441-7447
Publication Date(Web):04 Mar 2014
DOI:10.1039/C4CP00718B
Anatase TiO2 mesocrystals and single crystals with dominant {101} facets were successfully synthesized without any additives using titanate nanowires as precursors under solvothermal and hydrothermal conditions, respectively. It is proposed that the oriented self-assembly process for the formation of TiO2 mesocrystals was controlled by the same thermodynamic principle as that of single crystals in this simple reaction system. Furthermore, the TiO2 mesocrystals were applied in photoelectrochemical (PEC) water splitting and demonstrated much enhanced photocurrent, almost 191% and 274% compared with that of TiO2 single crystals and commercial P25, respectively. Electrochemical impedance measurements under illumination revealed that the photocurrent increase was largely ascribed to the effective charge separation of electron–hole pairs and fast interfacial charge transfer. This could be attributed to the intrinsic characteristics of the mesostructured TiO2 composed of highly oriented nanocrystal subunits offering few grain boundaries, nanoporous nature and a short transport distance.
Co-reporter:Xiaomin Wu, Huan Li, Hailong Fei, Cheng Zheng and Mingdeng Wei
New Journal of Chemistry 2014 vol. 38(Issue 2) pp:584-587
Publication Date(Web):29 Oct 2013
DOI:10.1039/C3NJ00997A
In the present work, Li2MnO3 nanowires with a good electrochemical performance were synthesized by a simple molten-salt method, at a low temperature, using Mn2O3 nanowires with MnF2 as the Mn source. The discharge capacity of the Li2MnO3 nanowires used as the cathode material in a lithium-ion battery was up to 159.8 mA h g−1 after 27 cycles in a voltage range of 2.0 to 4.8 V at a current density of 20 mA g−1 at room temperature. They also displayed a good cycling stability and rate performance at different current densities.
Co-reporter:Caiyun Chen, Yafeng Li, Xun Sun, Fengyan Xie and Mingdeng Wei
New Journal of Chemistry 2014 vol. 38(Issue 9) pp:4465-4470
Publication Date(Web):24 Jun 2014
DOI:10.1039/C4NJ00729H
The surface treatment of zinc stannate (Zn2SnO4) film for use in dye-sensitized solar cells has been carried out with zinc tin oxide precursor solutions through chemical-bath deposition (CBD). Mott–Schottky measurements demonstrate that the flat band of Zn2SnO4 has a moderate positive shift owing to the surface treatment, which leads to a slightly decreased Voc. Although UV-vis spectroscopy reveals that the adsorption amounts of N719 and D131 dyes are decreased, EIS results and OCVD data suggest that the decreased charge recombination rate and prolonged electron lifetime give rise to an apparently improved efficiency of cells. Consequently, an enhancement of 13.5% is obtained after CBD surface treatment under the illumination of one sun (AM 1.5, 100 mW cm−2).
Co-reporter:Lifang Lian, Jie Yang, Peixun Xiong, Weifeng Zhang and Mingdeng Wei
RSC Advances 2014 vol. 4(Issue 77) pp:40753-40757
Publication Date(Web):26 Aug 2014
DOI:10.1039/C4RA07880B
Hierarchical MnO2 sub-microspheres were fabricated by using a simple, green and efficient low-temperature route. These sub-microspheres were formed via the aggregation of ultrathin nanosheets with a thickness of 2–4 nm. An electrode made of hierarchical MnO2 sub-microspheres exhibited a specific capacitance of 120 F g−1 at a current density of 0.167 A g−1. For an asymmetric AC//MnO2 supercapacitor, it exhibited a superior electrochemical stability in 1 M Na2SO4 aqueous solution with 88% retention of the initial specific capacitance after 1000 cycles, and the Coulombic efficiency was above 97%, indicating good charge–discharge reversibility and electrochemical stability.
Co-reporter:Aiying Pang, Xun Sun, Hongcheng Ruan, Yafeng Li, Songyuan Dai, Mingdeng Wei
Nano Energy 2014 Volume 5() pp:82-90
Publication Date(Web):April 2014
DOI:10.1016/j.nanoen.2014.02.007
•Hierarchical microspheres constructed from TiO2 cores and SnO2 shells have been fabricated.•The products were formed via a self-assembly process accompanied by the Kirkendall effect.•C106 dye sensitized TiO2@SnO2 microspheres exhibited an efficiency of 6.24%.Hierarchical microspheres constructed from a TiO2 core and a SnO2 shell have been successfully fabricated using a one-step solvothermal method. The synthesized products were characterized by XRD, SEM, TEM and FT-IR measurements. It was found that the concentration of precursor Sn4+ in the reaction system plays a key role in the formation of the hierarchical microspheres. The core–shell microspheres of TiO2@SnO2 were formed by a self-assembly process, accompanied by the Kirkendall effect. These core–shell microspheres of TiO2@SnO2 have been used for the first time as the electrode for C106 dye-sensitized solar cells; they exhibited an efficiency of 6.24%. This might be attributed to large surface area and hierarchical structure of the microspheres, leading to light scattering, an increase of dye adsorption, a suppression of charge recombination and prolonging the electron lifetime.Hierarchical microspheres constructed from a TiO2 core and a SnO2 shell have been fabricated using a facile solvothermal method. The concentration of precursor Sn4+ in the reaction system plays a key role in the formation of the hierarchical microspheres. These core–shell microspheres of TiO2@SnO2 have been used for the first time as the electrode for C106 dye-sensitized solar cells, exhibiting an efficiency of 6.24%.
Co-reporter:Dr. Yafeng Li;Caiyun Chen;Xun Sun;Jie Dou; Mingdeng Wei
ChemSusChem 2014 Volume 7( Issue 9) pp:2469-2472
Publication Date(Web):
DOI:10.1002/cssc.201402143
Abstract
ZIF-8, a kind of widely studied metal-organic frameworks, was used for the interfacial modification of dye-sensitized solar cells by a facile post-treatment strategy for the first time, which solved the problem of severely decreased short-circuit photocurrent in previous report. After the surface treatment, the performance of cells was obviously improved. The conditions for the deposition of ZIF-8 were optimized. The best photovoltaic property was obtained when the growth time of ZIF-8 was 7 min and the TiO2 photoanode was post-treated for 2 times. Besides the energy barrier effect of ZIF-8 that improved the open-circuit photovoltage and electron lifetime, the dyes adsorbed tightly on TiO2 surface was found to be a key point for the efficient electron injection and improved performance.
Co-reporter:Qixin Deng, Chaozhang Huang, Jianping Zhang, Wei Xie, Hanchun Xu and Mingdeng Wei
Nanoscale 2013 vol. 5(Issue 12) pp:5519-5523
Publication Date(Web):08 Apr 2013
DOI:10.1039/C3NR01246H
In this study, titanate nanosheets, nanotubes, and nanowires, were synthesized by hydrothermal treatment anatase TiO2 in different temperatures. The obtained products are characterized by X-ray powder diffraction (XRD), scanning electron microscopy (SEM), transmission electron micrograph (TEM) and Brunauer–Emmett–Teller (BET) nitrogen sorption–desorption measurement. Then, the nanostructural titanates were used as additives for selectively reducing tobacco-specific nitrosamines (TNSAs) in mainstream cigarette smoke (CS) for the first time. These nanomaterials exhibited high reduction ability of TSNAs which was related to their intrinsic properties. The N–NO functional group of TSNAs with a negative charge would react with H+ on the surface of nanomaterials via chemical absorption and can be retained on the surface of the titanates. Among these materials, titanate nanowires (TNW) captured more TNSAs owing to their network structure, which resulted in the selective reduction ratio of TSNAs being improved significantly. Thus, TNW is a useful additive for selectively reducing the TSNAs in CS without changing the cigarette flavor.
Co-reporter:Zhensheng Hong and Mingdeng Wei
Journal of Materials Chemistry A 2013 vol. 1(Issue 14) pp:4403-4414
Publication Date(Web):08 Jan 2013
DOI:10.1039/C2TA01312F
Ti-based materials have been intensively investigated and considered as good potential negative electrode materials for lithium-ion batteries (LIBs) due to their high safety, superior rate capability and excellent cyclic stability. This feature article summarizes the recent progress of a new class of layered titanate (H2TinO2n+1·H2O) nanostructures and their derivatives, including TiO2 polymorphs, novel titanate nanostructures of Zn2Ti3O8, Li2MTi3O8 (M = Co, Zn, Mg) and Li4Ti5O12, as high performance negative electrode materials for LIBs. The effects of the composition, crystal structure and morphology on lithium-ion intercalation properties are highlighted and analyzed.
Co-reporter:Lingxing Zeng, Cheng Zheng, Lunchao Xia, Yaxian Wang and Mingdeng Wei
Journal of Materials Chemistry A 2013 vol. 1(Issue 13) pp:4293-4299
Publication Date(Web):21 Jan 2013
DOI:10.1039/C3TA10275K
A nanocomposite of ordered mesoporous pure anatase TiO2–C was successfully synthesized for the first time by using ordered mesoporous carbon as a nano-reactor and exhibited a short-range ordered mesoporous structure. It was found that carbon was coated on the surface of TiO2 nanoparticles to form a thin layer. Using this material as an anode in rechargeable lithium-ion batteries, it displayed a large reversible capacity, high rate performance and excellent long-term cycling stability. For instance, a large reversible capacity of 166 mA h g−1 and an average Coulombic efficiency of 99.7% could be maintained even after 900 cycles at a current rate of 1 C. This can be attributed to the structure of the ordered mesoporous TiO2–C nanocomposite. Such a nanostructure provides both electron and lithium-ion pathways which are essential for rechargeable lithium-ion batteries with a large capacity and excellent long-term performance.
Co-reporter:Lingxing Zeng, Cheng Zheng, Cuilin Deng, Xiaokun Ding, and Mingdeng Wei
ACS Applied Materials & Interfaces 2013 Volume 5(Issue 6) pp:2182
Publication Date(Web):February 25, 2013
DOI:10.1021/am303286n
In the present work, the nanocomposite of MoO2-ordered mesoporous carbon (MoO2–OMC) was synthesized for the first time using a carbon thermal reduction route and the mesoporous carbon as the nanoreactor. The synthesized nanocomposite was characterized by X-ray diffraction (XRD), thermogravimetric analysis (TGA), N2 adsorption–desorption, scanning electron microscopy (SEM), and transmission electron microscopy (TEM) measurements. Furthermore, this nanocomposite was used as an anode material for Li-ion intercalation and exhibited large reversible capacity, high rate performance, and good cycling stability. For instance, a high reversible capacity of 689 mAh g–1 can remain after 50 cycles at a current density of 50 mA g–1. It is worth mentioning that the MoO2–OMC nanocomposite electrode can attain a high reversible capacity of 401 mAh g–1 at a current density as high as 2 A g–1. These results might be due to the intrinsic characteristics of nanocomposite, which offered a better accommodation of the strain and volume changes and a shorter path for Li-ion and electron transport, leading to the improved capacity and enhanced rate capability.Keywords: anode; carbon thermal reduction; lithium-ion batteries; MoO2−OMC;
Co-reporter:Lingxing Zeng, Cheng Zheng, Jingchao Xi, Hailong Fei, Mingdeng Wei
Carbon 2013 Volume 62() pp:382-388
Publication Date(Web):October 2013
DOI:10.1016/j.carbon.2013.06.021
The composites of V2O3–ordered mesoporous carbon (V2O3–OMC) were synthesized and used as anode materials for Li-ion intercalation. These materials exhibited large reversible capacity, high rate performance and excellent cycling stability. For instance, a reversible capacity of V2O3–OMC composites was 536 mA h g−1 after 180 cycles at a current density of 0.1 A g−1. The high electrochemical performance of the V2O3–OMC composites is attributed to the anchoring of nanoparticles on mesoporous carbon for improving the electrochemical active of V2O3 particles for energy storage applications in high performance lithium-ion batteries.
Co-reporter:Aiying Pang, Lunchao Xia, Haiyan Luo, Yafeng Li, Mingdeng Wei
Electrochimica Acta 2013 Volume 94() pp:92-97
Publication Date(Web):1 April 2013
DOI:10.1016/j.electacta.2013.01.128
Highly crystalline titania nanorods were prepared from H2Ti3O7 nanotubes precursor and then used as the photoanode for indoline dyes sensitized solar cells. The cells sensitized by D131, D102 and D149 dyes exhibited the efficiencies of 4.63%, 4.56% and 5.47%, respectively. Interestingly, the photovoltaic properties can be enhanced significantly when the mixed dye was used as a sensitizer. The best efficiency of 7.30% was obtained using the mixed dye of D131 and D149 as a sensitizer. This result might be ascribed to the increased light-harvesting, prolonged electron lifetime and inhibited interfacial charge recombination.Highlights► Highly crystalline H2Ti3O7 nanotubes were successfully synthesized and used as an electrode precursor for indoline dyes sensitized solar cells. ► The photovoltaic properties can be enhanced significantly when two indoline dyes were used as a co-sensitizer. ► The best efficiency of 7.30% was obtained for a cell sensitized by a mixed dye of D131 and D149.
Co-reporter:Tingting Zhang, Qiaolin Lang, Dapeng Yang, Liang Li, Lingxing Zeng, Cheng Zheng, Tie Li, Mingdeng Wei, Aihua Liu
Electrochimica Acta 2013 Volume 106() pp:127-134
Publication Date(Web):1 September 2013
DOI:10.1016/j.electacta.2013.05.055
In this paper, ordered mesoporous carbons (OMCs) modified glassy carbon electrode (GCE) (OMCs/GCE) was employed to investigate the electrochemical behavior of o-nitrophenol (o-NP), m-nitrophenol (m-NP) and p-nitrophenol (p-NP) in ambient–N2 phosphate buffer saline. Compared with bare GCE, the OMCs/GCE exhibited obvious electrocatalytic activity towards nitrophenol isomers. The electrochemical reaction mechanism of nitrophenol at the modified electrode was also studied. At OMCs/GCE, the three nitrophenol isomers could be identified and separated successfully and the simultaneous determination was realized by detecting the reduction peaks of their intermediate products (at 0.209 V vs. saturated calomel electrode for p-NP, 0.020 V for m-NP and −0.201 V for o-NP) with differential pulse voltammetry. Under the optimized experimental conditions, the linear ranges of the calibration curves were 2–90 μM for p-NP, 1–100 μM for m-NP and 0.5–90 μM for o-NP with limits of detection of 0.1 μM, 0.06 μM and 0.08 μM for p-NP, m-NP and o-NP, respectively (S/N = 3). Therefore, the proposed method is simple, rapid, stable, sensitive, specific, reproducible and cost-effective, which can be applicable for real samples detection.
Co-reporter:Jie Yang, Tongbin Lan, Jingdong Liu, Yanfang Song, Mingdeng Wei
Electrochimica Acta 2013 Volume 105() pp:489-495
Publication Date(Web):30 August 2013
DOI:10.1016/j.electacta.2013.05.023
•Hollow V2O5 spheres constructed from plate-like particles were synthesized and used as supercapacitor electrodes in a solution of 5 M LiNO3.•These materials exhibited a tremendous pseudocapacitance effect with a high capacitance of 479 F g−1 at 5 mV s−1.•The hollow V2O5 spheres was coated with PPy exhibited the capacitances of 559 F g−1 at 3 A g−1 by GCD and 566 F g−1 at 5 mV s−1 by CV, respectively.Hollow V2O5 spheres constructed from plate-like particles were synthesized. These materials exhibited a tremendous pseudocapacitance effect with a high capacitance of 479 F g−1 at 5 mV s−1 when used as supercapacitor electrodes in a solution of 5 M LiNO3. After the surface of hollow V2O5 spheres was coated with PPy, the composite electrode was formed and its electrochemical properties were also improved. This composite material exhibited the capacitances of 559 F g−1 at 3 A g−1 by GCD and 566 F g−1 at 5 mV s−1 by CV, respectively. At the same time, the capacity retentions of 70% and 66% were respectively achieved even after 100 cycles.Hollow V2O5 spheres constructed from plate-like particles exhibited a tremendous pseudocapacitance effect with a high capacitance of 479 F g−1.
Co-reporter:Yuxia Xu, Zhensheng Hong, Lunchao Xia, Jie Yang, Mingdeng Wei
Electrochimica Acta 2013 Volume 88() pp:74-78
Publication Date(Web):15 January 2013
DOI:10.1016/j.electacta.2012.10.044
One step sol–gel route was developed for synthesizing Li2ZnTi3O8/C nanocomposite, in which a thin layer of carbon was coated on the surface of Li2ZnTi3O8 nanoparticles. These nanoparticles were high crystalline and their size was found to be ca. 20–30 nm. The synthesized Li2ZnTi3O8/C nanocomposite was used as an anode for rechargeable lithium-ion batteries and exhibited a high reversible charge–discharge capacity, excellent cycling stability and high rate performance. A large capacity of 284 mAh g−1 can be kept after 200 cycles at a current density of 0.2 A g−1. These results can be attributed to the intrinsic characteristics of Li2ZnTi3O8/C nanocomposite. A thin layer of carbon on the surface of Li2ZnTi3O8 nanoparticles could improve significantly the conductivity and the anode made of nanoparticles greatly decreased the diffusion distance for lithium ions and electrons in the solid state.Graphical abstractThe spinel Li2ZnTi3O8 nanoparticles coated with a thin layer of carbon were successfully synthesized and exhibited a high reversible charge-discharge capacity, excellent cycling stability and high rate performance.Highlights► The spinel Li2ZnTi3O8/C nanocomposite was synthesized by using a one step sol–gel route. ► A thin layer of carbon with 2–3 nm was formed on the surface of Li2ZnTi3O8 nanoparticles. ► Li2ZnTi3O8/C nanocomposite exhibited a high reversible charge–discharge capacity, excellent cycling stability and high rate performance.
Co-reporter:Xiaokun Ding, Hongcheng Ruan, Cheng Zheng, Jie Yang and Mingdeng Wei
CrystEngComm 2013 vol. 15(Issue 15) pp:3040-3044
Publication Date(Web):18 Feb 2013
DOI:10.1039/C3CE27097A
A simple synthetic route was developed for the synthesis of anatase TiO2 nanoparticles with tunable dominant exposed facets. These nanoparticles were characterized by XRD, TEM, XPS and EDS measurements. The F− ions displayed a key role in the hydrothermal reaction for the formation of anatase TiO2 with different exposed facets (010), (001) and (106), which were decided by the different connection models of Ti–OH. Furthermore, a possible mechanism for the formation of anatase TiO2 with different exposed facets was suggested.
Co-reporter:Yonggang Wang;Zhensheng Hong;Yongyao Xia
Advanced Functional Materials 2012 Volume 22( Issue 24) pp:5185-5193
Publication Date(Web):
DOI:10.1002/adfm.201200766
Abstract
Layered H2Ti6O13-nanowires are prepared using a facile hydrothermal method and their Li-storage behavior is investigated in non-aqueous electrolyte. The achieved results demonstrate the pseudocapacitive characteristic of Li-storage in the layered H2Ti6O13-nanowires, which is because of the typical nanosize and expanded interlayer space. The as-prepared H2Ti6O13-nanowires have a high capacitance of 828 F g−1 within the potential window from 2.0 to 1.0 V (vs. Li/Li+). An asymmetric supercapacitor with high energy density is developed successfully using H2Ti6O13-nanowires as a negative electrode and ordered mesoporous carbon (CMK-3) as a positive electrode in organic electrolyte. The asymmetric supercapacitor can be cycled reversibly in the voltage range of 1 to 3.5 V and exhibits maximum energy density of 90 Wh kg−1, which is calculated based on the mass of electrode active materials. This achieved energy density is much higher than previous reports. Additionally, H2Ti6O13//CMK-3 asymmetric supercapacitor displays the highest average power density of 11 000 W kg−1. These results indicate that the H2Ti6O13//CMK-3 asymmetric supercapacitor should be a promising device for fast energy storage.
Co-reporter:Lingxing Zeng, Fuyu Xiao, Jingchao Wang, Shaokang Gao, Xiaokun Ding and Mingdeng Wei
Journal of Materials Chemistry A 2012 vol. 22(Issue 28) pp:14284-14288
Publication Date(Web):22 May 2012
DOI:10.1039/C2JM32138F
In the present work, the nanocomposite ZnV2O4–CMK was synthesized for the first time by using a low temperature carbothermal reduction route and was then characterized by means of X-ray diffraction (XRD), thermogravimetric analysis (TG), N2 adsorption–desorption, scanning and transmission electron microscopy (SEM/TEM). Furthermore, the nanocomposite was used for the first time as an anode material for Li-ion intercalation and exhibited a large reversible capacity, high rate performance and cycling stability. A reversible capacity of 575 mA h g−1 was maintained even after 200 cycles at a current density of 0.1 A g−1. These results might be due to the intrinsic characteristics of the nanocomposite offering a large surface area providing more sites for Li-ion insertion and a shorter path for Li-ion and electron transport, leading to improved capacity and enhanced rate capability.
Co-reporter:Xiangzhen Zheng, Yafeng Li, Yuxia Xu, Zhensheng Hong and Mingdeng Wei
CrystEngComm 2012 vol. 14(Issue 6) pp:2112-2116
Publication Date(Web):13 Jan 2012
DOI:10.1039/C2CE06350F
A MOF material ZIF-8 was used to coat the surface of Zn2SnO4 (ZTO) nanoparticles for the first time and the core/shell structure of ZTO/ZIF-8 nanocomposites were formed. Anode materials composed of ZTO/ZIF-8 nanocomposites exhibited larger charge capacities and good cycling performance, indicating that the thin layer of ZIF-8 on the surface of ZTO nanoparticles was beneficial to improving electrochemical properties. These might be attributed to the fact that the conductivity of electrode material can be greatly increased after the surface of ZTO nanoparticles was coated by ZIF-8. On the other hand, the nanoporous ZIF-8 on the electrodes was in favor of the release of the stress caused by the drastic volume expansion during Li–Sn alloying/de-alloying process, resulting in an obvious improvement of electrochemical property.
Co-reporter:Aiying Pang, Caiyun Chen, Ling Chen, Wei Liu and Mingdeng Wei
RSC Advances 2012 vol. 2(Issue 25) pp:9565-9570
Publication Date(Web):08 Aug 2012
DOI:10.1039/C2RA21144K
ZnO QDs were successfully synthesized by using a simple synthetic route. The synthesized ZnO QDs have different shapes with highly crystalline nature and their size was found to be ca. 3–5 nm. At the same time, a series of modified N719 dyes were obtained via ion-exchange reactions and characterized by FTIR and HRMS measurements. When the modified N719 dyes were used as a sensitizer for ZnO QDs-based flexible solar cells, the photovoltaic properties were enhanced significantly. A highest efficiency of 2.94% was achieved; this might be attributed to the fact that the aggregate of Zn2+/dye on the surface of ZnO QDs can be suppressed efficiently owing to a less carboxylated (COOH) bipyridyl ligand in the modified N719 dye, inhibiting the formation of chelation between ZnO QDs and dye.
Co-reporter:Huixing Zhang, Yafeng Li, Zhensheng Hong, Mingdeng Wei
Materials Letters 2012 Volume 79() pp:148-151
Publication Date(Web):15 July 2012
DOI:10.1016/j.matlet.2012.03.105
Co-reporter:Aiying Pang, Yafeng Li, Huixing Zhang, Yangzhong Wang, Mingdeng Wei
Materials Chemistry and Physics 2012 Volume 135(Issue 1) pp:46-50
Publication Date(Web):16 July 2012
DOI:10.1016/j.matchemphys.2012.03.109
Ti1−xSnxO2 nanocrystals were successfully synthesized by using a simple solvothermal route, and its band energy gap broaden and flat band potential can be rationally regulated with increasing x value. Furthermore, Ti1−xSnxO2 nanocrystals were first used as the photoelectrode material for dye-sensitized solar cells. A cell made of Ti1−xSnxO2 (x = 0.3) exhibited the best photovoltaic performance. This is due to its most narrow band gap energies, most negative flat band potential and lowest dark current densities. After the surface of Ti1−xSnxO2 (x = 0.3) electrode was treated with TiCl4 solution, the cell sensitized by a mixed solution of N719 and D131 dye exhibited the best efficiency of 4.64% under the illumination of 1 sun (AM1.5, 100 mW cm−2).Highlights► Ti1−xSnxO2 nanocrystals were used as an electrode for dye-sensitized solar cells. ► The efficiency can be improved obviously after the electrode was treated with TiCl4. ► The best efficiency of 4.64% was obtained using a mixed solution of N719 and D131.
Co-reporter:Zhensheng Hong, Mingdeng Wei, Tongbin Lan, Guozhong Cao
Nano Energy 2012 Volume 1(Issue 3) pp:466-471
Publication Date(Web):May 2012
DOI:10.1016/j.nanoen.2012.02.009
Wulff-shaped and nanorod-like nanoporous mesocrystals constructed from ultrathin rutile TiO2 nanowires were successfully fabricated for the first time in the presence of the surfactant sodium dodecyl benzene sulfonate (SDBS). SDBS played a key role in the homoepitaxial self-assembly process, in which titanate nanowires were used as the primary building blocks for forming mesocrystals accompanying with a simultaneous phase transition. The nanoporous rutile TiO2 mesocrystals have a large surface area and were subjected to detailed structural characterization by means of X-ray diffraction (XRD), scanning and transmission electron microscopy (SEM/TEM) including high-resolution TEM (HRTEM) and selected area electron diffraction (SAED). Furthermore, the nanoporous rutile TiO2 mesocrystals were applied as the electrode materials in rechargeable lithium-ion batteries and demonstrated a large reversible charge–discharge capacity, excellent cycling stability and high rate performance. These properties were attributed to the intrinsic characteristic of the mesoscopic structured TiO2 with nanoporous nature and larger surface area (which favored fast Li-ion transport), as well as the presence of sufficient void space to accommodate the volume change.Graphical AbstractWulff-shaped and nanorod-like nanoporous mesocrystals constructed from ultrathin rutile TiO2 nanowires were successfully fabricated for the first time and were applied as the electrode materials in rechargeable lithium-ion batteries; they demonstrated a large reversible charge–discharge capacity, excellent cycling stability and high rate performance.Highlights► Wulff-shaped and nanorod-like mesocrystals form from ultrathin rutile TiO2 nanowires. ► TiO2 mesocrystals are promising anode material for high-power lithium-ion batteries. ► Large reversible charge–discharge capacity and excellent cycling stability. ► Enhanced properties from nanoporosity, large surface area and sufficient void space.
Co-reporter:Yafeng Li, Binbin Guo, Xiangzhen Zheng, Aiying Pang, Mingdeng Wei
Electrochimica Acta 2012 60() pp: 66-70
Publication Date(Web):
DOI:10.1016/j.electacta.2011.11.019
Co-reporter:Zhensheng Hong;Yuxia Xu;Yubin Liu ; Mingdeng Wei
Chemistry - A European Journal 2012 Volume 18( Issue 34) pp:10753-10760
Publication Date(Web):
DOI:10.1002/chem.201200515
Abstract
Unique ordered TiO2 superstructures with tunable morphology and crystalline phase were successfully prepared by the use of different counterions. Dumbbell-shaped rutile TiO2 and nanorod-like rutile mesocrystals constructed from ultrathin nanowires, and quasi-octahedral anatase TiO2 mesocrystals built from tiny nanoparticle subunits were achieved. Interestingly, the obtained anatase mesocrystals have a fine microporous structure and a large surface area. The influence of the counterions in the reaction system is discussed and possible mechanisms responsible for the formation of the unique ordered TiO2 superstructures with different morphologies and crystalline phases are also proposed based on a series of experimental results. The obtained TiO2 superstructures were used as anode materials in lithium ion batteries, and exhibited higher capacity and improved rate performance; this is attributed to the intrinsic characteristics of the mesoscopic TiO2 superstructures, which have a single-crystal-like and porous nature.
Co-reporter:Dr. Yafeng Li;Ya Wang;Caiyun Chen;Aiying Pang; Mingdeng Wei
Chemistry - A European Journal 2012 Volume 18( Issue 37) pp:11716-11722
Publication Date(Web):
DOI:10.1002/chem.201201047
Abstract
The performance of dye-sensitized ZnO solar cells was improved by a facile surface-treatment approach through chemical-bath deposition. After the surface treatment, the quantum dots of Zn2SnO4 were deposited onto ZnO nanoparticles accompanied by the aggregations of Zn2SnO4 nanoparticles. The ZnO film displayed a better resistance to acidic dye solution on account of the deposited Zn2SnO4 nanoparticles. Meanwhile, the open-circuit photovoltage was greatly enhanced, which can be ascribed to the increased conduction-band edge of ZnO and inhibited interfacial charge recombination. Although the deposition of Zn2SnO4 decreased the adsorption amounts of N719 dye, the aggregates of Zn2SnO4 with a size of 350–450 nm acted as the effective light-scattering layer, thereby resulting in an improved short-circuit photocurrent. By co-sensitizing 10 μm-thick ZnO film with N719 and D131 dyes, a top efficiency of 4.38 % was achieved under the illumination of one sun (AM 1.5, 100 mW cm−2).
Co-reporter:Zhensheng Hong, Xiangzhen Zheng, Xiaokun Ding, Lilong Jiang, Mingdeng Wei and Kemei Wei
Energy & Environmental Science 2011 vol. 4(Issue 5) pp:1886-1891
Publication Date(Web):14 Apr 2011
DOI:10.1039/C0EE00833H
Complex spinel titanate Li2MTi3O8 (M = Co, Zn, Co0.5Zn0.5) nanowires have been synthesized via a simple synthetic route using titanate nanowires as a precursor. The nanowires are highly crystalline and have been used for the first time as the anode material in a rechargeable lithium-ion battery. The battery has exhibited a highly reversible charge-discharge capacity and excellent cycling stability, even at a current density as high as 3.2 A g−1. This result can be attributed to the intrinsic characteristics of spinel Li2MTi3O8 nanowires. A three-dimensional network could provide a diffusion space for lithium ion insertion into and extraction from the anode material, resulting in very good cycle performance, even at a high rate.
Co-reporter:Yafeng Li, Aiying Pang, Changju Wang and Mingdeng Wei
Journal of Materials Chemistry A 2011 vol. 21(Issue 43) pp:17259-17264
Publication Date(Web):28 Sep 2011
DOI:10.1039/C1JM12754C
Metal–organic frameworks (MOFs) were used for the first time to coat TiO2 to enhance the open circuit voltage (Voc) of dye-sensitized solar cells (DSC). ZIF-8 was selected as a representative MOF for a case study. After a growth time of 30 min, a very thin ZIF-8 film was coated on TiO2 with a thickness of about 2 nm. A linear relationship between the thickness of ZIF-8 coating layer and the Voc is found, and the value of Voc was increased by 55 and 66 mV for the dye N719 and D131, respectively. Mott–Schottky measurement demonstrated that the enhanced Voc was not caused by the changed conduction band edge of TiO2 due to its possible coordination with 2-methyl imidazole. The electrochemical impedance spectra and I–V characteristics of the cells measured under dark conditions indicated the increased Voc could be ascribed to the inhibited interfacial charge recombination due to the introduction of ZIF-8 shell material. Although the amount of adsorption of dyes for the TiO2/ZIF-8 electrode was increased significantly, the core/shell structure inhibited the injection of electrons from dyes into the conduction band edge of TiO2, which decreased the short circuit current.
Co-reporter:Qixin Deng, Chaozhang Huang, Wei Xie, Jianping Zhang, Yiqiang Zhao, Zhensheng Hong, Aiying Pang and Mingdeng Wei
Chemical Communications 2011 vol. 47(Issue 21) pp:6153-6155
Publication Date(Web):26 Apr 2011
DOI:10.1039/C1CC10794A
Titanate nanosheets and nanotubes have first been introduced into cigarette filter, a great range of harmful compounds including tar, nicotine, ammonia, hydrogen cyanide, selected carbonyls and phenolic compounds can be reduced efficiently.
Co-reporter:Qunfang Li, Lingxing Zeng, Jinchao Wang, Dianping Tang, Bingqian Liu, Guonan Chen, and Mingdeng Wei
ACS Applied Materials & Interfaces 2011 Volume 3(Issue 4) pp:1366
Publication Date(Web):March 30, 2011
DOI:10.1021/am200228k
This study demonstrates a facile and feasible strategy toward the development of advanced electrochemical immunosensors based on chemically functionalized magnetic mesoporous organic−inorganic hybrid nanomaterials, and the preparation, characterization, and measurement of relevant properties of the immunosensor for detection of carcinoembryonic antigen (CEA, as a model analyte) in clinical immunoassays. The as-prepared nanomaterials composed of a magnetic mesoporous NiCo2O4 nanosheet, an interlayer of Nafion/thionine organic molecules and a nanogold layer show good adsorption properties for the attachment of horseradish peroxidase-labeled secondary anti-CEA antibody (HRP-anti-CEA). With a sandwich-type immunoassay format, the functional bionanomaterials present good analytical properties to facilitate and modulate the way it was integrated onto the electrochemical immunosensors, and allows the detection of CEA at a concentration as low as 0.5 pg/mL. Significantly, the immunosensor could be easily regenerated by only using an external magnet without the need of any dissociated reagents. Importantly, the as-synthesized magnetic mesoporous NiCo2O4 nanomaterials could be further extended for detection of other biomarkers or biocompounds.Keywords: carcinoembryonic antigen; electrochemical immunosensor; magnetic organic−inorganic hybrid nanomaterials; mesoporous NiCo2O4 nanosheets
Co-reporter:Yafeng Li, Xiangzhen Zheng, Huixing Zhang, Binbin Guo, Aiying Pang, Mingdeng Wei
Electrochimica Acta 2011 Volume 56(Issue 25) pp:9257-9261
Publication Date(Web):30 October 2011
DOI:10.1016/j.electacta.2011.08.006
The dye-sensitized Zn2SnO4 solar cells were treated with Al3+ ions to enhance the power conversion efficiency for the first time. Usually, the surface treatment on photoanodes with Al3+ ions generated an overlayer of Al2O3. For Zn2SnO4 photoanode, another reaction pathway was found. The treatment with Al3+ ions led to decreasing open circuit voltage, and a 22.6% enhancement of efficiency. Mott–Schottky measurements revealed that the flat band of Zn2SnO4 had a positive shift owing to the introduction of Al3+ ions. XPS confirmed that Al3+ ions were introduced into the lattice of Zn2SnO4 and occupied the position of Sn4+, resulting in decreased conduction band edge. TEM demonstrated the size of Zn2SnO4 nanoparticles became larger due to the reaction of Al3+ with Zn2SnO4. Although the adsorption amounts of dyes lowered by 21%, the driving force for electron injection was greatly enhanced as a result of decreased conduction band edge, resulting in significantly enhanced cell efficiency.Highlights► The power conversion efficiency of dye-sensitized Zn2SnO4 solar cells was enhanced by the surface treatment of Al3+ ions for the first time. ► The treatment with Al3+ ions led to decreasing open circuit voltage, and an 18.5% enhancement of efficiency. ► Al3+ ions were introduced into the lattice of Zn2SnO4 and occupied the position of Sn4+, resulting in decreased conduction band edge of Zn2SnO4. ► The driving force for electron injection was greatly enhanced as a result of decreased conduction band edge.
Co-reporter:Hailong Fei, Mingdeng Wei
Electrochimica Acta 2011 Volume 56(Issue 20) pp:6997-7004
Publication Date(Web):1 August 2011
DOI:10.1016/j.electacta.2011.05.127
A facile hydrothermal method is developed to prepare rutile titania sub-microflowers consisting of nanorods with oxalic acid and TiOSO4 as reagents. The diameter of sub-microflowers and nanorods is found to be ca. 800 and 40 nm, respectively. Also, the shape and size of building blocks in rutile titania sub-microflowers can be considerably controlled via adjusting the reaction time and reactant amounts. Rutile titania sub-microflowers composed of nanorods display higher discharge capacity and better rate cycle stability than other rutile titania nanostructures as lithium-ion battery anode material due to enhancing the Li-ion transfer rate for small size building blocks.Highlights► Rutile TiO2 sub-microflowers and sub-microspheres with different building blocks as anode materials of lithium-ion battery. ► Controllable morphologies with oxalic acid by the hydrothermal technique. ► Sub-microflower and sub-microspheres constructed by well organized nanorods exhibited high capacity and good cycle stability. ► Small size building blocks nanorods enhance the transfer rate of Li-ion.
Co-reporter:Yafeng Li, Aiying Pang, Xiangzhen Zheng, Mingdeng Wei
Electrochimica Acta 2011 Volume 56(Issue 13) pp:4902-4906
Publication Date(Web):1 May 2011
DOI:10.1016/j.electacta.2011.02.071
The ternary oxide zinc stannate (Zn2SnO4) nanoparticles are first used as the electrode materials for the quantum dot sensitized solar cells. CdS quantum dots are utilized to sensitize Zn2SnO4 electrode via a chemical bath deposition technique. The covering of ZnS layer, the kinds of conducting substrates and the thickness of film are optimized to improve the cell performance. The optimal film thickness is found to be 6.4 μm, and the electrode prepared at sixth CBD cycle exhibits a highest efficiency of 0.228% under the illumination of 1 sun (AM1.5, 100 mW cm−2).Highlights► Ternary oxide Zn2SnO4 is first used as the electrode material for quantum-dot-sensitized solar cells. ► CdS quantum dots are prepared via chemical bath deposition to sensitize Zn2SnO4 film. ► SEM images confirm the mesopores of Zn2SnO4 films. ► ZnS treated Zn2SnO4 electrode with a film thickness of 6.4 μm exhibits a best performance at sixth cycle with the cell parameters of Jsc = 0.524 mA cm−2, Voc = 0.524 V, FF = 0.526 and η = 0.228% under the illumination of one sun (AM1.5, 100 mW cm−2).
Co-reporter:Haiyan Luo, Mingdeng Wei, Kemei Wei
Journal of Alloys and Compounds 2011 Volume 509(Issue 3) pp:864-867
Publication Date(Web):21 January 2011
DOI:10.1016/j.jallcom.2010.09.114
In this paper, the nanobelts of molybdenum oxide amine composite were successfully synthesized via a redox-assisted molecular assembly route under the hydrothermal conditions. The synthesized nanobelts were characterized by XRD, SEM, TEM, TG and FT-IR measurements. The thickness of nanobelts is found to be ca. 20–30 nm and their lengths are up to several tens of micrometers. Based on a series of the experimental results, a possible model, redox-intercalation-exfoliation, was suggested for the formation of nanobelts of molybdenum oxide amine composite.Research highlights▶ Nanobelts of molybdenum oxide amine were first synthesized via a redox-assisted molecular assembly route. ▶ These nanobelts are highly crystalline with a several tens of micrometers in length and 20–30 nm in thickness.
Co-reporter:Chunlong Zheng, Xiangzhen Zheng, Zhensheng Hong, Xiaokun Ding, Mingdeng Wei
Materials Letters 2011 Volume 65(Issue 11) pp:1645-1647
Publication Date(Web):15 June 2011
DOI:10.1016/j.matlet.2011.02.061
In the present work, SnO2 nanostructural hollow spheres have been successfully synthesized in the absence of template by a simple synthetic route, and their surfaces were covered by nanorods. The synthesized nanostructural hollow spheres covered by nanorods were further characterized by XRD, SEM and TEM measurements. The diameter of SnO2 hollow spheres and the thickness of shells are found to be ca. 150–200 and 20–30 nm, respectively. The size of the nanorod is found to be ca. 5 nm, and the length up to tens of nanometers. Based on a series of experimental results, an oxidizing-aggregating-Ostwald ripening model has been proposed for the formation of SnO2 nanostructural hollow spheres.
Co-reporter:Hailong Fei, Xiaokun Ding, Mingdeng Wei, Kemei Wei
Solid State Sciences 2011 Volume 13(Issue 11) pp:2049-2054
Publication Date(Web):November 2011
DOI:10.1016/j.solidstatesciences.2011.09.009
Hydrothermal carbonization of sucrose was used to controllably synthesize Montroseite VOOH and Paramontroseite VO2 nanoparticles carbonaceous core-shell microspheres. After calcinations, V2O3-VO2-C core-shell microspheres were obtained. When they were used as cathode materials in lithium-ion battery (LIB), it was found that Montroseite VOOH carbonaceous core-shell microspheres exhibited higher discharge capacity than Paramontroseite VO2 counterpart, while the content of V2O3 had some large effects on the electrochemical properties of V2O3-VO2C core-shell microspheres.
Co-reporter:Zhensheng Hong, Mingdeng Wei, Qixin Deng, Xiaokun Ding, Lilong Jiang and Kemei Wei
Chemical Communications 2010 vol. 46(Issue 5) pp:740-742
Publication Date(Web):25 Nov 2009
DOI:10.1039/B916681E
Ternary oxide Zn2Ti3O8 nanowires were first synthesized and used as the anode material in a rechargeable lithium-ion battery, which displayed a very reversible charge–discharge capacity and excellent cycling stability.
Co-reporter:Lihua Huang, Lilong Jiang, Mingding Wei
Electrochemistry Communications 2010 Volume 12(Issue 2) pp:319-322
Publication Date(Web):February 2010
DOI:10.1016/j.elecom.2009.12.030
Zn2SnO4 nanocrystals were synthesized and first used as the electrode materials for the metal-free indoline dyes sensitized solar cells (DSSCs). The highest efficiency of 3.08% was achieved for a D131 DSSC. This might be attributed to the fact that the D131 dye has a greater positive oxidation potential, which can lead to rapid dye regeneration, avoiding the geminate charge recombination between oxidized dye molecules and injected electrons in the Zn2SnO4 film. The efficiency can be improved significantly using a mixture solution of D131 and N719 dyes for which an efficiency of 3.6% was obtained.
Co-reporter:Zhensheng Hong, Mingdeng Wei, Xiaokun Ding, Lilong Jiang, Kemei Wei
Electrochemistry Communications 2010 Volume 12(Issue 6) pp:720-723
Publication Date(Web):June 2010
DOI:10.1016/j.elecom.2010.03.016
Spinel Li2ZnTi3O8 nanorods were first synthesized using titanate nanowires as a precursor. The synthesized nanorods are highly crystalline and used as an anode material in a rechargeable Li-ion battery. A large capacity of 220 mA h g− 1 was kept after 30 cycles at a current density of 0.1 A g− 1, which is close to the theoretic capacity. The electrochemical measurements indicate that the anode material made of spinel Li2ZnTi3O8 nanorods displayed a highly reversible capacity and excellent cycling stability.
Co-reporter:Wenda Huang, Shaokang Gao, Xiaokun Ding, Lilong Jiang, Mingdeng Wei
Journal of Alloys and Compounds 2010 Volume 495(Issue 1) pp:185-188
Publication Date(Web):9 April 2010
DOI:10.1016/j.jallcom.2010.01.116
MnV2O6 nanobelts have successfully been synthesized via a hydrothermal route. The obtained nanobelts are highly crystalline and their thickness is found to be ca. 20–30 nm. These nanobelts were first used as the anode materials in a rechargeable lithium-ion battery, which exhibits a very reversible discharge/charge capacity and excellent cycling stability even at a current density as high as 1 A g−1. This might be attributed to the intrinsic characteristics of MnV2O6 nanobelts.
Co-reporter:Haiyan Luo, Mingdeng Wei, Kemei Wei
Materials Chemistry and Physics 2010 Volume 120(Issue 1) pp:6-9
Publication Date(Web):15 March 2010
DOI:10.1016/j.matchemphys.2009.10.053
In this study, Nb2O5 nanosheets were first synthesized using NbO2 particles as the precursor via a simple hydrothermal route. The synthesized Nb2O5 nanosheets are highly crystalline and their thicknesses are found to be ca. 3–5 nm. Based on the experimental results of XRD, SEM and TEM measurements, a possible mechanism for the formation of nanosheets was discussed. An electrode materials made of the product containing Nb2O5 nanosheets shows a larger capacity of 355 mAh g−1 at a current density of 0.1 A g−1. Cyclic measurements indicate that such an electrode exhibits a high reversible charge/discharge capacity and cycling stability. This might be attributed to the intrinsic characteristics of Nb2O5 nanosheets.
Co-reporter:Zhanjun Chen, Shaokang Gao, Lilong Jiang, Mingdeng Wei, Kemei Wei
Materials Chemistry and Physics 2010 Volume 121(1–2) pp:254-258
Publication Date(Web):15 May 2010
DOI:10.1016/j.matchemphys.2010.01.032
In this study, VO2 (B) nanorods were successfully synthesized using a simple hydrothermal route, in which templates or catalysts were absent. The synthesized VO2 (B) nanorods are highly crystalline and have a rectangular cross-section. Following this, a possible model, reacting-exfoliating-recrystallizing, was proposed for the formation of VO2 (B) nanorods. A lithium battery using VO2 (B) nanorods as the active material of the positive electrode exhibits a high initial discharge capacity of 605 mAh g−1, revealing the formation of Li1.82VO2. Such a high degree of electrochemical performance is attributed to the intrinsic properties of crystalline VO2 (B) nanorods.
Co-reporter:Shaokang Gao, Zhanjun Chen, Mingdeng Wei, Kemei Wei, Haoshen Zhou
Electrochimica Acta 2009 Volume 54(Issue 3) pp:1115-1118
Publication Date(Web):1 January 2009
DOI:10.1016/j.electacta.2008.08.043
In this study, single crystal V3O7·H2O nanobelts were successfully synthesized using a simple hydrothermal route, in which templates or catalysts were absent. The synthesized V3O7·H2O nanobelts are highly crystalline and have lengths up to several tens of micrometers. The width and thickness of the nanobelts are found to be about 30–50 and 30 nm, respectively. A lithium battery using V3O7·H2O nanobelts as the positive electrode exhibits a high initial discharge capacity of 409 mAh g−1, corresponding to the formation of LixV3O7·H2O (x = 4.32). Such a high degree of electrochemical performance is attributed to the intrinsic properties of the single-crystalline V3O7·H2O nanobelts.
Co-reporter:Haiyan Luo, Mingdeng Wei, Kemei Wei
Materials Chemistry and Physics 2009 Volume 113(Issue 1) pp:85-90
Publication Date(Web):15 January 2009
DOI:10.1016/j.matchemphys.2008.07.059
In this study, a new metastable phase of crystallized MoO3·0.3H2O nanobelts was successfully synthesized using a simple synthetic route. The synthesized nanobelts are highly crystalline and have lengths up to several tens of micrometers. Based on the experimental observations, a possible reaction model, solid–solution–solid, was proposed for the formation of the nanobelt structures.
Co-reporter:Qixin Deng, Mingdeng Wei, Xiaokun Ding, Lilong Jiang, Binghuo Ye and Kemei Wei
Chemical Communications 2008 (Issue 31) pp:3657-3659
Publication Date(Web):13 Jun 2008
DOI:10.1039/B802896F
Brookite-type TiO2nanotubes with crystalline multilayer walls have been synthesized for the first time via a simple hydrothermal route.
Co-reporter:Mingdeng Wei, Kewei Wei, M. Ichihara, Haoshen Zhou
Electrochemistry Communications 2008 Volume 10(Issue 8) pp:1164-1167
Publication Date(Web):August 2008
DOI:10.1016/j.elecom.2008.05.014
In this study, H2Ti3O7 nanowires were successfully synthesized via a hydrothermal process and post-treatments. The diameter of the nanowires is found to be about 30 nm and the length up to several micrometers. A lithium battery using H2Ti3O7 nanowires as the active material of the positive electrode exhibits a discharge capacity of 100 mA hg−1 and still keeps stable after 200 cycles at a current density as high as 40 Ag−1, demonstrating excellent high rate performance.
Co-reporter:Mingdeng Wei, Kemei Wei, Masaki Ichihara, Haoshen Zhou
Electrochemistry Communications 2008 Volume 10(Issue 7) pp:980-983
Publication Date(Web):July 2008
DOI:10.1016/j.elecom.2008.04.031
In this study, Nb2O5 nanobelts, with a ca. ∼15 nm in thickness, ca. ∼60 nm in width and several tens of mircrometers in length, have first been used as the electrode material for lithium intercalation over the potential window of 3.0–1.2 V (vs. Li+/Li). It delivers an initial intercalation capacity of 250 mA hg−1 at 0.1 Ag−1 current density, corresponding to x = 2.5 for LxNb2O5, and can still keep relative stable and reaches as large as 180 mA hg−1 after 50 cycles. Surprisingly, the electrodes composed of Nb2O5 nanobelts can work smoothly even at high current density of 10 Ag−1, and shows higher specific capacity and excellent cycling stable, as well as sloped feature in voltage profile. Cycling test indicates Nb2O5 nanobelts electrode shows a high reversible charge/discharge capacity, high rate capability with excellent cycling stability.
Co-reporter:Zhanjun Chen, Shaokang Gao, Ronghua Li, Mingdeng Wei, Kemei Wei, Haoshen Zhou
Electrochimica Acta 2008 Volume 53(Issue 28) pp:8134-8137
Publication Date(Web):30 November 2008
DOI:10.1016/j.electacta.2008.06.014
In this study, ultra-thin nanobelts of Ag2V4O11/Ag were successfully synthesized. The synthesized ultra-thin nanobelts of Ag2V4O11/Ag are highly crystalline and the thickness is found to be about 5 nm. A lithium battery using ultra-thin nanobelts of Ag2V4O11/Ag as the active materials of the positive electrode exhibits a high initial discharge capacity of 276 mAh g−1, corresponding to the formation of LixAg2V4O11 (x = 6). With increased cycling, the electrode made of ultra-thin nanobelts of Ag2V4O11/Ag tends to loose electrochemical activity due to Ag+ ions in the ultra-thin nanobelts of Ag2V4O11 were reduced and new phase was formed.
Co-reporter:Qixin Deng, Mingdeng Wei, Xiaokun Ding, Lilong Jiang, Kewei Wei, Haoshen Zhou
Journal of Crystal Growth (1 January 2010) Volume 312(Issue 2) pp:213-219
Publication Date(Web):1 January 2010
DOI:10.1016/j.jcrysgro.2009.10.050
In this study, large single-crystal anatase TiO2 bipyramids were first successfully synthesized using a simple hydrothermal route. The synthesized bipyramids were characterized by XRD, SEM and TEM measurements, and found that these bipyramids are highly crystalline anatase TiO2 with a size up to 3.6 μm between the two ends. On the other hand, it was also found that the size and shape of bipyramids were significantly influenced by the pH value. Based on a series of experimental results, a possible model for the process of dissolving-coalescing-growing, has been proposed for the formation of large anatase TiO2 bipyramids.
Co-reporter:Hailong Fei, Huan Li, Zhiwei Li, Wenjing Feng, Xin Liu and Mingdeng Wei
Dalton Transactions 2014 - vol. 43(Issue 43) pp:NaN16527-16527
Publication Date(Web):2014/09/03
DOI:10.1039/C4DT02002B
A simple and versatile method for preparation of new crystalline graphite nitrate-like ammonium vanadium bronze (NH4)0.19V2O5·0.44H2O nano-microstructures is developed via a simple hydrothermal route following heat treatment. (NH4)0.19V2O5·0.44H2O platelets are tested as a novel high-energy cathode material for sodium-ion batteries. The enhancement of electrochemical performance for a (NH4)0.19V2O5·0.44H2O platelet electrode is offered by addition of graphene and using graphite nitrate-like ammonium vanadium bronze microflowers. A graphene-based graphite nitrate-like vanadium bronze microflower composite shows a higher discharge capacity of 208.9 A h g−1 for the second cycle in a 1.5–3.4 V voltage limit at a discharge current density of 20 mA g−1. The reversible capacity of 141.5 A h g−1 remained after 40 cycles.
Co-reporter:Yafeng Li, Aiying Pang, Changju Wang and Mingdeng Wei
Journal of Materials Chemistry A 2011 - vol. 21(Issue 43) pp:NaN17264-17264
Publication Date(Web):2011/09/28
DOI:10.1039/C1JM12754C
Metal–organic frameworks (MOFs) were used for the first time to coat TiO2 to enhance the open circuit voltage (Voc) of dye-sensitized solar cells (DSC). ZIF-8 was selected as a representative MOF for a case study. After a growth time of 30 min, a very thin ZIF-8 film was coated on TiO2 with a thickness of about 2 nm. A linear relationship between the thickness of ZIF-8 coating layer and the Voc is found, and the value of Voc was increased by 55 and 66 mV for the dye N719 and D131, respectively. Mott–Schottky measurement demonstrated that the enhanced Voc was not caused by the changed conduction band edge of TiO2 due to its possible coordination with 2-methyl imidazole. The electrochemical impedance spectra and I–V characteristics of the cells measured under dark conditions indicated the increased Voc could be ascribed to the inhibited interfacial charge recombination due to the introduction of ZIF-8 shell material. Although the amount of adsorption of dyes for the TiO2/ZIF-8 electrode was increased significantly, the core/shell structure inhibited the injection of electrons from dyes into the conduction band edge of TiO2, which decreased the short circuit current.
Co-reporter:Zhensheng Hong and Mingdeng Wei
Journal of Materials Chemistry A 2013 - vol. 1(Issue 14) pp:NaN4414-4414
Publication Date(Web):2013/01/08
DOI:10.1039/C2TA01312F
Ti-based materials have been intensively investigated and considered as good potential negative electrode materials for lithium-ion batteries (LIBs) due to their high safety, superior rate capability and excellent cyclic stability. This feature article summarizes the recent progress of a new class of layered titanate (H2TinO2n+1·H2O) nanostructures and their derivatives, including TiO2 polymorphs, novel titanate nanostructures of Zn2Ti3O8, Li2MTi3O8 (M = Co, Zn, Mg) and Li4Ti5O12, as high performance negative electrode materials for LIBs. The effects of the composition, crystal structure and morphology on lithium-ion intercalation properties are highlighted and analyzed.
Co-reporter:Lingxing Zeng, Cheng Zheng, Lunchao Xia, Yaxian Wang and Mingdeng Wei
Journal of Materials Chemistry A 2013 - vol. 1(Issue 13) pp:NaN4299-4299
Publication Date(Web):2013/01/21
DOI:10.1039/C3TA10275K
A nanocomposite of ordered mesoporous pure anatase TiO2–C was successfully synthesized for the first time by using ordered mesoporous carbon as a nano-reactor and exhibited a short-range ordered mesoporous structure. It was found that carbon was coated on the surface of TiO2 nanoparticles to form a thin layer. Using this material as an anode in rechargeable lithium-ion batteries, it displayed a large reversible capacity, high rate performance and excellent long-term cycling stability. For instance, a large reversible capacity of 166 mA h g−1 and an average Coulombic efficiency of 99.7% could be maintained even after 900 cycles at a current rate of 1 C. This can be attributed to the structure of the ordered mesoporous TiO2–C nanocomposite. Such a nanostructure provides both electron and lithium-ion pathways which are essential for rechargeable lithium-ion batteries with a large capacity and excellent long-term performance.
Co-reporter:Yubin Liu, Tongbin Lan, Weifeng Zhang, Xiaokun Ding and Mingdeng Wei
Journal of Materials Chemistry A 2014 - vol. 2(Issue 47) pp:NaN20138-20138
Publication Date(Web):2014/10/06
DOI:10.1039/C4TA04227A
In the present work, a one-step synthetic route is developed for fabricating hierarchical anatase TiO2 microspheres for the first time. These microspheres are composed of ultrathin rod-like structures in the radial direction, in which ultrathin rods consisted of tiny octahedra via a growth model of oriented attachment. Based on XRD and electron microscopic analyses, a mechanism for the growth of the microspheres is proposed. This material displays a large capacity of 157.3 mA h g−1 at 1 C after 200 cycles and also exhibits high rate performance and excellent cycling stability. These high performance characteristics may be due to the intrinsic characteristics of the hierarchical porous anatase TiO2 microspheres, in which the porous structure can permit facile diffusion of the electrolyte. They can also enhance the contact between the electrode surface and the electrolyte, while the ultrathin rods can shorten the transport distance of Li-ions and electrons during electrochemical cycling. At the same, the porous microsphere can also accommodate volume changes in the charge–discharge process.
Co-reporter:Jie Yang, Cheng Zheng, Peixun Xiong, Yafeng Li and Mingdeng Wei
Journal of Materials Chemistry A 2014 - vol. 2(Issue 44) pp:NaN19010-19010
Publication Date(Web):2014/09/26
DOI:10.1039/C4TA04346D
A layered structural Zn-doped Ni-MOF was synthesized and, for the first time, used as an electrode material for a supercapacitor. It exhibited large specific capacitance, high rate capability and good cycling stability. Capacitances of 1620 and 854 F g−1 can be achieved at rates of 0.25 and 10 A g−1, respectively. Simultaneously, the retention was maintained at over 91% even after 3000 cycles. These values demonstrated the best performance of all the MOF materials in supercapacitor at present. Such an excellent electrochemical property may be attributed to the intrinsic characteristics of Zn-doped Ni-MOF material including its crystal structure and morphology.
Co-reporter:Huan Li, Hailong Fei, Xin Liu, Jie Yang and Mingdeng Wei
Chemical Communications 2015 - vol. 51(Issue 45) pp:NaN9300-9300
Publication Date(Web):2015/05/04
DOI:10.1039/C5CC02612A
Na2Ti7O15 nanotubes on a Ti net substrate were fabricated for the first time and used directly as a binder-free anode for Na-ion batteries. This material exhibited high reversible capacity and excellent stability which might be due to its unique characteristics including the porous substrate, nanoscale large surface area, nanotube structure and so on.
Co-reporter:Jie Yang, Lifang Lian, Peixun Xiong and Mingdeng Wei
Chemical Communications 2014 - vol. 50(Issue 45) pp:NaN5975-5975
Publication Date(Web):2014/03/07
DOI:10.1039/C3CC49494B
Layered titanate H2Ti3O7 nanotubes were synthesized and firstly used as a supercapacitor electrode in a non-aqueous electrolyte. They exhibited the specific capacitances as high as 414 and 306 F g−1 at 0.5 and 10 A g−1, respectively, and 82% of the specific capacitance at the 10th cycle can be retained after 1000 cycles.
Co-reporter:Yafeng Li, Zongzhou Che, Xun Sun, Jie Dou and Mingdeng Wei
Chemical Communications 2014 - vol. 50(Issue 68) pp:NaN9772-9772
Publication Date(Web):2014/06/19
DOI:10.1039/C4CC03352C
Metal–organic frameworks (MOFs) have been used in the area of photovoltaic devices via a novel approach proposed here for the first time. Hierarchical ZnO parallelepipeds were prepared from a MOF precursor, which could then act as an effective light scattering layer in dye-sensitized solar cells, leading to significantly improved cell performance.
Co-reporter:Xun Sun, Jie Dou, Fengyan Xie, Yafeng Li and Mingdeng Wei
Chemical Communications 2014 - vol. 50(Issue 69) pp:NaN9871-9871
Publication Date(Web):2014/07/04
DOI:10.1039/C4CC03798G
NiS nanosheets on ITO substrates were synthesized with in situ growth via a one-step hydrothermal route, and exhibited an efficiency of 7.08% which was comparable to the solar cell based on the Pt electrode (7.01%) under the similar conditions.
Co-reporter:Zhensheng Hong, Mingdeng Wei, Qixin Deng, Xiaokun Ding, Lilong Jiang and Kemei Wei
Chemical Communications 2010 - vol. 46(Issue 5) pp:NaN742-742
Publication Date(Web):2009/11/25
DOI:10.1039/B916681E
Ternary oxide Zn2Ti3O8 nanowires were first synthesized and used as the anode material in a rechargeable lithium-ion battery, which displayed a very reversible charge–discharge capacity and excellent cycling stability.
Co-reporter:Zhensheng Hong, Kaiqiang Zhou, Junwen Zhang, Zhigao Huang and Mingdeng Wei
Journal of Materials Chemistry A 2015 - vol. 3(Issue 33) pp:NaN17416-17416
Publication Date(Web):2015/07/27
DOI:10.1039/C5TA04232A
With the aim of developing high performance anode (negative) materials for sodium ion batteries (NIBs), rutile TiO2 with mesocrystalline structure were designed and used for enhancing the discharge capacity and reaction kinetics. The nanoporous rutile TiO2 mesocrystals constructed by crystallographically oriented nanoparticle subunits with tunable microstructures were successfully prepared via a facile synthesis route. Such rutile TiO2 architecture possesses a large surface area (157 m2 g−1), nanoporous nature and single-crystal-like structure, which could provide a high level of accessibility for the electrolyte and more active sites, and allow the fast electron and ion transport compared with the irregularly oriented nanoparticles. When evaluated as an anode material for sodium-ion storage, this unique architecture exhibited a high reversible capacity over 350 mA h g−1 at 50 mA g−1, superior rate capability with a stable capacity of 151 mA h g−1 at 2 A g−1 and good cycling stability.
Co-reporter:Tongbin Lan, Yubin Liu, Jie Dou, Zhensheng Hong and Mingdeng Wei
Journal of Materials Chemistry A 2014 - vol. 2(Issue 4) pp:NaN1106-1106
Publication Date(Web):2013/10/30
DOI:10.1039/C3TA14178K
Hierarchically porous rutile TiO2 microspheres composed of nanorods were fabricated by using a facile synthetic route. These materials were characterized by X-ray diffraction (XRD), N2 adsorption–desorption, and scanning and transmission electron microscopy (SEM and TEM). Based on a series of experimental results, a self-assembly process for the formation of the hierarchical microspheres was also proposed. Furthermore, the hierarchically porous rutile TiO2 microspheres were used as the negative electrode material in lithium-ion batteries (LIBs) and demonstrated a large reversible charge–discharge capacity of 160.4 mA h g−1 after 100 cycles at 1 C, which was much greater than commercial rutile TiO2 under the same conditions, indicating that these materials had excellent cycling stability and high rate performance.
Co-reporter:Lingxing Zeng, Fuyu Xiao, Jingchao Wang, Shaokang Gao, Xiaokun Ding and Mingdeng Wei
Journal of Materials Chemistry A 2012 - vol. 22(Issue 28) pp:NaN14288-14288
Publication Date(Web):2012/05/22
DOI:10.1039/C2JM32138F
In the present work, the nanocomposite ZnV2O4–CMK was synthesized for the first time by using a low temperature carbothermal reduction route and was then characterized by means of X-ray diffraction (XRD), thermogravimetric analysis (TG), N2 adsorption–desorption, scanning and transmission electron microscopy (SEM/TEM). Furthermore, the nanocomposite was used for the first time as an anode material for Li-ion intercalation and exhibited a large reversible capacity, high rate performance and cycling stability. A reversible capacity of 575 mA h g−1 was maintained even after 200 cycles at a current density of 0.1 A g−1. These results might be due to the intrinsic characteristics of the nanocomposite offering a large surface area providing more sites for Li-ion insertion and a shorter path for Li-ion and electron transport, leading to improved capacity and enhanced rate capability.
Co-reporter:Caiyun Chen, Xiangzhen Zheng, Jie Yang and Mingdeng Wei
Physical Chemistry Chemical Physics 2014 - vol. 16(Issue 37) pp:NaN20078-20078
Publication Date(Web):2014/08/04
DOI:10.1039/C4CP02842B
ZnSn(OH)6 (ZSH) nanocubes with a uniform size of 40–80 nm were synthesized by using a simple hydrothermal route and then combined with graphene sheets (rGO) via the electrostatic interaction. The formed composite of ZnSn(OH)6 nanocube–graphene (ZSH–rGO) was used as an anode material for Li-ion batteries and it exhibited significantly enhanced electrochemical performance. For instance, a capacity of 540 mA h g−1 at 500 mA g−1 was retained after 40 cycles.
Co-reporter:Zhensheng Hong, Hong Dai, Zhigao Huang and Mingdeng Wei
Physical Chemistry Chemical Physics 2014 - vol. 16(Issue 16) pp:NaN7447-7447
Publication Date(Web):2014/03/04
DOI:10.1039/C4CP00718B
Anatase TiO2 mesocrystals and single crystals with dominant {101} facets were successfully synthesized without any additives using titanate nanowires as precursors under solvothermal and hydrothermal conditions, respectively. It is proposed that the oriented self-assembly process for the formation of TiO2 mesocrystals was controlled by the same thermodynamic principle as that of single crystals in this simple reaction system. Furthermore, the TiO2 mesocrystals were applied in photoelectrochemical (PEC) water splitting and demonstrated much enhanced photocurrent, almost 191% and 274% compared with that of TiO2 single crystals and commercial P25, respectively. Electrochemical impedance measurements under illumination revealed that the photocurrent increase was largely ascribed to the effective charge separation of electron–hole pairs and fast interfacial charge transfer. This could be attributed to the intrinsic characteristics of the mesostructured TiO2 composed of highly oriented nanocrystal subunits offering few grain boundaries, nanoporous nature and a short transport distance.
Co-reporter:Jie Yang, Peixun Xiong, Cheng Zheng, Heyuan Qiu and Mingdeng Wei
Journal of Materials Chemistry A 2014 - vol. 2(Issue 39) pp:NaN16644-16644
Publication Date(Web):2014/08/18
DOI:10.1039/C4TA04140B
A layered structure Ni-based MOF was synthesized and, for the first time, was used as the electrode material for a supercapacitor. It exhibited large specific capacitance, high rate capability and cycling stability. Capacitances of 1127 and 668 F g−1 can be achieved at rates of 0.5 and 10 A g−1, respectively. At the same time, over 90% performance was retained after 3000 cycles. These excellent electrochemical properties may be related to the intrinsic characteristics of Ni-based MOF materials.
Co-reporter:Yubin Liu, Minying Liu, Tongbin Lan, Jie Dou and Mingdeng Wei
Journal of Materials Chemistry A 2015 - vol. 3(Issue 37) pp:NaN18888-18888
Publication Date(Web):2015/08/07
DOI:10.1039/C5TA04870B
In the present work, Nb doped brookite TiO2 nanosheets were successfully synthesized via a one-step hydrothermal route. The synthesized samples were characterized by X-ray diffraction (XRD), Raman spectroscopy, scanning and transmission electron microscopy (SEM/TEM) and X-ray photoelectron spectroscopy (XPS). According to the experimental results, a possible mechanism for the formation of Nb doped brookite TiO2 nanosheets was proposed. Furthermore, Nb doped brookite TiO2 nanosheets were used as an anode material for the Li-ion intercalation reaction and it was found that their electronic/ionic conductivity was improved. At the same time, the cell made of Nb doped brookite TiO2 nanosheets also exhibited enhanced lithium-ion intercalation properties. For instance, this material displayed reversible capacities of 119.7 and 104.6 mA h g−1 at 5 C after 100 and 500 cycles, respectively.
Co-reporter:Tongbin Lan, Jie Dou, Fengyan Xie, Peixun Xiong and Mingdeng Wei
Journal of Materials Chemistry A 2015 - vol. 3(Issue 18) pp:NaN10044-10044
Publication Date(Web):2015/04/01
DOI:10.1039/C5TA01061F
A facile one-step hydrothermal route was designed for preparing ultrathin TiO2-B nanowires, which were then hybridized with RGO to form a TiO2-B/RGO hybrid via an in situ approach, and both of them have a large BET surface area (231.6 m2 g−1 for TiO2-B nanowires and 256.1 m2 g−1 for the TiO2-B/RGO hybrid). It was found that the synthesized ultrathin nanowires are perpendicular to the [010] direction which is the most open channel in the TiO2-B crystal structure, demonstrating more Li-ion insertion/extraction hosts exposed to the electrolyte. Thus, the cell made of TiO2-B ultrathin nanowires exhibited large reversible lithium-ion charge–discharge capacity, excellent cycling stability and high-rate capability. When combined with RGO, the formed TiO2-B/RGO hybrid exhibited further improved Li storage performance. For instance, a capacity of 205.3 mA h g−1 was obtained at the fourth cycle and then faded slightly to 189.4 mA h g−1 after 300 cycles, demonstrating a surprising low average capacity fading of ca. 0.026% per cycle from 4th to 300th cycles.
Co-reporter:Heyuan Qiu, Lingxing Zeng, Tongbin Lan, Xiaokun Ding and Mingdeng Wei
Journal of Materials Chemistry A 2015 - vol. 3(Issue 4) pp:NaN1623-1623
Publication Date(Web):2014/11/18
DOI:10.1039/C4TA05212A
A GeO2/RGO composite was successfully fabricated via alternating deposition of graphene oxide (GO) and GeO2 on the surface of a Ni foam substrate using a facile dip-coating method cooperated with in situ hydrolysis of GeCl4. This material was directly used as a binder-free anode for LIBs and exhibited high reversible capacity (1716 mA h g−1 at 0.2 A g−1, 702 mA h g−1 at 16 A g−1), good cycling performance (1159 mA h g−1 at 1 A g−1 after 500 cycles) and excellent rate capability. In addition, a reversible capacity as high as 621 mA h g−1 can be retained when cycled to 500 cycles at a rate as high as 8 A g−1.
Co-reporter:Xin Liu, Zhiwei Li, Hailong Fei and Mingdeng Wei
Dalton Transactions 2015 - vol. 44(Issue 43) pp:NaN18869-18869
Publication Date(Web):2015/10/02
DOI:10.1039/C5DT03239C
A layer structured K-doped (NH4)2V3O8/graphene (K-NVG) was prepared via a hydrothermal route and then used as an anode material for sodium-ion batteries for the first time. The K-NVG nanosheets have a diameter in the range of 200–500 nm. The K-NVG electrode exhibited stable cycling and a good rate performance with a reversible capacity of 235.4 mA h g−1, which is much higher than the 90.5 mA h g−1 value of the (NH4)2V3O8/graphene electrode after 100 cycles at a current density of 100 mA g−1. Simultaneously, the retention rate was maintained at 82% even after 250 cycles at the current density of 300 mA g−1. Such good electrochemical properties may be attributed to the K-NVG's stable layered structure.
Co-reporter:Peixun Xiong, Guojin Zeng, Lingxing Zeng and Mingdeng Wei
Dalton Transactions 2015 - vol. 44(Issue 38) pp:NaN16751-16751
Publication Date(Web):2015/08/25
DOI:10.1039/C5DT03030G
In the present work, Prussian blue analogues, Mn[Fe(CN)6]0.6667·nH2O (Mn-PBA), were synthesized by a simple synthetic route and characterized by XRD, SEM, TEM, FTIR and TGA. When this material was firstly used as an anode for lithium-ion batteries, it exhibited a large capacity, good rate capability and cycling stability with a high Coulombic efficiency. For instance, a reversible capacity of 295.7 mA h g−1 can be achieved after 100 cycles at 200 mA g−1.
Co-reporter:Lingxing Zeng, Xiaoxia Huang, Cheng Zheng, Qingrong Qian, Qinghua Chen and Mingdeng Wei
Dalton Transactions 2015 - vol. 44(Issue 17) pp:NaN7972-7972
Publication Date(Web):2015/03/20
DOI:10.1039/C5DT00673B
Hierarchical LiZnVO4@C nanostructures composed of thin nanobelt aggregates were synthesized for the first time through an ethanol thermal and subsequent annealing route, and were investigated by X-ray diffraction (XRD), thermogravimetric analysis (TGA), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Furthermore, the synthesized hierarchical nanostructures were used as anode materials for Li-ion intercalation and exhibited a large reversible capacity, high rate performance, and excellent cycling stability. For instance, a high reversible capacity of 675 mA h g−1 was maintained after 60 cycles at a current density of 50 mA g−1. These results might be attributed to the following facts: (i) the hierarchical nanostructures could buffer the strain and volume changes during the cycling process; (ii) the thin nanobelts provide a shortened distance for Li-ion intercalation; (iii) the thin carbon layer on the surface of the nanobelts could provide a fast route for electron transportation, leading to an improved capacity and high rate performance.
Co-reporter:Qixin Deng, Mingdeng Wei, Xiaokun Ding, Lilong Jiang, Binghuo Ye and Kemei Wei
Chemical Communications 2008(Issue 31) pp:NaN3659-3659
Publication Date(Web):2008/06/13
DOI:10.1039/B802896F
Brookite-type TiO2nanotubes with crystalline multilayer walls have been synthesized for the first time via a simple hydrothermal route.
Co-reporter:Qixin Deng, Chaozhang Huang, Wei Xie, Jianping Zhang, Yiqiang Zhao, Zhensheng Hong, Aiying Pang and Mingdeng Wei
Chemical Communications 2011 - vol. 47(Issue 21) pp:NaN6155-6155
Publication Date(Web):2011/04/26
DOI:10.1039/C1CC10794A
Titanate nanosheets and nanotubes have first been introduced into cigarette filter, a great range of harmful compounds including tar, nicotine, ammonia, hydrogen cyanide, selected carbonyls and phenolic compounds can be reduced efficiently.
Co-reporter:Cheng Zheng, Minying Liu, Wenqiang Chen, Lingxing Zeng and Mingdeng Wei
Journal of Materials Chemistry A 2016 - vol. 4(Issue 35) pp:NaN13651-13651
Publication Date(Web):2016/08/09
DOI:10.1039/C6TA05029H
A composite of Se/CMK-3 was in situ synthesized for the first time via a carbon thermal reduction route by using ordered mesoporous carbon CMK-3 as a nanoreactor and reduction agent, and was then applied as an anode material for Li-ion intercalation. Owing to the fact that CMK-3 acts as a stable matrix for Se and facilitates electronic conductivity and ion transportation, the composite exhibited large reversible capacity, high rate performance and excellent long-term cycling stability. For instance, a reversible capacity of 770 mA h g−1 can be achieved after 100 cycles at 1C, and a capacity of 619 mA h g−1 was retained after 1000 cycles even at a rate as high as 2C.
