Co-reporter:Zhengjiao Liu, Pengqian Guo, Boli Liu, Wenhe Xie, Dequan Liu, Deyan He
Applied Surface Science 2017 Volume 396() pp:41-47
Publication Date(Web):28 February 2017
DOI:10.1016/j.apsusc.2016.11.045
Abstract
Silicon is the most promising anode material for the next-generation lithium-ion batteries (LIBs). However, the large volume change during lithiation/delithiation and low intrinsic conductivity hamper its electrochemical performance. Here we report a well-designed LIB anode in which carbon-coated Si nanoparticles/reduced graphene oxide (Si/rGO) multilayer was anchored to nanostructured current collector with stable mechanical support and rapid electron conduction. Furthermore, we improved the integral stability of the electrode through introducing amorphous carbon. The designed anode exhibits superior cyclability, its specific capacity remains above 800 mAh g−1 after 350 cycles at a current density of 2.0 A g−1. The excellent electrochemical performance can be attributed to the fact that the Si/rGO multilayer is reinforced by the nanostructured current collector and the formed amorphous carbon, which can maintain the structural and electrical integrities of the electrode.
Co-reporter:Boli Liu, Dan Li, Zhengjiao Liu, Lili Gu, Wenhe Xie, Qun Li, Pengqian Guo, Dequan Liu, Deyan He
Applied Surface Science 2017 Volume 394() pp:1-8
Publication Date(Web):1 February 2017
DOI:10.1016/j.apsusc.2016.10.108
Highlights
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The C-MnO/rGO composites were anchored on nickel foam by a facile vacuum filtration and a subsequent thermal treatment.
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The novel architecture of anodes effectively improved the electrochemical performance of lithium ion battery.
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The active MnO nanodendrites became smaller nanoparticles still wrapped in graphene sheets after cycles.
Co-reporter:Wenhe Xie, Lili Gu, Suyuan Li, Xiaoyi Hou, Boli Liu, Mengting Liu, Deyan He
Materials Letters 2017 Volume 189() pp:259-262
Publication Date(Web):15 February 2017
DOI:10.1016/j.matlet.2016.12.017
•Novel porous carbon nanofibers derived from polydopamine were fabricated.•The nanopores in our designed nanofibers are confined by the inner carbon walls and outer carbon shells.•The resultant carbon nanofiber electrodes display superhigh reversible capacity.Porous N-doped carbon nanofibers derived from polydopamine are fabricated by a facile carbonized technique and a subsequent template-removing process. Superior to the other porous carbon nanomaterials that voids are directly exposed in the electrolyte, the nanopores in our designed nanofibers are confined by the inner carbon walls and outer carbon shells. The prepared porous N-doped carbon nanofibers electrode shows high reversible capacities of 1324 mAh g−1 after 150 cycles at 0.2 A g−1 and 780 mAh g−1 after 500 cycles at 1 A g−1.
Co-reporter:Mengting Liu;Xia Deng;Yaodong Ma;Wenhe Xie;Xiaoyi Hou;Yujun Fu
Advanced Materials Interfaces 2017 Volume 4(Issue 19) pp:
Publication Date(Web):2017/10/01
DOI:10.1002/admi.201700553
AbstractIn a simple strategy of mild heat-assistant precipitation followed by annealing in air, hierarchical Co3O4 flower-like microspheres self-constructed by porous nanosheets are synthesized in bulk and tested as an anode material for advanced lithium-ion batteries (LIBs). Benefited from its high porosity and specific surface area as well as a necessary short activation, the as-prepared architecture shows an enhanced lithium storage performance of high capacity, long-life cycle, and ultrahigh rate capacity compared with the great majority of reported and commercial Co3O4 materials. Especially, it delivers a reversible capacity of 715 mAh g−1 after 1000 cycles under a current density of 1000 mA g−1 with a coulombic efficiency of more than 99%. When the electrode is laid aside for 5 d and recycled again, it can reach upward of 680 mAh g−1 for another 150 cycles. Such an impressive electrochemical performance indicates that the hierarchical Co3O4 flower-like microspheres can be a promising electrode material of advanced LIBs in future.
Co-reporter:Zhengjiao Liu;Shuai Bai;Boli Liu;Pengqian Guo;Mingzhi Lv;Dequan Liu
Journal of Materials Chemistry A 2017 vol. 5(Issue 25) pp:13168-13175
Publication Date(Web):2017/06/27
DOI:10.1039/C7TA03576D
Carbonized melamine formaldehyde foam has been modified with a thin titanium layer and then used as an inexpensive and lightweight current collector. By depositing a silicon film on the thin Ti layer modified carbon foam, a self-supported Si electrode was obtained for lithium-ion batteries (LIBs). The Ti/Si interface has been further strengthened by annealing treatment, which dramatically suppressed the electrode pulverization induced by the huge volume changes of silicon in cycles. The self-supported Si electrode displayed a high rechargeable specific capacity of 1296 mA h g−1 at a current density of 2.0 A g−1 and excellent cycling performance up to 1000 cycles. When the prepared Si electrode was paired with a casted LiCoO2 (LCO) electrode to design a Si/LCO full-cell LIB, it displayed a reversible charge/discharge capability in all 200 cycles. As a result of the lightweight carbon foam collector, the self-supported electrode assembly strategy and the high specific capacity of silicon, a high-energy density of 479.5 W h kg−1 was attained. The thin titanium layer modification can be applied to improve the contact interface between other carbonaceous current collectors and active materials with inferior electronic conductivity and large volume changes in cycles.
Co-reporter:Li Qiao;Li Qiao;Xiuwan Li;Xiaolei Sun;Hongwei Yue
Journal of Materials Science 2017 Volume 52( Issue 12) pp:6969-6975
Publication Date(Web):2017 June
DOI:10.1007/s10853-017-0929-5
Interconnected fullerene-like carbon nanofibers encapsulated with tin nanoparticles (Sn@FLCNFs) were synthesized by a facile and scalable electrospinning method using fullerene-like carbon nanoparticles and PVP as carbon sources. SEM and TEM revealed that Sn nanoparticles have been uniformly embedded into the nanofibers. The self-supported Sn@FLCNFs could be directly used as an anode of lithium-ion battery without adding any polymer and binder; it showed a high initial coulombic efficiency. A reversible capacity as high as 846 mA h g−1 remained after 100 cycles at a current density of 0.2 A g−1. When the current density was raised to 1 A g−1, the reversible capacity maintained 656 mA h g−1 after 300 cycles. The excellent electrochemical performance can be attributed to the formation of the efficient Li-ions diffusion paths and highly conductive cross-linked network in the Sn@FLCNFs electrode, and the interconnected carbon framework can prevent the Sn nanoparticles from pulverization and re-aggregation during cycles.
Co-reporter:Tinghui Yao;Xin Guo;Shengchun Qin;Fangyuan Xia;Qun Li;Yali Li
Nano-Micro Letters 2017 Volume 9( Issue 4) pp:
Publication Date(Web):2017 October
DOI:10.1007/s40820-017-0141-9
In this study, the effect of reduced graphene oxide (rGO) on interconnected Co3O4 nanosheets and the improved supercapacitive behaviors is reported. By optimizing the experimental parameters, we achieved a specific capacitance of ~1016.4 F g−1 for the Co3O4/rGO/NF (nickel foam) system at a current density of 1 A g−1. However, the Co3O4/NF structure without rGO only delivers a specific capacitance of ~520.0 F g−1 at the same current density. The stability test demonstrates that Co3O4/rGO/NF retains ~95.5% of the initial capacitance value even after 3000 charge–discharge cycles at a high current density of 7 A g−1. Further investigation reveals that capacitance improvement for the Co3O4/rGO/NF structure is mainly because of a higher specific surface area (~87.8 m2 g−1) and a more optimal mesoporous size (4–15 nm) compared to the corresponding values of 67.1 m2 g−1 and 6–25 nm, respectively, for the Co3O4/NF structure. rGO and the thinner Co3O4 nanosheets benefit from the strain relaxation during the charge and discharge processes, improving the cycling stability of Co3O4/rGO/NF.
Co-reporter:Xinghui Wang, Leimeng Sun, Xiaolei Sun, Xiuwan Li, Deyan He
Materials Research Bulletin 2017 Volume 96, Part 4(Volume 96, Part 4) pp:
Publication Date(Web):1 December 2017
DOI:10.1016/j.materresbull.2017.04.046
•Size-controllable porous NiO electrodes were prepared by a simple thermal oxidation route.•The prepared porous NiO electrodes exhibit high capacity and excellent rate capability and cycling stability.•The smaller nanopore and crystallite size are benefical to improve the electrochemical properties of the porous NiO electrodes.Size-controllable porous NiO electrodes were prepared by a simple and easily scalable thermal oxidation route and were evaluated as anode materials for lithium ion batteries. The nanopore size of the prepared electrodes can be obtained in the range from 20 to 80 nm by varying the thermal oxidation condition. Lithium storage performance measurement showed that porous NiO electrodes exhibit high capacity and excellent rate capability and cycling stability. Furthermore, it was shown that the smaller nanopore and crystallite size are beneficial to improve the electrochemical properties of the porous NiO electrodes.Download high-res image (246KB)Download full-size image
Co-reporter:Shuai Bai, Yaodong Ma, Xinyu Jiang, Qun Li, Zhibo Yang, Qiming Liu, Deyan He
Surfaces and Interfaces 2017 Volume 8(Volume 8) pp:
Publication Date(Web):1 September 2017
DOI:10.1016/j.surfin.2017.06.010
PEDOT-PSS coated nanostructured Ge anodes were prepared for lithium-ion batteries. The obtained binder-free electrodes show excellent electrochemical performance. The representative anode exhibits a reversible capacity of 640 mAh g−1 after 1000 cycles at a current density of 2 A g−1, which is much better than the nanostructured Ge anodes without PEDOT–PSS coating. The significantly enhanced cycle performance can be attributed to that the PEDOT-PSS coating highly facilitates the structural integrity of the electrode.
Co-reporter:Xiaoyi Hou, Shuai Bai, Song Xue, Xiaonan Shang, Yujun Fu, Deyan He
Journal of Alloys and Compounds 2017 Volume 711(Volume 711) pp:
Publication Date(Web):15 July 2017
DOI:10.1016/j.jallcom.2017.04.062
•Wrinkled-paper-like ZnCo2O4 nanoflakes have been prepared on conductive Ni foam.•The resultant electrode delivers ultrahigh-rate performance even at 25.6 A g−1.•A reversible capacity of 1138 mAh g−1 at a rate of 1 A g−1 was obtained after 500 cycles.Wrinkled-paper-like ZnCo2O4 nanoflakes were synthesized by a facile hydrothermal synthesis and a post-annealing treatment. As an anode for lithium-ion batteries, it exhibits high capacity, excellent cyclability and ultrahigh rate performance. A reversible capacity of 1138 mAh g−1 at 1 A g−1 was obtained after 500 cycles. After cycled at current densities from 0.2 to 25.6 A g−1, the reversible capacity can recover to 1089 mAh g−1 at 0.2 A g−1. It has been demonstrated that the wrinkled-paper-like ZnCo2O4 nanoflakes are promising for application as future energy storage units.Download high-res image (276KB)Download full-size image
Co-reporter:Pengqian Guo, Dequan Liu, Zhengjiao Liu, Xiaonan Shang, Qiming Liu, Deyan He
Electrochimica Acta 2017 Volume 256(Volume 256) pp:
Publication Date(Web):1 December 2017
DOI:10.1016/j.electacta.2017.10.003
•Dual functional MoS2/graphene interlayer was first used as an efficient polysulfide-trapping shield for lithium-sulfur batteries.•MoS2/graphene interlayer shows strong chemical interactions with LiPSs.•MoS2/graphene interlayer forms a 3D network to facilitate electron and ion transfer during the discharge-charge processes.•The resultant lithium-sulfur batteries exhibit a superior rate capacity and improved cycling capacity.A dual functional interlayer consisted of composited two-dimensional MoS2 and graphene has been developed as an efficient polysulfide barrier for lithium-sulfur batteries (LSBs). With such a configuration, LSBs show a superior rate capacity and improved cycling capacity. The excellent electrochemical performance can be attributed to the strong bonding interactions between the MoS2/graphene interlayer and the formed lithium polysulfides (LiPSs) as well as the good electrical conductivity of the MoS2/graphene composite. The MoS2/graphene interlayer can physically block LiPSs by the graphene nanosheets and chemically suppress the dissolution of LiPSs by the polar MoS2 nanoflowers. Such a dual functional interlayer further provides a good contact with the surface of the sulfur cathode, acts as an upper current collector and greatly improves the sulfur utilization and the rate capability of LSBs.
Co-reporter:Wenhe Xie, Lili Gu, Fangyuan Xia, Boli Liu, Xiaoyi Hou, Qi Wang, Dequan Liu, Deyan He
Journal of Power Sources 2016 Volume 327() pp:21-28
Publication Date(Web):30 September 2016
DOI:10.1016/j.jpowsour.2016.07.030
•Novel SnO2/voids@C nanofiber with voids was designed.•The SnO2 can freely expand and hardly aggregate.•The resultant electrodes display high initial coulombic efficiency.•The conversion of SnO2 to Sn is reversible for both half and full cells.Despite their potential application in lithium-ion battery electrodes, one apparent disadvantage for SnO2-based materials is that the electrodes suffer low coulombic efficiency especially for the initial cycle, which originates from the irreversible conversion of SnO2 to Sn, the formation of solid electrolyte interphase and the other possible side reactions. Here we design a novel nanofiber structure in which SnO2 nanoparticles are well separated and confined by inner porous carbon framework and then hooped by outer carbon shell. The resultant SnO2/voids@C nanofibers electrode displays not only a high reversible capacity of 986 mAh g−1 at 200 mA g−1 after 200 cycles, but also a high initial coulombic efficiency of 73.5%. It has been shown that such a rational design can efficiently reduce the side reactions and promote the reversible conversion of Sn to SnO2 for both half and full cells.
Co-reporter:Suyuan Li, Wenhe Xie, Lili Gu, Zhengjiao Liu, Xiaoyi Hou, Boli Liu, Qi Wang, Deyan He
Electrochimica Acta 2016 Volume 193() pp:246-252
Publication Date(Web):1 March 2016
DOI:10.1016/j.electacta.2016.02.074
Binder-free electrodes of Si nanoparticles@reducedgrapheneoxidesheets(Si@rGO) for lithium ion batteries were facilely fabricated by scraping the mixture of commercial Si powder, graphene oxide and poly(vinyl pyrrolidone) (PVP) onto nickel foam and following a heat treatment. It was shown that the Si@rGO electrode performs an excellent electrochemical behavior. Even at a current density as high as 4 A/g, a reversible capacity of 792 mAh/g was obtained after 100 cycles. A small amount of PVP additive plays important roles, it not only increases the viscosity of the mixture paint in the coating process, but also improves the conductivity of the overall electrode after carbonization.
Co-reporter:Lili Gu, Wenhe Xie, Shuai Bai, Boli Liu, Song Xue, Qun Li, Deyan He
Applied Surface Science 2016 Volume 368() pp:298-302
Publication Date(Web):15 April 2016
DOI:10.1016/j.apsusc.2016.01.270
Highlights
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The NiO nanocone arrays are fabricated by a simple hydrothermal synthesis and a subsequent thermal oxidation in air.
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The binder-free NiO nanocone array electrode shows excellent rate capacity.
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The cycled NiO electrode well retains its three-dimensional morphology of nanocone array.
Co-reporter:Na Feng, Xiaolei Sun, Hongwei Yue and Deyan He
RSC Advances 2016 vol. 6(Issue 76) pp:72008-72014
Publication Date(Web):25 Jul 2016
DOI:10.1039/C6RA12846G
Novel hierarchical Ni/NiO hybrid nanospheres were fabricated by a simple solvothermal synthesis method followed by thermal oxidation. The hybrid nanospheres are uniform-sized and composed of tiny Ni embedded NiO nanoparticles. Galvanostatic battery tests show that the corresponding electrode can deliver a high reversible capacity of 712 mA h g−1 for the second discharge and a capacity of 825 mA h g−1 was obtained after 132 cycles at a rate of 0.2C. Good rate performance was achieved even when the rate is as high as 12C with a high capacity of 453 mA h g−1, and a capacity of 800 mA h g−1 was retained when it returned to 0.2C after 300 cycles. The excellent cycling stability and rate performance are derived from the special nanostructural characteristics of the prepared hybrid nanospheres, indicating that they are a promising anode material for high-performance lithium-ion batteries.
Co-reporter:Yunxian Zheng, Li Qiao, Jun Tang, Zhibo Yang, Hongwei Yue and Deyan He
RSC Advances 2015 vol. 5(Issue 45) pp:36117-36121
Publication Date(Web):14 Apr 2015
DOI:10.1039/C5RA04447B
Interconnected porous Co3O4 nanoflakes were prepared on nickel foam by a simple electrochemical deposition combined with a subsequent heat treatment. The featured nanoflakes consisted of interconnected primary nanoparticles and nanopores resulting in a large specific surface area. As an anode material of lithium ion batteries, the as-prepared samples exhibited superior cyclic performance and excellent rate capacity. The discharge capacity remained at 1211 mA h g−1 after 100 cycles at a current density of 1 A g−1. Notably, after cycling at various current densities up to 5 A g−1, the capacity recovered to 1266 mA h g−1 at 0.1 A g−1.
Co-reporter:Xiaonan Shang, Xiuwan Li, Hongwei Yue, Song Xue, Zhengjiao Liu, Xiaoyi Hou, Deyan He
Materials Letters 2015 Volume 157() pp:7-10
Publication Date(Web):15 October 2015
DOI:10.1016/j.matlet.2015.05.097
•Interconnected porous NiO@MnO2 nanosheets are synthesized by hydrothermal route.•The core@shell structure makes use of the interaction between MnO2 and NiO.•The reversible capacity is as high as 1000 mAh g−1 after 160 cycles.•The prepared electrode exhibits excellent rate capability and cycling stability.Interconnected porous NiO@MnO2 nanosheets are synthesized on nickel foam by hydrothermal method. As an anode of lithium-ion batteries (LIBs), such a architecture could shorten the diffusion distance of lithium ions and largen the contact area between the active material and electrolyte. It displays a high capacity of 1000 mAh g−1 after 160 cycles at a rate of 1.0 C. More importantly, the electrode exhibits an excellent rate performance, it delivers a capacity about 787 mAh g−1 at 5.0 C. The superior lithium storage properties suggest that the interconnected porous NiO@MnO2 nanosheets can function as a promising anode material for high-performance LIBs.
Co-reporter:Shumei Lin, Zhibo Yang, Hongwei Yue, Deyan He
Materials Letters 2015 Volume 158() pp:9-12
Publication Date(Web):1 November 2015
DOI:10.1016/j.matlet.2015.05.051
•Porous WS2 film was deposited via a magnetron sputtering method.•Ridge-like Ni architecture coated Cu foil was used as current collector.•The WS2/Ni/Cu exhibit excellent electrochemical performance as anode for LIBs.Porous WS2 films have been deposited on ridge-like Ni coated Cu foils using a magnetron sputtering system, their morphology and structure were characterized by field-emission scanning electron microscope, high-resolution transmission electron microscopy and micro-Raman spectrometer. Electrochemical evaluation showed that, as negative electrode for lithium-ion batteries, the representative ridge-like Ni supported WS2 film electrode performs a high reversible capacity and excellent rate capability which can deliver a discharge capacity as high as 1180 mA h g−1 after 100 cycles at 100 mA g−1. The capacities almost remain the same as the current density increases from 100 to 800 mA g−1. Even at 1600 mA g−1, the electrode can deliver a capacity as high as 986 mA h g−1.
Co-reporter:Suyuan Li, Qi Wang, Wenhe Xie, Song Xue, Xiaoyi Hou, Deyan He
Materials Letters 2015 Volume 158() pp:244-247
Publication Date(Web):1 November 2015
DOI:10.1016/j.matlet.2015.05.168
•Carbon-coated SnO2 nanotube networks were fabricated by a simple dip-coating process and subsequent CVD growth.•The as-prepared material worked as a binder-free anode for lithium ion battery.•It delivered a reversible capacity of 653 mAh g−1 after 50 cycles at a current density of 400 mA g−1.Carbon-coated SnO2 nanotube networks were fabricated by a simple dip-coating process and subsequent CVD growth. The as-prepared material, worked as a binder-free anode for lithium ion battery, delivers a reversible capacity of 653 mAh g−1 after 50 cycles at a current density of 400 mA g−1. The enhanced electrochemical performance can be ascribed to the following factors: (1) The network nanostructure can accommodate the volume changes of the SnO2 nanoparticles. (2) The porous walls of the prepared nanotubes increase the electrode–electrolyte contact area, shorten the distance of diffusion and provide more reaction sites for lithium ions. (3) The carbon coating increases the conductivity and hinders the aggregation of the SnO2 nanoparticles during the insertion/extraction processes of lithium ions.
Co-reporter:Yanli Qin, Fei Li, Xiaobing Bai, Xiaolei Sun, Dequan Liu, Deyan He
Materials Letters 2015 Volume 138() pp:104-106
Publication Date(Web):1 January 2015
DOI:10.1016/j.matlet.2014.09.101
•Electron irradiation is firstly used to prepare Si film anode for lithium-ion battery.•A novel Si film with defect-rich Si nanocrystals embedded in amorphous matrix is obtained.•The irradiated Si film exhibits improved cycle performance.A novel Si film with Si nanocrystals embedded in amorphous Si matrix was grown on Cu foil via an inductively coupled plasma-enhanced chemical vapor deposition and subsequent electron beam irradiation. The Si nanocrystals show spherical morphology with rich defects and the mean size is about 6 nm. The electrochemical performance of the obtained Si as anode for lithium ion batteries was studied via conventional charge/discharge test, which shows distinct improvement on cycle performance compared with that of amorphous Si obtained without electron beam irradiation.
Co-reporter:Xiuwan Li, Zhibo Yang, Yujun Fu, Li Qiao, Dan Li, Hongwei Yue, and Deyan He
ACS Nano 2015 Volume 9(Issue 2) pp:1858
Publication Date(Web):January 28, 2015
DOI:10.1021/nn506760p
Germanium is a highly promising anode material for lithium-ion batteries as a consequence of its large theoretical specific capacity, good electrical conductivity, and fast lithium ion diffusivity. In this work, Co3O4 nanowire array fabricated on nickel foam was designed as a nanostructured current collector for Ge anode. By limiting the voltage cutoff window in an appropriate range, the obtained Ge anode exhibits excellent lithium storage performance in half- and full-cells, which can be mainly attributed to the designed nanostructured current collector with good conductivity, enough buffering space for the volume change, and shortened ionic transport length. More importantly, the assembled Ge/LiCoO2 full-cell shows a high energy density of 475 Wh/kg and a high power density of 6587 W/kg. A high capacity of 1184 mA h g–1 for Ge anode was maintained at a current density of 5000 mA g–1 after 150 cycles.Keywords: anode material; Co3O4 nanowires; full-cell; germanium coating; nanostructured current collector;
Co-reporter:Hongwei Yue, Fei Li, Zhibo Yang, Xiuwan Li, Shumei Lin and Deyan He
Journal of Materials Chemistry A 2014 vol. 2(Issue 41) pp:17352-17358
Publication Date(Web):28 Aug 2014
DOI:10.1039/C4TA04095C
Carbon nanofibers (CNFs) were deposited on Cu foam by a floating catalyst method, and a Mn3O4 layer was then coated onto the deposited CNFs via a hydrothermal process based on the redox reaction of carbon and potassium permanganate. The obtained architecture of Mn3O4-coated CNFs (CNFs@Mn3O4) on Cu foam was directly used as an anode for lithium-ion batteries without using any binder or conducting additive. The anode showed high reversible capacity, good cycle stability and superior rate capability. A reversible capacity of up to 1210.4 mA h g−1 was obtained after 50 cycles at a current density of 100 mA g−1. When the current density increased to 5000 mA g−1, it could deliver a capacity of more than 300 mA h g−1. The excellent electrochemical performance could be attributed to the unique morphology of the CNFs@Mn3O4 nanocomposites, which can buffer the volume change, decrease the contact resistance, shorten the ionic diffusion path and make the electron transport more efficient.
Co-reporter:Fei Li, Yanli Qin, Hongwei Yue, Zhibo Yang, Xiuwan Li and Deyan He
Journal of Materials Chemistry A 2014 vol. 2(Issue 24) pp:9156-9163
Publication Date(Web):25 Mar 2014
DOI:10.1039/C4TA01171F
NiO layers were coated in situ onto Ni-silicide nanowires by an oxidation in air. The surface of the nanowires had been previously roughened by etching in HF solution. It is found that the roughened surface is very helpful to enhance the in situ coating ability of NiO on the nanowires. When the resulting samples were used as anodes for lithium-ion batteries, a high reversible capacity of 1.28 mA h cm−2 was obtained for the surface-roughened nanowires with 30 min HF-treatment, which is 3 times higher than that of the nanowires without HF-treatment. The current density can reach up to 2.15 mA cm−2 for the 60 min HF-treated and then oxidized nanowires, while the capacity is maintained at as high as 0.52 mA h cm−2. The improved cyclic performance could be attributed to the roughened surface of the nanowires, which enhanced the coating ability of the NiO layers, and provided a porous structure that is of benefit to increase the area of the electrode/electrolyte interface for the adsorption of ions. In addition, the Ni-silicide nanowires can improve the electrode conductivity and act as a stable support for the NiO coating layers during cycling, making a positive contribution to the electrochemical performance.
Co-reporter:Suyuan Li, Wenhe Xie, Suiyan Wang, Xinyu Jiang, Shanglong Peng and Deyan He
Journal of Materials Chemistry A 2014 vol. 2(Issue 40) pp:17139-17145
Publication Date(Web):26 Aug 2014
DOI:10.1039/C4TA03907F
The reduced graphene oxide/SnO2 (rGO/SnO2) composite was facilely synthesized via a modified colloidal coagulation method and a subsequent reduction. As an anode for lithium ion batteries, it delivers a high reversible capacity of 795 mA h g−1 in the 600th cycle at a current density of 1000 mA g−1. The excellent electrochemical performances are mainly due to its morphology stability and the reversible reaction between the formed Li2O and Sn to yield SnO2, as confirmed by XPS and TEM characterization after 200 cycles.
Co-reporter:Xiuwan Li, Zhibo Yang, Shumei Lin, Dan Li, Hongwei Yue, Xiaonan Shang, Yujun Fu and Deyan He
Journal of Materials Chemistry A 2014 vol. 2(Issue 36) pp:14817-14821
Publication Date(Web):23 Jul 2014
DOI:10.1039/C4TA03304C
Silicon is considered as a promising candidate for next-generation lithium-ion battery anodes. However, severe capacity fading caused by volume change during Li-ion insertion and extraction hinders its practical application. In this work, gold granular film and polyvinylidene fluoride coating are sequentially prepared on the deposited Si film to solve the aforementioned problem.
Co-reporter:Jun Tang, Dequan Liu, Yunxian Zheng, Xiuwan Li, Xinghui Wang and Deyan He
Journal of Materials Chemistry A 2014 vol. 2(Issue 8) pp:2585-2591
Publication Date(Web):20 Nov 2013
DOI:10.1039/C3TA14042C
Interconnected α-Co(OH)2 nanosheets with various proportions of substituted Zn were electrochemically deposited on nickel foam substrates. The architectures were used directly as electrodes for supercapacitors, which exhibited excellent pseudocapacitive performance. Compared with the pure α-Co(OH)2 nanosheet electrode with a capacitance loss of 17.5% after 2000 cycles, the 9.7 at.% Zn-substituted α-Co(OH)2 electrode showed stabilized capacitance with a loss of 1.1%, and the electrode with 21.1 at.% Zn substitution demonstrated a high cycling stability with a capacitance loss of only 0.6% from 652 F g−1 after 2000 cycles. The enhanced cycling stability is attributed to the stabilization of the structure of the materials by the incorporation of inactive Zn2+ ions.
Co-reporter:Dan Li, Xiuwan Li, Suiyan Wang, Yunxian Zheng, Li Qiao, and Deyan He
ACS Applied Materials & Interfaces 2014 Volume 6(Issue 1) pp:648
Publication Date(Web):December 9, 2013
DOI:10.1021/am404756h
Carbon-wrapped Fe3O4 nanoparticle films on nickel foam were simply prepared by a hydrothermal synthesis with sucrose as a precursor of subsequent carbonization. The as-prepared samples were directly used as binder-free anodes for lithium-ion batteries which exhibited enhanced rate performance and excellent cyclability. A reversible capacity of 543 mA h g–1 was delivered at a current density as high as 10 C after more than 2000 cycles. The superior electrochemical performance can be attributed to the formation of a thin carbon layer which constructs a 3D network structure enwrapping the nanosized Fe3O4 particles. Such an architecture can facilitate the electron transfer and accommodate the volume change of the active materials during discharge/charge cycling.Keywords: carbon-wrapping; enhanced rate performance; Fe3O4 nanoparticles; hydrothermal process; lithium ion battery;
Co-reporter:Wenhe Xie, Suyuan Li, Suiyan Wang, Song Xue, Zhengjiao Liu, Xinyu Jiang, and Deyan He
ACS Applied Materials & Interfaces 2014 Volume 6(Issue 22) pp:20334
Publication Date(Web):November 7, 2014
DOI:10.1021/am505829v
N-doped amorphous carbon coated Fe3O4/SnO2 coaxial nanofibers were prepared via a facile approach. The core composite nanofibers were first made by electrospinning technology, then the shells were conformally coated using the chemical bath deposition and subsequent carbonization with polydopamine as a carbon source. When applied as a binder-free self-supported anode for lithium ion batteries, the coaxial nanofibers displayed an enhanced electrochemical storage capacity and excellent rate performance. The morphology of the interwoven nanofibers was maintained even after the rate cycle test. The superior electrochemical performance originates in the structural stability of the N-doped amorphous carbon shells formed by carbonizing polydopamine.Keywords: anode; carbonized polydopamine; composite nanofibers; Fe3O4/SnO2; N-doped amorphous carbon coating
Co-reporter:Dan Li, Xiuwan Li, Xiaoyi Hou, Xiaolei Sun, Boli Liu and Deyan He
Chemical Communications 2014 vol. 50(Issue 66) pp:9361-9364
Publication Date(Web):04 Jun 2014
DOI:10.1039/C4CC01311E
A Ni3S2 nanotube array has been synthesized on Ni foam using a template-free hydrothermal method. The Ni foam acts as both the reactant and support. The resulting architecture as an electrode for lithium ion batteries benefits from the unique morphology and exhibits excellent electrochemical performance with high capacity, long cycle life and superior rate capability.
Co-reporter:Fei Li, Hongwei Yue, Zhibo Yang, Xiuwan Li, Yanli Qin, Deyan He
Materials Letters 2014 Volume 128() pp:132-135
Publication Date(Web):1 August 2014
DOI:10.1016/j.matlet.2014.04.114
●High-flexibility free-standing graphene foams were prepared by CVD.●Light-weight graphene foam supported Si film anode was obtained.●The graphene foam supporting Si film anode shows high areal capacities.Silicon film was deposited onto free-standing graphene foam by chemical vapor deposition. The resultant samples showed high flexibility and were used as anodes for lithium-ion batteries without using any binder and additive. High reversible areal capacity of 1.4 mAh cm−2 was obtained at a current density of 0.22 mA cm−2, which corresponds to a gravimetric capacity as high as 620 mAh g−1 by considering the mass of the whole electrode. The improved electrochemical performance can be attributed to the unique hollow structure of the graphene foam which could provide stable support to the deposited Si film, and accommodate the volume changes to relieve strain-induced cracks of Si during cycling.
Co-reporter:Suyuan Li, Hongwei Yue, Qi Wang, Wenhe Xie, Deyan He
Materials Letters 2014 Volume 116() pp:271-274
Publication Date(Web):1 February 2014
DOI:10.1016/j.matlet.2013.11.015
•3D C/SnOx/C networks were prepared by a simple dip-coating process and subsequent CVD growth.•The product could work as a binder-free anode electrode.•The product has an excellent cyclic performance.3D networks consisted of C/SnOx/C hybrid nanofibers were prepared by a simple dip-coating process and subsequent CVD growth. The as-prepared material, worked as a binder-free anode electrode, delivered a reversible capacity of 512 mA h g−1 after 200 cycles at a current density of 200 mA g−1. The improved electrochemical performance can be ascribed to the morphological stability and the low resistance of the nanofibers with the CVD carbon skin. Furthermore, the embedded and de-aggregated SnOx nanoparticles in the carbon matrix provide large numbers of reaction sites for lithium ions. The results imply that 3D C/SnOx/C network nanocomposites have potential application in high-performance lithium ion batteries.
Co-reporter:Zhiwei Wei, Xiucheng Wei, Suiyan Wang, Deyan He
Materials Letters 2014 Volume 118() pp:107-110
Publication Date(Web):1 March 2014
DOI:10.1016/j.matlet.2013.12.051
•Heterophase junction material of α-Fe2O3/γ-Fe2O3 nanorods has been successfully prepared by a facile thermal decomposition and redox method.•The material exhibits a remarkably enhanced visible-light photocatalytic activity than the single-phase α-Fe2O3 or γ-Fe2O3 nanorods owing to its unique heterophase junctions.•The γ-Fe2O3 is of magnetism which facilitates the practical application of photocatalysts.Magnetic heterophase photocatalyst of α-Fe2O3/γ-Fe2O3 nanorods was prepared by a facile thermal decomposition and redox method. The nanorods were about 100 nm in length and 20 nm in diameter, and well-structured heterophase junctions were formed between α-Fe2O3 and γ-Fe2O3. Visible-light induced photodegradation of model dye rhodamine B was investigated by using the as-prepared α-Fe2O3/γ-Fe2O3 nanorods. The material exhibits a remarkably enhanced visible-light photocatalytic activity than the single-phase α-Fe2O3 or γ-Fe2O3 owing to its well-structured interfaces and suitable band configuration. The existence of magnetic γ-Fe2O3 facilitates the practical application of photocatalysts.
Co-reporter:Zhibo Yang, Desheng Wang, Fei Li, Hongwei Yue, Dequan Liu, Xiuwan Li, Li Qiao, Deyan He
Materials Letters 2014 Volume 117() pp:58-61
Publication Date(Web):15 February 2014
DOI:10.1016/j.matlet.2013.12.001
Co-reporter:Zhibo Yang, Shuai Bai, Hongwei Yue, Xiuwan Li, Dequan Liu, Shumei Lin, Fei Li, Deyan He
Materials Letters 2014 Volume 136() pp:107-110
Publication Date(Web):1 December 2014
DOI:10.1016/j.matlet.2014.08.034
•CuO nanorod network was prepared by a high-efficiency and scalable method.•Amorphous Ge was used as anode of Li-ion batteries for high power applications.•The Ge anode shows excellent rate capability and superior cyclability at high rates.•The CuO nanorod network could act as an electronic-conductor for many other anodes.Lithiated-CuO nanorods were used as a nanostructured electronic-conductor of the current-collector for Ge anode to improve the performance of lithium-ion batteries. By limiting the voltage cut-off window in a range which could avoid the discharge–charge plateaus of CuO after the initial discharge, the lithiated-CuO nanorods can act as an electronic-conductor. The obtained Ge anode exhibits an excellent rate capability and superior cyclability. At a current-density of 1 A/g, the anode presents a capacity retention of above 95% even after 100 cycles. The anode also presents a stable rate performance even at a current-density as high as 10 A/g. The enhanced performance can be mainly ascribed to the lithiated-CuO nanorods which could result in a nanocable structure that offers short electron/lithium-ion transport path, enough buffering space for the huge volume change of Ge coating and excellent electrical contact between the Ge coating and the current-collector.
Co-reporter:Xinghui Wang, Yu Fan, Rahmat Agung Susantyoko, Qizhen Xiao, Leimeng Sun, Deyan He, Qing Zhang
Nano Energy 2014 Volume 5() pp:91-96
Publication Date(Web):April 2014
DOI:10.1016/j.nanoen.2014.02.005
•The thick mesoporous Co3O4 nanosheet networks were fabricated on Ni foam by a simple method.•The prepared electrode exhibits both high specific capacity (1058 mAh g−1) and high area capacity (4.39 mAh cm−2).•The prepared electrode exhibits excellent rate capability and cycling stability.An advanced electrode for high areal capacity Li ion battery anode has been designed by growing ultra thick mesoporous Co3O4 nanosheet networks on Ni foam. This noval architecture consists of mesoporous Co3O4 nanosheets, which are interconnected with each other to form macropores. Benefiting from the favorable macro/meso-porous structures as well as the large mass loading of the synthesized Co3O4 on three dimensional foam, this unique electrode exhibits an areal capacity as high as 4.39 mAh cm−2 and excellent rate capability and cycling stability.An advanced electrode for high areal capacity Li ion battery anode has been designed by growing thick mesoporous Co3O4 nanosheet networks on Ni foam.
Co-reporter:Yali Li, Qiang Chen, Deyan He, Junshuai Li
Nano Energy 2014 Volume 7() pp:10-24
Publication Date(Web):July 2014
DOI:10.1016/j.nanoen.2014.04.015
•A comprehensive review on recent developments regarding boththeoretical investigation and experimental reports for Si micro/nano-wire array-based solar cells are presented.•An easily used explanationto illustrate optical behaviors in Si micro/nano-wire arrays is concluded, which is also applicable to other subwavelength structures.•Suggested device parameters including geometrical parameters, electrical parameters and issues regarding high quality wire preparation are summarized.•Several representative advanced solar cells employing Si micro/nano-wire arrays as a platformare introduced, such as 3D Si thin film solar cells.Radial pn junction Si micro/nano-wire arrays exhibit unique optical and electrical characteristics for building photovoltaic devices with high performance-to-cost ratios over traditional planar junction bulk Si structures. Through optimizing the structural parameters, such as wire diameter and array periodicity, antireflection even superior to the optimized antireflective coatings can be realized. In the meantime, excellent light confinement is easily achievable for Si micro/nano-wire arrays using much less materials compared to their bulk Si counterparts. From the electrical aspect, the radial pn junction configuration formed around the wires significantly reduces the minority carrier collection length along the radial direction, providing outstanding tolerance to material qualities. Owing to these charming properties, radial junction Si micro/nano-wire array-based solar cells have been attracting extensive attention. The power conversion efficiency has also made huge progress from <1% to the present >12% in less than 10 years. With cell performance improvement, the number of research papers regarding theoretical understanding and optimization of the optical and electrical processes, experimental reports of the related solar cells has also surged, also including review papers. Accordingly, in this paper we are focusing on the recent progress, following a brief but systematic introduction to the related topic. Then the issues needing to be addressed for further improving the optical and electrical structures and cell performance are summarized. Following that, several other advanced solar cells employing Si micro/nano-wire arrays as a platform are introduced.
Co-reporter:YingQi Liu;XiuWan Li;ZhiWei Wei;LiPing Zhang
Science China Technological Sciences 2014 Volume 57( Issue 6) pp:1077-1080
Publication Date(Web):2014 June
DOI:10.1007/s11431-014-5468-6
Tubular nanocomposite with interconnected MnO2 nanoflakes coated on MWCNTs (MWCNTs@MnO2) was fabricated by an aqueous solution method at 80°C. Scanning electron microscopy, X-ray diffraction and galvanostatic charge-discharge tests were used to characterize the structures and electrochemical performances of the as-prepared nanocomposite. The capacity reaches 1233.6 mA h g−1 at a current density of 100 mA g−1 for the first discharge, and it can still maintain a capacity of 633.1 mA h g−1 after 100 charge-discharge cycles. The results show that MWCNTs with good electrical conductivity as anchors of MnO2 can provide fast electron transport channels for MnO2 in the electrochemical reactions, and the as-prepared MWCNTs@MnO2 nanocomposite is a potential anode material for lithium ion batteries.
Co-reporter:Hongwei Yue, Fei Li, Zhibo Yang, Jun Tang, Xiuwan Li, Deyan He
Materials Letters 2014 120() pp: 39-42
Publication Date(Web):
DOI:10.1016/j.matlet.2014.01.049
Co-reporter:Li Qiao, Xinghui Wang, Li Qiao, Xiaolei Sun, Xiuwan Li, Yunxian Zheng and Deyan He
Nanoscale 2013 vol. 5(Issue 7) pp:3037-3042
Publication Date(Web):07 Feb 2013
DOI:10.1039/C3NR34103H
Porous NiO–ZnO hybrid nanofibers were prepared by a single-nozzle electrospinning technique combined with subsequent heating treatment. The resultant nanofibers are composed of interconnected primary nanocrystals and numerous nanopores with heterostructures between NiO and ZnO. Such characteristics of the structure can lead to excellent electrochemical performances when the nanofiber was evaluated as an anode material for lithium-ion batteries. The porous NiO–ZnO nanofiber electrode delivers a high discharge capacity of 949 mA h g−1 after 120 cycles at 0.2 A g−1, and maintains around 707 mA h g−1 at a current density as high as 3.2 A g−1. Even after cycling at high rates, the electrode still retains a high discharge capacity of up to 1185 mA h g−1 at 0.2 A g−1.
Co-reporter:Dequan Liu, Zhibo Yang, Peng Wang, Fei Li, Desheng Wang and Deyan He
Nanoscale 2013 vol. 5(Issue 5) pp:1917-1921
Publication Date(Web):04 Jan 2013
DOI:10.1039/C2NR33383J
Three-dimensional (3D) nanoporous architectures can provide efficient and rapid pathways for Li-ion and electron transport as well as short solid-state diffusion lengths in lithium ion batteries (LIBs). In this work, 3D nanoporous copper-supported cuprous oxide was successfully fabricated by low-cost selective etching of an electron-beam melted Cu50Al50 alloy and subsequent in situ thermal oxidation. The architecture was used as an anode in lithium ion batteries. In the first cycle, the sample delivered an extremely high lithium storage capacity of about 2.35 mA h cm−2. A high reversible capacity of 1.45 mA h cm−2 was achieved after 120 cycles. This work develops a promising approach to building reliable 3D nanostructured electrodes for high-performance lithium ion batteries.
Co-reporter:Yujun Fu, Zhibo Yang, Xiuwan Li, Xinghui Wang, Dequan Liu, Duokai Hu, Li Qiao and Deyan He
Journal of Materials Chemistry A 2013 vol. 1(Issue 34) pp:10002-10007
Publication Date(Web):21 Jun 2013
DOI:10.1039/C3TA11753G
3D interconnected network Ni nanofoams with large surface area were fabricated by a template-free approach. Their pore size and skeleton diameter are 150–350 nm and 200–300 nm, respectively. The homogeneous foaming structure and the metallic ductility of the Ni nanofoams make them suitable to be used as nanostructured current collectors. The Ni/NiO nanostructures were prepared by in situ thermal oxidation of the obtained Ni nanofoams. As anodes of lithium ion batteries, the Ni/NiO nanofoam electrodes deliver excellent cycling stability, superior rate capability, and high areal capacity. A high reversible capacity of 835 mA h g−1, which corresponds to an areal capacity of 2.1 mA h cm−2, was obtained after 200 cycles at a current rate of 0.5 C (1 C = 718 mA g−1). The Ni nanofoams exhibit an excellent electrochemical stability in electrolytes and are compatible with various electrochemically active materials as potential nanostructured current collectors for high-performance energy storage devices. Moreover, the preparation approach of the Ni nanofoams is facile, cost-effective, and can be used for large-scale production.
Co-reporter:Xiuwan Li, Li Qiao, Dan Li, Xinghui Wang, Wenhe Xie and Deyan He
Journal of Materials Chemistry A 2013 vol. 1(Issue 21) pp:6400-6406
Publication Date(Web):22 Mar 2013
DOI:10.1039/C3TA10821J
Three-dimensional network structured α-Fe2O3 was prepared by a facile chemical corrosion of a stainless steel plate followed by thermal oxidation. When the architecture was directly used as an electrode for lithium ion batteries (LIBs), a high reversible capacity of 858.2 mA h g−1 was obtained at a current density of 200 mA g−1 for the 2nd discharge. Especially, it retained a capacity of 1105.6 mA h g−1 at the 100th discharge–charge cycle. The mechanism behind the capacity increase with cycling has been investigated based on the capacity changes in different voltage regions. After cycling with various current densities, it can deliver a capacity of 520.0 mA h g−1 at a current density as high as 5000 mA g−1, indicating that the electrode prepared by such a simple route can be a promising candidate for high-power LIBs.
Co-reporter:Xinghui Wang, Li Qiao, Xiaolei Sun, Xiuwan Li, Duokai Hu, Qing Zhang and Deyan He
Journal of Materials Chemistry A 2013 vol. 1(Issue 13) pp:4173-4176
Publication Date(Web):08 Feb 2013
DOI:10.1039/C3TA01640D
Mesoporous NiO nanosheet networks with a thickness of more than 5 μm were fabricated on Ni foam for application as an electrode in Li ion batteries. Benefiting from the favorable macro/meso-porous structures as well as the great loading of the synthesized NiO, the electrode exhibits high capacity and excellent rate capability.
Co-reporter:Li Qiao, Xiaolei Sun, Zhibo Yang, Xinghui Wang, Qi Wang, Deyan He
Carbon 2013 Volume 54() pp:29-35
Publication Date(Web):April 2013
DOI:10.1016/j.carbon.2012.10.066
Fullerene-like carbon (FLC) nanoparticles were prepared by depositing soot of burning castor oil. FLC core/nano-crystalline silicon (nc-Si) shell nanofibers with network structures have been fabricated by electrospinning and plasma enhanced chemical vapor deposition techniques. The morphologies and structures of the materials were characterized using scanning electron microscopy, transmission electron microscopy, and micro-Raman spectroscopy. It was demonstrated that the FLC core/nc-Si shell nanofibers on nickel foam can be used as electrode for lithium-ion batteries without adding any binding or conducting additives. High reversible specific capacity of 1164 mA h g−1 is retained after 50 discharge/charge cycles at a constant current density of 100 mA g−1. The electrode delivers prolonged cycle life and enhanced rate capability compared to pristine nc-Si film. The improved electrochemical performance could be attributed to that the FLC core provides facile strain relaxation to accommodate the large Si volume expansion and shrinkage during lithium-ion insertion and extraction.
Co-reporter:Na Feng, Duokai Hu, Peng Wang, Xiaolei Sun, Xiuwan Li and Deyan He
Physical Chemistry Chemical Physics 2013 vol. 15(Issue 24) pp:9924-9930
Publication Date(Web):23 Apr 2013
DOI:10.1039/C3CP50615K
We report a facile and reproducible synthesis of nanostructured Ni3S2 films by a hydrothermal route with Ni foam as the precursor reactant and substrate. The synthetic mechanism was examined by investigating the dependence of the films' crystal morphologies on the hydrothermal duration, and uniform nanostructured Ni3S2 films with a porous carpet-like morphology were synthesized on the substrates. The architectures were used as cathodes for lithium ion batteries (LIBs), and their electrochemical performances were evaluated as a function of the film thickness. The first discharge and charge capacities were 596 and 466 mA h g−1 for the electrode with an optimal film thickness and a higher reversible capacity of 421 mA h g−1 was obtained after 60 cycles at a current density of 50 mA g−1. The simplicity of the synthetic methodology and the better electrochemical performance make the synthesized Ni3S2 films a promising cathode material for next-generation LIBs.
Co-reporter:Fei Li, Hongwei Yue, Peng Wang, Zhibo Yang, Desheng Wang, Dequan Liu, Li Qiao and Deyan He
CrystEngComm 2013 vol. 15(Issue 36) pp:7298-7306
Publication Date(Web):12 Jul 2013
DOI:10.1039/C3CE40651B
Crystalline Ni3Si2 nanostructures were grown on nickel foams via a simple and high-yield chemical vapor deposition (CVD). The morphologies were found to be dependent on the growth pressure. The obtained nanostructures have good crystallinity and uniform distribution. After coating amorphous silicon (a-Si) layers onto the obtained Ni3Si2 nanostructures by an inductively coupled plasma CVD, the architectures were assembled as anodes for lithium-ion batteries. High initial reversible specific capacity of 3733 mA h g−1 is obtained for the prepared a-Si coated Ni3Si2 nanowire electrode at a current density of 2.1 A g−1. After 50 cycles, the specific capacity still stays at above 2000 mA h g−1. When the current density is as high as 8.4 A g−1, the specific capacity maintains at about 1500 mA h g−1. For such core–shell configuration electrodes, the inactive and metallic Ni3Si2 core conducts electrons and provides a mechanically stable anchoring basis for the a-Si layers, resulting in improved electrochemical performance.
Co-reporter:Na Feng, Li Qiao, Duokai Hu, Xiaolei Sun, Peng Wang and Deyan He
RSC Advances 2013 vol. 3(Issue 21) pp:7758-7764
Publication Date(Web):20 Mar 2013
DOI:10.1039/C3RA40229K
Hierarchical ZnO–SnO2 composite nanofibers have been prepared through the single-nozzle electrospinning technique and subsequent calcinations using polyvinyl pyrrolidone as the fiber template and N,N-dimethylformamide as the solvent. The structures and morphologies of the samples were characterized by X-ray diffraction, Raman spectroscopy, scanning electron microscopy and transmission electron microscopy. The mesoporous nanofibers are composed of homogeneous grain-like nanoparticles, and heterostructures are formed between ZnO and SnO2. When used as the anode of lithium ion batteries, the ZnO–SnO2 composite nanofibers show first discharge and charge capacities of 1795 and 1364 mA h g−1 at a current density of 50 mA g−1. A reversible capacity of 588 mA h g−1 is obtained after 100 cycles. The ZnO–SnO2 composite nanofibers prepared by such a simple and cheap method are expected to have a potential application in energy storage.
Co-reporter:Zhiwei Wei, Xiucheng Wei, Yunxian Zheng, Deyan He
Materials Letters 2013 Volume 113() pp:163-166
Publication Date(Web):15 December 2013
DOI:10.1016/j.matlet.2013.09.086
•Anatase/rutile TiO2 encapsulated in well-graphitized carbon shells was prepared using a simple self-combustion method.•The weight ratio of anatase to rutile can easily be tuned.•The photocatalytic activity of anatase/rutile TiO2@C samples was investigated as a function of the proportion of anatase to rutile.Titanium oxides encapsulated in well-graphitized thin carbon shells were prepared directly by burning tetrabutyl titanate, and the effect of the proportion of anatase to rutile TiO2 on the photocatalytic activity was investigated in this paper. The preparation method of the materials is simple without special equipment and complex process control. The prepared anatase/rutile TiO2@C samples exhibit better photocatalytic activity under UV irradiation. The best photocatalytic activity can be obtained when the weight ratio of the anatase to rutile phase is 83.8: 16.2.
Co-reporter:Qi Wang, Xiaolei Sun, Deyan He, Junyan Zhang
Materials Chemistry and Physics 2013 Volume 139(Issue 1) pp:333-337
Publication Date(Web):15 April 2013
DOI:10.1016/j.matchemphys.2013.02.002
Carbon nano-onions were prepared by burning castor oil. The as-prepared carbon nano-onions were characterized by scanning electron microscopy and transmission electron microscope to confirm the nano-onion structures. The carbon nano-onions were used as anodes for rechargeable Li-ion batteries and demonstrated high reversible capacity and relatively good rate capability. The electrochemical performance can be attributed to the unusual surface properties and unique structural features of the carbon nano-onion anode, which amplify both surface area and extensive intermingling between curved graphite layer over small length scales, thereby leading to fast kinetics and short pathways for both Li ions and electrons.Highlights► Carbon nano-onions were prepared by castor oil. ► Carbon nano-onions were used as anode for Li-ion batteries. ► Good cycle performance.
Co-reporter:YingQi Liu;XiuWan Li;XiuCheng Wei
Science China Technological Sciences 2013 Volume 56( Issue 11) pp:2646-2648
Publication Date(Web):2013 November
DOI:10.1007/s11431-013-5367-2
The properties of piezoelectric PVDF films as separators are studied in NiO/Li electrodes Li-ion power cell. The results show that the PVDF piezoelectric film with excellent insulation is suitable for the environmental energy harvesting application. This is attributable to the compact structure of the piezoelectric PVDF film, and which make it has low leakage current and low charge-discharge current characteristics.
Co-reporter:Xiaolei Sun, Xinghui Wang, Na Feng, Li Qiao, Xiuwan Li, Deyan He
Journal of Analytical and Applied Pyrolysis 2013 100() pp: 181-185
Publication Date(Web):
DOI:10.1016/j.jaap.2012.12.016
Co-reporter:Zhibo Yang, Desheng Wang, Fei Li, Dequan Liu, Peng Wang, Xiuwan Li, Hongwei Yue, Shanglong Peng, Deyan He
Materials Letters 2013 90() pp: 4-7
Publication Date(Web):
DOI:10.1016/j.matlet.2012.09.006
Co-reporter:Yujun Fu, Xiuwan Li, Xiaolei Sun, Xinghui Wang, Dequan Liu and Deyan He
Journal of Materials Chemistry A 2012 vol. 22(Issue 34) pp:17429-17431
Publication Date(Web):03 Jul 2012
DOI:10.1039/C2JM33704E
Self-supporting Co3O4 with lemongrass-like morphology exhibits excellent rate capability and cyclic stability for high-performance Li ion batteries as electrodes. It retains a high reversible capacity of up to 981 mA h g−1 after 100 cycles at a rate of 0.5 C and a capacity higher than 381 mA h g−1 even at a rate as high as 10 C.
Co-reporter:Xiuwan Li, Dan Li, Li Qiao, Xinghui Wang, Xiaolei Sun, Peng Wang and Deyan He
Journal of Materials Chemistry A 2012 vol. 22(Issue 18) pp:9189-9194
Publication Date(Web):13 Mar 2012
DOI:10.1039/C2JM30604B
Interconnected porous MnO nanoflakes on nickel foam were prepared by a reduction of hydrothermal synthesized MnO2 precursor in hydrogen. The architectures were applied to lithium ion batteries as electrodes. Compared with the as-synthesized MnO2 anode, porous MnO nanoflakes showed superior cycling stability and rate performance. A high reversible capacity of 568.7 mA h g−1 was obtained at a current density of 246 mA g−1 for the second discharge. It retained a capacity of 708.4 mA h g−1 at the 200th charge–discharge cycle after cycling with various current densities up to 2460 mA g−1 and delivered a capacity of 376.4 mA h g−1 at a current density as high as 2460 mA g−1, indicating that the architecture of the porous MnO nanoflakes grown on Ni foam is a promising electrode for lithium ion batteries.
Co-reporter:Dequan Liu, Qi Wang, Li Qiao, Fei Li, Desheng Wang, Zhibo Yang and Deyan He
Journal of Materials Chemistry A 2012 vol. 22(Issue 2) pp:483-487
Publication Date(Web):10 Nov 2011
DOI:10.1039/C1JM13894D
A novel architecture of nickel current collector (NCC) is fabricated cost-effectively by electrospinning. An ultrathin MnO2 coating is electrodeposited on to the NCC and the resultant nano-networks of MnO2 shell/NCC core are used as supercapacitor electrodes. Excellent electrochemical performance is revealed at a high charge/discharge rate. The cyclic voltammetry measurements show that the current is stable even at a scan rate as fast as 200 mV s−1. A capacitance of 214 F g−1 is obtained by galvanostatic testing at a current density as large as 20 A g−1, which is much higher than that of MnO2 coated Ni foam.
Co-reporter:Xiaolei Sun, Xinghui Wang, Yanli Qin, Xiuwan Li, Li Qiao, Na Feng, Duokai Hu, Deyan He
Materials Letters 2012 Volume 66(Issue 1) pp:193-195
Publication Date(Web):1 January 2012
DOI:10.1016/j.matlet.2011.08.084
Novel pompon-like porous SnO2 with an average diameter of 900 nm has been successfully synthesized via a simple hydrothermal process with subsequent calcination treatment at 600 °C for 2 h in air. The crystalline structure and morphology of the resulting product were characterized by X-ray diffraction, micro-Raman spectrometer, field-emission scanning electron microscopy and transmission electron microscopy. The results indicate that the product is composed of self-assembly SnO2 pompon with a high purity tetragonal rutile-like structure. The lithium storage property of the obtained pompon-like porous SnO2 was evaluated by conventional discharge/charge test, showing a high initial discharge capacity of 1895 mAh g-1 at a current density of 100 mA g-1.Highlights► Novel pompon-like porous SnO2 was synthesized via a simple hydrothermal method. ► The product is highly porous and most of the fluffy nanosheets are linked together. ► The porous product has a high initial discharge capacity.
Co-reporter:Na Feng, Shanglong Peng, Xiaolei Sun, Li Qiao, Xiuwan Li, Peng Wang, Duokai Hu, Deyan He
Materials Letters 2012 Volume 76() pp:66-68
Publication Date(Web):1 June 2012
DOI:10.1016/j.matlet.2012.02.071
Monodisperse single crystal Zn2SnO4 cubes were synthesized via a facile hydrothermal method with low-cost reagents and characterized by X-ray powder diffraction, scanning electron microscopy and transmission electron microscopy. Their electrochemical performances were evaluated as anode materials of lithium ion batteries. It showed that the as-prepared sample is of high purity phase and in good crystallinity. The first discharge and charge capacities of the material are 1437 and 921 mA h g− 1. A higher reversible capacity of 775 mA h g− 1 was obtained after 20 cycles at a current density of 50 mA g− 1. The higher reversible capacity and good stability can be related to the special microstructural features of the material. Such Zn2SnO4 structures synthesized by the simple and cheap method are expected to have potential application in energy storage.Highlights► Single crystal Zn2SnO4 cubes were synthesized by a facile hydrothermal method. ► Pure Zn2SnO4 with good crystallinity are of uniform and well-dispersed cubic shape. ► The products exhibit high reversible capacity of 775 mA h g− 1 after 20 cycles.
Co-reporter:Xinghui Wang, Zhibo Yang, Xiaolei Sun, Xiuwan Li, Desheng Wang, Peng Wang and Deyan He
Journal of Materials Chemistry A 2011 vol. 21(Issue 27) pp:9988-9990
Publication Date(Web):27 May 2011
DOI:10.1039/C1JM11490E
NiO nanocone arrays were fabricated by a two-step approach for high power Li-ion battery applications. Galvanostatic battery tests show that the electrode can deliver a capacity up to 1058 mA h g−1 after 100 cycles at a low rate of 0.4 C and a capacity higher than 436 mA h g−1 even at a rate as high as 20 C.
Co-reporter:Xinghui Wang, Xiuwan Li, Xiaolei Sun, Fei Li, Qiming Liu, Qi Wang and Deyan He
Journal of Materials Chemistry A 2011 vol. 21(Issue 11) pp:3571-3573
Publication Date(Web):07 Feb 2011
DOI:10.1039/C0JM04356G
A simple thermal oxidation approach has been used to fabricate nanostructured NiO electrodes at a temperature as low as 400 °C in air. Galvanostatic battery testing showed that the NiO electrode exhibits excellent rate capability and high capacity. The performances can be attributed to its favorable morphology and the better electrical contact between NiO and Ni.
Co-reporter:Xiucheng Wei, Zhiwei Wei, Liping Zhang, Yingqi Liu, Deyan He
Journal of Colloid and Interface Science 2011 Volume 354(Issue 1) pp:76-81
Publication Date(Web):1 February 2011
DOI:10.1016/j.jcis.2010.10.049
A simple method was developed to prepare highly water-soluble nanocrystal powders of magnetic iron oxides with different oxidation degree from magnetite (Fe3O4) to maghemite (γ-Fe2O3) coated with gluconic acid (GLA). X-ray diffraction and transmission electron microscopy measurements show that the products have a narrow size distribution, and the cores are inverse spinel iron oxides and completely crystallized. Vibrating sample magnetometry measurements reveal that all the samples exhibit superparamagnetic behavior at room temperature. Fourier transform infrared (FTIR) and Raman spectra were used to identify the products. It is shown that GLA molecules are immobilized on the nanoparticle surface by chemical bonding and the carboxyl is asymmetrically bound to the surface iron atom, and the vacancies in the γ-Fe2O3 cores are disordered. Compared with FTIR, Raman spectrum analysis is a rapid, simple, and accurate method for identifying inverse spinel iron oxides. The chemical stability and the high solubility of the products are explained in terms of the proposed coordination modes of the surface iron atom with GLA.Graphical abstractHighly water-soluble nanocrystal powders of magnetite (Fe3O4, S1), partially oxidized magnetite (S2–S6) and maghemite (γ-Fe2O3, S7–S8), coated with gluconic acid (GLA).Research highlights► Highly water-soluble nanocrystal powders of magnetite and maghemite coated with gluconic acid (GLA) have been prepared and characterized. ► Raman spectra analysis is a rapid and simple method for qualitatively identifying the oxidation degree of spinel iron oxides. ► The proposed coordination modes of the surface iron atom with GLA well explain the chemical stability and the high solubility of the products.
Co-reporter:Desheng Wang, Zhibo Yang, Fei Li, Deyan He
Applied Surface Science 2011 Volume 257(Issue 20) pp:8350-8354
Publication Date(Web):1 August 2011
DOI:10.1016/j.apsusc.2011.03.136
Abstract
A series of nc-Si:H films with different crystalline volume fractions have been deposited by very high frequency glow discharge in a plasma with a silane concentration [SiH4]/([SiH4] + [H2]) varying from 2% to 10%. The nc-Si:H films have been characterized by Raman spectroscopy, XRD diffraction, and UV–vis–near infrared spectrophotometer. The deposition rate increases nearly linear with increasing the silane concentration while the crystalline volume fraction decrease from 58% to 12%. The refractive index and the absorption of the samples were obtained through a modified four-layer-medium transmission model based on the envelope method. It was found that the refractive indices and absorption coefficient increase with increasing silane concentration. Compared to the films deposited using conventional RF-PECVD with excitation frequency of 13.56 MHz, the samples prepared by very high frequency glow discharge have higher absorption coefficients, which is due to its better compactness and lower defect density.
Co-reporter:Desheng Wang, Zhibo Yang, Fei Li, Dequan Liu, Peng Wang, Deyan He
Applied Surface Science 2011 Volume 258(Issue 3) pp:1058-1061
Publication Date(Web):15 November 2011
DOI:10.1016/j.apsusc.2011.08.129
Abstract
Hydrogenated nanocrystalline Si (nc-Si:H) nanorod arrays were cost-effectively prepared on electrodeposited nickel nanocones substrates by very high frequency plasma enhanced vapor deposition. The antireflection properties of the obtained Si nanorod arrays were investigated carefully for the possible application in solar cells. It was found that the structures of nc-Si:H nanorod arrays can be tuned to obtain a very low reflectance especially in the near infrared region. The obtained Si nanostructure with well-separated nanorods, each of which had an average diameter of 200 nm and height of 700 nm, showed a reflectance value of <5% at normal incident over a wide wavelength of 400–1100 nm.
Co-reporter:Yanli Qin, Fei Li, Dequan Liu, Hengqing Yan, Jinxiao Wang, Deyan He
Materials Letters 2011 Volume 65(Issue 7) pp:1117-1119
Publication Date(Web):15 April 2011
DOI:10.1016/j.matlet.2011.01.033
Silicon nanowires were prepared by vapor–liquid–solid (VLS) mechanism at a growth temperature as low as 380 °C in an inductively coupled plasma chemical vapor deposition system. The nanowires consist of crystalline core surrounded by a thick amorphous silicon shell. An increase in plasma power produces dense and long nanowires with thick amorphous shell, accompanied with a thick uncatalyzed amorphous silicon film on the silicon substrate. Small catalyst nanoparticles are easier activated by plasma to grow the dense and thin nanowires in comparison with the large-size nanoparticles. Moreover, an enhanced optical absorption is achieved due to the strong light trapping and anti-reflection effects in the thin and tapered silicon nanowires with high density.
Co-reporter:Desheng Wang, Zhibo Yang, Fei Li, Xinghui Wang, Dequan Liu, Peng Wang, Deyan He
Materials Letters 2011 Volume 65(21–22) pp:3227-3229
Publication Date(Web):November 2011
DOI:10.1016/j.matlet.2011.07.022
Si–Ni nanorod structures as anode materials for Li ion batteries have been prepared by depositing Si coatings on electrodeposited Ni nanocone arrays using plasma enhanced chemical vapor deposition. The obtained samples were characterized by field emission scanning electron microscopy and X-ray diffraction. The electrochemical performance was evaluated by a galvanostatic battery testing. It is shown that the first discharge capacity is high as 4125 mAh/g with a high first coulombic efficiency of 92% at C/20 rate. A capacity of 3249 mAh/g at C/5 rate is attained with retention of 95.7% after 30 cycles.► Si-Ni nanorod structures have been prepared by PE-CVD technique. ► The well separated Si-Ni nanorods have a great advantage for Li ion batteries. ► Si-Ni nanorod anode exhibits a high capacity and a good capacity retention.
Co-reporter:Desheng Wang, Zhibo Yang, Fei Li, Dequan Liu, Xinghui Wang, Hengqing Yan, Deyan He
Materials Letters 2011 Volume 65(Issue 11) pp:1542-1544
Publication Date(Web):15 June 2011
DOI:10.1016/j.matlet.2011.02.082
Germanium coatings as an anode material of lithium-ion batteries have been deposited on electrodeposited nickel nanocone-arrays by very high frequency plasma enhanced chemical vapor deposition. The morphologies of the obtained nanostructures were characterized by field emission scanning electron microscopy in detail. The electrochemical performance was evaluated by a galvanostatic battery testing. It was shown that the anode exhibits a stable capacity of 590 mAh/g at a rate of C/10. A reversible specific capacity is retained to be 468 mAh/g at a rate of C/2 after 50 cycles, which is close to the value of the second cycle.
Co-reporter:Guo Zhou;Shibing Ni;Xiaolei Sun
Journal of Materials Science: Materials in Electronics 2011 Volume 22( Issue 2) pp:174-178
Publication Date(Web):2011 February
DOI:10.1007/s10854-010-0109-8
Sn1−xNixO2 nanostructures such as nanocubes, nanospheres and hollow spheres were synthesized by a simple hydrothermal method. Room temperature photoluminescence spectra of the as-synthesized samples display a strong yellow emission at about 600 nm and a weak blue emission at about 430 nm. The as-prepared and annealed Sn1−xNixO2 (x = 0, 0.01, 0.02, 0.04) were characterized by X-ray diffraction, field emission scanning electron microscopy, Raman spectrum, UV–Vis absorption spectra, and room temperature photoluminescence spectra. By investigating the relationship between the Raman band centered at 560 cm−1 and the photoluminescence of the samples, we suggest that the broad yellow emission and weak blue emission primarily originate from singly ionized oxygen vacancies and tin interstitials, respectively.
Co-reporter:Desheng Wang, Qiming Liu, Fei Li, Yanli Qin, Dequan Liu, Zeguo Tang, Shanglong Peng, Deyan He
Applied Surface Science 2010 Volume 257(Issue 4) pp:1342-1346
Publication Date(Web):1 December 2010
DOI:10.1016/j.apsusc.2010.08.068
Abstract
Hydrogenated microcrystalline silicon films have been prepared by plasma-enhanced chemical vapor deposition technique using silane diluted in H2 or H2 + Ar. The microstructures for silicon films have been evaluated by Raman scattering spectroscopy, X-ray diffraction and Fourier-transform infrared spectroscopy. Optical characterization has been done by UV–vis spectroscopy. It is found that the addition of Ar in diluent gases efficiently improves the deposition rate and crystallinity due to an enhanced dissociation of the source gas and the energy of deexcitation of Ar* released within the growth zone. Meanwhile, the enhanced crystallinity and the reducing of hydrogen ion bombardment with increasing Ar dilution lead to the polymerization and also a bad passivation of the hydrogen which cause the widening of the optical gap and increase of defect states in the μc-Si films. The absorption coefficient and dark conductivity are found to decrease basically with increasing Ar dilution corresponding to the widening optical gap and more defects. That the activation energy increases with increasing Ar dilution or decreasing hydrogen dilution is due to the fact that more defect states lead to a pulling down of the Fermi level.
Co-reporter:Shibing Ni, Xinghui Wang, Guo Zhou, Feng Yang, Junming Wang, Deyan He
Materials Letters 2010 Volume 64(Issue 4) pp:516-519
Publication Date(Web):28 February 2010
DOI:10.1016/j.matlet.2009.11.063
Copper vanadium oxide hydroxide hydrate (Cu3(OH)2V2O7·nH2O) nanoparticles with mean size of about 100 nm were successfully synthesized by a simple hydrothermal method. The structure and morphology of the as-synthesized products were characterized by X-ray diffraction (XRD), Field emission scanning electron microscopy (FE-SEM), Raman spectra, and Fourier transform infrared spectra (FTIR). The composition and purity of the as-synthesized Cu3(OH)2V2O7·nH2O nanoparticles were characterized by Energy disperse spectroscopy (EDS) and X-ray photoelectron spectroscopy (XPS). The magnetic property of the as-synthesized Cu3(OH)2V2O7·nH2O nanoparticles was characterized by vibrant sample magnetometer. Magnetic hysteresis curve indicate that the as-synthesized nanoparticles are of weak ferromagnetic property at room temperature.
Co-reporter:Xinghui Wang, Shibing Ni, Guo Zhou, Xiaolei Sun, Feng Yang, Junming Wang, Deyan He
Materials Letters 2010 Volume 64(Issue 13) pp:1496-1498
Publication Date(Web):15 July 2010
DOI:10.1016/j.matlet.2010.04.002
Well crystallized α-MnO2 nanowires (NWs) with an average diameter of about 40 nm and an average length of about 30 μm were successfully synthesized by hydrothermal method. The complex permittivity and permeability of α-MnO2 NWs/paraffin composites with 20 vol.% α-MnO2 NWs were measured in a frequency region from 0.1 to 13 GHz. The value of maximum reflection loss of the composites with 20 vol.% α-MnO2 NWs is approximately − 35 dB at 3.13 GHz with a thickness of 3.6 mm, and the bandwidth corresponding to reflection loss below − 10 dB is higher than 1.8 GHz with a lower thickness of 1.2 mm.
Co-reporter:Shibing Ni, Xiaolei Sun, Xinghui Wang, Guo Zhou, Feng Yang, Junming Wang, Deyan He
Materials Chemistry and Physics 2010 Volume 124(Issue 1) pp:353-358
Publication Date(Web):1 November 2010
DOI:10.1016/j.matchemphys.2010.06.046
Fe3O4 micro-spheres were synthesized by a simple chemical method at 90 °C. It was demonstrated that the final size and morphology of Fe3O4 was significantly affected by the additive NaF. The as-synthesized products were characterized by field emission scanning electron microscopy (FE-SEM), X-ray diffraction (XRD), vibrating sample magnetometer (VSM), and vector network analysis. The complex permittivity and permeability of paraffin wax and Fe3O4 with different Fe3O4 volume fraction were measured to increase linearly with increasing volume fraction of Fe3O4. When the matching thickness is 4 mm, the calculated reflection loss reaches a maximum value of −45.2 dB at 4.67 GHz with 40% volume fraction of Fe3O4.
Co-reporter:Shibing Ni, Guo Zhou, Xinghui Wang, Xiaolei Sun, Feng Yang, Yingqi Liu, Deyan He
Materials Chemistry and Physics 2010 120(2–3) pp: 426-430
Publication Date(Web):
DOI:10.1016/j.matchemphys.2009.11.030
Co-reporter:Feng Yang;Kai Huang;Shibing Ni;Qi Wang
Nanoscale Research Letters 2010 Volume 5( Issue 2) pp:
Publication Date(Web):2010 February
DOI:10.1007/s11671-009-9499-z
Photodetectors in a configuration of field effect transistor were fabricated based on individual W18O49 nanowires. Evaluation of electrical transport behavior indicates that the W18O49 nanowires are n-type semiconductors. The photodetectors show high sensitivity, stability and reversibility to ultraviolet (UV) light. A high photoconductive gain of 104 was obtained, and the photoconductivity is up to 60 nS upon exposure to 312 nm UV light with an intensity of 1.6 mW/cm2. Absorption of oxygen on the surface of W18O49 nanowires has a significant influence on the dark conductivity, and the ambient gas can remarkably change the conductivity of W18O49 nanowire. The results imply that W18O49 nanowires will be promising candidates for fabricating UV photodetectors.
Co-reporter:Jinxiao Wang, Pingqi Gao, Min Yin, Yanli Qin, Hengqing Yan, Junshuai Li, Shanglong Peng, Deyan He
Journal of Alloys and Compounds 2009 Volume 481(1–2) pp:278-282
Publication Date(Web):29 July 2009
DOI:10.1016/j.jallcom.2009.03.120
We prepared highly crystallized silicon films on Al-coated polyethylene napthalate (PEN) substrates using inductively coupled plasma chemical vapor deposition (ICP-CVD) at low temperature with a mixture of SiH4/H2 as the source gas. The microstructure of the films was evaluated using Raman spectroscopy, scanning electron microscope (SEM) and transmission electron microscopy (TEM). The effects of deposition parameters on the crystallinity of silicon films on bare and Al-coated PEN were systematically investigated. Compared to the films deposited on bare PEN, an obvious phase transition from amorphous to crystalline occurred when decreasing the SiH4 dilution ratio [R = [SiH4]/([SiH4] + [H2])] to 4% for the films on Al-coated substrates. With increasing the input power from 300 W to 400 W, the crystallinity of the films on bare and Al-coated PEN are both improved at a low temperature as low as 85 °C. The film on Al-coated PEN shows excellent crystallization with crystalline fraction of 82% and preferred orientation of (1 1 1). It has been found that the interaction between precursors and aluminum layers plays an important role and there should exist a different crystallization mechanism as compared to traditional annealing crystallization of amorphous Si/Al layer in the crystallization process of silicon films on Al-coated PEN at low temperature.
Co-reporter:Shibing Ni, Guo Zhou, Shumei Lin, Xinghui Wang, Qingtao Pan, Feng Yang, Deyan He
Materials Letters 2009 Volume 63(Issue 28) pp:2459-2461
Publication Date(Web):30 November 2009
DOI:10.1016/j.matlet.2009.07.070
Well crystallized zinc vanadium oxide hydroxide hydrate (Zn3(OH)2V2O7·nH2O) nanosheets have been successfully synthesized by a simple hydrothermal method. The products were characterized by X-ray diffraction (XRD), field-emission scanning electron microscopy (FE-SEM), and Raman spectrum. The composition of Zn3(OH)2V2O7·nH2O has been studied by thermal analysis (TG, DTA). The results indicate that there are two water molecules in Zn3(OH)2V2O7·nH2O molecular formula. Electrochemical properties of Zn3(OH)2V2O7·nH2O nanosheets as negative electrode of lithium ion battery were studied by conventional charge/discharge test, which shows steady platform near 1.4 V, suggesting it as an ideal candidate of negative material for lithium ion battery.
Co-reporter:Shibing Ni, Xinghui Wang, Guo Zhou, Feng Yang, Junming Wang, Qi Wang, Deyan He
Materials Letters 2009 Volume 63(Issue 30) pp:2701-2703
Publication Date(Web):31 December 2009
DOI:10.1016/j.matlet.2009.09.047
Well dispersed Fe3O4 nanoparticles with a mean diameter of about 160 nm were synthesized by a simple hydrothermal method in the presence of sodium sulfate. The products were characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), Raman spectrum, and Fourier transform infrared spectra (FTIR). Electrochemical properties of the nanostructured Fe3O4 as cathode electrodes of lithium ion battery were studied by conventional charge/discharge tests, showing a high initial discharge capacity of 1267 mA h g− 1 at a current density of 0.1 mA cm− 2.
Co-reporter:Qingtao Pan, Kai Huang, Shibing Ni, Feng Yang, Deyan He
Materials Research Bulletin 2009 44(2) pp: 388-392
Publication Date(Web):
DOI:10.1016/j.materresbull.2008.05.007
Co-reporter:Qi Wang, Bingwu Zhang, Mengnan Qu, Junyan Zhang, Deyan He
Applied Surface Science 2008 Volume 254(Issue 7) pp:2009-2012
Publication Date(Web):30 January 2008
DOI:10.1016/j.apsusc.2007.08.039
Abstract
Via a simple wet chemical etching followed by stearic acid modification, the presence of synergistic binary structures at micro- and nanometer scales and stearic acid bestows superhydrophobic property on steel and aluminum alloy surfaces. The as-prepared surfaces show superhydrophobic not only for pure water but also for corrosive liquids such as acid, basic and salt solutions. The stable superhydrophobicity of steel and aluminum alloy surfaces will extend their applications as engineering materials.
Co-reporter:Qi Wang, Chengbing Wang, Zhou Wang, Junyan Zhang, Deyan He
Applied Surface Science 2008 Volume 255(Issue 5) pp:1836-1840
Publication Date(Web):30 December 2008
DOI:10.1016/j.apsusc.2008.06.136
Abstract
Hydrogenated amorphous carbon films were prepared on Si (1 0 0) substrates by dc-pulse plasma chemical vapor deposition. The nature of the deposited films was characterized by Raman spectra and the stress relief patterns were observed by scanning electron microscope. Besides the well-known sinusoidal type and flower type patterns, etc., two different stress relief patterns, ring type and peg-top shape with exiguous tine on the top, were observed. The ring type in this paper was a clear ridge-cracked buckle and unusual. Two competing buckle delamination morphologies ring and sinusoidal buckling coexist. The ridge-cracked buckle in ring type was narrower than the sinusoidal buckling. Meanwhile peg-top shape with exiguous tine on the top in this paper was unusual. These different patterns supported the approach in which the stress relief forms have been analyzed using the theory of plate buckling.
Co-reporter:Shanglong Peng, Xiaoyan Shen, Zeguo Tang, Deyan He
Materials Chemistry and Physics 2008 Volume 107(2–3) pp:431-434
Publication Date(Web):15 February 2008
DOI:10.1016/j.matchemphys.2007.08.009
Au-induced crystallization of hydrogenated amorphous silicon–germanium thin films with chemical source (Au solution) at a low temperature (∼400 °C) has been investigated. The structure and morphology of the samples were characterized with X-ray diffraction, Raman spectra and scanning electron microscopy. The effects of annealing temperature and the Ge fraction on the Raman spectra were analyzed. The Raman shifts of Ge–Ge and Si–Ge peaks with the Ge fraction were also discussed. It was shown that Au solution significantly promotes the crystallization of the films at low temperature.
Co-reporter:Qingtao Pan, Jianfeng Jia, Kai Huang, Deyan He
Materials Letters 2007 Volume 61(4–5) pp:1210-1213
Publication Date(Web):February 2007
DOI:10.1016/j.matlet.2006.06.075
Well-crystalline Pb(Zr0.52Ti0.48)O3 square platelets, with dimensions of about 1 × 0.65 × 0.16 μm3, have been synthesized by hydrothermal method at low temperature. X-ray diffraction, micro-Raman spectrometry, and field emission scanning electron microscope were employed to study the crystal structure and morphologies of the products. Energy dispersive X-ray spectroscopy was used to analyze the elemental composition of the products. The photoluminescence of the products showed a strong narrow blue-light emission at 453 nm and a weak one at 468 nm at room temperature. The possible mechanisms for the blue-light emission are proposed in this report. The photoluminescence of this ferroelectric material is one more interesting property for technological applications.
Co-reporter:Shanglong Peng, Xiaoyan Shen, Zeguo Tang, Deyan He
Materials Science in Semiconductor Processing 2007 Volume 10(4–5) pp:150-154
Publication Date(Web):August–October 2007
DOI:10.1016/j.mssp.2007.10.002
Low-temperature (∼400 °C) metal-induced crystallization of hydrogenated amorphous Si0.5Ge0.5 thin films using Au solution has been investigated by X-ray diffraction, Raman spectra, scanning electron microscopy and atomic force microscopy. It was shown that Au solution significantly promotes the crystallization of the films at low temperatures. The effects of annealing temperature and concentration of the Au solution on the structure and morphology of the films were analyzed. The increase in crystallinity was observed with increasing the annealing temperature. The Raman shifts of Ge–Ge and Si–Ge peaks with the annealing temperature were also discussed.
Co-reporter:Qingtao Pan, Kai Huang, Shibing Ni, Qi Wang, Feng Yang, Deyan He
Materials Letters 2007 Volume 61(Issue 26) pp:4773-4776
Publication Date(Web):October 2007
DOI:10.1016/j.matlet.2007.03.025
Large-scale hierarchical CdS dendrites were synthesized by a simple hydrothermal method using 3CdSO4·8H2O and SC(NH2)2 as the original reactant. X-ray powder diffraction, transmission electron microscopy, selected-area electronic diffraction and X-ray photoelectron spectroscopy were carried out to characterize the product. The room-temperature photoluminescence (PL) reveals that the as-prepared CdS products have visible emission of about 485, 561 and 617 nm, and an infrared red (IR) emission centered at 750 nm. The possible photoluminescence mechanisms are proposed in this report. The photoluminescence of CdS dendrites enables them to have great applications in optoelectronic devices.
Co-reporter:Kai Huang, Qingtao Pan, Feng Yang, Shibi Ni, Deyan He
Physica E: Low-dimensional Systems and Nanostructures 2007 Volume 39(Issue 2) pp:219-222
Publication Date(Web):September 2007
DOI:10.1016/j.physe.2007.04.007
High-density, uniformly distributed and quasi-aligned tungsten oxide nanowire arrays have been synthesized by a conventional thermal evaporation approach on indium tin oxide (ITO) coated glass substrates without any catalysts. The temperature of the substrate was 450–550∘C. The tungsten oxide nanowires are single crystalline with growth direction of [0 1 0]. For commercial applications, field emission properties of tungsten oxide nanowires were studied under a poor vacuum at room temperature. The electron field-emission turn-on field (Eto)(Eto), defined as the macroscopic field required to produce a current density of 10μA/cm2, is about 3.6V/μm. The performance reveals that the tungsten oxide nanowire arrays can be served as a good candidate for commercial application in field-emission displays.
Co-reporter:H. Hu;D. He
Chemical Vapor Deposition 2006 Volume 12(Issue 12) pp:
Publication Date(Web):12 DEC 2006
DOI:10.1002/cvde.200506528
Si1–xGex films with nanodot arrays are prepared on anodic aluminum oxide (AAO) templates by plasma-enhanced (PE)CVD. The structure and morphology of the films are investigated using X-ray diffraction (XRD) spectroscopy and transmission electron microscopy (TEM). It is found that the size of the Si1–xGex grains is controlled by the pore diameter of the alumina substrate, which can be modulated during the preparation process. Intense visible photoluminescence (PL) is observed from the samples, and a remarkable red-shift of the luminescence peak position is shown with increase in the content of Ge. Conductivity measurements show that electron tunneling is enhanced with increase of the strains stored in the sample.
Co-reporter:Peifeng Zhang, Xiaoping Zheng, Suoping Wu, Jun Liu, Deyan He
Vacuum 2004 Volume 72(Issue 4) pp:405-410
Publication Date(Web):16 January 2004
DOI:10.1016/j.vacuum.2003.08.013
A three-dimensional kinetic Monte Carlo technique has been developed for simulating the growth of thin Cu films. The model involves incident atom attachment, surface diffusion of the atoms on the growing surface and atom detachment from the growing surface. A significant improvement in calculation of activation barriers for the surface atom diffusion on the growing film was made. The related effects caused by surface atom diffusion were taken into account. The results showed that there exist a transition temperature Tt at a certain deposition rate. When the substrate temperature approaches Tt, the growing surface becomes smoother and the relative density of the films increases. The surface roughness minimizes and the relative density saturates at Tt. The surface roughness increases with increased substrate temperature when the temperature is higher than Tt. Tt is a function of the deposition rate. The influence of the deposition rate on the surface roughness is dependent on the substrate temperature. The simulation results also showed that the relative density decreases with increasing deposition rate and average thickness of the film.
Co-reporter:Deyan He, Wenjuan Cheng, Juan Qin, Jinshun Yue, Erqing Xie, Guanghua Chen
Applied Surface Science 2002 Volume 191(1–4) pp:338-343
Publication Date(Web):17 May 2002
DOI:10.1016/S0169-4332(02)00254-4
Abstract
Ternary boron carbonitride (BCN) thin films were deposited by radio frequency reactive sputtering. X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared (FT-IR) absorption measurements suggested that the films are atomic-level hybrids composed of B, C and N atoms. The structure of the samples is graphitic BC2N. High compressive stresses were observed in the films deposited on silicon and fused silica substrates. When the films were peeled off the substrates, the absorption bands in the FT-IR spectra shift to lower wavenumbers due to the stress relief. The compressive stresses caused buckling of the films, and the buckling patterns were related to the used substrates. For the samples deposited on Si wafer, a branching type buckling pattern was observed, while a telephone-cord morphology was noted for the samples deposited on fused silica plate. The telephone-cord morphology can be explained based on the buckling-driven delamination theory proposed by Oritiz and Gioia [J. Mech. Phys. Solids 42 (1994) 531].
Co-reporter:Deyan He, Lexi Shao, Weibin Gong, Erqing Xie, Kang Xu, Guanghua Chen
Diamond and Related Materials 2000 Volume 9(9–10) pp:1600-1603
Publication Date(Web):September–October 2000
DOI:10.1016/S0925-9635(00)00313-7
Electron transport and electron field emission of nanometer-size diamond powders coated on quartz and n+-type Si substrates have been characterized. The nanodiamond powders were synthesized by explosive detonation. The measurement of temperature-dependent conductivity shows that the conduction of the nanodiamond coating is non-Arrhenius leading to an interesting behavior at low temperatures. The material shows a good behavior of electron field emission. In the electric field range from 3 to 5 V/μm, the emission can be approximately described by the Fowler–Nordheim (F–N) equation. A stable emission current density as high as ∼95 mA/cm2 was obtained under an applied field of 5 V/μm. It has been suggested that the novel electron transport and the high emission current density of the samples might originate from their non-continuous network structure of the nanodiamond particles.
Co-reporter:Jinshun Yue, Wenjuan Cheng, Xingwang Zhang, Deyan He, Guanghua Chen
Thin Solid Films 2000 Volume 375(1–2) pp:247-250
Publication Date(Web):31 October 2000
DOI:10.1016/S0040-6090(00)01337-7
Ternary boron carbonitride (BCN) thin films were prepared by radio frequency reactive sputtering method from a hexagonal (h-) BN target in an Ar-CH4 discharge. The films with different C contents were obtained by varying the CH4 partial pressure. The samples were characterized by X-ray diffraction, Fourier transform infrared spectroscopy, and X-ray photoelectron spectroscopy. The results suggest that the material is not a simple mixture of h-BN and graphite. The samples deposited under the optimum conditions are polycrystalline BC2N. With increasing CH4 partial pressure, more B atoms prefer to combine with C atoms. The temperature dependent conductivity of the films deposited at 10% CH4 partial pressure follows the Arrhenius relation; the corresponding activation energy is approximately 0.8 eV.
Co-reporter:Lexi Shao, Erqing Xie, Deyan He, Guanghua Chen
Materials Science and Engineering: B 1999 Volume 60(Issue 2) pp:83-87
Publication Date(Web):15 June 1999
DOI:10.1016/S0921-5107(99)00010-0
Electron field emission characteristics from chemical vapor deposition (CVD) diamond thin films implanted with nitrogen have been investigated. It is shown that the formation of a stable emission from these films is characterized by a three-stage process of breakdown of the implanted layer, activation of the emitter and turn-on of the stable emission. On the basis of the experiment results, a modified activation model has been suggested to analyze the mechanisms of the emission.
Co-reporter:Jinxiao Wang, Yanli Qin, Hengqing Yan, Pingqi Gao, ... Deyan He
Physics Procedia (2011) Volume 18() pp:128-135
Publication Date(Web):1 January 2011
DOI:10.1016/j.phpro.2011.06.070
Inductively coupled plasma (ICP) system with the adjustable distance (d) between the inductance coil and substrates was designed to effectively utilize the spatial confinement of ICP discharge, and then control the gas-phase transport process. The effects of the distance on the microstructures and optical properties of silicon films were systematically investigated in our work. The investigation was conducted in the ICP-chemical vapor deposition process with a mixture of SiH4/H2 as the source gas at a low temperature of 240 °C. Characterization of the films with X-ray diffraction and Raman spectroscopy revealed that the crystallinity and crystallite size firstly increased and then decreased with increasing the distance. The maximum was reached at the distance of 5 cm. By SEM measurements, the film morphologies were shown to be consistent with the XRD and Raman analysis results. The Fourier transform infrared (FTIR) spectroscopic analysis showed the hydrogen was predominantly incorporated in the silicon films in the mono-hydrogen (Si–H) bonding configuration. With increasing the distance, the hydrogen content in the silicon films exhibited similar behavior with crystallinity of silicon films. Based on the results, a gas-phase transport process was suggested for the deposition of silicon films in ICP-CVD system. Furthermore, the Tauc's optical band gap achieved the maximum of 1.68 eV with the distance of 5 cm. Besides the effect of hydrogen content, the quantum size effect might also be responsible for higher band gap in crystalline silicon films.
Co-reporter:Xiuwan Li, Dan Li, Li Qiao, Xinghui Wang, Xiaolei Sun, Peng Wang and Deyan He
Journal of Materials Chemistry A 2012 - vol. 22(Issue 18) pp:
Publication Date(Web):
DOI:10.1039/C2JM30604B
Co-reporter:Xiuwan Li, Zhibo Yang, Shumei Lin, Dan Li, Hongwei Yue, Xiaonan Shang, Yujun Fu and Deyan He
Journal of Materials Chemistry A 2014 - vol. 2(Issue 36) pp:NaN14821-14821
Publication Date(Web):2014/07/23
DOI:10.1039/C4TA03304C
Silicon is considered as a promising candidate for next-generation lithium-ion battery anodes. However, severe capacity fading caused by volume change during Li-ion insertion and extraction hinders its practical application. In this work, gold granular film and polyvinylidene fluoride coating are sequentially prepared on the deposited Si film to solve the aforementioned problem.
Co-reporter:Xiuwan Li, Li Qiao, Dan Li, Xinghui Wang, Wenhe Xie and Deyan He
Journal of Materials Chemistry A 2013 - vol. 1(Issue 21) pp:NaN6406-6406
Publication Date(Web):2013/03/22
DOI:10.1039/C3TA10821J
Three-dimensional network structured α-Fe2O3 was prepared by a facile chemical corrosion of a stainless steel plate followed by thermal oxidation. When the architecture was directly used as an electrode for lithium ion batteries (LIBs), a high reversible capacity of 858.2 mA h g−1 was obtained at a current density of 200 mA g−1 for the 2nd discharge. Especially, it retained a capacity of 1105.6 mA h g−1 at the 100th discharge–charge cycle. The mechanism behind the capacity increase with cycling has been investigated based on the capacity changes in different voltage regions. After cycling with various current densities, it can deliver a capacity of 520.0 mA h g−1 at a current density as high as 5000 mA g−1, indicating that the electrode prepared by such a simple route can be a promising candidate for high-power LIBs.
Co-reporter:Yujun Fu, Xiuwan Li, Xiaolei Sun, Xinghui Wang, Dequan Liu and Deyan He
Journal of Materials Chemistry A 2012 - vol. 22(Issue 34) pp:NaN17431-17431
Publication Date(Web):2012/07/03
DOI:10.1039/C2JM33704E
Self-supporting Co3O4 with lemongrass-like morphology exhibits excellent rate capability and cyclic stability for high-performance Li ion batteries as electrodes. It retains a high reversible capacity of up to 981 mA h g−1 after 100 cycles at a rate of 0.5 C and a capacity higher than 381 mA h g−1 even at a rate as high as 10 C.
Co-reporter:Xinghui Wang, Xiuwan Li, Xiaolei Sun, Fei Li, Qiming Liu, Qi Wang and Deyan He
Journal of Materials Chemistry A 2011 - vol. 21(Issue 11) pp:NaN3573-3573
Publication Date(Web):2011/02/07
DOI:10.1039/C0JM04356G
A simple thermal oxidation approach has been used to fabricate nanostructured NiO electrodes at a temperature as low as 400 °C in air. Galvanostatic battery testing showed that the NiO electrode exhibits excellent rate capability and high capacity. The performances can be attributed to its favorable morphology and the better electrical contact between NiO and Ni.
Co-reporter:Na Feng, Duokai Hu, Peng Wang, Xiaolei Sun, Xiuwan Li and Deyan He
Physical Chemistry Chemical Physics 2013 - vol. 15(Issue 24) pp:NaN9930-9930
Publication Date(Web):2013/04/23
DOI:10.1039/C3CP50615K
We report a facile and reproducible synthesis of nanostructured Ni3S2 films by a hydrothermal route with Ni foam as the precursor reactant and substrate. The synthetic mechanism was examined by investigating the dependence of the films' crystal morphologies on the hydrothermal duration, and uniform nanostructured Ni3S2 films with a porous carpet-like morphology were synthesized on the substrates. The architectures were used as cathodes for lithium ion batteries (LIBs), and their electrochemical performances were evaluated as a function of the film thickness. The first discharge and charge capacities were 596 and 466 mA h g−1 for the electrode with an optimal film thickness and a higher reversible capacity of 421 mA h g−1 was obtained after 60 cycles at a current density of 50 mA g−1. The simplicity of the synthetic methodology and the better electrochemical performance make the synthesized Ni3S2 films a promising cathode material for next-generation LIBs.
Co-reporter:Xinghui Wang, Zhibo Yang, Xiaolei Sun, Xiuwan Li, Desheng Wang, Peng Wang and Deyan He
Journal of Materials Chemistry A 2011 - vol. 21(Issue 27) pp:NaN9990-9990
Publication Date(Web):2011/05/27
DOI:10.1039/C1JM11490E
NiO nanocone arrays were fabricated by a two-step approach for high power Li-ion battery applications. Galvanostatic battery tests show that the electrode can deliver a capacity up to 1058 mA h g−1 after 100 cycles at a low rate of 0.4 C and a capacity higher than 436 mA h g−1 even at a rate as high as 20 C.
Co-reporter:Dequan Liu, Qi Wang, Li Qiao, Fei Li, Desheng Wang, Zhibo Yang and Deyan He
Journal of Materials Chemistry A 2012 - vol. 22(Issue 2) pp:NaN487-487
Publication Date(Web):2011/11/10
DOI:10.1039/C1JM13894D
A novel architecture of nickel current collector (NCC) is fabricated cost-effectively by electrospinning. An ultrathin MnO2 coating is electrodeposited on to the NCC and the resultant nano-networks of MnO2 shell/NCC core are used as supercapacitor electrodes. Excellent electrochemical performance is revealed at a high charge/discharge rate. The cyclic voltammetry measurements show that the current is stable even at a scan rate as fast as 200 mV s−1. A capacitance of 214 F g−1 is obtained by galvanostatic testing at a current density as large as 20 A g−1, which is much higher than that of MnO2 coated Ni foam.
Co-reporter:Yujun Fu, Zhibo Yang, Xiuwan Li, Xinghui Wang, Dequan Liu, Duokai Hu, Li Qiao and Deyan He
Journal of Materials Chemistry A 2013 - vol. 1(Issue 34) pp:NaN10007-10007
Publication Date(Web):2013/06/21
DOI:10.1039/C3TA11753G
3D interconnected network Ni nanofoams with large surface area were fabricated by a template-free approach. Their pore size and skeleton diameter are 150–350 nm and 200–300 nm, respectively. The homogeneous foaming structure and the metallic ductility of the Ni nanofoams make them suitable to be used as nanostructured current collectors. The Ni/NiO nanostructures were prepared by in situ thermal oxidation of the obtained Ni nanofoams. As anodes of lithium ion batteries, the Ni/NiO nanofoam electrodes deliver excellent cycling stability, superior rate capability, and high areal capacity. A high reversible capacity of 835 mA h g−1, which corresponds to an areal capacity of 2.1 mA h cm−2, was obtained after 200 cycles at a current rate of 0.5 C (1 C = 718 mA g−1). The Ni nanofoams exhibit an excellent electrochemical stability in electrolytes and are compatible with various electrochemically active materials as potential nanostructured current collectors for high-performance energy storage devices. Moreover, the preparation approach of the Ni nanofoams is facile, cost-effective, and can be used for large-scale production.
Co-reporter:Hongwei Yue, Fei Li, Zhibo Yang, Xiuwan Li, Shumei Lin and Deyan He
Journal of Materials Chemistry A 2014 - vol. 2(Issue 41) pp:NaN17358-17358
Publication Date(Web):2014/08/28
DOI:10.1039/C4TA04095C
Carbon nanofibers (CNFs) were deposited on Cu foam by a floating catalyst method, and a Mn3O4 layer was then coated onto the deposited CNFs via a hydrothermal process based on the redox reaction of carbon and potassium permanganate. The obtained architecture of Mn3O4-coated CNFs (CNFs@Mn3O4) on Cu foam was directly used as an anode for lithium-ion batteries without using any binder or conducting additive. The anode showed high reversible capacity, good cycle stability and superior rate capability. A reversible capacity of up to 1210.4 mA h g−1 was obtained after 50 cycles at a current density of 100 mA g−1. When the current density increased to 5000 mA g−1, it could deliver a capacity of more than 300 mA h g−1. The excellent electrochemical performance could be attributed to the unique morphology of the CNFs@Mn3O4 nanocomposites, which can buffer the volume change, decrease the contact resistance, shorten the ionic diffusion path and make the electron transport more efficient.
Co-reporter:Xinghui Wang, Li Qiao, Xiaolei Sun, Xiuwan Li, Duokai Hu, Qing Zhang and Deyan He
Journal of Materials Chemistry A 2013 - vol. 1(Issue 13) pp:NaN4176-4176
Publication Date(Web):2013/02/08
DOI:10.1039/C3TA01640D
Mesoporous NiO nanosheet networks with a thickness of more than 5 μm were fabricated on Ni foam for application as an electrode in Li ion batteries. Benefiting from the favorable macro/meso-porous structures as well as the great loading of the synthesized NiO, the electrode exhibits high capacity and excellent rate capability.
Co-reporter:Fei Li, Yanli Qin, Hongwei Yue, Zhibo Yang, Xiuwan Li and Deyan He
Journal of Materials Chemistry A 2014 - vol. 2(Issue 24) pp:NaN9163-9163
Publication Date(Web):2014/03/25
DOI:10.1039/C4TA01171F
NiO layers were coated in situ onto Ni-silicide nanowires by an oxidation in air. The surface of the nanowires had been previously roughened by etching in HF solution. It is found that the roughened surface is very helpful to enhance the in situ coating ability of NiO on the nanowires. When the resulting samples were used as anodes for lithium-ion batteries, a high reversible capacity of 1.28 mA h cm−2 was obtained for the surface-roughened nanowires with 30 min HF-treatment, which is 3 times higher than that of the nanowires without HF-treatment. The current density can reach up to 2.15 mA cm−2 for the 60 min HF-treated and then oxidized nanowires, while the capacity is maintained at as high as 0.52 mA h cm−2. The improved cyclic performance could be attributed to the roughened surface of the nanowires, which enhanced the coating ability of the NiO layers, and provided a porous structure that is of benefit to increase the area of the electrode/electrolyte interface for the adsorption of ions. In addition, the Ni-silicide nanowires can improve the electrode conductivity and act as a stable support for the NiO coating layers during cycling, making a positive contribution to the electrochemical performance.
Co-reporter:Suyuan Li, Wenhe Xie, Suiyan Wang, Xinyu Jiang, Shanglong Peng and Deyan He
Journal of Materials Chemistry A 2014 - vol. 2(Issue 40) pp:NaN17145-17145
Publication Date(Web):2014/08/26
DOI:10.1039/C4TA03907F
The reduced graphene oxide/SnO2 (rGO/SnO2) composite was facilely synthesized via a modified colloidal coagulation method and a subsequent reduction. As an anode for lithium ion batteries, it delivers a high reversible capacity of 795 mA h g−1 in the 600th cycle at a current density of 1000 mA g−1. The excellent electrochemical performances are mainly due to its morphology stability and the reversible reaction between the formed Li2O and Sn to yield SnO2, as confirmed by XPS and TEM characterization after 200 cycles.
Co-reporter:Jun Tang, Dequan Liu, Yunxian Zheng, Xiuwan Li, Xinghui Wang and Deyan He
Journal of Materials Chemistry A 2014 - vol. 2(Issue 8) pp:NaN2591-2591
Publication Date(Web):2013/11/20
DOI:10.1039/C3TA14042C
Interconnected α-Co(OH)2 nanosheets with various proportions of substituted Zn were electrochemically deposited on nickel foam substrates. The architectures were used directly as electrodes for supercapacitors, which exhibited excellent pseudocapacitive performance. Compared with the pure α-Co(OH)2 nanosheet electrode with a capacitance loss of 17.5% after 2000 cycles, the 9.7 at.% Zn-substituted α-Co(OH)2 electrode showed stabilized capacitance with a loss of 1.1%, and the electrode with 21.1 at.% Zn substitution demonstrated a high cycling stability with a capacitance loss of only 0.6% from 652 F g−1 after 2000 cycles. The enhanced cycling stability is attributed to the stabilization of the structure of the materials by the incorporation of inactive Zn2+ ions.
Co-reporter:Dan Li, Xiuwan Li, Xiaoyi Hou, Xiaolei Sun, Boli Liu and Deyan He
Chemical Communications 2014 - vol. 50(Issue 66) pp:NaN9364-9364
Publication Date(Web):2014/06/04
DOI:10.1039/C4CC01311E
A Ni3S2 nanotube array has been synthesized on Ni foam using a template-free hydrothermal method. The Ni foam acts as both the reactant and support. The resulting architecture as an electrode for lithium ion batteries benefits from the unique morphology and exhibits excellent electrochemical performance with high capacity, long cycle life and superior rate capability.
Co-reporter:Zhengjiao Liu, Shuai Bai, Boli Liu, Pengqian Guo, Mingzhi Lv, Dequan Liu and Deyan He
Journal of Materials Chemistry A 2017 - vol. 5(Issue 25) pp:NaN13175-13175
Publication Date(Web):2017/05/31
DOI:10.1039/C7TA03576D
Carbonized melamine formaldehyde foam has been modified with a thin titanium layer and then used as an inexpensive and lightweight current collector. By depositing a silicon film on the thin Ti layer modified carbon foam, a self-supported Si electrode was obtained for lithium-ion batteries (LIBs). The Ti/Si interface has been further strengthened by annealing treatment, which dramatically suppressed the electrode pulverization induced by the huge volume changes of silicon in cycles. The self-supported Si electrode displayed a high rechargeable specific capacity of 1296 mA h g−1 at a current density of 2.0 A g−1 and excellent cycling performance up to 1000 cycles. When the prepared Si electrode was paired with a casted LiCoO2 (LCO) electrode to design a Si/LCO full-cell LIB, it displayed a reversible charge/discharge capability in all 200 cycles. As a result of the lightweight carbon foam collector, the self-supported electrode assembly strategy and the high specific capacity of silicon, a high-energy density of 479.5 W h kg−1 was attained. The thin titanium layer modification can be applied to improve the contact interface between other carbonaceous current collectors and active materials with inferior electronic conductivity and large volume changes in cycles.
