Co-reporter:Yuting Wu, Ping Nie, Jiang Wang, Hui Dou, and Xiaogang Zhang
ACS Applied Materials & Interfaces November 15, 2017 Volume 9(Issue 45) pp:39610-39610
Publication Date(Web):October 17, 2017
DOI:10.1021/acsami.7b12155
The global availability of sodium makes the exploration of superior sodium-ion batteries attractive for energy storage application. MXenes, as one of the most promising anodes for sodium-ion batteries, have been reported to have many advantages, such as high electronic conductivity and a hydrophilic surface. However, the compact multilayer structure and deficient delamination significantly inhibits their application, requiring high energy and showing decreased storage capacity and poor rate capabilities. Few-layer MXene has been proved to benefit superior electrochemical properties with a better ionic conductivity and two-dimensional layer structure. Herein, we report scale delamination of few-layer MXene nanosheets as anodes for sodium-ion batteries, which are prepared via an organic solvent assist high-energy mechanical-milling method. This approach efficiently prevents the oxidation of MXene and produces few-layer nanosheets structure, facilitating fast electron transport and Na+ diffusion. Electrochemical tests demonstrate that the few-layer MXenes show high specific capacity, excellent cycle stability, and good rate performance. Specifically, few-layer MXene nanosheets deliver a high reversible capacity of 267 mA h g–1 at a current density of 0.1 A g–1. After cycling 1500 cycles at a high rate of 1 A g–1, a reversible capacity of 76 mA h g–1 could be maintained.Keywords: anode; DMSO; few layers; high-energy mechanical milling; MXene; sodium-ion batteries;
Co-reporter:Ping Nie, Xiaoyan Liu, Ruirui Fu, Yuting Wu, Jiangmin Jiang, Hui Dou, and Xiaogang Zhang
ACS Energy Letters June 9, 2017 Volume 2(Issue 6) pp:1279-1279
Publication Date(Web):May 2, 2017
DOI:10.1021/acsenergylett.7b00286
The silicon anode holds great potential for next-generation lithium-ion batteries in view of its high gravimetric capacity and natural abundance. The main challenges associated with silicon are the structural degradation and instability caused by huge volume change upon cycling. We report herein polybenzimidazole (PBI) derived pyrrolic N-enriched carbon as an ideal encapsulation onto microsized silicon spheres, which is achieved by an aerosol-assisted assembly combined with a simple physisorption process. The new polymer derived carbon endows silicon with the structural and compositional characteristics of intrinsic high electronic conductivity, abundant pyrrolic nitrogen, and structure robustness. The resulting mesoporous Si-PBI carbon composite exhibits excellent lithium storage performance in terms of high reversible specific capacity of 2172 mAh g–1, superior rate capability (1186 mAh g–1 at 5 A g–1), and prolonged cycling life. As a result, a fabricated Si/LiCoO2 full battery demonstrates high energy density of 367 Wh kg–1 as well as good cycling stability for 100 cycles.
Co-reporter:Ping Nie, Jiaren Yuan, Jie Wang, Zaiyuan Le, Guiyin Xu, Liang Hao, Gang Pang, Yuting Wu, Hui Dou, Xiaohong Yan, and Xiaogang Zhang
ACS Applied Materials & Interfaces June 21, 2017 Volume 9(Issue 24) pp:20306-20306
Publication Date(Web):June 1, 2017
DOI:10.1021/acsami.7b05178
Alternative battery systems based on the chemistry of sodium are being considered to offer sustainability and cost-effectiveness. Herein, a simple and new method is demonstrated to enable nickel hexacyanoferrate (NiHCF) Prussian blue analogues (PBA) nanocrystals to be an excellent host for sodium ion storage by functionalization with redox guest molecule. The method is achieved by using NiHCF PBA powders infiltrated with the 7,7,8,8-tetracyanoquinododimethane (TCNQ) solution. Experimental and ab initio calculations results suggest that TCNQ molecule bridging with Fe atoms in NiHCF Prussian blue analogue leads to electronic coupling between TCNQ molecules and NiHCF open-framework, which functions as an electrical highway for electron motion and conductivity enhancement. Combining the merits including high electronic conductivity, open framework structure, nanocrystal, and interconnected mesopores, the NiHCF/TCNQ shows high specific capacity, fast kinetics and good cycling stability, delivering a high specific capacity of 35 mAh g–1 after 2000 cycles, corresponding a capacity loss of 0.035% decay per cycle.Keywords: electronic coupling; fast kinetics; Prussian blue analogue; sodium ion batteries; TCNQ;
Co-reporter:Chengyang Xu, Guiyin Xu, Yadi Zhang, Shan Fang, Ping Nie, Langyuan Wu, and Xiaogang Zhang
ACS Energy Letters - New in 2016 December 8, 2017 Volume 2(Issue 12) pp:2659-2659
Publication Date(Web):October 19, 2017
DOI:10.1021/acsenergylett.7b00884
Although the soluble redox mediator (RM) has been effectively applied in Li–O2 batteries, parasitic reactions between the lithium anode and RM+ can result in poor cycle performance. Herein, we proposed a nonelectroactive surfactant (sodium dodecyl sulfate, SDS) that could adsorb on the hydrophobic carbon surface and form a stable anionic layer upon charge, which can effectively suppress the diffusion of oxidized RM+ and facilitate charge transfer at the electrode–solution interface. To coordinate with SDS, a new RM named 2-phenyl-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide (PTIO) was adopted due to its oxidation process following after in situ formation of the anionic layer. Moreover, as a bifunctional mediator, PTIO cannot only get a low charge plateau but also greatly enhance the discharge capacity when applied in Li–O2 batteries. The electrochemical results demonstrated that the cycling performance, energy efficiency, and discharge capacity were significantly improved owing to the synergistic effect of PTIO and SDS.
Co-reporter:Guiyin Xu, Qing-bo Yan, Akihiro Kushima, Xiaogang Zhang, Jin Pan, Ju Li
Nano Energy 2017 Volume 31() pp:568-574
Publication Date(Web):January 2017
DOI:10.1016/j.nanoen.2016.12.002
•A conductive composite binder with high electric conductivity and strong adhesion was obtained by a simple solution process.•The conductive composite binder could trap lithium polysulfides by a chemical absorption.•Lithium-sulfur batteries using the conductive composite binder exhibit excellent electrochemical performance.Lithium-sulfur batteries have high cathode theoretical energy density, but the poor conductivity of sulfur and polysulfide shuttling result in serious polarization and low sulfur utilization. Moreover, the addition of insulating binder in the electrode increases the internal resistance, reducing specific capacity and rate performance. Herein, we develop a composite binder with higher electronic conductivity, superior mechanical property and strong adsorption of polysulfides that imparts it some electrocatalytic activity. The reduced graphene oxide- polyacrylic acid (GOPAA) binder is prepared via a simple solution process. At constant loading fraction of 10 wt%, using GOPAA binder induces a 30% enhancement in the cathode capacity, better cycle life and rate capability compared to using PAA binder, reducing both the local charge-transfer resistance and the global electronic resistance before and after cycling. These are attributed to the enhanced binding strength and synergistic effect of reduced graphene oxide and PAA forming well-dispersed conductive bridges to promote rapid electron transfer. Additionally, GOPAA provides active sites for adsorption of lithium polysulfides and electrocatalytic activity, shifting redox peaks in cyclic voltammetry and improving roundtrip efficiency.
Co-reporter:Shengyang Dong;Hongsen Li;Junjun Wang;Xiulei Ji
Nano Research 2017 Volume 10( Issue 12) pp:4448-4456
Publication Date(Web):01 September 2017
DOI:10.1007/s12274-017-1753-6
Flexible power devices play an increasingly crucial role in emerging flexible electronics. To improve the electrochemical performance of flexible power devices, novel electrode structures and new energy-storage systems should be designed. Herein, a novel flexible Li-ion hybrid capacitor (LIC) is designed based on an anode comprising Li4Ti5O12 nanoplate arrays coated on carbon textile (LTO/CT) and a cathode comprising a flexible N-doped graphene/carbon-nanotube composite (NGC) film. The LTO/CT anode is fabricated by directly growing Li4Ti5O12 nanoplates on CT with robust adhesion using a simple one-pot hydrothermal reaction. Considering the volume of a real-device flexible LIC, the NGC//LTO/CT configuration delivers high volumetric energy and power densities of 2 mWh·cm−3 and 185 mW·cm−3, respectively. Furthermore, the flexible LIC shows excellent flexibility and electrochemical stability, with extremely small capacity fluctuation under different bending states. This work demonstrates a scalable route to assemble flexible LICs as high-performance power devices.
Co-reporter:Shengyang Dong, Zhifei Li, Ismael A. Rodríguez-Pérez, Heng Jiang, Jun Lu, Xiaogang Zhang, Xiulei Ji
Nano Energy 2017 Volume 40(Volume 40) pp:
Publication Date(Web):1 October 2017
DOI:10.1016/j.nanoen.2017.08.022
•A new dual-ion battery configuration with NTO@G anode and polycyclic aromatic hydrocarbon (PAH) cathode.•Moderate operating voltage at conventional alkyl carbonate electrolyte.•The record-long cycling life of dual-ion batteries.•Good electrochemical performance at different temperatures from −20 to 40 °C.Here we construct a novel sodium dual-ion battery (Na-DIB) with a conventional alkyl/alkylene carbonate electrolyte by using reduced-graphene-oxide-coated Na2Ti3O7 (NTO@G) as the anode and coronene, a polycyclic aromatic hydrocarbon (PAH), as the cathode. The coronene//NTO@G configuration delivers a specific energy of 77 W h kg−1, based on the total active mass in both electrodes, and excellent cycling stability with 80% capacity retention after 5000 cycles. In addition, this device can work well in a wide range of temperatures from −20 to 40 °C. The results demonstrate a proof-of-concept Na-DIB that avoids the challenges of conventional dual-graphite DIBs by utilizing non-graphite intercalation anode and cathode, and a carbonate-based electrolyte without any additives.We report a new sodium dual ion battery (Na-DIB) with conventional alkyl carbonate electrolyte by using graphene coated Na2Ti3O7 as the anode and coronene, a polycyclic aromatic hydrocarbon, as the cathode. Benefiting from the novel nano-structural features and intercalation mechanisms, the Na-DIB demonstrates high energy density and long cycling life.Download high-res image (210KB)Download full-size image
Co-reporter:Xiaodong Hao, Jie Wang, Bing Ding, Ya Wang, Zhi Chang, Hui Dou, Xiaogang Zhang
Journal of Power Sources 2017 Volume 352(Volume 352) pp:
Publication Date(Web):1 June 2017
DOI:10.1016/j.jpowsour.2017.03.088
•CN-BC was prepared by confine nanospace pyrolysis of bacterial cellulose.•The self-activation can lead to the development of surface area and porosity.•The interconnected carbon nanofibers exhibit large SSA and hierarchical porosity.•CN-BC shows excellent electrochemical properties for EDLCs.Bacterial cellulose (BC), a typical biomass prepared from the microbial fermentation process, has been proved that it can be an ideal platform for design of three-dimensional (3D) multifunctional nanomaterials in energy storage and conversion field. Here we developed a simple and general silica-assisted strategy for fabrication of interconnected 3D meso-microporous carbon nanofiber networks by confine nanospace pyrolysis of sustainable BC, which can be used as binder-free electrodes for high-performance supercapacitors. The synthesized carbon nanofibers exhibited the features of interconnected 3D networks architecture, large surface area (624 m2 g−1), mesopores-dominated hierarchical porosity, and high graphitization degree. The as-prepared electrode (CN-BC) displayed a maximum specific capacitance of 302 F g−1 at a current density of 0.5 A g−1, high-rate capability and good cyclicity in 6 M KOH electrolyte. This work, together with cost-effective preparation strategy to make high-value utilization of cheap biomass, should have significant implications in the green and mass-producible energy storage.Download high-res image (348KB)Download full-size image
Co-reporter:Shengyang Dong;Langyuan Wu;Junjun Wang;Ping Nie;Hui Dou
Journal of Materials Chemistry A 2017 vol. 5(Issue 12) pp:5806-5812
Publication Date(Web):2017/03/21
DOI:10.1039/C6TA11040A
There is an urgent need but it is still a huge challenge to integrate high energy and power density with high safety in a single energy storage device. Addressing this issue largely depends on design of new energy storage systems with novel electrode architectures. Herein, a novel electrochemical energy storage device called a quasi-solid-state Na-ion capacitor (QSS-NIC) is designed based on a 3D self-supported Na2Ti3O7 nanoribbon array/graphene foam (NTO/GF) anode and graphene foam (GF) cathode, and a Na-ion conducting gel polymer as the electrolyte and separator, without any binders, conducting additives or metal current collectors. Benefiting from the unique 3D self-supported cathode and anode, the GF//NTO/GF configuration achieves a high energy density of 70.6 W h kg−1 and high power density of 4000 W kg−1 on the basis of the mass of both electrodes, and a prominent cycling stability over 5000 cycles (capacitance retention ∼73.2%). This work successfully demonstrates a proof of concept of QSS-NIC as a high performance energy storage device based on two self-supported electrodes, which could provide a feasible approach to bridge the performance gap between capacitors and Na-ion batteries.
Co-reporter:Jie Wang;Ping Nie;Bing Ding;Shengyang Dong;Xiaodong Hao;Hui Dou
Journal of Materials Chemistry A 2017 vol. 5(Issue 6) pp:2411-2428
Publication Date(Web):2017/02/07
DOI:10.1039/C6TA08742F
Electrochemical energy storage devices are becoming increasingly more important for reducing fossil fuel energy consumption in transportation and for the widespread deployment of intermittent renewable energy. The applications of different energy storage devices in specific situations are all primarily reliant on the electrode materials, especially carbon materials. Biomass-derived carbon materials are receiving extensive attention as electrode materials for energy storage devices because of their tunable physical/chemical properties, environmental concern, and economic value. In this review, recent developments in the biomass-derived carbon materials and the properties controlling the mechanism behind their operation are presented and discussed. Moreover, progress on the applications of biomass-derived carbon materials as electrodes for energy storage devices is summarized, including electrochemical capacitors, lithium–sulfur batteries, lithium-ion batteries, and sodium-ion batteries. The effects of the pore structure, surface properties, and graphitic degree on the electrochemical performance are discussed in detail, which will guide further rational design of the biomass-derived carbon materials for energy storage devices.
Co-reporter:Guiyin Xu;Qing-bo Yan;Shitong Wang;Akihiro Kushima;Peng Bai;Kai Liu;Zilong Tang;Ju Li
Chemical Science (2010-Present) 2017 vol. 8(Issue 9) pp:6619-6625
Publication Date(Web):2017/08/21
DOI:10.1039/C7SC01961K
Lithium–sulfur batteries are one of the most promising next-generation batteries due to their high theoretical specific capacity, but are impeded by the low utilization of insulating sulfur, unstable morphology of the lithium metal anode, and transport of soluble polysulfides. Here, by coating a layer of nano titanium dioxide and carbon black onto a commercial polypropylene separator, we demonstrate a new composite separator that can confine the polysulfides on the cathode side, forming a catholyte chamber, and at the same time block the dendritic lithium on the anode side. Lithium–sulfur batteries using this separator show a high initial capacity of 1206 mA h g−1 and a low capacity decay rate of 0.1% per cycle at 0.5C. Analyses reveal the electrocatalytic effect and the excellent dendrite-blocking capability of the ∼7 µm thick coating.
Co-reporter:Guiyin Xu;Akihiro Kushima;Jiaren Yuan;Hui Dou;Weijiang Xue;Xiaohong Yan;Ju Li
Energy & Environmental Science (2008-Present) 2017 vol. 10(Issue 12) pp:2544-2551
Publication Date(Web):2017/12/06
DOI:10.1039/C7EE01898C
The performance of lithium–sulfur (Li–S) batteries is greatly improved by using acidized carbon nanotube paper (ACNTP) to induce in situ polymerization of ether-based DOL/DME liquid to grow an ion-selective solid barrier, to seal in soluble polysulfides on the cathode side. The Li–S battery with the in situ barrier showed an initial specific capacity of 683 mA h g−1 at a high current density of 1675 mA g−1, and maintained a discharge capacity of 454 mA h g−1 after 400 cycles. The capacity decay rate was 0.1% per cycle and a high Coulombic efficiency of 99% was achieved. Experimental characterizations and theoretical models demonstrate the in situ polymerized solid barrier stops sulfur transport while still allowing bidirectional Li+ transport, alleviating the shuttle effect and increasing the cycling performance. The soft and sticky nature of the solid electrolyte barrier makes it a good sealant, forming an enclosed catholyte chamber on the sulfur side.
Co-reporter:Hao Tong;Shihong Yue;Liang Lu;Fengqiao Jin;Qiwei Han;Jie Liu
Nanoscale (2009-Present) 2017 vol. 9(Issue 43) pp:16826-16835
Publication Date(Web):2017/11/09
DOI:10.1039/C7NR02498C
To increase the volumetric and gravimetric capacitances of supercapacitors, a new class of electrode materials with high electrochemical activity and favorable structures is extremely desired. In this work, a hollow novel nitrogen-doped 3D elastic single-walled carbon nanotube sponge (NSCS) which is ultra lightweight with the lowest density of 0.8 mg cm−3, and has a high open surface structure for electrolyte accessibility and excellent compressible properties as the electrode scaffold has been successfully fabricated by the pyrolysis method which could produce the carbon nanotube sponge easily on a large scale without high-cost and time-consuming processes. Moreover, a NiCo2O4 nanosheet supported on the NSCS has been successfully fabricated. The highest volumetric and gravimetric capacitance of this electrode is 790 F cm−3 at 1.43 g cm−3 and 1618 F g−1 at 0.54 g cm−3 with excellent cycling stability. The density of NiCo2O4/NSCS electrode was adjusted by mechanical compression and the most favorable density of the film for both high volumetric and gravimetric capacitances obtained was 1.21 g cm−3. The thick NiCo2O4/NSCS film of 72 μm has been fabricated at this favorable density, presenting both high volumetric and gravimetric capacitances of 597 F cm−3 and 1074 F g−1 at 1 A g−1, respectively, indicating that the structure of the NSCS is extremely feasible for obtaining a thick film electrode with excellent volumetric and gravimetric capacitances. Furthermore, an asymmetric supercapacitor of NiCo2O4/NSCS//NGN/CNTs was fabricated, exhibiting a high gravimetric energy density of 47.65 W h kg−1 at 536 W kg−1 and a volumetric energy density of 33.44 W h L−1 at 376.16 W L−1.
Co-reporter:Guiyin Xu, Ping Nie, Hui Dou, Bing Ding, Laiyang Li, Xiaogang Zhang
Materials Today 2017 Volume 20, Issue 4(Issue 4) pp:
Publication Date(Web):1 May 2017
DOI:10.1016/j.mattod.2016.10.003
High energy density batteries and high power density supercapacitors have attracted much attention because they are crucial to the power supply of future portable electronic devices, electric automobiles, unmanned aerial vehicles, etc. The electrode materials are key components for batteries and supercapacitors, which influence the practical energy and power density. Metal-organic frameworks possessing unique morphology, high specific surface area, functional linkers, and metal sites are excellent electrode materials for electrochemical energy storage devices. Herein, we review and comment on recent progress in metal-organic framework-based lithium-ion batteries, sodium-ion batteries, lithium-air batteries, lithium-sulfur/selenium batteries, and supercapacitors. Future perspectives and directions of metal-organic framework-based electrochemical energy storage devices are put forward on the basis of theoretical knowledge from the reported literature and our experimental experience.
Co-reporter:Hongsen Li, Lele Peng, Yue Zhu, Xiaogang Zhang, and Guihua Yu
Nano Letters 2016 Volume 16(Issue 9) pp:5938-5943
Publication Date(Web):August 8, 2016
DOI:10.1021/acs.nanolett.6b02932
Simultaneous integration of high-energy output with high-power delivery is a major challenge for electrochemical energy storage systems, limiting dual fine attributes on a device. We introduce a quasi-solid-state sodium ion capacitor (NIC) based on a battery type urchin-like Na2Ti3O7 anode and a capacitor type peanut shell derived carbon cathode, using a sodium ion conducting gel polymer as electrolyte, achieving high-energy-high-power characteristics in solid state. Energy densities can reach 111.2 Wh kg–1 at power density of 800 W kg–1, and 33.2 Wh kg–1 at power density of 11200 W kg–1, which are among the best reported state-of-the-art NICs. The designed device also exhibits long-term cycling stability over 3000 cycles with capacity retention ∼86%. Furthermore, we demonstrate the assembly of a highly flexible quasi-solid-state NIC and it shows no obvious capacity loss under different bending conditions.Keywords: conducting gel polymer; energy storage; high-energy density; high-power density; Sodium ion capacitor; solid-state;
Co-reporter:Shengyang Dong;Laifa Shen;Hongsen Li;Gang Pang;Hui Dou
Advanced Functional Materials 2016 Volume 26( Issue 21) pp:3703-3710
Publication Date(Web):
DOI:10.1002/adfm.201600264
Flexible energy storage devices are critical components for emerging flexible and wearable electronics. Improving the electrochemical performance of flexible energy storage devices depends largely on development of novel electrode architectures and new systems. Here, a new class of flexible energy storage device called flexible sodium-ion pseudocapacitors is developed based on 3D-flexible Na2Ti3O7 nanosheet arrays/carbon textiles (NTO/CT) as anode and flexible reduced graphene oxide film (GFs) as cathode without metal current collectors or conducting additives. The NTO/CT anode with advanced electrode architectures is fabricated by directly growing Na2Ti3O7 nanosheet arrays on carbon textiles with robust adhesion through a simple hydrothermal process. The flexible GF//NTO/CT configuration achieves a high energy density of 55 Wh kg−1 and high power density of 3000 W kg−1. Taking the fully packaged flexible sodium-ion pseudocapacitors into consideration, the maximum practical volumetric energy density and power density reach up to 1.3 mWh cm−3 and 70 mW cm−3, respectively. In addition, the flexible GF//NTO/CT device demonstrates a stable electrochemical performances with almost 100% capacitance retention under harsh mechanical deformation.
Co-reporter:Hongsen Li, Yue Zhu, Shengyang Dong, Laifa Shen, Zhijie Chen, Xiaogang Zhang, and Guihua Yu
Chemistry of Materials 2016 Volume 28(Issue 16) pp:5753
Publication Date(Web):August 1, 2016
DOI:10.1021/acs.chemmater.6b01988
Recently, hybrid ion capacitors which combine the characteristics of batteries and supercapacitors have gained great interests for large-scale energy storage applications. Here, we demonstrated a new hybrid sodium ion capacitor configuration, utilizing the niobium pentoxide (Nb2O5) and peanut shell carbon (PSC) as the anode and cathode materials, respectively. The advanced architecture of self-assembled Nb2O5 nanosheets with exceptional sodium ion storage property was obtained by carefully controlling reaction kinetics. A key finding is that the growth mechanism is demonstrated to be a process from one-dimensional nanorods to three-dimensional nanocubes, and further to two-dimensional nanosheets. The resulting Nb2O5 nanosheets//PSC hybrid capacitors deliver an exceptionally high energy density (43.2 Wh kg–1) and high power density (5760 W kg–1) based on the active materials, with a long and stable cycle life (capacity retention: ∼80% at 1280 mA g–1 after 3000 cycles).
Co-reporter:Hao Tong, Wenlong Bai, Shihong Yue, Zhenzhen Gao, Liang Lu, Laifa Shen, Shengyang Dong, Jiajia Zhu, Jianping He and Xiaogang Zhang
Journal of Materials Chemistry A 2016 vol. 4(Issue 29) pp:11256-11263
Publication Date(Web):08 Jun 2016
DOI:10.1039/C6TA02249A
To improve the energy density of supercapacitors, a new type of electrode material with high electrochemical activity and favorable morphology is extremely desired. Ternary metal sulfides with higher electrochemical capacity and activity than mono-metal sulfides hold great promise in the field of energy storage devices. Herein, an advanced electrode composed of zinc cobalt sulfide nanosheets supported on sandwich-like nitrogen-doped graphene/carbon nanotubes (NGN/CNTs) film has been successfully fabricated through a two-step synthesis. Benefiting from the characteristic features and 3D electrode architectures, the Zn0.76Co0.24S electrode exhibits a high specific capacitance of 2484 F g−1 at 2 A g−1 and excellent cycling stability (almost no capacitance fading after 10000 cycles at 30 A g−1). This creative nanostructure design of ternary transition metal sulfides could provide a promising prospect for application in energy storage devices. Moreover, an asymmetric supercapacitor was also fabricated by using Zn0.76Co0.24S/NGN/CNTs film as the positive electrode and NGN/CNTs film as the negative electrode, exhibiting a high energy density of 50.2 W h kg−1 at 387.5 W kg−1 and superior cycling stability of 100% initial capacity retention over 2000 cycles. This creative nanostructure design could provide a promising new way to develop high-performance supercapacitors and shed new light on configuring carbon-based ternary transition metal sulfide electrode materials in energy storage and conversion devices.
Co-reporter:Gaoliang Yang, Bing Ding, Jie Wang, Ping Nie, Hui Dou and Xiaogang Zhang
Nanoscale 2016 vol. 8(Issue 16) pp:8495-8499
Publication Date(Web):30 Mar 2016
DOI:10.1039/C6NR00409A
A porous nanowire material consisting of graphene–amorphous FePO4 was investigated as an advanced cathode material for sodium ion batteries for large-scale applications. This hybrid cathode material showed excellent cycling performance and superior rate capability, which were attributed to the porous nanowire structure and the existence of graphene.
Co-reporter:Bing Ding, Jie Wang, Ya Wang, Zhi Chang, Gang Pang, Hui Dou and Xiaogang Zhang
Nanoscale 2016 vol. 8(Issue 21) pp:11136-11142
Publication Date(Web):29 Apr 2016
DOI:10.1039/C6NR02155G
Two-dimensional (2D) carbon materials have attracted intense research interest for electrical double layer capacitors (EDLCs) due to their high aspect ratio and large surface area. Herein, we propose an exfoliation–chlorination route for preparing ultrathin carbon nanosheets by using ternary layered carbide Ti3AlC2 as the precursor. Due to the large intersheet space of exfoliated layered carbide (MXene), the as-prepared carbon nanosheets exhibit a thickness of 3–4 nm and a large specific surface area of 1766 m2 g−1 with hierarchical porosity. These features significantly improve the ion-accessible surface area for charge storage and shorten the ion transport length in the thin dimension. As a result, the carbon nanosheets show a high specific capacitance (220 F g−1 at 0.5 A g−1), remarkable high power capability (79% capacitance retention at 20 A g−1) when measured in a symmetrical two-electrode configuration in an aqueous electrolyte. The method described in this work provides a new route to prepare 2D electrode materials from a bulk precursor, thus exploiting their full potential for EDLCs.
Co-reporter:Jie Wang, Bing Ding, Xiaodong Hao, Yunling Xu, Ya Wang, Laifa Shen, Hui Dou, Xiaogang Zhang
Carbon 2016 Volume 102() pp:255-261
Publication Date(Web):June 2016
DOI:10.1016/j.carbon.2016.02.047
Graphene is known to suffer from severe aggregation and incomplete recovery of a π–π conjugated system during the reduction process from graphene oxide. Here we report that these issues can be addressed by using a modified molten salt system. The advantages of the molten salt for reducing graphene show in three aspects: (i) prevent restacking; (ii) restore the conjugated network; (iii) serve as reaction medium for KNO3 activation and nitrogen doping. The molten-salt method-derived graphene (MNG) displays a highly sp2–hybrid constitution, nitrogen doping and hierarchically porous structure. With this design, the MNG–based supercapacitor manifests outstanding specific capacitance (234 F g−1 and 130 F g−1 in 6 M KOH and EMIMBF4 electrolyte, respectively), high power density, combined with excellent cycling stability and low self-discharge rate. The facile and scalable features of this strategy will be helpful for the rational design of functionalized graphene-based materials for diverse applications.
Co-reporter:Jingjie Wang, Hongsen Li, Laifa Shen, Shengyang Dong and Xiaogang Zhang
RSC Advances 2016 vol. 6(Issue 75) pp:71338-71344
Publication Date(Web):12 Jul 2016
DOI:10.1039/C6RA11460A
Lithium ion capacitors (LICs), which have high energy density and power density and benefit from the combination of the merits of batteries and supercapacitors, have been attracted tremendous attention. The sluggish faradaic battery anode is a big challenge for the development of high-performance LICs. In this study, an Nb2O5/ordered mesoporous carbon (CMK-3) nanocomposite has been synthesized via the nanocasting technology using CMK-3 as the hard template and NbCl5 as the precursor. The Nb2O5/CMK-3 electrode exhibits significantly enhanced electrochemical performance in terms of specific capacity, rate capability and cyclic stability when compared with bulk Nb2O5. Furthermore, a high performance LIC composed of the Nb2O5/CMK-3 nanocomposite as the anode and activated carbon derived from peanut shell as the cathode was constructed, which exhibits a high energy density of 43.9 W h kg−1 (at a power density of 87.5 W kg−1) and high power density of 8750 W kg−1 (at an energy density of 24.4 W h kg−1). Such outstanding performance mainly stems from the synergic effects between the mesoporous carbon matrices and the well-dispersed active material nanoparticles, which increase electronic conductivity and the reactivity of Nb2O5.
Co-reporter:Bing Ding, Zhi Chang, Jie Wang, Hui Dou and Xiaogang Zhang
RSC Advances 2016 vol. 6(Issue 53) pp:47858-47863
Publication Date(Web):29 Apr 2016
DOI:10.1039/C6RA08104E
Lithium–sulfur (Li–S) batteries are receiving intense interest because of their high theoretical energy density and low cost. However, the rapid capacity fading is a significant problem facing the application of Li–S batteries. Herein, we describe an in situ confinement strategy for preparing a porous poly(3,4-ethylenedioxythiophene)/sulfur (pPEDOT/S) composite for Li–S batteries. The as-prepared pPEDOT/S composite exhibits a monodispersed nanostructure with sizes in the range of 400–600 nm. The pPEDOT/S composite electrode exhibits excellent cycling stability and high specific capacity. At a current rate of 0.5C, the pPEDOT/S electrode exhibits a high specific capacity of 883 mA h g−1 and a capacity retention of 71% after 200 cycles. During the charge/discharge process, the porous nanostructure could facilitate rapid electrolyte diffusion and accommodate the volumetric expansion. The chemical interaction between the PEDOT and polysulfides and discharged products could efficiently avoid the dissolution of polysulfides and the irreversible deposition of discharged products. The unique nanostructure plus the excellent electrochemical performances of the composites described in the current study allow for new opportunities to design high-performance electrodes for Li–S batteries.
Co-reporter:Liang Hao, Jie Wang, Laifa Shen, Jiajia Zhu, Bing Ding and Xiaogang Zhang
RSC Advances 2016 vol. 6(Issue 30) pp:25056-25061
Publication Date(Web):01 Mar 2016
DOI:10.1039/C5RA22520E
Mixed-valence vanadium oxide (VOx)/ordered mesoporous carbon (CMK-3) composite (VOC) were synthesized through a facile liquid-phase method followed by calcination. The microstructures of the composite were characterized by X-ray diffraction (XRD), nitrogen adsorption and desorption, X-ray photoelectron spectra (XPS), scanning election microscopy (SEM) and transmission election microscopy (TEM). The relevant results showed that vanadium oxide nanoparticles with mixed valence were successfully embedded in mesoporous channels in the conductive matrix and dispersed on the CMK-3 surface to form the interwoven composite. The introduction of the CMK-3 framework not only improves electron transfer but also prevents the structure collapsing during cycling. As expected, the composite exhibits excellent electrochemical properties. It delivered a specific capacitance of 257 F g−1 at 0.5 A g−1 and maintained 77.3% at 8 A g−1 in 5 M LiNO3. After 5000 cycles, the capacitance only decreased 20%.
Co-reporter:Liang Hao, Laifa Shen, Jie Wang, Yunling Xu and Xiaogang Zhang
RSC Advances 2016 vol. 6(Issue 12) pp:9950-9957
Publication Date(Web):15 Jan 2016
DOI:10.1039/C5RA24068A
Although supercapacitors possess a fast charge/discharge capability, the practical application of supercapacitors is still hindered largely by their low energy density. Improving the electrochemical performance of supercapacitors depends largely on the development of novel electrode materials and hybrid systems. In this work, hollow NiCo2S4 nanotube arrays are successfully grown on carbon textile (CT) with robust adhesion through a two-step synthesis, involving the growth of a solid nanowire precursor and subsequent conversion into NiCo2S4 nanotubes using a sulfidation process. Using CT-supported NiCo2S4 nanotube arrays as the positive electrode and activated carbon as the negative electrode, a high-performance asymmetric supercapacitor with a maximum voltage of 1.6 V has been fabricated, which manifests high energy density (∼40.1 W h kg−1 at 451 W kg−1), high power density (∼4725 W kg−1 at 21 W h kg−1) and excellent cyclability.
Co-reporter:Xiangjun Lu, Hui Dou, Xiaogang Zhang
Materials Letters 2016 Volume 178() pp:304-307
Publication Date(Web):1 September 2016
DOI:10.1016/j.matlet.2016.05.029
•The flexible GN/MCS film is prepared through a flow-assembly method.•The presence of MCS effectively prevents the restacking of GN sheets.•The GN/MCS has a specific capacitance of 211 F g−1.•The specific capacitance decreases only 4% after 5000 cycles.A flexible graphene (GN)-based film has been prepared by flow-directed assembly from a complex dispersion of GN and mesoporous carbon nanosphere (MCS) functionalized with poly dimethyl diallyl ammonium chloride. Morphology analysis displays that the presence of MCS has effectively prevent the restacking of individual GN sheets, favoring electrolyte ions easier access to the surfaces of GNs in forming electric double-layers. In application as a supercapacitor in 1 M KOH electrolyte, GN/MCS film shows superior electrochemical performance, including high specific capacitance (211 F g−1 at 0.2 A g−1), good rate capability (61% capacity retention at 20 A g−1) and excellent electrochemical stability (4% capacity loss after 5000 cycles).
Co-reporter:Bing Ding;Jie Wang;Zhi Chang;Guiyin Xu;Xiaodong Hao;Dr. Laifa Shen; Hui Dou ; Xiaogang Zhang
ChemElectroChem 2016 Volume 3( Issue 4) pp:668-674
Publication Date(Web):
DOI:10.1002/celc.201500536
Abstract
Metal–organic framework (MOF)-derived carbon materials exhibit large surface areas, but dominant micropore characteristics and uncontrollable dimensions. Herein, we propose a self-sacrificial template-directed synthesis method to engineer the porous structure and dimensions of MOF-derived carbon materials. A porous zinc oxide (ZnO) nanosheet solid is selected as the self-sacrificial template and two-dimensional (2D) nanostructure-directing agent to prepare 2D ZIF-8-derived carbon nanosheets (ZCNs). The as-prepared ZCN materials exhibit a large surface area with hierarchical porosity. These intriguing features render ZCN materials advanced electrode materials for electrochemical energy-storage devices, demonstrating large ion-accessible surface area and high ion-/electron-transport rates. This self-sacrificial template-directed synthesis method offers new avenues for rational engineering of the porous structure and dimensions of MOF-derived porous carbon materials, thus exploiting their full potential for electrochemical energy-storage devices.
Co-reporter:Jie Wang, Jing Tang, Yunling Xu, Bing Ding, Zhi Chang, Ya Wang, Xiaodong Hao, Hui Dou, Jung Ho Kim, Xiaogang Zhang, Yusuke Yamauchi
Nano Energy 2016 Volume 28() pp:232-240
Publication Date(Web):October 2016
DOI:10.1016/j.nanoen.2016.08.043
•Double-capillary carbon nanofibers were prepared through coaxial electrospinning.•Interface miscibility was utilized to create hierarchically porosity.•Flexible supercapacitor with high performance was achieved.The preparation of free-standing electrode materials with high specific capacitance and flexibility is very important for the production of flexible electric double layer capacitors. There is a great incompatibility, however, between the flexibility and the porosity of the electrode material. In this work, by using coaxial electrospinning, we propose an interface miscibility induced approach to the design of double-capillary carbon nanofibers (DCNF) with micropores in the inner capillary and mesopores in the outer capillary. The unique structure achieves synergism between high accessibility to electrolyte, a short diffusion length for ions, high conductivity, and high flexibility. The DCNFs can be directly used as electrodes to assemble flexible supercapacitors, which show a high gravimetric capacitance of 133 F g−1 and excellent high-rate performance in ionic liquid electrolyte. The maximum energy density and power density reach 56.6 Wh kg−1 and 114 kW kg−1, respectively. The combination of scalable coaxial electrospinning technology and supercapacitors with excellent performance may pave the way to wearable and safe electronics.Flexible carbon nanofibers with double-capillary structure, which combines micropores in the inner capillary and mesopores in the outer capillary, were designed. The assembled supercapacitor showcases high energy densities and long cycle life in ionic liquid electrolyte.
Co-reporter:Laifa Shen;Jie Wang;Guiyin Xu;Hongsen Li;Hui Dou
Advanced Energy Materials 2015 Volume 5( Issue 3) pp:
Publication Date(Web):
DOI:10.1002/aenm.201400977
To push the energy density limit of supercapacitors, a new class of electrode materials with favorable architectures is strongly needed. Binary metal sulfides hold great promise as an electrode material for high-performance energy storage devices because they offer higher electrochemical activity and higher capacity than mono-metal sulfides. Here, the rational design and fabrication of NiCo2S4 nanosheets supported on nitrogen-doped carbon foams (NCF) is presented as a novel flexible electrode for supercapacitors. A facile two-step method is developed for growth of NiCo2S4 nanosheets on NCF with robust adhesion, involving the growth of Ni-Co precursor and subsequent conversion into NiCo2S4 nanosheets through sulfidation process. Benefiting from the compositional features and 3D electrode architectures, the NiCo2S4/NCF electrode exhibits greatly improved electrochemical performance with ultrahigh capacitance (877 F g−1 at 20 A g−1) and excellent cycling stability. Moreover, a binder-free asymmetric supercapacitor device is also fabricated by using NiCo2S4/NCF as the positive electrode and ordered mesoporous carbon (OMC)/NCF as the negative electrode; this demonstrates high energy density (≈45.5 Wh kg−1 at 512 W kg−1).
Co-reporter:Hongsen Li, Laifa Shen, Gang Pang, Shan Fang, Haifeng Luo, Kai Yang and Xiaogang Zhang
Nanoscale 2015 vol. 7(Issue 2) pp:619-624
Publication Date(Web):23 Oct 2014
DOI:10.1039/C4NR04847D
As a competitor for Li4Ti5O12 with a higher capacity and extreme safety, monoclinic TiNb2O7 has been considered as a promising anode material for next-generation high power lithium ion batteries. However, TiNb2O7 suffers from low electronic conductivity and ionic conductivity, which restricts the electrochemical kinetics. Herein, a facile and advanced architecture design of hierarchical TiNb2O7 microspheres is successfully developed for large-scale preparation without any surfactant assistance. To the best of our knowledge, this is the first report on the one step solvothermal synthesis of TiNb2O7 microspheres with micro- and nano-scale composite structures. When evaluated as an anode material for lithium ion batteries, the electrode exhibits excellent high rate capacities and ultra-long cyclability, such as 258 mA h g−1 at 1 C, 175 mA h g−1 at 5 C, and 138 mA h g−1 at 10 C, extending to more than 500 cycles.
Co-reporter:Shan Fang, Laifa Shen, Zhenkun Tong, Hao Zheng, Fang Zhang and Xiaogang Zhang
Nanoscale 2015 vol. 7(Issue 16) pp:7409-7414
Publication Date(Web):20 Mar 2015
DOI:10.1039/C5NR00132C
Silicon has a large specific capacity which is an order of magnitude beyond that of conventional graphite, making it a promising anode material for lithium ion batteries. However, the large volume changes (∼300%) during cycling caused material pulverization and instability of the solid–electrolyte interphase resulting in poor cyclability which prevented its commercial application. Here, we have prepared a novel one-dimensional core–shell nanostructure in which the Si nanoparticles have been confined within hollow carbon nanofibres. Such a unique nanostructure exhibits high conductivity and facile ion transport, and the uniform pores within the particles which are generated during magnesiothermic reduction can serve as a buffer zone to accommodate the large volume changes of Si during electrochemical lithiation. Owing to these advantages, the composite shows high rate performance and good cycling stability. The optimum design of the core–shell nanostructure shows promise for the synthesis of a variety of high-performance electrode materials.
Co-reporter:Laiyang Li, Laifa Shen, Ping Nie, Gang Pang, Jie Wang, Hongsen Li, Shengyang Dong and Xiaogang Zhang
Journal of Materials Chemistry A 2015 vol. 3(Issue 48) pp:24309-24314
Publication Date(Web):2015/11/02
DOI:10.1039/C5TA07856C
Porous NiCo2O4 nanotubes have been successfully synthesized using a facile and cost-effective electrospinning method and used as a noble-metal-free catalyst for rechargeable Li–O2 batteries. The as-synthesized NiCo2O4 nanotubes possess hollow cavities and porous walls, and were found to significantly improve the electrochemical performance of Li–O2 batteries, by endowing them with a high initial discharge capacity, reduced overpotential as well as good rate capability. Excellent cycling stability over 110 cycles with a highly discharged voltage platform of 2.4 V at 200 mA gc−1 was achieved. By means of FESEM, XRD, Raman spectroscopy and GITT analysis, toroidal-shaped Li2O2 particles were identified as the dominant discharge product and it was revealed that the Li2O2 can be completely decomposed during the charging process, indicating its superior reversibility as an effective bifunctional catalyst for Li–O2 batteries. All the results indicated that the porous NiCo2O4 nanotubes expressed intriguing properties and great potential applications as a noble-metal-free effective bifunctional catalyst for rechargeable Li–O2 batteries.
Co-reporter:Wenlong Bai, Hao Tong, Zhenzhen Gao, Shihong Yue, Sichuan Xing, Shengyang Dong, Laifa Shen, Jianping He, Xiaogang Zhang and Yanyu Liang
Journal of Materials Chemistry A 2015 vol. 3(Issue 43) pp:21891-21898
Publication Date(Web):10 Sep 2015
DOI:10.1039/C5TA05798A
Homogeneous ZnCo2O4 nanoflowers have been synthesized on a 3D layered structure of carbon nanotubes/nitrogen-doped graphene (NGN/CNTs) film by a hydrothermal process and subsequent calcination method. The ZnCo2O4 nanoflowers have an average diameter of 4 μm, and are composed of petals less than 100 nanometers. The as-synthesized ZnCo2O4/NGN/CNT film can be directly used as a flexible electrode with a high specific capacitance of 1802 F g−1 at 1 A g−1 and excellent cycling stability (almost 0% fade after 4000 sustaining charge/discharge at 10 A g−1). These results suggest that the obtained electrode has a promising application prospect in flexible energy conversion/storage devices. In addition, a binder-free asymmetric supercapacitor has been synthesized with the ZnCo2O4/NGN/CNT film as the positive electrode and the NGN/CNT film as the negative electrode. This demonstrates superior energy density (≈37.19 W h kg−1 at 750 W kg−1) and power density (≈14.992 kW kg−1 at 14.16 W h kg−1).
Co-reporter:Shengyang Dong, Laifa Shen, Hongsen Li, Ping Nie, Yaoyao Zhu, Qi Sheng and Xiaogang Zhang
Journal of Materials Chemistry A 2015 vol. 3(Issue 42) pp:21277-21283
Publication Date(Web):09 Sep 2015
DOI:10.1039/C5TA05714K
Hybrid sodium-ion capacitors (NICs) have tremendous potential in large-scale energy storage applications due to their low cost, long lifetime and high power. However, it remains a great challenge to find a desirable anode material with fast kinetics and superior cycle life. Here an applicable strategy to in situ grow Na2Ti3O7 on 1D CNTs as an anode material for sodium-ion capacitors is presented. Benefiting from the unique 1D nanostructure and the presence of pseudocapacitive charge storage mechanism, the Na2Ti3O7@CNT electrode exhibits excellent electrochemical performance with high rate capability and superb cycling stability. Moreover, a high performance hybrid NIC is also fabricated by using Na2Ti3O7@CNTs as an anode and activated carbon derived from the outer peanut shell as a cathode, which delivers high energy density (58.5 W h kg−1), high power density (3000 W kg−1), and long term cycle life (retaining ca. 75% of its original capacity at 0.4 A g−1 after 4000 cycles).
Co-reporter:Ping Nie, Laifa Shen, Gang Pang, Yaoyao Zhu, Guiyin Xu, Yunhua Qing, Hui Dou and Xiaogang Zhang
Journal of Materials Chemistry A 2015 vol. 3(Issue 32) pp:16590-16597
Publication Date(Web):10 Jul 2015
DOI:10.1039/C5TA03197D
In response to the ever-increasing demand for grid-scale energy storage systems, sodium ion batteries (SIBs) working at ambient- or room-temperature are gaining much attention as promising alternatives because of the abundance and low cost of sodium resources. However, their adoption is significantly hampered by several issues, especially in terms of sluggish kinetics and capacity retention during cycling. Herein, flexible Prussian blue analogue FeFe(CN)6/carbon cloth composites are synthesized using low temperature strategies and utilized as a potential host for sodium ion insertion. As a proof of concept, the composites demonstrate excellent electrochemical performance: a reversible specific capacity of 82 mA h g−1 at 0.2C, good rate capability and long term cycling life with 81.2% capacity retention over 1000 cycles. Most significantly, this low-cost, scalable and low-temperature synthesis provides guidance for the design of other flexible materials that could have applications in wearable electronics, energy storage and conversion devices.
Co-reporter:Hao Zheng, Shan Fang, Zhenkun Tong, Gang Pang, Laifa Shen, Hongsen Li, Liang Yang and Xiaogang Zhang
Journal of Materials Chemistry A 2015 vol. 3(Issue 23) pp:12476-12481
Publication Date(Web):06 May 2015
DOI:10.1039/C5TA02259B
In this work, TiN NW supported silicon nanorods (TiN@Si NRs) are produced via direct radio frequency (RF) magnetron sputtering of Si deposition onto the surface of TiN NWs. Due to its superior mechanical stability and electrical conductivity, TiN provides more stable support and better conductive pathways for Si when compared with TiO2. The unique core–shell TiN@Si NR structure has enough void space to accommodate the large volume changes of Si during charge/discharge cycling. The novel 3D architecture electrode demonstrates exceptional electrochemical performances with ultrahigh specific capacity. Comparing with TiO2@Si NRs, TiN@Si NR electrodes exhibit improved cycling performances, which can still retain a capacity of 3258.8 mA h g−1 after 200 cycles at 1 A g−1. It should be noted that the TiN@Si NRs show an excellent rate performance even at a high current density (2256.6 mA h g−1 is realized at 10 A g−1). These results endow the electrodes with high power and long cycling stability.
Co-reporter:Jie Wang, Laifa Shen, Ping Nie, Xiaoliang Yun, Yunling Xu, Hui Dou and Xiaogang Zhang
Journal of Materials Chemistry A 2015 vol. 3(Issue 6) pp:2853-2860
Publication Date(Web):12 Dec 2014
DOI:10.1039/C4TA05932H
Improving the electrochemical performance of supercapacitors mainly depends on the electrode design and system construction. A new kind of additive-free asymmetric supercapacitors (ASCs) has been successfully fabricated using a self-supported carbon foam/ordered mesoporous carbon (CF-OMC) film as the negative electrode and free-standing CF-NiCo2O4 nanosheets (NSs) as the positive electrode, respectively. The highly conductive three-dimensional (3D) CF framework could facilitate electron transfer while the porous thin film of OMC and ultrathin NiCo2O4 nanosheets could shorten the ion diffusion path and facilitate the rapid migration of electrolyte ions. The optimized asymmetric supercapacitors could work with an operational voltage of 1.6 V, delivering a high energy density (∼47.8 W h kg−1), high power density (∼9800 W kg−1 at 17.7 W h kg−1) and outstanding cycle stability (∼10000 times). This research may pave the way for fabricating lightweight, low-cost, and high-performance electrodes for energy storage applications.
Co-reporter:Shan Fang, Laifa Shen, Hao Zheng and Xiaogang Zhang
Journal of Materials Chemistry A 2015 vol. 3(Issue 4) pp:1498-1503
Publication Date(Web):14 Nov 2014
DOI:10.1039/C4TA04350B
A Ge–graphene–carbon nanotube composite electrode was constructed by germanium (Ge) nanoparticles anchored on reduced graphene oxide (Ge–RGO) intertwined with carbon nanotubes (CNT). In this unique structure, the graphene sheets improve the electrical conductivity and buffer severe volume changes. Additionally, the CNT mechanically binds together with Ge–RGO to maintain the integrity of the electrodes and stabilize the electric conductive network for the active Ge nanoparticles, leading to better cycling performance. As a result, the designed anode exhibits an outstanding energy capacity up to 863.8 mA h g−1 at a current density of 100 mA g−1 after 100 cycles and good rate performances of 1181.7, 1073.8, 1005.2, 872.0, 767.6, and 644.8 mA h g−1 at current densities of 100, 200, 400, 800, 1600, and 3200 mA g−1, respectively. Our results indicate that the hybrids exhibit considerably improved lithium storage performance.
Co-reporter:Hongsen Li, Laifa Shen, Jie Wang, Shan Fang, Yingxia Zhang, Hui Dou and Xiaogang Zhang
Journal of Materials Chemistry A 2015 vol. 3(Issue 32) pp:16785-16790
Publication Date(Web):10 Jul 2015
DOI:10.1039/C5TA02929E
Hybrid supercapacitors are a very appealing power source with high energy density and power density because they employ both the merits of lithium ion batteries and supercapacitors. To balance such hybrid systems, the rate of the redox component must be substantially comparative to the levels of the double layer process. As far as the insertion-host material TiNb2O7 is concerned, we have used facile step electrode design consisting of the physically assisted template infusion of Ti–Nb sol into the pores of AAO followed by in situ conversion into porous TiNb2O7 nanotubes within the AAO walls under calcination, and finally making those templates dissolve away. Using such an electrode as the battery type anode and a graphene grass electrode as the capacitor type cathode, we successfully constructed a novel hybrid supercapacitor. Within a voltage range of 0–3 V, a high energy density of ∼74 W h kg−1 is achieved and it could remain as much as ∼34.5 W h kg−1 at a power of 7500 W kg−1. The present research sheds new light on the development of energy storage devices with both high energy density and high power density.
Co-reporter:Jie Wang, Laifa Shen, Yunling Xu, Hui Dou and Xiaogang Zhang
New Journal of Chemistry 2015 vol. 39(Issue 12) pp:9497-9503
Publication Date(Web):23 Sep 2015
DOI:10.1039/C5NJ02080H
As electrical energy storage and delivery devices, carbon-based supercapacitors have attracted much attention for advancing the energy-efficient economy. It is important to develop a facile, low-cost and environmentally friendly method of producing novel carbon materials. In this study, we report a scalable synthesis of phosphorus- and nitrogen-co-doped porous carbons using lamellar-structured fish scale. The special lamellar structure of fish scale allows the production of porous carbons with large specific surface areas (up to 1300 m2 g−1) and a high level of mesoporosity. Their inherent organic composition could be adapted with abundant N and P functional groups on the final carbons. Their high levels of porosity and rich surface functionality permit the carbons to exhibit excellent electrochemical performance as electrode materials for supercapacitors. The energy densities of supercapacitors approach 11.7 and 33.1 W h kg−1 in aqueous and IL electrolytes, respectively.
Co-reporter:Shan Fang, Laifa Shen, Hao Zheng, Zhenkun Tong, Gang Pang and Xiaogang Zhang
RSC Advances 2015 vol. 5(Issue 104) pp:85256-85263
Publication Date(Web):28 Sep 2015
DOI:10.1039/C5RA17432E
In this study, a relatively simple and direct method is used to prepare germanium nanoparticles (Ge NPs) embedded in the pore tunnels of an N-doped mesoporous carbon matrix. In the Ge/CMK-3 nanocomposite, the highly ordered porous structure and large pore volume guarantee a sufficient Ge loading and buffer the large volume changes of Ge during the discharge/charge cycles. More specifically, the mesoporous carbon matrix can supply sufficient pathways for Li+ and electron transport to the encapsulated nanometer-sized Ge, as well as restrain the agglomeration and growth of Ge during the crystallization process. Accordingly, the electrode of Ge/CMK-3 attained a capacity as high as 755.7 mA h g−1 at 500 mA g−1 after 420 cycles with a capacity retention of 93.3% based on the 11th cycle. The study shows that the electrochemical properties of Ge/CMK-3 are significantly improved compared to that of the bulk Ge anode, and it demonstrates that Ge/CMK-3 could potentially show promise as an anode material for energy storage.
Co-reporter:Shengyang Dong, Xiaoyan Wang, Laifa Shen, Hongsen Li, Jie Wang, Ping Nie, Jingjie Wang, Xiaogang Zhang
Journal of Electroanalytical Chemistry 2015 Volume 757() pp:1-7
Publication Date(Web):15 November 2015
DOI:10.1016/j.jelechem.2015.09.002
•Ti3 + self-doped Li4Ti5O12 was synthesized by a new strategy without use of any additional reducing reagents.•The introduction of Ti3 + improved the rate capability and cycle stability of Li4Ti5O12 electrode.•A high performance lithium-ion capacitor was fabricated by using Ti3 + self-doped Li4Ti5O12 as an insertion-type anode.To enhance kinetics of lithium insertion/extraction of anode materials for hybrid lithium-ion capacitors (hybrid LICs), we develop a new applicable strategy toward the synthesis of trivalent Ti self-doped Li4Ti5O12 nanoparticles. Starting with Ti2O3, we show that subsequent solid state reaction with Li2CO3 leads to the formation of trivalent Ti self-doped Li4Ti5O12. The presence of trivalent Ti gives rise to high electric conductivity and the nanostructure reduces the transport path lengths of lithium-ions and electrons, permitting fast kinetics for both transported lithium-ions and electrons, thus enabling high-power performance. A high performance hybrid LIC is fabricated by using Ti3 + self-doped Li4Ti5O12 as an insertion-type anode and activated carbon derived from outer peanut shell as cathode, which delivers high energy density (67 Wh kg− 1), high power density (8000 W kg− 1). Additionally, the device still retains about 79% of its original capacity even after 5000 cycles at 0.5 A g− 1.
Co-reporter:Hongsen Li, Laifa Shen, Bing Ding, Gang Pang, Hui Dou, Xiaogang Zhang
Nano Energy 2015 Volume 13() pp:18-27
Publication Date(Web):April 2015
DOI:10.1016/j.nanoen.2015.02.002
•Ultralong SrLi2Ti6O14 nanowires composed of single-crystalline nanoparticles.•Unique “nano-bead-chain” nanoparticle-in-nanowire architecture.•Excellent high-rate performance with long stability.•Li-storage mechanism revealed by XPS and XANES.To deploy Li-ion batteries for large scale application, it is essential to develop durable electrodes with high power and energy density. Here, we demonstrate that ultralong SrLi2Ti6O14 nanowires anode materials synthesized by a simple electrospinning technique are capable of excellent high-rate performance with long stability. The SrLi2Ti6O14 nanowires composed of single-crystalline nanoparticles possess the features of “nano-bead-chain” architecture. Used as anode material for lithium ions batteries, the novel SrLi2Ti6O14 nanowires exhibits a high reversible capacity of 171.4 mA h g−1 at 0.1 C and retains 96.2 mA h g−1 even at high rate of 20 C. In addition, the capacity is able to stabilize at 101 mA h g−1 after 1000 cycles, corresponding to 0.0086% capacity fading per cycle. Importantly, the Li-storage mechanism of Li2SrTi6O14 was revealed by X-ray photoelectron spectroscopy (XPS) and X-ray absorption near edge structure (XANES). The greatly improved electrochemical performance arises from the favorable kinetics properties stemming from unique nanoparticle-in-nanowire one-dimensional architecture.Ultralong SrLi2Ti6O14 nanowires are reported as a promising candidate for high power lithium ion batteries. The Li-storage mechanism of SrLi2Ti6O14 was revealed by X-ray photoelectron spectroscopy (XPS) and X-ray absorption near edge structure (XANES). Owning to the unique “nano-bead-chain” nanoparticle-in-nanowire architecture, the SrLi2Ti6O14 nanowires possessing favorable kinetics properties give rise to outstanding electrochemical performances including high capacity, excellent rate capability, high safety, and long lifespan.
Co-reporter:Yunling Xu;Dr. Jie Wang;Bing Ding;Laifa Shen; Hui Dou ; Xiaogang Zhang
ChemElectroChem 2015 Volume 2( Issue 12) pp:2020-2026
Publication Date(Web):
DOI:10.1002/celc.201500310
Abstract
In this work, ternary metal nitrides are proposed as novel electrode materials for supercapacitors. We selectively fabricate ternary vanadium titanium nitride/carbon (VTiN/C) nanofibers through a facile electrospinning strategy and investigate their electrochemical performance for the first time. The obtained well-interconnected VTiN/C nanofibers with VTiN nanoparticles embedded into carbon ensure rapid electron/ion transfer and offer a highly ion-accessible surface. Appealingly, the VTiN-4/C nanofibers exhibit a greatly improved performance, with a high specific capacitance (430.7 F g−1, 0.5 A g−1) and a good rate capability. Furthermore, the performance of the VTiN/C nanofibers is found to be controllable by adjusting the V/Ti atomic ratio. The encouraging electrochemical performance suggests that ternary VTiN could be a promising electrode material for supercapacitors.
Co-reporter:Haifeng Luo;Ping Nie;Laifa Shen;Hongshen Li;Haifu Deng;Yaoyao Zhu ;Dr. Xiaogang Zhang
ChemElectroChem 2015 Volume 2( Issue 1) pp:127-133
Publication Date(Web):
DOI:10.1002/celc.201402256
Abstract
High-voltage LiNi0.5Mn1.5O4 hollow microspheres have been synthesized through a facile solid-state method. X-ray diffraction and scanning electron microscopy results reveal that the as-prepared LiNi0.5Mn1.5O4 microspheres are constructed with nanometer-sized primary particles. The effects of the precursors on the morphologies and electrochemical properties of LiNi0.5Mn1.5O4 materials are systematically investigated. Electrochemical test results demonstrate that the materials with large porosity and smaller second particles exhibit higher reversible capacity as well as better cycle stability and rate capacities. LiNi0.5Mn1.5O4 prepared from MnCO3 precursors delivers high reversible capacities of 135.5, 147.5, and 132.1 mAh g−1 at 0.1, 0.5, and 2 C, respectively. Even at a high rate of 5 C, the electrode retains 93.4 % of the initial capacity at 0.1 C. Moreover, the electrode shows excellent cycle stability with a discharge capacity of 110 mAh g−1 at 1 C after 80 cycles at elevated temperature. The extremely attractive electrochemical properties are closely related to the unique structure and chemistry of the synthesized material.
Co-reporter:Laifa Shen;Qian Che;Hongsen Li
Advanced Functional Materials 2014 Volume 24( Issue 18) pp:2630-2637
Publication Date(Web):
DOI:10.1002/adfm.201303138
Binary metal oxides has been regarded as a promising class of electrode materials for high-performance energy storage devices since it offers higher electrochemical activity and higher capacity than mono-metal oxide. Besides, rational design of electrode architectures is an effective solution to further enhance electrochemical performance of energy storage devices. Here, the advanced electrode architectures consisting of carbon textiles uniformally covered by mesoporous NiCo2O4 nanowire arrays (NWAs) are successfully fabricated by a simple surfactant-assisted hydrothermal method combined with a short post annealing treatment, which can be directly applied as self-supported electrodes for energy storage devices, such as Li-ion batteries, supercapacitors. The as-prepared mesoporous NiCo2O4 nanowires consist of numerous highly crystalline nanoparticles, leaving a large number of mesopores to alleviate the volume change during the charge/discharge process. Electrode architectures presented here promise fast electron transport by direct connection to the growth substrate and facile ion diffusion path provided by both the abundant mesoporous structure in nanowires and large open spaces between neighboring nanowires, which ensures every nanowire participates in the ultrafast electrochemical reaction. Benefiting from the intrinsic materials and architectures features, the unique binder-free NiCo2O4/carbon textiles exhibit high specific capacity/capacitance, excellent rate capability, and cycling stability.
Co-reporter:Shan Fang, Laifa Shen, Guiyin Xu, Ping Nie, Jie Wang, Hui Dou, and Xiaogang Zhang
ACS Applied Materials & Interfaces 2014 Volume 6(Issue 9) pp:6497
Publication Date(Web):April 8, 2014
DOI:10.1021/am500066j
A unique core–shell structure of silicon@titania (Si@TiO2) composite with silicon nanoparticles encapsulated in TiO2 hollow spheres is synthesized by a simple hydrolysis method combined with magnesiothermic reduction method. It is found that the TiO2 shell is effective for improving the electrical conductivity and structural stability. More importantly, the well-designed nanostructure with enough empty space would accommodate the volume change of silicon during the cycling. Reversible capacities of 1911.1 and 795 mAh g–1 can be obtained at 0.05 C and a high current rate of 1 C, respectively. After 100 cycles at 0.1 C, the composite electrode still maintains a high capacity of 804 mAh g–1. This excellent cycling stability and high-rate capability can be ascribed to the unique core–shell nanostructure and the synergistic effect between Si and TiO2.Keywords: anode; core−shell structure; Li-ion batteries; silicon; titanium dioxide;
Co-reporter:Hongsen Li;Xiaoyan Wang;Bing Ding;Gang Pang;Ping Nie;Laifa Shen; Xiaogang Zhang
ChemElectroChem 2014 Volume 1( Issue 7) pp:1118-1125
Publication Date(Web):
DOI:10.1002/celc.201402056
Abstract
Promising energy-storage behavior from molybdenum disulfide (MoS2) in the charging and discharging process is attributed to its layered, two-dimensional structure, which enables convenient electrochemical reactions, but its performance is currently limited by inherent poor electrical conductivity. Herein, we report a facile and efficient method to fabricate a flexible, three-dimensional, binder-free electrode architecture consisting of highly conductive carbon nanotube paper conformally covered by MoS2 nanosheets. Its distinct advantages include abundant porous structure, highly conductive pathway for electrons, and fast transport channels for lithium ions. Electrochemical studies confirm that the MoS2 nanosheets/carbon nanotube paper electrode exhibits outstanding performance in terms of specific capacitance, rate capability, and cycling stability.
Co-reporter:Luojiang Zhang, Jie Wang, Jiajia Zhu, Xiaogang Zhang, Kwan San Hui and Kwun Nam Hui
Journal of Materials Chemistry A 2013 vol. 1(Issue 32) pp:9046-9053
Publication Date(Web):06 Jun 2013
DOI:10.1039/C3TA11755C
A 3D hybrid nickel-aluminum layered double hydroxide (NiAl-LDH)–graphene nanosheets (GNS) composite as a supercapacitor material has been fabricated by in situ deposition of LDH nanosheets on graphene oxide (GO) through a liquid phase deposition method. The results reveal that NiAl-LDH homogeneously grew on the surface of GNS as spacers to keep the neighboring sheets separate. Optimum effects could be achieved when feeding ratio, reaction time and temperature are tuned. The obtained porous GNS/NiAl-LDH composite exhibited high-capacitance performance with a specific capacitance of 1255.8 F g−1 at a current density of 1 A g−1 and 755.6 F g−1 at 6 A g−1, respectively. Moreover, the composite exhibited excellent cycling performance with an increase of 6% capacitance compared with the initial capacitance after 1500 cycle tests. Such high specific capacitance, rate capability and exceptional cycling ability of the composite offered great promise in energy storage device applications.
Co-reporter:Laifa Shen;Evan Uchaker;Guozhong Cao
Advanced Materials 2012 Volume 24( Issue 48) pp:6502-6506
Publication Date(Web):
DOI:10.1002/adma.201203151
Co-reporter:Laifa Shen;Evan Uchaker;Changzhou Yuan;Guozhong Cao
Advanced Energy Materials 2012 Volume 2( Issue 6) pp:
Publication Date(Web):
DOI:10.1002/aenm.201290032
Co-reporter:Laifa Shen;Evan Uchaker;Changzhou Yuan;Guozhong Cao
Advanced Energy Materials 2012 Volume 2( Issue 6) pp:691-698
Publication Date(Web):
DOI:10.1002/aenm.201100720
Abstract
A mesoporous Li4Ti5O12/C nanocomposite is synthesized by a nanocasting technique using the porous carbon material CMK-3 as a hard template. Modified CMK-3 template is impregnated with Li4Ti5O12 precursor, followed by heat treatment at 750 °C for 6 h under N2. Li4Ti5O12 nanocrystals of up to several tens of nanometers are successfully synthesized in micrometer-sized porous carbon foam to form a highly conductive network, as confirmed by field emission scanning electron microscopy, transmission electron microscopy, X-ray diffraction, Raman spectroscopy, and nitrogen sorption isotherms. The composite is then evaluated as an anode material for lithium ion batteries. It exhibits greatly improved electrochemical performance compared with bulk Li4Ti5O12, and shows an excellent rate capability (73.4 mA h g−1 at 80 C) with significantly enhanced cycling performance (only 5.6% capacity loss after 1000 cycles at a high rate of 20 C). The greatly enhanced lithium storage properties of the mesoporous Li4Ti5O12/C nanocomposite may be attributed to the interpenetrating conductive carbon network, ordered mesoporous structure, and the small Li4Ti5O12 nanocrystallites that increase the ionic and electronic conduction throughout the electrode.
Co-reporter:Laifa Shen, Hongsen Li, Evan Uchaker, Xiaogang Zhang, and Guozhong Cao
Nano Letters 2012 Volume 12(Issue 11) pp:5673-5678
Publication Date(Web):October 23, 2012
DOI:10.1021/nl302854j
Because of its extreme safety and outstanding cycle life, Li4Ti5O12 has been regarded as one of the most promising anode materials for next-generation high-power lithium-ion batteries. Nevertheless, Li4Ti5O12 suffers from poor electronic conductivity. Here, we develop a novel strategy for the fabrication of Li4Ti5O12/carbon core–shell electrodes using metal oxyacetyl acetonate as titania and single-source carbon. Importantly, this novel approach is simple and general, with which we have successfully produce nanosized particles of an olivine-type LiMPO4 (M = Fe, Mn, and Co) core with a uniform carbon shell, one of the leading cathode materials for lithium-ion batteries. Metal acetylacetonates first decompose with carbon coating the particles, which is followed by a solid state reaction in the limited reaction area inside the carbon shell to produce the LTO/C (LMPO4/C) core–shell nanostructure. The optimum design of the core–shell nanostructures permits fast kinetics for both transported Li+ ions and electrons, enabling high-power performance.
Co-reporter:Laifa Shen, Evan Uchaker, Changzhou Yuan, Ping Nie, Ming Zhang, Xiaogang Zhang, and Guozhong Cao
ACS Applied Materials & Interfaces 2012 Volume 4(Issue 6) pp:2985
Publication Date(Web):May 25, 2012
DOI:10.1021/am300357b
Mesoporous, micro/nanosized TiO2/C composites with uniformly dispersed TiO2 nanoparticles embedded in a carbon matrix have been rationally designed and synthesized. In brief, TiO2 precursor was infiltrated into the channels of surface-oxidized mesoporous carbon (CMK-3) by means of electrostatic interaction, followed by in situ hydrolysis and growth of TiO2 nanocrystallites, resulting in ultrafine TiO2 nanoparticle confined inside the channels of mesopores carbon. After chemical lithiation and post–annealing, TiO2 nanoparticles were transformed in situ into Li4Ti5O12 to form highly conductivity mesoporous Li4Ti5O12/C composite, as confirmed by scanning electron microscope (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), Raman spectroscopy, and nitrogen sorption isotherms. By combining high electronic conductivity, open mesoporosity, and nanosized active material, coherent mesoporous TiO2/C and Li4Ti5O12/C nanocomposites demonstrated high rate capability and good cycling properties.Keywords: Li4Ti5O12; lithium ion batteries; ordered mesoporous structure; TiO2;
Co-reporter:Luojiang Zhang, Xiaogang Zhang, Laifa Shen, Bo Gao, Liang Hao, Xiangjun Lu, Fang Zhang, Bing Ding, Changzhou Yuan
Journal of Power Sources 2012 Volume 199() pp:395-401
Publication Date(Web):1 February 2012
DOI:10.1016/j.jpowsour.2011.10.056
Graphene nanosheets (GNS)/CoAl-layered double hydroxide (CoAl-LDH) composite with a laminated structure is fabricated by a simple refluxing method. It is found that CoAl-LDH lamellar crystallites gradually self-assemble on the graphene oxide (GO) which is reduced to GNS during the refluxing procedure in the presence of urea. The GNS/CoAl-LDH composite has a higher specific surface area (23.4 m2 g−1) and superior electrochemical performance. As electrode material for supercapacitors, the composite shows a maximum specific capacitance of 711.5 F g−1 at low current density of 1 A g−1, and it remains 516.8 F g−1 when the current density increase to 10 A g−1. Furthermore, the capacitance keeps at least about 81% (compare with 64% for that of pure LDH) after 2000 cycles at 10 A g−1, indicating the composite has excellent high-current capacitive behavior.Graphical abstractCoAl-LDH crystallites grow on graphene sheets by refluxing process and they exhibit excellent high-rate performance and good cycling ability.Highlights► Graphene sheets/CoAl-layered double hydroxide composites were synthesized in one pot. ► The composites show laminated structures without well-defined morphologies. ► The composites show superior electrochemical performance at a high current density. ► The composites could have practical applications for supercapacitors.
Co-reporter:Xiangjun Lu, Hui Dou, Changzhou Yuan, Sudong Yang, Liang Hao, Fang Zhang, Laifa Shen, Luojiang Zhang, Xiaogang Zhang
Journal of Power Sources 2012 Volume 197() pp:319-324
Publication Date(Web):1 January 2012
DOI:10.1016/j.jpowsour.2011.08.112
The flexible electrodes have important potential applications in energy storage of portable electronic devices for their powerful structural properties. In this work, unique flexible films with polypyrrole/carbon nanotube (PPy/CNT) composite homogeneously distributed between graphene (GN) sheets are successfully prepared by flow-assembly of the mixture dispersion of GN and PPy/CNT. In such layered structure, the coaxial PPy/CNT nanocables can not only enlarge the space between GN sheets but also provide pseudo-capacitance to enhance the total capacitance of electrodes. According to the galvanostatic charge/discharge analysis, the mass and volume specific capacitances of GN-PPy/CNT (52 wt% PPy/CNT) are 211 F g−1 and 122 F cm−3 at a current density of 0.2 A g−1, higher than those of the GN film (73 F g−1 and 79 F cm−3) and PPy/CNT (164 F g−1 and 67 F cm−3). Significantly, the GN-PPy/CNT electrode shows excellent cycling stability (5% capacity loss after 5000 cycles) due to the flexible GN layer and the rigid CNT core synergistical releasing the intrinsic differential strain of PPy chains during long-term charge/discharge cycles.Graphical abstractA flexible film with coaxial polypyrrole/carbon nanotube (PPy/CNT) nanocables uniformly distributed between graphene (GN) sheets was prepared by a flow-assembly method, in which flexible GN layer and rigid CNT core could synergistical release the intrinsic differential strain of PPy chains during long-term charge/discharge cycles.Highlights► A hierarchical flexible film composed of GN, PPy and CNT was fabricated. ► The coaxial PPy/CNT nanocables homogeneously insert into the GN sheets. ► The novel film has unique advantages to deliver good electrochemical performance. ► The mass and volume specific capacitances of GN-PPy/CNT reach 211 F g−1 and 122 F cm−3. ► The GN-PPy/CNT shows only 5% capacity loss after 5000 cycles.
Co-reporter:Xiangjun Lu, Fang Zhang, Hui Dou, Changzhou Yuan, Sudong Yang, Liang Hao, Laifa Shen, Luojiang Zhang, Xiaogang Zhang
Electrochimica Acta 2012 Volume 69() pp:160-166
Publication Date(Web):1 May 2012
DOI:10.1016/j.electacta.2012.02.107
In the present work, graphene/polypyrrole/carbon nanotube (GN/PPy/CNT) ternary composites have been fabricated via in situ polymerization method. The negatively charged poly(sodium 4-styrene sulfonate) is used for dispersing GN and CNT in aqueous phase and tethering pyrrole monomer to facilitate the formation of uniform PPy coating. Morphology analysis shows that the stacking of laminated PPy/GN composite is inhibited by introducing one-dimensional CNT to form GN/PPy/CNT composite with three-dimensional hierarchical structure. The prepared GN/PPy/CNT composite with GN:CNT = 8:1 (8GCPPy) exhibits a large surface area of 112 m2 g−1 and meso- and macro-porosity system, which favor the diffusion of the electrolyte ions into the inner region of electrode. The supercapacitive behaviors of the sample electrodes are evaluated with cyclic voltammetry and galvanostatic charge/discharge measurements in 1 M KCl electrolyte. The specific capacitance of 8GCPPy at a current density of 0.2 A g−1 (361 F g−1) is much higher than that of pure PPy (176 F g−1) and binary composites of CNT/PPy (253 F g−1) and GN/PPy (265 F g−1). In addition, owing to the GN and CNT synergistic releasing the intrinsic differential strain of PPy chains during charge/discharge processes, the 8GCPPy composite also shows stable cycling performance (4% capacity loss after 2000 cycles).Graphical abstractTernary nanocomposites composed of graphene (GN), polypyrrole (PPy) and carbon nanotube (CNT) have been prepared via in situ chemical polymerization, where the introduction of one-dimensional CNT can inhibit the stacking of nanosheet-like GN/PPy to form three-dimensional hierarchical architecture.Highlights► Ternary composites composed of GN, PPy and CNT were prepared. ► The introduction of CNT can inhibit the stacking of nanosheet-like GN/PPy. ► The GN/PPy/CNT with GN:CNT = 8:1 (8GCPPy) shows surface area of 112 m2 g−1 and porosity ► The 8GCPPy exhibits the largest the specific capacitance of 361 F g−1 ► The 8GCPPy shows long cycling life stability (4% capacity loss after 2000 cycles).
Co-reporter:Xiangjun Lu, Wei He, Hui Dou, Sudong Yang, Liang Hao, Fang Zhang, Laifa Shen, Xiaogang Zhang
Materials Letters 2012 Volume 71() pp:57-59
Publication Date(Web):15 March 2012
DOI:10.1016/j.matlet.2011.12.037
This study describes a simple and effective ionic liquid (IL)-assisted mechanochemical route to prepare a set of nanostructured graphene nanosheet/polypyrrole (GNS/PPy) composites of with different PPy loading. The functionalized IL 1-butyl-3-methylimidazolium tetrachloroferrate (Bmim[FeCl4]) used here acts as not only the dispersant of GNS but also the catalyst and dopant in the synthesis of PPy. FTIR illustrates the presence of PPy in the composites. A comparative study performed on composites and pure PPy has led to two main conclusions: on one hand, the microstructure of the GNS/PPy composites is dependent on the loading of PPy. On the other hand, GNS/PPy composites show improved conductivity and thermal stability compared with pure PPy.Highlights► GNS/PPy composites with hierarchical architectures are prepared. ► The IL not only the dispersant of GNS but also the catalyst and dopant of PPy. ► The microstructure of the GNS/PPy composites is dependent on the loading of PPy. ► GNS/PPy composites show improved conductivity and thermal stability over pure PPy.
Co-reporter:Xiangjun Lu, Hui Dou, Bo Gao, Changzhou Yuan, Sudong Yang, Liang Hao, Laifa Shen, Xiaogang Zhang
Electrochimica Acta 2011 Volume 56(Issue 14) pp:5115-5121
Publication Date(Web):30 May 2011
DOI:10.1016/j.electacta.2011.03.066
A flexible graphene/multiwalled carbon nanotube (GN/MWCNT) film has been fabricated by flow-directed assembly from a complex dispersion of graphite oxide (GO) and pristine MWCNTs followed by the use of gas-based hydrazine to reduce the GO into GN sheets. The GN/MWCNT (16 wt.% MWCNTs) film characterized by Fourier transformation infrared spectra, X-ray diffraction and scanning electron microscope has a layered structure with MWCNTs uniformly sandwiched between the GN sheets. The MWCNTs in the obtained composite film not only efficiently increase the basal spacing but also bridge the defects for electron transfer between GN sheets, increasing electrolyte/electrode contact area and facilitating transportation of electrolyte ion and electron into the inner region of electrode. Electrochemical data demonstrate that the GN/MWCNT film possesses a specific capacitance of 265 F g−1 at 0.1 A g−1 and a good rate capability (49% capacity retention at 50 A g−1), and displays an excellent specific capacitance retention of 97% after 2000 continuous charge/discharge cycles. The results of electrochemical measurements indicate that the freestanding GN/MWCNT film has a potential application in flexible energy storage devices.Highlights► A flexible graphene/multiwalled carbon nanotube (GN/MWCNT) film fabricated by flow-directed assembly and hydrazine to reduce. ► The MWCNTs in the obtained composite film not only efficiently increase the basal spacing but also bridge the defects for electron transfer between GN sheets. ► The freestanding GN/MWCNT film has a potential application in flexible energy storage devices.
Co-reporter:Xiangjun Lu, Hui Dou, Sudong Yang, Liang Hao, Luojiang Zhang, Laifa Shen, Fang Zhang, Xiaogang Zhang
Electrochimica Acta 2011 Volume 56(Issue 25) pp:9224-9232
Publication Date(Web):30 October 2011
DOI:10.1016/j.electacta.2011.07.142
A film composed of graphene (GN) sheets, polyaniline (PANI) and carbon nanotubes (CNTs) has been fabricated by reducing a graphite oxide (GO)/PANI/CNT precursor prepared by flow-directed assembly from a complex dispersion of GO and PANI/CNT, followed by reoxidation and redoping of the reduced PANI in the composite to restore the conducting PANI structure. Scanning electron microscope images indicate that the ternary composite film is a layered structure with coaxial PANI/CNT nanocables uniformly sandwiched between the GN sheets. Such novel hierarchical structure with high electrical conductivity perfectly facilitates contact between electrolyte ions and PANI for faradaic energy storage and efficiently utilizes the double-layer capacitance at the electrode–electrolyte interfaces. The specific capacitance of the GN/PANI/CNT estimated by galvanostatic charge/discharge measurement is 569 F g−1 (or 188 F cm−3 for volumetric capacitance) at a current density of 0.1 A g−1. In addition, the GN/PANI/CNT exhibits good rate capability (60% capacity retention at 10 A g−1) and superior cycling stability (4% fade after 5000 continuous charge/discharge cycles).Graphical abstractA hierarchical film with coaxial polyaniline/carbon nanotube (PANI/CNT) nanocables uniformly sandwiched between graphene (GN) sheets was prepared by filtration of the complex dispersion of graphite oxide (GO) and PANI/CNT.Highlights► A film composed of GN sheets, PANI and CNTs was fabricated. ► The coaxial PANI/CNT nanocables uniformly sandwiched between the GN sheets. ► The unique structure facilitates contact between electrolyte and electrode materials. ► Each component provides unique function to achieve superior electrochemical properties.
Co-reporter:Laifa Shen, Xiaogang Zhang, Hongsen Li, Changzhou Yuan, and Guozhong Cao
The Journal of Physical Chemistry Letters 2011 Volume 2(Issue 24) pp:3096-3101
Publication Date(Web):November 28, 2011
DOI:10.1021/jz201456p
Nanocrystalline TiO2 grown on conducting graphene nanosheets (GNS) and multiwalled carbon nanotubes (CNTs) via a solution-based method to form a three-dimensional (3D) hierarchical structure for fast lithium storage. CNTs in the unique hybrid nanostructure not only prevent the restacking of GNS to increase the basal spacing between graphene sheets but also provides an additional electron-transport path besides the graphene layer underneath of TiO2 nanomaterials, increasing the electrolyte/electrode contact area and facilitating transportation of the electrolyte ion and electron into the inner region of the electrode. Such a 3D TiO2–GNS–CNT nanocomposite had a large specific surface area of 291.2 m2 g–1 and exhibited ultrahigh rate capability and good cycling properties at high rates.Keywords: anatase titanium dioxide; electron transfer; hybrid nanostructure electrodes; lithium ion batteries; three-dimensional;
Co-reporter:Jian-Shu Huang;Xiao-Gang Zhang;Jian-Min Luo
Journal of Solid State Electrochemistry 2008 Volume 12( Issue 2) pp:113-119
Publication Date(Web):2008 February
DOI:10.1007/s10008-007-0368-3
(Pt–NbPOx)/multi-walled carbon nanotubes (MWCNTs) with different NbPOx MWCNTs were prepared by a simple microwave irradiation method. The (Pt–NbPOx)/MWCNTs catalyst was characterized, and the kinetics toward oxygen reduction reaction (ORR) was determined, compared with that of Pt/MWCNTs catalyst. It was found that 10 wt% NbPOx was the best loading in terms of current density. The number of exchange electrons for the ORR was found to be close to four on both (Pt–NbPOx)/MWCNTs and Pt/MWCNTs.
Co-reporter:Yan-Yu Liang, Hu Lin Li, Xiao-Gang Zhang
Journal of Power Sources 2007 Volume 173(Issue 1) pp:599-605
Publication Date(Web):8 November 2007
DOI:10.1016/j.jpowsour.2007.08.010
A novel solid state route has been successfully developed for the synthesis of nano-scale hydrous ruthenium oxide (denoted as RuO2·xH2O). The procedure involves directly mixing RuCl2·xH2O with alkali to form RuO2·xH2O in a mortar at room temperature. Transmission electron microscopy (TEM) and N2 adsorption–desorption measurement indicate that the RuO2·xH2O particle is approximately 30–40 nm with mesoporous structure. The crystalline structure and the electrochemical properties of RuO2·xH2O have been systematically explored as a function of annealing temperature. At lower temperatures, the RuO2·xH2O powder was found in an amorphous phase and the maximum capacitance of 655 F g−1 was obtained by annealing at 150 °C. Higher temperatures (exceeding 175 °C) presumably converted amorphous phase into crystalline one and the corresponding specific capacitance dropped rapidly from 547 F g−1 at 175 °C to 87 F g−1 at 400 °C. Also, the dependence of electrochemical performance on annealing conditions of RuO2·xH2O was investigated by electrical impedance spectroscopy (EIS) study.
Co-reporter:Quan-Fu Wu, Kuan-Xin He, Hong-Yu Mi, Xiao-Gang Zhang
Materials Chemistry and Physics 2007 Volume 101(2–3) pp:367-371
Publication Date(Web):15 February 2007
DOI:10.1016/j.matchemphys.2006.06.013
Polypyrrole (PPy) nanowires were prepared in high yield by using cetyltrimethylammonium bromide (CTAB) as “soft template” in 0.2 M HCl aqueous solution. From the observation of scanning electron microscopy (SEM) and transmission electron microscopy (TEM), PPy nanowires with a diameter in the range of 30–50 nm was obtained. The electrochemical capacitance of PPy nanowires was characterized by cyclic voltammetry, charge/discharge test and electrochemical impedance spectroscopy (EIS). Compared with conventional PPy, PPy nanowires had the higher specific capacitance and energy density. The capacitor also exhibited the good cycling performance with 1000 cycles.
Co-reporter:Changzhou Yuan, Xiaogang Zhang, Bo Gao, Juan Li
Materials Chemistry and Physics 2007 Volume 101(Issue 1) pp:148-152
Publication Date(Web):15 January 2007
DOI:10.1016/j.matchemphys.2006.03.013
Mesoporous Co(OH)2 was synthesized by using CH3(CH2)10CH2OSO3Na as soft template and urea as hydrolysis-controlling agent. The composition and microstructure of Co(OH)2 was investigated by X-ray diffraction spectroscopy (XRD), scanning electron microscopy (SEM) and nitrogen adsorption and desorption isotherms. Structure characterizations indicated a good mesoporous structure for the prepared Co(OH)2 with adsorption average pore diameter of 11 nm and Brunauer–Emmett–Teller (BET) specific surface area of 283 m2 g−1. Cyclic voltammogram, galvanostatic charge–discharge test, and electrochemical impedance spectroscopy (EIS) analysis showed that the Co(OH)2 possessed good capacitive behavior. The maximum specific capacitance of 341 F g−1 was obtained for the mesoporous Co(OH)2 at a charge/discharge current density of 5 mA cm−2.
Co-reporter:Jie Wang, Ping Nie, Bing Ding, Shengyang Dong, Xiaodong Hao, Hui Dou and Xiaogang Zhang
Journal of Materials Chemistry A 2017 - vol. 5(Issue 6) pp:NaN2428-2428
Publication Date(Web):2016/12/15
DOI:10.1039/C6TA08742F
Electrochemical energy storage devices are becoming increasingly more important for reducing fossil fuel energy consumption in transportation and for the widespread deployment of intermittent renewable energy. The applications of different energy storage devices in specific situations are all primarily reliant on the electrode materials, especially carbon materials. Biomass-derived carbon materials are receiving extensive attention as electrode materials for energy storage devices because of their tunable physical/chemical properties, environmental concern, and economic value. In this review, recent developments in the biomass-derived carbon materials and the properties controlling the mechanism behind their operation are presented and discussed. Moreover, progress on the applications of biomass-derived carbon materials as electrodes for energy storage devices is summarized, including electrochemical capacitors, lithium–sulfur batteries, lithium-ion batteries, and sodium-ion batteries. The effects of the pore structure, surface properties, and graphitic degree on the electrochemical performance are discussed in detail, which will guide further rational design of the biomass-derived carbon materials for energy storage devices.
Co-reporter:Shengyang Dong, Langyuan Wu, Junjun Wang, Ping Nie, Hui Dou and Xiaogang Zhang
Journal of Materials Chemistry A 2017 - vol. 5(Issue 12) pp:NaN5812-5812
Publication Date(Web):2017/02/20
DOI:10.1039/C6TA11040A
There is an urgent need but it is still a huge challenge to integrate high energy and power density with high safety in a single energy storage device. Addressing this issue largely depends on design of new energy storage systems with novel electrode architectures. Herein, a novel electrochemical energy storage device called a quasi-solid-state Na-ion capacitor (QSS-NIC) is designed based on a 3D self-supported Na2Ti3O7 nanoribbon array/graphene foam (NTO/GF) anode and graphene foam (GF) cathode, and a Na-ion conducting gel polymer as the electrolyte and separator, without any binders, conducting additives or metal current collectors. Benefiting from the unique 3D self-supported cathode and anode, the GF//NTO/GF configuration achieves a high energy density of 70.6 W h kg−1 and high power density of 4000 W kg−1 on the basis of the mass of both electrodes, and a prominent cycling stability over 5000 cycles (capacitance retention ∼73.2%). This work successfully demonstrates a proof of concept of QSS-NIC as a high performance energy storage device based on two self-supported electrodes, which could provide a feasible approach to bridge the performance gap between capacitors and Na-ion batteries.
Co-reporter:Laiyang Li, Laifa Shen, Ping Nie, Gang Pang, Jie Wang, Hongsen Li, Shengyang Dong and Xiaogang Zhang
Journal of Materials Chemistry A 2015 - vol. 3(Issue 48) pp:NaN24314-24314
Publication Date(Web):2015/11/02
DOI:10.1039/C5TA07856C
Porous NiCo2O4 nanotubes have been successfully synthesized using a facile and cost-effective electrospinning method and used as a noble-metal-free catalyst for rechargeable Li–O2 batteries. The as-synthesized NiCo2O4 nanotubes possess hollow cavities and porous walls, and were found to significantly improve the electrochemical performance of Li–O2 batteries, by endowing them with a high initial discharge capacity, reduced overpotential as well as good rate capability. Excellent cycling stability over 110 cycles with a highly discharged voltage platform of 2.4 V at 200 mA gc−1 was achieved. By means of FESEM, XRD, Raman spectroscopy and GITT analysis, toroidal-shaped Li2O2 particles were identified as the dominant discharge product and it was revealed that the Li2O2 can be completely decomposed during the charging process, indicating its superior reversibility as an effective bifunctional catalyst for Li–O2 batteries. All the results indicated that the porous NiCo2O4 nanotubes expressed intriguing properties and great potential applications as a noble-metal-free effective bifunctional catalyst for rechargeable Li–O2 batteries.
Co-reporter:Shengyang Dong, Laifa Shen, Hongsen Li, Ping Nie, Yaoyao Zhu, Qi Sheng and Xiaogang Zhang
Journal of Materials Chemistry A 2015 - vol. 3(Issue 42) pp:NaN21283-21283
Publication Date(Web):2015/09/09
DOI:10.1039/C5TA05714K
Hybrid sodium-ion capacitors (NICs) have tremendous potential in large-scale energy storage applications due to their low cost, long lifetime and high power. However, it remains a great challenge to find a desirable anode material with fast kinetics and superior cycle life. Here an applicable strategy to in situ grow Na2Ti3O7 on 1D CNTs as an anode material for sodium-ion capacitors is presented. Benefiting from the unique 1D nanostructure and the presence of pseudocapacitive charge storage mechanism, the Na2Ti3O7@CNT electrode exhibits excellent electrochemical performance with high rate capability and superb cycling stability. Moreover, a high performance hybrid NIC is also fabricated by using Na2Ti3O7@CNTs as an anode and activated carbon derived from the outer peanut shell as a cathode, which delivers high energy density (58.5 W h kg−1), high power density (3000 W kg−1), and long term cycle life (retaining ca. 75% of its original capacity at 0.4 A g−1 after 4000 cycles).
Co-reporter:Hao Zheng, Shan Fang, Zhenkun Tong, Gang Pang, Laifa Shen, Hongsen Li, Liang Yang and Xiaogang Zhang
Journal of Materials Chemistry A 2015 - vol. 3(Issue 23) pp:NaN12481-12481
Publication Date(Web):2015/05/06
DOI:10.1039/C5TA02259B
In this work, TiN NW supported silicon nanorods (TiN@Si NRs) are produced via direct radio frequency (RF) magnetron sputtering of Si deposition onto the surface of TiN NWs. Due to its superior mechanical stability and electrical conductivity, TiN provides more stable support and better conductive pathways for Si when compared with TiO2. The unique core–shell TiN@Si NR structure has enough void space to accommodate the large volume changes of Si during charge/discharge cycling. The novel 3D architecture electrode demonstrates exceptional electrochemical performances with ultrahigh specific capacity. Comparing with TiO2@Si NRs, TiN@Si NR electrodes exhibit improved cycling performances, which can still retain a capacity of 3258.8 mA h g−1 after 200 cycles at 1 A g−1. It should be noted that the TiN@Si NRs show an excellent rate performance even at a high current density (2256.6 mA h g−1 is realized at 10 A g−1). These results endow the electrodes with high power and long cycling stability.
Co-reporter:Hao Tong, Wenlong Bai, Shihong Yue, Zhenzhen Gao, Liang Lu, Laifa Shen, Shengyang Dong, Jiajia Zhu, Jianping He and Xiaogang Zhang
Journal of Materials Chemistry A 2016 - vol. 4(Issue 29) pp:NaN11263-11263
Publication Date(Web):2016/06/08
DOI:10.1039/C6TA02249A
To improve the energy density of supercapacitors, a new type of electrode material with high electrochemical activity and favorable morphology is extremely desired. Ternary metal sulfides with higher electrochemical capacity and activity than mono-metal sulfides hold great promise in the field of energy storage devices. Herein, an advanced electrode composed of zinc cobalt sulfide nanosheets supported on sandwich-like nitrogen-doped graphene/carbon nanotubes (NGN/CNTs) film has been successfully fabricated through a two-step synthesis. Benefiting from the characteristic features and 3D electrode architectures, the Zn0.76Co0.24S electrode exhibits a high specific capacitance of 2484 F g−1 at 2 A g−1 and excellent cycling stability (almost no capacitance fading after 10000 cycles at 30 A g−1). This creative nanostructure design of ternary transition metal sulfides could provide a promising prospect for application in energy storage devices. Moreover, an asymmetric supercapacitor was also fabricated by using Zn0.76Co0.24S/NGN/CNTs film as the positive electrode and NGN/CNTs film as the negative electrode, exhibiting a high energy density of 50.2 W h kg−1 at 387.5 W kg−1 and superior cycling stability of 100% initial capacity retention over 2000 cycles. This creative nanostructure design could provide a promising new way to develop high-performance supercapacitors and shed new light on configuring carbon-based ternary transition metal sulfide electrode materials in energy storage and conversion devices.
Co-reporter:Shan Fang, Laifa Shen, Hao Zheng and Xiaogang Zhang
Journal of Materials Chemistry A 2015 - vol. 3(Issue 4) pp:NaN1503-1503
Publication Date(Web):2014/11/14
DOI:10.1039/C4TA04350B
A Ge–graphene–carbon nanotube composite electrode was constructed by germanium (Ge) nanoparticles anchored on reduced graphene oxide (Ge–RGO) intertwined with carbon nanotubes (CNT). In this unique structure, the graphene sheets improve the electrical conductivity and buffer severe volume changes. Additionally, the CNT mechanically binds together with Ge–RGO to maintain the integrity of the electrodes and stabilize the electric conductive network for the active Ge nanoparticles, leading to better cycling performance. As a result, the designed anode exhibits an outstanding energy capacity up to 863.8 mA h g−1 at a current density of 100 mA g−1 after 100 cycles and good rate performances of 1181.7, 1073.8, 1005.2, 872.0, 767.6, and 644.8 mA h g−1 at current densities of 100, 200, 400, 800, 1600, and 3200 mA g−1, respectively. Our results indicate that the hybrids exhibit considerably improved lithium storage performance.
Co-reporter:Jie Wang, Laifa Shen, Ping Nie, Xiaoliang Yun, Yunling Xu, Hui Dou and Xiaogang Zhang
Journal of Materials Chemistry A 2015 - vol. 3(Issue 6) pp:NaN2860-2860
Publication Date(Web):2014/12/12
DOI:10.1039/C4TA05932H
Improving the electrochemical performance of supercapacitors mainly depends on the electrode design and system construction. A new kind of additive-free asymmetric supercapacitors (ASCs) has been successfully fabricated using a self-supported carbon foam/ordered mesoporous carbon (CF-OMC) film as the negative electrode and free-standing CF-NiCo2O4 nanosheets (NSs) as the positive electrode, respectively. The highly conductive three-dimensional (3D) CF framework could facilitate electron transfer while the porous thin film of OMC and ultrathin NiCo2O4 nanosheets could shorten the ion diffusion path and facilitate the rapid migration of electrolyte ions. The optimized asymmetric supercapacitors could work with an operational voltage of 1.6 V, delivering a high energy density (∼47.8 W h kg−1), high power density (∼9800 W kg−1 at 17.7 W h kg−1) and outstanding cycle stability (∼10000 times). This research may pave the way for fabricating lightweight, low-cost, and high-performance electrodes for energy storage applications.
Co-reporter:Ping Nie, Laifa Shen, Gang Pang, Yaoyao Zhu, Guiyin Xu, Yunhua Qing, Hui Dou and Xiaogang Zhang
Journal of Materials Chemistry A 2015 - vol. 3(Issue 32) pp:NaN16597-16597
Publication Date(Web):2015/07/10
DOI:10.1039/C5TA03197D
In response to the ever-increasing demand for grid-scale energy storage systems, sodium ion batteries (SIBs) working at ambient- or room-temperature are gaining much attention as promising alternatives because of the abundance and low cost of sodium resources. However, their adoption is significantly hampered by several issues, especially in terms of sluggish kinetics and capacity retention during cycling. Herein, flexible Prussian blue analogue FeFe(CN)6/carbon cloth composites are synthesized using low temperature strategies and utilized as a potential host for sodium ion insertion. As a proof of concept, the composites demonstrate excellent electrochemical performance: a reversible specific capacity of 82 mA h g−1 at 0.2C, good rate capability and long term cycling life with 81.2% capacity retention over 1000 cycles. Most significantly, this low-cost, scalable and low-temperature synthesis provides guidance for the design of other flexible materials that could have applications in wearable electronics, energy storage and conversion devices.
Co-reporter:Hongsen Li, Laifa Shen, Jie Wang, Shan Fang, Yingxia Zhang, Hui Dou and Xiaogang Zhang
Journal of Materials Chemistry A 2015 - vol. 3(Issue 32) pp:NaN16790-16790
Publication Date(Web):2015/07/10
DOI:10.1039/C5TA02929E
Hybrid supercapacitors are a very appealing power source with high energy density and power density because they employ both the merits of lithium ion batteries and supercapacitors. To balance such hybrid systems, the rate of the redox component must be substantially comparative to the levels of the double layer process. As far as the insertion-host material TiNb2O7 is concerned, we have used facile step electrode design consisting of the physically assisted template infusion of Ti–Nb sol into the pores of AAO followed by in situ conversion into porous TiNb2O7 nanotubes within the AAO walls under calcination, and finally making those templates dissolve away. Using such an electrode as the battery type anode and a graphene grass electrode as the capacitor type cathode, we successfully constructed a novel hybrid supercapacitor. Within a voltage range of 0–3 V, a high energy density of ∼74 W h kg−1 is achieved and it could remain as much as ∼34.5 W h kg−1 at a power of 7500 W kg−1. The present research sheds new light on the development of energy storage devices with both high energy density and high power density.
Co-reporter:Wenlong Bai, Hao Tong, Zhenzhen Gao, Shihong Yue, Sichuan Xing, Shengyang Dong, Laifa Shen, Jianping He, Xiaogang Zhang and Yanyu Liang
Journal of Materials Chemistry A 2015 - vol. 3(Issue 43) pp:NaN21898-21898
Publication Date(Web):2015/09/10
DOI:10.1039/C5TA05798A
Homogeneous ZnCo2O4 nanoflowers have been synthesized on a 3D layered structure of carbon nanotubes/nitrogen-doped graphene (NGN/CNTs) film by a hydrothermal process and subsequent calcination method. The ZnCo2O4 nanoflowers have an average diameter of 4 μm, and are composed of petals less than 100 nanometers. The as-synthesized ZnCo2O4/NGN/CNT film can be directly used as a flexible electrode with a high specific capacitance of 1802 F g−1 at 1 A g−1 and excellent cycling stability (almost 0% fade after 4000 sustaining charge/discharge at 10 A g−1). These results suggest that the obtained electrode has a promising application prospect in flexible energy conversion/storage devices. In addition, a binder-free asymmetric supercapacitor has been synthesized with the ZnCo2O4/NGN/CNT film as the positive electrode and the NGN/CNT film as the negative electrode. This demonstrates superior energy density (≈37.19 W h kg−1 at 750 W kg−1) and power density (≈14.992 kW kg−1 at 14.16 W h kg−1).
Co-reporter:Luojiang Zhang, Jie Wang, Jiajia Zhu, Xiaogang Zhang, Kwan San Hui and Kwun Nam Hui
Journal of Materials Chemistry A 2013 - vol. 1(Issue 32) pp:NaN9053-9053
Publication Date(Web):2013/06/06
DOI:10.1039/C3TA11755C
A 3D hybrid nickel-aluminum layered double hydroxide (NiAl-LDH)–graphene nanosheets (GNS) composite as a supercapacitor material has been fabricated by in situ deposition of LDH nanosheets on graphene oxide (GO) through a liquid phase deposition method. The results reveal that NiAl-LDH homogeneously grew on the surface of GNS as spacers to keep the neighboring sheets separate. Optimum effects could be achieved when feeding ratio, reaction time and temperature are tuned. The obtained porous GNS/NiAl-LDH composite exhibited high-capacitance performance with a specific capacitance of 1255.8 F g−1 at a current density of 1 A g−1 and 755.6 F g−1 at 6 A g−1, respectively. Moreover, the composite exhibited excellent cycling performance with an increase of 6% capacitance compared with the initial capacitance after 1500 cycle tests. Such high specific capacitance, rate capability and exceptional cycling ability of the composite offered great promise in energy storage device applications.
![tricobalt bis[hexa(cyano-C)cobaltate(3-)]](http://img.cochemist.com/ccimg/14200/14123-08-1.png)
![tricobalt bis[hexa(cyano-C)cobaltate(3-)]](http://img.cochemist.com/ccimg/14200/14123-08-1_b.png)
