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Full-Text Articles in Physical Sciences and Mathematics

Flexible Free-Standing Graphene-Silicon Composite Film For Lithium-Ion Batteries, Jiazhao Wang, Chao Zhong, Shulei Chou, Hua Liu Feb 2013

Flexible Free-Standing Graphene-Silicon Composite Film For Lithium-Ion Batteries, Jiazhao Wang, Chao Zhong, Shulei Chou, Hua Liu

Shulei Chou

Flexible, free-standing, paper-like, graphene-silicon composite materials have been synthesized by a simple, one-step, in-situ filtration method. The Si nanoparticles are highly encapsulated in a graphene nanosheet matrix. The electrochemical results show that graphene-Si composite film has much higher discharge capacity beyond 100 cycles (708 mAh g− 1) than that of the cell with pure graphene (304 mAh g− 1). The graphene functions as a flexible mechanical support for strain release, offering an efficient electrically conducting channel, while the nanosized silicon provides the high capacity.


Nanocrystalline Nio Hollow Spheres In Conjunction With Cmc For Lithium-Ion Batteries, Chao Zhong, Jiazhao Wang, Shulei Chou, Konstantin Konstantinov, Mokhlesur Rahman, Hua Liu Feb 2013

Nanocrystalline Nio Hollow Spheres In Conjunction With Cmc For Lithium-Ion Batteries, Chao Zhong, Jiazhao Wang, Shulei Chou, Konstantin Konstantinov, Mokhlesur Rahman, Hua Liu

Shulei Chou

Hollow spherical NiO particles were prepared using the spray pyrolysis method with different concentrations of precursor. The electrochemical properties of the NiO electrodes, which contained a new type of binder, carboxymethyl cellulose (CMC), were examined for comparison with NiO electrodes with polyvinylidene fluoride (PVDF) binder. The electrochemical performance of NiO electrodes using CMC binder was significantly improved. For the cell made from 0.3 mol L−1 precursor, the irreversible capacity loss between the first discharge and charge is about 43 and 24% for the electrode with PVDF and CMC binder, respectively. The cell with NiO–CMC electrode has a much higher discharge …


Paper-Like Free-Standing Polypyrrole And Polypyrrole-Lifepo4 Composite Films For Flexible And Bendable Rechargeable Battery, Jun Chen, Sau Yen Chew, S. Dou, Jiazhao Wang, Guoxiu Wang, Hua Liu, Konstantin Konstantinov, Jian Wu, Shulei Chou Nov 2012

Paper-Like Free-Standing Polypyrrole And Polypyrrole-Lifepo4 Composite Films For Flexible And Bendable Rechargeable Battery, Jun Chen, Sau Yen Chew, S. Dou, Jiazhao Wang, Guoxiu Wang, Hua Liu, Konstantin Konstantinov, Jian Wu, Shulei Chou

Shulei Chou

Highly flexible, paper-like, free-standing polypyrrole and polypyrrole-LiFePO4 composite films were prepared using the electropolymerization method. The films are soft, lightweight, mechanically robust and highly electrically conductivity. The electrochemical performance of the free-standing pure PPy electrode was improved by incorporating the most promising cathode material, LiFePO4, into the PPy films. The cell with PPy-LiFePO4 composite film had a higher discharge capacity beyond 50 cycles (80 mA h/g) than that of the cell with pure PPy (60 mA h/g). The free-standing films can be used as electrode materials to satisfy the new market demand for flexible and bendable batteries that are suitable …


Electrochemical Deposition Of Porous Vox And Mno2 Nanowires On Stainless Steel Mesh For Flexible Supercapacitors, Shulei Chou, Jiazhao Wang, Hua Liu, S Dou Nov 2012

Electrochemical Deposition Of Porous Vox And Mno2 Nanowires On Stainless Steel Mesh For Flexible Supercapacitors, Shulei Chou, Jiazhao Wang, Hua Liu, S Dou

Shulei Chou

Porous vanadium oxide (VOx) and MnO2 nanowires were synthesized by an electrochemical deposition method using stainless steel mesh as substrate. The as-prepared porous VOx and MnO2 nanowire films were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and Raman spectroscopy. The cyclic voltammetry (CV) results show that the MnO2 nanowire film shows specific capacitance of 195, 170, 158, and 91 F g-1 at scan rates of 5, 10, 20, and 50 mV s-1, respectively. The porous VOx film displays specific capacitance of 152, 124, 99, and 76 F g …


Sulfur-Mesoporous Carbon Composites In Conjunction With A Novel Ionic Liquid Electrolyte For Lithium Rechargeable Batteries, Jun Chen, Syed Ashraf, Sau Yen Chew, See How Ng, David Wexler, Jiazhao Wang, Hua Liu, Zhengwei Zhao, Shulei Chou Nov 2012

Sulfur-Mesoporous Carbon Composites In Conjunction With A Novel Ionic Liquid Electrolyte For Lithium Rechargeable Batteries, Jun Chen, Syed Ashraf, Sau Yen Chew, See How Ng, David Wexler, Jiazhao Wang, Hua Liu, Zhengwei Zhao, Shulei Chou

Shulei Chou

Sulfur coated mesoporous carbon (S-C) composites have been synthesized and physically characterized by scanning electron microscopy, transmission electron microscopy, Raman spectroscopy, and thermogravimetric analysis. Firstly, the electrochemical properties of the S-C composite cathode materials were tested in a conventional electrolyte consisting of 1 mol/L lithium bistrifluormethanesulfonimidate in poly(ethylene glycol) dimethyl ether to compare them with pure sulphur electrode. The capacity and cyclic stability of the S-C composite were improved. Then the S-C composites were tested in a novel ionic liquid electrolyte consisting of 1-ethyl-3-methylimidazolium bis(trifluromethanesulfonyl)imide and lithium


Flexible Free-Standing Carbon Nanotube Films For Model Lithium-Ion Batteries, Jun Chen, Sau Yen Chew, See How Ng, Jiazhao Wang, Hua Liu, P Novak, F Krumeich, Shulei Chou Nov 2012

Flexible Free-Standing Carbon Nanotube Films For Model Lithium-Ion Batteries, Jun Chen, Sau Yen Chew, See How Ng, Jiazhao Wang, Hua Liu, P Novak, F Krumeich, Shulei Chou

Shulei Chou

No abstract provided.