An investigation of V₂O₅/polypyrrole composite cathode materials for lithium-ion batteries synthesized by sol-gel

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• 作者：Xiangzhong Ren ; Chuan Shi ; Peixin Zhang ; ^{pxzhang@szu.edu.cn} ; Yingkai Jiang ; Jianhong Liu ; Qianling Zhang
• 关键词：Vanadium pentoxide ; Polypyrrole ; Cathode material ; Sol&ndash ; gel method
• 刊名：Materials Science and Engineering ; B
• 出版年：2012
• 期刊代码：76_09215107
• 类别：ch
• 出版时间：25 July, 2012
• 卷：177
• 期：12
• 页码：929-934
• 文件大小：903 K

摘要

A lamellar compound of V₂O₅ was prepared by a simple sol-gel method using H₂O₂ and V₂O₅ as starting materials. The composites of V₂O₅/PPy (polypyrrole) were synthesized by in situ polymerization, and characterized by thermogravimetric analysis (TGA), scanning electron microscopy (SEM), Fourier transform infrared (FTIR) spectrum, and X-ray diffraction (XRD). The electrochemical properties of the composites were investigated with galvanostatic charge-discharge test, cyclic voltammetry and A.C. impedance techniques. The results show that pyrrole was uniformly polymerized around the V₂O₅, and the V₂O₅/PPy composite possessed excellent electrochemical performance. The specific discharge capacity of the 2.5%mass percent PPy composites (271.8 mAh g^鈭?) was higher than that of pure V₂O₅ (247.6 mAh g^鈭?) at 0.1C rate and it has the voltage limits of 1.8-4.0 V. Furthermore, the specific discharge capacity remained at 225.4 mAh g^鈭? after 50 cycles. The chemical diffusion coefficient values were calculated, depending on x-values in Li_x+1.1V₂O₅. The values of range from 2.18 脳 10^鈭?2 cm² s^鈭? to 4.5 脳 10^鈭?4 cm² s^鈭? for V₂O₅/PPy composite, and it decreased as the amount of intercalated Li⁺ increased.