Synthesis and electrochemical properties of Li₃V₂(PO₄)₃/C cathode material with an improved sol-gel method by changing pH value

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• 作者：Wenwen Xu ; Li Liu ; Haolong Guo ; Ruisong Guo ; Chao Wang
• 关键词：Lithium ion battery ; Cathode material ; Li3V2(PO4)3 ; pH value ; Electrochemical performance
• 刊名：Electrochimica Acta
• 出版年：15 December, 2013
• 年：2013
• 卷：113
• 期：Complete
• 页码：497-504
• 全文大小：3187 K

文摘

An improved sol-gel method by changing pH value is developed to synthesize high performance Li₃V₂(PO₄)₃/C cathode material. Li₃V₂(PO₄)₃/C powders are prepared by a conventional sol-gel process without special controlling pH value and the improved sol-gel process, respectively. They are characterized by X-ray diffractometer (XRD), scanning electron microscopy (SEM), high resolution transmission electron microscopy (HRTEM), galvanostatic charge/discharge test, cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) and potential step chronoamperometry (PSCA). Not only the cycle performance for the samples prepared by the improved sol-gel method shows obvious enhancement compared with that for the sample prepared via a conventional sol-gel process, but also initial specific capacities have been improved markedly. In the voltage range of 3.0-4.8 V, the sample prepared at pH value of 4 exhibits an optimum capability at low-rate. The sample prepared at pH value of 9 possesses a good performance at high-rate. The enhanced electrochemical performance can be attributed to the microstructure of the powders, which can make the lithium ion diffusion and electron transfer easier across the Li₃V₂(PO₄)₃/C interfaces, thus resulting in enhanced electrode reaction kinetics and improved electrochemical performance.