Electrochemical Performance and Capacity Fading Mechanism of LiFePO4 at Different pH Aqueous Electrolyte Solutions
Electrochemical Performance and Capacity Fading Mechanism of LiFePO4 at Different pH Aqueous Electrolyte Solutions作者机构：College of Materials Science and Engineering Beijing University of Chemical Technology Beijing 100029 China Research Institute of Chemical Defence Beijing 100191 China
出 版 物：《Chinese Journal of Chemical Physics》 (化学物理学报（英文）)
年 卷 期：2015年第28卷第3期
页 面：315-322,I0002页
核心收录：
学科分类：0808[工学-电气工程] 081704[工学-应用化学] 08[工学] 0817[工学-化学工程与技术] 0703[理学-化学] 0702[理学-物理学]
基 金：supported by the Research Institute of Chemical Defence
主 题：Olivine LiFePOa Aqueous electrolyte Electrochemical property Capacityfade Mechanism
摘 要：The electrochemical stability of LiFePO4 in a Li＋-containing aqueous electrolyte solution is critically dependent on the pH value of the aqueous solution. It shows a considerable decay in capacity of LiFePO4 upon cycling when the pH value is increased to 11. The mechanism responsible for the capacity fading is extensively investigated by means of cyclic voltammogram, ac impedance, charge/discharge, ex situ X-ray diffraction, and chemical analysis. LiFePO4 is relatively electrochemically stable in LiNO3 aqueous solution with pH=7. But the electrochemical performance of LiFePO4 in aqueous electrolyte is inferior to that in organic electrolyte. It is attributed to the loss of Li and the Fe, P dissolution during prolonged charge-discharge in aqueous medium. A precipitate is formed on the surface of LiFePO4 electrodes. It results in the change of crystalline structure, a large electrode polarization, and capacity fading.
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