锂离子二次电池容量损失的电化学修复

来源期刊:中南大学学报(自然科学版)2010年第4期

论文作者:罗卓 唐新村 李连兴 陈静波

文章页码:1276 - 1280

关键词:锂离子二次电池;电化学修复;化学式

Key words:lithium secondary batteries; electrochemical recovery; chemical formula

摘    要:以比亚迪公司生产的额定容量为950 mA·h的LP063450AR型方型锂离子电池为样品电池,对锂离子二次电池容量损失的电化学修复进行研究,并采用X线衍射(XRD)、电化学交流阻抗(EIS)以及电感耦合等离子体发射光谱(ICP-AES)等手段探讨修复机理。结果表明:通过插入适当小电流充放电循环, 可对二次电池多次循环后所导致的容量损失进行有效修复。在充、放电倍率为1C和2C时,每50次循环后通过修复,电池容量较修复前平均增加40~50 mA·h;300次循环结束后,电池容量仍保持在860 mA·h和750 mA·h左右;300次循环后,放电态时修复前、后电池正极材料化学式分别为Li0.776CoO2和Li0.907CoO2,经过修复,更多的Li+在正极嵌入,活性材料的使用得到提高。

Abstract: Based on the performance of the commercial quadrate Li-ion batteries (LP063450AR, 950 mA·h) provided by BYD Battery Ltd. (Shenzhen, China), the feasibility of electrochemical recovery of capacity loss for lithium secondary batteries was studied. The mechanism of electrochemical recovery was characteried by X-ray diffraction, electrochemical impendance spectrum and indictive coupled plasma-atomic emission spectroscopy. The results show that the capacity loss of lithium secondary batteries with cycling can be effectively prohibited by adding the proper low current charge/discharge process. After every 50 cycles, the discharge capacity increases by 40-50 mA·h after recovery for the batteries cycled at 1C and 2C rate. The chemical formula of the positive material is Li0.776CoO2 and Li0.907CoO2 respectively before/after recovery after 300 cycles. The recovery mechanism can be attributed to more Li-ion intercalating into the LiCoO2 lattice and thus enhancing the usage of active material of batteries.

基金信息:国家自然科学基金资助项目

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