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电化学(中英文) ›› 2012, Vol. 18 ›› Issue (2): 118-124.  doi: 10.61558/2993-074X.2890

• 化学电源近期研究专辑(武汉大学 杨汉西教授主编) • 上一篇    下一篇

锂离子电池正极材料LiNi0.5Co0.2Mn0.3O2的合成及其高温容量衰减研究

刘文, 王苗, 陈继涛*, 张新祥, 周恒辉*   

  1. 先进电池材料理论与技术北京市重点实验室,化学与分子工程学院,北京大学,北京100871
  • 收稿日期:2011-11-24 修回日期:2011-12-27 出版日期:2012-04-28 发布日期:2012-01-15
  • 通讯作者: 陈继涛, 周恒辉 E-mail: chenjitao@pku.edu.cn, hhzhou@pku.edu.cn
  • 基金资助:

    国家高技术研究发展计划(No. 2009AA035200)资助

Synthesis of LiNi0.5Co0.2Mn0.3O2 for lithium Ion Batteries and the Mechanism of Capacity Fading at High Temperature

LIU  Wen, WANG  Miao, CHEN  Ji-Tao*, ZHANG  Xin-Xiang, ZHOU  Heng-Hui*   

  1. Beijing Key Laboratory in Theory and Technology of Advanced Materials for Batteries, College of Chemistry and Molecular Engineering, Peking University, Beijing, China, 100871
  • Received:2011-11-24 Revised:2011-12-27 Published:2012-04-28 Online:2012-01-15
  • Contact: CHEN Ji-Tao, ZHOU Heng-Hui E-mail: chenjitao@pku.edu.cn, hhzhou@pku.edu.cn

摘要: 采用共沉淀-高温固相烧结法合成了富镍型三元复合正极材料LiNi0.5Co0.2Mn0.3O2,恒流充放电测试表明材料在3.0 ~ 4.4 V条件下0.2C放电容量达到179.2 mAh?g-1,但在55 °C经历100次充放电循环后发生急剧的容量衰减。电化学交流阻抗谱、X射线光电子能谱、原子发射光谱等实验表明在高温高电压下,电解液与LiNi0.5Co0.2Mn0.3O2电极材料之间的副反应加剧,导致过渡金属原子溶出,造成该材料局域结构破坏,同时电极材料表面还沉积了高阻抗的LiF/金属氟化物层,使得在电极的充放电过程中电荷转移阻抗和Li+扩散阻抗不断增加,以致电池容量急剧衰减。

关键词: 锂离子电池正极材料, LiNi0.5Co0.2Mn0.3O2, 高温容量衰减, X射线光电子能谱, 交流阻抗谱

Abstract: The Ni-rich cathode materials, LiNi0.5Co0.2Mn0.3O2, have been synthesized by Co-precipitation and high-temperature solid-phase sintering method. Constant current charge-discharge tests showed high discharge capacity of 179.2 mAh.g-1 in the 3.0 ? 4.4 V at 0.2C. However, at 55 °C the LiNi0.5Co0.2Mn0.3O2 experienced the dramatic capacity fading after 100 charge-discharge cycles. Electrochemical Impedance Spectroscopy, X-Ray Photoelectron Spectroscopy, Atomic Emission Spectroscopy have been employed to study the capacity fading mechanism of LiNi0.5Co0.2Mn0.3O2 cycled at high temperature in range of high-voltage charge and discharge conditions. It was found that at high temperature under conditions of high-voltage range, the side reactions between the electrolyte and electrode would be accelerated, leading to dissolution of transition metal atoms and resulting in the local structure damage of cathode material. Meanwhile, the byproducts could be deposited on the electrode surface as a high impedance LiF/metal fluoride layer, the charge-transfer resistance and Li+ diffusion resistance were increased, resulting in a sharp capacity degradation.

Key words: Lithium-ion batteries, LiNi0.5Co0.2Mn0.3O2, capacity fading, X-ray photoelectron spectroscopy, AC impedance spectroscopy;

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