Journal of Inorganic Materials ›› 2021, Vol. 36 ›› Issue (2): 175-180.DOI: 10.15541/jim20200012

Special Issue: 能源材料论文精选(2021)

• RESEARCH PAPER • Previous Articles     Next Articles

Storage Aging Mechanism of LiNi0.8Co0.15Al0.05O2/Graphite Li-ion Batteries at High State of Charge

LIU Yong1, BAI Haijun1, ZHAO Qizhi1, YANG Jinge1, LI Yujie2(), ZHENG Chunman2(), XIE Kai2   

  1. 1. 61699 Unit of People’s Liberation Army of China, Zhijiang 443200, China
    2. College of Aerospace Science and Engineering, National University of Defense Technology, Changsha 410073, China
  • Received:2020-01-08 Revised:2020-03-27 Published:2021-02-20 Online:2020-04-05
  • About author:LIU Yong(1989-), male, PhD, engineer. E-mail: liuzi244@sina.com
  • Supported by:
    Equipment Pre Research Fund(JZX5Y20190261003101)

Abstract:

Storage life at high state of charge is a key factor affecting the application of Li ion battery, but the related mechanism research is insufficient. In this study, the storage life of LiNi0.8Co0.15Al0.05O2 (NCA)/graphite battery was evaluated via accelerating experiment at elevated temperature, and the electrochemistry performances and interface properties of fresh and aged active materials were analyzed. Storage experiment shows that the storage life of NCA/graphite battery at high state of charge under 55 ℃ is about 90 d. Electrochemical test shows that the capacities of NCA and graphite decrease when the batteries reach the end of life, but that is not the main cause inducing capacity degradation. Interface analysis illustrates that the solid electrolyte interface (SEI) film on graphite anode significantly grows when batteries reach the end of life, while the positive solid electrolyte interface (PEI) film on NCA cathode keeps basically unchanged. The growth of SEI film on graphite owing to the decomposition of carbonates in electrolyte results in Li loss in anode, which contributes to the capacity loss of NCA/graphite battery during the storage aging at high state of charge.

Key words: Li ion battery, NCA/graphite, storage aging, capacity fading, solid electrolyte interface (SEI)

CLC Number: