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Heterogeneous Degradation in Thick Nickel‐Rich Cathodes During High‐Temperature Storage and Mitigation of Thermal Instability by Regulating Cationic Disordering
Author(s) -
Zhang Lihan,
Zhao Chenglong,
Qin Xianying,
Wang Shuwei,
He Lunhua,
Qian Kun,
Han Ting,
Yang Zhangping,
Kang Feiyu,
Li Baohua
Publication year - 2021
Publication title -
small
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.785
H-Index - 236
eISSN - 1613-6829
pISSN - 1613-6810
DOI - 10.1002/smll.202102055
Subject(s) - materials science , cathode , degradation (telecommunications) , nickel , instability , cationic polymerization , thermal stability , thermal , thermal treatment , electrode , chemical engineering , intergranular corrosion , composite material , microstructure , metallurgy , chemistry , telecommunications , physics , meteorology , computer science , mechanics , polymer chemistry , engineering
The thermal instability is a major problem in high‐energy nickel‐rich layered cathode materials for large‐scale battery application. Due to the scarce investigation of thick electrodes at the practical full‐cell level, the understanding of thermal failure mechanism is still insufficient. Herein, an intrinsic origin of thermal instability in fully charged industrial pouch cells during high‐temperature storage is discovered. Through the investigation from crystals to particles, and from electrodes to cells, it is shown that serious top‐down heterogeneous degradation occurs along the depth direction of the thick electrode, including phase transition, cationic disordering, intergranular/intragranular cracks, and side reactions. Such degradation originates from the abundant oxygen vacancies and reduced catalytic Ni 2+ at cathode surface, causing microstructural defects and directly leading to the thermal instability. Nonmagnetic elements doping and surface modification are suggested to be effective in mitigating the thermal instability through modulating cationic disordering.