Long‐Range Cationic Disordering Induces two Distinct Degradation Pathways in Co‐Free Ni‐Rich Layered Cathodes

• Published in: Angewandte Chemie International Edition Vol. 62; no. 12; pp. e202214880 - n/a
• Main Authors: Hua, Weibo, Zhang, Jilu, Wang, Suning, Cheng, Yi, Li, Hang, Tseng, Jochi, Wu, Zhonghua, Shen, Chong‐Heng, Dolotko, Oleksandr, Liu, Hao, Hung, Sung‐Fu, Tang, Wei, Li, Mingtao, Knapp, Michael, Ehrenberg, Helmut, Indris, Sylvio, Guo, Xiaodong
• Format: Journal Article
• Language: English
• Published: Germany Wiley Subscription Services, Inc 13.03.2023
• Edition: International ed. in English
• Subjects: Batteries; Cathodes; Cationic Disordering; Cations; Core-shell structure; Cycles; Decay; Decay rate; Degradation; Degradation Pathways; Electrochemistry; Electrode materials; Lattice Distortion; Lithium; Lithium-ion batteries; Ni-Rich Cathodes; Surface Reconstruction; Cationic Disordering; Lattice Distortion; Surface Reconstruction; Degradation Pathways; Ni-Rich Cathodes
• ISSN: 1433-7851; 1521-3773
• DOI: 10.1002/anie.202214880

Ni‐rich layered oxides are one of the most attractive cathode materials in high‐energy‐density lithium‐ion batteries, their degradation mechanisms are still not completely elucidated. Herein, we report a strong dependence of degradation pathways on the long‐range cationic disordering of Co‐free Ni‐rich Li1−m(Ni0.94Al0.06)1+mO2 (NA). Interestingly, a disordered layered phase with lattice mismatch can be easily formed in the near‐surface region of NA particles with very low cation disorder (NA‐LCD, m≤0.06) over electrochemical cycling, while the layered structure is basically maintained in the core of particles forming a “core–shell” structure. Such surface reconstruction triggers a rapid capacity decay during the first 100 cycles between 2.7 and 4.3 V at 1 C or 3 C. On the contrary, the local lattice distortions are gradually accumulated throughout the whole NA particles with higher degrees of cation disorder (NA‐HCD, 0.06≤m≤0.15) that lead to a slow capacity decay upon cycling. A series of Ni‐rich Li1−m(Ni0.94Al0.06)1+mO2 (NA) oxides are synthesized through tailoring the heating temperature. The NA oxides with high cation disorder experience a comparably homogeneous fatigue process upon extended cycling, while a disordered surface with lattice mismatch is gradually formed in the NA with low cation disorder (i.e. heterogeneous degradation) which results in a rapid capacity decay during the fast charge–discharge cycling.