Mechanochemically Robust LiCoO2 with Ultrahigh Capacity and Prolonged Cyclability

• Published in: Advanced materials (Weinheim) 2024-08, Vol.36 (32), p.e2405519-n/a
• Main Authors: Huang, Weiyuan, Li, Jianyuan, Zhao, Qinghe, Li, Shunning, Ge, Mingyuan, Fang, Jianjun, Chen, Zhefeng, Yu, Lei, Huang, Xiaozhou, Zhao, Wenguang, Huang, Xiaojing, Ren, Guoxi, Zhang, Nian, He, Lunhua, Wen, Jianguo, Yang, Wanli, Zhang, Mingjian, Liu, Tongchao, Amine, Khalil, Pan, Feng
• Format: Article
• Language: English
• Subjects: Cathodes; Crack propagation; Crystal lattices; Crystal structure; Electrode materials; Electron diffraction; Electrons; Fatigue failure; fatigue resistance; Fatigue strength; gradient disordering; Imaging techniques; Lattice strain; Li-ion battery cathode; Lithium compounds; MATERIALS SCIENCE; Phase transitions; prolonged cyclability; ultrahigh capacity
• ISSN: 0935-9648; 1521-4095; 1521-4095
• DOI: 10.1002/adma.202405519

Pushing intercalation‐type cathode materials to their theoretical capacity often suffers from fragile Li‐deficient frameworks and severe lattice strain, leading to mechanical failure issues within the crystal structure and fast capacity fading. This is particularly pronounced in layered oxide cathodes because the intrinsic nature of their structures is susceptible to structural degradation with excessive Li extraction, which remains unsolved yet despite attempts involving elemental doping and surface coating strategies. Herein, a mechanochemical strengthening strategy is developed through a gradient disordering structure to address these challenges and push the LiCoO2 (LCO) layered cathode approaching the capacity limit (256 mAh g−1, up to 93% of Li utilization). This innovative approach also demonstrates exceptional cyclability and rate capability, as validated in practical Ah‐level pouch full cells, surpassing the current performance benchmarks. Comprehensive characterizations with multiscale X‐ray, electron diffraction, and imaging techniques unveil that the gradient disordering structure notably diminishes the anisotropic lattice strain and exhibits high fatigue resistance, even under extreme delithiation states and harsh operating voltages. Consequently, this designed LCO cathode impedes the growth and propagation of particle cracks, and mitigates irreversible phase transitions. This work sheds light on promising directions toward next‐generation high‐energy‐density battery materials through structural chemistry design. A high‐performance LCO cathode is developed with a gradient disordering structure design, enabling it to reach the capacity limit (up to 93% of Li utilization) while maintaining high cyclability and rate capability. Comprehensive analysis reveals this innovative structure fundamentally addresses the anisotropic lattice strain issue and exhibits remarkable fatigue resistance, even under harsh operating voltages.