Role of Substitution Elements in Enhancing the Structural Stability of Li-Rich Layered Cathodes

作者：Zhang, Baodan; Zhang, Yiming; Wang, Xiaotong; Liu, Hui; Yan, Yawen; Zhou, Shiyuan; Tang, Yonglin; Zeng, Guifan; Wu, Xiaohong; Liao, Hong-Gang; Qiu, Yongfu; Huang, Huan; Zheng, Lirong; Xu, Juping; Yin, Wen; Huang, Zhongyuan; Xiao, Yinguo; Xie, Qingshui; Peng, Dong-Liang; Li, Chao^*; Qiao, Yu^*; Sun, Shi-Gang

来源：Journal of the American Chemical Society, 2023, 145(15): 8700-8713.

DOI：10.1021/jacs.3c01999

• REDOX ACTIVITY
• LITHIUM
• PERFORMANCE
• DEGRADATION
• ORIGIN

Element doping/substitution has been recognized as an effective strategy to enhance the structural stability of layered cathodes. However, abundant substitution studies not only lack a clear identification of the substitution sites in the material lattice, but the rigid interpretation of the transition metal (TM)-O covalent theory is also not sufficiently convincing, resulting in the doping/substitution proposals being dragged into design blindness. In this work, taking Li1.2Ni0.2Mn0.6O2 as a prototype, the intense correlation between the "disordered degree" (Li/Ni mixing) and interface-structure stability (e.g., TM-O environment, slab/lattice, and Li+ reversibility) is revealed. Specifically, the degree of disorder induced by the Mg/Ti substitution extends in the opposite direction, conducive to sharp differences in the stability of TM-O, Li+ diffusion, and anion redox reversibility, delivering fairly distinct electrochemical performance. Based on the established paradigm of systematic characterization/analysis, the "degree of disorder" has been shown to be a powerful indicator of material modification by element substitution/doping.

• 单位
  中国科学院; 厦门大学; 北京大学; y; 东莞理工学院