Mg‐Pillared LiCoO 2 : Towards Stable Cycling at 4.6 V

作者：Yangyang Huang, Yangyang Huang, Yongcheng Zhu, Haoyu Fu, Mingyang Ou, Chenchen Hu, Sijie Yu, Zhiwei Hu, Chien‐Te Chen, Gang Jiang, Hongkai Gu, Lin He, Wei Luo, Yunhui Huang, Yunhui Huang · 发表于：Angewandte Chemie International Edition · 年份：2020 · DOI：10.1002/anie.202014226 · 被引用次数：277 · 研究领域：Advancements in Battery Materials、Advanced Battery Materials and Technologies、Supercapacitor Materials and Fabrication

Abstract LiCoO 2 is used as a cathode material for lithium‐ion batteries, however, cationic/anodic‐redox‐induced unstable phase transitions, oxygen escape, and side reactions with electrolytes always occur when charging LiCoO 2 to voltages higher than 4.35 V, resulting in severe capacity fade. Reported here is Mg‐pillared LiCoO 2 . Dopant Mg ions, serving as pillars in the Li‐slab of LiCoO 2 , prevent slab sliding in a delithiated state, thereby suppressing unfavorable phase transitions. Moreover, the resulting Li‐Mg mixing structure at the surface of Mg‐pillared LiCoO 2 is beneficial for eliminating the cathode‐electrolyte interphase overgrowth and phase transformation in the close‐to‐surface region. Mg‐pillared LiCoO 2 exhibits a high capacity of 204 mAh g −1 at 0.2 C and an enhanced capacity retention of 84 % at 1.0 C over 100 cycles within the voltage window of 3.0–4.6 V. In contrast, pristine LiCoO 2 has a capacity retention of 14 % within the same voltage window.