One‐Step Sintering Synthesis Achieving Multiple Structure Modulations for High‐Voltage LiCoO<sub>2</sub>
Hengyu Ren, Wenguang Zhao, Haocong Yi, Zhefeng Chen, Haocheng Ji, Jun Qi, Wangyang Ding, Zijian Li, Mingjie Shang, Jianjun Fang, Ke Li, Mingjian Zhang, Shunning Li, Qinghe Zhao, Feng Pan
Abstract
Abstract The structure instability issues of the highly delithiated LiCoO 2 have significantly hindered its high‐voltage applications (≥4.55 V vs Li/Li + ). Herein, for the first time, multiple modifications of Li 0.9 Mg 0.05 CoO 2 (L 0.9 M 0.05 CO) via a simple one‐step sintering synthesis are reported. A combination of the bulk Li/Co antisites, a Mg‐pillar enriched surface, and a thin MgO coating layer is achieved to maintain both the bulk and surface structural stability of L 0.9 M 0.05 CO upon cycling at an upper cut‐off voltage of 4.6 V. The bulk Li/Co antisites are discovered to enhance the H1‐3 phase evolution reversibility, the Mg pillars that substitute the Li sites effectively reinforces the surface structure, and the thin MgO coating layer can effectively prevent the cathode from severe side reactions. Benefiting from the reduced but reversible H1‐3 phase transition and the reinforced surface structure, L 0.9 M 0.05 CO shows an excellent cycle stability. This work provides a new structure modulation route for developing high‐voltage LiCoO 2 cathodes.