Pushing Lithium Cobalt Oxides to 4.7 V by Lattice‐Matched Interfacial Engineering
Xuerui Yang, Chuanwei Wang, Pengfei Yan, Tianpeng Jiao, Jialiang Hao, Yuyuan Jiang, Fucheng Ren, Wenguang Zhang, Jianming Zheng, Yong Cheng, Xianshu Wang, Wen Yang, Jianping Zhu, Siyu Pan, Min Lin, Leiying Zeng, Zhengliang Gong, Jun‐Tao Li, Yong Yang
Abstract
Abstract The utilization of high‐voltage LiCoO 2 is imperative to break the bottleneck of the practical energy density of lithium‐ion batteries. However, LiCoO 2 suffers from severe structural and interfacial degradation at > 4.55 V. Herein, a novel lattice‐matched LiCoPO 4 coating is rationally designed for LiCoO 2 which works at 4.6 V (vs Li/Li + ) or above. This LiCoPO 4 coating, derived by an in situ chemical reaction, grows epitaxially on LiCoO 2 crystallite with strong bonding and complete coverage to LiCoO 2 , ensuring a stable cathode–electrolyte interface with fewer side reactions and alleviated intergranular cracking and phase collapse during repeated high‐voltage lithiation/delithiation processes. In addition, the formed strong covalent P–O tetrahedron configuration at the interface effectively decreases the surface oxygen activity of LiCoO 2 , further suppressing oxygen release and irreversible phase transition. Therefore, the LiCoPO 4 ‐LiCoO 2 ǁLi cells display excellent capacity retention of 87% after 300 cycles at 4.6 V and stable operation at 4.6 V/55 ° C or 4.7 V/30 ° C. The strategy of lattice‐matching growth affords a new way to impact the development of high‐voltage LiCoO 2 and beyond.