Pushing Lithium Cobalt Oxides to 4.7 V by Lattice‐Matched Interfacial Engineering.

The utilization of high‐voltage LiCoO2 is imperative to break the bottleneck of the practical energy density of lithium‐ion batteries. However, LiCoO2 suffers from severe structural and interfacial degradation at >4.55 V. Herein, a novel lattice‐matched LiCoPO4 coating is rationally designed for LiCoO2 which works at 4.6 V (vs Li/Li+) or above. This LiCoPO4 coating, derived by an in situ chemical reaction, grows epitaxially on LiCoO2 crystallite with strong bonding and complete coverage to LiCoO2, 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 LiCoO2, further suppressing oxygen release and irreversible phase transition. Therefore, the LiCoPO4‐LiCoO2ǁLi 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 LiCoO2 and beyond. [ABSTRACT FROM AUTHOR]