Kinetics Enhancement of High‐Voltage LCO via In‐Situ Formed Cyanide‐Rich Polymer Interfaces

Abstract Lithium cobalt oxide (LiCoO 2 ) is widely used as cathode material for lithium‐ion batteries due to its high operation voltage and high specific capacity. However, conventional LiCoO 2 (LCO) undergoes severe structural phase transitions and compositional changes at high voltage (>4.4 V) leading to failure. Herein, a multifunctional crosslinked polymer interface is insitu formed on LCO particles, which can build a nanoscale conformal coating layer on the interface of LCO, preventing the side reaction with the electrolyte. Moreover, thanks to its high‐voltage talerances and high Li + conductivity, the in‐situ polymerized interface has excellent high‐voltage stability and Li + transport kinetics, which significantly improves the electrochemical performances of LCO at 4.55 or 4.6 V. This study confirms the feasibility of in situ polymer modification of LCO, providing new ideas and methods for the structural stabilization and performance enhancement of high‐voltage lithium cobalt oxides.