A bifunctional cerium-containing modification strategy for high-performance high-voltage LiCoO2 cathodes

Abstract

The high-voltage LiCoO₂ (LCO) cathode material (charged to 4.6 V) has attracted extensive attention due to its high capacity, yet its practical application is hindered by severe interfacial side reactions and structural degradation. Herein, we demonstrate that a dual modification strategy, featuring a Li₂CeO₃ coating with concurrent Ce doping, significantly enhances the cycling stability of LCO at 4.6 V. Specifically, cerium doping into the bulk lattice expands the interlayer spacing, while the oxygen-deficient Li₂CeO₃ coating acts as a protective barrier, facilitates lithium-ion transport, and suppresses electrolyte decomposition. This dual modification effectively suppresses lattice oxygen release and cobalt dissolution. The optimized electrode delivers a high reversible capacity of 214 mA h g⁻¹ and exhibits exceptional cycling performance with 80% capacity retention after 300 cycles at 4.6 V. It also shows remarkable rate capability (141 mA h g⁻¹ at 10C) and retains 81% of its capacity after 500 cycles at 5C.