Structural Reconstruction of Spent LiCoO2 and Regulation Mechanism of Electrocatalytic Oxygen Evolution

Abstract

Traditional recycling methods for retired lithium-ion battery cathode materials typically involve destructive metallurgical processes to extract transition metals, overlooking their intrinsic structural value. This review focuses on LiCoO2 (LCO) and emphasizes an emerging “waste-to-value” strategy: directly modifying and restructuring spent LCO into high-performance oxygen evolution reaction (OER) electrocatalysts. The formation of lithium vacancies, lattice distortions, phase transitions, and surface residues generated in spent LCO during battery long-term cycling affects the electronic structure and coordination environment of the cobalt atoms, leading to enhanced OER performance. Various modification techniques such as heteroatom doping, interface engineering, and phase reconstruction are systematically discussed. Additionally, the mechanisms of the OER process are elucidated, highlighting how different defects modulate the d-band centers, optimize the adsorption energy of oxygen intermediates, and trigger distinct reaction mechanisms. Finally, we discuss the current challenges in using spent LCO as an electrocatalyst and proposes future perspectives on its advantages, which span from half-cells to the overall water splitting process. This comprehensive review summarizes the valuable applications of converting spent LCO into electrocatalysts and provides novel insights for maximizing its residual worth.