Improving the safety performance of LiNi0.5Mn1.5O4 through strategies of doping, coating and oxygen self-absorption additive

Abstract

By employing a modification strategy that involves Mg2+ doping and Cu coating on the LiNi0.5Mn1.5O4 (LNMO) cathode material, along with a composite of zeolite and graphene as an additive in conductive carbon black, we successfully develop multifunctional cathode materials with internal oxygen self-absorption capabilities. We conduct various tests, including morphology and structure analysis, oxygen release and absorption evaluation, weight loss examination, and electrochemical performance assessment, on the prepared samples. Results reveal that Mg2+ doping restrains the release of lattice oxygen from LNMO materials, thereby enhancing their structural stability. Cu coating and additives play a crucial role in absorbing released oxygen, preventing combustion, and inhibiting side reactions. The micropores of zeolite in the additive adsorb and immobilize gas molecules, reducing the release and diffusion of pyrolysis products, which exhibit flame retardancy properties. Additionally, the presence of graphene, as a highly conductive material, further improves the electrochemical performance of the cathode material. Remarkably, even after 500 cycles at a 1C rate, the modified cathode material with additives maintains a capacity of 115.03mAh⋅g−1 (93.29 % capacity retention). Overall, the demonstrated spinel-type cathode materials exhibit exceptional structural stability, thermal stability, and electrochemical performance, making them promising candidates for advanced lithium-ion batteries.