Implanting Cation Vacancies In Ni-Fe Ldhs For Efficient Oxygen Evolution Reactions Of Lithium-Oxygen Batteries

The main performance limitation of lithium-oxygen (Li-O-2) batteries is the formation of the insulating discharge product lithium peroxide (Li2O2), which results in high charging overpotentials and poor cycle stability. Here, NiFe layered double hydroxides (LDHs) with Ni vacancies (Ni-Fe LDHs-VNi) are employed as cathode catalysts for Li-O-2 batteries. The battery with Ni-Fe LDHs-VNi cathodes implements excellent performances for the oxygen evolution reaction (OER) process. According to density functional theory (DFT) calculations, the rate determining step of OER processes of Ni-Fe LDHs-VNi is the oxidation process of lithium superoxide (LiO2), and the high adsorption strength towards LiO2 by Ni vacancies lead to a lower charge overpotential than that of pure NiFe LDHs without vacancies. This work provides a strategy to rationally design cathode catalysts with layered structures for high-performance Li-O-2 batteries.