Enhancing the Electrocatalysis of LiNi0.5Co0.2Mn0.3O2 by Introducing Lithium Deficiency for Oxygen Evolution Reaction

Authors

Abstract

LiNi0.5Co0.2Mn0.3O2 (NCM523), as a cathodematerial for rechargeable lithium-ion batteries, has attractedconsiderable attention and been successfully commercialized fordecades. NCM is also a promising electrocatalyst for the oxygenevolution reaction (OER), and the catalytic activity is highlycorrelated to its structure. In this paper, we successfully obtainNCM523 with three different structures: spinel NCM synthesizedat low temperature (LT-NCM), disordered NCM (DO-NCM)with lithium deficiency obtained at high temperature, and layered hexagonal NCM at high temperature (HT-NCM). By introducinglithium deficiency to tune the valence state of transition metals in NCM from Ni2+ to Ni3+, DO-NCM exhibits the best catalyticactivity with the lowest onset potential (1.48 V) and Tafel slope (85.6 mV dec1), whereas HT-NCM exhibits the worst catalyticactivity with the highest onset potential (1.63 V) and Tafel slope (241.8 mV dec1).