A new CoO/Co2B/rGO nanocomposite anode with large capacitive contribution for high-efficiency and durable lithium storage

Abstract

Transition metal oxides (TMOs) with high specific capacities are considered to be alternative anodes for up-to-date lithium-ion batteries. However, the storage mechanism of TMOs-based anodes usually refers to conversion and alloying reactions, which cause the low initial Coulombic efficiency and fast capacity decay. Here, a new proof-of-concept nanocomposite of oxides-borides combined with reduced graphene oxides (CoO/Co2B/rGO) is proposed to regulate the storage mechanism of TMOs-based anodes. Cyclic voltammogram demonstrates the increasing proportion ranging from ~60% to 90% for the capacitive contribution at varied scan rates for this nanocomposite. As expected, the as-prepared CoO/Co2B/rGO nanocomposite exhibits an enhanced initial Coulombic efficiency together with cycling stability probably for the reduced Li+ diffusion contribution occurred in conversion and alloying reactions. These findings give a new insight into improving the lithium storage property of TMOs-based anodes for LIBs.