Oxygen vacancies activated porous MnO/graphene submicron needle arrays for high-capacity lithium-ion batteries

Abstract

Engineering oxygen vacancies (Ovs) in submicron transition metal oxides (TMOs) is a promising way to fabricate high-capacity anodes for lithium-ion batteries (LIBs). Herein, oxygen vacancies activated porous MnO/graphene submicron needle arrays (Ovs-MnO/G NAs) are directly grown on flexible nanoporous Cu–Mn substrate by chemical vapour deposition and hydrogen etching method, and their lithium-ion diffusion and storage mechanisms and morphology evolution are systematically investigated at submicron scale. It can be concluded that these modification strategies synergistically guarantee the fast charge transfer, effective lithium-ion diffusion and storage behaviour, and electrode structural stability. Thus, the optimal Ovs-MnO/G NAs electrode deliver a high reversible capacity of 7.7 mAh cm−2 after 100 cycles at 0.2 mA cm−2 and outstanding cycling performance of 6.12 mAh cm−2 after 500 cycles at 1.0 mA cm−2. Furthermore, the Ovs-MnO/G NAs//NCM 523 full cells also achieve high average capacities of 6.74 mAh cm−2 and cycling stability of 3.88 mAh cm−2 after 100 cycles at 0.2C, indicating its practical application value.