Dual conductive confinement effects on enhancing Li-ion storage of NaV6O15@VO2(M)@V2C heterojunction

Abstract

Exploring novel anode materials for lithium-ion batteries (LIBs) is always on the way due to the ever-increasing energy demands of the next generation electronic devices. Particularly, well-designed heterojunctions work wonders in realizing excellent lithium storage performance. Herein, 2D hierarchical NaV6O15@VO2(M)@V2C composites are constructed via one-step oxidation of Na-ion intercalated V2C MXene in CO2, where VO2(M) nanosheets are confined by NaV6O15 nanorods and V2C MXene. Attributed to the intrinsic merits of monoclinic VO2(M) and a dual conductive confinement system composed of the outer NaV6O15 nanorods and the inner V2C MXene, NaV6O15@VO2(M)@V2C exhibits superior electrochemical performance as an anode for LIBs. It delivers an outstanding reversible discharge capacity of 408.1 mAh g−1 at 100 mA g−1 after 100 cycles, as well as good cycling stability at 1 A g−1, which maintains capacity of 204.5 mAh g−1 after 400 cycles with a coulombic efficiency of 99.63%. This work proposes a novel insight into fabricating 2D hierarchical structure from various cation-intercalated MXenes with enhanced Li+ storage for LIBs.