Controllable Design of MoS2 Nanosheets Anchored on Nitrogen‐Doped Graphene: Toward Fast Sodium Storage by Tunable Pseudocapacitance

Abstract

Transition‐metal disulfide with its layered structure is regarded as a kind of promising host material for sodium insertion, and intensely investigated for sodium‐ion batteries. In this work, a simple solvothermal method to synthesize a series of MoS 2 nanosheets@nitrogen‐doped graphene composites is developed. This newly designed recipe of raw materials and solvents leads the success of tuning size, number of layers, and interplanar spacing of the as‐prepared MoS 2 nanosheets. Under cut‐off voltage and based on an intercalation mechanism, the ultrasmall MoS 2 nanosheets@nitrogen‐doped graphene composite exhibits more preferable cycling and rate performance compared to few‐/dozens‐layered MoS 2 nanosheets@nitrogen‐doped graphene, as well as many other reported insertion‐type anode materials. Last, detailed kinetics analysis and density functional theory calculation are also employed to explain the Na+‐ storage behavior, thus proving the significance in surface‐controlled pseudocapacitance contribution at the high rate. Furthermore, this work offers some meaningful preparation and investigation experiences for designing electrode materials for commercial sodium‐ion batteries with favorable performance.