Vacancy-induced sodium-ion storage in N-doped carbon Nanofiber@MoS2 nanosheet arrays

As a promising material for sodium-ion batteries, molybdenum disulphide (MoS2) affords excellent electrochemical performance owing to its large surface area and the accelerated electron transport within individual layers. However, it suffers from slow reaction kinetics and agglomeration owing to low conductivity and high surface energy. In this work, nitrogen-doped carbon nanofiber@MoS2 nanosheets arrays with S-vacancies (NC@MoS2-VS) are developed via a process involving electrospining, hydrothermal and annealing. When served as an anode material for SIBs, this material displays a superior capacity of 495 mAh g−1 over 100 charge/discharge cycles at a current density of 100 mA g−1, and the pseudocapacitive contribution is up to 74.4% as revealed by the cyclic voltammogram (CV) at 1 mV s−1. The theoretical calculations show that the presence of sulfur vacancies facilitates the adsorption of Na+ and enhances the conductivity of MoS2. This work may pave a new avenue to develop other types of metal sulfides for high-performance SIBs.