Facile synthesis of ultrathin MoS2/C nanosheets for use in sodium-ion batteries

Abstract

We present a clean and simple method for the synthesis of MoS₂/C hybrids. Commercial ion-exchange resins are used to absorb aqueous molybdate, followed by annealing with sulfur powder in an inert atmosphere. Even ultrathin MoS₂ nanosheets with enlarged interlayers (0.63 nm) are homogeneously wrapped by mesoporous graphitic carbon. When evaluated as anodes for sodium-ion batteries, the MoS₂/C nanocomposite exhibits good electrochemical performance. The first discharge/charge capacities at current density 50 mA g⁻¹ are 784.3 and 590.0 mA h g⁻¹, respectively, with initial coulombic efficiency of approximately 75%. It exhibits superior rate capabilities, with specific discharge capacities of 513.1, 467.3, 437.1, 399.2, 361.8, and 302.7 mA h g⁻¹ at current densities of 50, 100, 200, 500, 1000, and 2000 mA g⁻¹, respectively. This superior electrochemical performance is mainly due to the synergistic effect between the uniformly-distributed, ultrathin MoS₂ nanosheets and the highly graphitized carbon. This not only mitigates mechanical stress during repeated cycling, but also provides good conductivity.