Interlayer-expanded MoSSe nanosheets anchored on reduced graphene oxide for high-performance sodium-ion batteries

Abstract

The structural stability and fast reaction kinetics of anodes are critical factors for applications of sodium-ion batteries (SIBs) with fast charging. Herein, the ingeniously designed MoSSe/rGO composites with large interlayer spacings (1 nm) have been synthesized by the hydrothermal reaction and selenization strategy. The synergistic effect of the expanded interlayer MoSSe nanosheets and rGO can facilitate ion diffusion and electron transmission throughout the electrode and maintain structural stability during the charge/discharge process, obtaining high-rate capability and cycling durability. Hence, the MoSSe/rGO electrodes for SIBs exhibit a reversible capacity of 518.7 mAh at 0.1 A g⁻¹ and still retain 430.5 mAh g⁻¹ with a capacity retention rate of 94.5% after 2500 cycles, even at 10 A g⁻¹. Furthermore, the full cells with pre-sodiated MoSSe/rGO as the anode and Na₃V₂(PO₄)₃@C as the cathode demonstrated discharge specific capacities of 483 mAh g⁻¹ at 0.1 A g⁻¹ and 180 mAh g⁻¹ after 400 cycles at 2 A g⁻¹. This work may pave the way for the application of high-rate capacity materials as anodes in sodium-ion batteries.