3D reduced graphene oxide wrapped MoS2@Sb2S3 heterostructures for high performance sodium-ion batteries

Abstract

Metal sulfides have been widely used as the anode materials of sodium-ion batteries (SIBs) due to their high theoretical capacity. However, their inherent low conductivity and irreversible volume expansion limit their electrochemical performance and application. To solve these problems, the MoS2@Sb2S3 heterostructure composites wrapped by 3D interconnected reduce graphene oxide (rGO) are prepared. The MoS2@Sb2S3 heterostructure accelerates the transfer of ions and electrons, and provides rich active sites, which facilitates electrolyte penetration and improves the interfacial reaction kinetics. Wrap 3D interconnected rGO networks around the porous MoS2@Sb2S3 composites to reduce the volume expansion of composite materials in the process of sodiumization and desodiumization, and ensure the structural stability. The theoretical calculation further supports the experimental results that the MoS2@Sb2S3/rGO heterojunction promotes the redistribution of different charge density and optimizes the adsorption energy of the composite for Na+, thus accelerating the electrochemical reaction kinetics. The MoS2@Sb2S3/rGO composite as the anode materials of SIBs can achieve a discharge specific capacity of 591.6 mAh g−1 at the second cycle with current density of 5 A g−1, and 162.1 mAh g−1 after 1100 cycles. High-rate capacities are achieved for SIBs (350.4 mAh g−1 @ 1 A g−1, 260.1 mAh g−1 @ 5 A g−1). This work provides a practical method for preparing anode materials of SIBs with excellent electrochemical performance.