Enhancing sodium-ion batteries performance enabled by three-dimensional nanoflower Sb2S3@rGO anode material

Sodium-ion batteries (SIBs) gradually become ideal substitutes to lithium-ion batteries (LIBs) as a result of higher applicability in new-generation energy storage system. However, the controlled preparation of superior electrode materials for obtaining high-performance SIBs remains a challenge. In this study, a composite structure comprising three-dimensional nanoflower Sb2S3 and reduced graphene oxide (rGO) was successfully manufactured by applying a hydrothermal method as an emerging anode material for SIBs. Nanoflower Sb2S3@rGO exhibited excellent electrochemical performance, yielding 544.8 mAh/g at a rate of 100 mA/g, and sustained stability in the later 200 cycles, which was 75.4% of the initial value for the specific capacity. Even the current density is 2000 mA/g, a specific energy capacity of 433.4 mAh/g was obtained. The sodium storage mechanism was explored using cyclic voltammetry at different sweep speeds to clearly point out the electrochemical process of forming nanoflower Sb2S3@rGO. The results indicate that the high performance is ascribed to the particular flower-like three-dimensional structure, which provides cache space for Sb2S3 volume expansion during charge/discharge, while the addition of rGO effectively improves the overall electrical conductivity of the electrode. This work furnishes a new insight into the construction of specially structured anode materials to promote the development of SIBs.