Carbon-coated Sn2S3 hollow spheres as high performance anode materials for sodium-ion batteries

Abstract

Sn-based sulfides are favorable anode materials for sodium-ion batteries (SIBs), in virtue of its high capacity, earth abundance of the constituent elements, and low cost. Sn2S3 possess an inherently high electrical conductivity (4.35 × 10−3 S cm−1) and a high theoretical capacity (1189 mA h g−1), which make it an excellent candidate material for SIB anodes. However, unlike the analogs SnS and SnS2, Sn2S3 has rarely been explored as a SIB anode due to the difficulties and complexities in its synthetic. Herein, we report the synthesis of carbon-coated Sn2S3 hollow spheres (Sn2S3@CHS) and explore its application as a SIB anode. The conductive carbon hollow spheres prevented the aggregation of Sn2S3 particles and mitigated cycling-induced strain. Furthermore, the Sn2S3 phase exhibited an intrinsic fast sodiation/de-sodiation kinetics. Owing to its unique structure, the cyclability and rate performance of Sn2S3@CHS were better than those of solid carbon-coated Sn2S3 nanoparticles (Sn2S3@CNP). At current densities of 0.1, 0.2, 0.5, and 2 A g−1, Sn2S3@CHS could deliver capacities of 645, 551, 413, and 229 mA h g−1, respectively, while the capacities of the solid Sn2S3@CNP were 271, 219, 170, and 54 mA h g−1, respectively. This study presents a new strategy in harvesting high capacity, fast-charge capabilities of tin sulfides for SIBs.