Nano Sn2S3 Embedded in Nitrogenous-Carbon Compounds for Long-Life and High-Rate Cycling Sodium-Ion Batteries

Metallic tin (Sn) compounds are viewed as promising candidates for sodium-ion batteries (SIB) anode materials yet suffer from large volume expansion and limited electrode kinetics. Manufacturing rational structure is a crucial factor to achieve high-efficiency sodium storage for SIBs. In this study, nano Sn2S3 embedded in nitrogenous-carbon compounds (nano-Sn2S3/C) was designed for SIB anode materials via a facile three-step strategy: precipitation, heat treatment and vulcanization with no templating agent. Density functional theory calculations suggested that Sn2S3 displayed a low Na+ diffusion energy barrier and the Sn-S bonds could be rebuilt during the sodiation/de-sodiation process. Notably, electrochemical measurements coupled with ex-situ X-ray diffraction and ex-situ transmission electron microscopy were proposed to reveal the underlying Na+ storage mechanisms. Sn2S3 acted as a high-capacity composition, while the porous nitrogenous-carbon matrix served as a rigid-conductive frame to accommodate the volume expansion and prevented the aggregation of nano Sn2S3. The rationally generated architectures benefited greatly in rate capacity and structural stability. As expected, the as-prepared nano Sn2S3/C exhibited remarkable rate capabilities with a specific capacity of 603 and 160 mAh g(-1) under typical conditions at 0.2 and 4 A g(-1), respectively. This work may trigger new enthusiasm for engineering high-performance SIB anode materials.

Automated summary

The study successfully synthesized nano-Sn2S3/C composites as anode materials for sodium-ion batteries through rational structure design, which showed excellent Na+ diffusion and bond reconstruction properties according to density functional theory calculations. The electrochemical tests and in-situ experiments revealed the sodium storage mechanisms, demonstrating the promising performance of the materials.