Engineering sulfur defective Bi2S3@C with remarkably enhanced electrochemical kinetics of lithium-ion batteries

Abstract

Introducing the appropriate vacancies to augment the active sites and improve the electrochemical kinetics while maintaining high cyclability is a major challenge for its widespread application in electrochemical energy storage. Here, core–shell structured Bi2S3@C with sulfur vacancies was prepared by hydrothermal method and one-step carbonization/sulfuration process, which significantly improves the intrinsic electrical conductivity and ion transport efficiency of Bi2S3. Additionally, the uniform protective carbon layer around surface of composite maintains structural stability and effectively alleviates volume expansion during alloying/dealloying. As a result, the BSC-500 anode exhibits a brilliant reversible capacity of 636 mAh/g at 0.2 A/g and a long-term stable capacity of 524 mAh/g for 500 cycles at a high current density of 3 A/g in lithium-ion batteries. In addition, the assembled Bi2S3@C//LiCoO2 full cell delivered a capacity of 184 mAh/g at 1 A/g and excellent cyclability (125 mAh/g after 1000 cycles). The proposed strategy of combining sulfur vacancies with a core–shell structure to improve the electrochemical kinetics of Bi2S3 in lithium-ion batteries off the prospect for practical applications of transition metal sulfide anodes.