Rationally designed heterostructure ZnS/SnS@N-doped carbon microspheres as high-performance anode for lithium-ion batteries

Abstract

Metal sulfides are considered as promising anodes for lithium-ion batteries (LIBs) because of their high capacity. Among all of these metal sulfides, Tin(II) sulfide (SnS), possessing a unique 2D structure and with high lithium storage capacity, attract more attention as a promising anode for LIBs. However, serious volume change, sluggish kinetics, and low electric conductivity during the charging/discharging process, lead to poor rate capability and fast capacity fading. Herein, a ZnS/[email protected] yolk-shell microspheres ([email protected]) is synthesized through a facile hydrothermal process coupled with a PPy coating and sulfidation-in-microsphere strategy. The built-in electric field generated from ZnS/SnS heterostructure benefits the rapid transport of Li-ion and enhances the electric conductivity. Meanwhile, the N-doped carbon further improves the electronic conductivity and provides a robust support architecture, which can mitigate the volume variation of ZnS/SnS during the lithiation/delithiation process. Therefore, the ZnS/[email protected] delivers high capacity (775.5 mA h g−1 at 200 mA g−1 after 200 cycles), outstanding rate performance (395.8 mA h g−1 at 5 A g−1), and superior long-term cycling performance (571.2 mA h g−1 at 1 A g−1 after 1000 cycles).