Structural engineering of metal-organic framework derived tin sulfides for advanced Li/Na storage

Tin sulfides have attracted considerable attention due to their unique layered structure, large interlayer spacing and high theoretical capacity for both lithium-ion batteries (LIBs) and sodium-ion batteries (NIBs). However, the development of tin sulfides has been limited by their poor rate capability and cycle life. To intrinsically maximize the lithium/sodium storage properties of tin sulfides, herein, a metal-organic framework (MOF) template-based strategy is developed to fabricate SnS2@C and SnS@C for LIBs, as well as 3D hollow rod-like SnS@nitrogen-doped carbon@nitrogen-doped graphene (SnS@NC@NG) to accommodate Na+ behavior in NIBs. The results show that structural/physicochemical characterization helps gain insights into the intrinsic relationships between the sulfidation temperature and crystal structures as well as lithium/sodium storage behaviors. The as-prepared SnS2@C and SnS@C exhibit superior Li+ storage behavior to SnSx-based electrodes benefiting from their unique structures (798.3 mA h g(-1) and 850.9 mA h g(-1) at 5 A g(-1) after 4000 and 5000 cycles, respectively). Particularly, the resulting SnS@NC@NG demonstrates a robust 3D hollow interacted nanostructure during sodiation/desodiation processes, showing ultrahigh specific capacity, rate capability and excellent cycle lifetimes (501.5 mA h g(-1) at 2.0 A g(-1) after 5000 cycles). This work presents a newly effective strategy to construct high-performance tin sulfide hybrids for energy storage.