Heterostructured SnS-ZnS@C hollow nanoboxes embedded in graphene for high performance lithium and sodium ion batteries

Metal sulfides are promising anode materials for lithium ion batteries (LIBs) and sodium ion batteries (SIBs) owing to their high theoretical capacity and good reaction reversibility upon lithiation/delithiation and sodiation/desodiation. However, the practical application of metal sulfides is severely hindered by its poor conductivity and huge volume change during cycling. Herein, a three dimensional hierarchical architecture is rational designed and synthesized through incorporating ZnS-SnS heterostructure encapsulated by carbon shell into graphene matrix. The interconnected conductive networks from the graphene skeleton and outer coating carbon can not only provide a high efficient transfer path for electron and ion, but also accommodate the volume variation effectively upon charging/discharging. Additionally, the in-situ constructed ZnS-SnS heterostructures provide extra charge transfer driving force because of a built-in electric field. Consequently, the as obtained ZnS-SnS@C hollow nanoboxes wrapped by grpahene show high specific capacity, long cycle lifetime and excellent rate performance when applied for anodes of LIBs and SIBs.