Sandwich-like SnS/graphene multilayers for efficient lithium/sodium storage.

2D materials have attracted extensive attention in energy storage and conversion due to their excellent electrochemical performances. Herein, we report utilization of monolayer SnS sheets within SnS/graphene multilayers for efficient lithium and sodium storage. SnS/graphene multilayers are synthesized through a solution-phase direct assembly method by electrostatic interaction between monolayer SnS and PDDA (polydimethyl diallyl ammonium chloride)-graphene nanosheets. It has been shown that the SnS/graphene multilayer electrode has a large pseudocapacity contribution for enhanced lithium and sodium storage. Typical batteries deliver a stable reversible capacity of ∼160 mA h g at 2 A g after 2000 cycles for lithium and a stable reversible capacity of ∼142 mA h g at 1 A g after 1000 cycles for sodium. The excellent electrochemical performances of SnS/graphene multilayers are attributed to the synergistic effect between the monolayer SnS sheets and the PDDA-graphene nanosheets. The multilayer structure assembled by different monolayer nanosheets is promising for the further development of 2D materials for energy storage and conversion.