Constructing SnS/Fe2O3 heterostructure anchored on few-layered graphene as an ion-adsorption/diffusion enhancer for ultrafast and cycle-stable sodium storage

Transition-metal sulfides are emerging as appealing candidates for sodium-ion batteries (SIBs) owing to their merits of high capacities and acceptable reversibilities. Fabricating heterostructure composed of two different semiconductors has been well demonstrated to effectively tackle the key issues of large volume fluctuation and poor de-/sodation kinetics. Herein, via the in-situ vulcanization of Sn with the nanospace confinement of Fe2O3 and graphene, we have constructed the micro/nanostructured SnS/Fe2O3-G heterostructure by one-step plasma-assisted milling, in which the SnS/Fe2O3 nanoclusters are tightly anchored on few-layered graphene network. Benefiting from the built-in electric field and interfacial electronic coupling between SnS and Fe2O3 nano-components, the SnS/Fe2O3-G heterostructure is endowed with accelerated charge transfer, enhanced Na+ diffusion/adsorption kinetics, and stable electrochemical framework, greatly improving the rate capability and cyclic stability of SnS. As expected, the SnS/Fe2O3-G heterostructure anode provides high-rate capability with high capacities of 454.3/399.2 mAh/g at 5/10 A g-1, and long-term cyclic stability with high retained capacities of 442.2/386.5 mAh/g at 1/2 A g+1 for 2000 cycles. Moreover, the assembled full battery also delivers high rate (capacity ratios of 67.1 %/54.2 % at 2/5 A g+1 relative to 0.2 A g+1) and long life (high capacity retention of 94.5 % after 200 cycles at 1 A g+1). The simple strategy and fabrication method, together with the superb performance, demonstrate that the SnS/Fe2O3-G heterostructure can be a promising anode for SIBs application.