Tin Disulfide Nanosheets with Active-Site-Enriched Surface Interfacially Bonded on Reduced Graphene Oxide Sheets as Ultra-Robust Anode for Lithium and Sodium Storage

Two-dimensional (2D) tin disulfide (SnS2) has attracted intensive research owing to its high specific capacity for Li and Na storage, natural abundance, as well as environmental friendliness. However, the poor reaction kinetics, low intrinsic electrical conductivity, and severe volumetric variation upon cycling processes of SnS2 impede its widespread application. In this work, SnS2 nanosheets with active-site-enriched surface intimately grown on reduced graphene oxide (rGO) via C-O-Sn chemical bonds are prepared. The aligning affords more active sites for electrode reaction and short transport pathways for Li+/Na+ and electrons. The strong chemical bonding enhances the interfacial affinity of SnS2 with rGO and inhibits the detachment of active SnS2 from rGO during repeated charge and discharge processes, which can ensure an integrated electrode structure. The 3D conductive and flexible rGO network improves the conductivity of the entire composite and buffers the volume change of SnS2 upon charge/discharge. These advantages enable the designed SnS2/rGO nanocomposite to have high specific capacity, superior rate capability, and outstanding long-cycling stability for both Li and Na storage.