Reduced Graphene Oxide Boosted Ultrafine Cu2SnS3 Nanoparticles for High-performance Sodium Storage

Ternary Sn-based sulfides have been considered as potential anode materials for sodium-ion batteries (SIBs) due to their unique composition and high theoretical specific capacities. However, such kind of materials suffers from sluggish kinetics and huge volumetric variation resulting from the large ionic size of the sodium ions during the battery operation process. Herein, we use a facile hydrothermal method to prepare Cu2SnS3/reduced graphene oxide (CTS/RGO) composite. Characterizations reveal that CTS/RGO consists of ultrafine CTS nanoparticles with uniform and small size, which are anchored uniformly on the surface of RGO sheets. Benefited from the unique structure feature, CTS/RGO has a high reversible capacity of 566.8 mA h g(-1), good cycle stability and rate capability even at a high current density of 3200 mA g(-1), which is superior to that of bare CTS. The improved performances are ascribed to the unique structure with anchoring ultrafine CTS nanoparticles on the surface of high conductive and flexible RGO sheets, which can greatly enhance electrochemical reaction kinetics and effectively alleviate volume effect of the active materials.