One pot synthesis and capacitive sodium storage properties of rGO confined CoS2 anode materials

Abstract A facile and scalable hydrothermal method is utilized to synthesize CoS2 nanooctahedrons decorated rGO hybrids with varied compositions. The as-obtained CoS2/rGO nanocomposites exhibit the morphology of nanooctahedrons with size of ∼300 nm decorated on the wrinkled rGO nanosheets, while pure CoS2 is assembled into micro-sized aggregates. By virtue of rGO, CoS2/rGO nanocomposites provide reduced diffusion length and enhanced electrical conductivity. Importantly, the CoS2/rGO-40 electrode delivers a reversible capacity of 825 mAh g−1 after 40 cycles at 0.1 A g−1. Even at 1 A g−1, it can still maintain a capacity of 658 mAh g−1 after 150 cycles. Further kinetic analysis demonstrates a more favored capacitive behavior. The superior sodium storage performance reveals that CoS2/rGO nanocomposites can be promising anodes for sodium ion batteries.