Graphene-supported Na3V2(PO4)3 as a high rate cathode material for sodium-ion batteries

Substantial interest in sodium resources that are inexpensive and abundant in the earth has guided intense research on Na-based electrode materials. We report a facile synthetic strategy to improve the rate performance of Na-based electrode materials in sodium-ion batteries. Na3V2(PO4)3 (NVP) is one of the most promising cathode materials with a NASICON structure, and it has been synthesized on a graphene sheet surface using a simple method that combines sol–gel and solid-state reaction. The NVP/graphene composite displays an excellent high-rate performance; it delivers approximately 67% of the initial 0.2 C capacity at a 30 C rate, whereas bare NVP produces only 46% of the 0.2 C capacity at a 5 C rate. It also demonstrates high capacity retention both at 1 C and 10 C cycles as a promising cathode for rechargeable sodium-ion batteries. This outstanding result can be ascribed to the key role of graphene in enhancing the electronic conductivity of electrode materials compared with bare NVP.