Superior rate performance of Na3V2(PO4)3/graphene nanocomposite as a cathode material for sodium ion batteries

Abstract

Although lithium ion rechargeable batteries are dominant the mobile devices and electric vehicles in the present, there are still some limitations in terms of cost and lithium reserves in the world. In that sense, researches on Na-based electrode materials have been received considerable attention due to the abundance and low cost of sodium. However, most Na-based electrode materials have been suffered from low rate performance caused by a bigger size of Na+ compared to Li+. In order to overcome the rate problem of Na electrode materials, we present a simple synthetic approach to anchor Na3V2(PO4)3, one of several Na-based electrode materials with NASICON structure, on reduced graphene oxide (rGO) surfaces. Structural characterization by synchrotron X-ray diffraction and scanning/transmission electron microscopy shows that Na3V2(PO4)3/graphene nanocomposite is successfully synthesized with high crystallinity. This nanocomposite displays superior high-rate performance; It delivers about 88% of initial 0.1C capacity at a 10C-rate, whereas bare Na3V2(PO4)3 exhibits only 49% of 0.1C capacity at a 2C-rate. It also shows high capacity retention both at a 1C and 10C-rate as a promising cathode material for rechargeable sodium-ion batteries.