Novel design and preparation of N-doped graphene decorated Na3V2(PO4)3/C composite for sodium-ion batteries

Abstract

N-doped graphene (N-graphene) has been a very powerful tool to tailor the property of the pure graphene and it has been proved to be an excellent conducting matrix for preparing high-rate sodium-ion batteries. In this work, we design a facile and rapid route to fabricate the advanced cathode in which the carbon-coated Na3V2(PO4)3 nanocrystals are wrapped on the surface of N-graphene (Na3V2(PO4)3/C@N-graphene). The highly conducting N-graphene sheets significantly enhance the electrochemical performance of the composite, which presents excellent high-rate capability and long-cycle stability. The initial specific capacity of the composite can be up to 115.2mAhg−1 at 0.1C between 2.5 and 3.8V, which is approximately 97.6% of the theoretical capacity. Moreover, the composite shows a long-cycle performance exceeding 1000cycles at high rate of 15C and a high capacity retention ratio. These superior electrochemical properties could be ascribed to many reasons, including the superior electronic conductivity of N-graphene matrix and the nanosized Na3V2(PO4)3/C particles, which are helpful for the transport of e− and Na+. The results demonstrate that the Na3V2(PO4)3/C@N-graphene is a promising candidate to be used in sodium-ion batteries.