Na3V2(PO4)3 nanoparticles encapsulated in carbon nanofibers with excellent Na+ storage for sodium-ion batteries

In this study, the carbon-decorated Na3V2(PO4)3 nanofibers have been prepared using a facile electrospinning route and subsequent calcination process. The formed Na3V2(PO4)3 nanoparticles are uniformly embedded in the carbon nanofibers, which can accelerate the electron and ion transport during the charge/discharge cycling. When used as cathode for sodium-ion batteries, the prepared composite displays excellent Na+ storage performances. It can deliver a high discharge capacity of 110.6 mAh g−1 at a low rate of 0.1C, which is approximately 93.7% of its theoretical capacity. Even at 5C, it also delivers an initial reversible capacity of 86.5 mAh g−1 and shows a capacity retention of 96% after 100 cycles. These superior performances can be attributed to the unique 1D nanofiber structure and the constructed carbon network, which are helpful to shorten the diffusion distance of Na+ and improve the electronic conductivity of Na3V2(PO4)3.