High performance Na3V2(PO4)3 cathode prepared by a facile solution evaporation method for sodium-ion batteries

Based on its abundance and low cost, sodium based batteries have aroused extensive attention for large scale energy-storage systems. In the current work, Na3V2(PO4)3 prepared by a facile solution evaporation method (denoted as NVP-SE) is used as cathode materials for sodium ion battery, with a control sample by solid state method. Raman spectrum and TEM are used to study the carbon layer coated on NVP-SE. The results show a highly graphitization and well-coated carbon layer, which is predominant by sp2 carbon. Graphitized carbon leads to high electrical conductivity, which can improve the rate performance of Na3V2(PO4)3 materials. Besides, GITT tests show high Na-ion diffusion coefficient. Even at 30 C, the NVP-SE cathode still delivers a capacity of 70 mAh g−1. Moreover, the material also shows great long term cycling performance. After 500 cycles at 1 C rate and 1000 cycles at 5 C, its discharge capacities are still 103.3 mAh g−1 and 85.4 mAh g−1, which maintain 92.6% and 85.0% of its initial capacity. Thus, simple preparation process and excellent electrochemical performance for Na3V2(PO4)3/C extend it as a potential material for high power applications.