Controllable synthesis of high-rate and long cycle-life Na3V2(PO4)3 for sodium-ion batteries

Three different morphologies, irregular shaped, the porous sponge-like and plate like of Na3V2(PO4)3, were synthesized by controlling the amount of oxalic acid using a simple and low cost two step reduction method. The results indicated that the as-prepared Na3V2(PO4)3 samples exhibit considerable morphology dependent electrochemical performance. The porous sponge-like Na3V2(PO4)3 displays an excellent cyclability and rate performance from 101.77 to 89.28 mAh g−1 at 30 C after 700 cycles, from 99.09 to 80.23 mAh g−1 at 50 C after 600 cycles, as well as from 91.50 to 84.70 mAh g−1 at 70 C after 500 cycles.204