Hydrothermally prepared composite of Na3V2(PO4)2F3 with gelatin and graphene used as a high-performance sodium ion battery cathode

To improve the inherently low electrical conductivity of Na3V2(PO4)2F3, we design a three-dimensional conductive network and prepare it by hydrothermal strategy. Gelatin can reduce impurities and make the material shape more regular while graphene acts as conductive network that can improve the electrochemical properties. The prepared NVPF-gel/rGO shows a superior sodium storage performance. The reversible capacity is 125.1 mAh g-1 at 0.2 C, 108 mAh g-1 after 200 cycles, and 90.6 mAh g-1 at 5 C. Furthermore, the full cell is successfully fabricated using the hard carbon anode (average working voltage of 3.3 V). NVPF-gel/rGO composite is a potential sodium storage cathode with a good practical application prospect.