Preparation and electrochemical performance of 7LiFePO4·3Li3V2(PO4)3/C

•A modified solid state method was applied to prepare 7LiFePO4·3Li3V2(PO4)3/C.•Carbon film in-situ grows among 7LiFePO4·3Li3V2(PO4)3 particles.•7LiFePO4·3Li3V2(PO4)3/C has a capacity of 92 mAh g−1 at current of 1700 mA g−1.

7LiFePO4·3Li3V2(PO4)3/C is prepared by a solid state method with sucrose as carbon source. A sucrose liquefying process at 180 °C is applied to make liquid sucrose spread on the surface of solid particles. HRTEM shows carbon film with high crystallinity are formed among 7LiFePO4·3Li3V2(PO4)3 material. This material shows excellent rate performance, at the current density of 17 mA g−1, its specific capacity is 152 mAh g−1, which can be 92 mAh g−1 when the current density is increased to 1700 mA g−1. If no heat-treatment step at 180 °C, the 7LiFePO4·3Li3V2(PO4)3 material only has the discharge capacity of 69 mAh g−1 at 1700 mA g−1.