Wet-chemical coordination synthesized Li₃V₂(PO₄)₃/C for Li-ion battery cathodes

Lithium vanadium phosphate (Li₃V₂(PO₄)₃) is one of the most promising cathode materials for developing practical Li-ion batteries due to its advantages of structural stability, low cost, relatively high energy density. For this purpose, a wet-chemical coordination approach has been applied to synthesis of the Li₃V₂(PO₄)₃/C (LVP/C) cathode materials for Li-ion batteries. The structure, morphology, and electrochemical and kinetic behaviors of LVP/C samples calcined at different temperatures are studied. The optimized Li₃V₂(PO₄)₃ sample calculated at 850 °C (denoted as LVP-850) exhibits excellent rate performance: at high rate of 0.5, 1, 5, 10 and 20 C, impressive specific capacity of 110.9, 106, 91.2, 83 and 43.6 mAh g⁻¹ can still be attainted, respectively. Even through it recovers back to 0.1 C, the cell can still deliver a capacity of 114.4 mAh g⁻¹ (about 97.9% of the initial capacity). Combined with cyclic voltammetry technique and ex-situ X-ray photoemission spectroscopy (XPS), the Li⁺ insertion/extraction reaction mechanisms are also confirmed. Such an efficient method plays a critical role in improving rate performance and cyclic reversibility of Li₃V₂(PO₄)₃ particles, and should also be appropriate for other functional electrode materials.