Solvothermal synthesis of uniform Li3V2(PO4)3/C nanoparticles as cathode materials for lithium ion batteries

A uniform precursor of Li₃V₂(PO₄)₃ nanoparticles was synthesised by a solvothermal method using ethanolamine lactate as both solvent and carbon sources at ambient pressure. Nanostructured Li₃V₂(PO₄)₃/C cathode materials could be successfully prepared by subsequent heat treatment. The scanning and transmission electron microscopy observation shows that the as-synthesised Li₃V₂(PO₄)₃/C powders retained the morphology and the particle size of the precursor that was formed during the solvothermal process. The Li₃V₂(PO₄)₃ particles are coated with uniform carbon layers with a thickness of about 5 nm. The material presents excellent performance with a high-rate capacity and cycle stability. It can deliver discharge capacities of 127.9, 117.7, 104.9 and 95.6 mAh g^-1 in the potential ranges of 3.0-4.3 V, 164.0, 154.8, 141.0 and 131.1 mAh g^-1 between 3.0 and 4.8 V corresponding to 0.5, 1, 5 and 10 C rate after cycles, respectively. The charge transfer impedance increases from 55.55 to 127.31 Ω after 50 cycles at 1.0 C, which is attributed to the refined structure and the uniform carbon film on the surface of the as-prepared Li₃V₂(PO₄)₃/C powders.