Rate performance of Li ₃V ₂(PO ₄) ₃/C cathode material and its Li ⁺ ion intercalation behavior

Rate performance and kinetic properties of Li ₃V ₂(PO ₄) ₃/C composite electrode have been investigated in this paper. The Li ₃V ₂(PO ₄) ₃/C composite obtained via a rheological phase method displays a monoclinic structure with an average particle size of ca. 200-300 nm. Electrochemical tests show this material exhibits good reversibility and excellent rate capability up to a current density of 3373 mA g ^-1 (30 C). The composite material achieves its theoretical capacity at 1 C rate. The capacity loss is less than 4% from 1 to 10 C. Even at the highest 30 C rate, the capacity is above 100 mAh g ^-1. The kinetic properties of the composite electrode are analyzed by cyclic voltammetry (CV) and potentiostatic intermittent titration (PITT) techniques. The Li ⁺ ion diffusion coefficients calculated from PITT are in the range of 10 ^-7-10 ^-8 cm ² s ^-1.