Synthesis of novel high-voltage cathode material LiCoPO 4 via rheological phase method

Abstract

For the first time, rheological phase method, a simple and effective route, is applied to synthesize novel cathode material LiCoPO 4. X-ray diffraction spectrometer (XRD), X-ray photoelectron spectrometer (XPS), transmission electron microscope (TEM) and electrochemical impedance spectroscopy (EIS) are taken to investigate this material, respectively. XRD figure shows that the rheological sample is better crystallized than the solid-state one. XPS result of the rheological sample exhibits that the valence of Co is 2+. TEM images show that better dispersed particles with smaller size can be formed by rheological method comparing to the solid-state route. Charge–discharge test is carried out in the range of 3.0–5.0 V at 0.2 mA cm −2. The initial discharge capacity for rheological phase and solid-state powder is 71.5 and 30.9 mAh g −1, respectively. The better electrochemical property should be ascribed to the better crystallized rheological phase production with better dispersed and smaller particles, which can greatly facilitate the diffusion of Li +.