Synthesis of LiCoPO₄ as cathode material for lithium-ion batteries by the rheological phase method

LiCoPO₄ has been successfully synthesized by a simple rheological phase method. The effects of synthesis temperature on the properties of LiCoPO₄ are also investigated. The results show that a well-crystallized olivine structure LiCoPO₄ with no obvious impurity phase is obtained. The electrochemical properties of LiCoPO₄ were examined by galvanostatic charge/discharge tests, cyclic voltammetry (CV), and electrochemical impedance spectroscopy (EIS). The results indicate that the sintering temperature has a significant effect on the electrochemical properties of LiCoPO₄. The sample fired at 600 °C shows the best electrochemical properties. The initial discharge capacity is 101.0, 96.8, and 91.6 mAh g⁻¹ at 0.1, 0.2, and 1 C, respectively. The significantly improved electrochemical properties of LiCoPO₄ are attributed to the better crystallized rheological phase production with better dispersed and smaller particles, which can greatly facilitate the diffusion of Li⁺.