EFFECT OF CARBON SOURCE ON ELECTROCHEMICAL PERFORMANCE OF CARBON COATED LiMnPO4 CATHODE

Source materials for carbon coating on LiMnPO4 were examined to improve the electrochemical performance of LiMnPO4. L-ascorbic acid, sucrose, polyethylene oxide (PEO), and carboxymethyl cellulose (CMC) were used as carbon sources for hydrothermal synthesis of the carbon coated LiMnPO4. Disordered (D) and graphite-like (G) carbons were detected by Raman spectroscopy for the prepared samples except for the sample using PEO, and the highest G/D ratio was obtained for the sample prepared using CMC as carbon source. The electrochemical performance of the samples was evaluated by a galvanostatic charge/discharge test. The carbon coated LiMnPO4 prepared with CMC carbon source showed the highest discharge capacity, 94 mA h/g at 0.01 C (corresponding to 55% of the theoretical capacity, 171 mA h/g), indicating that the carbon sources greatly influenced the electrochemical performance of carbon coated LiMnPO4 prepared by hydrothermal synthesis.