A study on the electrochemical characteristics of LiFePO4 cathode for lithium polymer batteries by hydrothermal method

Abstract Phospho-olivine LiFePO 4 cathode materials were prepared by hydrothermal reaction at 150 °C. Carbon black was added to enhance the electrical conductivity of LiFePO 4 . LiFePO 4 -C powders (0, 3, 5 and 10 wt.%) were characterized by X-ray diffraction (XRD) and transmission electron microscope (TEM). LiFePO 4 -C/solid polymer electrolyte (SPE)/Li cells were characterized electrochemically by charge/discharge experiments at a constant current density of 0.1 mA cm −2 in a range between 2.5 and 4.3 V vs. Li/Li + , cyclic voltammetry (CV) and ac impedance spectroscopy. The results showed that initial discharge capacity of LiFePO 4 was 104 mAh g −1 . The discharge capacity of LiFePO 4 -C/SPE/Li cell with 5 wt.% carbon black was 128 mAh g −1 at the first cycle and 127 mAh g −1 after 30 cycles, respectively. It was demonstrated that cycling performance of LiFePO 4 -C/SPE/Li cells was better than that of LiFePO 4 /SPE/Li cells.