Ionic conductor cerous phosphate and carbon hybrid coating LiFePO4 with improved electrochemical properties for lithium ion batteries

Novel cerous phosphate and carbon hybrid coating LiFePO4 cathode material successfully synthesized via liquid-phase precipitation reaction combined with the high temperature solid state method have been studied in lithium ion batteries. LiFePO4 deposited an appropriate amount of cerous phosphate in carbon coating layer shows higher reversible capacity and stable cycle performance compared with the LiFePO4/C. The good conductivity and stability of the hybrid coating layer can be favorable for these properties of LiFePO4, which increase Li+ ion and electronic transport on the surface and into the bulk of LiFePO4 electrode, avoid HF dissolving LiFePO4 in electrolyte, and facilitate the transfer kinetics. LiFePO4/C–CePO4 (1.0 mol%) electrode exhibits a stable cyclability and the highest capacity among all the LiFePO4/C–xCePO4 samples. The initial discharge capacity of LiFePO4/C–CePO4 (1.0 mol%) is 166.1, 161.4, 143.7 and 120.3 mAh g−1 at 1, 2, 5 and 10 C rates, respectively. And the capacity retention remains as high as 77.5% even after 650 cycles at 10 C. In addition, the material shows a higher reversible specific capacity of 100.9 mAh g−1 under lower discharging rate at −20 °C.