Effect of LiFePO4 coating on electrochemical performance of LiCoO2 at high temperature

LiFePO4 coating on LiCoO2 with a thickness ranging 10–100 nm improved the electrochemical performance of the cathode material at high temperature and high potential. At 60 °C and at a rate of 1 C, 5.0 wt.% LiFePO4-coated LiCoO2 showed better capacity retention (132 mAh/g) with 4.2 V charge-cutoff after 250 cycles, while the bare cathode (pure LiCoO2) showed 5% capacity retention under the same conditions after only 150 cycles. When cycled at 60 and 75 °C, the amount of Co dissolution from LiCoO2 was greatly reduced in the LiFePO4-coated cathode material. The coating layer of LiFePO4 not only protects the LiCoO2 but also serves as an active cathode material with good conductivity. The LiFePO4-coated LiCoO2 could be a high performance cathode material for Li-ion battery.