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 degrees 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 degrees 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 perfortriance cathode material for Li-ion battery. (c) 2006 Elsevier B.V All rights reserved.