Improved electrochemical performance of La0.7Sr0.3MnO3 and carbon co-coated LiFePO4 synthesized by freeze-drying process

Carbon coated LiFePO4 particles were first synthesized by sol–gel and freeze-drying method. These particles were then coated with La0.7Sr0.3MnO3 nanolayer by a suspension mixing process. The La0.7Sr0.3MnO3 and carbon co-coated LiFePO4 particles were calcined at 400 °C for 2 h in a reducing atmosphere (5% of hydrogen in nitrogen). Nanolayer structured La0.7Sr0.3MnO3 together with the amorphous carbon layer forms an integrate network arranged on the bare surface of LiFePO4 as corroborated by high-resolution transmission electron microscopy. X-ray diffraction results proved that the co-coated composite still retained the structure of the LiFePO4 substrate. The twin coatings can remarkably improve the electrochemical performance at high charge/discharge rates. This improvement may be attributed to the lower charge transfer resistance and higher electronic conductivity resulted from the twin nanolayer coatings compared with the carbon coated LiFePO4.