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 degrees 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. (C) 2009 Elsevier Ltd. All rights reserved.