Abstract:

The structure and morphology of coating carbon play an important role in improving the electronic conductivity of lithium iron phosphate. LiFePO4/C composites were synthesized using an in-situ solid state method while polypropylene and glucose were used as carbon sources. Ferrocene was used as a catalyst precursor to graphitize the pyrolytic carbon. The microstructure and morphology of lithium iron phosphate together with the amounts and structure of the coating carbon were investigated in detail. It is shown that the pyrolysis of polypropylene forms well graphitized carbon-coatings and thus improves the high-rate performance of the material. Ferrocene is effective in optimizing the carbon structure. A LiFePO4/C composite with an excellent high-rate capacity of 145 mAh·g-1 at 10C (1C=170 mA·g-1) was synthesized.

Key words: Cathode material, LiFePO4, Carbon coating, Griphitization, Ferrocene