Fluorine doped carbon coating of LiFePO4 as a cathode material for lithium-ion batteries

The present work presents an insightful study on the effect of fluorine doped carbon (FC) modification on the electrochemical performance of LiFePO4 cathode material. To this end, polyvinylidene fluoride is used as fluoride source to synthesize FC, which is designed to coat on LiFePO4 surface with formation of LiFePO4@FC nanocomposites. The microstructure and electrochemical properties of the nanocomposites are systematically examined by various characterization techniques, revealing that FC is tightly attached on surface of LiFePO4 particles forming a three dimensional (3D) conductive network structure. Such favorable structure provides advantages of good grain-to-grain electrical contact, shortening the Li+ diffusion distance between the grain interfaces, and facilitating the rapid transfer of electrons during charge–discharge. The optimal LiFePO4@FC nanocomposites, i.e., with 97.2 wt% of LiFePO4, are verified to show highly desirable electrochemical performance with superior rate capability and excellent cycling performance as the cathode material of lithium-ion batteries.