Effects of carbonaceous materials on the physical and electrochemical performance of a LiFePO4 cathode for lithium-ion batteries

The effects of carbonaceous materials on the physical and electrochemical performance of LiFePO4/C hybrids are reviewed. The major role, advantages and disadvantages of carbon-based materials in LiFePO4/carbon hybrids are discussed. The introduction of an in situ grown carbon coating would be beneficial to limiting the LiFePO4 particle growth and increasing the electric conductivity. The structure and precursors of the in situ grown carbons have a great influence in the rate performance of the hybrids, which can be related to an improved electron and ion transfer rate. Deposition of LiFePO4 into a carbonaceous matrix such as a templated membrane can increase the contact area between the active materials and the electrolyte, which favors a fast ion transport. The addition of conductive carbon and graphene would only effectively increase the electrical conductivity. In order to achieve an excellent electrochemical performance of LiFePO4, it is necessary to take advantage of and to combine these approaches to optimize electron and ion transfer rates. Also, it is most important to minimize the carbon content in LiFePO4/carbon hybrids to increase volumetric energy density and tap density when practical applications in electric vehicles are targeted.