Electrochemical properties of the carbon-coated LiFePO 4 as a cathode material for lithium-ion secondary batteries

Abstract

In this study the effect of the carbon coating on the electrochemical properties of LiFePO 4 as a cathode for Li-ion batteries were investigated. The carbon-coated LiFePO 4 particles were synthesized by the mechanochemical process and one-step heat treatment. Microscopic observations using SEM and TEM revealed that the carbon coating reduced the particle size of the LiFePO 4. The carbon-coated LiFePO 4 showed much better performances in terms of the discharge capacity and cycle stability than bare LiFePO 4. It was confirmed that the carbon coating decreased the migration distance of Li-ion and enhanced the charge transfer from CV and ac impedance measurements. The improved electrochemical properties of the carbon-coated LiFePO 4 were, therefore, attributed to the reduced particle size and enhanced electrical contacts by carbon.