Effect of carbon source as additives in LiFePO4 as positive electrode for lithium-ion batteries

The electrochemical properties of LiFePO4 cathodes with different carbon contents were studied to determine the role of carbon as conductive additive. LiFePO4 cathodes containing from 0 to 12% of conductive additive (carbon black or mixture of carbon black and graphite) were cycled at different C rates. The capacity of the LiFePO4 cathode increased as conductive additive content increased. Carbon increased the utilization of active material and the electrical conductivity of electrode, but decreased volumetric capacity of electrode. This composition (LiFePO4 with 3 wt % of carbon and 3 wt % of Graphite) is suitable for HEV application. (C) 2005 The Electrochemical Society.