Electrochemical Properties and Thermal Stability of LiNi0.8Co0.15 Al0.05O2-LiFePO4 Mixed Cathode Materials for Lithium Secondary Batteries

Abstract

ABSTRACT: We prepared various LiNi 0.8 Co 0.15 Al 0.05 O 2 -LiFePO 4 mixed-cathode electrodes by changing the con-tent of LiNi 0.8 Co 0.15 Al 0.05 O 2 and LiFePO 4 used, and we analyzed the electrochemical characteristicsof the cathodes. We found that the reversible specific capacity of the cathodes increased and thatthe capacity retention ratios of the cathodes decreased during cycling as the content ofLiNi 0.8 Co 0.15 Al 0.05 O 2 increased. Conversely, we found that although the reversible specific capacityof the cathodes decreased because of the material composition, the cycle property of the cathodesincreased when the LiFePO 4 content increased. We analyzed the thermal stability of theLiNi 0.8 Co 0.15 Al 0.05 O 2 -LiFePO 4 mixed-material cathodes by differential scanning calorimetry andfound that it increased as the LiFePO 4 content increased.Keywords: LiNi 0.8 Co 0.15 Al 0.05 O 2 , LiFePO 4 , Thermal stability, Mixed-cathode, Cycle property Received May 8, 2012 : Accepted June 22, 2012