Preparation of dense LiFePO4/C composite positive electrodes using spark-plasma-sintering process

Composite positive electrodes LiFePO4/C, applicable for rechargeable lithium-ion batteries cycled at high current density, were prepared using spark-plasma-sintering (SPS) technique. LiFePO4/C composite positive electrodes with carbon content of 20 wt.% was synthesized at 600 degrees C in the SPS process, and it was found that LiFePO4 particles were covered with fine carbon particles and they formed agglomerates with the size of about 10 mu m. It resulted in higher electrode density. Charge/discharge tests for the cell using LiFePO4/C composite positive electrodes showed superior cycle performance at the rates of 17-850 mAh g(-1) (0.1-5 C) compared with the cell using the conventionally blended LiFePO4 + C composite positive electrodes. The improvement of the cell performance was attributed to strong binding between LiFePO4 and carbon powders. Consequently, the electrical network remained almost unchanged during electrochemical redox cycling, even at high current rates. (c) 2005 Elsevier B.V. All rights reserved.