Effect of spray pyrolysis temperature on physical and electrochemical properties of LiCoPO4/C nanocomposites

Abstract

LiCoPO4/C nanocomposites could be prepared by a combination of spray pyrolysis and wet ball-milling followed by heat treatment. The effect of spray pyrolysis temperature on physical and electrochemical properties of the LiCoPO4/C nanocomposites was investigated in the range of spray pyrolysis temperature from 200 to 500°C. Single phase LiCoPO4 olivine structure could be identified by X-ray diffraction analysis for all samples. Scanning electron microscopy observation showed that all samples consisted of approximately 100nm primary particles. The LiCoPO4/C nanocomposites were used as a cathode active material for lithium batteries, and the electrochemical tests were carried out using the cell Li|1M LiPF6 in EC:DMC=1:1|LiCoPO4/C at various charge/discharge rates in a cutoff potential between 2.5 and 5.0V. The final LiCoPO4/C nanocomposite sample prepared at a spray pyrolysis temperature of 300°C exhibited the best electrochemical performance mainly due to the largest specific surface area, the smallest primary particle size and a well distributed carbon in the composites. The cells exhibited initial discharge capacities of 134mAhg−1 at 0.05°C, 128mAhg−1 at 1C and 88mAhg−1 at 10C.