Preparation of LiCoPO4/C nanocomposite cathode of lithium batteries with high rate performance

LiCoPO4/C nanocomposites could be successfully prepared by a combination of spray pyrolysis and wet ball-milling followed by heat treatment. X-ray diffraction analysis confirmed that the LiCoPO4/C nanocomposites were well crystallized in an orthorhombic structure with Pmna space group. Scanning electron microscopy and transmission electron microscopy with equipped energy dispersive spectroscopy verified that the LiCoPO4/C nanocomposites were the agglomerates of LiCoPO4 primary particles with a geometric mean diameter of 87 nm, and the carbon was well distributed on the surface of the agglomerates. The LiCoPO4/C nanocomposites were used as cathode active materials for lithium batteries, and the electrochemical tests were carried out for the cell Li vertical bar 1 M LiPF6 in EC:DMC= 1:1 vertical bar LiCoPO4/C at various charge-discharge rates. The cells delivered first discharge capacities of 142 and 109 mAh g(-1) at 0.05 and 20C, respectively. Furthermore, the discharge capacity after 40 cycles corresponded to 87% of initial one at 0.1 C rate. The excellent rate capability of the cells is mainly due to the well distributed carbon on the LiCoPO4 agglomerates, and a much smaller lithium ion diffusion distance in the electrode. Crown Copyright (C) 2011 Published by Elsevier B.V. All rights reserved.