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|1 M LiPF6 in EC:DMC = 1:1|LiCoPO4/C at various charge–discharge rates. The cells delivered first discharge capacities of 142 and 109 mAh g−1 at 0.05 and 20 C, 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.

► LiCoPO4/C nanocomposites could be prepared by a novel preparation method. ► They were the agglomerates of LiCoPO4 particles with a mean diameter of 87 nm. ► The carbon was well distributed on the surface of the agglomerates. ► The nanocomposite cathode delivered 142 mAh g−1 at 0.05 C and 109  mAh g−1 at 20 C. ► The discharge capacity after 40 cycles was a 87% of initial one at 0.1 C rate.