Preparation of LiCoPO4 and LiFePO4 coated LiCoPO4 materials with improved battery performance

Olivine LiCoPO4 material has been successfully synthesized by solid-state reaction method without any carbon coating. The X-ray diffraction pattern shows that LiCoPO4 has a well developed orthorhombic structure with Pnma space group. The SEM analysis shows the particulate nature of the prepared materials with <200 nm size. The TEM analysis confirms that a 2-3 nm thick LiFePO4 layer is coated onto LiCoPO4. The LiFePO4 coated LiCoPO4 cell delivers a high initial discharge capacity of 132 mAhg-1, which is 19 mAhg-1 higher than the parent LiCoPO4. Furthermore, the LiFePO4 coated LiCoPO4 cell exhibits an improved capacity retention compared to the original LiCoPO4 during cycling.