Synthesis of 3D-hiearchical LiMPO4 (M = Fe, Mn) microstructures as cathode materials for lithium-ion batteries

LiMPO4 (Fe, Mn) microspheres with three-dimensional (3D) hierarchical structures were synthesized by a facile solvothermal process in a solution of glycerol and water with the addition of citric acid. The LiFePO4 microspheres are composed of numerous nanoparticles with the size of 100 nm while the peach-like LiMnPO4 microstructures consist of nanorods with the diameter of 50–60 nm and lengths of 200–300 nm. The effect of the volume ratio of glycerol and water, amount of citric acid, and reaction time on the morphology of the LiMPO4 products were investigated. The possible formation mechanisms were proposed based on time-dependent experiments. The electrochemical properties of carbon-coated LiMPO4 microstructures as the cathode materials were investigated, which exhibited high discharge capacity, good cycling stability and rate capability.