Synthesis And Electrochemical Performance Of Hiearchical Phosphate Nanomaterials

Lithium ion battery materials based on the olivine structure LiMPCU have recently been proposed as potential candidates for high energy and high rate applications because of their high security, environmental protection, cheap raw materials, high capacity and stable performance. However, their intrinsic low electronic conductivity and poor ionic transport property are the limiting factors to achieving high rate performance.Herein, we report the controlled fabrication of three-dimensional (3D) LiMPO4microspheres via facile and mild solvothermal routes to LiMPO4spheres with micro/nano-structure, which are highly desired for designing high performance lithium-ion batteries with high volumetric energy density and good rate capability because nanosized primary structures ensure high rate capability and micro-sized secondary structures guarantee a high tap density. Such3D architectures with unique shapes and excellent properties can be considered as good candidates as cathode material for the Lithium ion batteries.1. LiFePO4microspheres with three-dimensional (3D) hierarchical structures were synthesized by a facile solvothermal process for the first time. The LiFePO4microspheres are composed of numerous nanoparticles with the size of100nm. The effects of the volume ratio glycerol and water, amount of citric acid, and reaction time on the morphology of the LiMPO4products were investigated and the possible formation mechanism was proposed based on time-dependent experiments. The electrochemical properties of carbon-coated LiMPO4microstructures were investigated, which exhibit high discharge capacity, good cycling stability and rate capability.2. Novel3D hierarchical peach-like LiMnPO4microspheres have been for the first time synthesized by a facile solvothermal reaction.The morphology evolution, formation mechanism and the effects of reaction parameters on the formation of the sample were investigated in detailed. After carbon-coated, LiMnPO4microspheres exhibit excellent electrochemical properties as a promising cathode material.3. The a spindle-shaped LiMPO4(M=Fe, Mn) architectures were synthesized under hydrothermal conditions by using different surfactants and organic acids. The effects of amount of surfactant, reaction temperature and reaction time on the morphology of the LiMPO4products were investigated. The LiMPO4microstructures will be promising cathode materials.