LiFePO4 Mesocrystals for Lithium-Ion Batteries

Olivine LiFePO4 is considered one of the most promising cathode materials for Li-ion batteries. A simple one-step, template-free, low-temperature solvothermal method is developed for the synthesis of urchinlike hierarchical mesocrystals of pristine LiFePO4 as well as carbon-coated LiFePO4 composites. Each urchinlike mesocrystal consists of LiFePO4 sheets self-assembled via a dipolar field in spheres during a solvothermal process under the influence of Cl- anions. The obtained primary sheets of LiFePO4 are single crystalline in nature and can be coated in situ with an amorphous nitrogen-doped carbonaceous layer several nanometers in thickness. To increase the conductivity of the carbon coating, the materials are subjected to further temperature treatment (700 degrees C) under an inert atmosphere. The lithium storage performance of the pure LiFePO4 is compared with that of its carbon-coated counterparts.