Masakazu Togo

Synthesis and Evaluation of Olivine Nanosheets from Layered Ammonium Iron Phosphate Monohydrate

The synthesis of novel microstructured LiFePO4 with advantageous nanosheets for Li ion conductivity was attempted. Using layered NH4FePO4•H2O as raw material, LiFePO4 nanosheet was synthesized by the hydrothermal process in LiCl solution. Prepared NH4FePO4•H2O was several tens micrometer sized sheet with about 200 nm in thickness. As Li ion resource, various LiCl solution like deionized water, ethanol, and ethylene glycol were prepared through subsequent hydrothermal process and the effect of a kind of solvents for LiCl solution on the microstructure of products treated by the hydrothermal process was investigated for LiFePO4 nanosheets synthesis. The products of LiFePO4 nanosheet were characterized by XRD, SEM, TEM, FT-IR and ICP. Regardless of a kind of solvents, LiFePO4 nanosheet was composed of arranged nano-blocks, although the size and morphology of nano-blocks was different in each solvent.

Nano and Submicron Olivine Synthesized by Hydrothermal Process

Development of cobalt free olivine material as a cathode for lithium ion battery was carried out. Especially, in this study, Mn substituted olivine was synthesized by hydrothermal process. With the reaction conditions, such as hydrothermal reaction temperature and times, the morphology and particle size were variable. Under the optimum synthetic condition, finer olivine particle was obtained by hydrothermal process. In addition, the effect of Mn addition on the microstructure of olivine was investigated.