Abstract: A supercritical hydrothermal method was employed to prepare sub-micrometer LiFePO₄ particles with high purity and crystallinity. The structure and morphology of LiFePO₄ particles were characterized by X-ray diffraction and scanning electron microscope. The electrochemical tests were carried out to determine the reversible capacity, rate and cycling performance of the LiFePO₄ particles as cathode material for lithium ion battery. Experimental results show that solvent and calcining time have significant effects on purity, size and morphology of LiFePO₄ particles. Mixed solvent contained deionized water and ethanol is conducive to synthesize smaller and more uniform particles. The size of LiFePO₄ particles as-prepared is about 100-300 nm. The specific discharge capacities of the LiFePO₄ particles are 151.3 and 128.0 mA·h·g^-1 after first cycle at the rates of 0.1 and 1.0 C, respectively. It retains 95.0% of the initial capacity after 100 cycles at 1.0 C.

Key words: LiFePO₄, supercritical hydrothermal synthesis, lithium iron

摘要： A supercritical hydrothermal method was employed to prepare sub-micrometer LiFePO₄ particles with high purity and crystallinity. The structure and morphology of LiFePO₄ particles were characterized by X-ray diffraction and scanning electron microscope. The electrochemical tests were carried out to determine the reversible capacity, rate and cycling performance of the LiFePO₄ particles as cathode material for lithium ion battery. Experimental results show that solvent and calcining time have significant effects on purity, size and morphology of LiFePO₄ particles. Mixed solvent contained deionized water and ethanol is conducive to synthesize smaller and more uniform particles. The size of LiFePO₄ particles as-prepared is about 100-300 nm. The specific discharge capacities of the LiFePO₄ particles are 151.3 and 128.0 mA·h·g^-1 after first cycle at the rates of 0.1 and 1.0 C, respectively. It retains 95.0% of the initial capacity after 100 cycles at 1.0 C.

关键词: LiFePO₄, supercritical hydrothermal synthesis, lithium iron