Hydrothermal synthesis of lithium iron phosphate cathodes

Hydrothermal methods have been successfully applied to the synthesis of lithium iron phosphates. Li3Fe2(PO4)3 was synthesized by heating at 700°C LiFePO4(OH), formed hydrothermally in an oxidizing environment. Crystalline LiFePO4 was formed in a direct hydrothermal reaction in just a few hours, and no impurities were detected. This result leads to the possibility of an easy scale-up to a commercial process. The samples were characterized by X-ray diffraction, thermogravimetric analysis and scanning electron microscopy. Both phosphates were tested as the cathode in lithium batteries and showed results comparable to those formed by conventional high-temperature synthesis.