Hydrothermal synthesis of LiFePO₄ as a cathode material for lithium batteries

LiFePO₄ (space group: Pnma) was prepared by hydrothermal method at 170 °C. LiFePO₄ was prepared from precursor solutions consisting of FeSO₄ · 7H₂O, (NH₄)₂HPO₄, and three kinds of Li sources. LiCl, Li(CH₃COO), and LiOH · H₂O were used as Li sources. The pH of the precursor solution varied depending on Li source. The particle size, particle shape, and crystal texture of the obtained LiFePO₄ changed depending on pH. The electrochemical properties of the prepared LiFePO₄ were characterized as a cathode material for lithium batteries in an organic electrolyte at room temperature. The LiFePO₄ particle prepared from the precursor solution with Li(CH₃COO) was flake-like crystal (particle size: 1–2 μm) and had a preferred crystal orientation with a (020) texture. This LiFePO₄ exhibited a discharge capacity of 147 mA h g⁻¹, which was 85% of the theoretical capacity 170 mA h g⁻¹.