Hydrothermal Synthesis of Carbon-Coated LiFePO[sub 4] and Its Application to Lithium Polymer Battery

A carbon-coated platelike particle (space group: ) was prepared by employing a hydrothermal method at . The obtained particle had a preferred crystal orientation with a (020) texture, which was revealed by transmission electron microscopy and electron diffraction. After the hydrothermal treatment, further heat-treatments at high temperatures were carried out to increase the electrical conductivity of the carbon layer, and the conductivity was considerably improved by heat-treatment at temperatures higher than . The obtained particle exhibited a high-rate charge–discharge capability in a liquid electrolyte of /ethylene carbonate (1:1 volume ratio). The discharge capacity of the particle was more than at a discharge rate of . Furthermore, an all-solid-state cell comprising Li/polymer electrolyte/ was fabricated using a block copolymer electrolyte consisting of polyethylene oxide and polystyrene, and the charge–discharge performance of the cell was examined at . The all-solid-state cell exhibited a discharge capacity of at a rate of even at around room temperature.