A Solution–Precursor Synthesis of Carbon-Coated LiFePO[sub 4] for Li-Ion Cells

Carbon-coated, olivine-phase suitable for lithium-ion batteries have been prepared via a novel, one-step, low-cost synthesis route from aqueous precursor solutions of , and sucrose. Sucrose additions up to a mole fraction of 25% were found to suppress crystallization of the salts during the first stages of pyrolysis, thereby reducing elemental segregation and facilitating the formation of the olivine structure below 500°C in a single heating step. Sucrose also acted as a reducing agent and a source of carbon to form a conductive network in the active material during synthesis, leading to a higher capacity than materials in which sucrose was substituted with acetylene black. After additional treatment with sucrose at 700°C, the material achieved a capacity of at the rate and at in the voltage range vs Li.