Synthesis and Characterization of High tap-density LiFePO4 Cathode Material for Lithium Ion Batteries

Abstract
Lithium iron phosphate (LiFePO4) is a promising cathode material for lithium ion batteries because it has the advantages of environmental benignity, high safety, and low cost. Despite of these advantages, the main problem of LiFePO4 d is low tap density, which causes very low energy density. This work focuses on the synthesis of LiFePO4 powder with high tap density. A two-step process will be carried out to synthesize spherical and micro-size LiFePO4 particles.
In the first step, Fe(NO3), H3PO4 and NH3 were used as starting materials to prepare FePO4 via co-precipitation method. The result shows that different precipitation conditions, including residence time, pH of reaction, agitation power density, and reactant concentration affect the size and morphology of the FePO4 powder.
In the second step, the FePO4 particles were mixed with a stoichiometric amount of Li source and glucose as the carbon coating source. Olivine powder with tap density greater than 1.5 g/cc had been synthesized. The correlations among the sintering temperature, microstructures, tap density and the electrochemical performance have been studied in detail.