Freeze-drying method for LiFePO4/C composite processing

Abstract

Based on its high capacity, stability, low toxicity and low cost of raw materials, phosphoolivine LiFePO4 became a material of great interest for Li-ion battery application. Synthesis of LiFePO4/C cathode material was performed by freeze-drying method using different organic acids as carbon source. Freeze-drying process consists of freezing of a precursor solution, elimination of solvent by sublimation (vacuum drying) and final calcinations of as-dried powder under slightly reductive atmosphere. The main advantage of this synthesis method is possibility of introducing a carbon source and mixing of reactants at atomic level which provides homogeneity of precursor solution. Synthesized materials were characterized by X-ray powder diffraction, scanning electron microscopy, particle size analyzer and galvanostatic charging/discharging.