Synthesis of LiFePO4 Nanoparticles by Solvothermal Process Using Various Polyol Media and Their Electrochemical Properties

Olivine structured LiFePO4 samples were synthesized by solvothermal process using various polyol media of ethylene glycol (EG), diethylene glycol (DEG), triethylene glycol (TEG), and tetraethylene glycol (TTEG) without any heating as a post procedure. The X-ray diffraction patterns of the samples prepared in EG and DEG showed the crystalline peaks with well-fitted to the positions on the basis of an olivine type structure without any impurities. In order to determine the unit cell parameters, synchrotron powder XRD patterns were fitted with whole-pattern profile matching method using FULLPROF program. The obtained samples exhibited well dispersed nanoplate morphologies excepting for the sample prepared in EG. The samples prepared in EG, DEG, TEG, and TTEG showed the reversible capacity of 118, 167, 90, and 105 mAh/g at current density of 0.1 mA/cm2, respectively. Among them, the samples reacted in DEG and TTEG showed good performances at high rate of 16C with high capacities retention.