Synthesis of LiFePO4/C composite electrode with enhanced electrochemical performance

LiFePO4/C composite was synthesized by high temperature solid-state reaction using iron(II) oxalate, ammonium di-hydrogen phosphate and lithium carbonate with a kind of carbohydrate dissolved in the dispersant(ethanol) as carbon sources added to the synthetic precursor. The samples were characterized by X-ray diffraction (XRD), scanning electron microscopy observations (SEM), charge/discharge test, cyclic voltammetry(CV) and carbon analysis. The results show that the synthesis of LiFePO4/C has ordered olivine structure. The carbon has two advantages: optimizing particle size of LiFePO4 and increasing the electronic conductivity and high Li+ diffusivity. The cathode material can demonstrate a charge/discharge flat voltage of 3.4 V (vs Li+/Li). Especially the active material with 15% and 20% carbohydrate added according to the final product of lithium iron phosphate shows very good electrochemical performance delivering about initial 150.2 mA (.) h (.) g(-1) and 162.0 mA (.) h (.) g(-1) specific capacity respectively at 0.1 C rate and the carbon contents in the final production are only 5.17% and 5.29%, respectively.