Carbon-coated LiFePO4 synthesized by a simple solvothermal method

Abstract

A LiFePO₄/C composite was directly synthesized via a simple solvothermal method. Ferric nitrate nonahydrate, Fe(NO₃)₃·9H₂O, was selected as a low cost iron source in the ethanol process and glucose as the carbon source. Through SEM images, it was found that the concentration of the glucose solution has an important influence on the morphology of particles. The samples were characterized by Raman spectroscopy and TEM measurements, showing the formation of graphitic carbon, which is desirable for its contribution to the electronic conductivity. XPS analysis verified that Fe³⁺ was almost completely reduced to Fe²⁺. CV (cyclic voltammetry), EIS (electrochemical impendence spectroscopy), and galvanostatic charge/discharge tests were conducted to further study the electrochemical properties of the LiFePO₄/C composite. The results reveal that the LiFePO₄/C composite with a rodlike shape has the highest specific capacity of 147 mA h g⁻¹ at 0.1C, and the capacity retention remains 100% after 50 cycles.