EFFECTS OF DIFFERENT CARBON SOURCES ON PROPERTIES OF LiFePO 4/ C BY A CARBOTHERMAL REDUCTION METHOD

The LiFePO 4/ C composite was prepared by carbothermal reduction method (CTR) with FePO 4 ⋅ 2 H 2 O , Li 2 CO 3 as starting materials, and acetylene black or polyethylene glycol (PEG; mean molecular weight of 10,000) as carbon sources. The structural and electrochemical properties were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmittance electron microscopy (TEM), and charge–discharge tests. The results showed that LiFePO 4/ C is olivine-type phase, and the addition of carbon reduced the LiFePO 4 grain size with uniform distribution. The carbon is dispersed between the grains, forming a good electronic contact. The synthesized LiFePO 4 composites showed excellent electrochemical performance with initial discharge capacity of 161, 142 and 96 mAh ⋅ g-1 at 0.1 C, 1 C and 5 C, respectively and displays a robust rate capacity and stable cycling life.