Preparation of LiFePO4 rods, LiFePO4/graphene composite and their electrochemical performances
Rod-like LiFePO4 particles were prepared via solvothermal method using a mixed solution of isopropanol and deionised water as solvent with sucrose and nitrilotriacetic acid as additives. The effects of solvents and additives on the microstructure, chemical composition and morphology of the obtained products were investigated by powder X-ray diffraction, scanning electron microscopy and energy dispersive spectrometer. Results indicated that nitrilotriacetic acid made an important contribution to the rod-like morphology. The obtained LiFePO4 particles were further dispersed in graphene oxide sol to prepare the LiFePO4/graphene composite, followed by heat treating in Ar/H2 atmosphere. The electrochemical properties of LiFePO4 and LiFePO4/graphene composite as cathode in lithium ion cells were tested via galvanostatic charge/discharge cycling. Both LiFePO4 and LiFePO4/graphene composite demonstrated stable performance over 100 cycles. Compared with pure LiFePO4, the specific capacity was improved extensively in the LiFePO4/graphene composite.