Effect of different binders on electrochemical properties of LiFePO4/C cathode material in lithium ion batteries

LiFePO4/C nano-composite has been successfully synthesized by solid-state reaction. The crystal structure and morphology of the LiFePO4/C are characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The results indicate that single-phase LiFePO4/C with olivine structure and suitable particle size was obtained. The electrochemical performance of the LiFePO4/C electrodes with poly(methyl methacrylate) (PMMA), poly(vinylidene fluoride) (PVDF) and poly(vinylidenefluoride-co-hexafluoropropylene) (PVDF-HFP) as binders are compared. Galvanostatic charge-discharge testing shows using PVDF-HFP binder has highest rate capability and cyclic property. The better rate performance and cycling stability of the LiFePO4 /C electrode containing PVDF-HFP binder is found to be due to the more free mobile Li+ ion providing form the higher amorphocity and lower glass transition temperature (Tg). Crown Copyright (C) 2013 Published by Elsevier B.V. All rights reserved.