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

LiFePO4/C electrodes using different structure of binders display different electrochemical performance. [Display omitted] •The electrochemical performance of the LiFePO4/C electrodes with PMMA, PVDF and PVDF-HFP as binders was compared.•The PVDF-HFP-based electrode had the highest rate capability and cyclic property.•The result can be attributed to the higher amorphocity and lower glass transition temperature. 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).