A functional binder-sulfonated poly(ether ether ketone) for sulfur cathode of Li-S batteries

Sulfonated poly(ether ether ketone) (SPEEK) with strong electronegativity and adhesion ability of S/C compounds was prepared by a homogeneous reaction as the binder for the sulfur cathode of Li-S batteries compared to the conventional polyvinylidene fluoride (PVDF) binder. The binder and its applications to lithium sulfur batteries were characterized by proton nuclear magnetic resonance (H-1 NMR) spectroscopy, Fourier transformation infrared spectroscopy (FT-IR), thermogravimetry (TG), X-ray diffraction (XRD), scanning electron microscopy (SEM), electrochemical impedance spectroscopy (EIS), cyclic voltammogram (CV) and charge-discharge tests. The results show that this functional binder exhibits promising characteristics for lithium sulfur batteries with a capacity of 552.6 mA h g(-1) at a current density of 1600 mA g(-1) and 268.5 mA h g(-1) at 1000 mA g(-1) after 300 cycles.