One-Pot Synthesis of a Copolymer Micelle Crosslinked Binder with Multiple Lithium-Ion Diffusion Pathways for Lithium-Sulfur Batteries.

Abstract

Fast lithium-ion diffusion is very important to obtain high capacity and excellent cycling stability of lithium-sulfur batteries. In this study, a copolymer micelle crosslinked binder (FNA) for lithium-sulfur batteries was successfully synthesized through a one-pot environmentally friendly approach. The micelles were used as crosslinkers and carriers for the electrolyte. The FNA binder provided multiple lithium-ion diffusion pathways to increase the lithium-ion diffusion, which reduced the polarization of the sulfur cathode during the cycling process. The lithium-ion diffusion pathways of the FNA were provided by the electrolyte hosted in the micelles, the polyethylene oxide and polypropylene oxide segments, and the carboxylate and sulfonate groups in the FNA. In addition, FNA possesses strong lithium polysulfides adsorption and high adhesion properties. Therefore, the electrode with the FNA binder presented a reversible capacity of 571 mAh g-1 with a capacity fade of 0.032 % after 1000 cycles at a cycling rate of 0.5 C, which is much higher than those of the polyvinylidene fluoride (PVDF) sulfur cathode.