A Self-Healable Polyelectrolyte Binder for Highly Stabilized Sulfur, Silicon, and Silicon Oxides Electrodes

Large volume change, poor conductivity, and electrolyte soluble active materials intermediates have long been daunting challenges for sulfur, silicon, and silicon oxides electrode materials. A self-healable polyelectrolyte binder is exploited by crosslinking polydopamine, phytic acid and poly(acrylamide-co-2-(Dimethylamino)ethyl acrylate) in situ at room temperature through reconfigurable hydrogen bonds and ionic bonds. Therefore, the crosslinked binder network can readily recover its mechanical strength without extra stimulus, offering a reliable strategy for electrodes plagued by large volume change issue. Sulfur (S) and silicon (Si) electrodes prepared using the self-healable polyelectrolyte binder can effectively maintain its structure integrity after long-term cycling. In addition, the polar groups, especially negative-charged phosphate ions empower the polyelectrolyte binder as a more effective binder than commercial poly(vinylidene fluoride) in terms of restraining lithium polysulfides shuttling and accelerating lithium ion transportation, as evidenced by in situ UV-visible spectroscopy, density functional theory calculation and cyclic voltammetry. Consequently, high-active materials loading S cathode, Si and SiO-graphite anodes all achieve high area capacity and satisfying cycling stability by conveniently applying the advanced binder. This facile strategy for constructing multiuse binder illuminates versatile development in many energy storage systems.

Automated summary

This study addresses the challenges faced by sulfur, silicon, and silicon oxide electrode materials, such as large volume change, poor conductivity, and solubility of active material intermediates, by developing a self-healable polyelectrolyte binder. Experimental evidence and computational simulations demonstrate that the novel binder offers a reliable strategy for electrodes, with enhanced performance in restraining lithium polysulfide shuttling and accelerating lithium ion transportation.