A Rigid-flexible binder for sulfurized polyacrylonitrile cathodes for rechargeable lithium batteries

Abstract

With the growing concern over increasing energy density, lithium–sulfur batteries have garnered significant interest from researchers. However, the volume expansion of the sulfur cathode, which leads to poor cycling stability at high loadings, poses a major challenge to their practical application. Traditional binders are highly susceptible to cracking and structural collapse as the coating thickness increases. Our study presents a dual-component composite binder (G2CEA) that harmoniously blends rigidity and flexibility, with each component serving a specific function. Guar gum (GG), the rigid component, envelops the SPAN interface and contributes to the formation of the CEI film, ensuring interface stability. Poly(2-Carboxyethyl acrylate) (PCEA), the flexible component, retains adhesion and ductility in the electrolyte, cushioning the volume changes of SPAN particles and maintaining the structural integrity of the electrode. This innovative design endows the G2CEA-based cathode with superior cycling stability (97.6% retention after 164 cycles at 0.1C) under high loadings (7.5 mg cm⁻²), offering a valuable perspective for the design of practical binders in the future.