Crosslinked ion-conducting hybrid coating layers for robust artificial solid-electrolyte interphase towards high-performance silicon anodes

Abstract

High-capacity silicon (Si)-based anodes have been recognized as particularly promising candidates for high-energy-density lithium-ion batteries (LIBs). Rational design and tailoring of an artificial interface for Si anodes can effectively mitigate volume expansion, suppress detrimental side reactions, and enhance lithium-ion (Li⁺) diffusion kinetics—three critical factors widely acknowledged as fundamental prerequisites for enabling long-term cycling stability and fast-charging capabilities. Therefore, we introduced an organic/inorganic composite interface design strategy combining high elasticity and ion-conductive properties. Lithium metasilicate (LMS) not only functions as an effective protective layer and Li⁺ conductor but also inhibits lithium hexafluorophosphate (LiPF₆) hydrolysis to suppress the generation of corrosive hydrofluoric acid (HF). When integrated with carboxyl-rich polyacrylic acid (PAA), the nanocomposite coating layer demonstrates high elasticity to accommodate volume expansion, establishes continuous Li⁺ diffusion pathways, and promotes the formation of a robust lithium fluoride (LiF)-rich artificial solid-electrolyte interphase (SEI). Consequently, the as-developed Si@PL-10 electrode demonstrates significantly enhanced cycling performance (2297 mAh g⁻¹ after 200 cycles at 1 A g⁻¹) and high-rate capability (1854 mAh g⁻¹ at 6 A g⁻¹). This work provides valuable insights for designing scalable multifunctional coatings for high-performance Si anodes.