Interfacial ionic and thermal regulation for highly reversible and ultra-reliable zinc-ion batteries

Abstract

Prevalent glass fiber separators in aqueous Zn-ion batteries (ZIBs) offer inadequate control over interfacial reactions, contributing to the rapid growth of Zn dendrites and aggravated parasitic reactions. Moreover, the stability of ZIBs under extreme operating conditions remains a critical yet often overlooked issue. Here, we present a novel silane-decorated glass fiber separator with engineered physical structures and surface chemistry, facilitating highly reversible and ultra-reliable ZIBs. Silane strengthens the separator, resists stress, and forms heat-insulating char layers under flame, ensuring reliability under extreme conditions. Silane networks also function as fillers that enhance pore uniformity for even Zn²⁺ flux. The amino groups in silane demonstrate comprehensive management of interfacial anions, cations, water transfer and reaction kinetics. This capability induces Zn²⁺ to concentrate at the interface, accelerates Zn²⁺ transfer, reduces deposition barriers, and obstructs water molecules and sulfate ions from participating in parasitic reactions. Consequently, dendrite-free Zn plating/stripping is achieved with 99.4% coulombic efficiency over 250 cycles, stable charge/discharge performance for 7000 hours, and remarkable cycling stability and flame resistance for Zn//V full batteries. This strategy demonstrates versatility across various separator materials and battery chemistry, offering a promising route to more reliable and higher-performing energy storage systems.