Regulating Zn²⁺ flux and transport behavior with CF₃-functionalized UiO-66 modified separator for high-performance...

The increasing demand for more sustainable and safer energy storage systems has driven significant interest in finding alternatives to conventional lithium-ion batteries. Rechargeable aqueous zinc-ion batteries (AZIBs) have emerged as promising candidates due to their high theoretical capacity and the natural abundance of Zn. However, the performance of AZIBs is often limited by the instability of Zn anodes, leading to challenges such as dendrite formation, side reactions, and poor cycling stability. To address these issues, a novel modification strategy is proposed for glass fiber (GF) separators by incorporating trifluoromethyl-functionalized UiO-66 (CF₃-UiO-66 and (CF₃)₂-UiO-66) through a one-step hydrothermal synthesis. This modification significantly enhances the separator's ability to regulate Zn²⁺ flux, accelerates the de-solvation process, and effectively suppresses dendrite growth. The (CF₃)₂-UiO-66@GF separator demonstrates outstanding electrochemical performance, achieving stable cycling in Zn||Zn symmetric cells for over 2000 h at 2 mA cm^-2 and 1 mAh cm^-2, with an extended lifespan of more than 800 h at 5 mA cm^-2 and 2 mAh cm^-2. Full cells equipped with this separator exhibit superior rate performance and enhanced capacity retention, underscoring the potential of this separator engineering strategy for advancing the performance and practical application of AZIBs.