Anti-dendrite separator interlayer enabling staged zinc deposition for enhanced cycling stability of aqueous zinc batteries

Aqueous zinc ion batteries exhibit great prospects due to their low cost and high safety, while their lifespan is limited by severe dendritic growth problems. Herein, we develop an anti-dendrite hot-pressing separator interlayer through a mass-producible hot-pressing strategy, by spreading metal-organic framework (MOF) precursor on nonwoven matrix followed by a simple hot-pressing process. The in situ modification of MOF crystals on fiber surface processes abundant nitrogenous functional groups and high specific surface area (190.8 m2 g−1) with a strong attraction to Zn2+. These features contribute to a staged deposition behavior to promote uniform nucleation at high concentrations and two-dimensional grain growth at low concentrations. Consequently, Zn | |Zn symmetrical cells with hot-pressing separator interlayer demonstrate cycle lives of 3000 hours at 2 mA cm−2, 2 mAh cm−2. Moreover, Zn | |I2 pouch batteries with hot-pressing separator interlayer realizes 840 cycles lifespan with a capacity retention of 90.9% and a final discharge capacity of 110.6 mAh at 25 °C. Zinc deposition in aqueous zinc-ion batteries is influenced by separators. Here, authors introduce a mass-producible in situ MOF-modified separator interlayer to regulate Zn2+ concentration in two stages via nitrogenous groups, reducing zinc crystal nucleus radius and ensuring uniform zinc deposition.