Effective zinc anode protection from in-situ ZIF-8 on electrospun electrolyte membrane for zinc-ion batteries

In this study, a one-step in-situ synthesized zeolitic imidazolate framework-8 embedded polyurethane/polyacrylonitrile electrospun membrane was developed for zinc-ion batteries. ZIF-8 was formed through a one-step reaction between zinc salt precursors inside PU/PAN fibers and an imidazole solution. Density Functional Theory calculations were employed to clarify the synthesis mechanism, revealing that zinc acetate precursor requires the lowest binding energy for ZIF-8 formation. Experimentally, the morphology and size of ZIF-8 obtained from different zinc salts and reaction times were systematically examined. ZIF-8 derived from various precursors exhibited distinct surface characteristics on the fibers. Electrochemical analysis showed that the ZIF-8@PU/PAN membrane synthesized using zinc sulphate achieved an ionic conductivity of 3.80 × 10 −3 S cm −1 and remained stable for 2000 h of zinc plating/stripping, effectively protecting the zinc anode. Post-cycling morphology confirmed the presence of uniform zinc flakes on the anode. A full cell equipped with a vanadium-based cathode delivered a capacity of 345 mAh g −1 at 0.2 A g −1 . Furthermore, in-operando X-ray absorption spectroscopy verified the change in the oxidation state of the cathode upon Zn 2+ intercalation. This study provides a straightforward fabrication strategy and mechanistic insight into ZIF-8@PU/PAN membranes for advanced zinc-ion batteries.