Interface synergistic stabilization of zinc anodes via polyacrylic acid doped polyvinyl alcohol ultra-thin coating

Aqueous batteries have been considered as an alternative to lithium-ion batteries due to their advantages such as high energy density and high safety. Aqueous zinc ion batteries (ZIBs) have attracted particular attention due to the high capacity, low cost and low redox potential of zinc metal. However, zinc metal anodes suffer from problems such as dendrite growth, hydrogen evolution reaction (HER), and surface corrosion, which can lead to unfavorable effects, including reduced battery capacity and shorter cycle life. Herein, we constructed a PVA@PAA protective layer on the zinc anode surface by combining polyvinyl alcohol (PVA) with polyacrylic acid (PAA). This protective layer not only physically inhibits the growth of dendrites but also suppresses HER and surface corrosion via isolation of the electrolyte from the zinc anode. Furthermore, theoretical calculations indicate that PAA enhances the reactivity of PVA, increasing zinc ion transport rates and improving ionic conductivity. With the above synergistic effects, the symmetric batteries could achieve an ultra-long stable cycling of 2400 h at 3 mA·cm−2. Furthermore, this research lays the technical groundwork for the expanded applications of ZIBs on a larger scale.