In-situ chemical conversion film for stabilizing zinc metal anodes

Zinc metal anodes face several challenges, including the uncontrolled formation of dendrites, hydrogen evolution, and corrosion, which seriously hinder their application in practice. To address the above problems such as dendrite formation and corrosion, we present a simple and applicable immersion method that enables in situ formation of a zinc phytate (PAZ) coating on the surface of commercial Zn flakes via a substitution reaction. This protective coating mitigates corrosion of zinc flakes by the electrolyte, reduces the interfacial impedance, and accelerates the migration kinetics of zinc ions. Besides, this method can preferentially expose the (002) crystal plane with strong atomic bonding, which not only improves the corrosion resistance of the zinc flake, but can also guide the parallel deposition of zinc ions along the (002) crystal plane and reduce the formation of dendrites. Benefiting from the above advantages, the PAZ@Zn||Cu half-cell has shown over 900 cycles with average coulombic efficiency (CE) of 99.81% at 4 mA cm−2. Besides, the PAZ@Zn||PAZ@Zn symmetric cell operate stably for >1000 h at 5 mA cm−2 and >340 h at 10 mA cm−2. Furthermore, we demonstrated that this in situ chemical treatment enables the formation of a robust, well-bound protective coating. This method provides insights for advancing the commercialization of zinc anodes and other metal anodes.