Corrosion-resistant organic-inorganic hybrid interphase integrated with nitrile coordination enables highly stable...

Aqueous zinc metal batteries are promising for large-scale energy storage, but nonuniform Zn²⁺ transport, dendritic deposition, corrosion, hydrogen evolution, and insulating by-products undermine Zn reversibility. Here, a functionally stratified zinc oxalate/ polyacrylonitrile-zinc trifluoromethanesulfonate(PAN-Zn(OTf)₂) dual interphase is constructed on Zn by oxalic-acid-induced in situ conversion followed by solution coating(denoted as CNS@Zn). The outer PAN-Zn(OTf)₂ layer improves electrolyte wettability and ion-conduction capability, while nitrile-Zn²⁺ coordination modifies the local coordination environment of Zn²⁺ and facilitates more homogeneous interfacial Zn²⁺ transport. The in situ formed zinc oxalate inner interphase limits direct exposure of active Zn to the aqueous electrolyte, suppressing corrosion, hydrogen evolution, and parasitic by-product formation. This sequential regulation from ion delivery to interfacial deposition reduces the apparent interfacial activation energy from 76.36 to 41.85 kJ mol^-1 and promotes uniform, compact Zn deposition. Consequently, the CNS@Zn||NVO full cell retains approximately 140 mAh g^-1 after 1930 cycles at 5 A g^-1, while the CNS@Zn||NVO pouch cell maintains approximately 250 mAh g^-1 over 120 cycles at 1 A g^-1. This work establishes a hierarchical interface design coupling ion-transport regulation with corrosion protection for durable aqueous Zn metal anodes.