Promoting Non-Water-Induced Zn²⁺ Conduction During Reversible Zn²⁺ Solvation Processes Toward Sustainable Aqueous Zn...

Aqueous Zn metal batteries represent a promising grid-scale renewable energy storage technology, yet their performance has long been constrained by the interfacial issues of Zn anode materials. An ideal Zn anode/electrolyte interface should combine a water-poor environment with high Zn²⁺ conductivity. Herein, the non-water-induced Zn²⁺ conduction on the Zn surface during Zn²⁺ solvation/de-solvation processes is promoted to enable sustainable aqueous Zn metal batteries. Specifically, a sequential bilayer of polydopamine and Nafion on the Zn metal anode established hydrophilic-hydrophobic domains that promoted the reversible Zn²⁺ solvation processes. Simultaneously, this interfacial design created a water-poor environment on the near Zn surface, while achieving a Zn²⁺ conductivity of 23.4 mS cm^-1 and a record-high transference number of 0.95. Consequently, highly reversible Zn plating/stripping are both achieved, and 91.1% of the corrosion side-reaction is suppressed. Such a Zn anode demonstrated its success in a 102 mAh pouch cell with commercial MnO₂ cathode, which exhibited a capacity retention of 96.7% with a high Coulombic efficiency of 99.97% after 100 cycles at 1 C, outperforming the counterpart with commercial Zn anode (Capacity retention: 43.1%, CE: 99.12%).