In‐Situ Integration of a Hydrophobic and Fast‐Zn2+‐Conductive Inorganic Interphase to Stabilize Zn Metal Anodes

The irreversible issues of Zn anode stemming from dendrite growth and water‐induced erosion have severely hindered the commercialization of rechargeable aqueous Zn batteries. Herein, a hydrophobic and fast‐Zn2+‐conductive zinc hexacyanoferrate (HB‐ZnHCF) interphase layer is in situ integrated on Zn by a rapid room‐temperature wet‐chemistry method to address these dilemmas. Different from currently proposed hydrophilic inorganic cases, the hydrophobic and compact HB‐ZnHCF interphase effectively prevents the access of water molecules to Zn surface, thus avoiding H2 evolution and Zn corrosion. Moreover, the HB‐ZnHCF with large internal ion channels, strong zincophilicity, and high Zn2+ transference number (0.86) permits fast Zn2+ transport and enables smooth Zn deposition. Remarkably, the resultant HB‐ZnHCF@Zn electrode delivers unprecedented reversibility with 99.88 % Coulombic efficiency over 3000 cycles, realizes long‐term cycling over 5800 h (>8 months, 1 mA cm−2) and 1000 h (10 mA cm−2), and assures the stable operation of full Zn battery with both coin‐ and pouch‐type configurations. In situ integration of a hydrophobic and fast‐Zn2+‐conductive inorganic interphase layer composed of zinc hexacyanoferrate (ZnHCF) on Zn by a room‐temperature wet‐chemistry method effectively addresses the irreversible issues facing Zn anodes involving dendrite growth and water erosion, while the hydrophilic and loose ZnHCF particles‐based interphase counterpart cannot efficiently prevent water erosion on Zn during long‐term cycling.