Regulating Interface Engineering by Helmholtz Plane Reconstructed Achieves Highly Reversible Zinc Metal Anodes

Abstract The rampant dendrite growth and notorious parasitic reactions significantly compromise the stability of zinc anodes in aqueous zinc metal batteries, presenting substantial for their practical applications. Herein, this work proposes a synergistic strategy that reconstructs the Helmholtz plane to precisely regulate the interface chemistry between the anode and the electrolyte. Experimental investigations and theoretical calculations demonstrate that even a small amount of pyridine oxide (PNO) additive effectively alters the coordination environment and reorganizes the solvation sheath in the Outer Helmholtz Plane (OHP). Simultaneously, PNO molecules preferentially adsorbed on the anode surface, displacing active water from the Inner Helmholtz Plane (IHP). Through synergistic regulation in both the OHP and IHP, zinc ions achieve compact and dense deposition along the Zn (002) crystal plane, while parasitic reactions catalyzed by active water are effectively suppressed. Consequently, the symmetric cell incorporating the PNO additive demonstrates stable cycling performance, maintaining more than 2300 h at 1 mA cm⁻² and sustaining over 400 h even at a high depth of discharge of 85%. Furthermore, the Zn||AQ cell retains 80% of its capacity after 3000 cycles and exhibits outstanding cycling stability even under the high active material mass loading (22 mg cm⁻²) using the modified electrolyte.