Tailoring Molecular Competitive Adsorption for Stable Ah-Level Aqueous Zinc Metal Batteries

The water-dominated inner Helmholtz plane (IHP) at the electrode/electrolyte interface is a critical factor responsible for notorious parasitic reactions and Zn dendrite growth, which severely limit the development of aqueous zinc-metal batteries (AZMBs). In this work, we report a universal competitive adsorption strategy to reconstruct the interfacial molecular distribution and induce orderly Zn²⁺ deposition behavior by introducing DL-malic acid additive (denoted as DL). Specifically, the DL molecules preferentially adsorb on the Zn anode surface, forming a water-shielding IHP layer that effectively excludes water molecules. The zincophilic groups within DL provide abundant active sites and homogenize Zn²⁺ flux, achieving uniform Zn²⁺ deposition. Moreover, the original hydrogen-bond network is reset, thereby efficiently suppressing active water-induced parasitic reactions. As a result, symmetric cells with DL additive exhibit remarkable cycling stability over 8600 cycles at 5 mA cm^-2 and 1 mAh cm^-2, while Zn||Cu asymmetric cells achieve a coulombic efficiency of 99.9% over 3600 cycles. The advanced Zn||I₂ full cell delivers stable operation for 4000 cycles with 82.7% capacity retention at 1 A g^-1. Moreover, the Zn||I₂ pouch cell with limited N/P (1.82) reserves 78.2% capacity after 860 cycles. Surprisingly, an Ah-level Zn||I₂ pouch cell maintains marvel stability and reversibility over 220 cycles.