Molecular Bridge Engineering at the Anode/Electrolyte Interface: Synergistic MPS/ZnO Hybrid Corrosion Inhibition for High-Utilization Alkaline Al-H2O Batteries

Abstract Aluminum-water (Al-H2O) batteries, enabling on-demand high-purity hydrogen production and simultaneous power output, hold great promise for hydrogen energy and electrochemical energy storage applications. However, severe self-corrosion of aluminum anode and parasitic hydrogen evolution reaction (HER) in highly alkaline electrolytes hinder their practical deployment. This work proposes a novel organic–inorganic hybrid corrosion inhibitor comprising sodium 3-mercapto-1-propanesulfonate (MPS) and zinc oxide (ZnO). Combined experimental and computational investigations demonstrate that a dense, robust adsorption–deposition composite protective layer is formed on the anode surface via a “molecular bridging” synergistic mechanism, delivering a corrosion inhibition efficiency of 72.9%. In alkaline Al-H2O full-cell tests, the battery achieves 77.5% anode utilization, and a specific capacity of 2309 mAh g–1 at 20 mA cm–2. This work offers valuable guidance for designing high-performance hybrid corrosion inhibitors for Al anodes.