Abstract
Zn-based sacrificial anodes (DSAs) in chloride-contaminated concrete often exhibit low utilization and limited sustained performance because the anode-matrix interface progressively degrades. Poor electrolyte access, passivation, and accumulation of Zn-based reaction products reduce ionic continuity and hinder sustained anodic dissolution. This study introduces a polyvinyl alcohol (PVA)-based hydrogel electrolyte (PHE) layer applied onto Zn-based anodes to enhance the stability of the anode-matrix interface. The PHE improves anode-electrolyte interaction and accommodates anodic products, while its measured ionic conductivity (∼ 2.94 mS/cm) confirms sufficient ion-transport capability. Electrochemical tests confirmed improved performance of PHE-modified anodes in mitigating steel corrosion in chloride-rich environments. Electrochemical impedance spectroscopy (EIS) showed reduced charge transfer resistance at the interface, while scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDS) analyses revealed the improved morphology of the anode-matrix interface and wider dispersion of Zn-based products. These results demonstrate that the PHE layers significantly enhance the electrochemical efficiency and improve sustained electrochemical performance of sacrificial anodes, offering a promising solution for corrosion protection in reinforced concrete.
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•A PVA-based hydrogel electrolyte was applied to regulate the Zn anode–matrix interface in DSAs.•PHE-modified anodes improved the CP performance in chloride-contaminated concrete.•The hydrogel layer enhanced anode-electrolyte interaction and retained electrolyte.•PHE facilitated dispersion of anodic byproducts and stabilized the evolving interface.•Electrochemical and microstructural analyses revealed improved interfacial transport and activity.