Corrosion inhibition of hybrid H₂QS/CaO additives for AA5052 alloy in alkaline solution

Abstract

BACKGROUND The parasitic H2 evolution reaction (HER) is the main problem preventing the development of the commercial Al‐air battery (AAB) in alkaline solution. The purpose of this study is to investigate a hybrid additive for alkaline AAB. The inhibition effect of the additives for HER is studied by hydrogen evolution test, electrochemical measurements, and scanning electron microscope (SEM). The stability of the battery and the anode utilization rate in alkaline solution are also investigated. RESULTS Results showed that the maximum inhibition efficiency was 86.52% for 0.08 g L−1 CaO + 0.5 mmol L−1 H2QS, and that the anode utilization rate increased to 90.7%. A spectrum analysis, including infrared, ultraviolet, and fluorescence, was conducted to analyze the corrosion inhibition mechanism. The chelation of the quinoline ring with Al3+ ions and the electrostatic interaction of sulfonic groups with Ca2+ ions produce a strong synergistic effect. CONCLUSION The hybrid H2QS/CaO additive has synergistic effects to help form a stable composite film that significantly retards the hydrogen evolution reaction of the Al alloy anode for the alkaline AAB. © 2022 Society of Chemical Industry (SCI).