Effects of l-Cysteine Inhibitor on the Electrochemical Properties of an Aluminum Alloy Anode Used for an Aluminum-Air Battery

Serious self-corrosion and passivation film of Al-air battery reduces the actual energy density and limits its commercial application. The corrosion inhibition effect of l-cysteine on low-cost Al anode alloy and Al-air battery was studied using hydrogen evolution and electrochemical tests. The results show that l-cysteine can significantly reduce the corrosion current density of the Al electrode in 4 M KOH and improve the activity of the Al electrode. The optimum amount of inhibitor (0.5 M) improved the performance of the Al battery. The anode utilization efficiency reached 82.73%, and the battery life was prolonged by nearly three times. The cell capacity, energy, and maximum power density increased from 1990.67 mAh·g⁻¹, 1672.16 Wh·kg⁻¹, and 34.62 mW·cm⁻² in the system without inhibitor to 2465.33 mAh·g⁻¹, 2144.84 Wh·kg⁻¹, and 64.4 mW·cm⁻² in the system with 0.5 M l-cysteine. The researchers also used X-ray photoelectron spectroscopy (XPS) and other techniques combined with quantum chemistry calculation to obtain that ─COOH, ─NH₂, ─SH in l-cysteine form physical adsorption films on Al surface, which improves the corrosion resistance of Al alloy anode.