Synergistic inhibition effect of poly(ethylene glycol) and cetyltrimethylammonium bromide on corrosion of Zn and Zn-Ni alloys for alkaline batteries

The synergistic inhibition effect of poly(ethylene glycol)-400 (PEG-400) and cetyltrimethylammonium bromide (CTMAB) on the corrosion of Zn and Zn-Ni alloys in 8 mol/L KOH solution saturated with ZnO was observed by potentiodynamic anodic/cathodic polarization (PDP), and electrochemical impedance spectroscopy (EIS) measurements. The electrochemical studies confirmed that there was a synergism between PEG-400 and CTMAB on corrosion inhibition of Zn and its alloys. Corrosion inhibition efficiency of the mixed inhibitors, 250 mg/L CTMAB + 250 mg/L PEG-400, was found to be much higher than that of the single inhibitor, 500 mg/L PEG-400 or 500 mg/L CTMAB. Scanning electron microscopic (SEM) investigations before and after the corrosion inhibition process emphasize the synergistic effect of the mixed inhibitors. Accordingly, it was found that the addition of the investigated inhibitors to the alkaline solution enhanced the discharge and capacity of the alkaline battery anodes. The obtained electrochemical data exhibited a good correlation with the computational one.