Effect of Collard Greens Extract as an Electrolyte Additive on the Performance of Aluminum-Air Batteries

This work reports the use of collard greens extract as a potent inhibitor for self-corrosion of the aluminum electrode in an alkaline aluminum-air battery via galvanostatic discharge tests, weight loss measurements, and electrochemical measurements. Scanning electron microscopy (SEM), atomic force microscopy (AFM), and fourier transform infrared (FT-IR) spectroscopy were performed to explore the morphology of aluminum. The obtained results show that the utilization efficiency and capacity density of the battery were significantly enhanced by the presence of the extract. The inhibition efficiency attained the maximum values at 2.0 g l−1, about 89.61% and 87.90% from potentiodynamic polarization and electrochemical impedance spectroscopy measurements, respectively. Collard greens extract served as a cathodic inhibitor, and the adsorption mechanism of the extract adhered to the Freundlich adsorption isotherm. In particular, the physical absorption of the extract inhibitor on the aluminum surface was elucidated through nuclear magnetic resonance spectroscopy. Moreover, the phenolic compounds in the extract correspond to the corrosion inhibition effect on aluminum.