Effect of Cerium Chloride on the Self-Corrosion and Discharge Activity of Aluminum Anode in Alkaline Aluminum-air Batteries

Abstract

One of the key impediments to aluminum (Al) as an anode in alkaline Al-air batteries is self-corrosion, which limits the battery’s efficiency due to the capacity loss and lifespan reduction. Thus, it is vital to find an efficient electrolyte additive that reduces self-corrosion in Al anodes. In this study, the effect of adding 0.5 to 1.5 wt% of cerium chloride to 4 mol l−1 KOH electrolyte on the self-corrosion of pure Al anode was investigated using electrochemical experiments. The results show that the addition of cerium chloride to the electrolyte reduces self-corrosion of the Al anode with a negligible effect on the anode activity. Cerium chloride forms cerium hydroxide (Ce (OH)3) in the alkaline electrolyte, which is adsorbed on the Al surface. Therefore, the corrosion potential increased, and self-corrosion current density decreased. As the cerium chloride concentration increased, the Al anode efficiency increased from 43.8% to 76.1%, and the capacity density increased from 1294 to 2244 mAh g−1. Furthermore, increasing the immersion time of the Al anode in the electrolyte containing cerium chloride increased the self-corrosion resistance and provided the self-healing properties for the anode.