A promising hybrid additive for enhancing the performance of alkaline aluminum-air batteries

Abstract

The low anode utilization and large capacity loss of aluminum due to the severe self-corrosion in alkaline electrolyte extremely restrict the practical applications of aluminum-air batteries. The vital challenge lies in the issue to slow down the self-corrosion rate without decreasing the discharge performance of aluminum anode. In this work, the application of zinc sulfate (ZnSO4) and sodium alginate (SA) as electrolyte additives to mitigate the corrosion of aluminum is investigated by hydrogen evolution test as well as the electrochemical measurements. The results show that zinc sulfate decreases the corrosion rate of aluminum mainly by restraining the cathodic reaction and exerts positive effect on the improvement of discharge performance for aluminum-air batteries. The hybrid ZnSO4/SA additive exhibits higher inhibition efficiency for the corrosion of aluminum than single ZnSO4 or SA, the adsorbed SA stabilizes zinc layer and improves the protective performance. Moreover, the cell voltage is prominently elevated while the discharge capacity increases from 162.46 to 267.41 mAh cm−2 with the dosage of 10 mM ZnSO4 and 1 g/L SA. A possible model is also proposed to elaborate the influence mechanism of the additive on the self-corrosion behavior and discharge performance of aluminum-air batteries.