An enhanced-performance Al-air battery optimizing the alkaline electrolyte with a strong Lewis acid ZnCl2

Abstract

Al-air batteries are regarded as the potential energy conversion systems due to the ultra-high theoretical specific capacity of 2980 mAh/g and specific energy of 8100 mWh/g for Al anodes. However, the anodic self-corrosion has severely limited the energy efficiency, which induces a great challenge to the commercial penetration of Al-air batteries. Here, we present an alkaline electrolyte optimization with a single inorganic Zn-compound, where a strong Lewis acid ZnCl2 has the best modification effect for Al-air battery compared with ZnO and ZnCO3. The results demonstrate that the inhibition efficiency of Al anode is up to 83.03% under the adsorption of strong Lewis acid groups on the Zn protective film. The high specific capacity of 2322.91 mAh/g and specific energy of 2457.02 mWh/g for Al-air battery are obtained at the galvanostatic condition of 20 mA/cm2, and the anode efficiency is enhanced to 77.95% after ZnCl2 optimization. Moreover, the optimization mechanism is revealed, which provides a technical basis for the application of the enhanced-performance Al-air batteries in the fields of energy conversion and power supply.