Persulfate-based ionic liquid additives for corrosion inhibition and enhanced discharge performance of aluminum-air batteries

A multifunctional ionic liquid additive has been designed and synthesized for the aluminum-air battery. • Cation-dominated parallel adsorption enables effective corrosion protection with reversible desorption during discharge. • Vertically adsorbed anions deliver dual functions: filling adsorption gaps to reinforce corrosion inhibition and elevating the cathodic discharge voltage. Aluminum (Al)-air batteries have recently attracted considerable interest due to their high energy density, low cost, and the lightweight properties of Al. However, the self-corrosion of Al anodes hinders their commercial applications. This study aims to address these limitations by designing and synthesizing persulfate-based ionic liquid ([C 12 MIM] 2 [S 2 O 8 ]) as electrolyte additive. Results demonstrate that [C 12 MIM] 2 [S 2 O 8 ] additive significantly enhances corrosion resistance of the Al anodes. Consequently, the full battery exhibits appealing performance characteristics, including a superior energy density of 2796.9 Wh kg -1 at 20 mA cm -2 , a favorable operating voltage, and anode utilization of 70.3%. Characterization analyses, combined with theoretical calculations, further elucidate the mechanism of corrosion inhibition and observed performance enhancements. Therefore, this work offers a novel perspective on design of electrolyte additives, providing a potential approach to improve the performance and commercial viability of Al-air batteries.