Dual modulation of electrolyte inner solvent structure and anode interface for high performance alkaline Al-air battery

Abstract

In this work, we propose a Water-in-salt electrolyte based on concentrated ionic additive for Al-air batteries, aiming at inhibiting the unexpected severe hydrogen evolution self-corrosion. Computing calculations and experimental characterizations consistently confirm that the additive can significantly affect both the solvent structure and anode interface. A stronger H-bonding network is reconfigured and formed in the electrolyte, thus leading to a dramatic decrease in free water content and activity. Besides, the adsorption behavior of used additive molecules on Al anode surface plays an activating and stabilizing role, which is conducive to promoting the uniform dissolution of Al anode and improving the electrochemical performance. Owing to this dual modulation, the electrolyte system endows Al-air battery with extremely low self-corrosion rate (reduced by 89.6%) and remarkable discharge capacity of 2623 mAh/g.