Modification on water electrochemical environment for durable Al-Air Battery: Achieved by a Low-Cost sucrose additive

Abstract

Low-cost and high-energy–density Al-air batteries have great application potential for energy conversion applications. However, their commercialization process has been challenged by severe self-corrosion of Al anode. Herein, a low-cost sucrose-modified electrolyte is utilized to inhibit the corrosion of Al anode for durable Al-air batteries. The sucrose molecules in KOH aqueous electrolyte can modulate the electrochemical environment of the water molecules in the electrolyte and decrease the number of active H₂O molecules, thus suppressing the self-corrosion reaction of Al anode effectively. In the Al-air full battery, the specific capacity of Al anode is 2330 mAh g⁻¹ in 4 M KOH + 2 M sucrose electrolyte much higher than 356 mAh g⁻¹ of pristine 4 M KOH electrolyte. Moreover, in the intermittent discharge experiments that simulate the practical applications, the discharge time of 1 g Al was also extended from 6 h into 22 h, showing great practical application prospects. This work provides a detailed reference for improving the electrolyte of Al-air batteries from the direction of reducing water activity.