Utilizing an electrolyte additive to modulate interfaces and enhance anode discharge performance in aqueous magnesium–air batteries

Abstract

Aqueous Mg–air batteries possess tremendous potential for future energy storage applications owing to their inherent advantages in terms of safety and cost-effectiveness. Nevertheless, the practical implementation of this battery technology is impeded by uncontrolled self-corrosion at the anode and significant polarization caused by the accumulation of discharge byproducts. This investigation employed glycerol (Gly) as a novel electrolyte additive in aqueous Mg–air batteries, offering a dual solution to these challenges. The findings elucidated that an appropriate quantity of Gly effectively mitigates self-corrosion and polarization by facilitating the formation of an electrostatic shielding layer, a water-deficient electric double layer (EDL), as well as reconstructing the solvation sheath. By incorporating 3 v/v% Gly, the anode efficiency of the AZ31 anode witnessed a notable increase from 46.22% to 65.12% at a current density of 20 mA cm⁻². Moreover, the discharge voltage experienced an elevation from 1.10 V to 1.25 V, while achieving a high specific capacity of up to 1459.85 mA h g⁻¹. This study endeavors to provide a straightforward and feasible approach for developing high-performance and cost-effective aqueous Mg–air batteries.