Synergistic Reductive Electrolysis Mixture Additive-Based Dual-Cell Configuration: An Effective Approach for High-Performance Aqueous Aluminum–Air Battery

Abstract

Neutral aqueous electrolyte-based aluminum–air (Al–air) batteries have managed to gather significant attention because of their characteristic safety and cost effectiveness. However, the formation of the passivation layer [Al(OH)3] on the aluminum anode inhibits the long-term shelf life of the battery. Herein, a novel strategy to overturn the passivation by altering the aluminum/electrolyte interface is proposed. Incorporation of synergistic reductive electrolysis mixture additives (Tiron + NaNO3) can significantly reduce the passivation of the aluminum anode. The efficacy of the Tiron + NaNO3 synergistic mixture additive has been systematically examined using half-cell and full-cell with different concentrations of the additives in 0.5% NaCl. Furthermore, dual cell performance was investigated with optimum concentration (0.005 M Tiron + 0.005 M NaNO3) of the additive in 0.5% NaCl as the anolyte and different concentrations of H2SO4 as the catholyte. It is found that the resulting pumpless dual cell battery comprising neutral electrolyte with 0.005 M Tiron + 0.005 M NaNO3 mixture additive as the anolyte and 1 M H2SO4 as the catholyte demonstrated a remarkable cell potential of 1.14 V at a current density of 1 mA g–1, which is closer to the theoretical value. Morphological investigations using optical microscopy studies and X-ray photoelectron spectroscopic investigations also confirmed that the Tiron + NaNO3 additive is effective in preventing the discharge product on both anode and cathode surfaces and thus resulting in enhanced battery performance.