Improving the performance of primary aluminum-air batteries through suppressing water activity by hydrogen bond-rich glycerol solvent additive

In this work, glycerol is introduced as a low-cost and eco-friendly electrolyte additive for primary aluminum-air (Al-air) battery. Glycerol molecules form hydrogen bonds (H-bonds) with water (H2O) molecules to reconstruct hydrogen bond network in the electrolyte, leading to a reduction in the H2O activity. Accordingly, the hydrogen evolution potential of electrolyte is expanded, the hydrogen evolution reaction (HER) and self-corrosion of Al anodes are suppressed. As a result, the capacity density, and energy density of Al-air battery are increased significantly in the presence of glycerol. With the glycerol content of 20% in 4 M NaOH electrolyte, the capacity density of Al-air battery exhibits a value of 2564 mAh g − 1, which is 2.3 times higher than in 4 M NaOH electrolyte.