Ultrahigh voltage and energy density aluminum‐air battery based on aqueous alkaline‐acid hybrid electrolyte

Thanks to the high theoretical capacity and energy density, abundant resource, low-cost, and environmental friendliness, aluminum-air battery (AAB) has attracted research interests driven by the promise for electricity generator. However, low operating voltage leads to low practical energy density, and restricting the applications of AAB. In this study, the concept of an ultrahigh voltage AAB based on aqueous alkaline-acid hybrid electrolyte is introduced and demonstrated. Meanwhile, the working mechanism is investigated. And the open-circuit voltage of the novel designed battery is 2.56 V, 29.9% higher than conventional alkaline AAB. Thanks to the fluid electrolyte, the decline in discharge voltage caused by the change in pH is overcome. And a high-energy density of 4591 mWh gAl−1 is achieved at a discharge voltage of around 2.08 V at 10 mA cm−2. These results provide a viable approach to improve the performance of Al-air battery.