Beyond Barrier Function: Exploring the Potential of Polymer Coatings for High-Performance Aluminum–Air Batteries

Aluminum–air batteries are known for their high energy density but are hindered by aluminum corrosion. This research delves into the utilization of polymer coatings through dip coating to enhance discharge longevity. Commercial aluminum electrodes are treated with poly(vinyl alcohol) (PVA), poly(vinylidene fluoride) (PVDF), and poly(tetrafluoroethylene) (PTFE), and their effects on surface hydrophobicity and discharge duration are assessed. A standardized 0.5 M KOH electrolyte and air-breathing cathode are utilized. Among the polymers tested, PTFE exhibits the most favorable outcome due to its superior hydrophobic properties. Aluminum electrodes coated with PTFE demonstrate a notable extension in discharge duration compared with uncoated or PVA/PVDF-coated electrodes. Under the conditions of 0.5 M KOH electrolyte concentration and a current density of 1 mA/cm2, uncoated electrodes exhibit a discharge duration of around 5 h. PTFE-coated electrodes achieve discharge durations surpassing 30 h, marking a severalfold enhancement. Furthermore, PTFE-coated electrodes sustain satisfactory performance even at a higher current density of 10 mA/cm2, underscoring their potential for practical use. Factors contributing to enhanced performance were comprehended through various characterization techniques.