Biodegradable hydrogels with tunable cross-linking structures regulate Al oxidation in Al–air batteries

Internet of Things (IoT) devices and small robots would benefit from higher-energy-density and disposable primary Al–air batteries, but corrosion and side reactions on the Al anode limit the widespread application of this chemistry. This paper studies how the physical and chemical characteristics of double-network hydrogel (DNH) electrolytes affect the anode oxidation, discharge morphology, and performance of Al–air batteries. The chemically crosslinked and physical–chemical crosslinked DNHs were made from biodegradable materials and showed enhanced corrosion inhibition compared to aqueous KOH solution, reducing the corrosion rate by 58% to 21 mmpy. An Al–air battery with a PVA-PAAM DNH extracted over 300 mAh cm −2 from Al at 10 mA cm −2 . Graphical abstract