An Ultrastable Rechargeable Zinc-Air Battery Using a Janus Superwetting Air Electrode

The rechargeable zinc-air batteries (ZABs) are promising energy storage devices, but their performance is limited by the air electrode, coming from the contradictory wettability requirements of the air electrode at charging and discharging. Herein, to improve the mass transport and adapt to its different requirements when charging and discharging the ZABs, a Janus air electrode was fabricated with a void-rich, superaerophobic oxygen evolution reaction catalytic layer and a dense superhydrophobic oxygen reduction reaction catalytic layer. The ZAB using the Janus air electrode exhibits a low voltage gap of 0.78 V for charging and discharging at 10 mA cm^-2, and it can stably work for more than 1 month (1100 cycles) with the decay of only about 10%. Wettability analyses revealed that the Janus superwetting structure provides good electrolyte contact, improves the mass transfer of O₂, and prevents electrolyte leakage and flooding, leading to the high performance. These results suggest the advantage of the Janus electrode in reversible energy-converting devices.