2026 年 94 巻 5 号 p. 052010
Noncarbon-based air electrodes for metal–air batteries were investigated to enhance bifunctional activity for both the oxygen reduction reaction (ORR) and oxygen evolution reaction (OER), as well as to improve durability during repeated OER–ORR cycling in alkaline aqueous electrolytes. A bilayer structure composed of a gas diffusion layer (GDL) and catalyst layer (CL) was constructed using antimony-doped tin oxide (ATO) as a substitute for carbon typically employed in conventional air electrodes. Optimizing the polytetrafluoroethylene content within the ATO-based GDL maximized air permeance and enhanced ORR performance while preserving OER activity. An air electrode incorporating an ATO-based GDL and a CL composed of a mixture of La0.6Ca0.4CoO3 and ATO exhibited reversibility for both the ORR and OER. This noncarbon-based air electrode demonstrated superior stability under high anodic potentials during the OER compared with carbon-based electrodes, without inducing significant morphological or phase transformations. These findings demonstrate the noncarbon-based air electrode as a viable cathode candidate for secondary metal–air batteries, which require high reversibility and resistance to corrosion under high operating potentials.
