Sodium fuel cell could power an electric airplane

Hydrogen fuel cells, which power some electric cars, pack far more energy per weight than lithium-ion batteries. The devices also show promise for decarbonizing aviation, shipping, and trucking. But hydrogen fuel requires compression or cryogenic temperatures for storage.A new sodium-air fuel cell could be a more practical and sustainable power source (Joule 2025, DOI: 10.1016/j.joule.2025.101962). The fuel cell has an energy density of over 1,000 W h/kg, roughly four times that of typical electric vehicle batteries, which is the benchmark “that’s recognized as necessary to electrify aviation and other hard-to-decarbonize transport sectors,” says Yet-Ming Chiang, a materials scientist and battery specialist at the Massachusetts Institute of Technology who led the study. The device could, in theory, propel a single-aisle 50–100 passenger airplane—a size typically used for regional flights—for more than 320 km, Chiang says. And as it discharges, it produces sodium hydroxide (NaOH), which you could use to capture carbon dioxide or sell to the chemical industry, he says.Batteries and fuel cells produce electricity via electrochemical reactions. But while rechargeable batteries contain chemical components in a sealed package and produce electricity via reversible reactions, fuel cells rely on an external fuel source, so instead of recharging they need a refill of fuel.Chiang and his colleagues were inspired by metal-air batteries, in which redox reactions between a solid metal anode and oxygen from air at the cathode generate electricity. But these batteries aren’t rechargeable, and making the reactions reversible requires purifying the oxygen, which adds hefty, costly equipment. So the researchers