Zero-emissions air travel may be one step closer after scientists at the Massachusetts Institute of Technology unveiled a new type of sodium fuel cell that could one day make electric-powered flight viable.
The sodium-air fuel cell – designed by a team led by Yet-Ming Chiang, professor of materials science and engineering at MIT – works by combining liquid sodium metal with oxygen drawn from the air to create a continuous reaction.
The device is "based on well-established electrochemical principles", said The Times. But "unlike conventional batteries, which must be recharged, it is designed to be refuelled, with its energy-rich material being replaced as it is consumed". In this way it is "more similar conceptually to hydrogen fuel cell systems", said MIT Technology Review.
With a Boeing 747 estimated to burn around 3,800 gallons of fuel per hour, or about one gallon every second, according to Simple Flying, the aviation industry has long sought a way to make air travel more sustainable (and cheaper).
In laboratory tests, the MIT sodium-air fuel cell prototype delivered more than five times as much energy per kilogram as the lithium-ion batteries currently used in cars.
But even so, sodium-air-powered flight is still some way off. The "next step", said MIT, is to continue research to "improve the cells' performance and energy density, and to start designing small-scale systems", with drones a potential option.
"We'd like to make something fly within the next year," Chiang said. | 
