Overview

• The liquid sodium metal fuel cell uses sodium–air reactions across a ceramic electrolyte to generate electricity with a stack-level density exceeding 1,200 Wh/kg, roughly triple that of lithium-ion batteries.
• Lab-scale prototypes have been tested in both vertical and horizontal configurations under controlled humidity, confirming consistent power output and the formation of removable sodium hydroxide byproducts.
• Expelled sodium compounds naturally absorb CO₂ to form sodium carbonate or bicarbonate, offering a potential strategy for atmospheric carbon capture and ocean deacidification.
• MIT-incubated startup Propel Aero aims to develop a brick-sized, 1,000-watt-hour version within a year, targeting large drones as its initial commercial use case.
• Beyond electric aviation, the high energy density and zero-carbon emissions profile could extend to shipping, rail transport and heavy-duty trucking with a projected three-year path to production.