Liquid Metal Battery Corporation is developing cheap, high-power, and high-capacity batteries to smooth out fluctuations on the power grid. This could help prevent blackouts, and allow the use of more intermittent sources of electricity such as solar and wind power.

The company’s headquarters, in the basement of an office building in Cambridge, Massachusetts, used to be occupied by a secretive military contractor. Now half of the space has the air of a startup—new furniture, bright walls, and a glass-enclosed conference room. The other half looks like a machine shop, where the researchers work to make the designs simple enough to be manufactured cheaply with standard equipment.