Clean energy tends to come with drawbacks. Hydrogen has such low density that it’s hard to compress a useful amount of it into a container small enough to be practical; natural gas is more costly to transport and transfer than liquid fuels; batteries hold relatively little energy for their size and weight. But MIT chemistry professor Mircea Dincă has come up with a promising way to solve all these problems: sponges.
Dincă uses organic and metallic materials to form his sponges, which are so thoroughly riddled with microscopic chambers that in some cases, the surface area of just a gram would cover a football field if laid out flat. By mixing and matching these building blocks, he is able to control the size of the tiny chambers. Different configurations have different chemical and electrical properties.
Getting enough hydrogen on board a hydrogen-powered car requires either ultrahigh-compression tanks or cryogenic fuel tanks, but neither of these methods stores enough hydrogen to meet the U.S. Department of Energy’s target: a vehicle that can travel 300 miles without refueling. Dincă came up with a sponge capable of trapping twice as much hydrogen as ordinary tanks in a given volume. Adding a bit of heat or relieving some pressure coaxes the sponge to release the hydrogen when it’s needed.
Dincă’s sponges also make great sites for catalytic reactions, because the whole inner surface can be coated with a catalyst; the reaction can be controlled by altering the size of the sponge’s pores. He is developing variants of the sponges that could transform methane into a liquid fuel by efficiently catalyzing reactions that strip oxygen from air. He is also working on turning these sponges into materials for batteries and for organic photovoltaics.