After water, concrete is the most-used material in the world. And now, researchers have given this ubiquitous building material super powers. A Massachusetts Institute of Technology team has found a way to make a type of concrete that can store and release electricity.

This means that the concrete walls and sidewalks around us could double as giant batteries, powering lights and devices. About 5 cubic meters of the electron-conducting concrete—the volume of a typical basement wall—can hold enough energy to meet the daily needs of an average American household. The MIT researchers presented their advance in Proceedings of the National Academy of Sciences.

Buildings use over a third of the world’s energy and account for 40 percent of carbon emissions, according to the International Energy Agency. The concrete used to make these buildings is responsible for a big chunk of carbon emissions. That’s because making cement, the key ingredient of concrete, requires energy-intensive heat and the chemical reactions involved also release carbon dioxide.

Making construction materials do double-duty as energy-storing or carbon-capturing materials could help make future infrastructure more sustainable. Buildings could then store energy from solar panels directly in walls, instead of using batteries that rely on scarce materials that are environmentally harmful to mine and process. Researchers have in the past filled bricks with conductive materials, and have added carbon fibers and metal meshes to concrete blocks, to make them store energy.

The MIT team in 2023 made an energy-storing concrete by combining cement and water with ultra-fine carbon black particles and electrolytes. Meeting the average daily needs of a home required around 45 cubic meters of that concrete, roughly the amount used in a typical basement.

The new concrete formulation holds 10 times as much power. The researchers were able to achieve that by changing the electrolyte and manufacturing process. They tried several electrolytes, and found that the best performance came from organic electrolytes that combined ammonium salts, found in disinfectants and other products, with acetonitrile, a liquid often used in industry.

A cubic meter of this concrete—about the size of a refrigerator—can store over 2 kilowatt-hours of energy, about enough to power an actual refrigerator for a day.

They also changed how electrolytes were added to the concrete. Instead of soaking concrete in the liquid electrolytes, they mixed electrolytes into the water that is mixed with cement to make concrete. This allowed for thicker, more powerful electrodes, which increased energy-storing capacity.

“What excites us most is that we’ve taken a material as ancient as concrete and shown that it can do something entirely new,” said James Weaver, a co-author on the paper, in a press release. “By combining modern nanoscience with an ancient building block of civilization, we’re opening a door to infrastructure that doesn’t just support our lives, it powers them.”

Source: Damian Stefaniuk et al. High energy density carbon–cement supercapacitors for architectural energy storage. PNAS, 2025.