One of the biggest challenges facing the widespread adoption of renewable energy sources such as solar and wind power is storage.
Energy must be available when the wind is not blowing or when the sun goes down.
Researchers at the Massachusetts Institute of Technology (MIT) have developed cement-based supercapacitors capable of storing renewable energy.
This technology could turn homes into batteries and even charge vehicles while they are driving.
They specifically created a supercapacitor that could transform buildings into energy storage systems. Their findings were published in the journal PNAS.
The team combined two of the most abundant materials on Earth: cement and carbon black. When mixed with water, the material becomes a supercapacitor thanks to the electrical conductivity of the carbon black. As water reacts with the cement, it forms a network of tiny channels through which the carbon black migrates, creating thread like structures with fractal shapes. This process generates a very large contact surface between the carbon black and the cement. The material is then soaked in a standard electrolyte, such as potassium chloride. By connecting two plates of this material separated by a membrane, the researchers are able to create a functional supercapacitor.
According to the researchers, the energy density of their supercapacitor reaches about 300 watt hours per cubic meter. That is enough to power a light bulb for a day, but not much more. However, if around 45 cubic meters of this material were integrated into a building’s foundations, a home could store roughly 10 kilowatt hours of energy. That would be enough to cover the daily electricity needs of many households.
So far, the researchers have produced small button cell sized prototypes measuring about one centimeter in diameter and one millimeter thick, capable of delivering one volt. Their next goal is to develop a larger 12 volt version and eventually scale the technology up to structures containing as much as 45 cubic meters of material.
Beyond powering buildings, the team suggests that this technology could also be embedded into roads. In the future, it could make it possible to charge electric vehicles wirelessly as they drive, turning infrastructure itself into an active part of the energy system. Combined with renewable energy sources, such innovations could significantly reshape how electricity is stored and distributed.