Extraordinary new energy storage technology based on cement

Insights — August 2023

Researchers at MIT appear to have made a breakthrough in the development of a large-scale energy storage technology using cement

The Proceedings of the National Academy of Sciences (an often-cited, peer reviewed scientific journal) reported that a team of researchers at the Massachusetts Institute of Technology has developed an innovative and scalable bulk energy storage technology.

Unlike a technology such as lithium-ion batteries, the key materials underpinning this technology are conventional Portland cement (the key ingredient in concrete, which is the most widely used manmade material on Earth) and carbon black (which is best known as an ingredient in rubber).

The researchers discovered that the combination of cement, water and carbon black creates the basis for a low-cost ‘supercapacitor’. A reaction during the cement curing process creates a branched conductive network within the hardened cement. When a standard electrolyte material is used, charged particles can accumulate on the carbon structure (resulting in energy storage). The researchers found that two electrodes prepared in this way and separated by an insulating layer, forms a powerful supercapacitor.

The researchers estimate that a block of this special material measuring 45 cubic metres in volume (equivalent to a roughly 3.5 metre cube) would have storage capacity of c.10 kilowatt hours (kWh) or roughly one third of the electricity the average household in the United States consumes over a 24-hour period.

While the researchers found a ratio of as little as 3% carbon black is required to achieve the conductive carbon network, they identified a trade-off between energy storage capacity and the structural strength of the material. In applications such as foundations, they estimate an ideal ratio of c.10% carbon black.

We find the prospect of concrete products being able to be tweaked to behave like batteries to be quite extraordinary. Especially because of the potential it creates to leverage a sunk cost (the existing concrete making industry), thereby creating the potential for very low-cost energy storage capacity.

While this technology is not likely to be commercialised in the short term, we believe case studies like this provide a taste of what the world’s innovators will come up with in response to our necessity (and an incentive price). While the estimates that the world needs c.240 terawatt hours (TWh) of energy storage capacity in order to achieve global net zero targets (relative to less than 1TWh today) seems almost unimaginably large, concrete’s extraordinary use in our modern world means that the potential scale of this technology is equally large.