Scientists Are Turning Concrete Into Energy Storage — Could Buildings Power Themselves?

Concrete is so ordinary that we barely notice it. It is under our feet, inside our homes, holding up bridges and forming the skeletons of cities.

Now imagine that all of that material could do something else while it was sitting there.

Imagine a house whose walls or foundation store electricity from rooftop solar panels during the day and release it after sunset. Or a parking structure that is not simply a mass of concrete, but part of the site's energy-storage system.

That is the idea behind a material being developed by researchers at MIT: electron-conducting carbon concrete, usually shortened to ec³.

Calling it a “concrete battery” makes for a good headline, although technically it is closer to a supercapacitor than a conventional lithium-ion battery. That distinction matters. What makes the research interesting is not that somebody poured a battery into a wall. It is that researchers are trying to make one of the world's most common structural materials store electrical energy without giving up its original job.

And the technology has improved considerably since its first widely reported demonstrations.

Concrete is everywhere. Energy storage isn't.

Solar and wind power have an obvious problem: they do not necessarily produce electricity at the moment we need it.

A solar roof may generate plenty of power at midday and almost nothing during the evening peak. Wind output can change with the weather. Energy storage helps bridge that gap, which is why batteries are becoming increasingly important in homes and electricity grids.

But large-scale storage requires enormous quantities of material.

That makes researchers interested in materials that are inexpensive, abundant and already used at huge scale. Concrete is an obvious candidate — if it can be given a second function.

MIT's approach combines cementitious material with extremely fine carbon black. Carbon black is a conductive form of carbon already produced at industrial scale for uses ranging from tyres to pigments.

Inside the cement, the carbon particles form a connected conductive network. Add an electrolyte and the material can behave as an electrode capable of storing charge.

The clever part is that the network forms throughout the material rather than relying on a conventional metal conductor running through it.

In other words, the concrete itself becomes part of the electrical device.

It isn't really a giant lithium battery

The word “battery” is useful shorthand, but ec³ stores energy as a supercapacitor.

A battery and a supercapacitor both store electrical energy, but they do it differently. Batteries generally rely heavily on chemical reactions and are designed to hold substantial energy for extended periods. Supercapacitors store charge in a way that allows very rapid charging and discharging and can typically survive a large number of cycles.

The trade-off is energy density. Conventional batteries can generally pack much more energy into a smaller volume.

That sounds like a serious disadvantage until you remember what concrete is used for.

Nobody wants a smartphone made from five cubic metres of cement. A building, however, already contains enormous volumes of concrete. If part of that existing structural mass can also store energy, low energy density becomes less absurd than it first appears.

The building provides the space almost for free because the material had another reason to be there in the first place.

That is the central idea behind multifunctional construction materials: instead of adding another separate system to a building, make a material already required by the structure perform additional jobs.

The latest version stores far more energy

The original MIT work attracted attention in 2023, when researchers demonstrated that cement, water and carbon black could be combined into an energy-storing supercapacitor.

The limitation was scale. Early estimates suggested that storing roughly a household's daily energy demand would require around 45 cubic metres of the material — roughly the volume of concrete that might be found in a residential basement.

By 2025, the team reported a major improvement.

Research published in the Proceedings of the National Academy of Sciences described optimized electrolytes, better understanding of the carbon network and improved manufacturing methods. The researchers reported roughly a tenfold increase in energy density compared with their previous designs.

MIT said the volume required for the same household-scale example could fall from about 45 cubic metres to around 5 cubic metres — closer to the volume of a basement wall rather than an entire basement's worth of concrete.

That does not mean you can order an energy-storing foundation for your house tomorrow. It does show why the research is attracting attention: an order-of-magnitude improvement changes the kinds of applications worth considering.

Researchers have already built working prototypes

This is more than a theoretical material calculation.

The research team demonstrated a 12-volt ec³ supercapacitor module capable of powering small electronics, including a computer fan and a device through USB. They also created a load-bearing arch incorporating the energy-storage material.

That arch is particularly interesting because it illustrates the real ambition of the project.

The goal is not to hide a conventional battery inside a block of concrete. The structural component itself is intended to become part of the energy-storage system.

The researchers have also explored whether electrical behaviour in the material could provide information about structural loading, potentially opening another function: monitoring the health of the structure itself.

A future piece of infrastructure could therefore theoretically support weight, store energy and help report changes in its mechanical condition.

That is a very different idea of what “concrete” can be.

Why carbon black matters

At first glance, cement and electricity seem like an unlikely combination.

Carbon black changes the equation.

When tiny carbon particles are dispersed through the cement mixture, they can assemble into branching, connected structures at microscopic and nanoscopic scales. The resulting network provides pathways for electrical conduction.

Researchers have used advanced three-dimensional imaging to study how these networks form and how they interact with electrolytes inside the material.

That matters because simply dumping more conductive carbon into concrete is not necessarily the answer. Construction materials still have to satisfy mechanical requirements. The challenge is finding a formulation that delivers useful electrical performance without destroying the qualities that made concrete useful in the first place.

It is materials science, electrical engineering and civil engineering meeting in the same bucket.

Could a house really store its own solar energy?

Potentially — but there is a large gap between “physically possible” and “commercially practical.”

The concept is attractive for solar-powered buildings. During sunny periods, excess electricity could charge structural supercapacitors. The stored energy could then be released when solar production falls.

In an off-grid building, storage integrated into the foundation or walls might reduce the amount of separate battery hardware required.

There are also potential advantages to supercapacitor-style storage. Rapid charging and discharging can be useful, and supercapacitors are generally associated with long cycle life.

But a real house has requirements that a laboratory prototype does not.

Engineers would need to know how the system behaves over decades. Construction crews would need reliable ways to manufacture and connect large sections. Electrical systems would require insulation, monitoring and safety controls. Building codes would have to account for the new technology.

Most importantly, the economics would have to make sense compared with simply installing ordinary batteries.

So the sensible answer is: yes, a building made partly from energy-storing concrete is technically plausible. No, it is not yet a normal construction product.

Roads and parking spaces are another possibility

Buildings are only one potential application.

MIT researchers have discussed roads and parking areas as possible uses for ec³ technology, including concepts related to electric-vehicle charging.

The appeal is easy to understand. Transportation infrastructure contains huge quantities of concrete and occupies enormous surface areas.

A parking area could potentially store renewable electricity generated nearby. More ambitious concepts imagine infrastructure participating directly in vehicle charging.

But this is where futuristic headlines can run ahead of engineering reality.

A road is a brutal environment. It experiences weather, water, temperature cycles, heavy loads, cracking, salt and constant mechanical wear. An energy-storage road has to survive all of those conditions while remaining safe and economically competitive.

A laboratory sample powering an LED or fan is therefore not evidence that highways will become giant chargers next year.

It is evidence that the underlying material can work — which is the first step, not the last one.

What about lithium, cobalt and nickel?

One reason alternative energy-storage technologies attract attention is the material supply chain behind conventional batteries.

Lithium-ion batteries are extraordinarily useful, but their production depends on mining and processing specific raw materials. Demand for batteries from electric vehicles, electronics and grid storage has made questions about cost, sourcing and environmental impact increasingly important.

Carbon-cement supercapacitors use a very different material system built around cement, carbon black, water and electrolytes.

That does not automatically make them environmentally harmless. Cement production itself is a major source of carbon emissions, and any fair comparison has to consider the complete lifecycle of the system.

The strongest argument for ec³ is therefore not “concrete is green.” It is more subtle.

If society is already going to use concrete for structural purposes, giving some of that concrete an additional energy function could potentially extract more value from material that was going to exist anyway.

That is very different from pouring millions of tonnes of extra concrete solely because somebody wants a battery.

A building material that does more than one job

The broader story here may be bigger than energy storage.

Researchers are increasingly interested in multifunctional concrete: construction materials that do more than carry loads.

Some research investigates concrete that captures or stores carbon dioxide. Other work explores self-sensing materials, self-healing systems, thermal functions and new manufacturing methods.

MIT researchers reported further cement research in 2026 examining what happens chemically when carbon dioxide is injected into cement paste. It is a separate technology from ec³, but it illustrates the same larger shift: concrete is increasingly being treated as an engineered functional material rather than a passive grey substance.

We have seen a similar pattern elsewhere in emerging technology. Our recent look at robots that can feel touch showed how an ordinary physical surface can become a sensing system. Our article on molten-salt batteries explored another attempt to rethink how large amounts of energy could be stored using very different chemistry.

The technologies are unrelated, but the engineering philosophy is similar: redesign familiar materials around the needs of a world that uses far more electricity and far more automation.

Why this probably won't replace normal batteries

It is tempting to frame every new storage technology as “the battery killer.” That is rarely how engineering works.

Different storage systems are good at different jobs.

Lithium-ion batteries have high energy density and a mature manufacturing ecosystem. Pumped hydro can store enormous amounts of energy where geography permits it. Flow batteries, sodium-ion cells, thermal storage and other systems each target different combinations of cost, duration, scale and performance.

Energy-storing concrete may eventually occupy its own niche.

Its greatest advantage is not that it can outperform a lithium battery sitting on a laboratory bench. It is that the storage medium could also be the wall, foundation, bridge component or other piece of infrastructure.

That changes the economics in a way that comparing energy density alone cannot capture.

The hardest test will be boring: decades of reliability

The most exciting technology stories often focus on whether something works once.

Civil engineering asks a harsher question: will it still work after years of rain, heat, freezing temperatures, mechanical stress and maintenance?

Buildings and bridges are expected to last for decades. A multifunctional material has to meet that standard while preserving both its structural and electrical properties.

Connections between cells have to remain reliable. Electrolytes have to remain stable. Damage has to be detectable and manageable. Construction methods have to work outside a carefully controlled laboratory.

And if a section eventually fails electrically, engineers need to know whether it can be repaired without compromising the structure.

Those mundane questions will decide whether ec³ becomes a real construction technology or remains a fascinating research platform.

The bigger idea is hiding in plain sight

Perhaps the most interesting thing about the concrete supercapacitor is how ordinary its ingredients appear.

There is no exotic glowing crystal and no fictional element. The foundation of the idea is cement and carbon — materials humanity already manufactures on enormous scales.

The sophistication comes from understanding what happens when those materials are organized at much smaller scales and then designing the resulting structure to perform two jobs at once.

That is why the technology is worth watching even if energy-storing houses remain years away.

Our cities contain an almost unimaginable amount of passive material. Walls hold things up. Roads provide surfaces. Bridges span gaps.

Future infrastructure may be expected to do more.

A wall could be structure and storage. A road could be transport infrastructure and part of an energy system. A structural component could monitor its own condition while carrying a load.

The concrete around us may continue to look grey and boring.

What it does underneath the surface could become much more interesting.