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Using a 2,000-year-old material, MIT engineers turned concrete into the energy storage of the future

concrete blocks with drawings of Robert Downy Jr holding a mineral, buildings, and houses
Image Credit: Augustine Wong // Unsplash. Illustrations by Nate Merritt. Graphic by Miquéla Thornton
  • Mass-scale energy storage is essential for the clean energy transition but supply chain bottlenecks, mineral demand, and lack of infrastructure are barriers to scaling energy storage.

  • MIT researchers found that when mixed with cement powder and water, an ancient charcoal-like material known as carbon black forms a supercapacitor.

  • This technology could serve as an alternative to batteries, and even create concrete that can double as energy storage while offsetting cement emissions.

  • As record-breaking heatwaves overtake the country, the need for energy storage in the face of grid instability and increased gas use becomes even more pertinent.

What if a road could provide contactless recharging for electric cars as they travel? What if a house’s foundation could store enough energy to power the home for a full day?

This is the future that engineers at the Massachusetts Institute of Technology (MIT) dream of achieving with their new concrete developed to store energy.

As described in a study published in this week’s issue of the journal PNAS, the concrete only uses three simple ingredients to achieve a technology that the paper’s authors say “provides a scalable material solution for energy storage to support the urgent transition from fossil fuels to renewable energies.”

Carbon-emitting fossil fuels, aka oil and gas, are the enablers of the climate crisis. According to the authors — which include MIT professors Franz-Josef Ulm, Admir Masic, Yang-Shao Horn, and four other postdoctoral researchers at the university’s Wyss Institute for Biologically Inspired Engineering — to transition from a fossil fuel-based economy at the extent and pace demanded by the rapidly warming planet, bulk energy storage solutions will need to be more available.

Energy storage is essential to stabilizing intermittent renewable power sources like solar panels, wind turbines, and tidal power stations, the researchers explain in their paper.

Storage is what allows these renewables to meet power demand at peak times, which is vital as extreme weather events supercharged by climate change ramp up fossil fuel consumption across the globe.

This is exhibited especially by this summer’s historically deadly heat waves.

The world just experienced the hottest July on record and due to the increased demand for AC and power as heat pressures the electricity grid, the United States just set a record last month for gas use as power plants rushed to power cranked-up air conditioners according to estimates from the market intelligence corporation S&P Global Commodity Insights.

Similarly following China’s remarkable accomplishment of decreasing fossil fuel use to less than half of its power capacity in June, the country’s power plants turned to burning more coal to meet heat-catalyzed electricity demand only a month later.

Research by the U.S. Government Accountability Office (GAO) reports that currently, very little energy is stored in the country. That’s why during dire events like the heat waves leaving already hot cities Phoenix at a scorching 110°F and 20 states from warm California to cool Massachusetts under heat alerts, power plants often turn to immediate power sources like gas to meet needs.

However, according to GAO’s March 2023 report, adding more energy storage could help utilities not only meet demand during supply disruptions but recover faster during outages and better support renewable energy.

Nevertheless, despite the immense benefits of energy storage, GAO says the challenge lies in the fact that “it can be hard to put storage technologies on a grid that wasn't designed for this use.”

GAO’s study outlines how policy can help ameliorate this problem, but according to the MIT researchers, there’s another problem limiting energy storage in the U.S. and across the world: a scarcity of minerals used in current battery technologies that defines whether or not the tech can reach mass scalability.

From solar panels to electric vehicles, clean energy technologies are driving the demand for minerals like lithium and cobalt, however as the Associated Press reports, according to researchers at the International Energy Agency, despite rising demand and output, the industry may face shortages as early as 2025 if enough isn’t invested in production.

So instead of turning futuristic elements in the ground to solve the three-headed problem of energy storage demand, mineral availability, and the lack of storage-friendly infrastructure, the MIT engineers turned to the world’s most ubiquitous and oldest materials: cement, which has been used for thousands of years, and a pigment known as carbon black which dates back to ancient Egypt, China, and Jeruselum, in which it was used for ink on papyrus paper, bamboo strips, and even the ancient Jewish religious manuscript, the Dead Sea Scrolls.

Adding water to the ancient carbon black and cement powder mix, the engineers created a supercapacitor that can act as an alternative to batteries as well as a concrete building material.

Aside from its aptitude for writing hieroglyphics, carbon black is also highly conductive, making it a viable candidate for energy storage, the researchers found. When added to cement, it can make a concrete-like material that the researchers say is just as strong, sturdy, and dense as traditionally made concrete.

“The material is fascinating,” Admir Masic, a sustainable construction scientist at MIT said in the paper’s release.

"Because you have the most-used human-made material in the world, cement, that is combined with carbon black, that is a well-known historical material — the Dead Sea Scrolls were written with it," he said.

"You have these at least two-millennia-old materials that when you combine them in a specific manner you come up with a conductive nanocomposite, and that's when things get really interesting.”

As the mixture evolves, “the carbon black is self-assembling into a connected conductive wire,” he added.

But the most interesting part may be how the researchers hope the material can be used. Initial uses of the technology could be for remote homes, buildings, or shelters that are far from grid power, which could be powered by solar panels attached to the cement supercapacitors, the researchers say.

If used for foundations for houses, the concrete alternative could store a full day's worth of energy while adding little-to-no the cost of the foundation while still providing the needed structural strength.

Lastly, if poured to create new roadways, the researchers say the carbon black concrete could even enable contactless EV charging as vehicles drive, not only providing a potential solution to the energy storage dilemma, but the EV range issue stopping many Americans from going electric.

Aside from the construction and storage applications of the material, it also has implications for planet-warming CO2 emissions. Cement is one of the hardest to decarbonize industries and is responsible for 8% of global CO2 emissions, making it one of the most polluting, albeit necessary, materials on the planet.

While startups like Brimstone are working to lower the emissions of cement production to eventually be zero, the researchers expect the benefits of their supercapacitor could help offset the environmental footprint of current cement production, which last year underwent a domestic production and consumption boom.

But the potential of the material doesn’t end at construction applications.

According to Franz-Josef Ulm, a structural engineer at MIT who led the paper, it is not only more scalable compared to traditional batteries due to its low-cost and abundant materials, but also “multifunctional.” It can even be used as a heating system by simply applying electricity to the carbon black-laced concrete.

As he told the publication Fast Company, after testing a small version of the system in the lab, the team is working on larger iterations — they could have a prototype as soon as 18 months.

According to Ulm via the release, this is “a new way of looking toward the future of concrete as part of the energy transition.”


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