Concrete "battery" developed at MIT now packs 10 times the power:
Concrete already builds our world, and now it's one step closer to powering it, too. Made by combining cement, water, ultra-fine carbon black (with nanoscale particles), and electrolytes, electron-conducting carbon concrete (ec3, pronounced "e-c-cubed") creates a conductive "nanonetwork" inside concrete that could enable everyday structures like walls, sidewalks, and bridges to store and release electrical energy. In other words, the concrete around us could one day double as giant "batteries."
As MIT researchers report in a new PNAS paper, optimized electrolytes and manufacturing processes have increased the energy storage capacity of the latest ec3 supercapacitors by an order of magnitude. In 2023, storing enough energy to meet the daily needs of the average home would have required about 45 cubic meters of ec3, roughly the amount of concrete used in a typical basement. Now, with the improved electrolyte, that same task can be achieved with about 5 cubic meters, the volume of a typical basement wall.
"A key to the sustainability of concrete is the development of 'multifunctional concrete,' which integrates functionalities like this energy storage, self-healing, and carbon sequestration. Concrete is already the world's most-used construction material, so why not take advantage of that scale to create other benefits?" asks Admir Masic, lead author of the new study, MIT Electron-Conducting Carbon-Cement-Based Materials Hub (EC³ Hub) co-director, and associate professor of civil and environmental engineering (CEE) at MIT.
The improved energy density was made possible by a deeper understanding of how the nanocarbon black network inside ec3 functions and interacts with electrolytes. Using focused ion beams for the sequential removal of thin layers of the ec3 material, followed by high-resolution imaging of each slice with a scanning electron microscope (a technique called FIB-SEM tomography), the team across the EC³ Hub and MIT Concrete Sustainability Hub was able to reconstruct the conductive nanonetwork at the highest resolution yet. This approach allowed the team to discover that the network is essentially a fractal-like "web" that surrounds ec3 pores, which is what allows the electrolyte to infiltrate and for current to flow through the system.
"Understanding how these materials 'assemble' themselves at the nanoscale is key to achieving these new functionalities," adds Masic.
Equipped with their new understanding of the nanonetwork, the team experimented with different electrolytes and their concentrations to see how they impacted energy storage density. As Damian Stefaniuk, first author and EC³ Hub research scientist, highlights, "we found that there is a wide range of electrolytes that could be viable candidates for ec3. This even includes seawater, which could make this a good material for use in coastal and marine applications, perhaps as support structures for offshore wind farms."
At the same time, the team streamlined the way they added electrolytes to the mix. Rather than curing ec3 electrodes and then soaking them in electrolyte, they added the electrolyte directly into the mixing water. Since electrolyte penetration was no longer a limitation, the team could cast thicker electrodes that stored more energy.
The team achieved the greatest performance when they switched to organic electrolytes, especially those that combined quaternary ammonium salts — found in everyday products like disinfectants — with acetonitrile, a clear, conductive liquid often used in industry. A cubic meter of this version of ec3 — about the size of a refrigerator — can store over 2 kilowatt-hours of energy. That's about enough to power an actual refrigerator for a day.
While batteries maintain a higher energy density, ec3 can in principle be incorporated directly into a wide range of architectural elements — from slabs and walls to domes and vaults — and last as long as the structure itself.
"The Ancient Romans made great advances in concrete construction. Massive structures like the Pantheon stand to this day without reinforcement. If we keep up their spirit of combining material science with architectural vision, we could be at the brink of a new architectural revolution with multifunctional concretes like ec3," proposes Masic.
Taking inspiration from Roman architecture, the team built a miniature ec3 arch to show how structural form and energy storage can work together. Operating at 9 volts, the arch supported its own weight and additional load while powering an LED light.
However, something unique happened when the load on the arch increased: the light flickered. This is likely due to the way stress impacts electrical contacts or the distribution of charges. "There may be a kind of self-monitoring capacity here. If we think of an ec3 arch at architectural scale, its output may fluctuate when it's impacted by a stressor like high winds. We may be able to use this as a signal of when and to what extent a structure is stressed, or monitor its overall health in real time," envisions Masic.
The latest developments in ec³ technology bring it a step closer to real-world scalability. It's already been used to heat sidewalk slabs in Sapporo, Japan, due to its thermally conductive properties, representing a potential alternative to salting. "With these higher energy densities and demonstrated value across a broader application space, we now have a powerful and flexible tool that can help us address a wide range of persistent energy challenges," explains Stefaniuk. "One of our biggest motivations was to help enable the renewable energy transition. Solar power, for example, has come a long way in terms of efficiency. However, it can only generate power when there's enough sunlight. So, the question becomes: How do you meet your energy needs at night, or on cloudy days?"
Franz-Josef Ulm, EC³ Hub co-director and CEE professor, continues the thread: "The answer is that you need a way to store and release energy. This has usually meant a battery, which often relies on scarce or harmful materials. We believe that ec3 is a viable substitute, letting our buildings and infrastructure meet our energy storage needs." The team is working toward applications like parking spaces and roads that could charge electric vehicles, as well as homes that can operate fully off the grid.
"What excites us most is that we've taken a material as ancient as concrete and shown that it can do something entirely new," says James Weaver, a co-author on the paper who is an associate professor of design technology and materials science and engineering at Cornell University, as well as a former EC³ Hub researcher. "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."
Paper: "High energy density carbon–cement supercapacitors for architectural energy storage" Check for open access version(s) of the research mentioned in this article.Design Boom
Researchers at MIT have developed electron-conducting carbon concrete, a new kind of cement "that can store and release electricity like batteries," reports Matthew Burgos for Design Boom. "MIT's concrete battery shows a future where the material can be embedded into roads or parking areas to charge electric vehicles directly, or for off-grid homes that do not need external power," Burgos explains.
Journal Reference:
High energy density carbon–cement supercapacitors for architectural energy storage, (DOI: https://www.pnas.org/doi/10.1073/pnas.2511912122)
See also:
(Score: 3, Informative) by c0lo on Monday February 23, @12:49PM (3 children)
So, instead of a concrete "battery", it's "virtually" a supercapacitor
https://www.youtube.com/@ProfSteveKeen https://soylentnews.org/~MichaelDavidCrawford
(Score: 2) by driverless on Monday February 23, @01:07PM (2 children)
It sounds more like a too-good-to-be-true-itor. Can someone who understands more about the tech give an analysis that's presumably going to end up a lot less rosy than the one from MIT's PR department?
(Score: 5, Funny) by gawdonblue on Monday February 23, @08:07PM
It works because electrolytes - it's what concrete craves!
(Score: 2) by corey on Monday February 23, @09:20PM
Yeah, I was wondering about the manufacturability. That’s often omitted.
Wonder if CATL are listening.
(Score: 3, Funny) by suxen on Monday February 23, @01:14PM (5 children)
What happens if you short it out? Does your basement wall burst into flames?
(Score: 3, Interesting) by VLM on Monday February 23, @02:55PM (4 children)
The paper was very handwavy about electrolytes even mentioning seawater.
So overheated electrolyte will either just get steamy or there are some supercap electrolytes that burn quite well.
I wonder about rebar. Will the charge electroytically protect the rebar, make it corrode even faster, or make exposed rebar a shock/fire hazard?
(Score: 3, Interesting) by bussdriver on Monday February 23, @08:59PM (3 children)
There were some other things out there when I saw this last week besides the paper. It appears to be that they put connections on either end; meaning the cement was the center of the capacitor. Just like a normal cap, the metal rods going thru it would kill it's functionality. The images I saw also back this up; so you have electrically isolate the structure into segments to get multiple caps... I wonder how well it works at larger volumes...probably does? What about the discharge rate? 9V but @ many kWh with the amps of capacitor that is a problem. I'm guessing garage floors are a bad idea for storage; good for heating. Thinking of the water capacitors I played with as a kid, nails in the water would have no impact except when they are going through the insulator which is where the prank shocks usually occurred... most the time I overcharged and shocked myself thru the insulator, lol.
Fiberglass rebar would work. Basalt rebar is the best and doesn't conduct; the nail like admix being better than rebar. I would love to know the impact it would have on the mix. I ALSO really want to know what carbonated water does to the process, since that makes cement sequester 20-30% more CO2 yielding the same or greater strength. Their additives should impact strength (by changing the curing as admixes do.)
You still have a structural requirement problem: malleability. rebar saves you during failure because it bends/flows instead of snaps and there is nothing I know of that does this which is not conductive outside of plastic which is quite weak when it's made to be more plastic; unlike iron. It is likely the points where they'd want an electrical contact would overlap where you'd want structural safety rebar; otherwise, it wouldn't likely matter.
Their electrolytes do what when freezing? If they expand like water that is a problem if a cold snap hits them with a few -20F days.
I'm more interested in the Japanese heated sidewalk..
(Score: 2) by VLM on Tuesday February 24, @02:31PM (2 children)
The more I read about this the less interested I am, as typical supercaps use carbon as the storage electrode which is cheap and less environmentally damaging than cement, and the cement caps seem to have all the characteristics that forbid multipurpose use like turning a basement wall into a cap.
(Score: 2) by bussdriver on Wednesday February 25, @07:48PM (1 child)
More people playing with it and gaining more knowledge of it... outside academics; some clever person may find applications to this that nobody thought about. It possibly could be cheaper to modify a basement wall than make a specifically built Cap since you need the wall anyway so if the upgrade is cheaper-- you ALREADY have the space taken up by the wall anyway! A large super cap in the house could be used for many things but the space, cost, and danger are all prohibitive. This could lead to a reasonable solution. So you spend $100 on a segment of a wall. A super cap this large would cost a ton more money. Last time I bought a super cap from china it was $10 and it was tiny. A huge super cap would go a long way to handle power spikes in a house. Especially those short brown outs that wear out all our electronics and shorten their lifespans - I'd like a whole-house power regulator but those cost a ton of money...
Every big motor in my house spikes the system to the point you can see it in the lights. The local power company doesn't regulate the power well; my neighbor's air compressor does it to me too. These are motors with caps on them to minimize this but fail to do enough because my UPS all get triggered long enough to make changeover, sometimes they beep once.
(Score: 2) by VLM on Wednesday February 25, @08:50PM
WRT light dimming there are unwritten classes of Chinese bulbs and I've bought ones with excellent current regulation and others... less so.
A strange long term idea might be big caps across LEDs. Not just for you but in general. That would raise the depth of the trough of current. Hopefully the inrush current wouldn't be too high.
I donno if I count as clever but sometimes an idea will float around in my head for awhile... So water plus electricity might be way too exciting so I was unhappy about the basement all idea. However: What about ground mounted solar panels? Cast a giant cap into the footings of ground mounted solar arrays. If it catches fire, its literally out there in the dirt "this is fine".jpg
Another interesting idea: Ground applications are iffy because of water. But how about a garage wall storage cell to stockpile extra power in a garage when the car isn't plugged in? It may not be super efficient but its free power. It could be an outside wall on a detached garage if it starts on fire at least its "far" from the house.
I bet you get tired of "thank the bussdriver 6876" fortnite jokes. Just having some fun, best of luck to you.
(Score: 3, Funny) by ls671 on Monday February 23, @02:37PM (4 children)
Now build concrete EV cars. They won't need to carry the dead weight of batteries around since the car itself is going to be the battery!
Everything I write is lies, including this sentence.
(Score: 2) by VLM on Monday February 23, @03:01PM
Concrete boats were/are a thing although terribly expensive and very heavy.
Water plus electricity is a non-starter so I don't think this invention will work for boats or basements. Chimneys, maybe.
(Score: 2) by bussdriver on Monday February 23, @09:14PM (2 children)
We NEED grid tied batteries most of all! We don't really need "base load" power generation as industry keeps telling us. Those traditional power plants don't ramp up well, they actually get green power like hydro to reduce power so those fossil plants burn at optimal operating costs. Transport losses are not really high; we can transfer long distance and use storage... plus allow hydro to get utilized more.
If every new house could have some capacitor slabs... even if it's just a wall. You waste a lot having an OVEN in your house that sucks 60amps and forces you to wire your house differently just because it draws spikes of 60amps every few minutes to cook something. Also puts more load on your grid. The EV can smartly charge but your oven is like a welder. If you had a capacitor to power your oven in waves... that 300Wh cooking you do would trickle charge at 20amps. The oven doesn't take more power than your computer it's just the massive spikes that it needs that have you getting 200 amp service and 6 gauge wires on a 60A breaker etc. A DC oven off a super capacitor could also heat up faster than the 60A breaker allows... if designed around such a power source. Imagine near instant boiling water etc. dumping lightning bolt like power... well not going that extreme but do you get the idea? A huge super cap allows for interesting stuff. Downside is you still need thick wires...even thicker with DC 48V code limits... so we still have DC/AC electronics to save on wire costs - in which case, go to 500V AC. it's no more dangerous than 120V AC; most wire shielding I've seen is rated 600V. Unless you start putting ovens next to the concrete wall...
(Score: 2, Interesting) by Anonymous Coward on Tuesday February 24, @01:18AM
> If you had a capacitor to power your oven in waves... that 300Wh cooking you do would trickle charge at 20amps
I contributed a story about "Charlie", a range with Li battery included, but I don't think it ever made the SN front page: https://copperhome.com/products/charlie [copperhome.com] Not cheap in this early limited production run, but according to the article I read (sorry, lost that link) it's in great demand for apartments that are being converted from gas stoves to electric. The 120VAC low peak power requirement saves re-wiring the whole building.
(Score: 2) by VLM on Wednesday February 25, @08:55PM
Someday, someone will invent a heat pump for ovens. Like heat pumps for domestic hot water heating but for cooking.
That would be pleasant for cooking in the summer, the kitchen gets colder as the oven gets hotter.
The relevance to this supercap discussion is float charge a cap so you can dump tons of power into the oven, or heat pump oven, and it'll heat up and broil real fast.
Could I cook a pizza in a "REALLY BIG" electric oven faster than normal people could reheat pizza in a microwave? Well if I dump more KW into the broiler element than a microwave dumps into the magnetron... yeah, I could. I have to think about how big of a cap I'd need to cook a pizza with it. Probably pretty big indeed. But it would be so cool to see.... Imagine a 25 KW pizza and steak broiler, maybe more...