Concrete is about the least interesting material you’ll ever stand on. It’s the gray stuff poured under your house, the sidewalk that cracks and trips you, the thing every parking lot and freeway overpass is made of, and most people never give it a second thought until a chunk of one falls off an overpass. A team at MIT has spent the last couple of years trying to make the most-used building material on the planet earn its keep a second way: by storing electricity. Their latest version of carbon-laced concrete holds roughly ten times the energy it did two years ago, and it does that while still holding up whatever it was poured into.<\/p>\n
The pitch isn’t a gadget you bolt on. It’s the idea that the wall, the floor, or the foundation could quietly double as the battery. There’s a catch worth flagging up front, and we’ll get to it, but the short version is that this is a supercapacitor doing the work, not a lithium cell, and it’s still very much a lab project.<\/p>\n
The material is called electron-conducting carbon concrete, or ec\u00b3 (you say it “e-c-cubed”), and the recipe is almost insultingly simple. You take cement, water, and ultra-fine carbon black (the same sooty pigment that’s been used in ink for thousands of years, the kind found in some of the oldest writing we’ve dug up) and you mix in an electrolyte. The carbon black does the clever part. Instead of sitting in the cement as dead filler, it links up into a fractal, web-like network threaded all through the concrete’s pores, and that network can hold and release an electric charge.<\/p>\n
That’s the supercapacitor part, and the distinction from a normal battery matters more than it sounds. A battery stores energy in a chemical reaction and hands it back slowly. A supercapacitor parks charge physically, on the surface where the electrolyte meets all that carbon, which means it charges and discharges fast and survives a huge number of cycles without wearing out. The downside is that it holds less energy for its size than a lithium cell does. Concrete has one enormous advantage to make up for that, though: there is a lot of it.<\/p>\n
The jump that got everyone’s attention came down to chemistry. The MIT group, led by civil and environmental engineering professor Admir Masic, swapped a simpler salt-water electrolyte for an organic blend of quaternary ammonium salts and acetonitrile, then used a technique called FIB-SEM tomography (basically shaving off nanometer-thin layers and imaging each one) to map exactly how that carbon web assembles itself. Dialing in the electrolyte and the manufacturing got them a tenfold increase in how much energy the concrete can store. In their 2023 version, according to MIT<\/a>, storing a day’s worth of power for an average home would have taken about 45 cubic meters of the stuff, roughly a basement’s worth of concrete. The new version does the same job in about 5 cubic meters, call it a single basement wall. That’s the headline, and it’s the reason this went from “cute” to “maybe useful.”<\/p>\n None of this is theoretical hand-waving. To prove the concept, the team built a 12-volt, 50-farad supercapacitor module by stacking ec\u00b3 electrodes with porous separators soaked in electrolyte between them, then used it to run a 12-volt computer fan and a 5-volt video game console over USB. It’s a modest thing to power, but the point is that a block of concrete did it. They also cast a roughly 9-volt load-bearing arch, stacked metal weights on top of it to prove it could carry a real structural load, and wired it to a small green LED. The neat part, per the project’s published results<\/a>: as the load on the arch changed, the brightness of the LED changed with it. A structure that tells you how much weight it’s under by how brightly it glows is exactly the kind of thing engineers have wanted for bridge and building monitoring for years.<\/p>\n And it has started creeping out of the lab. Late in 2025 the MIT ec\u00b3 hub took the material to a technical showcase in Fukushima, Japan, alongside the concrete company Aizawa, where they showed off large modular columns that store and release energy while doing the structural job of, well, columns. That’s a long way from a fan and a console, and it’s the direction that actually matters: making the stuff at the size you’d really pour it.<\/p>\n Here’s why anyone cares about a low-density store of electricity. You are not going to win on energy density against lithium, and the MIT team isn’t pretending otherwise. What you win on is that the storage is the structure. Concrete is the single most-used material humans make, by a wide margin, and we pour billions of tons of it every year for foundations, walls, roads, and floors we were going to build regardless. If even a fraction of that can hold a charge, you’ve added storage capacity without buying a separate battery, siting it, and finding room for it.<\/p>\n The most obvious target is an off-grid or solar home, where the foundation soaks up cheap or self-generated power during the day and feeds it back at night, no wall of cells in the garage required. The version that has data center people paying attention uses the structure itself as backup power, an idea DataCenterDynamics<\/a> flagged earlier this year: the concrete holding up the server racks also holding some of the juice to ride through a blip. Back in the original 2023 work, the MIT group even floated concrete roads that wirelessly top up electric cars as they drive over them. That one is a lot further out and leans on a different stack of problems, but it tells you how the people behind ec\u00b3 think about scale.<\/p>\n It’s the same bargain a lot of the more interesting storage ideas are making right now. A silo of hot sand has been quietly heating an entire Finnish town<\/a> through winter by trading electrical efficiency for dirt-cheap, fireproof bulk. Carbon concrete is making a similar trade: give up density, get something else worth having. There’s a tidy symmetry to it within MIT, too. Another MIT team recently worked out a low-temperature way to pull lithium out of hard rock<\/a>, and one of the leftovers from that process is cement-ready silica. The institute is, in a roundabout way, trying to make both the lithium and the concrete cheaper at the same time.<\/p>\n Time to pay off that catch from the top. As impressive as a tenfold jump sounds, ec\u00b3 still stores a small amount of energy for its volume next to a lithium-ion pack, which is why MIT and most of the write-ups describe it as a low-density store. A supercapacitor is built for fast charge and discharge and a long life, not for cramming the most kilowatt-hours into the smallest box. These are also lab prototypes, and commercial use is realistically years out, not months.<\/p>\n There’s a real engineering tension baked into the whole idea, as well. The way you boost how much charge the concrete holds is by packing in more conductive carbon black, and the more of that you add, the more carefully you have to watch what it does to the concrete’s actual day job of bearing weight without cracking. A material that’s a great battery but a mediocre wall solves nothing. That balance, between storage and structure, is the hard problem the ec\u00b3 hub is really working on, and it’s the reason this is a research program and not a product on a shelf.<\/p>\n It helps to know that energy storage is only one piece of what the group is after. Masic frames the real goal as multifunctional concrete, the same material pulling several jobs at once. Since concrete is already the world’s most-used material, he asks, “why not take advantage of that scale to create other benefits?” In their telling, those benefits run from storing energy to self-healing cracks to locking away carbon.<\/p>\n None of that means your house is about to become a giant power bank. The version of this that ends up in a real foundation, if it gets there, is probably a modest top-up that shaves a bit off your grid draw, not a Powerwall poured in place. But the logic is hard to argue with. We already mine, mix, and pour staggering amounts of concrete for reasons that have nothing to do with electricity. Getting even a little useful storage out of material that was going under your floor regardless is the kind of nearly-free win worth chasing, even if the version in your basement is still a few years and a lot of carbon black away.<\/p>\n","protected":false},"excerpt":{"rendered":" Concrete is about the least interesting material you’ll ever stand on. It’s the gray stuff poured under your house, the … <\/p>\nThe prototypes ran a PC fan and a game console<\/h2>\n
The pitch is that the building becomes the battery<\/h2>\n
The honest part is it’s nowhere near a lithium replacement<\/h2>\n