Energy

Novel concrete battery could let buildings store their own energy

Novel concrete battery could l...
A prototype of the concrete battery developed at Chalmers University of Technology
A prototype of the concrete battery developed at Chalmers University of Technology
View 2 Images
A prototype of the concrete battery developed at Chalmers University of Technology
1/2
A prototype of the concrete battery developed at Chalmers University of Technology
A diagram depicting the novel concrete-based battery developed at Chalmers University of Technology
2/2
A diagram depicting the novel concrete-based battery developed at Chalmers University of Technology

One of the more interesting areas of battery research centers on how these devices can not just store energy, but also double as structural components. We've seen some impressive examples of this that could be worked into electric vehicles, and now scientists in Sweden have applied this type of thinking to big buildings, demonstrating a novel type of cement-based battery that could see large structures constructed from functional concrete.

The research was carried out at Chalmers University of Technology, where scientists were working on developing more sustainable building materials, with a particular focus on concrete. As the world's most widely-used material and one that is very energy intensive to produce, we're seeing a lot of research into how the carbon footprint of concrete could be reduced, and the authors of this new study have come up with an interesting potential solution.

Like regular concrete, it starts with a cement-based mixture, but one spiked with small amounts of short carbon fibers to add conductivity and flexural strength. Also incorporated into the mix are a pair of carbon fiber meshes, one coated in iron to act as the battery's anode and the other coated in nickel to act as the cathode. As the battery's two electrodes, these ferry electrons back and forward as the device is charged and discharged.

A diagram depicting the novel concrete-based battery developed at Chalmers University of Technology
A diagram depicting the novel concrete-based battery developed at Chalmers University of Technology

This design was settled upon after much experimentation, with the team looking to improve on previous designs for concrete-based batteries, which they say have performed poorly in testing. This novel, rechargeable design is described as a world-first concept, and in early experiments the team's creative thinking has appeared to bear some fruit.

The concrete-based battery was found to have an energy density of 7 Wh per square meter of material, which the team says could prove more than 10 times greater than previous concrete-based batteries. It is, however, still far lower than commercial batteries, but the fact that it is made of concrete, which can be scaled up to form massive structures, could help counter its limited capacity.

The scientists imagine all sorts of uses for their innovative battery design, starting with buildings that can double as energy storage devices. It could also be used to power LEDs, provide 4G connections in remote areas, or be paired with solar panels to power sensors built into concrete structures, like along highways and bridges.

"We have a vision that in the future this technology could allow for whole sections of multi-story buildings made of functional concrete," says study author Emma Zhang. "Considering that any concrete surface could have a layer of this electrode embedded, we are talking about enormous volumes of functional concrete."

The team notes that it is very early stages for the research, with some technical problems still to iron out. Some of the key questions to answer relate to the lifespan of the battery, as concrete structures are typically made to last decades or more. So the scientists will need to work out either how to make the battery last as long, or come up with a way to extract and replace them once they wear out. In any case, they are optimistic about the possibilities.

"We are convinced this concept makes for a great contribution to allowing future building materials to have additional functions such as renewable energy sources,” says study author Luping Tang.

The research was published in the journal Buildings.

Source: Chalmers University of Technology

11 comments
11 comments
paul314
So for a 200-sq m house you might have about 1.7 kwH of storage (including walls) . Might just be enough to run "smart house" sensors and control systems during an outage. Or you could stow a power bank in the corner.
VincentWolf
Paul314: Yeah but for a home with a basement with 10 inch thick side walls and 6 inch slabs you could have perhaps 3 times that much of about 5 kWH. that's enough to run things for a night without power.
VincentWolf
And don't forget the footings as well. Most basement footings around the country are required to be 24 inches thick by 24" width and that would add another 2 kW so you could on a 3000 sf home have easily a 7 kW of storage--equivalent to a Tesla powerwall.
VincentWolf
And don't forget the post supported homes with up to 10 feet deep 18" circular concreted poured posts to support basement walls in Bentonnite soils. That could add another 1 kW.
*Joe*
Hopefully it's good for more than 1000 recharge cycles so you don't have to rebuild every few years.
Signguy
I will say it again; HEMPCRETE is FAR BETTER than any concrete! Lighter, strong, breathes, acts as a filter for pollutants; FAR BETTER!
HoppyHopkins
What a cool idea, building an Edison battery inside a concrete wall. I like it
SibylTheHeretic
Does the concrete need to be isolated from the earth? In the photo it looks like the concrete is wet and that the concrete slabs may be sitting on damp paper towels in a tray with water? If water is part of the design won't the iron particles corrode?
Karmudjun
Nice pun toward the end Nick: 'problems to still iron out'.
Most concrete is water porous - especially footings and basement walls. One of the destructive forces causing early weakening of concrete structures is water incursion. Placing battery plates inside? Would that continuous back and forth ionic exchange reduce the structural lifespan of the concrete? Would the concrete need to be sealed against water infiltration? Will this construction technique allow for rebar placement or will another strengthening component be required? Possibly the "plates" can be made strong enough - or enough layers included - to replace the rebar. But I'm not holding my breath.
BamPower
Novel yes, practical no. Compressed air in concrete structures like a basement have hundreds of times better energy density at a fraction of the area while providing heating and air conditioning as well as power. I am interested to see what electromagnetic field propagates from building sized batteries, that could be a serious issue.