CUT’s concept involves adding short carbon fibers into a cement-based mixture, making it more conductive. Then, they integrated a metal-coated carbon-fiber mesh. (Image Credit: Yen Strandqvist/Chalmers University of Technology)
One day, the concrete in large buildings could collect renewable energy. Researchers at the Chalmers University of Technology (CUT) unveiled a new concept for cement-based rechargeable batteries that potentially forms an entire building, storing energy from renewables. It has real-world application possibilities for 4G connectivity, powering LEDs, and cathodic corrosion protection.
Their research builds on previous work that uses concrete to store energy. In their concept, small amounts of short carbon fibers are added into a cement-based mixture to increase its conductivity and flexural strength. Afterward, they integrated a metal-coated carbon-fiber mesh, using iron for the anode and nickel for the cathode. The researchers say that there were performance issues in earlier concrete batteries and that this new mixture improves performance, a world-first.
"Results from earlier studies investigating concrete battery technology showed very low performance, so we realized we had to think out of the box, to come up with another way to produce the electrode. This particular idea that we have developed – which is also rechargeable – has never been explored before. Now we have proof of concept at lab scale," Emma Zhang, study author, said.
The cement-based rechargeable battery performs very well. It has an average energy density of 7Wh per m2 (0.8Wh per liter). They estimate that this battery performs ten times better than earlier models of concrete batteries. However, it still possesses low energy density compared to commercial batteries. That could easily be solved from the large volume when using the battery in the construction of large-scale buildings.
The team said research is in the early stages. They need to provide a solution for a few issues before commercializing the method. One involves making the battery last longer since concrete buildings have a long lifespan. They also want to develop new recycling techniques. "Since concrete infrastructure is usually built to last fifty or even a hundred years, the batteries would need to be refined to match this or to be easier to exchange and recycle when their service life is over. For now, this offers a major challenge from a technical point of view," Zhang said.
Regardless of these obstacles, the team says this battery could have applications for powering LEDs, providing 4G connections, or cathodic corrosion protection in concrete buildings. Their technology could lead to multi-story buildings that also serve as energy storage facilities, providing an alternative for the energy crisis. "We have a vision that in the future, this technology could allow for whole sections of multi-story buildings made of functional concrete. Considering that any concrete surface could have a layer of this electrode embedded, we are talking about enormous volumes of functional concrete,” says Zhang.
"We are convinced this concept makes for a great contribution to allowing future building materials to have additional functions such as renewable energy sources," Luping Tang, another member of the CUT team, explained. Combining this technology with other innovations, such as the AuREUS solar panel, has the potential to turn cities into large renewable energy harvesters.
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