Researchers from the architecture and civil engineering departments at Chalmers University of Technology, Sweden, published an article outlining a new concept for rechargeable batteries—made of cement.
Emma Zhang, formerly of Chalmers University of Technology, joined professor Luping Tang’s research group several years ago to search for the “building materials of the future.” Together they have succeeded in developing a world-first concept for a rechargeable cement-based battery.
The concept involves first a cement-based mixture, with small amounts of short carbon fibers added to increase the conductivity and flexural toughness. Then, embedded within the mixture is a metal-coated carbon fiber mesh—iron for the anode, and nickel for the cathode. After much experimentation, this is the prototype the researchers now present.
“Results from earlier studies investigating concrete battery technology showed low performance, so we realized we had to think out of the box, to come up with another way to produce the electrode,” Zhang said. “This particular idea we have developed, which is also rechargeable, has never been explored before. Now we have proof of concept at lab scale.”
Tang and Zhang’s research produced a rechargeable cement-based battery with an average energy density of 7 Wh/m2 (or 0.8 Wh/L). Energy density is used to express the capacity of the battery, and an estimate is the performance of the new Chalmers battery could be more than ten times that of earlier attempts at concrete batteries. The energy density is still low in comparison to commercial batteries, but this limitation could be overcome thanks to the large volume at which the battery could be constructed when used in buildings.
A potential key to solving energy storage issues
The fact the battery is rechargeable is its most important quality, and the possibilities for utilization if the concept is further developed and commercialized are almost staggering, the university said in a press release. Energy storage is also a possibility, monitoring is another. The researchers see applications ranging from powering light-emitting diodes (LEDs), providing 4G connections in remote areas, or cathodic protection against corrosion in concrete infrastructure.
“It could also be coupled with solar cell panels for example, to provide electricity and become the energy source for monitoring systems in highways or bridges, where sensors operated by a concrete battery could detect cracking or corrosion,” said Zhang.
Concrete, which is formed by mixing cement with other ingredients, is the world’s most commonly used building material. From a sustainability perspective, it is far from ideal, but the potential to add functionality to it could offer a new dimension, the university said.
Challenges remain with service-life aspects
The idea is still at an early stage. The technical questions remaining to be solved before commercialization of the technique can be a reality include extending the service life of the battery, and developing recycling techniques.
“Since concrete infrastructure is usually built to last 50 or even 100 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,” said Zhang.