Researchers at Chalmers University of Technology, Sweden have presented an innovative concept for rechargeable batteries made of cement, opening up new possibilities for sustainable and functional building materials.

Dr Emma Zhang, who was previously with the university, joined researchers from the department of architecture and civil engineering led by Professor Luping Tang to successfully develop a world-first prototype for a rechargeable cement-based battery.

The concept uses a cement-based mixture, with small amounts of short carbon fibres added to increase the conductivity and flexural toughness. Embedded within the mixture is a metal-coated carbon fibre mesh – iron for the anode and nickel for the cathode.

“Results from earlier studies investigating concrete battery technology showed very low performance, so we realised 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,” Zhang explained.

The prototype rechargeable cement-based battery has an average energy density of 7 Watthours per square metre (or 0.8 Watthours per litre) – energy density indicates the capacity of the battery. It is estimated that the performance of the new Chalmers battery could be more than ten times that of earlier attempts at concrete batteries. While the energy density is still low in comparison to commercial batteries, this limitation could be overcome by the huge volume at which the battery could be constructed when used in buildings.

The rechargeable property of the battery is its most important quality, presenting immense possibilities in utilisation and commercialisation once the concept is developed further. The research team sees applications that could range from powering 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,” Zhang commented.

Applying the concept in structures and buildings could be revolutionary because it would offer an alternative solution to the energy crisis, by providing a large volume of energy storage. Given that concrete is the world’s most commonly used building material, the potential to add functionality to it could offer a new dimension. 

“We have a vision that in the future this technology could allow for whole sections of multi-storey 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,” Zhang said.

“We are convinced this concept makes for a great contribution to allowing future building materials to have additional functions such as renewable energy sources,” Tang concluded.

The research study was funded by the Swedish Energy Agency (Energimyndigheten).

Photographer: Yen Strandqvist/Chalmers University of Technology