Imagine an entire twenty storey concrete building which can store energy like a giant battery. Thanks to unique research from Chalmers University of Technology, Sweden, such a vision could someday be a reality. Researchers from the Department of Architecture and Civil Engineering recently published an article outlining a new concept for rechargeable batteries – made of cement.

The ever-growing need for sustainable building materials poses great challenges for researchers. Doctor Emma Zhang, formerly of Chalmers University of Technology, Sweden, joined Professor Luping Tang’s research group several years ago to search for the building materials of the future. Together they have now 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 fibres added to increase the conductivity and flexural toughness. Then, embedded within the mixture is a metal-coated carbon fibre mesh – iron for the anode, and nickel for the cathode. After much experimentation, this is the prototype which the researchers now present.

“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,” Emma Zhang explains.

Luping Tang and Emma Zhang’s research has produced a rechargeable cement-based battery with an average energy density of 7 Watthours per square metre (or 0.8 Watthours per litre). Energy density is used to express the capacity of the battery, and a modest estimate is that 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 huge volume at which the battery could be constructed when used in buildings.

A potential key to solving energy storage issues

The fact that the battery is rechargeable is its most important quality, and the possibilities for utilisation if the concept is further developed and commercialised are almost staggering.Energy storage is an obvious possiblity, monitoring is another. The researchers see 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,” suggests Emma Zhang.

The concept of using structures and buildings in this way could be revolutionary, because it would offer an alternative solution to the energy crisis, by providing a large volume of energy storage.

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. Emma Zhang comments:

“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”.

Challenges remain with service-life aspects

The idea is still at a very early stage. The technical questions remaining to be solved before commercialisation of the technique can be a reality include extending the service life of the battery, and the development of 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,” says Emma Zhang.

But the researchers are hopeful that their innovation has a lot to offer.

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

Read the scientific article, Rechargeable Concrete Battery in the scientific journal Buildings.

Announced on May 11th, Amsterdam Schiphol is taking sustainability to the next level by using grass to make its own panels for various building projects at the airport. Used at the airport in ceilings, walls, furniture, and flooring, the grass will come from the airport’s own clippings.

“All the grass that would go to waste now gets a second life by serving as raw material. This is fully in line with our ambition to be a waste-free airport in 2030. We aim to be fully circular in 2050.” -Mirjam de Boer, Director of Asset Management at Royal Schiphol Group

A waste-free airport

Apart from facilities at extreme latitudes and those in deserts, airports are typically abundant in grassland, which surrounds vast expanses of runways and taxiways. This grass must be cut regularly to discourage birds from gathering on this land – which in turn decreases the likelihood of bird strikes.

Partnering with ECORⓇ, Schiphol will integrate its own grass clippings into panels used throughout the airport’s construction. The plan will see 100,000 square meters of panels produced annually, using grass clippings as raw material. The airport has around 10 square kilometers of grassland around its runways.

Processing the grass into panels will see it cleaned and pressed without the use of chemicals. Then, “ceilings, partition walls at construction sites, furniture and flooring” will utilize these panels. The airport notes that an added benefit is that the CO2 stored in the grass remains ‘captured,’ as it remains in its solid form.

Although the announcement was made quite recently, Amsterdam Schiphol and ECORⓇ have been collaborating on developing these panels for the last few years now.

Before large-scale production was undertaken, panels were “extensively tested for practical use at the airport,” with the airport saying that they are “certified, fire-resistant and have the same level of quality as the well-known MDF panels.” MDF stands for medium-density fibreboard and is made from wood.

The airport has pledged to purchase the panels made by ECOR®, signing a contract with its building contractors working on site. The rest of the panels, however, will be sold to other parties in the region.

Production to take place locally

The airport hopes to make things even more sustainable, with an ambition to have the grass processed “at or near Schiphol,” thereby reducing emissions further.

At this time, however, processing and production will commence this fall at the ECORⓇ factory in Venlo – a Dutch city that sits near the German border. Venlo is a two-hour drive and some 187km away from Amsterdam Schiphol.

With airports worldwide also maintaining large expanses of grass on their properties, this sounds like a fantastic project that could be transplanted elsewhere. Indeed, this work will make use of something that would otherwise decompose or be incinerated offsite.

Source: Simply Flying