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.
Reference:
Zhang, E.Q.; Tang, L. Rechargeable Concrete Battery. Buildings 2021, 11, 103.
DOI:
https://doi.org/10.3390/buildings11030103