Turning cement into a power plant

Researchers have developed a bio-inspired “thermoelectric cement” that harvests energy from temperature differences, offering a potential solution for self-powered buildings and more sustainable infrastructure. The new material, inspired by plant structures, enhances cement’s ability to generate electricity, combining power generation and storage within the same material.

Read the full article at https://www.paperleap.com/blog/articles/turning-cement-into-a-power-plant-with-bioinspired-materials-0cccya

Episode Transcript

Speaker 1 (00:00):
Welcome to the paper Leap podcast, where a science takes
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(00:21):
Don't forget to subscribe so you never miss an insight.
All the content is also available on paper leap dot com. Okay, ready,
let's start. When we think about cement, we usually pictures sidewalks, bridges,
or the walls of skyscrapers that are solid gray and lifeless.
But according to new research, the very material holding up

(00:44):
our buildings could also power them. In a paper published
in Science Bulletin, a team of researchers from Southeast University
and Nanjing, together with collaborators in Japan and South Africa,
suggest exactly that the researchers developed a bio inspired thermoelectric
cement that not always supports buildings, but also harvests energy

(01:06):
from the everyday temperature differences around us. This breakthrough could
help reshape the future of architecture, bringing us one step
closer to self powered buildings. Although we don't think about it. Often,
buildings are hungry beasts, from heating and cooling to lighting
and appliances. They account for about forty percent of global

(01:26):
energy use and roughly a third of all carbon emissions.
Even before a building is finished producing construction materials like
cement already burns through massive amounts of energy. Now, consider
the walls of a house or the pavement of a road.
They're constantly exchanging heat with the environment, absorbing sunlight during

(01:47):
the day, radiating it at night, or cooling under a
chilly breeze. What if we could capture just a fraction
of that wasted energy. That's where thermoelectric materials come in.
These are substances that can can generate electricity when exposed
to a temperature difference, like if one side is heated
by the sun and the other cooled by shade. Traditionally,

(02:09):
these materials are expensive, fragile, or made of toxic elements.
Using them in construction has been impractical, But the researchers
behind this new study had an idea. What if cement
itself could become a thermoelectric generator. Nature as usual had
a solution. If you slice open a plant stem, you'll

(02:30):
see layers of channels that move water and nutrient insufficiently.
Some of these pathways can even selectively trap certain ions
while letting others flow freely. This difference in ion movement
creates the electrical potential in living tissues. The team borrowed
this principle to redesigned cement. They created a cement polyvinyl

(02:50):
alcohol composite CPC, where thin layers of cement are interlaced
with hydrogel, a water rich polymer similar to what you
might find in contact lens is. CPC works with the
cement layers containing calcium ions that naturally want to move
under a temperature gradient. The hydrogel layers then act like
highways for hydroxide ions, which zip belong faster. At the

(03:14):
interface where cement meets hydrogel, calcium ions get selectively immobilized,
essentially trapped, while hydroxide ions keep moving. This difference in
speed between ions is key. It creates a much larger
voltage than cement alone could ever produce. How much better
is this new cement than previous attempts. The numbers are

(03:36):
extremely different. Ordinary cement has a tiny seedback coefficient, a
measure of thermoelectric efficiency of about negative point six two
millivolts per k. The new CPC material reached negative forty
point five millivolts per k, more than sixty times higher.
Its performance metrics, power factor and figure of merit were

(03:58):
five to six times better better than any cement based
material reported so far, and unlike many other experimental thermoelectric materials,
CPC is cheap, safe, and strong. In fact, the layer
design not only improved energy harvesting, but also boosted the
cements mechanical coughness by up to eight hundred and seventy

(04:20):
five percent compared with ordinary cement. That means this could
realistically be poured into walls, bridges, or roads. The team
built small test modules to show how CPC could work.
In practice, blocks of CPC connected in series generated nearly
three quarters of a volt when exposed to a modest
temperature difference. This energy was stored in capacitors, tiny energy

(04:44):
banks that successfully powered an LED light. In larger scale tests,
the CPC acted both as a generator capturing heat differences
and as a supercapacitor, storing the energy for later use.
This dual functionality harvesting and storing energy in the same
material is especially exciting. Imagine a future building where the

(05:05):
very walls are both the power source and the battery.
If adopted widely, bioinspired thermoelectric cement could transform how we
think about energy in cities. We could think about smarter
infrastructure like bridges, pavements, and dams could generate electricity from
daily temperature swings. Even self powered buildings like houses might

(05:28):
power their own sensors, lighting, or communications without external wiring.
Even using cement itself as the energy harvester, avoids the
need for expensive toxic materials is incredibly sustainable. Distributed energy
generation in walls and roads could also support the shift
toward renewable power. The main challenges here are scaling up production,

(05:51):
integrating CPC into existing construction standards, and optimizing real world performance.
These challenges are still ahead, but the concept of turning
the most mundane material of modern civilization into a silent,
ever present power source is one step closer. The idea
that our walls, pavements, and bridges could act like giant

(06:13):
batteries or solar panels would have sounded like science fiction
just a decade ago, but with innovations like this, it's
inching closer to reality. That's it for this episode of
the paper Leap podcast. If you found it thought provoking, fascinating,
or just informative, share it with the fellow science nerd.

(06:35):
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