What If We Could Turn Our Houses And Buildings Into Batteries?

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I saw an interesting video on YouTube by Undecided with Matt Ferrell about batteries made from concrete. The video asked, “What if we could turn our houses and buildings themselves into batteries?”

Cement is highly pollutive and is a leading cause of greenhouse gas pollution — it may not be on the level of the transportation industry, but it’s still very high.

Grid operators are investing billions of dollars into lithium-ion batteries. Large-scale energy storage systems are expected to increase 100 times by 2030 but lithium is 2,000 times less abundant than iron. This doesn’t mean lithium’s not abundant (it is), but it does mean iron is a huge potential resource for storage systems.

There are vast amounts of iron (and lithium) on Earth, but much less nickel.

For global industry to scale battery production to ~10 TWh/year, it needs to be mostly iron.

Higher energy density of Nickel only needed for very long range vehicles & aircraft.

— Elon Musk (@elonmusk) September 3, 2021

Matt noted that although lithium-ion batteries have vastly decreased in cost over the past decade, some experts still think that there will be struggles to make the needed improvements in cost, energy density, and charging speed.

This is why, he emphasized, to keep looking for feasible alternatives. One such alternative that Matt based his video on was a prototype developed by the Chalmers University of Technology in Sweden. The prototype they developed was of a rechargeable cement-based battery. The battery has an average energy density of 7 watt-hours per square meter or around 0.7 watt-hours per square foot. It also holds 10 times more power than previously produced cement batteries. And this one is the first rechargeable cement batteries in the world that has been proven at lab scale.

The idea was to integrate concrete batteries into solar panel systems to store the extra energy generated by solar. Matt noted that this invention could have another innovative use case.

“The potential of this invention is its storage capacity scale-up. that’s because you could incorporate this functional concrete into the structure of multi-story buildings to store large volumes of energy. Think of the skyscraper like the Burj Khalifa in Dubai. That will turn it into the biggest battery on the planet.”

In addition to this, you could also cut the costs since concrete is a construction material doubling as an energy storage unit. Imagine wirelessly charging your phone by just putting it on the floor.

“Concrete isn’t a sustainable material by itself, as its production is responsible for 2.4% of the global CO2 emissions. However, while more eco-friendly construction materials are mushrooming like fungus or shooting to the sky like bamboo, we won’t be able to get rid of cement so easily. Being second to water only, cement is the most consumed material on Earth.

“In construction, we use twice as much concrete as all other building materials combined. That’s mostly because of its strength and durability. To add to that, some companies are developing carbon capture systems to trap the CO2 released when making concrete. This could decarbonize the cement production process and make concrete greener but not completely green.

“Why not make the most out of grey concrete and turn huge structures into power banks?”

Matt explained just how this could work. First, he shared how the concrete battery was designed, which was inspired by the battery that Thomas Edison invented.

“In this device, you have ions moving through an electrolyte solution between a positively charged nickel cathode and a negatively charged iron anode. The ions’ motion then generates an electrical potential. The main difference compared to the Edison model is that Swedish scientists used cement mortar as the electrolyte. But they also thought outside of the concrete box, tweaking previous similar models. To make the cement slurry more conductive, researchers spiked it with short carbon fibers.

“Scientists also used an ion exchange resin as a separator between the two electrodes. This porous membrane makes it easy for ions to move from one pole to the other, which increases the ionic conductivity. On top of that, they applied an alternative method for adding the metallic electrodes to the cement paste.”

Matt explained that the conventional technique would have you mix the metallic powder particles with the cement slurry. However, this isn’t safe, especially when using nickel. To make it safer, the researchers coated the nickel and iron onto carbon mesh layers. Next, they slid them into the cement mix where they worked as electrode plates. With this approach, Matt noted, the researchers achieved better electrical performance.

That performance included an energy density that is ten times higher than what they’ve hit when using the powder mixing technique. Matt also explained the reversible electrochemical process of the charging and recharging cycles.

One key worry that he addressed was that if this was to happen, would your home electrocute you? Fortunately, cement is a poor conductor by itself. This would mean that your fingers would be isolated from the electricity that is stored safely inside the battery.

“Turning our houses into giant batteries is electrifying but it’s not just about energy storage. There are a number of other applications to consider for these devices.”

The concrete batteries could be paired with solar cell panels to provide electricity and act as a monitoring system. This, Matt noted, is a great case for highways and bridges.

“Battery-powered sensors would detect any cracks or signs of corrosion before it’s too late. Another study engineered a battery made of cement and seawater to monitor the corrosion of marine infrastructure.

“Building embedded batteries could play a key role in the development of future smart cities by powering automated street LED lighting and Internet of Things-enabled sensors. In their lab test, the Chalmers group used one of their devices to light a small LED lamp for several hours. Another interesting idea would be to use the concrete batteries to provide high-speed WiFi connections for structures in remote areas.”

Matt’s video is pretty educational, and inspiring. Highlighting the innovation being developed in the battery industry and how cement could be used to embed batteries into our buildings is pretty futuristic. Or is it? Is this totally unrealistic when it comes to commercial competitiveness? Or is it something that will one day be the norm?

You can watch Matt’s full video here.