We get a charge (no pun intended) out of reading about ongoing battery research. We love batteries, particularly lithium-ion rechargeables. It is why we started Pale Blue Earth to begin with. At any rate, there will come a day when our products are no longer state-of-the-art. Someday, lithium-ion batteries may be replaced by concrete batteries.
Yes, you read that correctly. Concrete batteries are being worked on right now. Research being conducted at Sweden's Chalmers University of Technology has already proved that a concrete battery is viable – at least at lab scale. Researchers hope to eventually scale things up so that entire buildings, bridges, and other concrete structures can double as rechargeable batteries.
What if your concrete office building were a giant battery? What if it could provide enough energy to make the building 100% powered by solar energy? Researchers say the concrete battery could still twenty years away, but they believe they can make it happen.
The Same Basic Concept
The Chalmers University researchers are not trying to pull rabbits out of a hat as they develop their concrete battery. Rather, they are relying on the same basic concepts that have driven battery development since the 1800s. They just need to find a way to work those basic concepts into a concrete structure.
Every battery, including our USB rechargeable batteries, needs an anode and cathode. In between the anode and cathode is some sort of substance capable of conducting electrons. Put those three things together in a case and you have a battery.
In a concrete battery, the concrete acts as both the case and the conductive material. Yet concrete is not very conductive in its purest form. Therein lies the problem. To overcome that problem, researchers are looking at carbon fiber and a couple of metals.
Reinforcing with Carbon Fiber
A typical concrete structure is reinforced with steel bars known as rebar. Without the rebar, a concrete structure would eventually crack, crumble, and collapse. However, it turns out that rebar is not the best reinforcement material anyway. Scientists having nothing to do with the battery project have been looking at reinforcing concrete with carbon fiber for some years now. It is believed that carbon fiber would offer superior performance over rebar.
Getting back to the battery project, the Swedish researchers reinforced their concrete with small carbon fibers that also increased the material's conductivity. In other words, the small carbon fibers allow electrons to pass through concrete more easily.
As for the anode and cathode, the researchers once again turned to carbon fiber. They created a carbon fiber mesh they embedded in the concrete. One piece of mesh coated with iron was used as the anode. Another piece coated with nickel acted as the cathode. Their design gives them the required anode, cathode, and material for conducting electrons.
Increasing Battery Density
The battery created by the researchers in the lab worked as intended. However, its energy density was not particularly great. So that's what researchers are working on now. They need to be able to increase energy density enough that they do not have to increase the size of concrete structures to make them worthwhile as batteries.
Incidentally, high battery density explains why our USB rechargeable batteries are lighter than their alkaline counterparts. Because we can pack more power into our batteries, they do not need to have as much mass as alkaline batteries. That's just a little factoid we thought you'd like to know.
Someday, concrete structures might double as rechargeable batteries. In the meantime, you can replace your alkaline batteries with our USB rechargeable products and finally ditch disposable batteries.