Did you read the article? Nobody is suggesting replacing batteries with this, but 50,000 square miles in the united states is dedicated to roads. What about concrete foundations? Think about how much energy we can store, which is desperately needed for renewable mass adoption.
That's the bullshit part of the article. Cement in an uncontrolled environment is not going to work as a capacitor, even if it works in a controlled environment. Some water will get in. There's expansion and contraction as temperature changes, which causes cracking. The road battery idea belongs in the same category as the road and sidewalk generator idea [1][2], which, in the end, was just an advertising stunt.[3]
The paper jumps directly from showing a tiny effect in a tiny sample to changing the world. This seems to be a disease of battery-related articles.
Also, cement is not the same as concrete. Concrete contains cement as a binder, but is mostly sand and rock. It also absorbs water, which is kind of a problem for a capacitor.
> Cement in an uncontrolled environment is not going to work as a capacitor, even if it works in a controlled environment. Some water will get in.
Concrete always has water. It's part of it's composition. What exactly led you to believe it doesn't?
Also, there's a technology that can turn concrete waterproof which is called paint. In harsh environments it's also mundate to coat rebar with epoxy paints to protect against corrosion.
> There's expansion and contraction as temperature changes, which causes cracking.
Thermal stress in monolithic structures does not cause cracking. At best, it can happen in hyper static structures when thermal strain imposes displacements beyond design limits. This is countered by using technologies such as prestress.
What can cause cracking in concrete is delamination from frosting, where water penetrating through pores expands and detaches concrete blades at the surface. This is prevented by applying a technology called paint.
I saw nothing in your comment that put into question the usage of concrete-based super capacitors. You pointed to known failure modes that are addressed in a very mundane way.
Touché. I guess I'm cautiously optimistic that it can scale (goodness we need good news), but you bring up plenty of valid points. Thanks for putting me in my place.
This is a generic problem with battery announcements. I want to see some publication like Electrek publish 1, 5 and 10 years ago in battery PR.