I think the idea here is to bake it into construction that would happen anyway. If you just need energy storage, keep using batteries. But if you're pouring a foundation already, why not also turn that foundation into a battery?

concrete seems to be used here for its structural properties, just like we do it today. Their solution doesn't seem to require it:

If more powerful capacitors are required, they can be made with a larger concentration of carbon black, at the expense of some structural strength. This could be useful for applications where the concrete is not playing a structural role or where the full strength potential of concrete is not required. For applications such as a foundation, or structural elements of the base of a wind turbine, the “sweet spot” is around 10 percent carbon black in the mix, the team says.

Yeah they’ll scoop up the technology patents and then slowly utilize it if and when it works in their favor to maximize their profits

I mean, its not clear you want to build a house out of concrete walls that aren't entirely, well, concrete. Even so, its a neat idea, but coming out of the MIT press mill, I'll not be holding my breath for it to become real. MIT is basically a meme at this point with regards to press releases that don't manifest into reality.

naturally it depends on the walls and house layout, but just to have an idea: assuming a concrete thickness of 20cm and 4 external walls of 20m x 3m each:

0.2 * 4 * 20 * 3 = 48m^3

probably in the 100-200m^3 ballpark if we count internal walls, which are thinner, but cover more total length.

And I know walls are usually not pure concrete, but functions like energy storage could very well change how we build them.

I wonder if the foundation of the house would be convenient for this… that much concrete is equivalent to a cube of side length around 10 feet, which seems to at least be in the ballpark for the total amount of concrete in a foundation. I think?

For a basement with a 5-inch slab and exterior walls are 8 inches, 8ft high and also concrete... Then 45 cubic meters is about what you'd need.

Of course, your basement walls are about as electrically grounded as it gets, so I doubt you'd be able to store power in them. One leak and you're discharging all that power into the groundwater.

10kWh is enough to run one 110VAC outlet at full capacity for about 10 hours. I don't know where that 10kWh figure comes from but most American houses use between 15-30kWh per day.

So that 10 foot cube would need to be closer to 15ft cubed. It's huge. Perhaps the foundation of the structure would work, as someone else mentioned.

It's more nuanced than that. The question is whether we're just using carbon black that's already an excess byproduct of other industries, or we'd be actively producing it to make these wall batteries.