Wow, literal power bricks.
Classic red bricks are porous and contain iron oxide, which a team in St. Louis has converted into a conductive material for use as a supercapacitor. They hooked up 2 bricks in an electrolyte solution to a AAA battery for a minute and were able to charge a white LED for 11 minutes afterward.
The density isn’t great, but you could use them for things like backup power and emergency lighting.
Turning Bricks Into Supercapacitors
Researchers at Washington University in St. Louis made a fast energy storage device out of common building bricks