We're lucky Ford never went through with that nuclear car concept. Still, nuclear energy has found its way into devices like pacemakers and spacecrafts thanks to nuclear batteries, which generate electricity from radioactive decay, not fission. Earlier this week, the University of Missouri announced that a team led by Assistant Professor Jae Kwon came up with a new nuclear battery design that's "currently the size and thickness of a penny."
The new battery is aimed at "micro/nanoelectromechanical systems (M/NEMS)," and it purportedly has a power density six orders of magnitude higher than conventional chemical batteries. It's presumably more expensive to make, as well, although the announcement doesn't go into that.
Interestingly, Kwon says he developed the battery using a liquid semiconductor. He explains, "The critical part of using a radioactive battery is that when you harvest the energy, part of the radiation energy can damage the lattice structure of the solid semiconductor. . . By using a liquid semiconductor, we believe we can minimize that problem."
Working together with MU Chemistry Professor J. David Robertson, Kwon hopes to make the battery even smaller—it could become "thinner than the thickness of a human hair," Kwon says. You can see a photo of the current prototype over at Popular Science.