Maybe this has been posted before. https://www.popularmechanics.com/science/green-tech/a35970222/radioactive-diamond-battery-will-run-for-28000-years/
This company claims it will have a nanotechnology-based, nuclear-waste-powered, nondepleting battery in production by 2023. I'm not sure whether they have an actual prototype, or whether they explain how ionizing particle radiation is supposedly being contained, but it is being published by many news outlets right now. They say they were going to release, then coronavirus suddenly hit and they had to delay.
