If memory serves, the batteries powering the Voyager probes have beta-decay ‘batteries’.
Voyager 1 and 2, are powered by radioisotope thermoelectric generators (RTGs), which convert the heat from the natural radioactive decay of plutonium into electricity. The fuel is Plutonium-238. It is difficult to make . Shortages have led to some missions which would have been ideal with it , like the Titan probe , not using it. (We wait years and years for a probe to get all the way to Saturn, and then use a battery with only a few minutes of use.)