Does your robot suck batteries dry too fast? Maybe you need to switch to Nuclear Micro-Batteries that can last for decades. More accurately known as Self-reciprocating Radioisotope-powered Cantilevers, these tiny batteries convert radioactivity directly into motion that can be used directly or further converted into electricity. The isotopes were picked with safety in mind. The energy levels of the particles are too low to penetrate human flesh and the batteries are useful until the radiation drops below the normal background levels, so disposal isn't a serious issue. A recent Cornell news release describes the theory. The batteries were developed by Hui Li, Jake Blanchard, and Douglas Henderson. The technical details, as well as a safety assement, can be found in a research paper published by the developers.