Nuclear powered throwies keep Boston on terror alert for sixth decade, seventh on horizon.
Radio-isotope batteries (the same things that have kept the Voyager craft alive since the seventies) can hold a million times as much charge as a standard chemical bettery the same size.
As radioactive isotopes decay, the charged particles they emit are trapped by semiconductors and turned into useful current. Past versions of the battery have used solid semiconductors, which suffer damage from the radiation, so need to be large to survive as long as the isotope.
Now, a team from the University of Missouri has developed a liquid semiconductor that can survive the damage whilst having much less bulk, and have put together batteries the size of a coin. They are working on much smaller versions, capable of powering micro- or nano-scale devices.
Just imagine the possibilities...
University of Missouri - Nuclear battery links