Researchers Develop a Penny-Sized Nuclear Battery

A tiny nuclear energy source could help power micro- and
nanomachines of the future.

Nuclear power has long provided steady energy sources for
everything from homes to deep space probes. Now researchers
have begun developing a tiny nuclear battery the size of
a penny that could provide power in a smaller, lighter, and
more efficient package.

Most people probably think of nuclear power that involves
fission and the splitting of atoms. But nuclear power can
also come from the natural radioactive decay of isotopes such
as plutonium-238 -- a much gentler process that has powered
nuclear generators aboard spacecraft such as NASA's Cassini
probe.

Nuclear batteries have also powered more familiar devices on
Earth, such as pacemakers. The higher cost of the batteries
represents the tradeoff for a long-lasting power source that
provides more energy for its size than chemical batteries.

"The radioisotope battery can provide power density that is
six orders of magnitude higher than chemical batteries,"
said Jae Kwon, an electrical and computer engineer at the
University of Missouri.

Kwon and colleagues want to miniaturize such batteries to
power micro-devices and nanotech systems. The batteries won't
pose any fission-related threats, but engineers do face
a challenge in preventing the radioactive decay from
damaging sensitive parts of the batteries.

"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,"

The researchers hope to get around that problem by using
a liquid semiconductor rather than a solid semiconductor.
Eventually they also want to boost battery power, shrink its
size, and eventually end up with a battery thinner than
a human hair.