Tiny 'Nuclear Batteries' Unveiled
Source: BBC (10/8/09)
". . .the batteries hold a million times as much charge as standard batteries."
As radioactive substances decay, they release charged particles that, when properly harvested, can create an electrical current.
Nuclear batteries have been in use for military and aerospace applications, but are typically far larger.
The University of Missouri team says the batteries hold a million times as much charge as standard batteries.
They have developed it in an attempt to scale down power sources for the tiny devices that fall under the category of micro- and nano-electromechanical systems (Mems and Nems).
The means to power such devices has been a subject of study as vigorous as the development of the devices themselves.
Nuclear batteries are an attractive proposition for many applications because the isotopes that power them can provide a useful amount of current for phenomenally long times—up to hundreds of years or more. Thus, they have seen use in spacecraft that are fired far off into the cosmos. But their size has limited their use for applications here on earth.
The UOM team employed a liquid semiconductor to capture and utilize the decay particles.
Most nuclear batteries use a solid semiconductor to harvest the particles, but the particles' extremely high energies means that the semiconductors suffer damage over time.
This means that to build a battery that can last as long as the isotope inside, it must be built larger.
UOM's solution incorporates a liquid semiconductor, in which the particles can pass without causing damage. They are now working to further miniaturize the batteries.
And though the whole idea hinges on the use of radioactive materials, the devices are safe under normal operating conditions.
Nuclear power sources have already been safely powering a variety of devices, such as pacemakers, space satellites and underwater systems.