(Newswire.net — September 18, 2014) — “Betavoltaics, a battery technology that generates power from radiation, has been studied as an energy source since the 1950s,” said Jae W. Kwon, an associate professor of electrical and computer engineering and nuclear engineering in the College of Engineering at MU.
Professor Kwon said that controlled nuclear technologies are not inherently dangerous. “We already have many commercial uses of nuclear technologies in our lives including fire detectors in bedrooms and emergency exit signs in buildings.”
Betavoltaics are generators of electrical current, in effect a form of battery, which use energy from a radioactive source emitting beta particles (electrons). A common source used is the hydrogen isotope, tritium.
Unlike most nuclear power sources, which use nuclear radiation to generate heat, thatthen is used to generate electricity (thermoelectric and thermionic sources), betavoltaics use a non-thermal conversion process; converting the electron-hole pairs produced by the ionization trail of beta particles traversing a semiconductor.
Betavoltaic power sources (and the related technology of alphavoltaic power sources are particularly well-suited to low-power electrical applications where long life of the energy source is needed, such as implantable medical devices or military and space applications.
However, as radioactive material emits, it slowly decreases in activity (refer to half-life). Thus, over time a betavoltaic device will provide less power. For practical devices, this decrease occurs over a period of many years. For tritium devices, the half-life is 12.32 years. In device design, one must account for what battery characteristics are required at end-of-life, and ensure that the beginning-of-life properties take into account the desired usable lifetime.
The battery uses a radioactive isotope called strontium-90 that boosts electro-chemcial energy in a water-based solution. A nanostructured titanium dioxide electrode (the common element found in sunscreens and UV blockers) with a platinum coating collects and effectively converts energy into electrons.
“Water acts as a buffer and surface plasmons created in the device turned out to be very useful in increasing its efficiency,” Kwon said. “The ionic solution is not easily frozen at very low temperatures and could work in a wide variety of applications including car batteries and, if packaged properly, perhaps spacecraft.”
The research, “Plasmon-assisted radiolytic energy conversion in aqueous solutions,” was conducted by Kwon’s research group at MU, and was published in Nature.
Research conducted by Sara Harrison at Stanford University, in 2013, said that the nuclear batteries will have significant advantages over traditional batteries.
“It is well established that conventional electrochemical batteries, despite their widespread use in electronic devices, have limited longevity and a strong tendency to degrade under extreme environmental conditions.” she wrote.