A new nuclear battery produces 10 times the amount of power that commercially available chemical cells produce, packing about 3,300 milliwatt-hours of energy per gram. The battery is powered by the beta decay of nickel-63, a radioactive isotope.
The battery was developed by researchers from the Moscow Institute of Physics and Technology (MIPT), the Technological Institute for Superhard and Novel Carbon Materials (TISNCM), and the National University of Science and Technology MISIS, reports Phys.org.
Producing electric power from nuclear decay is not entirely a new concept notes the report. It was built in 1913, by Henry Moseley based on the beta decay process- where a neutron is converted to a proton and this process creates an electron and an electron antineutrino of radium. He built a battery that was a glass sphere, with a silvered inside and a radium emitter mounted in its centre, placed on an isolated electrode. Electrons that emerged from the beta decay of the radium emitter caused a potential difference between the silver film and the central electrode.
The idea, however, did not take off, notes the report, mostly because the voltage of the nuclear battery was too high, in the tens of kilovolts and the usable current was too low for general use. After this initial breakthrough proved to be not practical, the idea was revisited in 1953 with Paul Rappaport proposing the use of semiconducting materials to convert energy from beta decay to electricity.
Eventually, batteries powered by the beta decay of radioactive materials came to be known as betavoltaics. The main advantage of betavoltaics, notes the report, is their longevity. Radioactive isotopes have half-lives ranging to the hundreds of years. So their power output would remain constant through those years.
One of the biggest challenges for nuclear batteries, notes the report is power density. While they could last long, the amount of power that could be packed into a small battery is really small compared to a lithium-ion battery, for example. The Russian team has seemingly overcome this obstacle.
Researchers used a nickel-63 isotope as the source of radiation and diamond diodes for energy conversion. The battery managed an output of 1 microwatt, with power density per cubic centimetre was measured at 10 microwatts- enough for a modern artificial pacemaker notes the report. The isotope has a half-life of 100 years.
In all, the new Russian nuclear battery packs in about 3,300 milliwatt-hours of power per gram, which is about 10 times more than electrochemical cells.
The scientists are planning to continue their research into nuclear batteries, notes the report. There are still a few more hurdles to overcome if these batteries are to become commercially viable. First, enriching the nickel-63 as the radiation source should proportionally increase battery power output. Second, developing a diamond structure and a controlled profile for it could boost voltage.
This will, in turn, increase the total power output by a factor of three, at the minimum. Third, enhancing the surface area of the diamond converter would increase the number of nickel-63 atoms placed on each converter.
"The results so far are already quite remarkable and can be applied in medicine and space technology, but we are planning to do more... The higher the power density of the device, the more applications it will have. We have decent capabilities for high-quality diamond synthesis, so we are planning to utilize the unique properties of this material for creating new radiation-proof electronic components and designing novel electronic and optical devices."
The study was first published in the journal Diamond and Related Materials.