Russian researchers designed a nuclear battery prototype that lasts 100 years.
The cell uses the beta decay of nickel-63 and diamond diodes to achieve 3,300 milliwatt-hours of power per gram—more than any other nuclear battery based on the nickel-63 isotope.
Conventional batteries—those found in most autonomous electrical devices—require redox chemical reactions, in which electrons are transferred from one electrode to another via an electrolyte.
Chemical batteries, also known as galvanic cells, boast a high power density (the ratio between the power of a generated current and the volume of the battery). But they tend to empty out fast; even the rechargeable ones need to be replaced while juicing up.
“This may be dangerous, as in the case of a cardiac pacemaker, or even impossible, if the battery is powering a spacecraft,” according to the Moscow Institute of Physics and Technology (MIPT).
Enter nuclear batteries, invented in 1913 by Henry Moseley, and modernized in 1953, when Paul Rappaport proposed the use of semiconducting materials to convert energy of beta decay into electricity.
The greatest advantage of betavoltaic cells over galvanic cells, MIPT pointed out, is their longevity: Radioactive isotopes used in unclear batteries have half-lives of tens to hundreds of years.
Their power density, however, remains inferior to galvanic cells.
Led by Vladimir Blank, director of the Technological Institute for Superhard and Novel Carbon Materials (TISNCM) and chair of nanostructure physics and chemistry at MIPT, the team developed a way of increasing that dynamic almost tenfold.
The prototype featured 200 diamond converters—a real challenge to manufacture—interlaid with nickel-63 and nickel foil layers. Researchers had to develop a unique system for synthesizing thin diamond plates to mass produce.
“This new technology is important from an economic standpoint,” MIPT said, “because high-quality diamond substrates are very expensive and therefore mass-production of converters by substrate thinning is not feasible.”
With all parts in place, the battery was sealed with epoxy and ready to test.
This is not Russia’s first nuclear-battery rodeo: Scientists from the National University of Science and Technology MISIS in 2016 presented a prototype betavoltaic battery based on nickel-63. Another working model, created at TISNCM and the Research Institute and Scientific Industrial Association LUCH, was demonstrated at Atomexpo 2017.
So why hasn’t the country been getting rich on this technology? A lack of nickel-63 enrichment facilities, according to MIPT, which reported plans to launch production on an industrial scale by the mid-2020s.
Which is good news for medicine and space technology.
The new nuclear battery could power cardiac pacemakers—particularly those machines that require battery replacement and servicing. It could also power autonomous wireless external sensors and memory chips with integrated supply systems on spacecraft.
“The results so far are already quite remarkable,” Blank said in a statement. “But we are planning to do more.
Moving forward, researchers hope to boost voltage and increase battery power output “at least by a factor of three.” They are also working to enhance the surface area of the converter, inflating the number of nickel-63 atoms per converter.
The full results—compiled by scientists at MIPT, TISNCM, and MISIS— were published last month in the journal Diamond and Related Materials.