Betavolt says its diamond nuclear battery can power devices for 50 years
China's Betavolt New Energy Technology has unveiled a new modular nuclear battery that uses a combination of a nickel-63 (⁶³Ni) radioactive isotope and a 4th-generation diamond semiconductor and can power a device for 50 years.
Nuclear batteries may sound like something super-advanced, but they've been around in one form or another since the early 1950s. Most of these are what are called radio-thermal generators, which turn the heat from decaying radioactive elements into electricity by some sort of thermocouple or a Stirling engine.
In 2016, a new principle was introduced, which uses diamond layers doped with radioactive isotopes – in the case of the first attempt, carbon-14 (¹⁴C). The idea is to select an isotope that releases Beta (β⁻) particles, which are essentially high-energy, high-speed electrons or positrons. When these are released, the diamond matrix acts as a semiconductor to generate an electric current.
Betavolt's new battery, called the BV100, uses two single-crystal diamond semiconductor layers with a thickness of 10 microns each sandwiching a 2-micron layer of ⁶³Ni. Each one of these sandwiches can produce current, but they can also be stacked or linked like old-fashioned voltaic cells to form hundreds of independent unit modules that work together to boost the current.
The whole thing is sealed in a protective case to shield against radiation exposure and to protect the battery against physical damage. The BV100 can produce 100 microwatts at 3 volts and measures 15 x 15 x 5 mm. Beavolt estimates that such batteries could one day power a mobile phone so it never needs recharging or keep a small drone in the air indefinitely.
According to the company, the BV100 is in pilot production with an eye on mass production. A larger one-watt version is expected in 2025. The energy density of the BV100 is rated at 10 times that of lithium batteries and is not prone to fire or explosions. Since it generates electricity rather than stores it in the form of chemical reactions, it is not subject to recharging cycle problems. The ⁶³Ni eventually decays into non-radioactive copper that poses a minimal environmental risk.