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.
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