From China comes one of those pieces of news that cannot fail to spark the imagination: a microscopic battery that promises to power smartphones and portable devices of all kinds for a practically unlimited time, without the need for recharging or replacement, and in an absolutely safe way. It was invented by the Chinese company Betavolt Technology, it is based on nuclear energy, has a guaranteed lifespan of 50 years and, according to the company, is destined to revolutionize fields ranging from the world of health to that of smartphones and smart phones. devices, up to military and aerospace applications. Too good to be true? We see.
If you look closely, the idea of harnessing nuclear energy to make disposable batteries is not new. In fact, already in the 1960s and 1970s, these technologies were tested, and even used for some time, in the health field, to power implantable devices such as pacemakers. Since 1973, several companies have launched devices powered by nuclear batteries on the market, which guaranteed the obvious advantage of a ten-year lifespan, thus not requiring the periodic removal of pacemakers with a surgical operation for a trivial reason such as changing the batteries.
The models available were essentially of two types. The first, based on what is called a radioisotope thermoelectric generator, uses a radioisotope which with its own radioactive decay heats the container in which it is stored, and in this way generates electrical energy thanks to a device called a thermoelectric converter. For fuel, the chosen radioisotope was plutonium 238, which being extremely dangerous required a design with many layers of shielding to be safely implanted inside the human body.
A second type of device was based on the so-called betavoltaic effect, which produces electricity from the electrons (or negative beta radiation) produced by the decay of the radioisotope and absorbed by a semiconductor. Even these devices at the time used relatively dangerous isotopes (promethium 162), and therefore required cumbersome shielding to be safely implanted.
In both cases, atomic battery pacemakers posed disposal problems, were bulky, and were swept away from the market by the arrival of lithium batteries, which allowed the creation of slimmer devices with a very respectable lifespan. Both types of nuclear batteries have continued to find a place in the space industry, where the efficiency of a long-lasting battery far outweighs the inconveniences posed by using radioactive materials, but they have rapidly lost ground in civilian technologies . At least until today: technological development, especially in the field of semiconductors, is in fact rapidly changing the cards on the table, ensuring much more efficient energy conversion for betavoltaic batteries, and therefore the use of less radioactive isotopes.
The Chinese battery
The device announced by Betavolt technology was born from the development of a new type of diamond semiconductor, with which the company claims to have been able to create a betavoltaic cell that uses the radioisorope nickel 63, which has a half-life of approximately 100 years ( the time interval necessary for half of the element’s atoms to decay), and it is extremely safe because its low radioactivity makes just 10 microns of skin sufficient to stop the beta radiation that is emitted.
Currently, the battery would be just 15 millimeters wide by five millimeters high (less than a small coin) and would guarantee the production of 100 microwatts for a period of 50 years. The power is extremely low (one microwatt is equal to one millionth of a watt), but the batteries can be used in series and parallel, to power devices that require more power. Even so, around 50,000 would be needed to provide the energy needed to operate smartphones. Currently, therefore, the commercial applications of these new betavoltaic batteries are extremely limited, but the company assures that it can revolutionize things in just a year, promising to launch a 1 watt battery as early as 2025. This would be an increase in power four zeros, which makes at least a pinch of skepticism necessary. If the Chinese company’s claims prove realistic, however, betavoltaic batteries could really revolutionize the way we power many electronic devices, turning battery chargers into a thing of the past. To find out how things will go, however, we just have to wait until next year.