This nuclear battery could power your smartphone forever

Your next smartphone or electric vehicle might be powered by a nuclear battery instead of your usual lithium-ion cell thanks to a breakthrough made by University of Missouri researchers. This is bad news for those of you who think that WiFi signals are bad for your health — especially if they’re received by a smartphone situated near your head or gonads — but great news for all of the people who value all-day battery life ahead of increased radiation exposure. The world could probably do with reduced fertility rates anyway, right?

First, just to put your mind at rest: This nuclear battery doesn’t contain a mini nuclear fission reactor — that would be insane (at least given our current grasp of nuclear power generation, anyway). Instead, this battery, developed by Baek Kim and Jae Kwon at the University of Missouri, uses the betavoltaic process to generate electricity. A betavoltaic device, as the name implies, is fairly similar a photovoltaic device — but instead of generating electricity from photons, it generates electricity from beta radiation — i.e. high-energy electrons that are emitted by radioactive elements. A betavoltaic device is constructed in almost exactly the same way as a photovoltaic cell: a piece of silicon (or other semiconductor) is wedged between two electrodes, and when radiation hits the semiconductor it produces a flow of electrons (voltage, electricity).

“But surely having a battery, and thus a mobile device, packed full of radioactive material is a bad idea” I hear you say. And usually, yes, you’d be right. What makes a betavoltaic battery somewhat safe is that beta radiation can be easily stopped with a thin piece of aluminium; gamma radiation, on the other hand, has so much penetrative power that it can only be stopped by a big lump of lead (or other dense metal). This doesn’t mean that beta radiation in itself is safe — it can cause cancer and death — but it’s much easier to control. Just make sure the betavoltaic nuclear battery casing is more than a couple of millimeters thick — and don’t drop it. Ever.