When you picture a sci-fi energy source, glowing green crystals are right up there. Scientists in China have now demonstrated just that, in the form of a “micronuclear battery” that can provide continuous low levels of power for decades.
The concept of a nuclear battery has been around for a long time, and while there are a few different variations it’s all about tapping into the energy consistently being thrown off of radioactive materials. Some designs directly convert the radiation into electricity, while others capture their heat or light energy and turn that into electricity.
The newest prototype falls into that last category – it captures light from an almost cartoonish glowing green crystal. The energy source is a small amount of the radioactive element americium, embedded in a polymer crystal that converts the radiation into a stable green glow, eerily similar to those old stars everyone had stuck to their childhood bedroom ceiling.
The crystal is then paired with a thin photovoltaic cell to convert that light into electricity, and the whole thing is encased in quartz to prevent radiation leaking.
Over hundreds of hours of testing, the team says the micronuclear battery provided a steady output of electricity, and would probably continue to do so for decades without interruption. It was more than 8,000 times more efficient than previous designs.
That said, we are talking about tiny amounts of energy here. That power conversion efficiency was just 0.889%, with the battery producing 139 microwatts per curie (a unit of radioactivity).
Still, such a device could come in handy for a few applications, especially for low-power sensors and devices that need to run unsupervised for long periods, where charging or changing batteries is impractical. Think the bottom of the sea, or deep space, where versions of nuclear batteries are already used. Radioactive decay will just keep on producing energy regardless of environmental factors like temperature, pressure or magnetic fields.