Lithium-ion batteries power your smartphone, electric vehicle, and wireless earbuds. However, even the best lithium-ion batteries degrade, forcing us into a never-ending cycle of charging and replacing. But what if a single battery could outlast its device — or even its user?

Scientists are now turning to an unlikely source to power mobile devices: nuclear energy. Not the kind that fuels reactors, but a far smaller, safer version that could fit inside everyday gadgets.

The prototype nuclear battery recently unveiled by researchers in South Korea runs on radiocarbon instead of lithium.

“We can put safe nuclear energy into devices the size of a finger,” says Su-Il In, a materials chemist at the Daegu Gyeongbuk Institute of Science & Technology. He presented the new battery this week at the spring meeting of the American Chemical Society in San Diego.

Why Radiocarbon?

Radiocarbon is best known for dating ancient bones and pottery. But this isotope, carbon-14, has another gift: it decays by releasing beta particles — electrons that can generate electricity when they strike certain materials.

Unlike the gamma rays from elements like uranium or plutonium, beta particles are relatively tame. A thin sheet of aluminum is enough to block them, making them far safer for consumer devices.

“I decided to use a radioactive isotope of carbon because it generates only beta rays,” In says. And there’s another perk: radiocarbon is a by-product of nuclear power plants, meaning it’s cheap, widely available, and can be recycled.

Because it decays slowly — with a half-life of 5,730 years — a radiocarbon battery could theoretically last millennia. That’s far beyond even the most durable lithium-ion models, which begin to degrade after a few hundred charging cycles.

How It Works

The prototype developed by In’s team is built around a betavoltaic cell — a type of nuclear battery that converts radiation into electricity. But unlike older versions, this design uses cutting-edge materials to amplify every electron.

Its operating principle hinges on a semiconductor made from titanium dioxide, the same material found in many solar panels. The researchers treated this semiconductor with a ruthenium-based dye, the two of which were more tightly bound to the surface using citric acid. This treatment creates a highly sensitive structure that responds dramatically to incoming beta particles.

When the beta rays from radiocarbon hit the dye, they unleash what’s called an “electron avalanche” — a chain reaction of electrical activity. The electrons surge through the dye into the titanium dioxide, which collects and channels them through an external circuit. The result: electricity.

In previous versions, radiocarbon was placed only on the cathode — the part of the battery where electrons emerge. In the new design, both the cathode and the anode (where electrons flow in) were treated with radiocarbon.

That small change made a big difference.

The team found that dual-electrode radiocarbon treatment more than quintupled the battery’s efficiency — from 0.48% to 2.86%.

Yes, it’s still a modest number, especially when compared to lithium-ion batteries, which routinely exceed 90% energy efficiency in practice. But the trade-off is longevity. While lithium wears out, the radiocarbon battery just keeps going.

What It Could Mean

The South Korean researchers believe this technology could be most useful in medical devices. Despite the knee-jerk reaction to associate anything “nuclear” with “danger”, this particular device is supposed to be safe. A pacemaker, for example, could be powered for an entire lifetime. Today, such implants require surgery every five to ten years to replace batteries. Every surgery carries the risk of life-threatening complications, especially those around the heart.

It could also benefit hard-to-reach sensors — like those buried in infrastructure or deployed in remote environments — where changing batteries is difficult or even impossible.

And as data centers, satellites, and AI systems hunger for uninterrupted power, nuclear batteries that quietly last for decades might offer a powerful solution.

But challenges remain. The current prototype, while a leap forward in efficiency, still produces relatively little power — too little to compete with the punch of a standard Li-ion battery.

“In the current state, the energy conversion efficiency is still low,” In acknowledges. He and his colleagues are already working on improvements — refining the shape of the radiocarbon sources and experimenting with new materials to capture beta particles more effectively.

Whether these finger-sized nuclear batteries will ever find their way into your phone or car remains uncertain. But for now, this technology represents a different kind of atomic power — one that fits in your hand.