Scientists in the US have developed a new fabrication technique that will lead to nuclear batteries that could last for decades. The researchers, based at the University of Rochester, claim that the technique is already ten times more efficient than current nuclear batteries, and has the potential to outstrip them nearly 200 times.

This breakthrough is unlikely to have an impact on your mobile phone or notebook battery life, however. The technology is designed for inaccessible places or under extreme conditions, and is more likely to find its way into pacemakers, implanted defibrillators, deep-space probes or deep-sea sensors, the researchers say.

Although the basic technology - betavoltaics - has been known for around 50 years, low energy yields meant that its usefulness has been limited. Betavoltaics uses silicon to capture electrons emitted from a radioactive gas, such as tritium, to form a current. But this current is less than is generated by a typical solar cell. Part of the problem is that as the radioactive substance decays, most of the electrons miss the silicon surface.

Philippe Fauchet, professor of electrical and computer engineering at the University of Rochester, and co-author of the research commented: "For 50 years, people have been investigating converting simple nuclear decay into usable energy, but the yields were always too low. We've found a way to make the interaction much more efficient, and we hope these findings will lead to a new kind of battery that can pump out energy for years."

What Fauchet and his team have done is to massively increase the surface area where the current is produced. Rather than use a flat collecting surface, he and his team have riddled the silicon with micron-wide pits, using standard semiconductor fabrication technology. Each of the pits will fill with the tritium gas, and as the gas decays, far more of the resulting electrons collide with the silicon surface.

"Our ultimate design has roughly 160 times the surface area of the conventional, flat design," Fauchet concludes.

The research was published in the current issue of Advanced Materials. Read more in the release from Rochester University here. ®

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