The innovative method was demonstrated by physicists from the University of Bristol at the Cabot Institute’s “Ideas to change the world” lecture last week. The system devised by the researchers appears to transform power generation while also providing a use for hazardous nuclear waste.
Traditional forms of electricity generation involve using energy to move magnets through coils of wire. This creates an electrical current that can be stored and used to power devices. The mechanism is inefficient though. The generator itself must be supplied with energy to operate and some of what it produces is lost to other forms.
The team at Bristol University found a man-made diamond can produce an electrical charge after being placed in close proximity to a radioactive source. No energy needs to be supplied to the system, increasing its efficiency. There are no moving parts and no additional waste is created.
The group has created a prototype battery that encases a radioactive nickel-63 source with diamond. While the current solution works as a proof of concept, the team hopes to significantly increase efficiency by using carbon-14 as the source. Carbon-14 is a radioactive form of carbon found in small amounts alongside the regular carbon-12 isotope.
Carbon-14 is generated inside the graphite blocks that moderate the nuclear reactions inside power stations. Additional research by Bristol University academics has demonstrated that the majority of the carbon-14 is concentrated at the surface of the blocks, making extraction feasible. Since the U.K. alone is currently storing 95,000 tonnes of used blocks, there’s no shortage of carbon-14 to make the batteries from.
Once obtained, the radioactive material could be contained inside diamond and used to produce a clean and exceptionally long-lasting battery. Carbon-14 has a half-life of 5,730 years, meaning 50 percent of the radioactive nuclei will decay in that time. The diamond battery would be able to last for over 10,000 years, or twice as long as human civilisation has existed.
The impact on society could be monumental but there are still some issues to be worked out. Most importantly, it is currently unknown how much energy the battery would be able to deliver. If 1g of carbon-14 was placed inside the diamond, the battery could produce around 15J of energy a day, less than an AA battery. Using more carbon-14 would deliver more power but increase the risk of exposure to the radiation.
Because of this, the researchers don’t consider the batteries to be suitable for use in smartphones or electric vehicles. However, they could be tasked with powering low-energy, always-on systems such as satellites and drones. The cells could also be used in pacemakers where a long life is essential and replacement extremely difficult. The team is still thinking of other possible applications.
“There are no moving parts, no emissions generated, and no maintenance required, just direct electricity generation,” said Tom Scott, Professor in Materials at the University of Bristol’s Interface Analysis Centre. “By encapsulating radioactive material inside diamonds, we turn a long-term problem of nuclear waste into a nuclear-powered battery and a long-term supply of clean energy.”
