Tom Scott, professor in materials in the University’s Interface Analysis Centre, said: “There are no moving parts involved, no emissions generated and no maintenance required, just direct electricity generation.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.”
The team have demonstrated a prototype ‘diamond battery’ using Nickel-63 as the radiation source. However, they are now working to improve efficiency by utilising radioactive carbon-14, which is generated in graphite blocks used to moderate the reaction in nuclear power plants. Research by academics at Bristol has shown that carbon-14 is concentrated at the surface of these blocks, making it possible to process it with heat to remove the majority of the radioactive material by turning it into a gas. The extracted carbon-14 gas is then incorporated into a diamond to produce a nuclear-powered battery.
The UK currently holds almost 95,000 tonnes of graphite blocks and by extracting carbon-14 from them, their radioactivity decreases, reducing the cost and challenge of safely storing this nuclear waste.
Dr Neil Fox from the School of Chemistry explained: “Carbon-14 was chosen as a source material because it emits a short-range radiation, which is quickly absorbed by any solid material. This would make it dangerous to ingest or touch, but safely held within diamond, no short-range radiation can escape. In fact, diamond is the hardest substance known to man, there is literally nothing we could use that could offer more protection.”
Despite their low-power, relative to current battery technologies, the lifetime of these diamond batteries could revolutionise the powering of devices over long timescales. A standard alkaline AA battery weighing about 20g has an energy storage rating of 700J/g which, if operated continuously, would run out in 24 hours. One of the diamond batteries, containing 1g of carbon-14, would deliver 15 Joules per day and take 5,730 years to reach 50% power, giving an energy storage rating of 2.7 Terajoules.
Prof Scott added: “We envision these batteries to be used in situations where it is not feasible to charge or replace conventional batteries. Obvious applications would be in low-power electrical devices where long life of the energy source is needed, such as pacemakers, satellites, high-altitude drones or even spacecraft.
There are so many possible uses that the scientists have asked the public to come up with suggestions of how they would utilise this technology by using #diamondbattery.