The development is interesting because no emissions are generated and no maintenance required and provide a use for a particular type of nuclear waste.
The team have demonstrated a prototype ‘diamond battery’ using nickel-63 as the radiation source but are now working to improve efficiency by using carbon-14. It is necessary to enclose the "diamond-battery" in an outer shell, such as another synthetic diamond to absorb stray radiation.
Both nickel-63 and carbon-14 emit beta radiation – high energy electrons – and have half-lives of 101 and 5,730 years, respectively. The half-life is also the measure of how long the battery would take to run-down to half-power. The research team is now working to synthesize a carbon-14 diamond that can be its own radiation source.
While it is not clear what sort of current can be drawn from such unit mass of battery the research is intriguing because it could also represent a way to make use of graphite nuclear waste.
Graphite has been used as a "moderator" in nuclear power reactors and the UK holds 95,000 tonnes of such graphite blocks.
The University of Bristol team has shown that carbon-14 is concentrated near the surface of these blocks easing the extraction of carbon-14 for use in radiation-driven batteries and the ability to reduce the radioactivity of the graphite blocks.
"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," said Tom Scott, Professor in materials at the University of Bristol, in a statement.