University researchers create battery powered by waste isotopes
A research team led by scientists at Ohio State University has developed a prototype battery capable of being powered by the ambient gamma radiation given off by the radioisotopes in external nuclear waste.
The researchers—Lei R. (Raymond) Cao and Ibrahim Oksuz of OSU and Sabin Neupane and Yanfa Yan of the University of Toledo—have published their study, titled “Scintillator based nuclear photovoltaic batteries for power generation at microwatts level,” in the February issue of Optical Materials: X.
Cesium-137 and cobalt-60: The team’s experimental battery, which measures about four cubic centimeters, is a type of nuclear photovoltaic battery, which uses a scintillator to convert radiation into visible light, which, in turn, is collected by a photovoltaic (solar) cell to generate electricity. More specifically, the battery is called a gammavoltaic battery, which converts gamma rays emitted by external sources into electricity.
The team tested battery designs with two radioactive isotope sources—cesium-137 and cobalt-60, both of which are fission products found in used nuclear fuel. When Cs-137 was used, the battery generated 288 nanowatts of power. When Co-60 was used, the battery produced 1.5 microwatts. According to an OSU press release announcing the study, the latter amount is “about enough to switch on a tiny sensor.”
The press release also notes that the technology could be scaled up to provide power at the watts level or above, which would expand possible applications. The development of a scaled-up battery capable of generating more power is the logical next step for this research.
Where waste is produced: According to the researchers, these types of batteries would find their best usage at sites where nuclear waste is produced and stored, such as existing nuclear waste storage pools. Gammavoltaic batteries might also find application as part of future nuclear systems for space and deep sea exploration. The radiation at these sites would penetrate into the batteries without the need for the batteries themselves to incorporate radioactive materials.
Scintillator crystal: While developing their prototype, the researchers found that the shape and size of the scintillator crystal were also important. These parameters impact the final electrical output; a larger volume allows the crystal to absorb more radiation and convert that extra energy into more light, while greater surface area also helps the solar cell generate power.
Very promising: The researchers conclude in the abstract of their journal paper, “The experiment presents a scalable option to reach to higher power outputs by harvesting gamma radiation fields in many cases where high radiation field demands heavy shielding and is often regarded as unwanted waste.”
According to Cao, director of the OSU Nuclear Engineering Laboratory, “The nuclear battery concept is very promising. There’s still lots of room for improvement, but I believe in the future, this approach will carve an important space for itself in both the energy production and sensors industry.”
