Part 2 of 2 Parts (Please read Part 1 first)

South Korean researchers are studying radiocarbon as a source for safe, small and affordable nuclear batteries that could last decades or longer without charging. They have developed a prototype betavoltaic battery powered by the radioactive carbon-14 isotope.

Su-Il In is a professor at Daegu Gyeongbuk Institute of Science & Technology. He presented a report on his work at the spring meeting of the American Chemical Society, held on 23-27 March. Funding for the carbon-14 battery research was supplied by the National Research Foundation of Korea, as well as the Daegu Gyeongbuk Institute of Science & Technology Research & Development Program of the Ministry of Science and Information and Communication Technology of Korea.

With the increasing number of connected devices, data centers and other computing technologies, the demand for long-lasting batteries is rising. In says that the performance of lithium-ion (Li-ion) batteries is “almost saturated”. His team is therefore working on the development of nuclear batteries as an alternative to lithium batteries.

The researchers have produced a prototype betavoltaic battery with carbon-14 which is an unstable and radioactive form of carbon, called radiocarbon. In said, “I decided to use a radioactive isotope of carbon because it generates only beta rays”. A by-product of the operation nuclear power plants, radiocarbon is inexpensive, readily available and easy to recycle. And since radiocarbon degrades very slowly, a radiocarbon-powered battery could theoretically last for millennia.

To significantly improve the energy conversion efficiency of their new design, the Korean team used a titanium dioxide-based semiconductor, a material commonly used in solar cells, sensitized with a ruthenium-based dye. They improved the bond between the titanium dioxide and the dye with a citric acid treatment. When beta rays from radiocarbon collide with the treated ruthenium-based dye, a cascade of electron transfer reactions, called an electron avalanche, takes place. Then the avalanche travels through the dye and the titanium dioxide collects the generated electrons.

The new Korean battery prototype also has radiocarbon in the dye-sensitized anode and a cathode. By treating both electrodes with the radioactive isotope, the researchers increased the quantity of beta rays generated and reduced distance-related beta-radiation energy loss between the two components.

During testing of the prototype battery, the researchers found that beta rays released from radiocarbon on both electrodes triggered the ruthenium-based dye on the anode to generate an electron avalanche that was collected by the titanium dioxide layer and passed through an external circuit resulting in usable electricity.

In said that these long-lasting nuclear batteries could enable many applications. These include powering implants, remote applications, satellites and many more. A pacemaker would last a person’s lifetime, eliminating the need for surgical replacements.

This betavoltaic design converted only a tiny fraction of radioactive decay into electric energy, leading to lower performance when compared to conventional Li-ion batteries. In suggests that further efforts to optimize the shape of the beta-ray emitter and develop more efficient beta-ray absorbers could improve the battery’s performance and increase power generation.

Daegu Gyeongbuk Institute of Science & Technology