New battery has incredibly long life, may never need recharging
A research team at the Daegu Gyeongbuk Institute of Science and Technology (DGIST) led by Professor Su-Il In has developed a new type of nuclear battery called a perovskite betavoltaic battery (PBC) that can power small devices for decades without needing to be recharged. The team used carbon-14—an unstable form of carbon known as radioactive carbon—and combined it with perovskite materials to create a hybrid battery with improved energy conversion and long-term stability.
The new battery uses carbon-14 nanoparticles and quantum dots (14CNP/CQD) as electrodes. They are embedded in the device along with a perovskite film treated with two chlorine-based additives: methylammonium chloride (MACl) and cesium chloride (CsCl). These additives help strengthen the perovskite crystal structure, resulting in a stable structure and better charge mobility. Compared to previous designs, the team recorded an approximately 56,000-fold improvement in electron mobility and a maximum continuous operating time of 9 hours during testing.
'This study represents the first successful integration of perovskite into a betavoltaic battery, pioneering the field of perovskite betavoltaic batteries,' the researchers claim.
Betavoltaic batteries work by converting beta particles—emitted during radioactive decay—into electricity. Because beta rays cannot penetrate human skin and can be blocked by materials such as aluminum, the technology is considered biosafe. 'I decided to use a radioactive isotope of carbon because it only produces beta rays,' explains Professor In. Carbon-14 is also a byproduct of nuclear reactors, making it cheap, widely available, and recyclable. Because it decays so slowly, carbon-14 can power devices for hundreds or even thousands of years.
To improve the energy conversion efficiency—a measure of how well the battery converts electrons into usable energy—the team turned to the semiconductor titanium dioxide, commonly found in solar cells, and enhanced it with a ruthenium-based dye. The bond between the dye and the titanium dioxide was strengthened by treating it with citric acid. When beta rays from radioactive carbon hit the dye, they triggered a chain reaction of electrons known as the avalanche effect. These electrons were then 'captured' by the titanium dioxide and sent through a circuit to create an electric current.
The battery is also designed with radioactive carbon at both the anode and cathode, increasing the amount of beta radiation and reducing energy loss over distance. This approach increases the energy conversion efficiency from 0.48% in older models to 2.86%.
However, the system only converts a small fraction of the radioactive energy into electricity, meaning its output is still lower than that of a standard lithium-ion battery. Professor In suggests that improving the shape of the beta emitter and finding better absorbers could further increase the output.
This research marks the world's first practical demonstration of the feasibility of betavoltaic batteries. We could put safe nuclear power into devices the size of a finger.
The team believes that, with future improvements, these radioactive carbon-powered batteries could be used in areas ranging from pacemakers to space probes and drones.
