A Battery That Lasts Over 5000 Years: The Chinese Invention Never Dies
A Battery That Lasts Over 5000 Years: The Chinese Invention Never Dies
Research on nuclear batteries has taken a new step forward. A group of researchers from Northwest Normal University, along with experts from Gansu Zhulong Technology, have announced the development of Qianjiyuan Tianshu, a next-generation battery based on the carbon-14 isotope and a silicon carbide (SiC) transducer made in China.
The new device represents an evolution of the Zhulong-1 (Candle Dragon-I) prototype presented in 2024. The goal of the project is to develop more compact, powerful, and economical nuclear batteries intended for industrial applications in addition to those already known in the space sector.
Nuclear batteries, also known as radioisotope or atomic batteries, produce electrical energy by harnessing the decay of a radioactive isotope. Unlike traditional chemical batteries, their lifespan can extend for decades or even centuries, depending on the half-life of the radioactive material used. This feature makes them suitable for use in space probes, environmental sensors installed in remote locations, and implantable medical devices with appropriate radioactive materials.
The technology has already been used in several space missions. NASA employed nuclear batteries in the Voyager probes launched in 1977 and in the Curiosity rover sent to Mars in 2012. China has also used similar systems in the rovers of the lunar missions Chang'e-3 and Chang'e-4.
The proposed Qianjiyuan Tianshu team introduces several improvements over the previous generation. Researchers explain that the radioactive material used has been reduced to 22%, while the power output is 2.6 times higher, without altering the operational voltage and system stability.
"Previous versions suffered from low power, limited integration, and high costs, so the team focused on creating a compact, powerful, economical device made entirely domestically," explained Su Maogen, the project leader at Northwest Normal University.
The carbon-14 betavoltaic battery combined with the SiC energy converter delivers 1.13 μW in its 16.8 cm³ compact package and can theoretically operate for several thousand years. This is sufficient for MEMS sensors, RF-ID tags, low-power microcontrollers in sleep mode, and data loggers.
Among the main innovations are a better matching between the radioactive source and conversion device, a stacked three-dimensional architecture that optimizes available space and increases the level of integration, in addition to a micro-power management system and integrated sensors that allow autonomous operation.
A central role is held by the silicon carbide (SiC) transducer developed in China. Unlike traditional nuclear batteries, which convert the heat from radioactive decay through bulky thermoelectric systems characterized by high operating temperatures, this solution directly utilizes the beta electrons emitted during the decay of carbon-14. The semiconductor converts these particles into electrical current in a manner that researchers say is reminiscent of a solar panel, although it uses radiation instead of light.
From a technical standpoint, the battery occupies a volume of just 16.8 cubic centimeters. It uses 129 millicuries of carbon-14 and reaches a current of 0.713 microamperes, a voltage of 2.06 V, and a maximum power of 1.13 microwatts. The new design reduces the device volume by 17% compared to the previous generation, while the volumetric power density increases by about 15 times.
One of the most interesting aspects pertains to the theoretical lifespan. Carbon-14 has a half-life of 5,730 years, a characteristic that allows the battery to maintain its ability to produce energy for an extremely long period compared to traditional chemical batteries.