New Chinese nuclear battery

Text by Matheus Pereira, chemical engineer and Russian Nuclear Education Ambassador (RNEA)

On July 6, 2026, the Northwest Normal University (NWNU), in partnership with the technology company Gansu Zhulong Technology, officially unveiled to the world a new solid-state nuclear battery called “Qianjiyuan Tianshu” (or “Millennium Celestial Pillar”). It is a miniature radioisotope thermoelectric generator (RTG) that uses the carbon-14 (¹⁴C) isotope as its primary energy source and a silicon carbide (SiC) semiconductor converter for the direct conversion of beta radiation into electrical current. The major advantage touted is complete technological self-sufficiency: according to the developers, the entire project—from the purification of the fissile material to the encapsulation of the converter—was carried out without relying on foreign technologies or components, positioning this device as a milestone in China’s strategy for self-sufficiency in micro-nuclear technology.

Compared to the previous prototype (Zhulong-1, from 2024), the new generation features substantial improvements in critical design parameters. The efficiency of radioactive material utilization has been optimized, reducing the specific consumption of ¹⁴C to just 22% of the volume previously used, which enhances safety and reduces manufacturing costs. At the same time, the short-circuit current has been increased by a factor of 2.5, while the maximum output power has increased 2.6-fold. The most notable improvement, however, lies in miniaturization and energy density: the physical volume of the device was reduced to 17% of its original size, and the volumetric power density showed an extraordinary 15.5-fold increase. Measuring approximately 16.8 cm³, the component operates at a nominal voltage of 2.06 V and a power of about 1.13 microwatts.

From a systems engineering perspective, the battery has been qualified for operation under extreme environmental conditions, withstanding a temperature range from -100 °C to +200 °C, making it suitable for applications in space probes, polar exploration vehicles, and deep-sea submersible equipment—niches in which conventional chemical batteries suffer catastrophic failures due to electrolyte freezing or overheating. The most disruptive factor, however, is its intrinsic longevity: given that the half-life of carbon-14 is 5,730 years, the decay curve of the primary source ensures that the generated current remains above 50% of its initial value for millennia, eliminating the need for replacement or recharging over multiple generations of equipment.

The most interesting aspect is the applications. They focus on high-value-added, low-power systems, such as cardiac pacemakers, deep neurological implants, autonomous sensors for critical infrastructure (monitoring bridges and pipelines in remote regions), and avionics for long-duration missions. However, it is essential to note, from the perspective of device physics, that the power supplied is on the order of microwatts—sufficient to power low-power sensors and clocks, but completely insufficient to drive motors, high-performance processors, or continuous communication systems. We can therefore say that this advancement does not represent a replacement for lithium batteries in consumer electronics, but rather the introduction of a new class of primary energy sources for missions requiring decades-long autonomy.