The demand for sustainable power sources in distributed electronics and wearable devices is growing rapidly. A groundbreaking research project has unveiled a generator inspired by electric rays, offering a stable, scalable, and maintenance-free solution. This innovative technology, developed by researchers at the Ulsan National Institute of Science and Technology (UNIST), mimics the biological mechanism of electric rays to generate power autonomously, without external inputs.
Led by Professor Hyunhyub Ko from the School of Energy and Chemical Engineering, the research team has successfully fabricated a bioinspired bilayer ionic asymmetric stack (BIAS). This 0.2-millimeter-thick ionic heterojunction cell can be stacked to generate voltages exceeding 100V, directly powering electronic devices such as LED lights, calculators, and digital watches without the need for rectification.
Innovative Design Inspired by Nature
The BIAS technology draws inspiration from the electric rays’ ability to generate high voltages through stacked electrocytes. Unlike the rays, which require mechanical stimulation, this new approach produces power autonomously. The core innovation lies in the cell’s structure: an asymmetric bilayer composed of cationic and anionic polymer films. This configuration creates an internal electric field that drives ion migration, generating a voltage similar to biological membrane potential.
According to the research team, a single cell produces approximately 0.71V—more than 30 times higher than symmetric structures. Stacking multiple cells can sustainably power practical electronic devices, offering a promising alternative to conventional batteries.
Durability and Environmental Stability
The BIAS device demonstrated remarkable durability and environmental stability. It maintained voltage output after over 3,000 mechanical stretching cycles and could withstand elongation up to 1.5 times its original length without performance loss. Additionally, it operated reliably across a wide humidity range—from dry conditions to 90% humidity—with minimal power fluctuation.
These qualities suggest strong potential for wearable electronics, where continuous movement and environmental variability are common. The research team, including first authors Seungjae Lee, Youngoh Lee, and Cheolhong Park, explained, “By mimicking the ion-selective membrane potential observed in biological cells, we developed the BIAS—a unit cell capable of generating high voltage autonomously when stacked.”
Potential Impact and Future Applications
Professor Ko emphasized the significance of this technology, stating, “This technology utilizes internal ion migration within the bilayer structure to produce high voltage without any external energy source. Unlike conventional energy harvesting methods relying on wind, sunlight, pressure, or temperature differences, our approach requires no external stimuli, potentially reducing maintenance requirements for wearable power sources.”
The findings of this research have been published in the online version of Advanced Energy Materials, a leading international journal in the field of energy materials published by Wiley, on December 8, 2025. The study has been supported by the National Research Foundation of Korea (NRF) and the Ministry of Science and ICT (MSIT) through projects focused on nanotechnology and energy materials.
Journal Reference: Seungjae Lee, Youngoh Lee, Cheolhong Park, et al., “A Bioinspired Ionic Heterojunction Generator Enabling Stimulus-Free, Scalable Energy Harvesting,” Adv. Energy Mater., (2025).
The implications of this research are profound, with the potential to revolutionize the way we power wearable and distributed electronics. As the technology advances, it could lead to more sustainable and efficient energy solutions, reducing reliance on traditional power sources and minimizing environmental impact.
