A UNIST research team has developed a new electric cell technology that produces high voltage without external stimulation by mimicking the biological structure of an electric ray. This technology is attracting attention as a key foundation technology for next-generation energy harvesting fields such as wearable power devices and self-powered sensors.

Professor Koh Hyun-hyeop's team from the Department of Energy and Chemical Engineering at UNIST announced on the 21st that they had developed an ultra-thin electric cell just 0.2 mm thick and successfully produced a high voltage of up to 100 V by stacking them.

The research results were published online in Advanced Energy Materials, a world-renowned academic journal in the field of energy materials.

Electric rays produce a low voltage of about 0.1 V per electrocyte, but by stacking thousands of cells, they produce a high voltage of 100 to 200 V.

The research team imitated this principle and created a 'heterojunction electric cell' by placing a positively charged polymer thin film and a negatively charged polymer thin film together.

It is a structure in which an electric field formed at the interface where two thin films come into contact attracts ions and creates a voltage similar to the 'membrane potential' of a biological cell membrane.

The single electric cell developed by the research team recorded a voltage of 0.71 V.

This represents a 30-fold improvement over conventional homojunction structures. The research team stacked these electric cells like those of an electric ray, achieving high voltages exceeding 100 V. Using these, they successfully powered small electronic devices such as 6-watt LED bulbs, electronic calculators, and digital wristwatches.

Durability was also excellent. Even after repeated stretching and resizing of a single electric cell over 3,000 times, there was no voltage loss, and performance was maintained even when stretched up to 1.5 times its original length.

Even when multiple layers were stacked, it responded stably to external deformations such as bending and stretching. The output shows almost no change in various conditions, from dry environments to high humidity environments of 90%, increasing the possibility of application to wearable devices.

Professor Koh Hyun-hyeop explained, “This technology is a source technology that generates high voltage only through the movement of ions within the material without an external energy source,” and “It can overcome the limitations of existing energy harvesting technologies that depend on external stimuli such as wind, sun, and pressure, and significantly reduce the maintenance burden of wearable power devices.”

The research team designed the electrocell based on the phenomenon of "membrane potential," where ions selectively move across biological cell membranes to generate voltage. Professor Koh's team stated, "By mimicking the electrocyte structure of the electric ray and applying a layered method, we were able to stably produce high voltage."

This research was supported by the Ministry of Science and ICT and the National Research Foundation of Korea's Individual Basic Research Program and Nano and Materials Technology Development Program. The research team plans to expand the technology into diverse applications, including wearable power supplies, self-powered sensors, and medical patches.