The development of technology that can turn on electronic devices using body heat is expected to accelerate the use of wearable devices and Internet of Things sensors in the future.

Professor Jang Seong-yeon's research team at Ulsan National Institute of Science and Technology (UNIST) announced on the 20th that it has developed the world's first high-performance n-type solid-state thermal galvanic battery that can generate voltage equivalent to that of a AA battery using only body temperature.

This technology is a groundbreaking achievement that could accelerate the commercialization of wearable devices and Internet of Things (IoT) sensors that operate without batteries, and was published in the July 7 issue of the Royal Society of Chemistry (RSC) journal 'Energy & Environmental Science'.

A galvanic cell is a small generator that produces electricity by utilizing the slight temperature difference between the human body temperature (approximately 36°C) and the surrounding air (20-25°C).

Existing technologies have had low output, making it difficult to operate actual electronic devices, but the UNIST research team has significantly improved the current by precisely designing the ion channels of the solid electrolyte.

This enabled simultaneous acquisition of voltage and current, enabling practical power supply.

In particular, the developed battery is made of conductive polymer 'PEDOT:PSS' and Fe(ClO₄)₂/₃ oxide · is based on reduction pairs.

The electrostatic bond between the negatively charged sulfate group (SO₃) and the cation (Fe²/Fe³) within the polymer chain increases structural stability, and provides a path for the anion (ClO₄) to move freely, maximizing battery performance.

The research team connected 100 of these batteries in series to achieve a voltage of approximately 1.5 V, which is similar to that of a regular AA battery.

With just 16 cells, you can actually operate a variety of electronic devices, including LED lights, digital clocks, and temperature and humidity sensors.

The Seebeck coefficient of the unit cell is 40.05 mV/K, which is up to 5 times better than that of existing n-type materials, and durability has also been proven by maintaining the same output even after more than 50 charge/discharge cycles.

Professor Jang Seong-yeon said, “This research has opened new doors in the field of developing flexible thermoelectric conversion devices that utilize low-temperature waste heat,” and “It could serve as the basis for self-powered systems that supply power to wearable devices or autonomous IoT devices.”

This research was supported by the Ministry of Science and ICT and the National Research Foundation of Korea (NRF).