Apple Would Rejoice at Korea's Technology... "Rescue Signal Using Only Body Temperature"

Development of High-Performance Stretchable Thermoelectric Device
Electricity Generation Using Body Temperature Alone
Operable Level for Wearable Devices

Apple's latest wearable device differentiates itself from rivals like Samsung Electronics by automatically sending a distress signal in the event of a severe fall. But what if the battery runs out? A domestic research team has realized an idea that Apple executives would welcome. They have developed a high-performance stretchable thermoelectric generator that can operate wireless wearable electronic devices using only body heat, without a battery.

The National Research Foundation of Korea announced on the 20th that Professor Hong Yong-taek's research team at Seoul National University, in collaboration with Dr. Jeong Seung-joon’s team at the Korea Institute of Science and Technology (KIST), developed a high-performance stretchable thermoelectric generator that self-generates power using only body heat to operate wireless wearable electronic devices without a battery.

As the use of various forms of wearable electronic devices such as watches and glasses increases, the development of components that can efficiently supply power to related devices is also active. Thermoelectric generators are devices that convert thermal energy into electrical energy through the Seebeck effect. By adding stretchability, they can be attached to human skin, enabling the realization of self-powered wearable devices that operate without batteries using body heat, thus attracting attention as a new power supply component. The Seebeck effect refers to the phenomenon where a potential difference occurs in a closed circuit and current flows when heat is applied to one junction after joining the ends of two different metals.

The power generated by thermoelectric generators is inversely proportional to the internal resistance of the device. Existing stretchable thermoelectric generators have high internal resistance, resulting in low power generation and limited practicality. To realize a high-performance stretchable thermoelectric generator capable of operating external devices, it is necessary to address the interface resistance between the stretchable electrode and thermoelectric material, which is the main factor increasing internal resistance, as well as the electrical resistance of the stretchable electrode.

The research team introduced two strategies to improve the interface and electrical resistance inside the stretchable thermoelectric generator, successfully developing a high-performance stretchable thermoelectric generator with reduced internal resistance and enhanced self-power generation performance. They applied a solution-based welding technique (a process that bonds contact points between two metal particles) to silver-nanowire-based stretchable electrodes to lower internal resistance, and introduced a silver particle-based conductive intermediate layer at the junction between the stretchable electrode and thermoelectric material to reduce interface resistance at the joint.

As a result, the stretchable thermoelectric generator applying both strategies reduced internal resistance by more than six times compared to existing devices, demonstrating world-class power generation performance. Furthermore, it was able to operate a wireless self-powered wearable system capable of Bluetooth communication solely through power generated by body heat, enabling emergency distress signaling without an external power source.

Professor Hong Yong-taek stated, “This research solves the low power generation performance problem, which was considered a technical limitation of existing stretchable thermoelectric generators, and enhances the practicality of stretchable thermoelectric generators by operating wireless wearable devices with small thermal energy such as body heat.” He added, “It is expected to greatly contribute to the popularization and commercialization of battery-free self-powered wearable devices.”

The research results were published as a cover paper in the international energy journal ACS Energy Letters on the 9th.

This content was produced with the assistance of AI translation services.