A group of researchers has created a thermoelectric material suitable for wearable technology, including smart textiles, that maintains consistent thermal energy efficiency even under extreme conditions. This innovation successfully addresses the longstanding challenge of balancing high performance with the mechanical flexibility of thermoelectric materials, paving the way for potential commercialization.
A team of Korean researchers has developed a thermoelectric material that is suitable for wearable devices, including smart clothing, while ensuring stable thermal energy performance even in harsh environments. This advancement significantly tackles the challenge of balancing high performance and mechanical flexibility in thermoelectric materials, which has been a persistent issue in this field, and it demonstrates the potential for commercialization.
On the 21st, KAIST (under the leadership of President Kwang-Hyung Lee) announced that a collaborative research team including Professor Yeon Sik Jung from the Department of Materials Science and Engineering and Professor Inkyu Park from the Department of Mechanical Engineering, along with researchers from Hanbat National University and the Korea Institute of Machinery and Materials, has successfully created ‘bismuth telluride (Bi2Te3) thermoelectric fibers.’ This development represents a promising energy harvesting solution for the next-generation of flexible electronic devices.
Thermoelectric materials are capable of generating voltage in response to a temperature difference, allowing for the transformation of thermal energy into electrical energy. Given that around 70% of energy is lost as waste heat, there is a growing interest in these materials for their potential to recover and harness energy from wasted heat.
Many heat sources around us, such as the human body, exhaust pipes, and radiator fins, are often curved in shape. While inorganic thermoelectric materials derived from ceramics exhibit excellent thermoelectric performance, they are brittle and hard to manufacture in curved forms. Alternatively, while flexible thermoelectric materials that utilize traditional polymer binders can adapt to various shapes, their efficiency is limited due to the poor electrical conductivity and high thermal resistance of the polymer.
The conventional flexible thermoelectric materials incorporate polymer additives. However, the inorganic thermoelectric material developed by this research team bypasses these constraints by twisting nano ribbons to create a thread-like structure instead of relying on additives. Leveraging the inherent flexibility of inorganic nano ribbons, the team employed a nanomold-based electron beam deposition method to continuously deposit these nano ribbons and then twist them into fibers composed of bismuth telluride (Bi2Te3).
These new inorganic thermoelectric fibers exhibit improved bending strength compared to previous thermoelectric materials, demonstrating remarkable durability with nearly no alteration in electrical properties even after undergoing more than 1,000 bending and stretching cycles. The thermoelectric device developed by the researchers generates electricity from temperature differences; thus, if textiles are created using these fiber-type thermoelectric devices, they could produce electricity from body heat, potentially powering other electronic gadgets.
Commercialization prospects were confirmed through experiments showing energy collection by embedding these thermoelectric fibers into life vests or clothing. This opens the door to creating efficient energy harvesting systems that recycle waste heat by harnessing the temperature difference between hot fluids inside pipes and the cooler air outside in industrial applications.
Professor Yeon Sik Jung commented, “The inorganic flexible thermoelectric material developed in this study can be integrated into wearable technologies like smart clothing, allowing it to maintain stable performance even in extreme conditions, thereby increasing its potential for future commercialization.” Professor Inkyu Park also highlighted, “This technology is poised to become a vital component of next-generation energy harvesting methods, significantly impacting various sectors from waste heat recovery in industry to personally wearable self-sustaining energy devices.”
This research included contributions from Hanhwi Jang, a Ph.D. candidate at KAIST’s Department of Materials Science and Engineering, Professor Junseong Ahn from Korea University, Sejong Campus, and Dr. Yongrok Jeong from the Korea Atomic Energy Research Institute, all of whom are joint first authors of the study. Their findings were published on September 17 in the online version of the prestigious journal Advanced Materials and were featured as the back-cover article in recognition of its significance. (Paper title: Flexible All-Inorganic Thermoelectric Yarns)
This research was supported by the Mid-career Researcher Support Program and the Future Materials Discovery Program of the National Research Foundation of Korea, along with assistance from the Global Bio-Integrated Materials Center, the Ministry of Trade, Industry and Energy, and the Korea Institute of Industrial Technology Evaluation and Planning (KEIT), under the aegis of the Ministry of Science and ICT.
