Thermoelectric Generators Generate Electricity Using Temperature Differences... Made Like a Sponge [Science Now]

A domestic research team has developed a technology that improves the shortcomings and strengthens the advantages of a thermoelectric generator that generates electricity from temperature differences by making carbon nanotube (CNT) materials like a sponge.



Since it can freely change its shape, it is expected to be used for small-scale power supply for wearable device sensors that move a lot.



The team of Dr. Han Mi-jeong and Dr. Kang Young-hoon of the Korea Research Institute of Chemical Technology (President Lee Young-guk) has developed a flexible thermoelectric generator that maximizes thermoelectric performance by combining carbon nanotubes and bismuth–antimony–telluride (BiSbTe) in a porous foam form.



The research team of the Korea Research Institute of Chemical Technology has developed a technology that improves the shortcomings and strengthens the advantages of a thermoelectric generator by making carbon nanotube materials like a sponge. [Photo = Korea Research Institute of Chemical Technology]



The research team has been consistently researching carbon nanotube-based thermoelectric materials since 2019. The results of this study are an extension of that research and were announced in January 2025.



Thermoelectric materials are usually made from metal-based inorganic materials. The research team has been developing thermoelectric materials using organic carbon nanotubes. Metal-based thermoelectric materials have high performance but low flexibility.



Existing carbon nanotube thermoelectric materials have limitations in that they are easy to change shape due to their mushy nature, but have low thermoelectric performance and poor mechanical durability.



The research team developed an independent technology to manufacture carbon nanotubes into a voluminous structure to overcome the limitations of low performance while maintaining flexible characteristics.



Conventional organic thermoelectric materials are made in the form of thin, hardened films. Unlike the past, the research team used a method in which material powder is filled into molds of various shapes and heat is applied, solidifying like a sponge after a few hours.



At the same time, a technology was applied to evenly distribute the thermoelectric material into the internal cavities.



By fixing the shape of the material through this, mechanical durability was increased compared to the film form, while thermoelectric performance was also maximized. The irregular pore framework blocked the movement of heat like duck feathers. This



is because when heat movement is slowed, the temperature difference between hot and cold areas is maintained, which leads to good power generation.



The experimental results showed that the thermoelectric performance index (zT) of the CNT/BiSbTe foam was 5.7 times higher than that of the existing CNT foam. An experiment was also conducted in which the newly developed thermoelectric generator was attached to a glass tube and hot and cold water were alternately poured in. It was shown that it could generate 15.7 microwatts (µW) of power when the temperature difference was 21.8 degrees (K, Kelvin), enabling the operation of a low-power temperature sensor. It also



confirmed durability with almost no performance degradation even after repeated bending tests of more than 10,000 times. This manufacturing process is characterized by high productivity as it can produce high-performance thermoelectric materials in just 4 hours, compared to the existing carbon nanotube manufacturing method that takes more than 3 days.



The research team plans to conduct research utilizing the doping process to further improve the thermoelectric performance of this material in the future. It is expected to be commercialized around 2030.



In the future, it plans to expand to new application areas such as solving battery heating problems, artificial intelligence data center cooling systems, and winter temperature maintenance devices by adding various heat control materials inside the carbon nanotubes.



From the right, Researcher Eun-Jin Bae (first author) of the Chemical Research Institute, Principal Researcher Young-Hoon Kang (corresponding author), Principal Researcher Mi-Jeong Han (corresponding author), and Senior Researcher Byeong-



Wook Park (co-author). [Photo = Chemical Research Institute] The research team said, "This study is an important achievement that overcomes the limitations of existing thermoelectric power generation materials and develops flexible energy harvesting technology." President Young-Guk Lee of the Chemical Research Institute said, "This study is an important technology that can be utilized in various fields such as wearable devices and IoT sensors, and we expect it to contribute to the development of energy-independent electronic devices in the future."



This paper (title: High-performance and flexible thermoelectric generator based on a robust carbon nanotube/BiSbTe foam) was published as the back cover paper in the international academic journal 'Carbon Energy' in January 2025. Dr. Young-Hoon Kang and Dr. Mi-Jeong Han of the Chemical Research Institute participated as the corresponding authors, and Postdoctoral Researcher Myeong-Hoon Jeong and Researcher Eun-Jin Bae participated as the first authors.





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