- Developed ultra-high reliability medium and high temperature thermoelectric power generation device based on the world's first oxide metallization layer

- Formation of metallization layer with conductive indium tin oxide to minimize degradation and maintain excellent output

■ The research team of Dr. Park Sang-hyun of Energy Network Lab. at the Korea Institute of Energy Research (President Kim Jong-Nam) succeeded in developing ‘Ultra-high reliability medium and high temperature thermoelectric element’ based on the world's first oxide metallization layer that can improve the performance limitations of the high-melting-point metal-based metallization technology used in conventional medium and high temperature thermoelectric elements.

■ The existing medium and high temperature thermoelectric element technology formed a metallization layer using a high melting point metal material such as titanium (Ti), and there were many technical difficulties to operate stably for a long time because the operating temperature was high at 300-700 degrees. In particular, the metallization layer, which is the interface connecting the thermoelectric material and the electrode, repeats thermal expansion and contraction at high temperatures, and cracks are generated, so that the device is easily damaged. In addition, even if it is not damaged, diffusion through the metallization layer occurs at a high temperature when being operated for a long time, which may easily lead to deterioration of the thermoelectric material performance of the thermoelectric element.

■ The oxide metallization layer technology developed by the research team for the first time in the world is forming a metalization layer by applying conductive indium tin oxide, which is relatively more stable than metal to the surface of the thermoelectric material at high temperatures. This technology achieved the excellent characteristics of low contact resistance while minimizing the existing diffusion deterioration problem.

■ In particular, as a result of testing the long-term reliability of the device, output of the conventional Ti-based thermoelectric element was reduced in the experiment of thermal repetition up to 500 degrees. However, the oxide metallization layer-based thermoelectric element of this study showed excellent performance with little output drop. In addition, the developed oxide metallization layer device showed excellent stability to suppress diffusion deterioration by about 80% compared conventional Ti metal-based thermoelectric device.

■ Principal researcher Park Sang-hyun said “This oxide-based medium and high temperature thermoelectric technology is a core element technology that can satisfy the ultrahigh reliability energy generation system of 40 to 50 years of continuous operation required by the aerospace industry. This thermoelement device has been developed with differentiated domestic technology. Based on the research results, if a subsequent intensive research targeting the thermoelectric device for the Korean space industry is carried out, it is possible to catch up with the Chinese space industry and lead the further technology.”

■ The results of this study were published in February 2020 in ACS Applied Energy Materials, a leading journal in the field of energy, and were recognized for its academic value.