Researchers from University of Houston used inverse design approach to discover several unreported half-Heusler compounds
A team of researchers from University of Houston found a new class of half-Heusler thermoelectric compounds that include one with a record high figure of merit, which is a metric used to determine how efficiently a thermoelectric material can convert heat to electricity. According to physicist Zhifeng Ren, director of the Texas Center for Superconductivity at the University of Houston (TcSUH) and corresponding author of the research, the new compound maintained the high figure of merit at all temperatures. The research was published in the journal Nature Communications on January 17, 2019.
Thermoelectric materials are a potential source of clean energy. According to the researchers, the discovery of half-Heusler compounds composed of tantalum, iron, and antimony yielded results that are vital for thermoelectric power generation. The team measured the conversion efficiency of one compound at 11.4%, which suggests that the material produced 11.4 watts of electricity for every 100 watts of heat absorbed. Theoretical calculations suggest the efficiency can reach 14%, according to Ren. He also stated that several thermoelectric devices are expected to have practical applications with a conversion efficiency of 10%. The team predicted a total of six previously unreported compounds and successfully synthesized one compound that offered high performance without the use of expensive elements.
Moreover, the rest five compounds are stable with the half-Heusler crystal structure and the p-type TaFeSb-based half-Heusler demonstrated an efficient thermoelectric performance. The team relied on theoretical calculations to predict compounds that may have high thermoelectric performance. The team stated that creating materials composed of tantalum, iron, and antimony proved challenging as the components have disparate physical properties. The compound was made using a combination of ball milling and hot pressing. According to the researchers, the compound offered both the physical properties that are required and the mechanical properties that ensure structural integrity. Moreover, the elements used are all relatively available and inexpensive, which makes the compound cost-effective.