Reduction of working temperature for the large magnitude in thermoelectric dimensionless figure of merit of Ag2−x Cu x S

Abstract

In this study, we try to reduce the temperature range for the large magnitude of dimensionless figure of merit ZT = 20 that was observed for the Ag2S composite consisting of low- and high-temperature phases under a unique temperature gradient at around 400 K. It reveals that partial substitution of Cu for Ag sites in Ag2S reduces the phase transition temperature, and subsequently the temperature range for this high ZT down to a temperature of 373 K. This result strongly suggests that our developed Cu-substituted Ag2S could be one of the best thermoelectric component materials in the generators capable of effectively recovering electric power from heat exchangers using hot water as a working liquid.