Investigation on the electronic structures, hardness and thermoelectric properties of superionic thermoelectric materials

Among all the state-of-the-art high temperature thermoelectric materials, the superionic Cu2-xSe and Cu2-xS based materials, which have the phonon-liquid electroncrystal (PLEC) structure, exhibit low thermal conductivity and high zT values for their high temperature cubic phases. It has been reported that hot-pressed Cu2-xSe and Cu2-xS polycrystalline bulks show excellent thermoelectric performance, with zT values around 1.5 for Cu1.98Se and 1.7 for Cu1.97S at 1000 K, respectively. The fabrication method requires expensive equipment, however, and lengthy treatment, which obstruct the practical applications of thermoelectric materials. Therefore, it is quite essential to find a low-cost and time-saving method to fabricate highly dense thermoelectric bulk samples.