Fulfilling thermoelectric promises: β-Zn4Sb3 from materials research to power generation

The beta-phase of Zn4Sb3 was rediscovered as a very promising thermoelectric material in the mid-nineties. The material seemed to have it all: a very high thermoelectric figure of merit in the technologically important mid-temperature region (200-400 degrees C), potential for further optimization through doping and best of all it was made of cheap, "non-toxic'' and abundant elements. A vast amount of waste heat is present in the mid-temperature region, which is likely to be the optimal region for power generation applications. Furthermore, few other attractive thermoelectric materials are known with good performance in this temperature region. Almost 15 years have passed and Zn4Sb3 has still not been built into commercial thermoelectric devices. However, this may change as intensive research appears to have solved some of the significant problematic issues that were unravelled in the last decade. The present Feature presents the Zn4Sb3 story, which touches upon all the major aspects of materials chemistry: synthesis, structural characterization, measurement of properties, materials optimization, device fabrication and commercialization.