High-Performance Ionic Thermoelectric Materials by Ionic Doping

Ionic thermoelectric materials have been attracting more and more attention mainly because of their high thermopower. Their thermopower can be tens mV/K, higher than that of electronic thermoelectric materials by 2-3 orders in magnitude. The thermopower of ionic thermoelectric materials arises from the accumulations of cations and anions at the two ends of a sample under temperature gradient. We found that ionic doping can greatly increase the difference in the mobilities of cations and anions and thus improve the thermopower. By ionic doping, we observed high thermoelectric performance on both p-type and n-type thermoelectric materials. The ZTi value can be higher than 6 at room temperature.