Design Strategy for High-Performance Thermoelectric Materials: The Prediction of Electron-Doped KZrCuSe ₃

Thermoelectric materials enable direct conversion of heat into electrical energy, providing a promising route for power generation and waste heat recovery. A very active research effort is ongoing to search for high-performance thermoelectric systems including bulk materials and nanocomposites. In this paper, we propose an efficient strategy for identifying thermoelectric materials with high figures of merit among the tens of thousands of known compounds from the inorganic crystal structure database. The search strategy integrates several steps to find materials with a very low lattice thermal conductivity and a high power factor by the virtue of the coexistence of rattling atomic vibrations with favorable electronic band structures. Using our approach, we predict a very high figure of merit (ZT) in electron-doped KZrCuSe ₃ crystals along the crystallographic a-axis, with an estimated average over temperature ZT _ave of about 1.9 from 300 to 1000 K. The overall ZT _ave performance of electron-doped KZrCuSe ₃ is better than most current state-of-the-art thermoelectric materials. Our work supplies not only a current urgent theoretical material prediction, suggesting experimental confirmation, but also a practical materials design strategy that is widely applicable in the search for improved thermoelectrics.