Ultrahigh figure‐of‐merit of Cu2Se incorporated with carbon coated boron nanoparticles

Abstract Cu 2 Se based thermoelectric materials are of great potential for high‐temperature energy harvesting due to their high‐temperature figure‐of‐merit ( zT ). For further development of Cu 2 Se, both engineering and mid‐temperature figure‐of‐merit need to be improved. In this work, we report that carbon‐coated boron (C/B) nanoparticles incorporation can significantly improve both mid‐ and high‐temperature z T in Cu 2 Se. The nanoparticle inclusions can result in a homogeneous distribution of Cu:C:B interfaces responsible for both improvement of the Seebeck coefficient and significantly reduction in thermal conductivity. Ultrahigh mid‐ and high temperature thermoelectric performance with zT = 1.7 at 700 K and 2.23 at 1000 K as well as significantly improved engineering zT are achieved in the C/B incorporated Cu 2 Se with desirable mechanical properties and cycling stability. Our findings will stimulate further study and exploration for the Cu 2 Se based thermoelectric materials for broad applications in converting waste heat to electricity with competitive energy conversion efficiency.