High Thermoelectric Performance in Non‐Toxic Earth‐Abundant Copper Sulfide

A new type of high performance thermoelectric material Cu2-xS composed of non-toxic and earth-abundant elements Cu and S is reported. Cu2-xS surprisingly has lower thermal conductivity and more strikingly reduced specific heat compared to the heavier Cu2Se, leading to an increased zT to 1.7. As a service to our authors and readers, this journal provides supporting information supplied by the authors. Such materials are peer reviewed and may be re-organized for online delivery, but are not copy-edited or typeset. Technical support issues arising from supporting information (other than missing files) should be addressed to the authors. Please note: The publisher is not responsible for the content or…