Blocking Ion Migration Stabilizes the High Thermoelectric Performance in Cu2 Se Composites
© 2020 Wiley-VCH GmbH.
| Publié dans: | Advanced materials (Deerfield Beach, Fla.). - 1998. - 32(2020), 40 vom: 30. Okt., Seite e2003730 |
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| Auteur principal: | |
| Autres auteurs: | , , , , , , , , , , , , , , |
| Format: | Article en ligne |
| Langue: | English |
| Publié: |
2020
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| Accès à la collection: | Advanced materials (Deerfield Beach, Fla.) |
| Sujets: | Journal Article Cu2Se Schottky junction mixed ionic-electronic conductors stable thermoelectric materials thermoelectric properties |
| Résumé: | © 2020 Wiley-VCH GmbH. The applications of mixed ionic-electronic conductors are limited due to phase instability under a high direct current and large temperature difference. Here, it is shown that Cu2 Se is stabilized through regulating the behaviors of Cu+ ions and electrons in a Schottky heterojunction between the Cu2 Se host matrix and in-situ-formed BiCuSeO nanoparticles. The accumulation of Cu+ ions via an ionic capacitive effect at the Schottky junction under the direct current modifies the space-charge distribution in the electric double layer, which blocks the long-range migration of Cu+ and produces a drastic reduction of Cu+ ion migration by nearly two orders of magnitude. Moreover, this heterojunction impedes electrons transferring from BiCuSeO to Cu2 Se, obstructing the reduction reaction of Cu+ into Cu metal at the interface and hence stabilizes the β-Cu2 Se phase. Furthermore, incorporation of BiCuSeO in Cu2 Se optimizes the carrier concentration and intensifies phonon scattering, contributing to the peak figure of merit ZT value of ≈2.7 at 973 K and high average ZT value of ≈1.5 between 400 and 973 K for the Cu2 Se/BiCuSeO composites. This discovery provides a new avenue for stabilizing mixed ionic-electronic conduction thermoelectrics, and gives fresh insights into controlling ion migration in these ionic-transport-dominated materials |
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| Description: | Date Revised 07.10.2020 published: Print-Electronic Citation Status PubMed-not-MEDLINE |
| ISSN: | 1521-4095 |
| DOI: | 10.1002/adma.202003730 |