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Title: Enhanced stability and thermoelectric figure-of-merit in copper selenide by lithium doping

Abstract

Superionic thermoelectric materials have been shown to have high figure-of-merits, leading to expectations for efficient high-temperature thermoelectric generators. These compounds exhibit extremely high cation diffusivity, comparable to that of a liquid, which is believed to be associated with the low thermal conductivity that makes superionic materials good for thermoelectrics. However, the superionic behavior causes cation migration that leads to device deterioration, being the main obstacle for practical applications. It has been reported that lithium doping in superionic Cu2-xSe leads to suppression of the Cu ion diffusivity, but whether the material will retain the promising thermoelectric properties had not yet been investigated. Here, we report a maximum zT>1.4 from Li0.09Cu1.9Se, which is higher than what we find in the undoped samples. The high temperature effective weighted mobility of the doped sample is found higher than Cu2-xSe, while the lattice thermal conductivity remains similar. We find signatures of suppressed bipolar conduction due to an enlarged band gap. Our findings set forth a possible route for tuning the stability of superionic thermoelectric materials.

Authors:
; ; ; ; ; ; ; ; ; ;
Publication Date:
Research Org.:
Argonne National Lab. (ANL), Argonne, IL (United States). Advanced Photon Source (APS)
Sponsoring Org.:
FOREIGN
OSTI Identifier:
1372252
Resource Type:
Journal Article
Resource Relation:
Journal Name: Materials Today Physics; Journal Volume: 1; Journal Issue: C
Country of Publication:
United States
Language:
ENGLISH
Subject:
36 MATERIALS SCIENCE

Citation Formats

Kang, Stephen Dongmin, Pöhls, Jan-Hendrik, Aydemir, Umut, Qiu, Pengfei, Stoumpos, Constantinos C., Hanus, Riley, White, Mary Anne, Shi, Xun, Chen, Lidong, Kanatzidis, Mercouri G., and Snyder, G. Jeffrey. Enhanced stability and thermoelectric figure-of-merit in copper selenide by lithium doping. United States: N. p., 2017. Web. doi:10.1016/j.mtphys.2017.04.002.
Kang, Stephen Dongmin, Pöhls, Jan-Hendrik, Aydemir, Umut, Qiu, Pengfei, Stoumpos, Constantinos C., Hanus, Riley, White, Mary Anne, Shi, Xun, Chen, Lidong, Kanatzidis, Mercouri G., & Snyder, G. Jeffrey. Enhanced stability and thermoelectric figure-of-merit in copper selenide by lithium doping. United States. doi:10.1016/j.mtphys.2017.04.002.
Kang, Stephen Dongmin, Pöhls, Jan-Hendrik, Aydemir, Umut, Qiu, Pengfei, Stoumpos, Constantinos C., Hanus, Riley, White, Mary Anne, Shi, Xun, Chen, Lidong, Kanatzidis, Mercouri G., and Snyder, G. Jeffrey. Thu . "Enhanced stability and thermoelectric figure-of-merit in copper selenide by lithium doping". United States. doi:10.1016/j.mtphys.2017.04.002.
@article{osti_1372252,
title = {Enhanced stability and thermoelectric figure-of-merit in copper selenide by lithium doping},
author = {Kang, Stephen Dongmin and Pöhls, Jan-Hendrik and Aydemir, Umut and Qiu, Pengfei and Stoumpos, Constantinos C. and Hanus, Riley and White, Mary Anne and Shi, Xun and Chen, Lidong and Kanatzidis, Mercouri G. and Snyder, G. Jeffrey},
abstractNote = {Superionic thermoelectric materials have been shown to have high figure-of-merits, leading to expectations for efficient high-temperature thermoelectric generators. These compounds exhibit extremely high cation diffusivity, comparable to that of a liquid, which is believed to be associated with the low thermal conductivity that makes superionic materials good for thermoelectrics. However, the superionic behavior causes cation migration that leads to device deterioration, being the main obstacle for practical applications. It has been reported that lithium doping in superionic Cu2-xSe leads to suppression of the Cu ion diffusivity, but whether the material will retain the promising thermoelectric properties had not yet been investigated. Here, we report a maximum zT>1.4 from Li0.09Cu1.9Se, which is higher than what we find in the undoped samples. The high temperature effective weighted mobility of the doped sample is found higher than Cu2-xSe, while the lattice thermal conductivity remains similar. We find signatures of suppressed bipolar conduction due to an enlarged band gap. Our findings set forth a possible route for tuning the stability of superionic thermoelectric materials.},
doi = {10.1016/j.mtphys.2017.04.002},
journal = {Materials Today Physics},
number = C,
volume = 1,
place = {United States},
year = {Thu Jun 01 00:00:00 EDT 2017},
month = {Thu Jun 01 00:00:00 EDT 2017}
}
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