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Manipulating the phase transformation temperature to achieve cubic Cu5FeS4-xSex and enhanced thermoelectric performance
Guo, Lijie1; Zhang, Bin2; Zhu, Huaxing1; Wu, Hong1; Yan, Yanci1; Gong, Xiangnan2; Lu, Xu1; Han, Guang3; Wang, Guoyu4,5; Zhou, Xiaoyuan1,2
2020-12-28
摘要Cu5FeS4, one of the promising Earth-abundant and low-toxicity Cu-based thermoelectric materials, transforms from an orthorhombic structure to a cubic phase when heated, which may impede its applications at elevated temperatures. Herein, we demonstrate that the phase transformation temperature of Cu5FeS4 can be suppressed to lower temperatures by replacing S by Se, as demonstrated in a series of Cu5FeS4-xSex (x = 0, 0.4, 0.8, 1.5, 2.0) compounds. Upon increasing the Se content x from 0 to 2.0, the phase transformation of Cu5FeS4-xSex takes place at progressively lower temperatures, with Cu5FeS2Se2 having a high cubic structure at room temperature. The Se-substituted Cu5FeS4 compounds achieve tremendously improved electrical performance, which is consistent with the calculated higher transport coefficient and weighted mobility. Combined with the still low lattice thermal conductivity, the Se-substituted Cu5FeS4 compounds achieve improved zT, for example, an improved peak zT of similar to 0.6 at 735 K in Cu5FeS3.6Se0.4, and an average zT of similar to 0.42 from 300 to 735 K in Cu5FeS2.5Se1.5 that is about 130% higher than that of Cu5FeS4. This study sheds light on enhancement of the thermoelectric performance of Cu5FeS4 based materials via manipulation of their phase transformation temperature.
DOI10.1039/d0tc04179c
发表期刊JOURNAL OF MATERIALS CHEMISTRY C
ISSN2050-7526
卷号8期号:48页码:17222-17228
通讯作者Han, Guang(guang.han@cqu.edu.cn) ; Wang, Guoyu(guoyuw@cigit.ac.cn) ; Zhou, Xiaoyuan(xiaoyuan2013@cqu.edu.cn)
收录类别SCI
WOS记录号WOS:000601619300010
语种英语