| 1 | Carrier and microstructure tuning for improving the thermoelectric properties of Ag_(8)SnSe_(6)via introducing SnBr_(2)显示文摘The argyrodite compounds(2 A(12)/B X6 m n n^(m+)+--(Am+=Li^(+),Cu^(+),and Ag^(+);Bn^(+)=Ga^(3+),Si^(4+),Ge^(4+),Sn^(4+),P^(5+),and As^(5+);and X^(2−)=S^(2−),Se^(2−),or Te^(2−)))have attracted great attention as excellent thermoelectric(TE)materials due to their extremely low lattice thermal conductivity(κl).Among them,Ag_(8)SnSe_(6)-based TE materials have high potential for TE applications.However,the pristine Ag_(8)SnSe_(6)materials have low carrier concentration(<1017 cm^(−3)),resulting in low power factors.In this study,a hydrothermal method was used to synthesize Ag_(8)SnSe_(6)with high purity,and the introduction of SnBr_(2)into the pristine Ag_(8)SnSe_(6)powders has been used to simultaneously increase the power factor and decrease the thermal conductivity(κ).On the one hand,a portion of the Br−ions acted as electrons to increase the carrier concentration,increasing the power factor to a value of~698 mW·m^(−1)·K^(−2)at 736 K.On the other hand,some of the dislocations and nanoprecipitates(SnBr_(2))were generated,resulting in a decrease ofκl(~0.13 W·m^(−1)·K^(−1))at 578 K.As a result,the zT value reaches~1.42 at 735 K for the sample Ag8Sn1.03Se5.94Br0.06,nearly 30%enhancement in contrast with that of the pristine sample(~1.09).The strategy of synergistic manipulation of carrier concentration and microstructure by introducing halogen compounds could be applied to the argyrodite compounds to improve the TE properties. | Zhonghai YU Xiuxia WANG Chengyan LIU Yiran CHENG Zhongwei ZHANG Ruifan SI Xiaobo BAI Xiaokai HU Jie GAO Ying PENG Lei MIAO | 2022 | Journal of Advanced Ceramics2022，11，7： | 1 |
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