Investigation on the decomposition behavior of AgSbTe_(2)-based chalcogenides  

AgSbTe_(2)基热电材料的分解行为研究

作　　者：Yi Wu Pengfei Qiu Chuanyao Sun Xinjie Yuan Tingting Deng Xun Shi 吴一;仇鹏飞;孙传耀;苑鑫杰;邓婷婷;史迅

机构地区：[1]State Key Laboratory of High Performance Ceramics and Superfine Microstructure,Shanghai Institute of Ceramics,Chinese Academy of Sciences,Shanghai 200050,China [2]Center of Materials Science and Optoelectronics Engineering,University of Chinese Academy of Sciences,Beijing 100049,China [3]School of Chemistry and Materials Science,Hangzhou Institute for Advanced Study,University of Chinese Academy of Sciences,Hangzhou 310024,China

出　　处：《Science China Materials》2025年第3期912-919,共8页中国科学(材料科学)(英文版)

基　　金：supported by National Natural Science Foundation of China(grants 52122213 and 52203294);Shanghai Pilot Program for Basic Research-Chinese Academy of Science,Shanghai Branch(JCYJ-SHFY-2022-002).

摘　　要：Recently,AgSbTe_(2)-based ternary chalcogenides have attracted great attention in thermoelectric community due to their high figure-of-merits at the middle-temperature range,but their stability has raised huge controversy.Some literatures reported inconsistent and even contradictory results on their stability.In this work,taking Ag_(0.9)Sb_(1.1)Te_(2.1) as an example,we systematically investigate its decomposition behavior to explore the stability of AgSbTe_(2)-based chalcogenides.Obvious decomposition is observed for Ag_(0.9)Sb_(1.1)Te_(2.1) between 473-643 K,but the decomposition rate does not monotonously vary with increasing temperature.The rapidest decomposition rate occurs around 573 K.Ag_(0.9)Sb_(1.1)Te_(2.1) does not directly decompose into Ag_(2)Te and Sb_(2)Te_(3).A layered Ag-Sb-Te ternary phase with diverse stacking units exists as the intermediate decomposition product and the transformation from it to the final Sb_(2)Te_(3) needs very long duration.In addition,the decomposition products can regenerate into the pure AgSbTe_(2)-based cubic phase above the decomposition temperature range.Finally,a qualitative Time-Temperature-Transformation diagram is plotted for Ag_(0.9)Sb_(1.1)Te_(2.1),which can intuitively illustrate its thermodynamic-and kinetic-controlled decomposition behavior.This work might be able to end the long-term controversy on the stability of AgSbTe_(2)-based chalcogenides and guide the development of stable compounds in the future.近年来,AgSbTe_(2)基三元硫族化合物因其在中温区的高热电性能获得了热电领域的广泛关注.但是,AgSbTe_(2)基三元硫族化合物稳定性引起了巨大争议,之前文献报道了不一致甚至彼此矛盾的结果.本文以Ag_(0.9)Sb_(1.1)Te_(2.1)为例,系统研究了其分解行为,探讨了AgSbTe_(2)基硫族化合物的稳定性.研究发现,Ag_(0.9)Sb_(1.1)Te_(2.1)在473-643 K温度范围内有明显的分解,但分解速率随温度的升高表现出非单调变化,在573 K附近达到最大值.Ag_(0.9)Sb_(1.1)Te_(2.1)并非直接分解为Ag_(2)Te和Sb_(2)Te_(3),而是先形成Ag_(2)Te和一种具有不同堆积单元的Ag-Sb-Te三元层状化合物.该三元层状化合物转变为最终的分解产物Sb_(2)Te_(3)非常缓慢.此外,在分解温度范围以上,分解产物可以快速重新反应生成Ag_(0.9)Sb_(1.1)Te_(2.1)单相.最后,本工作绘制了Ag_(0.9)Sb_(1.1)Te_(2.1)的时间温度转变图,可直观地反映其热力学和动力学控制的分解行为.本工作有望结束长期以来关于AgSbTe_(2)基硫族化合物稳定性的争议,并指导今后该类材料稳定性的研究.

关 键 词：AgSbTe_(2) STABILITY TTT diagram THERMOELECTRIC 

分 类 号：TG1[金属学及工艺—金属学]