{"title":"在相图引导下通过晶界相消除提高立方相 GeTe 的热电性能","authors":"Fudong Zhang, Baopeng Ma, Yiyuan Luo, Lujun Zhu, Weishuai Wang, Yalin Shi, Beiquan Jia, Zhenhua Ge, Zupei Yang, Di Wu, Jiaqing He","doi":"10.1039/d4ee03090g","DOIUrl":null,"url":null,"abstract":"Eliminating the ferroelectric phase transition to obtain a cubic phase under ambient conditions is deemed an ultimate goal for p-type GeTe-based materials to be feasible for thermoelectric generator application at mid-temperature range. Alloying stoichiometric AgSbTe2 or non-stoichiometric Ag1-δSb1+δTe2+δ into GeTe can regulate its cubic-rhombohedral phase transition temperature well below 300 K; nevertheless, the existence of high-resistivity Ag8GeTe6 grain boundary phase impeded the further improvement of thermoelectric performance in both cases. In this work, as guided by the phase equilibrium diagram, we successfully eliminated the Ag8GeTe6 grain boundary phase by meticulously tailoring the alloying ratio x and regulating Ag/Sb ratio δ in (GeTe)x(Ag1-δSb1+δTe2+δ)x while retaining its cubic crystalline structure. Furthermore, the formation of Ge2Sb2Te5 imbedded in GeTe grains involved discrete van der Waals planar gaps which can further help reducing the lattice thermal conductivity. As a result, a peak figure of merit ZTmax ~2.0 at 673 K and average ZTave of ~1.5 at 323-773 K were obtained in our cubic-phase (GeTe)78(Ag0.77Sb1.23Te2.23)22, and the fabricated eight-pair thermoelectric power generator exhibited an outstanding conversion efficiency of ~ 6.3% with output power of ~1.32 W at a temperature difference of 480 K. This work demonstrated that eliminating the high-resistivity grain boundary phase is a facile way to realize enhanced thermoelectric performance, and could shed light on further researches on other thermoelectric materials.","PeriodicalId":72,"journal":{"name":"Energy & Environmental Science","volume":null,"pages":null},"PeriodicalIF":32.4000,"publicationDate":"2024-10-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":"{\"title\":\"Promoted thermoelectric performance in cubic-phase GeTe via grain-boundary phase elimination under phase diagram guidance\",\"authors\":\"Fudong Zhang, Baopeng Ma, Yiyuan Luo, Lujun Zhu, Weishuai Wang, Yalin Shi, Beiquan Jia, Zhenhua Ge, Zupei Yang, Di Wu, Jiaqing He\",\"doi\":\"10.1039/d4ee03090g\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"Eliminating the ferroelectric phase transition to obtain a cubic phase under ambient conditions is deemed an ultimate goal for p-type GeTe-based materials to be feasible for thermoelectric generator application at mid-temperature range. Alloying stoichiometric AgSbTe2 or non-stoichiometric Ag1-δSb1+δTe2+δ into GeTe can regulate its cubic-rhombohedral phase transition temperature well below 300 K; nevertheless, the existence of high-resistivity Ag8GeTe6 grain boundary phase impeded the further improvement of thermoelectric performance in both cases. In this work, as guided by the phase equilibrium diagram, we successfully eliminated the Ag8GeTe6 grain boundary phase by meticulously tailoring the alloying ratio x and regulating Ag/Sb ratio δ in (GeTe)x(Ag1-δSb1+δTe2+δ)x while retaining its cubic crystalline structure. Furthermore, the formation of Ge2Sb2Te5 imbedded in GeTe grains involved discrete van der Waals planar gaps which can further help reducing the lattice thermal conductivity. As a result, a peak figure of merit ZTmax ~2.0 at 673 K and average ZTave of ~1.5 at 323-773 K were obtained in our cubic-phase (GeTe)78(Ag0.77Sb1.23Te2.23)22, and the fabricated eight-pair thermoelectric power generator exhibited an outstanding conversion efficiency of ~ 6.3% with output power of ~1.32 W at a temperature difference of 480 K. This work demonstrated that eliminating the high-resistivity grain boundary phase is a facile way to realize enhanced thermoelectric performance, and could shed light on further researches on other thermoelectric materials.\",\"PeriodicalId\":72,\"journal\":{\"name\":\"Energy & Environmental Science\",\"volume\":null,\"pages\":null},\"PeriodicalIF\":32.4000,\"publicationDate\":\"2024-10-06\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"\",\"citationCount\":\"0\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"Energy & Environmental Science\",\"FirstCategoryId\":\"88\",\"ListUrlMain\":\"https://doi.org/10.1039/d4ee03090g\",\"RegionNum\":1,\"RegionCategory\":\"材料科学\",\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"\",\"PubModel\":\"\",\"JCR\":\"Q1\",\"JCRName\":\"CHEMISTRY, MULTIDISCIPLINARY\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"Energy & Environmental Science","FirstCategoryId":"88","ListUrlMain":"https://doi.org/10.1039/d4ee03090g","RegionNum":1,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q1","JCRName":"CHEMISTRY, MULTIDISCIPLINARY","Score":null,"Total":0}
Promoted thermoelectric performance in cubic-phase GeTe via grain-boundary phase elimination under phase diagram guidance
Eliminating the ferroelectric phase transition to obtain a cubic phase under ambient conditions is deemed an ultimate goal for p-type GeTe-based materials to be feasible for thermoelectric generator application at mid-temperature range. Alloying stoichiometric AgSbTe2 or non-stoichiometric Ag1-δSb1+δTe2+δ into GeTe can regulate its cubic-rhombohedral phase transition temperature well below 300 K; nevertheless, the existence of high-resistivity Ag8GeTe6 grain boundary phase impeded the further improvement of thermoelectric performance in both cases. In this work, as guided by the phase equilibrium diagram, we successfully eliminated the Ag8GeTe6 grain boundary phase by meticulously tailoring the alloying ratio x and regulating Ag/Sb ratio δ in (GeTe)x(Ag1-δSb1+δTe2+δ)x while retaining its cubic crystalline structure. Furthermore, the formation of Ge2Sb2Te5 imbedded in GeTe grains involved discrete van der Waals planar gaps which can further help reducing the lattice thermal conductivity. As a result, a peak figure of merit ZTmax ~2.0 at 673 K and average ZTave of ~1.5 at 323-773 K were obtained in our cubic-phase (GeTe)78(Ag0.77Sb1.23Te2.23)22, and the fabricated eight-pair thermoelectric power generator exhibited an outstanding conversion efficiency of ~ 6.3% with output power of ~1.32 W at a temperature difference of 480 K. This work demonstrated that eliminating the high-resistivity grain boundary phase is a facile way to realize enhanced thermoelectric performance, and could shed light on further researches on other thermoelectric materials.
期刊介绍:
Energy & Environmental Science, a peer-reviewed scientific journal, publishes original research and review articles covering interdisciplinary topics in the (bio)chemical and (bio)physical sciences, as well as chemical engineering disciplines. Published monthly by the Royal Society of Chemistry (RSC), a not-for-profit publisher, Energy & Environmental Science is recognized as a leading journal. It boasts an impressive impact factor of 8.500 as of 2009, ranking 8th among 140 journals in the category "Chemistry, Multidisciplinary," second among 71 journals in "Energy & Fuels," second among 128 journals in "Engineering, Chemical," and first among 181 scientific journals in "Environmental Sciences."
Energy & Environmental Science publishes various types of articles, including Research Papers (original scientific work), Review Articles, Perspectives, and Minireviews (feature review-type articles of broad interest), Communications (original scientific work of an urgent nature), Opinions (personal, often speculative viewpoints or hypotheses on current topics), and Analysis Articles (in-depth examination of energy-related issues).