1
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Jana SS, Maiti T. Designing rare earth-free high entropy oxides with a tungsten bronze structure for thermoelectric applications. MATERIALS HORIZONS 2023; 10:1848-1855. [PMID: 36880636 DOI: 10.1039/d2mh01488b] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
In recent years, forming high entropy oxides has emerged as one of the promising approaches to designing oxide thermoelectrics. Entropy engineering is an excellent strategy to improve thermoelectric performance by minimizing the thermal conductivity arising from enhanced multi-phonon scattering. In the present work, we have successfully synthesized a rare-earth-free single phase solid solution of novel high entropy niobate (Sr0.2Ba0.2Li0.2K0.2Na0.2)Nb2O6, with a tungsten bronze structure. This is the first report on the thermoelectric properties of high entropy tungsten bronze-type structures. We have obtained a maximum Seebeck coefficient of -370 μV K-1 at 1150 K, which is the highest among tungsten bronze-type oxide thermoelectrics. The minimum thermal conductivity of 0.8 W m-1 K-1 is obtained at 330 K, which is so far the lowest reported value among rare-earth-free high entropy oxide thermoelectrics. This synergistic combination of large Seebeck and record low thermal conductivity gives rise to a maximum ZT of 0.23 which is so far the highest among rare-earth free high entropy oxide-based thermoelectrics.
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Affiliation(s)
- Subhra Sourav Jana
- Plasmonics and Perovskites Laboratory, Department of Materials Science and Engineering, IIT, Kanpur, UP 208016, India.
| | - Tanmoy Maiti
- Plasmonics and Perovskites Laboratory, Department of Materials Science and Engineering, IIT, Kanpur, UP 208016, India.
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2
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Zhu Y, Azough F, Liu X, Zhong X, Zhao M, Margaronis K, Kar-Narayan S, Kinloch I, Lewis DJ, Freer R. Precursor-Led Grain Boundary Engineering for Superior Thermoelectric Performance in Niobium Strontium Titanate. ACS APPLIED MATERIALS & INTERFACES 2023; 15:13097-13107. [PMID: 36854123 PMCID: PMC10020962 DOI: 10.1021/acsami.2c22712] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/19/2022] [Accepted: 02/16/2023] [Indexed: 06/18/2023]
Abstract
We present a novel method to significantly enhance the thermoelectric performance of ceramics in the model system SrTi0.85Nb0.15O3 through the use of the precursor ammonium tetrathiomolybdate (0.5-2% w/w additions). After sintering the precursor-infused green body at 1700 K for 24 h in 5% H2/Ar, single-crystal-like electron transport behavior developed with electrical conductivity reaching ∼3000 S/cm at ∼300 K, almost a magnitude higher than that in the control sample. During processing, the precursor transformed into MoS2, then into MoOx, and finally into Mo particles. This limited grain growth promoted secondary phase generation but importantly helped to reduce the grain boundary barriers. Samples prepared with additions of the precursor exhibited vastly increased electrical conductivity, without significant impact on Seebeck coefficients giving rise to high power factor values of 1760 μW/mK2 at ∼300 K and a maximum thermoelectric figure-of-merit zT of 0.24 at 823 K. This processing strategy provides a simple method to achieve high charge mobility in polycrystalline titanate and related materials and with the potential to create "phonon-glass-electron-crystal" oxide thermoelectric materials.
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Affiliation(s)
- Yibing Zhu
- Department
of Materials, School of Natural Sciences, University of Manchester, Manchester M13 9PL, U.K.
| | - Feridoon Azough
- Department
of Materials, School of Natural Sciences, University of Manchester, Manchester M13 9PL, U.K.
| | - Xiaodong Liu
- Department
of Materials, School of Natural Sciences, University of Manchester, Manchester M13 9PL, U.K.
| | - Xiangli Zhong
- Department
of Materials, School of Natural Sciences, University of Manchester, Manchester M13 9PL, U.K.
| | - Minghao Zhao
- Department
of Chemistry, School of Natural Sciences, University of Manchester, Manchester M13 9PL, U.K.
| | - Kalliope Margaronis
- Department
of Materials Science & Metallurgy, University
of Cambridge, 27 Charles Babbage Road, Cambridge CB3 0FS, U.K.
| | - Sohini Kar-Narayan
- Department
of Materials Science & Metallurgy, University
of Cambridge, 27 Charles Babbage Road, Cambridge CB3 0FS, U.K.
| | - Ian Kinloch
- Department
of Materials, School of Natural Sciences, University of Manchester, Manchester M13 9PL, U.K.
- Henry
Royce Institute and National Graphene Institute, University of Manchester, Oxford Road, Manchester M13 9PL, U.K.
| | - David J. Lewis
- Department
of Materials, School of Natural Sciences, University of Manchester, Manchester M13 9PL, U.K.
| | - Robert Freer
- Department
of Materials, School of Natural Sciences, University of Manchester, Manchester M13 9PL, U.K.
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3
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Ekren D, Cao J, Azough F, Kepaptsoglou D, Ramasse Q, Kinloch IA, Freer R. Controlling the Thermoelectric Behavior of La-Doped SrTiO 3 through Processing and Addition of Graphene Oxide. ACS APPLIED MATERIALS & INTERFACES 2022; 14:53711-53723. [PMID: 36413504 PMCID: PMC9743083 DOI: 10.1021/acsami.2c14408] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/10/2022] [Accepted: 11/01/2022] [Indexed: 06/16/2023]
Abstract
The addition of graphene has been reported as a potential route to enhance the thermoelectric performance of SrTiO3. However, the interplay between processing parameters and graphene addition complicates understanding this enhancement. Herein, we examine the effects of processing parameters and graphene addition on the thermoelectric performance of La-doped SrTiO3 (LSTO). Briefly, two types of graphene oxide (GO) at different oxidation degrees were used, while the LSTO pellets were densified under two conditions with different reducing strengths (with/without using oxygen-scavenging carbon powder bed muffling). Raman imaging of the LSTO green body and sintered pellets suggests that the added GO sacrificially reacts with the lattice oxygen, which creates more oxygen vacancies and improves electrical conductivity regardless of the processing conditions. The addition of mildly oxidized electrochemical GO (EGO) yields better performance than the conventional heavily oxidized chemical GO (CGO). Moreover, we found that muffling the green body with an oxygen-scavenging carbon powder bed during sintering is vital to achieving a single-crystal-like temperature dependence of electrical conductivity, implying that a highly reducing environment is critical for eliminating the grain boundary barriers. Combining 1.0 wt % EGO addition with a highly reducing environment leads to the highest electrical conductivity of 2395 S cm-1 and power factor of 2525μW m-1 K-2 at 300 K, with an improved average zT value across the operating temperature range of 300-867 K. STEM-EELS maps of the optimized sample show a pronounced depletion of Sr and evident deficiency of O and La at the grain boundary region. Theoretical modeling using a two-phase model implies that the addition of GO can effectively improve carrier mobility in the grain boundary phase. This work provides guidance for the development of high-performance thermoelectric ceramic oxides.
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Affiliation(s)
- Dursun Ekren
- Department
of Materials, University of Manchester, Oxford Road, ManchesterM13 9PL, U.K.
- Department
of Metallurgical and Materials Engineering, Iskenderun Technical University, İskenderun31200, Hatay, Turkey
| | - Jianyun Cao
- Department
of Materials, University of Manchester, Oxford Road, ManchesterM13 9PL, U.K.
- Key
Laboratory of LCR Materials and Devices of Yunnan Province, School
of Materials Science and Energy, Yunnan
University, Kunming650500, China
| | - Feridoon Azough
- Department
of Materials, University of Manchester, Oxford Road, ManchesterM13 9PL, U.K.
| | - Demie Kepaptsoglou
- SuperSTEM
Laboratory, SciTech Daresbury Campus, Daresbury, WarringtonWA4
4AD, U.K.
- Department
of Physics, University of York, YorkYO10 5DD, U.K.
| | - Quentin Ramasse
- SuperSTEM
Laboratory, SciTech Daresbury Campus, Daresbury, WarringtonWA4
4AD, U.K.
- School of
Chemical and Process Engineering, University
of Leeds, LeedsLS2 9JT, U.K.
| | - Ian A. Kinloch
- Department
of Materials, University of Manchester, Oxford Road, ManchesterM13 9PL, U.K.
- Henry
Royce Institute and National Graphene Institute, University of Manchester, Oxford Road, ManchesterM13 9PL, U.K.
| | - Robert Freer
- Department
of Materials, University of Manchester, Oxford Road, ManchesterM13 9PL, U.K.
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4
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Lamhani M, Chchiyai Z, Elomrani A, Manoun B, Hasnaoui A. The effect of Sr substitution on the structural and physical properties of manganite perovskites Ca 1-xSr xMnO 3-δ (0 ≤ x ≤ 1). Phys Chem Chem Phys 2022; 24:19414-19431. [PMID: 35920833 DOI: 10.1039/d2cp01096h] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Calcium manganite (CaMnO3-δ) has been extensively utilized in many applications due to its unique physical and chemical properties. In this study, the effect of Sr-substitution at the Ca-site on the structural, magnetic, electronic and electrical properties of CaMnO3 manganite perovskites is investigated in detail. The perovskite compounds Ca1-xSrxMnO3-δ (x = 0, 0.25, 0.5, 0.75 and 1) were synthesized through the sol-gel method at 1200 °C. From the patterns of X-ray diffraction, it was observed that all of the synthesized compounds show a pure perovskite phase at room temperature. The refinement results of the perovskite series suggest that a structural transformation from an orthorhombic (Pnma) to a hexagonal (P63/mmc) system occurred for 0.50 < x ≤ 0.75. We note however that the sample with the composition x = 0.50 showed a phase mixture of orthorhombic (Pnma) and hexagonal (P63/mmc). Based on DFT calculations, we have demonstrated the energetic stability of all compounds by negative formation energy and confirmed the semiconductor behavior by the presence of a band gap. The change in the band gap value with the Sr content suggests the potential tuning of the electronic behavior of CaMnO3-SrMnO3 solid solution. Furthermore, as the temperature increases from 300 to 1000 K, the electrical resistivity exhibits a reduction while the Seebeck coefficient (S) shows an augmentation. The negative values of S indicated the n-type-semiconductor nature of all compounds. The obtained values of the activation energy from thermal evolution of resistivity suggested that the electrical transport behavior of all the compounds followed the mechanism of small polaron hopping. Power factor is greatly affected by the Sr amount and reached a maximum value at x = 0.50. Overall, introducing Sr into the CaMnO3-δ matrix improved the power factor and reduced electrical resistivity. According to the obtained results, the studied manganite perovskites could be proposed as suitable materials for photocatalytic and thermoelectric applications.
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Affiliation(s)
- Mohammed Lamhani
- Sultane Moulay Slimane University of Beni Mellal, FPK, Laboratory of Materials, Mathematics and Environment Sciences (LS2ME), 25000, Khouribga, Morocco.
| | - Zakaria Chchiyai
- Hassan First University of Settat, FST, Rayonnement-Matière et Instrumentation, S3M, 26000, Settat, Morocco.,University Mohammed VI Polytechnic, Materials Science and Nano-engineering Department, Ben Guerir, Morocco
| | - Abdelali Elomrani
- Sultane Moulay Slimane University of Beni Mellal, FPK, Laboratory of Materials, Mathematics and Environment Sciences (LS2ME), 25000, Khouribga, Morocco.
| | - Bouchaib Manoun
- Hassan First University of Settat, FST, Rayonnement-Matière et Instrumentation, S3M, 26000, Settat, Morocco.,University Mohammed VI Polytechnic, Materials Science and Nano-engineering Department, Ben Guerir, Morocco
| | - Abdellatif Hasnaoui
- Sultane Moulay Slimane University of Beni Mellal, FPK, Laboratory of Materials, Mathematics and Environment Sciences (LS2ME), 25000, Khouribga, Morocco.
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5
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Zhang P, Qin M, Lou Z, Cao S, Gong L, Xu J, Reece MJ, Yan H, Dashevsky Z, Gao F. Grain orientation evolution and multi-scale interfaces enhanced thermoelectric properties of textured Sr0.9La0.1TiO3 based ceramics. Ann Ital Chir 2022. [DOI: 10.1016/j.jeurceramsoc.2022.08.009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022]
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6
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Ma Z, Qi Y, Bi X, Liu XD, Li X, Li JG, Sun X. The effect of annealing in carbon powders on the anisotropy of the thermoelectric properties of SrTiO 3−δ single crystals on the (001) crystal plane. CrystEngComm 2022. [DOI: 10.1039/d2ce00423b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The anisotropy of the thermoelectric properties of SrTiO3 on the (001) crystal plane is investigated by a combination of first-principles calculations and experimental results.
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Affiliation(s)
- Zhixin Ma
- Key Laboratory for Anisotropy and Texture of Materials (Ministry of Education), Northeastern University, Shenyang, Liaoning, 110819, PR China
- Foshan Graduate School of Northeastern University, Foshan, Guangdong, PR China
| | - Yang Qi
- Key Laboratory for Anisotropy and Texture of Materials (Ministry of Education), Northeastern University, Shenyang, Liaoning, 110819, PR China
| | - Xiaoguo Bi
- School of New Energy, Shenyang Institute of Engineering, Shenyang, Liaoning, 110136, PR China
| | - Xu-dong Liu
- College of Environmental and Chemical Engineering, Dalian University, Dalian, Liaoning, 116622, PR China
| | - Xiaodong Li
- Key Laboratory for Anisotropy and Texture of Materials (Ministry of Education), Northeastern University, Shenyang, Liaoning, 110819, PR China
| | - Ji-guang Li
- Research Center for Functional Materials, National Institute for Materials Science, Tsukuba, Ibaraki, 305-0044, Japan
| | - Xudong Sun
- Foshan Graduate School of Northeastern University, Foshan, Guangdong, PR China
- State Key Laboratory of Rolling and Automation, Northeastern University, Shenyang, Liaoning, 110819, PR China
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7
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Singh SP, Kanas N, Desissa TD, Johnsson M, Einarsrud MA, Norby T, Wiik K. Thermoelectric properties of A-site deficient La-doped SrTiO3 at 100–900 °C under reducing conditions. Ann Ital Chir 2020. [DOI: 10.1016/j.jeurceramsoc.2019.09.024] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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8
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Bakhshi H, Sarraf-Mamoory R, Yourdkhani A, AbdelNabi AA, Mozharivskyj Y. Highly dense Sr 0.95Sm 0.0125Dy 0.0125□ 0.025Ti 0.90Nb 0.10O 3±δ/ZrO 2 composite preparation directly through spark plasma sintering and its thermoelectric properties. Dalton Trans 2020; 49:17-22. [PMID: 31799569 DOI: 10.1039/c9dt03934a] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The Sr0.95Sm0.0125Dy0.0125□0.025Ti0.90Nb0.10O3±δ/ZrO2 composite was directly prepared through spark plasma sintering. This approach limited the grain growth and facilitated the achievement of a narrow grain size distribution due to fast sintering and ZrO2 effects. Thermal conductivity declined to 1.68 W m-1 K-1, which is the lowest among the reported values for micro-polycrystalline SrTiO3-based structures.
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Affiliation(s)
- Hamed Bakhshi
- Department of Materials Engineering, Tarbiat Modares University, Tehran, Iran.
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9
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Rubi K, Mahendiran R. Large thermoelectric response of B-site doped ferroelectrics: Ba0.7Eu0.3Ti1-Nb O3 (x = 0 to 0.1). J SOLID STATE CHEM 2020. [DOI: 10.1016/j.jssc.2019.121050] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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10
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Virtudazo RVR, Srinivasan B, Guo Q, Wu R, Takei T, Shimasaki Y, Wada H, Kuroda K, Bernik S, Mori T. Improvement in the thermoelectric properties of porous networked Al-doped ZnO nanostructured materials synthesized via an alternative interfacial reaction and low-pressure SPS processing. Inorg Chem Front 2020. [DOI: 10.1039/d0qi00888e] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
This work presents a novel, simpler and faster bottom-up approach to produce relatively high performance thermoelectric Al-doped ZnO ceramics from nanopowders produced by interfacial reaction followed by consolidation with Spark Plasma Sintering.
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11
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Azough F, Gholinia A, Alvarez-Ruiz DT, Duran E, Kepaptsoglou DM, Eggeman AS, Ramasse QM, Freer R. Self-Nanostructuring in SrTiO 3: A Novel Strategy for Enhancement of Thermoelectric Response in Oxides. ACS APPLIED MATERIALS & INTERFACES 2019; 11:32833-32843. [PMID: 31419381 DOI: 10.1021/acsami.9b06483] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Nanostructuring is recognized as an efficient route for enhancing thermoelectric response. Here, we report a new synthesis strategy for nanostructuring oxide ceramics and demonstrate its effectiveness on an important n-type thermoelectric SrTiO3. Ceramics of Sr0.9La0.1TiO3 with additions of B2O3 were synthesized by the mixed oxide route. Samples were sintered in air followed by annealing in a reducing atmosphere. Crystallographic data from X-ray and electron diffraction showed Pm3̅m cubic symmetry for all the samples. High-resolution transmission electron microscopy (HRTEM) showed the formation of a core-shell type structure within the grains for the annealed ceramics. The cores contain nanosize features comprising pairs of nanosize voids and particles; the feature sizes depend on annealing time. Atomic-resolution, high-angle annular-dark-field imaging and electron energy loss spectroscopy in the scanning transmission electron microscopy (STEM-HAADF-EELS) showed the particles to be rich in Ti and the areas around the voids to contain high concentrations of Ti3+. Additionally, dislocations were observed, with significantly higher densities in the shell areas. The observed dislocations are combined (100) and (110) edge dislocations. The major impact of the core-shell type microstructures, with nanosize inclusions, is the reduction of the thermal conductivity. Sr0.9La0.1TiO3 ceramics containing grain boundary shells of size ≈ 1 μm and inclusions in the core of 60-80 nm exhibit a peak power factor of 1600 μW/m·K2 at 540 K; at 1000 K, they exhibit a low thermal conductivity (2.75 W/m·K) and a power factor of 1050 μW/m·K2 leading to a high of ZT of 0.39 ± 0.03. This is the highest ZT reported so far for Sr0.9La0.1TiO3 based-compositions. This nanostructuring strategy should be readily applicable to other functional oxides.
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Affiliation(s)
- Feridoon Azough
- School of Materials , University of Manchester , Manchester , M13 9PL , U.K
| | - Ali Gholinia
- School of Materials , University of Manchester , Manchester , M13 9PL , U.K
| | | | - Ercin Duran
- School of Materials , University of Manchester , Manchester , M13 9PL , U.K
| | - Demie M Kepaptsoglou
- SuperSTEM Laboratory , STFC Daresbury Campus , Daresbury WA4 4AD , U.K
- Jeol Nanocentre and Department of Physics , University of York , Heslington, York YO10 5DD , U.K
| | | | - Quentin M Ramasse
- SuperSTEM Laboratory , STFC Daresbury Campus , Daresbury WA4 4AD , U.K
- School of Chemical and Process Engineering and School of Physics , University of Leeds , Leeds LS2 9JT , U.K
| | - Robert Freer
- School of Materials , University of Manchester , Manchester , M13 9PL , U.K
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12
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Sotelo A, Torres MA, Madre MA, Diez JC. Influence of Ag on the Properties of Ca 0.9Yb 0.1MnO₃ Sintered Ceramics. MATERIALS 2018; 11:ma11122503. [PMID: 30544874 PMCID: PMC6317020 DOI: 10.3390/ma11122503] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/14/2018] [Revised: 11/29/2018] [Accepted: 12/05/2018] [Indexed: 11/16/2022]
Abstract
In this study, Ca0.9Yb0.1MnO3 + x wt.% Ag (with x = 0, 1, 3, 5, and 10) thermoelectric materials were prepared via the classical ceramic method. In spite of the very high sintering temperature (1300 °C), no significant Ag losses were observed following this process. Moreover, Ag addition enhanced cation mobility during sintering due to the formation of a liquid phase. Microstructurally, it was found that Ag decreases porosity; this was confirmed by density measurements. Ag was also found to promote the formation of a Ca2Mn2O5 secondary phase. Despite the presence of this secondary phase, samples with Ag displayed lower electrical resistivity than Ag-free ones, without a drastic decrease in the absolute Seebeck coefficient. The highest thermoelectric performances, which were determined by power factor, were obtained in 1 wt.% Ag samples. These maximum values are slightly higher than the best of those reported in the literature for sintered materials with similar compositions, with the additional advantage of their being obtained using a much shorter sintering procedure.
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Affiliation(s)
- Andrés Sotelo
- Instituto de Ciencia de Materiales de Aragón (CSIC-Universidad de Zaragoza), C/María de Luna, 3, 50018 Zaragoza, Spain.
| | - Miguel A Torres
- Instituto de Ciencia de Materiales de Aragón (CSIC-Universidad de Zaragoza), C/María de Luna, 3, 50018 Zaragoza, Spain.
| | - María A Madre
- Instituto de Ciencia de Materiales de Aragón (CSIC-Universidad de Zaragoza), C/María de Luna, 3, 50018 Zaragoza, Spain.
| | - Juan C Diez
- Instituto de Ciencia de Materiales de Aragón (CSIC-Universidad de Zaragoza), C/María de Luna, 3, 50018 Zaragoza, Spain.
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13
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Labégorre JB, Lebedev OI, Bourgès C, Rečnik A, Košir M, Bernik S, Maignan A, Le Mercier T, Pautrot-d'Alençon L, Guilmeau E. Phonon Scattering and Electron Doping by 2D Structural Defects in In/ZnO. ACS APPLIED MATERIALS & INTERFACES 2018; 10:6415-6423. [PMID: 29359559 DOI: 10.1021/acsami.7b19489] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
In/ZnO bulk compounds have been synthesized using a simple solid-state process. In this study, both the structural features and thermoelectric properties of the Zn1-xInxO series with ultralow indium content (0 ≤ x ≤ 0.02) have been studied. High-angle annular dark-field scanning transmission electron microscopy analyses highlight that indium has the ability to create multiple basal plane and pyramidal defects that produce ZnO domains with inverted polarity starting from dopant concentrations as low as 0.25 atom %. Interestingly, the formation of parallel inversion boundaries consisting of InO6 octahedra in the ZnO4 tetrahedra matrix is responsible for phonon scattering while increasing electrical conductivity, thereby enhancing the thermoelectric properties. This effect of multiple extended two-dimensional defects on the thermoelectric properties of ZnO is reported for the first time with such low indium doping. On the chemistry side, the present results point toward a lack of In solubility in the ZnO structure. Moreover, this study is a step forward to the synthesis of other thermoelectric compounds where dopant-induced planar defects in bulk transition metal compounds have the potential to enhance both phonon scattering and electronic conductivity.
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Affiliation(s)
- Jean-Baptiste Labégorre
- Laboratoire CRISMAT, UMR-CNRS 6508, ENSICAEN, UNICAEN, Normandie Université , 6 Boulevard du Maréchal Juin, 14050 Caen Cedex 04, France
| | - Oleg I Lebedev
- Laboratoire CRISMAT, UMR-CNRS 6508, ENSICAEN, UNICAEN, Normandie Université , 6 Boulevard du Maréchal Juin, 14050 Caen Cedex 04, France
| | - Cédric Bourgès
- Laboratoire CRISMAT, UMR-CNRS 6508, ENSICAEN, UNICAEN, Normandie Université , 6 Boulevard du Maréchal Juin, 14050 Caen Cedex 04, France
| | - Aleksander Rečnik
- Department for Nanostructured Materials, Jožef Stefan Institute , Jamova cesta 39, 1000 Ljubljana, Slovenia
| | - Mateja Košir
- Department for Nanostructured Materials, Jožef Stefan Institute , Jamova cesta 39, 1000 Ljubljana, Slovenia
| | - Slavko Bernik
- Department for Nanostructured Materials, Jožef Stefan Institute , Jamova cesta 39, 1000 Ljubljana, Slovenia
| | - Antoine Maignan
- Laboratoire CRISMAT, UMR-CNRS 6508, ENSICAEN, UNICAEN, Normandie Université , 6 Boulevard du Maréchal Juin, 14050 Caen Cedex 04, France
| | - Thierry Le Mercier
- Solvay, Centre de Recherches d'Aubervilliers , 52 rue de la Haie-Coq, 93308 Aubervilliers Cedex, France
| | | | - Emmanuel Guilmeau
- Laboratoire CRISMAT, UMR-CNRS 6508, ENSICAEN, UNICAEN, Normandie Université , 6 Boulevard du Maréchal Juin, 14050 Caen Cedex 04, France
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14
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Kepaptsoglou D, Baran JD, Azough F, Ekren D, Srivastava D, Molinari M, Parker SC, Ramasse QM, Freer R. Prospects for Engineering Thermoelectric Properties in La 1/3NbO 3 Ceramics Revealed via Atomic-Level Characterization and Modeling. Inorg Chem 2017; 57:45-55. [PMID: 29257680 DOI: 10.1021/acs.inorgchem.7b01584] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
A combination of experimental and computational techniques has been employed to explore the crystal structure and thermoelectric properties of A-site-deficient perovskite La1/3NbO3 ceramics. Crystallographic data from X-ray and electron diffraction confirmed that the room temperature structure is orthorhombic with Cmmm as a space group. Atomically resolved imaging and analysis showed that there are two distinct A sites: one is occupied with La and vacancies, and the second site is fully unoccupied. The diffuse superstructure reflections observed through diffraction techniques are shown to originate from La vacancy ordering. La1/3NbO3 ceramics sintered in air showed promising high-temperature thermoelectric properties with a high Seebeck coefficient of S1 = -650 to -700 μV/K and a low and temperature-stable thermal conductivity of k = 2-2.2 W/m·K in the temperature range of 300-1000 K. First-principles electronic structure calculations are used to link the temperature dependence of the Seebeck coefficient measured experimentally to the evolution of the density of states with temperature and indicate possible avenues for further optimization through electron doping and control of the A-site occupancies. Moreover, lattice thermal conductivity calculations give insights into the dependence of the thermal conductivity on specific crystallographic directions of the material, which could be exploited via nanostructuring to create high-efficiency compound thermoelectrics.
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Affiliation(s)
| | - Jakub D Baran
- Department of Chemistry, University of Bath , Claverton Down, Bath BA2 7AY, U.K
| | - Feridoon Azough
- School of Materials, University of Manchester , Manchester M13 9PL, U.K
| | - Dursun Ekren
- School of Materials, University of Manchester , Manchester M13 9PL, U.K
| | | | - Marco Molinari
- Department of Chemistry, University of Bath , Claverton Down, Bath BA2 7AY, U.K.,Department of Chemistry, University of Huddersfield , Huddersfield HD1 3DH, U.K
| | - Stephen C Parker
- Department of Chemistry, University of Bath , Claverton Down, Bath BA2 7AY, U.K
| | - Quentin M Ramasse
- SuperSTEM Laboratory, SciTech Daresbury Campus , Daresbury WA4 4AD, U.K
| | - Robert Freer
- School of Materials, University of Manchester , Manchester M13 9PL, U.K
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15
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Azough F, Jackson SS, Ekren D, Freer R, Molinari M, Yeandel SR, Panchmatia PM, Parker SC, Maldonado DH, Kepaptsoglou DM, Ramasse QM. Concurrent La and A-Site Vacancy Doping Modulates the Thermoelectric Response of SrTiO 3: Experimental and Computational Evidence. ACS APPLIED MATERIALS & INTERFACES 2017; 9:41988-42000. [PMID: 29134804 DOI: 10.1021/acsami.7b14231] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
To help understand the factors controlling the performance of one of the most promising n-type oxide thermoelectric SrTiO3, we need to explore structural control at the atomic level. In Sr1-xLa2x/3TiO3 ceramics (0.0 ≤ x ≤ 0.9), we determined that the thermal conductivity can be reduced and controlled through an interplay of La-substitution and A-site vacancies and the formation of a layered structure. The decrease in thermal conductivity with La and A-site vacancy substitution dominates the trend in the overall thermoelectric response. The maximum dimensionless figure of merit is 0.27 at 1070 K for composition x = 0.50 where half of the A-sites are occupied with La and vacancies. Atomic resolution Z-contrast imaging and atomic scale chemical analysis show that as the La content increases, A-site vacancies initially distribute randomly (x < 0.3), then cluster (x ≈ 0.5), and finally form layers (x = 0.9). The layering is accompanied by a structural phase transformation from cubic to orthorhombic and the formation of 90° rotational twins and antiphase boundaries, leading to the formation of localized supercells. The distribution of La and A-site vacancies contributes to a nonuniform distribution of atomic scale features. This combination induces temperature stable behavior in the material and reduces thermal conductivity, an important route to enhancement of the thermoelectric performance. A computational study confirmed that the thermal conductivity of SrTiO3 is lowered by the introduction of La and A-site vacancies as shown by the experiments. The modeling supports that a critical mass of A-site vacancies is needed to reduce thermal conductivity and that the arrangement of La, Sr, and A-site vacancies has a significant impact on thermal conductivity only at high La concentration.
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Affiliation(s)
- Feridoon Azough
- School of Materials, University of Manchester , Manchester M13 9PL, U.K
| | - Samuel S Jackson
- School of Materials, University of Manchester , Manchester M13 9PL, U.K
| | - Dursun Ekren
- School of Materials, University of Manchester , Manchester M13 9PL, U.K
| | - Robert Freer
- School of Materials, University of Manchester , Manchester M13 9PL, U.K
| | - Marco Molinari
- Department of Chemistry, University of Bath , Claverton Down, Bath BA2 7AY, U.K
- Department of Chemistry, University of Huddersfield , Queensgate, Huddersfield HD1 3DH, U.K
| | - Stephen R Yeandel
- Department of Chemistry, University of Bath , Claverton Down, Bath BA2 7AY, U.K
- Department of Chemistry, Loughborough University , Epinal Way, Loughborough LE11 3TU, U.K
| | - Pooja M Panchmatia
- Department of Chemistry, Loughborough University , Epinal Way, Loughborough LE11 3TU, U.K
| | - Stephen C Parker
- Department of Chemistry, University of Bath , Claverton Down, Bath BA2 7AY, U.K
| | | | - Demie M Kepaptsoglou
- SuperSTEM Laboratory , SciTech Daresbury Campus, Keckwick Lane, Warrington WA4 4AD, U.K
| | - Quentin M Ramasse
- SuperSTEM Laboratory , SciTech Daresbury Campus, Keckwick Lane, Warrington WA4 4AD, U.K
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16
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Eom K, Choi E, Choi M, Han S, Zhou H, Lee J. Oxygen Vacancy Linear Clustering in a Perovskite Oxide. J Phys Chem Lett 2017; 8:3500-3505. [PMID: 28707469 DOI: 10.1021/acs.jpclett.7b01348] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Oxygen vacancies have been implicitly assumed isolated ones, and understanding oxide materials possibly containing oxygen vacancies remains elusive within the scheme of the isolated vacancies, although the oxygen vacancies have been playing a decisive role in oxide materials. Here, we report the presence of oxygen vacancy linear clusters and their orientation along a specific crystallographic direction in SrTiO3, a representative of a perovskite oxide. The presence of the linear clusters and associated electron localization was revealed by an electronic structure represented in the increase in the Ti2+ valence state or corresponding Ti 3d2 electronic configuration along with divacancy cluster model analysis and transport measurement. The orientation of the linear clusters along the [001] direction in perovskite SrTiO3 was verified by further X-ray diffuse scattering analysis. Because SrTiO3 is an archetypical perovskite oxide, the vacancy linear clustering with the specific aligned direction and electron localization can be extended to a wide variety of the perovskite oxides.
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Affiliation(s)
- Kitae Eom
- School of Advanced Materials Science and Engineering, Sungkyunkwan University , Suwon 16419, Korea
| | - Euiyoung Choi
- School of Advanced Materials Science and Engineering, Sungkyunkwan University , Suwon 16419, Korea
| | - Minsu Choi
- School of Advanced Materials Science and Engineering, Sungkyunkwan University , Suwon 16419, Korea
| | - Seungwu Han
- Department of Materials Science and Engineering, Seoul National University , Seoul 08826, Korea
| | - Hua Zhou
- Advanced Photon Source, Argonne National Laboratory , Argonne, Illinois 60439, United States
| | - Jaichan Lee
- School of Advanced Materials Science and Engineering, Sungkyunkwan University , Suwon 16419, Korea
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17
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Nasani N, Oliveira Rocha CM, Kovalevsky AV, Otero Irurueta G, Populoh S, Thiel P, Weidenkaff A, Neto da Silva F, Fagg DP. Exploring the Thermoelectric Performance of BaGd 2NiO 5 Haldane Gap Materials. Inorg Chem 2017; 56:2354-2362. [PMID: 28177255 DOI: 10.1021/acs.inorgchem.7b00049] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
One-dimensional Haldane gap materials, such as the rare earth barium chain nickelates, have received great interest due to their vibrant one-dimensional spin antiferromagnetic character and unique structure. Herein we report how these 1D structural features can also be highly beneficial for thermoelectric applications by analysis of the system CaxBaGd2-xNiO5 0 ≤ x ≤ 0.25. Attractive Seebeck coefficients of 140-280 μV K-1 at 350-1300 K are retained even at high acceptor-substitution levels, provided by the interplay of low dimensionality and electronic correlations. Furthermore, the highly anisotropic crystal structure of Haldane gap materials allows very low thermal conductivities, reaching only 1.5 W m-1 K-1 at temperatures above 1000 K, one of the lowest values currently documented for prospective oxide thermoelectrics. Although calcium substitution in BaGd2NiO5 increases the electrical conductivity up to 5-6 S cm-1 at 1150 K < T < 1300 K, this level remains insufficient for thermoelectric applications. Hence, the combination of highly promising Seebeck coefficients and low thermal conductivities offered by this 1D material type underscores a potential new structure type for thermoelectric materials, where the main challenge will be to engineer the electronic band structure and, probably, microstructural features to further enhance the mobility of the charge carriers.
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Affiliation(s)
- Narendar Nasani
- Centre for Mechanical Technology and Automation (TEMA), Department of Mechanical Engineering, University of Aveiro , 3810-193 Aveiro, Portugal
| | - Carlos Miguel Oliveira Rocha
- Centre for Mechanical Technology and Automation (TEMA), Department of Mechanical Engineering, University of Aveiro , 3810-193 Aveiro, Portugal
| | - Andrei V Kovalevsky
- CICECO-Aveiro Institute of Materials, Department of Materials and Ceramic Engineering, University of Aveiro , 3810-193 Aveiro, Portugal
| | - Gonzalo Otero Irurueta
- Centre for Mechanical Technology and Automation (TEMA), Department of Mechanical Engineering, University of Aveiro , 3810-193 Aveiro, Portugal
| | - Sascha Populoh
- Empa, Materials for Energy Conversion , Ueberlandstrasse 129, CH-8600 Duebendorf, Switzerland.,Semiconductors, ABB Switzerland Ltd. , Fabrikstrasse 3, CH-5600 Lenzburg, Switzerland
| | - Philipp Thiel
- Empa, Materials for Energy Conversion , Ueberlandstrasse 129, CH-8600 Duebendorf, Switzerland
| | - Anke Weidenkaff
- Materials Chemistry, Institute for Materials Science, University of Stuttgart , Heisenbergstrasse 3, DE-70569 Stuttgart, Germany
| | - Fernando Neto da Silva
- Centre for Mechanical Technology and Automation (TEMA), Department of Mechanical Engineering, University of Aveiro , 3810-193 Aveiro, Portugal
| | - Duncan P Fagg
- Centre for Mechanical Technology and Automation (TEMA), Department of Mechanical Engineering, University of Aveiro , 3810-193 Aveiro, Portugal
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18
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Virtudazo RR, Guo Q, Wu R, Takei T, Mori T. An alternative, faster and simpler method for the formation of hierarchically porous ZnO particles and their thermoelectric performance. RSC Adv 2017. [DOI: 10.1039/c7ra05067d] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
A thermoelectric figure of merit (ZT) of 0.075 at ∼750 K (C) has been achieved, due to the synthesized micro/nanoporous ZnO powder.
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Affiliation(s)
- Raymond V. Rivera Virtudazo
- Thermal Energy Materials Group
- WPI Center for Materials Nanoarchitectonics (MANA)
- National Institute for Materials Science (NIMS)
- Tsukuba
- Japan
| | - Quansheng Guo
- Thermal Energy Materials Group
- WPI Center for Materials Nanoarchitectonics (MANA)
- National Institute for Materials Science (NIMS)
- Tsukuba
- Japan
| | - Rudder Wu
- Thermal Energy Materials Group
- WPI Center for Materials Nanoarchitectonics (MANA)
- National Institute for Materials Science (NIMS)
- Tsukuba
- Japan
| | - Toshiaki Takei
- RNFS/Nanofabrication Group
- WPI Center for Materials Nanoarchitectonics (MANA)
- National Institute for Materials Science (NIMS)
- Tsukuba
- Japan
| | - Takao Mori
- Thermal Energy Materials Group
- WPI Center for Materials Nanoarchitectonics (MANA)
- National Institute for Materials Science (NIMS)
- Tsukuba
- Japan
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