Thermoelectric Oxide Ceramics and Devices: Comparison
Please note this is a comparison between Version 3 by Lindsay Dong and Version 2 by Lindsay Dong.

Thermoelectric materials have gained wide attention to realize multilevel efficient energy management to alleviate the increasingly severe energy crisis. Oxide ceramics were well-explored as potential thermoelectric candidates because of their outstanding merits, including abundance, eco-friendliness, high-temperature stability, and chemical stability. This entryA aims to provide a comprehensive summary of the diversified state-of-the-art oxide ceramics and establish the links between composition designing, preparation process, structural characteristics, and properties to summarize the underlying chemistry and physics mechanism of band engineering, doping, composited with the second phase, defects engineering, and entropy engineering is provided. Furthermore, advanced device design and applications such as thermoelectric modules, miniature generators, sensors, and coolers were summarized. Ultimately, the challenges and future perspective of oxides ceramics for the device design and thermoelectric applications in the development of energy harvesting technology have been prospected.

  • thermoelectrics
  • oxides ceramics
  • ZT
  • electrical conductivity
  • phonon scattering

1. Introduction

Thermoelectric materials (TEs) have been used as a potential energy harvesting technology because they can convert heat into electricity and have no requirements for waste heat temperature [1][2][3]. Thermoelectric devices generally consist of n-type and p-type TEs wired electrically in series (or partly parallel) and thermally in parallel. Furthermore, there are also thermoelectric devices with single n-type and p-type TEs. They have the advantages of no moving parts, no noise, small size, etc., and have significant application merits in the military, aerospace, and high-tech energy fields [4][5].

It has been more than 200 years since the thermoelectric effect was discovered, and people have been constantly exploring and developing its industrial applications. In the early 1920s, Altenkirch, a German physicist, developed the fundamentals of thermoelectric power generation and refrigeration and summarized the performance evaluation parameters of TEs [6]: electrical conductivity (σ), Seebeck coefficient (S), and thermal conductivity (κ). Dimensionless thermoelectric merit (ZT = S2σT/κ, S is Seebeck coefficient, σ is electrical conductivity, T is absolute temperature, κ is thermal conductivity) is usually used as an indicator to measure the thermoelectric performance [7]. TEs with large ZT values must meet the requirements of a high Seebeck coefficient to ensure the generation of the obvious thermoelectric effect—high electrical conductivity leading to small Joule heat, large output power, as well as low thermal conductivity, are required to generate a substantial temperature difference. The above three thermoelectric parameters have a strong coupled relationship because they are dependent on the carrier concentration in a conflicting manner that restricts and influences each other, making how to optimize thermoelectric performance a huge challenge. Therefore, the coordinated regulation of S, σ, and κ to improve ZT has become the key point to realize the industrial application of thermoelectric materials.

2. Thermoelectric Fundamentals

Thermoelectric materials utilize the thermoelectric effect to achieve direct heat-to-electricity conversion. As shown in the schematic diagrams in Figure 1, the thermoelectric effect includes three effects: (i) the Seebeck effect, which transforms heat into electricity; (ii) the Peltier effect, absorption or release of heat at a junction in which there is an electric current; and (iii) the Thomson effect [1], the evolution or absorption of heat when an electric current passes through a circuit composed of a single material that has a temperature difference along its length. The most common application of the Seebeck effect is the widely existing thermocouple, which can be used in thermometers, thermoelectric power generation, and other thermal cycle fields. Static cooling is the major application of the Peltier effect. The Thomson effect establishes a connection between the previous two and reflects their differential influence.

Figure 1. Schematic diagram of thermoelectric effects. (a) Seebeck effect for power generation, (b) Peltier effect for refrigeration, (c) Thomson effect for reversible cooling or heating.

3. Fabrication of Thermoelectric Oxide Ceramics

3.1. Lattice Structures of Thermoelectric Oxide Ceramics

3.1.1. n-Type Thermoelectric Oxides

As an n-type thermoelectric oxide, strontium titanate (SrTiO3) has attracted widespread interest due to its high effective mass of carriers, chemical and thermal stability at high temperatures, and high structural tolerance. SrTiO3 has a cubic perovskite structure and Pm3m space group at room temperature, and its lattice constant is a = b =c = 3.905 Å [8]. In a unit cell unit connected by solid lines in the figure, Ti4+ ions occupy the central position in the unit cell, Sr2+ ions occupy the eight vertex positions, O2- ions form an oxygen octahedron at the center of six faces of the cubic unit cell, and Ti4+ ions occupied the octahedral gaps. Therefore, the coordination number of Sr2+ ions is 12, and the coordination number of Ti4+ ions is 6. From another perspective, there is a cubic unit cell structure composed of eight Ti-O octahedrons in strontium titanate. Eight Ti-O octahedrons are located at the eight top corners of the cubic structure, while Sr2+ ions occupy the center of the cubic structure. The direct band gap of SrTiO3 is 3.2 eV, and its σ is very low. Its phase transitions from cubic to tetragonal will occur at temperatures below 105 K [9].

References

  1. Zebarjadi, M.; Esfarjani, K.; Dresselhaus, M.S.; Ren, Z.F.; Chen, G. Perspectives on thermoelectrics: From fundamentals to device applications. Energy Environ. Sci. 2012, 5, 5147–5162.
  2. He, J.; Tritt, T.M. Advances in thermoelectric materials research: Looking back and moving forward. Science 2017, 357, eaak9997.
  3. Zhu, K.; Deng, B.; Zhang, P.X.; Kim, H.S.; Jiang, P.; Liu, W.S. System efficiency and power: The bridge between the device and system of a thermoelectric power generator. Energy Environ. Sci. 2020, 13, 3514–3526.
  4. Bu, Z.L.; Zhang, X.Y.; Hu, Y.X.; Chen, Z.W.; Lin, S.Q.; Li, W.; Xiao, C.; Pei, Y.Z. A record thermoelectric efficiency in tellurium-free modules for low-grade waste heat recovery. Nat. Commun. 2022, 13, 237.
  5. Biswas, K.; He, J.Q.; Blum, I.D.; Wu, C.; Hogan, T.P.; Seidman, D.N.; Dravid, V.P.; Kanatzidis, M.G. High-performance bulk thermoelectrics with all-scale hierarchical architectures. Nature 2012, 489, 414–418.
  6. Altenkirch, E. Elektrothermische Kälteerzeugung und reversible elektrische Heizung. Phys. Z. 1911, 12, 920–924.
  7. Goupil, C.; Seifert, W.; Zabrocki, K.; Müller, E.; Snyder, G.J. Thermodynamics of thermoelectric phenomena and applications. Entropy 2011, 13, 1481–1517.
  8. Mitchell, R.H.; Chakhmouradian, A.R.; Woodward, P.M. Crystal chemistry of perovskite-type compounds in the tausonite-loparite series, (Sr1−2xNaxLax)TiO3. Phys. Chem. Miner. 2000, 27, 583–589.
  9. Nelmes, R.J.; Meyer, G.M.; Hutton, J. Thermal motion in SrTiO3 at room temperature: Anharmonic or disordered? Ferroelectrics 1978, 21, 461–462.
  10. Yang, W.C.; Zhang, H.C.; Tao, P.G.; Zhang, D.D.; Zhang, D.W.; Wang, Z.H.; Tang, G.D. Optimization of the spin entropy by incorporating magnetic ion in a misfit-layered calcium cobaltite. Ceram. Int. 2016, 42, 9744–9748.
  11. Wu, T.; Tyson, T.A.; Bai, J.M.; Pandya, K.; Jaye, C.; Fischer, D. On the origin of enhanced thermoelectricity in Fe doped Ca3Co4O9. J. Mater. Chem. C 2013, 1, 4114–4121.
  12. Zhao, L.D.; He, J.Q.; Berardan, D.; Lin, Y.H.; Li, J.F.; Nan, C.W.; Drago, N. BiCuSeO oxyselenides: New promising thermoelectric materials. Energy Environ. Sci. 2014, 7, 2900–2924.
  13. Liu, Y.; Zhao, L.D.; Zhu, Y.C.; Liu, Y.C.; Li, F.; Yu, M.J.; Liu, D.B.; Xu, W.; Lin, Y.H.; Nan, C.W. Synergistically optimizing electrical and thermal transport properties of BiCuSeO via a dual-doping approach. Adv. Energy Mater. 2016, 6, 1502423.
  14. Yang, D.W.; Su, X.L.; Yan, Y.G.; Hu, T.Z.; Xie, H.Y.; He, J.; Uher, C.; Kanatzidis, M.G.; Tang, X.F. Manipulating the combustion wave during self-propagating synthesis for high thermoelectric performance of layered oxychalcogenide Bi1−xPbxCuSeO. Chem. Mater. 2016, 28, 4628–4640.
  15. Schröer, P.; Krüger, P.; Pollmann, J. First-principles calculation of the electronic structure of the wurtzite semiconductors ZnO and ZnS. Phys. Rev. B 1993, 47, 6971–6980.
  16. Zhang, F.P.; Lu, Q.M.; Zhang, X.; Zhang, J.X. First principle investigation of electronic structure of CaMnO3 thermoelectric compound oxide. J. Alloys Compd. 2011, 509, 542–545.
  17. Ohta, H.; Sugiura, K.; Koumoto, K. Recent progress in oxide thermoelectric materials: P-type Ca3Co4O9 and n-type SrTiO3. Inorg. Chem. 2008, 47, 8429–8436.
  18. Assadi, M.H.N.; Katayama-Yoshida, H. Restoration of long range order of Na ions in NaxCoO2 at high temperatures by sodium site doping. Comput. Mater. Sci. 2015, 109, 308–311.
  19. Liu, Y.; Zhao, L.D.; Zhu, Y.C.; Liu, Y.C.; Li, F.; Yu, M.J.; Liu, D.B.; Xu, W.; Lin, Y.H.; Nan, C.W. Synergistically optimizing electrical and thermal transport properties of BiCuSeO via a dual-doping approach. Adv. Energy Mater. 2016, 6, 1502423.
  20. Fujita, K.; Mochida, T.; Nakamura, K. High-temperature thermoelectric properties of NaxCoO2-delta single crystals. Jpn. J. Appl. Phys. 2001, 40, 4644–4647.
  21. Zhu, B.B.; Chen, C.; Yao, Z.C.; Chen, J.Y.; Jia, C.; Wang, Z.H.; Tian, R.M.; Tao, L.; Xue, F.; Hng, H.H. Multiple doped ZnO with enhanced thermoelectric properties. J. Eur. Ceram. Soc. 2021, 41, 4182–4188.
  22. Kovalevsky, A.V.; Aguirre, M.H.; Populoh, S.; Patricio, S.G.; Ferreira, N.M.; Mikhalev, S.M.; Fagg, D.P.; Weidenkaff, A.; Frade, J.R. Designing strontium titanate-based thermoelectrics: Insight into defect chemistry mechanisms. J. Mater. Chem. A 2017, 5, 3909–3922.
  23. Hassanin, H.; Jiang, K. Net shape manufacturing of ceramic micro parts with tailored graded layers. J. Micromech. Microeng. 2014, 24, 015018.
  24. Hassanina, H.; Jiang, K. Fabrication and characterization of stabilised zirconia micro parts via slip casting and soft moulding. Scr. Mater. 2013, 69, 433–436.
  25. Wang, T.; Nan, P.F.; Wang, H.C.; Wang, H.; Su, W.; Sotelo, A.; Zhai, J.Z.; Wang, X.; Ran, Y.Z.; Chen, T.T.; et al. Right heterogeneous microstructure for achieving excellent thermoelectric performance in Ca0.9R0.1MnO3−δ(R.=Dy, Yb) Ceramics. Inorg. Chem. 2018, 57, 9133–9141.
  26. Zhang, P.; Lou, Z.H.; Qin, M.H.; Xu, J.; Zhu, J.T.; Shi, Z.M.; Chen, Q.; Reece, M.J.; Yan, H.X.; Gao, F. High-entropy (Ca0.2Sr0.2Ba0.2La0.2Pb0.2)TiO3 perovskite ceramics with A-site short-range disorder for thermoelectric applications. J. Mater. Sci. Technol. 2022, 97, 182–189.
  27. Kovalevsky, A.V.; Yaremchenko, A.A.; Populoh, S.; Populoh, S.; Frade, J.R. Enhancement of thermoelectric performance in strontium titanate by praseodymium substitution. J. Appl. Phys. 2013, 113, 053704.
  28. Lou, Z.H.; Zhang, P.; Gong, L.Y.; Xu, J.; Gong, L.Y.; Reece, M.J.; Yan, H.X.; Gao, F. A novel high-entropy perovskite ceramics Sr0.9La0.1(Zr0.25Sn0.25Ti0.25Hf0.25)O3 with low thermal conductivity and high Seebeck coefficient. J. Eur. Ceram. Soc. 2022, 42, 3480–3488.
  29. Han, J.; Song, Y.; Liu, X.; Wang, F.P. Sintering behavior and thermoelectric properties of LaCoO3 ceramics with Bi2O3-B2O3-SiO2 as a sintering aid. RSC Adv. 2014, 4, 51995–52000.
  30. Alvarez-Ruiz, D.T.; Azough, F.; Hernandez-Maldonado, D.; Kepaptsoglou, D.M.; Ramasse, Q.M.; Day, S.J.; Svec, P.; Svec, P.; Freer, R. Utilising unit-cell twinning operators to reduce lattice thermal conductivity in modular structures: Structure and thermoelectric properties of Ga2O3(ZnO)9. J. Alloys Compd. 2018, 762, 892–900.
  31. Nishiyama, S.; Ichikawa, A.; Hattori, T. Thermoelectric properties of CuO-added AgSbO3 ceramics. J. Ceram. Soc. Jpn. 2004, 112, 298–300.
  32. Azough, F.; Gholinia, A.; Alvarez-Ruiz, D.T.; Duran, E.; Kepaptsoglou, D.M.; Eggeman, A.S.; Ramasse, Q.M.; Freer, R. Self-nanostructuring in SrTiO3: A novel strategy for enhancement of thermoelectric response in oxides. ACS Appl. Mater. Interfaces 2019, 11, 32833–32843.
  33. Shi, Z.M.; Wang, L.X.; Li, L.L.; Wei, J.; Tong, S.J.; Zhang, J.Z.; Li, X.T.; Guo, Y.P.; Zhang, Y. Joint effect of Bi2O3 and CuO additives in regulating the thermoelectric properties of (Ca0.87Ag0.1Dy0.03)3Co4O9 composite ceramics. Mater. Sci. Eng. B 2023, 290, 116311.
  34. Wang, Y.F.; Zhang, X.Y.; Shen, L.M.; Bao, N.Z.; Wan, C.L.; Park, N.H.; Koumoto, K.; Gupta, A. Nb-doped grain boundary induced thermoelectric power factor enhancement in La-doped SrTiO3 nanoceramics. J. Power Sources 2013, 241, 255–258.
  35. Tian, T.; Cheng, L.H.; Xing, J.J.; Zheng, L.Y.; Man, Z.Y.; Hu, D.L.; Bernik, S.; Zeng, J.T.; Yang, J.; Liu, Y. Effects of sintering on the microstructure and electrical properties of ZnO-based thermoelectric materials. Mater. Des. 2017, 132, 479–485.
  36. Diaz-Chao, P.; Giovannelli, F.; Lebedev, O.; Chateigner, D.; Lutterotti, L.; Delorme, F.; Guilmeau, E. Textured Al-doped ZnO ceramics with isotropic grains. J. Eur. Ceram. Soc. 2014, 34, 4247–4256.
  37. Qin, M.J.; Lou, Z.J.; Shi, Z.J.; Zhang, R.J.; Xu, J.; Gao, F. Enhanced thermoelectric properties of Sr0.9La0.1TiO3 ceramics fabricated by SPS with nanosized Ti addition. J. Mater. Sci.-Mater. Electron. 2020, 31, 6919–6926.
  38. Chen, Y.X.; Shi, K.D.; Li, F.; Xu, X.; Ge, Z.H.; He, J.Q. Highly enhanced thermoelectric performance in BiCuSeO ceramics realized by Pb doping and introducing Cu deficiencies. J. Am. Ceram. Soc. 2019, 102, 5989–5996.
  39. Liu, D.Q.; Zhang, Y.W.; Kang, H.J.; Li, J.L.; Chen, Z.N.; Wang, T.M. Direct preparation of La-doped SrTiO3 thermoelectric materials by mechanical alloying with carbon burial sintering. J. Eur. Ceram. Soc. 2018, 38, 807–811.
  40. Park, K.; Son, J.S.; Woo, S.I.; Shin, K.; Oh, M.W.; Park, S.D.; Hyeon, T. Colloidal synthesis and thermoelectric properties of La-doped SrTiO3 nanoparticles. J. Mater. Chem. A 2014, 2, 4217–4224.
  41. Park, D.; Ju, H.; Kim, J. One-pot fabrication of Ag-SrTiO3 nanocomposite and its enhanced thermoelectric properties. Ceram. Int. 2019, 45, 16969–16975.
  42. Mehta, R.J.; Zhang, Y.L.; Karthik, C.; Singh, B.; Siegel, R.W.; Borca-Tasciuc, T.; Ramanath, G. A new class of doped nanobulk high-figure-of-merit thermoelectrics by scalable bottom-up assembly. Nat. Mater. 2012, 11, 233–240.
  43. Populoh, S.; Trottmann, M.; Aguire, M.H.; Weidenkaff, A. Nanostructured Nb-substituted CaMnO3 n-type thermoelectric material prepared in a continuous process by ultrasonic spray combustion. J. Mater. Res. 2011, 26, 1947–1952.
  44. Sun, Y.F.; Cheng, H.; Gao, S.; Liu, Q.H.; Sun, Z.H.; Xiao, C.; Wu, C.Z.; Wei, S.P.; Xie, Y. Atomically thick bismuth selenide freestanding single layers achieving enhanced thermoelectric energy harvesting. J. Am. Chem. Soc. 2012, 134, 20294–20297.
  45. Dehkordi, A.M.; Zebarjadi, M.; He, J.; Tritt, T.M. Thermoelectric power factor: Enhancement mechanisms and strategies for higher performance thermoelectric materials. Mater. Sci. Eng. R 2015, 97, 1–22.
  46. Wang, J.; Zhang, B.Y.; Kang, H.J.; Li, Y.; Yaer, X.B.; Li, J.F.; Tan, Q.; Zhang, S.; Fan, G.H.; Liu, C.Y.; et al. Record high thermoelectric performance in bulk SrTiO3 via nano-scale modulation doping. Nano Energy 2017, 35, 387–395.
  47. Qin, M.J.; Lou, Z.H.; Zhang, P.; Shi, Z.M.; Xu, J.; Chen, Y.S.; Gao, F. Enhancement of thermoelectric performance of Sr0.9La0.1TiO3-based ceramics regulated by nanostructures. ACS Appl. Mater. Interfaces 2020, 48, 53899–53909.
  48. Qin, M.J.; Gao, F.; Dong, G.G.; Xu, J.; Fu, M.S.; Wang, Y.; Reece, M.; Yan, H.X. Microstructure characterization and thermoelectric properties of Sr0.9La0.1TiO3 ceramics with nano-sized Ag as additive. J. Alloys Compd. 2018, 762, 80–89.
  49. Kovalevsky, A.V.; Yaremchenko, A.A.; Populoh, S.; Thiel, P.; Fagg, D.P.; Weidenkaff, A.; Frade, J.R. Towards a high thermoelectric performance in rare-earth substituted SrTiO3: Effects provided by strongly-reducing sintering conditions. Phys. Chem. Chem. Phys. 2014, 16, 26946–26954.
  50. Putri, Y.E.; Said, S.M.; Refinel, R.; Ohtaki, M.; Syukri, S. Low thermal conductivity of RE-doped SrO(SrTiO3)1 Ruddlesden Popper phase bulk materials prepared by molten salt method. Electron. Mater. Lett. 2018, 14, 556–562.
  51. Kahalya, M.U.; Schwingenschlögl, U. Thermoelectric performance enhancement of SrTiO3 by Pr doping. J. Mater. Chem. A 2014, 2, 10379–10383.
  52. Ito, M.; Ohira, N. Effects of TiB2 addition on spark plasma sintering and thermoelectric performance of Y-doped SrTiO3 synthesized by polymerized complex process. Compos. Part B Eng. 2016, 88, 108–113.
  53. Cui, Y.; Salvador, J.R.; Yang, J.; Wang, H.; Amow, G.; Kleinke, H. Thermoelectric properties of heavily doped n-type SrTiO3 bulk materials. J. Electron. Mater. 2009, 38, 1002–1007.
  54. Zhang, B.Y.; Wang, J.; Zou, T.; Zhang, S.; Yaer, X.B.; Ding, N.; Liu, C.Y.; Miao, L.; Li, Y.; Wu, Y. High thermoelectric performance of Nb-doped SrTiO3 bulk materials with different doping levels. J. Mater. Chem. C. 2015, 3, 11406–11411.
  55. Kovalevsky, A.V.; Populoh, S.; Patrício, S.G.; Thiel, P.; Ferro, M.C.; Fagg, D.P.; Frade, J.R.; Weidenkaff, A. Design of SrTiO3-based thermoelectrics by tungsten substitution. J. Phys. Chem. C 2015, 119, 4466–4478.
  56. Singsoog, K.; Seetawan, T.; Vora-Ud, A.; Thanachayanont, C. Theoretical enhancement of thermoelectric properties of Sr1−xLaxTiO3. Integr. Ferroelectr. 2014, 155, 111–118.
  57. Flahaut, D.; Mihara, T.; Funahashi, R.; Nabeshima, N.; Lee, K.; Ohta, H.; Koumoto, K. Thermoelectrical properties of A-site substituted Ca1−xRexMnO3 system. J. Appl. Phys. 2006, 100, 084911.
  58. Sanmathi, C.S.; Takahashi, Y.; Sawaki, D.; Klein, Y.; Retoux, R.; Terasaki, I.; Noudem, J.G. Microstructure control on thermoelectric properties of Ca0.96Sm0.04MnO3 synthesised by co-precipitation technique. Mater. Res. Bull. 2010, 45, 558.
  59. Kabir, R.; Tian, R.M.; Zhang, T.S.; Donelson, R.; Tan, T.T.; Li, S. Role of Bi doping in thermoelectric properties of CaMnO3. J. Alloys Compd. 2015, 628, 347–351.
  60. Kuganathan, N.; Chroneos, A. Defect and dopant properties in CaMnO3. AIP Adv. 2021, 11, 055106.
  61. Xu, G.J.; Funahashi, R.; Pu, Q.R.; Liu, B.; Tao, R.H.; Wang, G.S.; Ding, Z.J. High-temperature transport properties of Nb and Ta substituted CaMnO3 system. Solid State Ion. 2004, 171, 147–151.
  62. Bocher, L.; Aguirre, M.H.; Logvinovich, D.; Shkabko, A.; Robert, R.; Trottmann, M.; Weidenkaff, A. CaMn1−xNbxO3 (x ≤ 0.08) perovskite-type phases as promising new high-temperature n-type thermoelectric materials. Inorg. Chem. 2008, 47, 8077–8085.
  63. Zhu, Y.H.; Su, W.B.; Liu, J.; Zhou, Y.C.; Li, J.C.; Zhang, X.H.; Du, Y.L.; Wang, C.L. Effects of Dy and Yb co-doping on thermoelectric properties of CaMnO3 ceramics. Ceram. Int. 2015, 41, 1535–1539.
  64. Liu, K.K.; Liu, Z.Y.; Zhang, F.P.; Zhang, J.X.; Yang, X.Y.; Zhang, J.W.; Shi, J.L.; Ren, G.; He, T.W.; Duan, J.J. Improved thermoelectric performance in Pr and Sr Co-doped CaMnO3 materials. J. Alloys Compd. 2019, 808, 151476.
  65. Ohtaki, M.; Araki, K.; Yamamoto, K. High thermoelectric performance of dually doped ZnO ceramics. J. Electron. Mater. 2009, 38, 1234–1238.
  66. Pham, A.T.T.; Luu, T.A.; Pham, N.K.; Thi, H.K.; Nguyen, T.H.; Hoang, D.V.; Lai, H.T.; Tran, V.C.; Park, J.H.; Lee, J.K.; et al. Multi-scale defects in ZnO thermoelectric ceramic materials co-doped with In and Ga. Ceram. Int. 2020, 46, 10748–10758.
  67. Zhang, D.B.; Zhang, B.P.; Ye, D.S.; Liu, Y.C.; Li, S. Enhanced Al/Ni co-doping and power factor in textured ZnO thermoelectric ceramics prepared by hydrothermal synthesis and spark plasma sintering. J. Alloys Compd. 2016, 656, 784–792.
  68. Constantinescu, G.; Rasekh, S.; Torres, M.A.; Bosque, P.; Diez, J.C.; Madre, M.A.; Sotelo, A. Effect of Na doping on the Ca3Co4O9 thermoelectric performance. Ceram. Int. 2015, 41, 10897–10903.
  69. Zhang, L.; Liu, Y.; Tan, T.T.; Liu, Y.; Zheng, J.; Yang, Y.L.; Hou, X.J.; Feng, L.; Suo, G.Q.; Ye, X.H.; et al. Thermoelectric performance enhancement by manipulation of Sr/Ti doping in two sublayers of Ca3Co4O9. J. Adv. Ceram. 2020, 9, 769–781.
  70. Constantinescu, G.; Rasekh, S.; Torres, M.A.; Madre, M.A.; Sotelo, A.; Diez, J.C. Improvement of thermoelectric properties in Ca3Co4O9 ceramics by Ba doping. J. Mater. Sci. Mater. Electron. 2015, 26, 3466–3473.
  71. Shi, Z.M.; Su, T.C.; Zhang, P.; Lou, Z.H.; Qin, M.J.; Gao, T.; Xu, J.; Zhu, J.H.; Gao, F. Enhanced thermoelectric performance of Ca3Co4O9 ceramics through grain orientation and interface modulation. J. Mater. Chem. A 2020, 8, 19561–19572.
  72. Delorme, F.; Diaz-Chao, P.; Giovannelli, F. Effect of Ca substitution by Fe on the thermoelectric properties of Ca3Co4O9 ceramics. J. Electroceram. 2018, 40, 107–114.
  73. Demirel, S.; Altin, E.; Oz, E.; Altin, S.; Bayri, A. An enhancement ZT and spin state transition of Ca3Co4O9 with Pb doping. J. Alloys Compd. 2015, 627, 430–437.
  74. Park, K.; Hakeem, D.A.; Cha, J.S. Synthesis and structural properties of thermoelectric Ca3−xAgxCo4O9+δ powders. Dalton Trans. 2016, 45, 6990–6997.
  75. Constantinescu, G.; Madre, M.A.; Rasekh, S.; Torres, M.A.; Diez, J.C.; Sotelo, A. Effect of Ga addition on Ca-deficient Ca3Co4O9 thermoelectric materials. Ceram. Int. 2014, 40, 6255–6260.
  76. Saini, S.; Yaddanapudi, H.S.; Tian, K.; Yin, Y.; Magginetti, D.; Tiwari, A. Terbium ion doping in Ca3Co4O9: A step towards high-performance thermoelectric materials. Sci. Rep. 2017, 7, 44621.
  77. Bhaskar, A.; Huang, Y.C.; Liu, C. Improvement on the low-temperature thermoelectric characteristics of Ca3−xYbxCo4O9+δ (0 ≤ x ≤ 0.10). Ceram. Int. 2014, 40, 5937–5943.
  78. Yang, W.C.; Qian, H.J.; Gan, J.Y.; Wei, W.; Wang, Z.H.; Tang, G.D. Effects of Lu and Ni substitution on thermoelectric properties of Ca3Co4O9+δ. J. Electron. Mater. 2016, 45, 4171–4176.
  79. Wang, Y.; Sui, Y.; Ren, P.; Wang, L.; Wang, X.J.; Su, W.H.; Fan, H.J. Strongly correlated properties and enhanced thermoelectric response in Ca3Co4−xMxO9 (M = Fe, Mn, and Cu). Chem. Mater. 2009, 22, 1155–1163.
  80. Huang, Y.A.; Zhao, B.C.; Lin, S.; Ang, R.; Song, W.H.; Sun, Y.P. Strengthening of thermoelectric performance via Ir doping in layered Ca3Co4O9 system. J. Am. Ceram. Soc. 2014, 97, 798–804.
  81. Zhang, P.; Lou, Z.H.; Gong, L.Y.; Xu, J.; Chen, Q.; Reece, M.J.; Yan, H.X.; Dashevsky, Z.; Gao, F. High-entropy MTiO3 perovskite oxides with glass-like thermal conductivity for thermoelectric applications. J. Alloys Compd. 2023, 937, 168366.
  82. Zhang, P.; Gong, L.Y.; Lou, Z.H.; Xu, J.; Cao, S.Y.; Zhu, J.T.; Yan, H.X.; Gao, F. Reduced lattice thermal conductivity of perovskite-type high-entropy (Ca0.25Sr0.25Ba0.25RE0.25)TiO3 ceramics by phonon engineering for thermoelectric applications. J. Alloys Compd. 2022, 898, 162858.
  83. Zhang, P.; Lou, Z.H.; Hu, G.X.; Wu, Z.Z.; Xu, J.; Gong, L.Y.; Gao, F. In-situ construction of all-scale hierarchical microstructure and thermoelectric properties of (Sr0.25Ca0.25Ba0.25La0.25)TiO3/Pb@Bi composite oxide ceramics. J. Mater. 2023; in press.
  84. Zhang, R.Z.; Gucci, F.; Zhu, H.Y.; Chen, K.; Reece, M.J. Data-driven design of ecofriendly thermoelectric high-entropy sulfides. Inorg. Chem. 2018, 57, 13027–13033.
  85. Liu, R.H.; Chen, H.Y.; Zhao, K.P.; Qin, Y.T.; Jiang, B.B.; Zhang, T.S.; Sha, G.; Shi, X.; Uher, C.; Zhang, W.Q.; et al. Entropy as a gene-like performance indicator promoting thermoelectric materials. Adv. Mater. 2017, 29, 1702712.
  86. Zhang, P.; Lou, Z.H.; Qin, M.H.; Xu, J.; Zhu, J.T.; Shi, Z.M.; Chen, Q.; Reece, M.J.; Yan, H.X.; Gao, F. High-entropy (Ca0.2Sr0.2Ba0.2La0.2Pb0.2)TiO3 perovskite ceramics with A-site short-range disorder for thermoelectric applications. J. Mater. Sci. Technol. 2022, 97, 182–189.
  87. Zhang, P.; Lou, Z.H.; Gong, L.Y.; Xu, J.; Chen, Q.; Reece, M.J.; Yan, H.X.; Dashevsky, Z.; Gao, F. High-entropy MTiO3 perovskite oxides with glass-like thermal conductivity for thermoelectric applications. J. Alloys Compd. 2023, 937, 168366.
  88. Zhang, P.; Gong, L.Y.; Lou, Z.H.; Xu, J.; Cao, S.Y.; Zhu, J.T.; Yan, H.X.; Gao, F. Reduced lattice thermal conductivity of perovskite-type high-entropy (Ca0.25Sr0.25Ba0.25RE0.25)TiO3 ceramics by phonon engineering for thermoelectric applications. J. Alloys Compd. 2022, 898, 162858.
  89. Langenberg, E.; Ferreiro-Vila, E.; Leborán, V.; Fumega, A.O.; Pardo, V.; Rivadulla, F. Analysis of the temperature dependence of the thermal conductivity of insulating single crystal oxides. APL Mater. 2016, 4, 104815.
  90. Yu, J.C.; Chen, K.; Azough, F.; Alvarez-Ruiz, D.T.; Reece, M.J.; Freer, R. Enhancing the thermoelectric performance of Calcium Cobaltite ceramics by tuning composition and processing. ACS Appl. Mater. Interfaces 2020, 12, 47634–47646.
  91. Li, Z.; Xiao, C.; Fan, S.J.; Deng, Y.; Zhang, W.S.; Ye, B.J.; Xie, Y. Dual vacancies: An effective strategy realizing synergistic optimization of thermoelectric property in BiCuSeO. J. Am. Chem. Soc. 2015, 137, 6587–6593.
  92. Sanmathi, C.S.; Takahashi, Y.; Sawaki, D.; Klein, Y.; Retoux, R.; Terasaki, I.; Noudem, J.G. Microstructure control on thermoelectric properties of Ca0.96Sm0.04MnO3 synthesised by co-precipitation technique. Mater. Res. Bull. 2010, 45, 558.
  93. Lou, Z.H.; Zhang, P.; Gong, L.Y.; Xu, J.; Gong, L.Y.; Reece, M.J.; Yan, H.X.; Gao, F. A novel high-entropy perovskite ceramics Sr0.9La0.1(Zr0.25Sn0.25Ti0.25Hf0.25)O3 with low thermal conductivity and high Seebeck coefficient. J. Eur. Ceram. Soc. 2022, 42, 3480–3488.
  94. Zhang, P.; Lou, Z.H.; Gong, L.Y.; Xu, J.; Chen, Q.; Reece, M.J.; Yan, H.X.; Dashevsky, Z.; Gao, F. High-entropy MTiO3 perovskite oxides with glass-like thermal conductivity for thermoelectric applications. J. Alloys Compd. 2023, 937, 168366.
  95. Devi, N.Y.; Vijayakumar, K.; Rajasekaran, P.; Nedunchezhian, A.S.A.; Sidharth, D.; Masaru, S.; Arivanandhan, M.; Jayavel, R. Effect of Gd and Nb co-substitution on enhancing the thermoelectric power factor of nanostructured SrTiO3. Ceram. Int. 2021, 47, 3201–3208.
  96. Buscaglia, M.T.; Maglia, F.; Anselmi-Tamburini, U.; Marré, D.; Pallecchi, I.; Ianculescu, A.; Canu, G.; Viviani, M.; Fabrizio, M.; Buscaglia, V. Effect of nanostructure on the thermal conductivity of La-doped SrTiO3 ceramics. J. Eur. Ceram. Soc. 2014, 34, 307–316.
  97. Wang, Y.F.; Fujinami, K.; Zhang, R.Z.; Wan, C.L.; Wang, N.; Ba, Y.S.; Koumoto, K. Interfacial thermal resistance and thermal conductivity in nanograined SrTiO3. Appl. Phys. Express 2010, 3, 031101.
  98. Ohta, S.; Nomura, T.; Ohta, H.; Koumoto, K. High-temperature carrier transport and thermoelectric properties of heavily La- or Nb-doped SrTiO3 single crystals. J. Appl. Phys. 2005, 97, 034106.
  99. Dehkordi, A.M.; Bhattacharya, S.; Darroudi, T.; Graff, J.W.; Schwingenschlogl, U.; Alshareef, H.N.; Tritt, T.M. Large thermoelectric power factor in Pr-Doped SrTiO3-δ ceramics via grain-boundary-induced mobility enhancement. Chem. Mater. 2014, 26, 2478–2485.
  100. Dehkordi, A.M.; Bhattacharya, S.; He, J.; Alshareef, H.N.; Tritt, T.M. Significant enhancement in thermoelectric properties of polycrystalline Pr-doped SrTiO3−δ ceramics originating from nonuniform distribution of Pr dopants. Appl. Phys. Lett. 2014, 104, 193902.
  101. Srivastava, D.; Norman, C.; Azough, F.; Schäfer, M.C.; Guilmeau, E.; Freer, R. Improving the thermoelectric properties of SrTiO3-based ceramics with metallic inclusions. J. Alloys Compd. 2018, 731, 723–730.
  102. Zhang, P.; Qin, M.J.; Lou, Z.H.; Cao, S.Y.; Gong, L.Y.; Xu, J.; Reece, M.J.; Yan, H.X.; Dashevsky, Z.; Gao, F. Grain orientation evolution and multi-scale interfaces enhanced thermoelectric properties of textured Sr0.9La0.1TiO3 based ceramics. J. Eur. Ceram. Soc. 2022, 42, 7017–7026.
  103. Shi, Z.M.; Su, T.C.; Zhang, P.; Lou, Z.H.; Qin, M.J.; Gao, T.; Xu, J.; Zhu, J.H.; Gao, F. Enhanced thermoelectric performance of Ca3Co4O9 ceramics through grain orientation and interface modulation. J. Mater. Chem. A 2020, 8, 19561–19572.
  104. Zhang, P.; Qin, M.J.; Lou, Z.H.; Cao, S.Y.; Gong, L.Y.; Xu, J.; Reece, M.J.; Yan, H.X.; Dashevsky, Z.; Gao, F. Grain orientation evolution and multi-scale interfaces enhanced thermoelectric properties of textured Sr0.9La0.1TiO3 based ceramics. J. Eur. Ceram. Soc. 2022, 42, 7017–7026.
  105. Jana, S.S.; Maiti, T. Enhanced thermoelectric performance in oxide composites of La and Nb codoped SrTiO3 by using graphite as the electron mobility booster. ACS Appl. Mater. Interfaces 2022, 14, 14174–14181.
  106. Bolotin, K.I.; Sikes, K.J.; Jiang, Z.; Klima, M.; Fudenberg, G.; Hone, J.; Kim, P.; Stormer, H.L. Ultrahigh electron mobility in suspended graphene. Solid State Commun. 2008, 146, 351–355.
  107. Ekren, D.; Cao, J.Y.; Azough, F.; Kepaptsoglou, D.; Ramasse, Q.; Kinloch, I.A.; Freer, R. Controlling the thermoelectric behavior of La-doped SrTiO3 through processing and addition of graphene oxide. ACS Appl. Mater. Interfaces 2022, 14, 53711–53723.
  108. Dey, P.; Jana, S.S.; Anjum, F.; Bhattacharya, T.; Maiti, T. Effect of semiconductor to metal transition on thermoelectric performance in oxide nanocomposites of SrTi0.85Nb0.15O3 with graphene oxide. Appl. Mater. Today 2020, 21, 100869.
  109. Yin, Y.N.; Tudu, B.; Tiwari, A. Recent advances in oxide thermoelectric materials and modules. Vacuum 2017, 146, 356–374.
  110. Lim, C.H.; Choi, S.M.; Seo, W.S.; Lee, M.H.; Lee, K.H.; Park, H.H. A study of electrodes for thermoelectric oxides. Electron. Mater. Lett. 2013, 9, 445–449.
  111. Tougas, I.M.; Amani, M.; Gregory, O.J. Metallic and ceramic thin film thermocouples for gas turbine engines. Sensors 2013, 13, 15324–15347.
  112. Yakaboylu, G.A.; Pillai, R.C.; Sabolsky, K.; Sabolsky, E.M. Fabrication and thermoelectric characterization of transition metal silicide-based composite thermocouples. Sensors 2018, 18, 3759.
  113. Repaka, D.V.M.; Suwardi, A.; Kumar, P. New paradigm for efficient thermoelectrics. In Energy Saving Coating Materials; Elsevier: Amsterdam, The Netherlands, 2020; pp. 183–196.
  114. Kraemer, D.; Poudel, B.; Feng, H.P.; Caylor, J.C.; Yu, B.; Yan, X.; Ma, Y.; Wang, X.W.; Wang, D.Z.; Muto, A.; et al. High-performance flat-panel solar thermoelectric generators with high thermal concentration. Nat. Mater. 2011, 10, 532–538.
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