Journal Home > Volume 9 , issue 6

Thermoelectric (TE) performance of Ca3Co4O9 (CCO) has been investigated extensively via a doping strategy in the past decades. However, the doping sites of different sublayers in CCO and their contributions to the TE performance remain unrevealed because of its strong correlated electronic system. In this work, Sr and Ti are chosen to realize doping at the [Ca2CoO3] and [CoO2] sublayers in CCO. It was found that figure of merit (ZT) at 957 K of Ti-doped CCO was improved 30% than that of undoped CCO whereas 1 at% Sr doping brought about a 150% increase in ZT as compared to undoped CCO. The significant increase in electronic conductivity and the Seebeck coefficient are attributed to the enhanced carrier concentration and spin-entropy of Co4+ originating from the Sr doping effects in [Ca2CoO3] sublayer, which are evidenced by the scanning electron microscope (SEM), Raman, Hall, and X-ray photoelectron spectroscopy (XPS) analysis. Furthermore, the reduced thermal conductivity is attributed to the improved phonon scattering from heavier Sr doped Ca site in [Ca2CoO3] sublayer. Our findings demonstrate that doping at Ca sites of [Ca2CoO3] layer is a feasible pathway to boost TE performance of CCO material through promoting the electronic conductivity and the Seebeck coefficient, and reducing the thermal conductivity simultaneously. This work provides a deep understanding of the current limited ZT enhancement on CCO material and provides an approach to enhance the TE performance of other layered structure materials.


menu
Abstract
Full text
Outline
About this article

Thermoelectric performance enhancement by manipulation of Sr/Ti doping in two sublayers of Ca3Co4O9

Show Author's information Li ZHANGa( )Yichen LIUbThiam Teck TANbYi LIUaJian ZHENGbYanling YANGaXiaojiang HOUaLei FENGaGuoquan SUOaXiaohui YEaSean LIb
Shaanxi Key Laboratory of Green Preparation and Functionalization for Inorganic Materials, School of Materials Science and Engineering, Shaanxi University of Science & Technology, Xi’an 710021, China
UNSW Materials and Manufacturing Futures Institute, School of Material Science and Engineering, The University of New South Wales, Kensington, New South Wales, 2052, Australia

† Li Zhang and Yichen Liu contributed equally to this work.

Abstract

Thermoelectric (TE) performance of Ca3Co4O9 (CCO) has been investigated extensively via a doping strategy in the past decades. However, the doping sites of different sublayers in CCO and their contributions to the TE performance remain unrevealed because of its strong correlated electronic system. In this work, Sr and Ti are chosen to realize doping at the [Ca2CoO3] and [CoO2] sublayers in CCO. It was found that figure of merit (ZT) at 957 K of Ti-doped CCO was improved 30% than that of undoped CCO whereas 1 at% Sr doping brought about a 150% increase in ZT as compared to undoped CCO. The significant increase in electronic conductivity and the Seebeck coefficient are attributed to the enhanced carrier concentration and spin-entropy of Co4+ originating from the Sr doping effects in [Ca2CoO3] sublayer, which are evidenced by the scanning electron microscope (SEM), Raman, Hall, and X-ray photoelectron spectroscopy (XPS) analysis. Furthermore, the reduced thermal conductivity is attributed to the improved phonon scattering from heavier Sr doped Ca site in [Ca2CoO3] sublayer. Our findings demonstrate that doping at Ca sites of [Ca2CoO3] layer is a feasible pathway to boost TE performance of CCO material through promoting the electronic conductivity and the Seebeck coefficient, and reducing the thermal conductivity simultaneously. This work provides a deep understanding of the current limited ZT enhancement on CCO material and provides an approach to enhance the TE performance of other layered structure materials.

Keywords:

layered structures, manipulation doping sites, Ca3Co4O9 (CCO), spin-entropy, thermoelectric performance
Received: 29 May 2020 Revised: 18 August 2020 Accepted: 21 August 2020 Published: 27 November 2020 Issue date: December 2020
References(42)
[1]
GJ Snyder, ES Toberer. Complex thermoelectric materials. Nature Mater 2008, 7: 105-114.
[2]
LP Hu, HJ Wu, TJ Zhu, et al. Tuning multiscale microstructures to enhance thermoelectric performance of n-type bismuth-telluride-based solid solutions. Adv Energy Mater 2015, 5: 1500411.
[3]
XK Hu, P Jood, M Ohta, et al. Power generation from nanostructured PbTe-based thermoelectrics: Comprehensive development from materials to modules. Energy Environ Sci 2016, 9: 517-529.
[4]
S Chen, ZF Ren. Recent progress of half-Heusler for moderate temperature thermoelectric applications. Mater Today 2013, 16: 387-395.
[5]
M Bittner, N Kanas, R Hinterding, et al. A comprehensive study on improved power materials for high-temperature thermoelectric generators. J Power Sources 2019, 410-411: 143-151.
[6]
YC Liu, WX Wang, J Yang, et al. Recent advances of layered thermoelectric materials. Adv Sustainable Syst 2018, 2: 1800046.
[7]
M Shikano, R Funahashi. Electrical and thermal properties of single-crystalline (Ca2CoO3)0.7CoO2 with a Ca3Co4O9 structure. Appl Phys Lett 2003, 82: 1851-1853.
[8]
TY Liu, DY Bao, Y Wang, et al. Exploring thermoelectric performance of Ca3Co4O9+δ ceramics via chemical electroless plating with Cu. J Alloys Compd 2020, 821: 153522.
[9]
MA Torres, G Garcia, I Urrutibeascoa, et al. Fast preparation route to high-performances textured Sr-doped Ca3Co4O9 thermoelectric materials through precursor powder modification. Sci China Mater 2019, 62: 399-406.
[10]
H Liu, GC Lin, XD Ding, et al. Mechanical relaxation in thermoelectric oxide Ca3−xSrxCo4O9+δ (x = 0, 0.25, 0.5, 1.0) associated with oxygen vacancies. J Solid State Chem 2013, 200: 305-309.
[11]
G Constantinescu, S Rasekh, MA Torres, et al. Effect of Sr substitution for Ca on the Ca3Co4O9 thermoelectric properties. J Alloys Compd 2013, 577: 511-515.
[12]
MA Torres, FM Costa, D Flahaut, et al. Significant enhancement of the thermoelectric performance in Ca3Co4O9 thermoelectric materials through combined strontium substitution and hot-pressing process. J Eur Ceram Soc 2019, 39: 1186-1192.
[13]
RF Klie, Q Qiao, T Paulauskas, et al. Observations of Co4+ in a higher spin state and the increase in the Seebeck coefficient of thermoelectric Ca3Co4O9. Phys Rev Lett 2012, 108: 196601.
[14]
S Butt, W Xu, WQ He, et al. Enhancement of thermoelectric performance in Cd-doped Ca3Co4O9 via spin entropy, defect chemistry and phonon scattering. J Mater Chem A, 2014, 2: 19479-19487.
[15]
YC Liu, L Zhang, SE Shirsath, et al. Manipulation of charge carrier concentration and phonon scattering via spin-entropy and size effects: Investigation of thermoelectric transport properties in La-doped Ca3Co4O9. J Alloys Compd 2019, 801: 60-69.
[16]
C Boyle, P Carvillo, Y Chen, et al. Grain boundary segregation and thermoelectric performance enhancement of bismuth doped calcium cobaltite. J Eur Ceram Soc 2016, 36: 601-607.
[17]
RM Tian, R Donelson, CD Ling, et al. Ga substitution and oxygen diffusion kinetics in Ca3Co4O9+δ-based thermoelectric oxides. J Phys Chem C 2013, 117: 13382-13387.
[18]
JC Diez, MA Torres, S Rasekh, et al. Enhancement of Ca3Co4O9 thermoelectric properties by Cr for Co substitution. Ceram Int 2013, 39: 6051-6056.
[19]
SF Wang, YF Hsu, JH Chang, et al. Characteristics of Cu and Mo-doped Ca3Co4O9−δ cathode materials for use in solid oxide fuel cells. Ceram Int 2016, 42: 11239-11247.
[20]
T Wu, TA Tyson, JM Bai, et al. On the origin of enhanced thermoelectricity in Fe doped Ca3Co4O9. J Mater Chem C 2013, 1: 4114-4121.
[21]
RM Tian, TS Zhang, DW Chu, et al. Enhancement of high temperature thermoelectric performance in Bi, Fe co-doped layered oxide-based material Ca3Co4O9+δ. J Alloys Compd 2014, 615: 311-315.
[22]
FK Lotgering. Topotactical reactions with ferrimagnetic oxides having hexagonal crystal structures—II. J Inorg Nucl Chem 1960, 16: 100-108.
[23]
ME Song, H Lee, min-gyu Kang, et al. Anisotropic thermoelectric performance and sustainable thermal stability in textured Ca3Co4O9/Ag nanocomposites. ACS Appl Energy Mater 2019, 2: 4292-4301.
[24]
WJ Li, J Wang, B Poudel, et al. Filiform metal silver nanoinclusions to enhance thermoelectric performance of P-type Ca3Co4O9+δ oxide. ACS Appl Mater Interfaces 2019, 11: 42131-42138.
[25]
ME Song, H Lee, MG Kang, et al. Nanoscale texturing and interfaces in compositionally modified Ca3Co4O9 with enhanced thermoelectric performance. ACS Omega 2018, 3: 10798-10810.
[26]
M An, SK Yuan, Y Wu, et al. Raman spectra of a misfit layered Ca3Co4O9 single crystal. Phys Rev B 2007, 76: 024305.
[27]
PH Tsai, MHN Assadi, TS Zhang, et al. Immobilization of Na ions for substantial power factor enhancement: Site-specific defect engineering in Na0.8CoO2. J Phys Chem C 2012, 116: 4324-4329.
[28]
P Lemmens, KY Choi, V Gnezdilov, et al. Anomalous electronic Raman scattering in NaxCoO2·yH2O. Phys Rev Lett 2006, 96: 167204.
[29]
SK Yuan, M An, Y Wu, et al. Raman-scattering study of misfit-layered (Bi,Pb)-Sr-Co-O single crystal. J Appl Phys 2007, 101: 113527.
[30]
YN Huang, BC Zhao, S Lin, et al. Enhanced thermoelectric performance induced by misplaced substitution in layered Ca3Co4O9. J Phys Chem C 2015, 119: 7979-7986.
[31]
M Schrade, S Casolo, PJ Graham, et al. Oxygen Nonstoichiometry in (Ca2CoO3)0.62(CoO2): A combined experimental and computational Study. J Phys Chem C 2014, 118: 18899-18907.
[32]
ZM Shi, F Gao, JH Zhu, et al. Influence of liquid-phase sintering on microstructure and thermoelectric properties of Ca3Co4O9-based ceramics with Bi2O3 additive. J Materiomics 2019, 5: 711-720.
[33]
ZM Shi, J Xu, LH Zhu, et al. High thermoelectric performance of Ca3Co4O9 ceramics with duplex structure fabricated via two-step pressureless sintering. J Mater Sci: Mater Electron 2020, 31: 2938-2948.
[34]
GD Tang, ZH Wang, XN Xu, et al. Evidence of spin-density-wave transition and enhanced thermoelectric properties in Ca3-xCexCo4O9+δ. J Appl Phys 2010, 107: 053715.
[35]
GD Tang, F Xu, DW Zhang, et al. Improving the spin entropy by suppressing Co4+ concentration in thermoelectric Ca3Co4O9+δ. Ceram Int 2013, 39: 1341-1344.
[36]
I Terasaki, Y Sasago, K Uchinokura. Large thermoelectric power in NaCo2O4 single crystals. Phys Rev B 1997, 56: r12685.
[37]
Zou J, Park J, Yoon H, et al. Preparation and evaluation of Ca3−xBixCo4O9−δ (0 < x ≤ 0.5) as novel cathodes for intermediate temperature-solid oxide fuel cells. Int J Hydrogen Energ 2012, 37: 8592-8602.10.1016/j.ijhydene.2012.02.132
[38]
HS Kim, ZM Gibbs, YL Tang, et al. Characterization of Lorenz number with Seebeck coefficient measurement. APL Mater 2015, 3: 041506.
[39]
DR Clarke. Materials selection guidelines for low thermal conductivity thermal barrier coatings. Surf Coat Technol 2003, 163: 67-74.
[40]
KL Peng, X Lu, H Zhan, et al. Broad temperature plateau for high ZTs in heavily doped p-type SnSe single crystals. Energy Environ Sci 2016, 9: 454-460.
[41]
XL Shi, K Zheng, M Hong, et al. Boosting the thermoelectric performance of p-type heavily Cu-doped polycrystalline SnSe via inducing intensive crystal imperfections and defect phonon scattering. Chem Sci 2018, 9: 7376-7389.
[42]
K Watari, H Nakano, K Urabe, et al. Thermal conductivity of AlN ceramic with a very low amount of grain boundary phase at 4 to 1000 K. J Mater Res 2002, 17: 2940-2944.
Publication history
Copyright
Acknowledgements
Rights and permissions

Publication history

Received: 29 May 2020
Revised: 18 August 2020
Accepted: 21 August 2020
Published: 27 November 2020
Issue date: December 2020

Copyright

© The Author(s) 2020

Acknowledgements

This study was financially supported by the National Natural Science Foundation of China (Grant No. 51802181), the Natural Science Foundation of Shaanxi Province (Grant No. 2019JQ-771), and the Foundation of Shaanxi University of Science &Technology (Grant No. 2017GBJ-03).

Rights and permissions

This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made.

The images or other third party material in this article are included in the article’s Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder.

To view a copy of this licence, visit http://creativecommons. org/licenses/by/4.0/.

Reprints and Permission requests may be sought directly from editorial office.

Return