Estudio de perovskitas LaBaCo_2O_6-delta: propiedades de alta temperatura y su evaluación como potenciales materiales para celdas de combustible o electrolíticas de óxido sólido. / A research on perovskites LaBaCo_2O_6-delta: high temperature properties and potential applications as fuel cells or solid-oxide electrolitic cells.

Garcés, Diana A. (2012) Estudio de perovskitas LaBaCo_2O_6-delta: propiedades de alta temperatura y su evaluación como potenciales materiales para celdas de combustible o electrolíticas de óxido sólido. / A research on perovskites LaBaCo_2O_6-delta: high temperature properties and potential applications as fuel cells or solid-oxide electrolitic cells. Master in Physical Sciences, Universidad Nacional de Cuyo, Instituto Balseiro.

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Abstract in Spanish

En esta tesis se estudia la influencia del método de síntesis para la obtención de las estructuras perovskitas con ordenamiento catiónico, LaBaCo_2O_6-δ, y sin él, La_0.5Ba_0.5CoO_3-δ. Se realiza un estudio de las propiedades de alta temperatura de estos compuestos y se los evalúan como potenciales materiales para celdas de combustible o electrolíticas de óxidos sólido. En la primera parte de esta tesis se obtienen las fases ordenada (LaBaCo_2O_6-δ) y desordenada (La_0.5Ba_0.5CoO_3-δ) mediante el método de síntesis de Reacción de Estado Sólido. Utilizando de manera combinada técnicas de difracción de rayos X (DRX), difracción de neutrones (DNP) y termogravimetría se realiza un estudio detallado de sus propiedades estructurales. Para el análisis de los datos de DRX y DNP se utiliza el método de Rietveld, donde se prueban diferentes modelos de refinamiento, obteniendo información estructural como por ejemplo parámetros de red, tensiones, vibraciones atómicas, distancias y ángulos entre enlaces, etc. Estos resultados se combinan con los obtenidos del análisis de las propiedades de transporte eléctrico consiguiendo así información sobre el mecanismo de conducción eléctrica, tipo de portadores, ordenamiento de vacancias de oxígeno, etc. En la segunda parte, se busca obtener las fases ordenada y desordenada pero a través de otro método de síntesis, aplicando técnicas de sol-gel partiendo de acetatos y realizando una policondensación con Acetil Acetona y Hexametiltetramina. Este método, llamado HMTA, permitiría conseguir dichas fases en condiciones más suaves de temperatura y/o tiempo y con menor tamaño de cristalita, lo cual mejoraría sus propiedades como cátodo. En esta búsqueda se preparan muestras obtenidas bajo diferentes condiciones de síntesis (variando temperatura, tiempo de síntesis y atmósfera) a las que se les realiza un estudio detallado de la estructura utilizando de manera combinada las técnicas de DRX y HR-TEM. Se intenta comprender la manera en que se produce el ordenamiento catiónico de las muestras a partir de fases intermedias. En la tercera parte de esta tesis se investigan los mecanismos limitantes de la reacción de reducción de oxígeno en los compuestos con y sin ordenamiento catiónico obtenidos mediante el método RES y en el compuesto sintetizado mediante el método de síntesis HMTA a 900 °C en argón (900Ar). Para realizar este estudio se utiliza la técnica de espectroscopía de impedancia electroquímica (EIS) en celdas simétricas electrodo/electrolito/electrodo. Se examinan diferentes condiciones de temperatura y presión parcial de oxígeno con el objetivo de determinar los mecanismos que controlan la reacción de electrodo. Para finalizar se detallan las conclusiones del trabajo realizado, analizando la aplicabilidad de las muestras como materiales para celdas de combustible o electrolíticas de óxidos sólido.

Abstract in English

In this thesis, the influence of synthesis method to obtain perovskites with cationic order, LaBaCo_2O_6-δ, and without it, La_0.5Ba_0.5CoO_3-δ, is studied. The high temperature properties of these compounds are analyzed and they are evaluated as potential materials for fuel or electrolytic solid oxide cells. First, ordered (LaBaCo_2O_6-δ) and disordered (La_0.5Ba_0.5CoO_3-δ) phases are obtained by Solid State Reaction (SSR). Their structural properties are studied in detail by combining XRD, NPD and TGA techniques. For diffraction data analysis the Rietveld’s method is used by essaying different refinement models and obtaining structural information such as lattice parameters, stresses, atomic vibrations, bond distances and angles, etc. This information is combined with results from electric transport experiments for determining the electric conduction mechanism, type of charge carriers, ordering of vacancies, etc. In the second part, the obtaining of ordered and disordered phases is looked by means of another synthesis method, applying sol-gel techniques staring from acetates and performing a poly-condensation with AcAc and hexametiltetramine. This method, called HMTA, would allow preparing these phases at lower temperatures and/or shorter times, with smaller crystallite sizes, which would improve their properties for cathode materials. In this search, different batches of samples are obtained under different annealing conditions (temperature, time and atmosphere); their structures are analyzed in detail by combining XRD and HR-TEM. The possible path followed for ordering or disordering, from intermediate phases, is discussed. In the third part of this thesis, the rate limiting steps of oxygen reduction reaction are evaluated on ordered and disordered compounds obtained by SSR and the one prepared by HMTA and annealed at 900ºC in Ar. This analysis is made by Electrochemical Impedance Spectroscopy (EIS) on symmetric electrode/electrolyte/electrode cells. The EIS experiments are carried out at different temperatures and oxygen partial pressures with the aim of determining the mechanisms that control the electrode reaction. At the end, the conclusions of the complete study are summarized, analyzing the applicability of these materials as electrodes for fuel or electrolytic solid oxide cells.

Item Type:Thesis (Master in Physical Sciences)
Keywords:Perovskite; Perovskita; Fuel Cells; Celulas de combustible; Solid oxide fuel cells; Celulas de combustible oxido solido; X-ray diffraction; Difracción de rayos X; Neutron diffraction; Difracción de neutrones; Acetylacetone; Acetilacetona; Hexametiltetramine; Hexametiltetramina
References:[1] F. Nishiwaki, T. Inagaki, J. Kano, J. Akikusa, N. Murakami, K. Hosoi, Development of disc-type intermediate-temperature solid oxide fuel cell, Journal of Power Sources. 157 (2006) 809–815. [2] E. Fontell, T. Kivisaari, N. Christiansen, J.-B. Hansen, J. Pålsson, Conceptual study of a 250kW planar SOFC system for CHP application, Journal of Power Sources. 131 (2004) 49–56. [3] James Larminie, Fuel Cell Systems Explained, John Wiley & Sons Ltd, The Atrium, Southern Gate, Chichester, West Sussex PO19 8SQ, England. (2003). [4] R. Steinberger-Wilckens, European SOFC Technology - Status and Trends, in: ECS Transactions, The Electrochemical Society, 2011: pp. 19–29. [5] Shailesh D. Vora, Recent Developments in the SECA Program Plenary Papers, ECS Transactions. (2011) 35: 3. [6] U.C. Castillo, “http://www.iie.org.mx/reno99/apli.pdf” Generación de electricidad limpia y eficiente vía electroquímica, Boletín Iie. (1999). [7] M.N. Manage, D. Hodgson, N. Milligan, S.J.R. Simons, D.J.L. Brett, A techno-economic appraisal of hydrogen generation and the case for solid oxide electrolyser cells, International Journal of Hydrogen Energy. 36 (2011) 5782–5796. [8] W. Zając, E. Hanc, A. Gorzkowska-Sobas, K. Świerczek, J. Molenda, Nd-doped Ba(Ce,Zr)O3−δ proton conductors for application in conversion of CO2 into liquid fuels, Solid State Ionics. 225 (2012) 297–303. [9] E. Gorbova, V. Maragou, D. Medvedev, a. Demin, P. Tsiakaras, Investigation of the protonic conduction in Sm doped BaCeO3, Journal of Power Sources. 181 (2008) 207–213. [10] C. Deportes, M. Duclot, P. Fabry, L. Fouletier, A. Hammou, M. Kleitz, et al., Electrochimie des Solides, Presses Universitaires de Grenoble, Grenoble, 1994. [11] F. Abraham, J. Boivin, G. Mairesse, G. Nowogrocki, The bimevox series: A new family of high performances oxide ion conductors, Solid State Ionics. 40-41 (1990) 934–937. [12] Steele, K.M. Hori, S. Uchino, Kinetic parameters influencing the performance of IT-SOFC composite electrodes, 135 (2000) 445–450. [13] J. Larminie, A. Dicks, Fuel Cell Systems Explained, 2da ed., John Wiley and Sons, England, 2003. [14] E. Siebert, A. Hammouche, M. Kleitz, Impedance spectroscopy analysis of La1−xSrxMnO3−d yttria-stabilized zirconia electrode kinetics, 40 (1995). [15] Y. Teraoka, H.M. Zhang, K. Okamoto, N. Yamazoe, Mixed ionic-electronic conductivity of La1−xSrxCo1−yFeyO3−δ perovskite-type oxides, Materials Research Bulletin. 23 (1988) 51–58. [16] Z. Shao, S.M. Haile, A high-performance cathode for the next generation of solid-oxide fuel cells., Nature. 431 (2004) 170–3. [17] J.-H. Kim, L. Mogni, F. Prado, a. Caneiro, J. a. Alonso, a. Manthiram, High Temperature Crystal Chemistry and Oxygen Permeation Properties of the Mixed Ionic–Electronic Conductors LnBaCo[sub 2]O[sub 5+δ] (Ln=Lanthanide), Journal of The Electrochemical Society. 156 (2009) B1376. [18] R.D. Shannon, Revised effective ionic radii and systematic studies of interatomic distances in halides and chalcogenides, Acta Crystallographica Section A. 32 (1976) 751–767. [19] E. Rautama, P. Boullay, A.K. Kundu, V. Caignaert, V. Pralong, M. Karppinen, et al., Cationic Ordering and Microstructural Effects in the Ferromagnetic Properties, (2008) 2742–2750. [20] L. Baqué, A. Caneiro, M.S. Moreno, A. Serquis, High performance nanostructured IT-SOFC cathodes prepared by novel chemical method, Electrochemistry Communications. 10 (2008) 1905–1908. [21] B.D. Cullity, Element of X-RAY diffraction, second edi, Eddison-Wesley publishing company, inc., 1978. [22] G.E. Bacon, Neutron Diffraction, 1st ed. -, Oxford at the Clarendon Press Hardcover, 1955. [23] Francis, Taylor, Special Feature section of neutron scattering lengths and cross sections of the elements and their isotopes, Neutron News. 3 (1992) 29–37. [24] J. Rodríguez-Carvajal, FullProf 2000: A Program for Rietveld Refinement and Profile Matching Analisis of Complex Powder Diffraction Patterns, Laboratoire Léon Brillouin (CEA-CNRS), Francia, 2001. [25] J. Goldstein, D.E. Newbury, D.C. Joy, C.E. Lyman, P. Echlin, E. Lifshin, et al., Scanning Electron Microscopy and X-ray Microanalysis, Springer, 2003 [26] D.B.W.C.B. Carter, D. B. Williams’s C. Barry Carter's Transmission Electron Microscopy 2nd(Second) edition (Transmission Electron Microscopy: A Textbook for Materials Science [Hardcover])(2009), Springer, 2009. [27] P.A. Stadelmann, JEMS - a software package for electron diffraction analysis and HREM image simulation in materials science, Ultramicroscopy. 21 (1987) 131–145. [28] P. Bavdaz, J. Fouletier, J.P. Abriata, A. Caneiro, Adaptation of an electrochemical system for measurement and regulation of oxygen partial pressure to a symmetrical thermogravimetric analysis system developed using a Cahn 1000 electrobalance, Review of Scientific Instruments. 53 (1982) 1072. [29] S. Associates, ZViewTM, A Software Program for IES Measurements and Analysis, (2007). [30] R. Doshi, Development of Solid-Oxide Fuel Cells That Operate at 500°C, Journal of The Electrochemical Society. 146 (1999) 1273. [31] C.F. Setevich, L. V. Mogni, A. Caneiro, F.D. Prado, Optimum cathode configuration for IT-SOFC using La0.4Ba0.6CoO3−δ and Ce0.9Gd0.1O1.95, International Journal of Hydrogen Energy. 37 (2012) 14895–14901. [32] P.W. Stephens, Phenomenological model of anisotropic peak broadening in powder diffraction, Journal of Applied Crystallography. 32 (1999) 281–289. [33] S. Streule, a. Podlesnyak, E. Pomjakushina, K. Conder, D. Sheptyakov, M. Medarde, et al., Oxygen order–disorder phase transition in PrBaCo2O5.48 at high temperature, Physica B: Condensed Matter. 378-380 (2006) 539–540. [34] L. Tai, M.M. Nasrallah, H.U. Anderson, D.M. Sparlin, S.R. Sehlin, Structure and electrical properties of La1-xSrxCo1-yO3. Part 2. The system La1-xSrxCo0.2Fe0.8O3, Solid State Ionics. 2738 (1995). [35] A.Y. Suntsov, I. a. Leonidov, M.V. Patrakeev, V.L. Kozhevnikov, High-temperature electron–hole transport in PrBaCo2O5+δ, Journal of Solid State Chemistry. 184 (2011) 1951–1955. [36] K. Zhang, L. Ge, R. Ran, Z. Shao, S. Liu, Synthesis, characterization and evaluation of cation-ordered LnBaCo2O5+δ as materials of oxygen permeation membranes and cathodes of SOFCs, Acta Materialia. 56 (2008) 4876–4889. [37] S.L. Pang, X.N. Jiang, X.N. Li, Q. Wang, Q.Y. Zhang, Structural stability and high-temperature electrical properties of cation-ordered/disordered perovskite LaBaCoO, Materials Chemistry and Physics. 131 (2012) 642–646. [38] S.R. Sehlin, H.U. Anderson, D.M. Sparlin, Semiempirical model for the electrical properties of La1-xCaxCoO3, Physical Review B. 52 (1995). [39] E. Ivers-Tiffée, A. Weber, D. Herbstritt, Materials and technologies for SOFC-components, Journal of the European Ceramic Society. 21 (2001) 1805–1811. [40] S.B. Adler, Factors governing oxygen reduction in solid oxide fuel cell cathodes., Chemical Reviews. 104 (2004) 4791–843.
Subjects:Physics > Physics of materials
Divisions:Aplicaciones de la energía nuclear > Tecnología de materiales y dispositivos > Caracterización de materiales
ID Code:390
Deposited By:Marisa G. Velazco Aldao
Deposited On:14 Feb 2013 11:13
Last Modified:14 Feb 2013 11:13

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