Optimization of the Cathode Composition for the Intermediate-Temperature SOFC

Lust, Enn; Möller, Priit; Kivi, Indrek; Nurk, Gunnar; Kallip, Silvar; Nigu, Priit; Lust, Karmen

doi:10.1149/1.2103727

Cited by 28 publications

(89 citation statements)

References 23 publications

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“…In addition, the equivalent circuit with Gerischer element, 29 given in Fig. 13f (EC 2), has been applied for fitting the calculated spectra to the experimental Nyquist plots and in a good agreement with our previous results, [10][11][12][17][18][19] a more pronounced deviation of calculated spectra from experimental data has been established in the low-frequency ac region (Fig. 13f).…”

Section: Modeling Of Experimental Datasupporting

confidence: 81%

“…pores and micropores, respectively. [10][11][12][17][18][19] Data in Fig. 6 show that the highest total polarization resistance (R p ) values have been measured for single cell completed with cathode, sintered at highest sintering temperature (T Sint = 1423 K), however, demonstrating the smallest figure).…”

Section: Electrochemical Results and Discussionmentioning

confidence: 97%

“…The semicircles represent the electrode electrical response, and therefore the semicircle at very high frequency area f > 20 kHz describes mainly the impedance response at the electrolyte grain boundaries. [4][5][6]10,11,[13][14][15][16][17][18][19] The comparatively high very high frequency resistance values are caused by the co-sintering of anode, yttria-stabilized zirconia and gadolinia-doped ceria at moderate sintering temperature T = 1623 K for 3h. Usually, higher sintering temperatures (1823 K) have been used for good sintering homogenisation to achieve good ionic conductivity of gadolinia-doped ceria electrolytes.…”

Section: Electrochemical Results and Discussionmentioning

confidence: 99%

“…Usually, higher sintering temperatures (1823 K) have been used for good sintering homogenisation to achieve good ionic conductivity of gadolinia-doped ceria electrolytes. [10][11][12][17][18][19] In addition, taking into account the meso/macro porous nature of the cathode ( Fig. 1) (and also anode) the contact resistance between electrolyte and cathode is somewhat higher than that for microporous cathode, contacting better with well sintered Ce 0.9 Gd 0.1 O 2−δ electrolyte.…”

Section: Electrochemical Results and Discussionmentioning

confidence: 99%

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Influence of Microstructural Parameters of LSC Cathodes on the Oxygen Reduction Reaction Parameters

Kivi

Anderson

Möller

et al. 2012

J. Electrochem. Soc.

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The solid oxide fuel cell single cells with porous cathodes prepared at various sintering temperatures, having remarkable differences in micro/meso porosity, were studied using impedance, cyclic voltammetry and chronoamperometry measurement methods. Atomic force microscopy, scanning electron microscopy, focused ion beam-scanning electron microscopy, Brunauer-Emmett-Teller and X-ray diffraction methods were used to describe the cathode material physical and porosity characteristics. It was demonstrated that the porosity and surface area of a cathode strongly depend on the cathode sintering temperature. Influence of single cell working temperature, electrode polarization and oxidant and or fuel partial pressure onto the single cell electrochemical behavior, has been analyzed. Power density vs. current density plots show that the electrical power of single cells depend noticeably on the cathode porosity, O 2 partial pressure in the cathode as well as on H 2 partial pressure in the anode compartment. Impedance data were analyzed in detail, using equivalent circuit fitting as well as difference derivative impedance vs. log frequency plots method. It was concluded that the characteristic time constants for the cathode and anode processes are very similar and the exact separation of the anode and cathode processes characteristics is complicated.Increasing interest in the operation of the solid oxide fuel cells (SOFC) at temperatures considerably lower than 1273 K has raised the need for a better understanding of the factors limiting the performance of the complex solid oxide based catalyst electrodes. [1][2][3][4][5][6][7][8][9][10][11][12] Strontium activated lanthanum cobaltite La 1−x Sr x CoO 3−δ (LSC) is a perovskite-type oxide with high electronic and oxide ion conductivity at moderate temperatures (773-973 K) and is therefore considered as catalyst for medium-temperature devices such as fuel cells, ceramic membrane electrolysers and synthetic fuel reactors. The mixed electronic-ionic conductivity of LSC is believed to account for the low overpotentials of the processes at SOFC cathode as mixed conductivity expands the catalytically active area of the electrode beyond the triple phase boundary. 7 The rate of oxygen reduction process on and inside of the cathode is limiting for SOFC single cell. [2][3][4][5][6]8,9 It was established that the polarization resistance of the cathode process depends on the processing route of the cathode and electrolyte powder. [10][11][12] In addition, the structure, thickness and porosity of active layers depend on the coating technology (screen printing, slurry spraying) and also on the procedure and characteristics applied during sintering (temperature and duration of sintering, co-firing, infiltration of active particles) of cathodes and anodes. [3][4][5][6]9 Besides, it was demonstrated that the interaction between electrolyte and perovskite type cathode is sensitive to the processing procedures used for preparation of anode and electrolyte and it is crucial for electrocatalytic p...

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Section: Modeling Of Experimental Datasupporting

confidence: 81%

Section: Electrochemical Results and Discussionmentioning

confidence: 97%

Section: Electrochemical Results and Discussionmentioning

confidence: 99%

Section: Electrochemical Results and Discussionmentioning

confidence: 99%

See 2 more Smart Citations

Influence of Microstructural Parameters of LSC Cathodes on the Oxygen Reduction Reaction Parameters

Kivi

Anderson

Möller

et al. 2012

J. Electrochem. Soc.

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“…The fitting curves match the experimental data very well with a fitting 2 error about 10 −4 . In this simplified equivalent circuit, L lead is the lead inductance, R e is the electrolyte ohmic resistance, R ap is the polarization resistance of the anode, R cp is the polarization resistance of cathode, C a represents the polarization capacitance of anode, C c represents the polarization capacitance of cathode and W s is the finite length Warburg short circuit terminus that simulates oxygen oxidant mass transport and diffusion process in the cathode [41][42][43]. L lead , R e , R ap , R cp , C a , C c , and W s are fitting parameters, their values are obtained from above curve fittings.…”

Section: Ac Impedances and Analysesmentioning

confidence: 99%

High performance metal-supported intermediate temperature solid oxide fuel cells fabricated by atmospheric plasma spraying

Hwang

Tsai

et al. 2011

Journal of Power Sources

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Comparative study of the crystallographic expansion of GSC and LSC porous electrodes

et al. 2021

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Characteristics of the porous Gd 0.15 Sr 0.85 CoO 3−δ and La 0.6 Sr 0.4 CoO 3−δ cathodes were compared using the data measured at different electrode potentials and oxygen partial pressures. The electrochemical high-temperature in situ XRD (HT-XRD) method combined with electrochemical impedance spectroscopy has been used. The response of the crystallographic parameters and impedance values on the changes of electrode potential has been discussed. Reversible changes of the lattice parameters for both cathodes, slower for Gd 0.15 Sr 0.85 CoO 3−δ compared with La 0.6 Sr 0.4 CoO 3−δ , were observed depending on temperature (T), electrode potential (E), and oxygen partial pressure (pO 2 ). The crystallographic parameters are determined by the vacancy formation kinetics as well as by vacancy formation energy in/at the cathode grain structure. Calculated impedance data were fitted to the experimental data and characteristics were obtained in context of crystallographic changes of the cathode materials studied. K E Y W O R D Scathode characteristics, in situ XRD, solid oxide fuel cell INTRODUCTIONPerovskite-type ABO 3 complex oxides are of interest as catalysts for oxygen reduction reaction in solid oxide fuel cell (SOFC) cathodes, and as an anode in oxygen separation membranes. In solid oxide electrolysis mode, the above mentioned reaction is known as oxygen evolution reaction (OER) [1][2][3][4][5][6][7][8]. The properties of these materials, developed and discussed as most important ones for afore mentioned Abbreviation: EC, equivalent circuits; G, Gerisher impedance element; GDC, gadolinia-doped ceria (Ce 0.9 Gd 0.1 O 2-δ ); GSC, Gd 0.15 Sr 0.85 CoO 3−δ ; HT-XRD, high temperature X-ray diffraction; LSC, La 0.6 Sr 0.4 CoO 3−δ ; SOFC, solid oxide fuel cell; XANES, X-ray absorption near edge spectroscopy; W S , Generalized Finite Warburg elementThis is an open access article under the terms of the Creative Commons Attribution-NonCommercial-NoDerivs License, which permits use and distribution in any medium, provided the original work is properly cited, the use is non-commercial and no modifications or adaptations are made.

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Optimization of the Cathode Composition for the Intermediate-Temperature SOFC

Cited by 28 publications

References 23 publications

Influence of Microstructural Parameters of LSC Cathodes on the Oxygen Reduction Reaction Parameters

Influence of Microstructural Parameters of LSC Cathodes on the Oxygen Reduction Reaction Parameters

High performance metal-supported intermediate temperature solid oxide fuel cells fabricated by atmospheric plasma spraying

Comparative study of the crystallographic expansion of GSC and LSC porous electrodes

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