Solid oxide fuel cell cathodes prepared by infiltration of LaNi0.6Fe0.4O3 and La0.91Sr0.09Ni0.6Fe0.4O3 in porous yttria-stabilized zirconia

Lee, Shiwoo; Bevilacqua, Manuela; Fornasiero, Paolo; Vohs, John M.; Gorte, Raymond J.

doi:10.1016/j.jpowsour.2009.04.046

Cited by 61 publications

(35 citation statements)

References 46 publications

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“…15 Of particular importance here is the fact that all of the parameters from our calculations, with the exception of S 0 , have been measured in the characterization of these electrodes.…”

Section: Model Implications and Example Calculationsmentioning

confidence: 99%

“…4,13 However, in studies using composites prepared by infiltrating various perovskites into porous scaffolds of yttria-stabilized zirconia (YSZ), there was no measurable difference in the cathode impedances observed for perovskites with ionic conductivities that differed by as much as 600 times, even though preparation by infiltration methods allowed all of the composites to have similar structures. 14,15 In another example, it is frequently assumed that cathode performance is limited by catalytic properties. However, even though the addition of various promoters has been reported to improve the performance of common cathode materials in some studies, 16,17 our laboratory has determined that the enhancement appears to be due to structural changes in the electrode, rather than to any enhanced catalytic or ionic-conduction properties, since inert additives enhanced performance as much as catalytic ones.…”

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confidence: 99%

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Modeling Impedance Response of SOFC Cathodes Prepared by Infiltration

Bidrawn

Vohs

Gorte

2011

J. Electrochem. Soc.

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A mathematical model has been developed to understand the performance of electrodes prepared by infiltration of La 0.8 Sr 0.2 FeO 3 (LSF) and La 0.8 Sr 0.2 MnO 3 (LSM) into yttria-stabilized zirconia (YSZ). The model calculates the resistances for the case where perovskite-coated, YSZ fins extend from the electrolyte. Two rate-limiting cases are considered: oxygen ion diffusion through the perovskite film or reactive adsorption of O 2 at the perovskite surface. Adsorption is treated as a reaction between gas-phase O 2 and oxygen vacancies, using equilibrium data. With the exception of the sticking probability, all parameters in the model are experimentally determined. Resistances and capacitances are calculated for LSF-YSZ and there is good agreement with experimental values at 973 K, assuming adsorption is rate limiting, with a sticking probability between 10 À3 and 10 À4 on vacancy sites. According to the model, perovskite ionic conductivity does not limit performance so long as it is above $10 À7 S/cm. However, the structure of the YSZ scaffold, the ionic conductivity of the scaffold, and the slope of the perovskite redox isotherm significantly impact electrode impedance. Finally, it is shown that characteristic frequencies of the electrode cannot be used to distinguish when diffusion or adsorption is rate-limiting.

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“…15 Of particular importance here is the fact that all of the parameters from our calculations, with the exception of S 0 , have been measured in the characterization of these electrodes.…”

Section: Model Implications and Example Calculationsmentioning

confidence: 99%

mentioning

confidence: 99%

Modeling Impedance Response of SOFC Cathodes Prepared by Infiltration

Bidrawn

Vohs

Gorte

2011

J. Electrochem. Soc.

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“…However, the SiO2 support had low electrical conductivity, thus it was required to be mixed with a conductive component such as silver to increase the electrical conductivity [10]. In addition, the performance-limiting factor in solid oxide fuel cells (SOFC) is often the electrode impedance [11][12][13] which can be avoided by using low-temperature, infiltration procedures to synthesize the electrodes [14][15][16][17]. This procedure involves a preparation of porous YSZ (dense YSZ is the electrolyte) scaffold together with the electrolyte layer, then infiltrating the required precursor salts to form the particle within the scaffold.…”

Section: Introductionmentioning

confidence: 99%

Synthesis of Na2WO4-Mn Supported YSZ as a Potential Anode Catalyst for Oxidative Coupling of Methane in SOFC Reactor

Appamana

Charojrochkul

Assabumrungrat

et al. 2015

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Abstract. The oxidative coupling of methane (OCM) over a 5%Na2WO4-2%Mn on YSZ, has been investigated in a fixed bed reactor (FBR) and a solid oxide fuel cell reactor (SOFC). A 60% C2 selectivity and a 26% CH4 conversion have been obtained in a FBR at 800 o C and CH4/O2 of 4:1. Importantly, an addition of Na2WO4-Mn to YSZ support can significantly enhance the performance of the catalyst especially C2 hydrocarbons selectivity and CH4 conversion. A maximum power density of 7.8 mW cm −2 was achieved at 800°C with CH4 in the SOFC reactor having a 50 μm thick YSZ electrolyte. The CH4 conversion and C2 selectivity at 800°C were 1.1% and 85.2%, respectively.

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“…1373 K) dramatically decrease the surface area of the LSF phase and lead to a significant increase in the non-ohmic electrode resistance at open circuit. 4,[7][8][9]27,28,[31][32][33][34] It is important to point out that due to the relatively simple microstructure, the electrochemical characteristics of infiltrated SOFC cathodes can be described in terms of mathematical models with no or very few fitting parameters. 7,8,25,26 The electrode kinetics do not exhibit Tafelian behavior and the oxygen reduction reactions should not be described in terms of Butler-Volmer kinetics.…”

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confidence: 99%

An Investigation of Oxygen Reduction Kinetics in LSF Electrodes

Küngas

Levine

et al. 2012

J. Electrochem. Soc.

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The characteristics of solid oxide fuel cell (SOFC) cathodes, prepared by infiltration of La0.8Sr0.2FeO3−δ (LSF) into porous yttria-stabilized zirconia (YSZ) scaffolds, were evaluated by studying the effect of p(O2) and of Al2O3 overlayers deposited by Atomic Layer Deposition (ALD) on impedance spectra at 873 and 973 K. The electrode resistance of LSF-YSZ composites calcined at 1123 K was dominated by high-frequency processes that show a relatively weak p(O2) dependence of −0.2 at 973 K. Composites calcined to 1373 K exhibited additional, low-frequency features in their impedance spectra that were more strongly dependent on p(O2), −0.43. These low-frequency processes are due to O2 adsorption limitations caused by the lower surface area of the LSF phase. Decreases in the exposed LSF surface caused by ALD films caused similar changes in the impedance spectra. The ALD overlayers were disrupted by heating to 1073 K and electrode polarization at 873 K. The implications of these results for understanding O2 adsorption limitations on SOFC cathodes are discussed.

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Solid oxide fuel cell cathodes prepared by infiltration of LaNi0.6Fe0.4O3 and La0.91Sr0.09Ni0.6Fe0.4O3 in porous yttria-stabilized zirconia

Cited by 61 publications

References 46 publications

Modeling Impedance Response of SOFC Cathodes Prepared by Infiltration

Modeling Impedance Response of SOFC Cathodes Prepared by Infiltration

Synthesis of Na2WO4-Mn Supported YSZ as a Potential Anode Catalyst for Oxidative Coupling of Methane in SOFC Reactor

An Investigation of Oxygen Reduction Kinetics in LSF Electrodes

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