Membrane polarization in mixed-conducting ceramic fuel cells and electrolyzers

Zhu, Huayang; Kee, Robert J.

doi:10.1016/j.ijhydene.2015.10.100

Cited by 71 publications

(58 citation statements)

References 35 publications

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“…It may well be that an even significantly lower value of N is not unreasonable. Therefore, these simple calculations do not indicate in favor of oxygen sites as a place for localization of holes, contrary to the common belief [25,26,41,42,43,44,45,46]. It seems more likely that the holes are localized on the cation impurities, especially taking into account that significantly different conductivity values were reported for BZY10 by different authors [7,47].…”

Section: Resultscontrasting

confidence: 60%

Thermoelectric Behavior of BaZr0.9Y0.1O3−d Proton Conducting Electrolyte

et al. 2019

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BaZr0.9Y0.1O3-δ (BZY10), a promising proton conducting material, exhibits p-type conduction under oxidative conditions. Holes in BZY10 are of the small polaron type. However, there is no clear understanding at which places in the lattice they are localized. The main objectives of this work were, therefore, to discuss the nature of electronic defects in BZY10 on the basis of the combined measurements of the thermo-EMF and conductivity. Total electrical conductivity and Seebeck coefficient of BZY10 were simultaneously studied depending on partial pressures of oxygen (pO2), water (pH2O) and temperature (T). The model equation for total conductivity and Seebeck coefficient derived on the basis of the proposed defect chemical approach was successfully fitted to the experimental data. Transference numbers of all the charge carriers in BZY10 were calculated. The heat of transport of oxide ions was found to be about one half the activation energy of their mobility, while that of protons was almost equal to the activation energy of their mobility. The results of the Seebeck coefficient modeling indicate that cation impurities, rather than oxygen sites, should be considered as a place of hole localization.

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Section: Resultscontrasting

confidence: 60%

Thermoelectric Behavior of BaZr0.9Y0.1O3−d Proton Conducting Electrolyte

et al. 2019

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“…One is based on palladium or palladium alloys [200] . The other is based on dense ceramic perovskites such as doped barium zirconates (e.g., BaZr 0.9 Y 0.1 O 3 −δ , BZY10), which are mixed ionic-electronic conductors [201][202][203][204] .…”

Section: Methane Dehydroaromatizationmentioning

confidence: 99%

“…The proton flux generally follows a NernstPlanck relationship, which depends on gradients of defect concentration and electrostatic potential [204] . Although these ceramic membranes are proton conductors, the ion conductivity is relatively low.…”

Section: Methane Dehydroaromatizationmentioning

confidence: 99%

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Process intensification in the catalytic conversion of natural gas to fuels and chemicals

Kee

Karakaya

Zhu

2017

Proceedings of the Combustion Institute

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This paper explores alternative technologies for the conversion of natural gas to higher-value products. Because of methane's chemical stability, all practical processes require elevated temperature (e.g., T > 700 °C) and catalysts to activate the methane. Some approaches are mature and widely practiced at the commercial scale (e.g., steam reforming and Fischer-Tropsch synthesis). Others are emerging, based on laboratory-scale experimentation (e.g., oxidative coupling of methane). In all cases, the present paper is concerned with aspects of process intensification, seeking chemical methods and reactor implementations that can improve overall performance. Performance metrics include reactor size, energy efficiency, conversion rates, and product selectivity. Process intensification approaches include integrated microchannel reactors and heat exchangers as well as a range of permselective membranes.

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“…The PNP system was successfully applied to the solid-state electrochemical systems, e.g., lithium batteries [7][8][9]. In [10], the PNP equations were already applied for proton ceramic fuel cells; however, the thermodynamics of the crystalline lattice and of the surface were not taken into account.…”

Section: Introductionmentioning

confidence: 99%

A continuum model for yttria-stabilized zirconia incorporating triple phase boundary, lattice structure and immobile oxide ions

Vágner

Guhlke

Miloš

et al. 2019

J Solid State Electrochem

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A continuum model for yttria-stabilized zirconia (YSZ) in the framework of non-equilibrium thermodynamics is developed. Particular attention is given to (i) modeling of the YSZ-metal-gas triple phase boundary, (ii) incorporation of the lattice structure and immobile oxide ions within the free energy model and (iii) surface reactions. A finite volume discretization method based on modified Scharfetter-Gummel fluxes is derived in order to perform numerical simulations. The model is used to study the impact of yttria and immobile oxide ions on the structure of the charged boundary layer and the double layer capacitance. Cyclic voltammograms of an air-half cell are simulated to study the effect of parameter variations on surface reactions, adsorption and anion diffusion.

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Membrane polarization in mixed-conducting ceramic fuel cells and electrolyzers

Cited by 71 publications

References 35 publications

Thermoelectric Behavior of BaZr0.9Y0.1O3−d Proton Conducting Electrolyte

Thermoelectric Behavior of BaZr0.9Y0.1O3−d Proton Conducting Electrolyte

Process intensification in the catalytic conversion of natural gas to fuels and chemicals

A continuum model for yttria-stabilized zirconia incorporating triple phase boundary, lattice structure and immobile oxide ions

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