Modeling and Simulation of Steady-State Polarization and Impedance Response of Phosphoric Acid Fuel-Cell Cathodes with Catalyst-Layer Microstructure Consideration

Yang, S.C.

doi:10.1149/1.1393158

Cited by 6 publications

(3 citation statements)

References 17 publications

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“…It also describes the physicochemical phenomena that occur in those layers: gas diffusion in gas-filled pores, gas dissolution, dissolved gas diffusion in liquid-filled pores, ohmic conduction, and electrochemical reaction. We used a variation of the standard flooded agglomerate model [20][21][22][23][24][25][26][27][28][29][30] that has successfully described the diffusion, adsorption, and reaction phenomena in cathode and anode electrodes of hydrogen phosphoric acid fuel cells (PAFC) and polymer electrolyte fuel cells (PEMFC). The agglomerate model describes the electrode's catalyst layer as a collection of homogeneously distributed spherical agglomerates that are composed of carbon particles on which the electrocatalyst platinum particles are dispersed.…”

Section: Mathematical Model Descriptionmentioning

confidence: 99%

Mathematical model for a direct propane phosphoric acid fuel cell

et al. 2005

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A mathematical model was developed and used to predict the performance of direct propane phosphoric acid (PPAFC) fuel cells, utilizing both Pt/C state-of the-art electrodes and older Pt black electrodes. It was found that the overpotential caused by surface processes on the platinum catalyst in the anode is much greater than the potential losses caused by either ohmic resistance or propane diffusion in gas-filled and liquid-filled pores. In one comparison, the anode overpotential (0.5 V) was larger than the cathode overpotential (0.3 V) at a current density of 0.4 A cm )2 for Pt loadings 4 mg Pt cm )2 . The need for sufficient water concentration at the anode, where water is a reactant, was indicated by the large effect of H 3 PO 4 concentration. In another comparison, the model predicted that at 0.2 A cm )2 , modern carbon supported Pt catalysts would produce 0.35 V compared to 0.1 V for unsupported Pt black catalysts that were used several decades ago, when the majority of the research on direct hydrocarbon fuel cells was performed. The propane anode and oxygen cathode catalyst layers were modeled as agglomerates of spherical catalyst particles having their interior spaces filled with liquid electrolyte and being surrounded by gasfilled pores. The Tafel equation was used to describe the electrochemical reactions. The model incorporated gas and liquid-phase diffusion equations for the reactants in the anode and cathode and ionic transport in the electrolyte. Experimental data were used for propane and oxygen diffusivities, and for their solubilities in the electrolyte. The accuracy of the predicted electrical potentials and polarization curves were normally within ±0.02 V of values reported in experimental investigations of temperature and electrolyte concentration. Polarization curves were predicted as a function of temperature, pressure, electrolyte concentration, and Pt loading. A performance of 0.45 V at 0.5 A cm )2 was predicted at some conditions.

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Section: Mathematical Model Descriptionmentioning

confidence: 99%

Mathematical model for a direct propane phosphoric acid fuel cell

et al. 2005

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“…On the other hand, Pt loading in electrodes is still high in a system using liquid state electrolyte such as high temperature PEMFC and phosphoric acid fuel cells (PAFC) [20][21][22][23][24][25][26][27][28][29][30]. Because the liquid state PA cannot be fixed around catalyst, the maximum TPB and the optimum amount of electrolyte in electrodes are difficult to achieve.…”

Section: Introductionmentioning

confidence: 99%

“…Electrochemical impedance spectroscopy (EIS) has been actively used in fuel studies [6,7,16,18,27,30,[37][38][39][40][41]. An advantage of EIS is the capability to detect changes in impedance in situ with minimal perturbations of the fuel cell system.…”

Section: Introductionmentioning

confidence: 99%