Estimation of corrosion conditions of a phosphoric acid fuel cell

Mitsuda, Kenro; Murahashi, Toshiaki; Matsumoto, Masafumi; Usami, Kouichi

doi:10.1007/bf00241570

Cited by 17 publications

(7 citation statements)

References 8 publications

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“…Carbon corrosion in PAFCs has been investigated extensively for years, using both actual PAFC electrodes − and model electrodes in phosphoric acid. − It is worth noting that, in PEMFCs, the material and structure of the gas diffusion electrode are similar to those used in PAFC cells. However, the choice of catalyst support in PAFCs has traditionally been graphitized versions of carbon.…”

Section: 52 Carbon Corrosion In Pafcsmentioning

confidence: 99%

“…It is therefore possible that the inner region of the carbon particles does not corrode in PEMFCs. Also in the case of PAFC, a mechanism of local cathode corrosion similar to the PEMFC reverse-current mechanism has been proposed. , Another major difference between carbon corrosion in PAFC and PEMFCs is that the water is present as liquid in PEMFC and acts as the oxidant during the corrosion reaction. It is worth noting, however, that carbon corrodes at potentials as low as 0.9 V in phosphoric acid at elevated temperature even for a cell that has uniform hydrogen coverage on the anode.…”

Section: 52 Carbon Corrosion In Pafcsmentioning

confidence: 99%

“…Carbon corrosion in PAFCs has been investigated extensively for years, using both actual PAFC electrodes [396][397][398][399][400][401][402] and model electrodes in phosphoric acid. [403][404][405][406][407][408][409][410][411][412] It is worth noting that, in PEMFCs, the material and structure of the gas diffusion electrode are similar to those used in PAFC cells.…”

Section: Carbon Corrosion In Pafcsmentioning

confidence: 99%

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Scientific Aspects of Polymer Electrolyte Fuel Cell Durability and Degradation

et al. 2007

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Section: 52 Carbon Corrosion In Pafcsmentioning

confidence: 99%

Section: 52 Carbon Corrosion In Pafcsmentioning

confidence: 99%

Section: Carbon Corrosion In Pafcsmentioning

confidence: 99%

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Scientific Aspects of Polymer Electrolyte Fuel Cell Durability and Degradation

et al. 2007

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“…Severe corrosion takes place at the cathode at high potential and high oxygen partial pressure. 24,25 Platinum dissolution/ agglomeration is enhanced by the presence of air and phosphoric acid and takes place at potentials above 0.8 V. 26,27 Platinum dissolution is assumed to be the main degradation process at 1.0 V. 27 The dissolution rate of platinum is a function of temperature and fuel cell potential. 28 For HT-PEFC it was reported that at cell voltages above 0.9 V cathode degradation is severe wheras the anode seems to be not affected.…”

Section: Catalyst Layer and Carbon Support Degradationmentioning

confidence: 99%

Accelerated Degradation of High-Temperature Polymer Electrolyte Fuel Cells: Discussion and Empirical Modeling

Reimer

Schumacher

Lehnert

2014

J. Electrochem. Soc.

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Accelerated stress tests are commonly applied in order to obtain a prediction of fuel cell life time within a short testing period. The stress test in this work considers a fuel cell which is constantly under load with frequent periods of very high current. Four different cells were operated each with a specific load profile. As a result severe performance degradation was observed in the region of high current densities. A short overview over the phenomena which may contribute to this specific fuel cell degradation is compiled from literature. Based on this overview major degradation modes are identified and combined with a simple polarization curve model. The modeling results allow for two different interpretations. Carbon corrosion reactions can explain the observed effects if cell voltage is assumed as the driving force for degradation. A better fit was obtained by using the overall heat flux as degradation criterion. In this case an increase in local temperature could lead to redistribution and loss of phosphoric acid from the MEA. The expected lifetime of a polymer electrolyte fuel cell (PEFC) ranges from 5 000 h for mobile application to 40 000 h for stationary application.1,2 In order to gain information about time dependent degradation in advance accelerated test protocols are used.3,4 Depending on the design of these tests valuable information about the nature of the main degradation mode under the applied operation conditions can be obtained. Despite the difference in operation conditions for PEFC, HT-PEFC and PAFC the structure and material of the electrodes are almost the same. Consequently, observed degradation phenomena show strong similarities.5 A good description of these phenomena can be found in several review papers 6-13 as well as in at least four books 1,2,14,15 where recent experimental facts and interpretations are summarized. A compact description can also be found in a recent review paper on modeling transport phenomena in PEFCs. 16 The purpose of this paper is to present the results of a specific accelerated degradation test for high temperature polymer electrolyte fuel cells (HT-PEFC) with phosphoric acid doped polybenzimidazole (PBI/H 3 PO 4 ) membranes. The fuel cell is constantly under load with frequent periods of very high current. In order to accelerate degradation effects the fuel cell is operated beyond it's point of maximum power. A simple polarization curve model is used as starting point for the analysis of data. Based on this first analysis a degradation model is proposed which allows for a straightforward physical interpretation. The complexity of degradation effects which occur simultaneousy usually leads to models which either resolve a specific mechanism in depth or describe more general effects. This paper aims at general effects which requires a broader understanding of degradation. In the following it is attempted to provide an overview over the phenomena which may contribute to fuel cell degradation. Based on this overview major degradation modes are identified and ...

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“…Mitsuda and Murahashi [47][48][49][50] have pioneered the use of multiple reference electrodes in phosphoric acid fuel cells (PAFC). In one of their studies [49], they have used 12 reference electrodes each on the anode and the cathode side to analyze both air and fuel starvations.…”

Section: Introductionmentioning

confidence: 99%

Dynamics of anode–cathode interaction in a polymer electrolyte fuel cell revealed by simultaneous current and potential distribution measurements under local reactant-starvation conditions

2015

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Low stoichiometry operation of fuel cells induces nonuniformities in the current generation and electrode potentials across the active electrode area. In this study, current and potential distributions are measured simultaneously in a fuel cell operating under reactant (fuel/ air)-starvation conditions. During the galvanostatic operation under local reactant starvation, the localized increase of current density is observed closer to the inlet. Here under air starvation, cathode potentials dropped uniformly across the electrode area. However, during fuel starvation, a nonuniform cathode potential profile is observed. During the potentiostatic mode of operation under air-starvation condition, cathode potentials remained uniform and constant across the electrode area. However, under fuel starvation, the cathode potential profile is influenced by the anode potential profile. Electrode-electrode interaction especially during fuel starvation is captured by simultaneous measurements of current and potential distribution.

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Estimation of corrosion conditions of a phosphoric acid fuel cell

Cited by 17 publications

References 8 publications

Scientific Aspects of Polymer Electrolyte Fuel Cell Durability and Degradation

Scientific Aspects of Polymer Electrolyte Fuel Cell Durability and Degradation

Accelerated Degradation of High-Temperature Polymer Electrolyte Fuel Cells: Discussion and Empirical Modeling

Dynamics of anode–cathode interaction in a polymer electrolyte fuel cell revealed by simultaneous current and potential distribution measurements under local reactant-starvation conditions

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