Effect of operational potential on performance decay rate in a phosphoric acid fuel cell

Aragane, J.; Urushibata, Hiroaki; Murahashi, Toshiaki

doi:10.1007/bf00364064

Cited by 57 publications

(52 citation statements)

References 9 publications

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“…Similarly, Yasuda et al [28,39] have detected the appearance of numerous Pt single crystals on the order of 10-100 nm in the membrane after potential holds at high voltages such as 0.8 V and 1.0 V in air and nitrogen in PEM fuel cells. In addition, the amount of Pt found in the matrix and thus the amount of Pt dissolution has been shown to increase with increasing cathode potentials [19,28,38]. The presence and diffusion of soluble Pt species in fuel cell electrodes is further confirmed by the fact that soluble Pt species have been found in the water collected from the reactant gases exiting the cell [27].…”

Section: Pt Deposition In the Ion-conducting Phasementioning

confidence: 76%

“…Aragane et al [19,38] have first reported the presence of Pt particles in the matrix of PA fuel cells and Pt loss from the cathode, which has provided direct evidence for Pt dissolution from supported Pt nanoparticles in the cathode and reduction of soluble Pt species with permeated hydrogen gas molecules in the membrane. Similarly, Yasuda et al [28,39] have detected the appearance of numerous Pt single crystals on the order of 10-100 nm in the membrane after potential holds at high voltages such as 0.8 V and 1.0 V in air and nitrogen in PEM fuel cells.…”

Section: Pt Deposition In the Ion-conducting Phasementioning

confidence: 98%

“…Aragane et al [19,38] have first analyzed Pt particle size distributions on carbon in the cathode using TEM. It has been shown that Pt nanoparticles coarsen to the same degree from *4 to *7 nm throughout the thickness of the cathode, and that the loading of Pt on carbon decreases in the cathode approaching the cathode-electrolyte (matrix) interface after PA fuel cell operation at 0.7 V for 1,500 h at 190°C (presumably in 99% H 3 PO 4 and air input for the cathode).…”

Section: Changes In the Size And Morphology Of Pt Nanoparticlesmentioning

confidence: 99%

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Instability of Supported Platinum Nanoparticles in Low-Temperature Fuel Cells

et al. 2007

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Section: Pt Deposition In the Ion-conducting Phasementioning

confidence: 76%

Section: Pt Deposition In the Ion-conducting Phasementioning

confidence: 98%

Section: Changes In the Size And Morphology Of Pt Nanoparticlesmentioning

confidence: 99%

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Instability of Supported Platinum Nanoparticles in Low-Temperature Fuel Cells

et al. 2007

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“…A highly hydrophilic surface will be more readily flooded by H 3 PO 4 , and result in higher mass transport resistance. The third challenge is the high dissolution and sintering rates of a catalyst such as Pt due to the high temperature [2,13,[17][18][19][20][21][22]. Ferreira et al had a very thorough review on this topic [17].…”

Section: Introductionmentioning

confidence: 99%

Effect of open circuit voltage on performance and degradation of high temperature PBI–H3PO4 fuel cells

Qi¹,

Buelte²

2006

Journal of Power Sources

105

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“…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. 9 Carbon corrosion.-In parallel to the degradation of platinum particles also corrosion of the carbon support is observed, which leads to loss of contact with the platinum catalyst and therefore to a decrease of the ECSA.…”

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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Effect of operational potential on performance decay rate in a phosphoric acid fuel cell

Cited by 57 publications

References 9 publications

Instability of Supported Platinum Nanoparticles in Low-Temperature Fuel Cells

Instability of Supported Platinum Nanoparticles in Low-Temperature Fuel Cells

Effect of open circuit voltage on performance and degradation of high temperature PBI–H3PO4 fuel cells

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

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