Impacts of Carbon Corrosion on Cell Performance Decay

Chizawa, Hiroshi; Ogami, Yasuji; Naka, Hiroshi; Matsunaga, Atsushi; Aoki, Nobuo; Aoki, Tsutomu; Tanaka, Kiyofumi

doi:10.1149/1.2781011

Cited by 18 publications

(9 citation statements)

References 5 publications

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“…This phenomenon enhances flooding of the cathode catalyst layer and causes gradual potential decay in long-term operation (> 10,000 h) for use in stationary cogeneration systems (15).…”

Section: Corrosion Of Carbon Support At the Cathodementioning

confidence: 99%

“…Even under normal operation conditions, the surface of carbon support is gradually oxidized, which leaves oxygen-containing functional groups on the surface and increases the hydrophilicity of the support. This phenomenon enhances flooding of the cathode catalyst layer and causes gradual potential decay in long-term operation (> 10,000 h) for use in stationary cogeneration systems (15).…”

Section: Degradation Of Cathode Catalystsmentioning

confidence: 99%

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Durability of Electrocatalysts in Polymer Electrolyte Fuel Cells

Inaba

2009

ECS Trans.

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Durability of electrocatalysts in polymer electrolyte fuel cells has been a major critical issue for commercialization of electric vehicles and stationary cogeneration systems. Though various methods mitigation have been proposed and the durability of fuel cell stacks has been greatly improved, further improvement of durability is needed for use in automotive applications. Here degradation phenomena of electrocatalysts for the cathode and the anode in PEFCs are reviewed and the mechanisms for degradation are discussed.

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“…This phenomenon enhances flooding of the cathode catalyst layer and causes gradual potential decay in long-term operation (> 10,000 h) for use in stationary cogeneration systems (15).…”

Section: Corrosion Of Carbon Support At the Cathodementioning

confidence: 99%

Section: Degradation Of Cathode Catalystsmentioning

confidence: 99%

Durability of Electrocatalysts in Polymer Electrolyte Fuel Cells

Inaba

2009

ECS Trans.

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“…1 Motivated by the need to realize this long-term durability goal, many researchers have provided valuable insights into PEM fuel cell degradation (ageing) through long-term durability and accelerated degradation experiments. [2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19] Cleghorn et al 16 performed a continuous PEM fuel cell long-term durability test over a duration of 26,300 hours. At an operating current density of 0.8 A/cm 2 , they detected a performance reduction rate between 4 and 6 μV/h.…”

mentioning

confidence: 99%

Microporous Layer Degradation in Polymer Electrolyte Membrane Fuel Cells

Hang

George

Gao

et al. 2018

J. Electrochem. Soc.

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In this work, microporous layer (MPL) degradation was investigated through the characterization of polymer electrolyte membrane (PEM) fuel cell performance and in situ liquid water visualizations. While both the MPL and carbon fiber substrate underwent ex situ carbon corrosion-based degradation, the degradation of the MPL has the most significant impact on the electrochemical performance and the liquid water distribution within the operating PEM fuel cell. Specifically, MPL degradation resulted in larger quantities of liquid water accumulation within the gas diffusion layer (GDL), and we attributed this accumulation to the loss of MPL hydrophobicity caused by the carbon corrosion-based degradation process. The increased liquid water accumulation led to increased mass transport resistances and performance losses at high operating current densities (> 1.5 A/cm 2 ). With increasing current density, the liquid water saturation profile converged to an upper threshold within GDLs with MPLs, whereas an upper liquid water saturation threshold was not observed for GDLs without MPLs. Predictions of long-term performance characteristics of PEM fuel cells should be informed by the proneness of the MPL to carbon corrosion degradation.

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“…An increase in the activation polarization by Pt nanoparticle growth occurs from the primary stage in the decay of ORR performance, and that of the diffusion polarization by carbon corrosion occurs from the rather later stage of the catalyst degradation. 29 The results of Fig. 11 and 13 show the structures and electronic states of Pt nanoparticles on KB and AB in equilibrium at each potential under the XAFS measurement conditions in the voltage up and down operations every 0.2 V. The ORR activity may be related to the rate constants for elementary steps in the ORR process on the Pt surface, involving charging-discharging, Pt-O bonding/ dissociation and Pt-Pt dissociation/re-bonding, which can be determined by time-resolved XAFS in rapid voltage-controlled ORR processes.…”

Section: Electrochemical Characterization Of Pt/c Catalysts In Meamentioning

confidence: 99%

Performance and durability of Pt/C cathode catalysts with different kinds of carbons for polymer electrolyte fuel cells characterized by electrochemical and in situ XAFS techniques

Nagasawa

Takao

Higashi

et al. 2014

Phys. Chem. Chem. Phys.

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The electrochemical activity and durability of Pt nanoparticles on different kinds of carbon supports in oxygen reduction reactions (ORR) were investigated using rotating disc electrodes (RDE) and the membrane electrode assemblies (MEA) of polymer electrolyte fuel cells (PEFC). The mass activity of Pt/C catalysts (ORR activity per 1 mg of Pt) at the RDE decreased, according to the type of carbon support, in the following order; Ketjenblack (KB) > acetylene black (AB) > graphene > multiwall carbon nanotube (MW-CNT) > carbon black (CB), whereas the average size of the Pt nanoparticles and the surface specific activity (ORR activity per electrochemical surface area) did not vary significantly between these carbon supports. These results indicate that the different mass activities of the Pt/C catalysts may originate from the differences in the fraction of Pt on the carbon supports which is available for utilization. The durability of the MEAs of the top two active catalysts Pt/KB and Pt/AB among the five catalysts was examined based on ORR performance, TEM and in situ XAFS. It was found that the performance of the Pt/KB cathode catalyst in PEFC MEA decreased significantly over 500 accelerated durability test (ADT) cycles, whereas the performance of the Pt/AB cathode catalyst in PEFC MEA did not decrease significantly during 500 ADT cycles, it was also found that the Pt/AB possesses 8 times higher durability compared with the Pt/KB. In situ Pt LIII-edge XAFS data in the ADT cycles and stepwise potential operations revealed the different oxidation-reduction behaviors of the Pt nanoparticles on the KB and AB supports. The Pt/KB was oxidized to form surface PtO layers more easily than the Pt/AB in the increasing potential operation from 0.4 VRHE to 1.4 VRHE, and the surface PtO layers of the Pt/AB were reduced to the metallic Pt state more readily than those of the Pt/KB in the decreasing potential operation from 1.4 VRHE to 0.4 VRHE. The XAFS analysis for the Pt valences and the coordination numbers of Pt-O and Pt-Pt demonstrated that the Pt/AB catalyst is more durable than the Pt/KB catalyst in PEFC MEAs.

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Impacts of Carbon Corrosion on Cell Performance Decay

Cited by 18 publications

References 5 publications

Durability of Electrocatalysts in Polymer Electrolyte Fuel Cells

Durability of Electrocatalysts in Polymer Electrolyte Fuel Cells

Microporous Layer Degradation in Polymer Electrolyte Membrane Fuel Cells

Performance and durability of Pt/C cathode catalysts with different kinds of carbons for polymer electrolyte fuel cells characterized by electrochemical and in situ XAFS techniques

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