Evaluation of Cell Performance and Durability for Cathode Catalysts (Platinum Supported on Carbon Blacks or Conducting Ceramic Nanoparticles) During Simulated Fuel Cell Vehicle Operation: Start-Up/Shutdown Cycles and Load Cycles

Abstract

We summarized investigations on the evaluation of cell performance and durability for cathode catalysts on two types of supports, carbon blacks (CBs) and conducting ceramic nanoparticles, during simulated fuel cell vehicle (FCV) operation, including start-up/shutdown (SU/SD) cycles and load cycles. In cathode catalyst layers (CLs) using Pt supported on CBs (Pt/CBs), the effects of graphitized CB (GCB) and Pt nanoparticle size, as well as its dispersion state on the GCB, were investigated on both the performance and durability. The negative effects of the interim cyclic voltammetric measurements on the Pt/CB catalyst degradation during SU/SD cycling evaluation, which led to an overestimation of the degradation process, were also suggested. We found that catalyst degradation occurred not only in the outlet region but also in the inlet region during the gas-exchange SU. Degradation of CBs during a hydrogen passivation SU/SD process was found to decrease but still to occur, due to local cells arising from nonuniform distributions of ionomer and Pt particles. The effects of load cycle conditions, which involved open circuit and load holding times, and variations of current density, and humidity, on the durability of the cathode were also investigated. The buildup of Pt oxides at higher potentials during open circuit and re-reduction at lower potentials during high current density operation led to accelerated degradation; these conditions have relevance to ordinary operation with drastic load changes. For the intrinsic improvement of SU/SD durability, we synthesized conducting ceramic nanoparticles. The durability of the cathode CLs, using Pt supported on conducting ceramic nanoparticles with a fused-aggregate network structure, was superior to that of Pt/GCB. We also proposed that the cathode CL degradation can be mitigated by the use of ceramic nanoparticles in the anode because of the significant reduction of the reverse current due to the high resistivity in the air, termed the “atmospheric resistive switching mechanism” (ARSM).

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Title
Evaluation of Cell Performance and Durability for Cathode Catalysts (Platinum Supported on Carbon Blacks or Conducting Ceramic Nanoparticles) During Simulated Fuel Cell Vehicle Operation: Start-Up/Shutdown Cycles and Load Cycles
Book Title
Nanostructured Materials for Next-Generation Energy Storage and Conversion
Book DOI
10.1007/978-3-662-56364-9
Chapter DOI
10.1007/978-3-662-56364-9_3
Part of
Volume
Editors
  • Fan Li Send Email (1)
  • Sajid Bashir Send Email (2)
  • Jingbo Louise Liu Send Email (3)
  • Editor Affiliation
  • 1 Beijing Key Laboratory for Catalysis and Separation, Department of Chemistry and Chemical Engineering College of Environmental and Energy Engineering, Beijing University of Technology, Beijing, China
  • 2 Department of Chemistry, Texas A&M University-Kingsville, Kingsville, TX, USA
  • 3 Department of Chemistry, Texas A&M University-Kingsville, Kingsville, TX, USA
  • Authors
  • Makoto Uchida Send Email (4)
  • Katsuyoshi Kakinuma Send Email (4)
  • Akihiro Iiyama Send Email (4)
  • Author Affiliation
  • 4 Fuel Cell Nanomaterials Center, University of Yamanashi, Kofu, Yamanashi, Japan
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