Mathematical modeling and experimental validation of thin low platinum content and functionally graded cathode catalyst layers

• Author / Creator

  Domican, Kailyn P

• Low catalyst content remains a key requirement for the commercialization of polymer electrolyte fuel cells (PEFCs) into the energy, transportation, and material handling sectors. Understanding the fundamental phenomena reducing fuel cell performance at various stages of operation play a major role in PEFC optimization and reducing catalyst content. In this thesis, high performance PEFCs with low to moderate Pt loadings (27 - 112 μgPt/cm2) have been fabricated using inkjet printing. To better understand thin low Pt content electrodes the PEFCs are tested at various back pressures, relative humidity, and oxygen partial pressures. The characterized PEFCs are then simulated using OpenFCST, an open-source FEM based fuel cell simulation framework, to aid in the investigation of key performance limiting phenomena. The simulations are obtained using a macro-homogeneous, non-isothermal MEA model where a multi-step reaction kinetics describes the oxygen reduction reaction. The model is then validated against the experimental Pt loading, ionomer loading, and oxygen partial pressure study. The successfully validated model highlighted key performance limitations between low Pt content and conventional (400 μgPt/cm2) loading electrodes, while also highlighting the possible phenomena dictating ionomer and oxygen partial pressure performance. A mathematical model is also developed allowing the simulation of functionally graded electrodes. The model is then used to aid experimental design. To validate the new model two functionally graded ionomer electrodes are fabricated, characterized, and compared to the simulated results.

• Subjects / Keywords

  • Low loading
  • Finite-element-method
  • Polymer electrolyte fuel cells
  • Open-source
  • Platinum loading
  • Functionally graded
  • Mathematical models
  • Ionomer loading
  • Back pressure
  • Simulations
  • Membrane electrode assembly
  • Oxygen partial pressure
  • Thin electrode

• Graduation date

  Fall 2014

• Type of Item

  Thesis

• Degree

  Master of Science

• DOI

  https://doi.org/10.7939/R3Q09S

• License

  This thesis is made available by the University of Alberta Libraries with permission of the copyright owner solely for non-commercial purposes. This thesis, or any portion thereof, may not otherwise be copied or reproduced without the written consent of the copyright owner, except to the extent permitted by Canadian copyright law.