Application of a Coated Film Catalyst Layer Model to a High Temperature Polymer Electrolyte Membrane Fuel Cell with Low Catalyst Loading Produced by Reactive Spray Deposition Technology

Timothy D Myles,Radenka Maric,Siwon Kim,William E Mustain

doi:10.3390/catal5041673

Abstract

In this study, a semi-empirical model is presented that correlates to previously obtained experimental overpotential data for a high temperature polymer electrolyte membrane fuel cell (HT-PEMFC). The goal is to reinforce the understanding of the performance of the cell from a modeling perspective. The HT-PEMFC membrane electrode assemblies (MEAs) were constructed utilizing an 85 wt. % phosphoric acid doped Advent TPS® membranes for the electrolyte and gas diffusion electrodes (GDEs) manufactured by Reactive Spray Deposition Technology (RSDT). MEAs with varying ratios of PTFE binder to carbon support material (I/C ratio) were manufactured and their performance at various operating temperatures was recorded. The semi-empirical model derivation was based on the coated film catalyst layer approach and was calibrated to the experimental data by a least squares method. The behavior of important physical parameters as a function of I/C ratio and operating temperature were explored.

Highlights

Three of the most significant challenges facing the wide commercialization of proton exchange membrane fuel cells (PEMFCs) are: (1) improving catalyst tolerance to impurities [1,2,3,4,5,6]; (2) simplifying water and thermal management schemes [1,2,3,4,6]; and (3) enhancing the kinetics of the oxygen reduction reaction (ORR) at the cathode [1,2,6,7,8]
The model compares to the data very well over the full range of current densities regardless of the ionomer(PTFE)/carbon(Vulcan XC-72R) (I/C) ratio (average normalized root mean square deviation (NRMSD)
Was 0.020 with a standard deviation of 0.004). Detailed discussions of these trends are available in [28] from an experimental point of view and will be briefly summarized here for convenience. It appears that increasing the I/C ratio, up to 0.9, results in an improvement in the overall performance relating to activation overpotential, ohmic losses, and mass transport limiting behavior

Summary

Introduction

Three of the most significant challenges facing the wide commercialization of proton exchange membrane fuel cells (PEMFCs) are: (1) improving catalyst tolerance to impurities [1,2,3,4,5,6];(2) simplifying water and thermal management schemes [1,2,3,4,6]; and (3) enhancing the kinetics of the oxygen reduction reaction (ORR) at the cathode [1,2,6,7,8]. Carbon monoxide adsorption onto the catalyst surface, which greatly reduces cell performance, is not favored. It was found for temperatures above 160 °C that upwards of 3% carbon monoxide in the feed stream could be tolerated [9,10]. The elevated temperature of the HT-PEMFC means that there is a greater thermal gradient between the cell and the environment. This simplifies the balance of plant related to thermal management due to faster heat rejection [2]. Operating without external humidification simplifies balance of plant and implies single phase, gaseous, transport in the gas diffusion layers (GDL)

Methods

Results

Conclusion