Dynamic Mechanical Fatigue Behavior of Polymer Electrolyte Membranes for Fuel Cell Electric Vehicles Using a Gas Pressure-Loaded Blister.

Jun Hyun Lim,Jian Hou,Chang Hyun Lee

doi:10.3390/polym13234177

Abstract

This study reports on an innovative press-loaded blister hybrid system equipped with gas-chromatography (PBS-GC) that is designed to evaluate the mechanical fatigue of two representative types of commercial Nafion membranes under relevant PEMFC operating conditions (e.g., simultaneously controlling temperature and humidity). The influences of various applied pressures (50 kPa, 100 kPa, etc.) and blistering gas types (hydrogen, oxygen, etc.) on the mechanical resistance loss are systematically investigated. The results evidently indicate that hydrogen gas is a more effective blistering gas for inducing dynamic mechanical losses of PEM. The changes in proton conductivity are also measured before and after hydrogen gas pressure-loaded blistering. After performing the mechanical aging test, a decrease in proton conductivity was confirmed, which was also interpreted using small angle X-ray scattering (SAXS) analysis. Finally, an accelerated dynamic mechanical aging test is performed using the homemade PBS-GC system, where the hydrogen permeability rate increases significantly when the membrane is pressure-loaded blistering for 10 min, suggesting notable mechanical fatigue of the PEM. In summary, this PBS-GC system developed in-house clearly demonstrates its capability of screening and characterizing various membrane candidates in a relatively short period of time (<1.5 h at 50 kPa versus 200 h).

Highlights

Fuel cell electric vehicles (FCEVs) are typically powered by polymer electrolyte membrane fuel cells (PEMFCs) that generate electrical energy from electrocatalytic hydrogen reactions [1]
The mechanical resistance of PEMs was tested at various temperatures, relative humidity, and applied pressure
The results show that the loss of mechanical resistance was faster as the applied temperature and load-pressure increased possibly due to the chemical and mechanical degradation of the membranes and high gas mobility

Summary

Introduction

Fuel cell electric vehicles (FCEVs) have recently attracted great attention as a powerful solution to minimize the generation of carbon dioxide as major exhaust gas from automotive vehicles. FCEVs are typically powered by polymer electrolyte membrane fuel cells (PEMFCs) that generate electrical energy from electrocatalytic hydrogen reactions [1]. It is well recognized that the polymer electrolyte membrane (PEM) is the key material for the development of PEMFC system which can ideally possess high electrochemical performances and long lifetime. The PEM materials should carry the protons generated by the hydrogen oxidation reaction at the anode to the cathode, while serving as a good barrier to prevent the mixing of hydrogen and oxygen gases, which should be supplied the anode and cathode sides separately [2,3].

Objectives

Methods

Conclusion