Ex-situ characterisation of gas diffusion layers for proton exchange membrane fuel cells

Abstract

h i g h l i g h t s < This study focuses on generating important ex-situ GDL parameters. < The paper highlights the various types of commercial GDLs and discusses their characteristic variations. < The paper shows the relationship between several ex-situ GDL parameters. < The study explores the effect of PTFE loading and MPL presence upon the ex-situ characteristics of the GDL. < This study emphasizes the need of parameters optimisation in GDL design and fabrication. a b s t r a c tThis paper presents the first part of a complete ex-situ characterisation of a wide range of commercial Gas Diffusion Layers (GDLs) used in low temperature and high temperature Proton Exchange Membrane (PEM) fuel cells. Physical and electrical characteristics of the GDLs are reported. The results show that the substrate structure has a significant effect on the mechanical and electrical properties of the GDL. Moreover, the Micro Porous Layer (MPL) structure determines the roughness of the surface, and affects the permeability and porosity of the GDL. It was found that the substrate treatment with PTFE affects the GDL characteristics; PTFE loading increases the GDLs hydrophobicity and permeability, however, decreases its overall porosity and resistivity. Adding a MPL to the substrate, results in a decrease in porosity and permeability and an increase in resistivity. The contact resistance of the GDL and the bipolar plate increases when the GDL thickness and PTFE loading are increased. This technical paper shows a close relationship between GDL materials and their physical characteristics and highlights the importance of optimising GDLs for fuel cell applications.

A Critical Review of Modeling Transport Phenomena in Polymer-Electrolyte Fuel Cells

“…For a more detailed model or multi-dimensional approaches, the in-plane and contact resistances are measured independently. 31 The bulk electrical resistance in the relatively thin electrode is negligible.…”

Free Volume of PVA/SSA Proton Exchange Membrane Studied by Positron Annihilation Lifetime Spectroscopy

“…Crossover of methanol, hydrogen, or oxygen gas through the PEM leads to deterioration of the cell performance and degradation of the PEM [2] . Nafion ® membrane is the most popular and commercial used PEM, firstly produced by DuPont in 1960 [3].…”

Effect of Gas Diffusion Layer on La0.8Sr0.2CoO3Bifunctional Electrode for Oxygen Reduction and Evolution Reactions in an Alkaline Solution

“…Waterproofing or PTFE treatment of carbon substrates for GDLs has been used to avoid possible disruption of air transport that happens when water blocks the pores of GDL 19) . Fig.…”

“…Usually, the cell performance of bifunctional electrode for ORR and OER in alkaline solution has been focused on the catalytic activities of materials. There has been little work for the effect of GDL in electrochemical systems using alkaline solution, even though gas 17,19) . In addition, the morphologies of various GDLs were determined using field emission-scanning electron microscopy .…”