Characterization of Effective In-Plane Electrical Resistivity of a Gas Diffusion Layer in Polymer Electrolyte Membrane Fuel Cells through Freeze–Thaw Thermal Cycles

Abstract

The electrical property of gas diffusion layers (GDLs) plays a significant role in influencing the overall performance of polymer electrolyte membrane fuel cells (PEMFCs). The electrical degradation performance of GDLs has not been reported sufficiently. Understanding the electrical degradation characteristics of GDLs is vital to better fuel cell performance, higher efficiency, and longer service time. This paper investigated the effective in-plane electrical resistivity of a commercial GDL by considering environmental and assembly conditions similar to those in use for the operation of PEMFCs. The effective in-plane electrical resistivity of the GDL, subjected to a series of freeze−thaw thermal cycles, was characterized to study its progressive electrical degradation with thermal cycles. Experimental results indicated that, under low compressive loads, the effective in-plane electrical resistivity of the commercial GDL showed weak anisotropy, and was greatly influenced by the transformation of carbon fiber connection in the porous layer. In particular, the thermal aging treatment on the GDL through the first 100 freeze−thaw cycles contributed a lot to its in-plane electrical degradation performance.

Keywords

• gas diffusion layer
• polymer electrolyte membrane fuel cells
• effective in-plane electrical resistivity
• electrical degradation
• freeze–thaw thermal cycles