Exploring the Influence Mechanism of Porous Transport Layer Structure and Type on Performance in Proton Exchange Membrane Electrolyzer

Abstract

The anode porous transport layer (PTL) plays a crucial role in improving the energy density of proton exchange membrane (PEM) electrolyzer. The influence mechanism of PTL structural parameters and types on electrolysis performance has been investigated based on the voltage decomposition method and surface morphology characterization in this study. Among the Ti-Powder PTLs, which have relatively fixed and low porosity of 28%, PTL-1 with pore diameter of 4.5 μm performs the best, whereas PTL-4 with pore diameter of 62 μm shows the highest ohmic and mass transport over-potential. Specifically, the Ti-Fiber PTL exhibits changes in both porosity and pore diameter. PTL-6 with 50% porosity and PTL-8 with 75% porosity demonstrate superior performance. And this article develops an equivalent ohmic resistance model of the catalyst layer (CL) and proposes the concept of “substrate deadband” at the PTL-CL interface from the perspective of reaction interface construction. Based on the comparative evaluation of Ti-Powder PTL and Ti-Fiber PTL, it shows that the latter has a higher potential for performance improvement. Furthermore, the structure of Ti-Fiber PTL has been optimized and the current density has increased by 26.2% @ 2V, indicating a direction for the application and manufacturing of next-generation PTL.