Numerical investigation on effects of microporous transport layer in polymer electrolyte membrane water electrolyzers

Abstract

The Polymer Electrolyte Membrane Water Electrolyzer (PEMWE) is pivotal for efficient green hydrogen production through electrolysis. Cost is a major barrier to the widespread commercialization of PEMWE. Introducing a microporous layer (MPL) into PEMWE has immense potential to improve its performance, which could eventually reduce the overall cost. This study numerically investigates the effects of MPL on PEMWE performance after thorough validation of the model with recent experimental data. The study considers the role of MPL in liquid, gas, and charge transport, as well as the energy interactions within the system under various operational conditions. The findings indicate that the implementation of MPL in PEMWE improves liquid, gas, and charge transport, especially at higher current densities. Moreover, the study reports that the MPL enhances capillary pressure distribution, liquid water saturation, and the dissolved water content in the porous media. The MPL is found to significantly accelerate electrochemical reaction kinetics by increasing the triple-phase contact area. The findings also highlight the enhancement of gas pressure distribution across PEMWE due to the MPL. Additionally, lower MPL thickness, higher permeability, and increased exchange current densities are favorable for amplifying PEMWE performance. In essence, this study reveals the core mechanisms and interactions of governing parameters that optimize the performance of PEMWE with MPL.