The Importance of the Design of Porous Transport Layers: Unveiling the Interplay Between Structure, Mechanics, and Electrochemistry in Anion Exchange Membrane Water Electrolysis

Abstract

The global drive for sustainable energy solutions intensified interest in anion exchange membrane water electrolysis (AEMWE), as a promising hydrogen production pathway, leveraging renewable energy sources. However, widespread adoption is hindered by the high cost and non-optimised design of crucial components, such as porous transport layers (PTL) and flow fields. This study comprehensively investigates the interplay between structure, mechanics, and electrochemical performance of a low-cost knitted wire mesh PTL, focusing on its potential to enhance cell assembly and operation. Electrochemical characterisation was performed on a single 4 cm² cell, using 1 M KOH at 60°C. Knitted wire mesh PTL, characterised by approximately 70% porosity, 2 mm thickness, and 1.098 tortuosity, delivered a 33% improvement in current density compared to the standard cell configuration. Introducing a knitted PTL interlayer reduced cell voltage by 74 mV at 2 A cm⁻² by improving compression force distribution across the active area, enhancing gas transport and maintaining optimal electrical and thermal conductivity. These findings highlight the significant potential of innovative PTL designs in AEMWE to improve mechanical and operational efficiency without increasing the cost.

Keywords

anion exchange membrane water electrolysis / anode / design / mesh / porous transport layers

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