Challenges in Scaling Up Testing of Catalyst Coated Membranes for Proton Exchange Membrane Water Electrolyzers

Dehua Hou ¹ Geng Qiao ² Liqiu Liu ¹ Xiaoqiang Zhang ² Yichang Yan ^1* Shangfeng Du ^1*

• ¹ University of Birmingham, Birmingham, United Kingdom
• ² Global Energy Interconnection Research Institute Europe GmbH, Berlin, Baden-Württemberg, Germany

Prior to moving newly developed catalyst-coated membranes (CCMs) into large applications for proton exchange membrane water electrolyzers (PEMWEs), a scaling-up test is essential. However, this usually experiences a large performance drop due to the design challenges faced in the testing cell and assembly with a large active area. This work investigates a series of parameters in assembling the testing cell when scaling up the CCM from 5 cm 2 to 50 cm 2 , including assembling force, gasket thickness, and their combination with different porous transport layers (PTLs). At an optimal assembling construction, a CCM with an active area of 5 cm² achieves a current density of 2.4 A/cm² at 1.8 V when tested in a 50 cm² testing cell. In comparison, the same CCM achieves 2.2 A/cm² when tested in a 5 cm² testing cell. However, when scaling up to a CCM with an active area of 50 cm² , the current density drops to 1.73 A/cm² . The influence mechanisms are then explored with the assembly procedures for further improvement of the testing performance of PEM water electrolyzers.