Investigation on the performance of proton exchange membrane water electrolyzer coupled with a catalyst layer pore network model

Abstract

Improvement of performance and cost reduction are urgent issues for proton exchange membrane water electrolyzers (PEMWEs). This study explored ways to improve electrolyzer performance from the perspective of the catalyst layer (CL) microstructures. The pore network model of the CL was established, and the obtained structural, mass transfer and electrochemical parameters were coupled with the macroscale performance model of PEMWE to get the multi-scale performance model. The mass transfer, heat transfer, and electrochemical processes inside the electrolyzer were considered to improve the model's accuracy. The maximum error between the simulated results by this multi-scale performance model and the experimental data was verified to be only 3.1%. The verified model was then used to predict the electrolyzer performance with various cathode/anode catalyst layer (CCL/ACL) microstructures. The predicted results showed that the electrochemical activity surface area affects the performance of PEMWE to a much greater extent than the conductivity. The performance of PEMWE gradually deteriorated as the catalyst particle radius or pore diameter of the CCL/ACL increased by the same degree, and the catalyst particle radius had a relatively more significant impact on the performance of the electrolyzer. Overall, the variation of ACL structure had a more substantial effect on the electrolyzer performance than that of CCL.