Efficient and Stable Proton Exchange Membrane Water Electrolysis Enabled by Stress Optimization

Area of Science:

• Materials Science
• Electrochemistry
• Mechanical Engineering

Background:

• Proton exchange membrane water electrolysis (PEMWE) is crucial for renewable energy storage but faces challenges in efficiency and long-term stability.
• Current PEMWE designs often exhibit uneven stress distribution, negatively affecting anode catalyst layer (ACL) performance and durability.

Purpose of the Study:

• To investigate the critical role of mechanical stress distribution in PEMWE performance.
• To develop and evaluate a novel flow channel design for improved stress management and enhanced PEMWE operation.

Main Methods:

• Comparative analysis of conventional serpentine flow channels (S-FC) and a proposed Ti mesh flow channel (TM-FC) with gradient pores.
• Evaluation of stress distribution, voltage, and degradation rates in PEMWE cells under varying conditions.
• Cross-scale testing of the TM-FC design in electrolyzers up to 100 kW.

Main Results:

• The TM-FC design significantly reduced stress inhomogeneity compared to S-FC.
• PEMWE with TM-FC showed 27 mV lower initial voltage and an 8-fold reduction in voltage degradation rate at 2.0 A/cm².
• TM-FC demonstrated scalability, with only a 20 mV voltage increase after three orders of magnitude scaleup in 100 kW electrolyzers.

Conclusions:

• Mechanical stress distribution is a critical, yet often overlooked, factor in PEMWE efficiency and stability.
• The proposed Ti mesh flow channel effectively mitigates stress inhomogeneity, leading to substantial improvements in PEMWE performance and durability.
• The TM-FC design shows strong potential for industrial application in large-scale PEMWE systems for renewable energy conversion and storage.