Discovering Reactant Supply Pathways at Electrode/PEM Reaction Interfaces Via a Tailored Interface-Visible...

Area of Science:

• Electrochemistry
• Materials Science
• Chemical Engineering

Background:

• Visualizing reactions in porous transport electrode (PTE) and solid polymer electrolyte (SPE) interfaces is crucial for electrochemical energy devices.
• Challenges exist in observing micro-scale reactions and multiphase transport in devices like proton exchange membrane electrolyzer cells (PEMECs).

Purpose of the Study:

• To develop an in situ characterization cell for visualizing micro-scale electrochemical reactions and transport at PTE/SPE interfaces.
• To investigate the impact of water supply on reaction interfaces in PEMECs under varying current densities.

Main Methods:

• Development of an interface-visible characterization cell (IV-CC).
• In situ visualization of reactions and transport phenomena in a practical PEMEC device.
• Analysis of water droplet evolution and gas blockage at the PTE/PEM interface.

Main Results:

• Successfully visualized local gas blockage and micro water droplets at PTE/PEM interfaces in a working PEMEC.
• Identified unconventional reactant supply pathways within proton exchange membranes (PEMs).
• Demonstrated that PEM water supply to reaction sites is significantly influenced by current density.

Conclusions:

• The IV-CC provides critical insights into micro-scale processes in electrochemical devices.
• Understanding these phenomena is key to optimizing reaction interfaces and enhancing mass transport.
• Findings are applicable to improving various electrochemical energy conversion devices, including PEMECs and CO2 reduction electrolyzers.