Direct Probing the Electrical Double Layer at Graphite/Nafion Interface via Depth Profiling APXPS.

Area of Science:

• Electrochemistry
• Materials Science
• Surface Science

Background:

• The electrical double layer (EDL) is critical for electrochemical system performance.
• EDLs at electrode/polyelectrolyte interfaces are complex and challenging to characterize.
• Understanding these interfaces is key to improving efficiency, capacity, and stability.

Purpose of the Study:

• To directly observe and characterize the potential distribution at the electrode-polyelectrolyte interface.
• To investigate the structure and properties of the EDL in these systems.
• To provide methodological advancements for in situ interface studies.

Main Methods:

• Utilized in situ electrochemical cells coupled with ambient pressure X-ray photoelectron spectroscopy (APXPS).
• Constructed a graphite/Nafion electrode/polyelectrolyte interface.
• Performed APXPS measurements under nonpolarizing conditions at various probing depths.

Main Results:

• Successfully observed potential distribution at the electrode-polyelectrolyte interface.
• Analyzed binding energy shifts of F 1s photoelectrons with applied bias.
• Experimental data, simulated by potential distribution models, indicated a 1-3 nm EDL formation.

Conclusions:

• The study successfully characterized the EDL at the electrode/polyelectrolyte interface.
• Provides valuable fundamental data for electrochemical research and development.
• Offers methodological guidance for future in situ APXPS studies of interfaces.