Structured Selective Activation for Bubble-Controlled High-Rate Alkaline OER

Area of Science:

• Electrochemistry
• Materials Science
• Chemical Engineering

Background:

• Efficient gas bubble management is crucial for alkaline oxygen evolution electrodes.
• Current scalable and cost-effective designs are limited.
• Interfacial bubble dynamics impact electrode performance.

Purpose of the Study:

• To present an asymmetrically activated nickel-plate electrode for improved gas bubble management.
• To enhance mass transport and mitigate overpotential in alkaline oxygen evolution.
• To demonstrate a scalable strategy for high-performance electrodes.

Main Methods:

• Fabrication via micromilling, polytetrafluoroethylene (PTFE) coating, and electrodeposition of amorphous nickel-iron (NiFe) catalysts.
• Creation of deactivated and activated regions for directional bubble release.
• Utilizing gridded microchannels for electrolyte renewal.

Main Results:

• Achieved 408 mV at 1000 mA cm^-2, mitigating transport overpotential.
• Reached a high electrochemically active surface area (ECSA)-normalized current density of 210 mA cm^-2.
• Demonstrated sustained performance over 100 hours with a monolithic framework, defect-rich catalysts, and stable PTFE coating.

Conclusions:

• The asymmetric electrode design effectively controls interfacial bubble dynamics.
• This strategy provides both high activity and long-term durability for alkaline oxygen evolution.
• The presented work offers a simple and scalable structural solution for advanced electrode design.