Atomic layer deposition for efficient oxygen evolution reaction at Pt/Ir catalyst layers.

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• Regenerative fuel cells and vanadium-air redox flow batteries require efficient positive electrodes.
• Titanium felt is a common electrode material, but its surface treatment and catalyst deposition are critical.
• Existing methods like dip-coating have limitations in control and efficiency.

Purpose of the Study:

• To directly compare two methods for Ti felt surface treatment and Pt/Ir electrocatalyst deposition.
• To evaluate performance under identical experimental conditions for electrochemical measurements.
• To determine the most effective method for enhancing electrode performance in regenerative fuel cells and vanadium-air redox flow batteries.

Main Methods:

• Dip-coating: Bimetallic catalyst deposition via precursor salt solution followed by thermal decomposition.
• Atomic Layer Deposition (ALD): Post-anodization coating of felts with controlled ultralow noble-metal loadings.
• Electrochemical measurements under identical conditions to compare mass activity and stability.

Main Results:

• ALD method yielded significantly improved mass activity (557 A·g⁻¹ vs. 80 A·g⁻¹ at 0.39 V overpotential) on a noble-metal loading basis.
• ALD demonstrated superior electrochemical stability compared to the dip-coating method.
• ALD enables precise control over catalyst coating, even in narrow pores, with minimal noble metal usage.

Conclusions:

• Atomic Layer Deposition is a more effective method for preparing Ti felt electrodes for regenerative fuel cells and vanadium-air redox flow batteries.
• ALD offers enhanced performance in terms of mass activity and stability, crucial for advanced energy storage systems.
• The study highlights the potential of ALD for reducing noble metal content while improving catalyst efficiency.