A Current-Adaptive Polyoxovanadates Protected Anode for Efficient and Stable Ampere-Level Seawater Electrolysis

Area of Science:

• Electrochemistry
• Materials Science
• Green Chemistry

Background:

• Seawater electrolysis offers a sustainable route for green hydrogen production.
• High-current density (HCD) operation in seawater leads to severe chloride corrosion, challenging anode stability and activity.
• Existing anode catalysts struggle with chloride repulsion under industrially relevant HCD conditions.

Purpose of the Study:

• To develop a corrosion-resistant anode catalyst for efficient and stable seawater electrolysis at HCD.
• To investigate the dynamic chloride repulsion mechanism of the novel catalyst under varying current densities.
• To assess the economic viability of hydrogen production using the developed catalyst system.

Main Methods:

• Synthesis of a cobalt-vanadium-oxide catalyst.
• In situ characterization of catalyst behavior under HCD seawater electrolysis.
• Long-term stability testing of the catalyst and electrolyzer.
• Technoeconomic analysis of hydrogen production cost.

Main Results:

• The cobalt-vanadium-oxide catalyst forms current-adaptive polyoxovanadates (POVs) that enhance chloride repulsion at HCD.
• The catalyst demonstrated exceptional stability, operating for over 5000 hours at 1000 mA cm⁻² with minimal decay.
• An anion exchange membrane electrolyzer using this catalyst achieved 1.64 V at 1000 mA cm⁻² and operated stably for over 1500 hours.
• Hydrogen production cost was projected at $1.17/GGE H₂, surpassing the US Department of Energy target.

Conclusions:

• The novel catalyst exhibits dynamic chloride repulsion, enabling robust performance in HCD seawater electrolysis.
• This breakthrough paves the way for cost-effective and stable green hydrogen production from seawater.
• The developed catalyst system significantly advances the field of electrochemical energy conversion and storage.