Dynamic Amorphous Composite Shells on 3D Printed High-Entropy Alloy Enable Stable and Active High-Rate Seawater...

Area of Science:

• Materials Science
• Electrochemistry
• Surface Engineering

Background:

• Chloride ions in seawater degrade anode stability and reduce oxygen evolution reaction (OER) efficiency.
• This limits high-rate seawater electrolysis for applications like hydrogen production.

Purpose of the Study:

• To engineer a robust and active anode for high-rate seawater OER.
• To investigate the role of amorphous surface engineering on 3D-printed alloys in mitigating chloride corrosion.

Main Methods:

• Selective laser melting (SLM) 3D printing of a NiFeCoCrMn high-entropy alloy.
• Mild anodic acid etching/reprecipitation to form amorphous hydroxide-oxide composites (a-SLMH).
• In situ Raman spectroscopy and ex situ characterizations to study dynamic reconstruction and corrosion suppression.

Main Results:

• The a-SLMH anode demonstrated excellent seawater oxidation performance, reaching 500 mA cm⁻² at 310 mV and 1000 mA cm⁻² at 328 mV overpotentials.
• Maintained 100% O₂ selectivity at 500 mA cm⁻².
• Achieved stable operation for over 500 hours in alkaline natural seawater at 500 mA cm⁻².

Conclusions:

• SLM 3D printing combined with amorphous surface engineering creates highly active and durable anodes for seawater OER.
• The developed anode effectively suppresses chloride attack, enabling efficient and long-term seawater electrolysis.