Interstitial Oxygen Acts as Electronic Buffer Stabilizing High-Entropy Alloys for Trifunctional Electrocatalysis

Area of Science:

• Materials Science
• Electrochemistry
• Alloy Design

Background:

• Understanding high-entropy alloys (HEAs) properties requires knowledge of elemental oxygen affinity.
• The formation and stability of oxygen-containing structures in HEAs are not well understood.
• Diverse HEA components complicate synthesis and analysis.

Purpose of the Study:

• To investigate the impact of oxygen doping on HEAs.
• To understand the mechanism behind the enhanced performance and stability of oxygen-doped HEAs (HEA-O).
• To provide insights into designing novel interstitial oxygen-doped HEAs.

Main Methods:

• Experimental synthesis and characterization of O-doped HEAs (HEA-O).
• Density Functional Theory (DFT) simulations.
• Electrochemical testing in electrolyzed water and Zinc-air batteries.

Main Results:

• O-doped HEAs demonstrated outstanding performance and stability (>1600 h) in batteries.
• Chromium's high oxygen affinity facilitates oxygen incorporation into the HEA system.
• Interstitial oxygen atoms buffer electronic interactions, increasing metal element binding energies.
• Oxygen doping lowers the d-band center, enhancing electrochemical activity.
• Increased vacancy formation energies at metal active sites contribute to super stability.

Conclusions:

• Interstitial oxygen doping is a viable strategy to enhance HEA performance and stability.
• The electronic buffering effect of interstitial oxygen is key to improved properties.
• This study offers a new perspective for designing advanced HEAs for energy applications.