Synergistic LaCoO₃@Co₃O₄ bifunctional catalyst for efficient oxygen evolution and reduction: achieving low...

Area of Science:

• Materials Science
• Electrochemistry
• Catalysis

Background:

• Lithium-oxygen batteries (LOBs) face challenges with cycle stability and capacity due to slow oxygen reaction kinetics.
• Developing efficient catalysts for oxygen evolution (OER) and reduction (ORR) is crucial for high-performance LOB air cathodes.

Purpose of the Study:

• To synthesize and evaluate metal oxide catalysts for bifunctional OER and ORR activity in LOBs.
• To understand the structure-performance relationship in composite catalysts for enhanced LOBs.

Main Methods:

• Coprecipitation method for synthesizing Co3O4, LaCoO3, and LaCoO3_Co3O4 catalysts.
• Electrochemical evaluation of bifunctional OER/ORR activity in an alkaline electrolyte.
• Structural and electronic characterization using XRD, XPS, and electronic structure investigations.

Main Results:

• The LaCoO3_Co3O4 composite catalyst exhibited superior bifunctional activity with a minimal potential gap (1.14 V) between OER and ORR.
• Exceptional performance was linked to intrinsic activity and optimized atomic-level active sites, not surface area.
• Structural modifications, including lattice oxygen vacancies and optimized Co3+/Co2+ ratio, enhanced catalytic activity.

Conclusions:

• Synergistic structural and electronic modifications in the composite catalyst critically facilitated electron transfer for OER/ORR.
• Qualitative control of active site structure and electronic coupling is key for designing high-performance LOB catalysts.
• The study guides the development of advanced composite oxide catalysts for LOBs.