Ru-Embedded Highly Porous Carbon Nanocubes Derived from Metal-Organic Frameworks for Catalyzing Reversible Li₂O₂...

Area of Science:

• Electrochemistry
• Materials Science
• Energy Storage

Background:

• Rechargeable lithium-oxygen batteries (LOBs) offer high energy density but require efficient oxygen catalysts.
• Reversible lithium peroxide (Li2O2) deposition and decomposition are crucial for LOB performance.

Purpose of the Study:

• To develop a novel oxygen catalyst for enhanced LOB performance.
• To investigate the structure-activity relationship of porous carbon-supported catalysts.

Main Methods:

• Synthesis of highly porous carbon nanocubes with a high surface area (up to 1600 m² g⁻¹).
• Anchoring ruthenium (Ru) nanoparticles onto the carbon nanocubes to create an oxygen cathode catalyst.
• Electrochemical testing of the catalyst in LOBs, including charge/discharge cycling and capacity measurements.
• Ex situ and operando characterizations to analyze the catalyst's behavior during operation.

Main Results:

• Achieved a low charge/discharge potential gap of 0.75 V.
• Demonstrated a high total discharge capacity of 17,632 mA h g⁻¹.
• Exhibited excellent cycling performance with 550 cycles at 1000 mA g⁻¹.
• Identified synergistic effects of the porous structure and active sites in reducing overpotentials and parasitic reactions.

Conclusions:

• The developed Ru-anchored porous carbon nanocube catalyst significantly improves LOB performance.
• The catalyst's structure facilitates efficient mass/charge transport and accommodates reaction products.
• This work provides a promising strategy for designing advanced catalysts for high-energy-density batteries.