Balancing Adsorption and Catalysis via Interfacial Electronic Coupling for High-Performance Room-Temperature Na-S...

Area of Science:

• Materials Science
• Electrochemistry
• Computational Chemistry

Background:

• Room-temperature sodium-sulfur (RT Na-S) batteries are promising for energy storage but suffer from polysulfide shuttling and slow redox kinetics.
• Achieving high energy density and long cycle life requires balancing polysulfide adsorption and catalysis, as per the Sabatier principle.

Purpose of the Study:

• To design a novel carbon-supported ruthenium (C-Ru) structure with interfacial electronic coupling to address the adsorption-catalysis conflict in RT Na-S batteries.
• To investigate the atomic-level mechanisms governing polysulfide conversion within the C-Ru composite using theoretical calculations.

Main Methods:

• Density Functional Theory (DFT) calculations were employed to analyze charge transfer and its effect on polysulfide adsorption and decomposition.
• Geometric and electronic structure analyses were performed to understand the weakening of Na-S bonds at the interface.
• A sponge-like porous carbon-Ru nanocomposite (SPC-Ru) was synthesized based on theoretical insights.

Main Results:

• DFT calculations revealed optimal charge transfer from Ru to carbon, enhancing polysulfide adsorption and sulfur redox kinetics.
• The C-Ru interface significantly reduced the decomposition barrier of Na₂S by weakening Na-S bonds.
• The synthesized SPC-Ru electrode demonstrated excellent electrochemical performance, including high capacity retention over 500 cycles.

Conclusions:

• Interfacial electronic coupling in C-Ru composites effectively reconciles adsorption-catalysis conflicts in RT Na-S batteries.
• The developed SPC-Ru material offers a viable strategy for high-energy-density and long-lifespan sodium-sulfur energy storage systems.