Orchestrating Site-Specific Redox Catalysis via Dual-Atom Engineering for Enhanced Polysulfide Conversion in...

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• Lithium-sulfur (Li-S) batteries face challenges from polysulfide shuttling and slow redox kinetics.
• Existing electrocatalysts struggle to simultaneously manage sulfur reduction (SRR) and sulfur evolution (SER) reactions.

Purpose of the Study:

• To design an advanced electrocatalyst that decouples and promotes distinct SRR and SER pathways.
• To engineer a site-specific dual-atom catalyst for enhanced Li-S battery performance.

Main Methods:

• Atomic-level engineering to create a Ni-Mo dual-atom catalyst (DAC).
• Experimental characterization and theoretical calculations to understand catalytic mechanisms.
• Application of the Ni-Mo DAC in Li-S battery cells.

Main Results:

• The Ni-Mo DAC exhibits site-specific activity: Ni promotes polysulfide conversion, and Mo facilitates Li2S decomposition.
• Enhanced orbital coupling and electronic reconstruction in the DAC enable coordinated redox modulation.
• The Ni-Mo DAC achieved high rate capacity (770.3 mAh g⁻¹ at 5.0C) and excellent stability (0.033% fade/cycle over 1000 cycles).

Conclusions:

• The Ni-Mo DAC effectively addresses kinetic asymmetry in Li-S electrochemistry.
• This work presents a rational strategy for creating redox-coordinated catalytic interfaces for advanced batteries.
• The catalyst demonstrates superior performance under demanding conditions, including high sulfur loading and wide temperature ranges.