Dynamic Charge Redistribution Induced by Atomic Escape for Enhanced Polysulfide Regulation and Sulfur Redox Kinetics

Area of Science:

• Materials Science
• Electrochemistry
• Nanotechnology

Background:

• Sub-nanocatalysts struggle with inconsistent catalytic centers, hindering lithium polysulfide (LiPS) suppression and redox kinetics in batteries.
• Existing methods for creating catalytic centers often result in spatial inconsistencies, limiting their efficiency.

Purpose of the Study:

• To develop a novel strategy for creating high-density, isolated single-atom catalysts with uniform catalytic centers.
• To address the challenges of LiPS shuttling and sluggish redox kinetics in lithium-sulfur batteries.

Main Methods:

• A carbon-confined thermal evolution strategy was employed to convert vanadium clusters (V Cs) into vanadium single atoms (V SAs).
• Density Functional Theory (DFT) calculations were used to investigate the electronic properties and catalytic performance of V SAs and V Cs.
• In-situ characterization techniques were utilized to validate the enhanced polysulfide anchoring and reaction kinetics.

Main Results:

• The developed strategy successfully created high-density, isolated V SAs with uniform catalytic centers.
• V SAs demonstrated superior LiPS adsorption and reduced Li2S nucleation barriers compared to V Cs.
• Batteries incorporating V SAs in separators exhibited high initial capacity (1527 mAh g⁻¹) and ultralong stability (0.047% decay/cycle over 1000 cycles).
• Practical tests showed excellent capacity retention (96% after 100 cycles at 5.2 mg cm⁻² sulfur loading) and high output capacity (1071.9 mAh g⁻¹ in pouch cells).

Conclusions:

• The study establishes a structure-charge density relationship at the atomic level for catalytic materials.
• The developed V SAs offer a universal design principle for advanced catalysts in energy storage applications.
• The findings highlight the significant commercialization potential of this approach for high-performance lithium-sulfur batteries.