Single-atom Catalytic Materials for Lean-electrolyte Ultrastable Lithium-Sulfur Batteries

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• Lithium-sulfur (Li-S) batteries offer high energy density but suffer from polysulfide shuttling and slow reaction kinetics, limiting their practical use.
• These issues lead to poor rate performance and short cycle life, hindering the development of advanced energy storage solutions.

Purpose of the Study:

• To design single-atom materials that accelerate polysulfide conversion in Li-S batteries.
• To investigate the role of nitrogen sites and single-atom iron in improving battery performance.
• To enhance the rate capability and cycling stability of Li-S batteries.

Main Methods:

• Design and synthesis of single-atom materials with nitrogen anchoring sites.
• Density Functional Theory (DFT) calculations to study reaction mechanisms and energy barriers.
• Fabrication and electrochemical testing of coin-type Li-S batteries.

Main Results:

• Single-atom iron sites effectively anchor polysulfides, mitigating the shuttle effect.
• DFT calculations confirmed reduced energy barriers for electrochemical reactions at single-atom sites.
• The Li-S battery demonstrated a high reversible capacity (1379 mAh g^-1 at 0.1 C) and rate capacity (704 mAh g^-1 at 5 C).
• Excellent cycling stability was observed, with 90% capacity retention after 200 cycles at 0.2 C.
• A low electrolyte dosage/energy density ratio of 5.5 g Ah^-1 was achieved.

Conclusions:

• Single-atom materials, particularly with nitrogen-anchored iron sites, are effective in addressing the challenges of Li-S batteries.
• The accelerated polysulfide conversion leads to significantly improved rate performance and long-term cycling stability.
• This approach represents a promising strategy for developing high-performance Li-S batteries for advanced energy storage.