Synchronously Consolidating Li, Se, S, and C for Robust Li-SeS Batteries.

Area of Science:

• Materials Science
• Electrochemistry
• Nanotechnology

Background:

• Sulfur-based cathodes suffer from volumetric changes and structural degradation due to S-redox involving solvated polysulfides.
• Developing stable and high-performance sulfur cathodes is crucial for next-generation energy storage.

Purpose of the Study:

• To propose a synchronous construction strategy for consolidating Li, Se, S, and C elements into a robust composite cathode.
• To enhance the electrochemical performance and structural integrity of sulfur-based cathodes.

Main Methods:

• A novel paradigm reaction (8Li+2Se+CS2 = 2Li4SeS+C) was employed for synchronous construction.
• The composite material (Li4SeS@C) was characterized using TOF-SIMS and DFT calculations.
• Electrochemical performance was evaluated, including specific capacity and cycling stability.

Main Results:

• The synthesized Li4SeS@C composite exhibits crystalline Li4SeS encapsulated in a carbon nanocage.
• The material demonstrates ultrahigh electrical conductivity, an ultralow activation barrier, and excellent structural integrity.
• Achieved a large specific capacity of 615 mAh g-1 and high capacity retention of 87.3% after 350 cycles at 10 A g-1.

Conclusions:

• The synchronous consolidation design significantly improves the electrochemical performance of S-based cathodes.
• The paradigm reaction offers structural diversity and flexibility for developing advanced chalcogenide cathodes.
• This approach provides a new strategy for creating robust and high-performance sulfur or chalcogenide cathodes.