The Multi-Functional Effects of CuS as Modifier to Fabricate Efficient Interlayer for Li-S Batteries

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• The shuttle effect of lithium polysulfides severely limits the performance of lithium-sulfur batteries (LSBs).
• Developing effective strategies to mitigate this effect is crucial for advancing LSB technology.

Purpose of the Study:

• To design and synthesize a novel cathode interlayer for LSBs.
• To suppress the shuttle effect and improve the electrochemical performance and cycling stability of LSBs.

Main Methods:

• Coral-like copper sulfide (CuS) was synthesized and combined with carbon nanotubes (CNTs).
• The CuS/CNTs composite was coated onto a commercial separator to create a cathode interlayer (PE@CuS/CNTs).
• Electrochemical performance, including discharge capacity, cycling stability, and self-discharge, was evaluated.

Main Results:

• The PE@CuS/CNTs interlayer demonstrated efficient physical blocking and chemisorption of polysulfide anions.
• LSBs with the interlayer exhibited a high initial discharge capacity (1242.4 mAh g⁻¹) and excellent long-term cycling stability (568.5 mAh g⁻¹ after 1000 cycles at 2 C).
• The interlayer also showed resistance to self-discharge and favorable performance under high sulfur loading and lean electrolyte conditions.

Conclusions:

• The coral-like CuS/CNTs interlayer effectively mitigates the polysulfide shuttle effect in LSBs.
• This novel interlayer significantly enhances the electrochemical performance, cycling stability, and practical applicability of LSBs.