A Ti₃C₂T_x-Based Composite as Separator Coating for Stable Li-S Batteries

Area of Science:

• Materials Science
• Electrochemistry
• Nanotechnology

Background:

• Lithium-sulfur (Li-S) batteries offer high theoretical energy density but suffer from polysulfide shuttling and poor cycling stability.
• Separator modification is a key strategy to mitigate these issues and improve battery performance.

Purpose of the Study:

• To develop and evaluate a novel nitrogen-doped MXene carbon nanosheet-nickel (N-M@CNi) composite as a separator coating for Li-S batteries.
• To enhance sulfur utilization, high-rate capability, and long-term cycling stability of Li-S cells.

Main Methods:

• N-M@CNi powder was synthesized using electrostatic attraction and annealing.
• Characterization included TEM, SEM, Raman, XRD, XPS, and nitrogen adsorption-desorption.
• The N-M@CNi material was applied as a separator coating in Li-S battery cells.

Main Results:

• The N-M@CNi coating exhibited strong lithium polysulfide (LiPS) adsorption and high electrical conductivity.
• Li-S cells with the modified separator showed improved sulfur utilization and high-rate performance.
• Exceptional cycling stability was achieved, with a capacity decay rate of 0.043% at a high sulfur loading of 3.18 mg cm⁻² and 95.8% capacity retention.

Conclusions:

• The N-M@CNi modified separator effectively suppresses polysulfide shuttling and enhances Li-S battery performance.
• This study presents a viable approach for developing advanced separator materials for stable and high-performance Li-S batteries.