Mo₂C/Co@NC heterointerface engineering toward polysulfide regulation in LiS batteries

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• Lithium-sulfur (LiS) batteries face challenges from the polysulfide shuttle effect and slow redox kinetics.
• These issues limit their practical application and cycle life.

Purpose of the Study:

• To design a multi-functional interlayer to address polysulfide shuttling and enhance redox kinetics in LiS batteries.
• To improve the electrochemical performance and stability of LiS batteries.

Main Methods:

• Synthesized a heterogeneous Mo2C/Co confined by N-doped porous carbon (Mo2C/Co@NC) interlayer via controlled pyrolysis.
• Utilized heterogeneous Mo2C/Co as active centers and a porous NC matrix for electron/ion transport.
• Conducted electrochemical evaluations as an interlayer in LiS battery configurations.

Main Results:

• Achieved a high initial discharge capacity of 874.0 mAh g-1 at 3C.
• Demonstrated excellent cycling stability with capacity retention of 373.3 mAh g-1 after 1000 cycles (0.057%/cycle fading).
• Significantly outperformed LiS batteries without the novel interlayer (0.082%/cycle fading).

Conclusions:

• The Mo2C/Co@NC interlayer effectively immobilizes polysulfides and accelerates their redox transformation.
• Hierarchical porous NC matrix ensures rapid electron/ion transport, boosting battery performance.
• Heterointerface engineering offers a promising strategy for developing practical LiS batteries.