A Mo₂C-MoP heterostructure enabled catalytic route for high-performance lithium-sulfur batteries

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• Commercialization of lithium-sulfur (Li-S) batteries faces challenges due to polysulfide shuttling and slow conversion kinetics.
• These issues limit the practical application and cycle life of Li-S battery technology.

Purpose of the Study:

• To develop a novel strategy for regulating the polysulfide conversion pathway in Li-S batteries.
• To enhance the electrochemical performance and stability of Li-S batteries by addressing key kinetic limitations.

Main Methods:

• Fabrication of a Mo2C-MoP heterostructure catalyst.
• Investigation of the catalytic mechanism for polysulfide conversion using the heterostructure.
• Construction and electrochemical testing of a sulfur cathode (S/Mo2C-MoP@CNF) utilizing the catalyst.

Main Results:

• The Mo2C-MoP heterostructure effectively catalyzes the cleavage of Li2S6 into LiS3˙ radicals.
• Rapid liquid-phase disproportionation of LiS3˙ radicals facilitates chemical nucleation of Li2S, bypassing slow liquid-solid conversion.
• The S/Mo2C-MoP@CNF cathode achieved a high discharge capacity of 1054.2 mAh g-1 at 0.5C.
• Demonstrated excellent cycle stability with a low capacity fading rate of 0.062% per cycle.

Conclusions:

• The Mo2C-MoP heterostructure provides an effective pathway to overcome kinetic bottlenecks in Li-S batteries.
• This catalytic approach significantly improves discharge capacity and cycle life, paving the way for advanced Li-S battery development.