Durable carbon-coated Li2(S) core-shell spheres for high performance lithium/sulfur cells

Area of Science:

• Materials Science
• Electrochemistry
• Nanotechnology

Background:

• Lithium sulfide (Li2S) possesses high theoretical capacity, making it a promising cathode material.
• Practical application of Li2S is hindered by poor cycle life and rate capability.
• Developing stable Li2S-based cathodes is crucial for advanced energy storage.

Purpose of the Study:

• To synthesize size-controlled lithium sulfide spheres.
• To create stable carbon-coated lithium sulfide core-shell (Li2S@C) particles using chemical vapor deposition (CVD).
• To evaluate the electrochemical performance of the novel Li2S@C cathode material.

Main Methods:

• Synthesis of size-controlled Li2S spheres.
• Chemical Vapor Deposition (CVD) for carbon coating.
• Electrochemical testing of Li2S@C composite cathodes.

Main Results:

• Successfully synthesized Li2S@C core-shell particles with protective and conductive carbon shells.
• Achieved a high initial discharge capacity of 972 mAh g⁻¹ Li2S (1394 mAh g⁻¹ S) at 0.2C.
• Demonstrated stable cycling performance with minimal morphology change after 400 cycles at 0.5C, even with high Li2S content (88 wt%).

Conclusions:

• Carbon-coated Li2S@C core-shell particles significantly improve cycle life and rate capability.
• The developed Li2S@C material shows potential for practical application in high-performance lithium-ion batteries.
• This approach offers a viable strategy for stabilizing high-capacity cathode materials.