High performance C/S composite cathodes with conventional carbonate-based electrolytes in Li-S battery

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• Lithium-sulfur (Li-S) batteries offer high theoretical energy density but suffer from poor cycle stability and polysulfide shuttle.
• Conventional carbonate-based electrolytes are typically incompatible with sulfur cathodes due to side reactions.

Purpose of the Study:

• To develop highly stable carbon-sulfur (C/S) composites for advanced Li-S batteries.
• To enable the use of standard carbonate-based electrolytes in C/S battery systems.

Main Methods:

• Fabrication of C/S composites via high-temperature sulfur infusion into micro-mesoporous carbon.
• Solvent cleaning treatment to enhance composite stability.

Main Results:

• The C/S composite cathodes exhibit high Coulombic efficiency and long cycling stability.
• A C/S-50 cathode retained 860 mAh/g after 500 cycles with near 100% Coulombic efficiency.
• Outstanding electrochemical performance was achieved using a standard LiPF6 + EC/DEC electrolyte.

Conclusions:

• The C-S chemical bond is crucial for superior electrochemical properties, improving conductivity and buffering volume changes.
• The C/S composites effectively suppress polysulfide formation and shuttle effects.
• This work significantly advances Li-S battery technology by enabling the use of conventional electrolytes.