In Situ Electrochemically Derived Amorphous-Li₂ S for High Performance Li₂ S/Graphite Full Cell

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• High-capacity lithium sulfide (Li₂S) cathodes are crucial for advanced lithium-ion batteries.
• A significant challenge is the high activation energy barrier of Li₂S, limiting its practical utilization.
• Low utilization of Li₂S hinders the development of high-energy-density batteries.

Purpose of the Study:

• To achieve a Li₂S cathode with a zero activation potential barrier.
• To enhance the utilization of Li₂S in full cells.
• To develop a novel strategy for high-energy Li₂S-based battery development.

Main Methods:

• In situ electrochemical conversion of lithium polysulfide (Li₂S₈) catholyte into amorphous Li₂S.
• Fabrication of a Li₂S/graphite full cell.
• Theoretical calculations to understand activation potential differences.

Main Results:

• A Li₂S/graphite full cell with a zero activation potential barrier was successfully constructed.
• The cell demonstrated a high discharge capacity of 1006 mAh g⁻¹, indicating high amorphous Li₂S utilization.
• Achieved a long cycle life of 500 cycles for the Li₂S/graphite full cell.

Conclusions:

• In situ electrochemical conversion effectively eliminates the activation barrier of Li₂S cathodes.
• Amorphous Li₂S exhibits lower lithium extraction energy than crystalline Li₂S, facilitating activation.
• This strategy offers a promising pathway for developing high-energy Li₂S-based full cells.