Superionic Surface Li-Ion Transport in Carbonaceous Materials.

Area of Science:

• Materials Science
• Electrochemistry
• Solid-State Batteries

Background:

• Lithium-ion transport in bulk carbonaceous materials is well-understood.
• Lithium-ion diffusion mechanisms on carbon surfaces remain largely unexplored.
• High surface area carbon materials are crucial for energy storage applications.

Purpose of the Study:

• To investigate ultrafast lithium-ion transport on carbonaceous material surfaces.
• To explore the potential of surface-mediated ion transport in solid-state batteries.
• To develop novel materials for enhanced battery performance and safety.

Main Methods:

• Experimental synthesis and characterization of lithiated Ketjen black (KB).
• Measurement of ionic conductivity at room temperature.
• Theoretical calculations to determine diffusion barriers for surface lithium species.
• Fabrication and testing of solid-state battery components using lithiated KB.

Main Results:

• Observed ionic conductivity of 18.1 mS cm⁻¹ in lithiated KB, exceeding typical solid-state ion conductors.
• Theoretical calculations confirmed low diffusion barriers for surface lithium ions.
• Lithiated KB effectively mitigated lithium dendrite growth when used as an interlayer.
• Lithiated KB demonstrated high performance as a mixed ionic-electronic conductor, enhancing graphite anode capacity retention to ~85% over 300 cycles.

Conclusions:

• A novel ultrafast surface-mediated lithium-ion transport mechanism has been discovered.
• Lithiated KB shows significant promise as an interlayer and component in solid-state batteries.
• This finding opens new avenues for designing advanced solid-state ion conductors and batteries.