Surface Functionalization of Silicon, HOPG, and Graphite Electrodes: Toward an Artificial Solid Electrolyte Interface

Area of Science:

• Materials Science
• Electrochemistry
• Surface Chemistry

Background:

• Silicon and graphite are crucial materials in energy storage.
• Surface functionalization is key to improving electrode performance.
• Current methods face challenges in stability and efficiency.

Purpose of the Study:

• To develop a novel method for functionalizing silicon and graphite surfaces.
• To apply this method to graphite electrodes for lithium-ion batteries.
• To investigate the impact of surface modification on battery performance and stability.

Main Methods:

• Electrografting of diazonium salts with protected alkyne moieties.
• Deprotection using tetrabutylammonium fluoride.
• Thiol-yne click chemistry for layer-by-layer assembly.
• Surface characterization using X-ray photoelectron spectroscopy and time-of-flight secondary ion mass spectrometry.
• Electrochemical evaluation via cyclovoltammetry and galvanostatic measurements.

Main Results:

• Successful functionalization of silicon and highly ordered pyrolytic graphite model surfaces.
• Demonstrated layer-by-layer assembly on functionalized surfaces.
• Modified graphite powder electrodes exhibited altered reduction peaks in the first cycle.
• Reduced and modified decomposition processes of battery components observed.
• Remarkable reduction in irreversible capacity loss of the lithium-ion battery.

Conclusions:

• Electrografting combined with click chemistry provides a versatile route for surface functionalization.
• The developed surface modification effectively enhances the electrochemical performance of graphite electrodes.
• This approach offers a promising strategy for improving the efficiency and stability of lithium-ion batteries.