Shell isolated nanoparticles for enhanced Raman spectroscopy studies in lithium-oxygen cells

Area of Science:

• Electrochemistry
• Materials Science
• Spectroscopy

Background:

• Lithium-oxygen batteries are promising energy storage devices.
• Understanding electrode surface chemistry is crucial for battery performance.
• In situ characterization techniques are needed to study reaction mechanisms.

Purpose of the Study:

• To critically assess Shell Isolated Nanoparticles for Enhanced Raman Spectroscopy (SHINERS) on various electrode substrates.
• To investigate the chemical makeup of surface layers on lithium metal electrodes.
• To elucidate the mechanism of the oxygen reduction reaction on carbon substrates relevant to lithium-oxygen cells.

Main Methods:

• Application of SHINERS technique on lithium metal and carbon electrodes.
• Evaluation of nanoparticle distribution and enhancement factors.
• Electrochemical studies under potential control in non-aqueous electrolytes.

Main Results:

• SHINERS significantly enhanced Raman signals from electrode surfaces.
• A predominant Li₂O-based layer was observed on lithium metal electrodes across different electrolytes.
• The formation of LiO₂, Li₂O₂, and Li₂CO₃ during oxygen reduction on carbon electrodes was identified.

Conclusions:

• SHINERS is an effective technique for in situ surface analysis of battery electrodes.
• The study provides insights into the surface chemistry and reaction mechanisms in lithium-oxygen cells.
• Understanding these surface layers is key to improving lithium-oxygen battery technology.