Probing Electron Transfer Orbitals Selectively at LiCoO_{2}/C Cathode Interfaces via Positron Annihilation...

Area of Science:

• Materials Science
• Solid State Physics
• Electrochemistry

Background:

• Conductive carbon additives enhance electron transport in lithium-ion battery cathodes, crucial for rapid charging.
• Quantifying the precise contribution of these additives to electron transport remains a significant challenge in battery research.

Purpose of the Study:

• To develop and apply a method for quantifying the electron transport enhancement provided by carbon additives in LiCoO_{2} cathodes.
• To elucidate the nanoscale charge transport pathways within LiCoO_{2}/C composite materials.

Main Methods:

• Utilizing momentum distribution of annihilating electron-positron pairs to probe O 2p orbitals in LiCoO_{2} and 2p_{z} carbon orbitals.
• Performing ab initio modeling of LiCoO_{2} and carbon structures to reproduce experimental momentum distributions.
• Quantifying positron annihilation fractions within carbon structures and spectral contributions of electron transfer orbitals.

Main Results:

• Successfully amplified subtle electron momentum distribution signals originating from carbon π bonds.
• Quantified the fraction of positron annihilation within various carbon structures using theoretical modeling.
• Identified potential charge transport pathways by analyzing electron transfer orbitals in the LiCoO_{2}/C composite.

Conclusions:

• The study demonstrates a novel approach to quantify the role of conductive carbon additives in battery cathodes.
• The findings reveal the nanoscale circuitry responsible for efficient electron transport, offering insights for designing advanced lithium-ion batteries.
• This work bridges experimental observations with theoretical modeling to understand complex charge transport mechanisms.