Quantification of the Carbon-Coating Effect on the Interfacial Behavior of Graphite Single Particles

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• Natural graphite (NG) is a common anode material for lithium-ion batteries.
• Improving the interfacial properties of graphite is crucial for enhanced electrochemical performance.

Purpose of the Study:

• To investigate the impact of carbon coating on the interfacial charge transfer resistance of natural graphite.
• To synthesize and characterize carbon-coated natural graphite (NG@C) for high-power anode applications.

Main Methods:

• Synthesized microscale carbon-coated natural graphite (NG@C) using a wet-chemical mixing method with phenolic resin.
• Conducted electrochemical tests on conventional composite electrodes.
• Utilized single-particle measurements to analyze electrochemical parameters like charge transfer resistance (Rct) and exchange current density (i0).

Main Results:

• Carbon-coated natural graphite (NG@C) demonstrated improved rate capability, cycle stability, and kinetic properties compared to uncoated NG.
• Interfacial charge transfer resistance (Rct) decreased from 81-101 Ω cm² (NG) to 49-67 Ω cm² (NG@C).
• Exchange current density (i0) increased from 0.25-0.32 mA cm⁻² (NG) to 0.38-0.52 mA cm⁻² (NG@C).

Conclusions:

• A uniform surface carbon layer on graphite particles significantly enhances the solid-liquid interface and kinetic parameters.
• Carbon coating effectively improves the electrochemical performance of natural graphite, making it suitable for high-power anode materials.
• The study provides quantitative evidence for the benefits of carbon coating in advanced battery materials.