Microfluidic Shape Analysis of Non-spherical Graphite for Li-Ion Batteries via Viscoelastic Particle Focusing

Area of Science:

• Materials Science
• Electrochemistry
• Fluid Dynamics

Background:

• Graphite's size and shape critically influence lithium-ion battery (LIB) performance and electrode slurry rheology.
• Accurate characterization of graphite's dimensions is a persistent challenge in battery manufacturing.

Purpose of the Study:

• To develop and apply a novel method for precise characterization of graphite anode material.
• To investigate the impact of graphite's size and shape on LIB performance and manufacturing.

Main Methods:

• Utilizing viscoelastic particle focusing within a cross-slot microchannel to align graphite particles.
• Employing a planar extensional flow field at the stagnation point for edge-plane alignment.
• Quantifying the edge size and shape of both natural and ball-milled graphite.

Main Results:

• Graphite particles align to reveal their edge plane under the applied flow field.
• Accurate quantification of edge size and shape was achieved for different graphite types.
• Ball-milled graphite exhibits lower circularity and higher aspect ratio, indicating a more plate-like morphology compared to natural graphite.

Conclusions:

• The developed microchannel method enables accurate graphite characterization, crucial for quality control in LIB mass production.
• Understanding graphite morphology's impact on rheology, electrode structure, and electrochemical performance can enhance LIBs.
• This technique facilitates improved quality control for graphite materials used in lithium-ion batteries.