Percolation Characteristics of Conductive Additives for Capacitive Flowable (Semi-Solid) Electrodes.

Area of Science:

• Materials Science
• Electrochemistry
• Rheology

Background:

• Flowable electrodes are crucial for advanced energy storage and capacitive deionization.
• Particle morphology's effect on dispersion and agglomeration in these systems is not well understood.
• Optimizing electrochemical and rheological properties requires understanding particle behavior.

Purpose of the Study:

• To investigate how conductive additive particle morphology influences the electrochemical and rheological performance of capacitive flowable electrodes.
• To determine critical viscosity limits for common carbon additives in slurry formulations.
• To establish correlations between rheological properties and electrochemical performance.

Main Methods:

• Systematic investigation of conductive additive morphology (e.g., graphene, carbon nanotubes, carbon black).
• Measurement of electrical conductivity, viscosity, and thixotropic recovery.
• Evaluation of electrochemical performance, including capacitance.

Main Results:

• Higher aspect ratio particles (graphene, CNTs) exhibited significantly lower viscosity than carbon black at equivalent conductivity.
• Carbon black demonstrated faster agglomeration kinetics and quicker recovery from shear.
• Particle morphology influenced capacitance by up to 40% for suspensions with similar viscosity.

Conclusions:

• Particle morphology is a key determinant of flowable electrode performance.
• A direct correlation between rheological and electrochemical properties was established.
• Guidelines for slurry formulation based on particle packing density can optimize performance across different morphologies.