Conductive carbon black, as a key functional material, plays an irreplaceable role in new energy, electronic devices, and other fields. Its unique conductivity and stability depend on uniform dispersion in the matrix material. However, due to the large specific surface area and high surface energy of carbon black particles, hard agglomerates easily form between particles through van der Waals forces, severely affecting application performance. Therefore, optimizing conductive carbon black dispersion technology has become a core aspect of improving material performance.
The core challenge in conductive carbon black dispersion stems from its inherent physicochemical properties. Branched aggregates formed by ultrafine particles are prone to further agglomeration, and the compatibility difference between hydrophobic surfaces and polar matrices exacerbates the dispersion difficulty. In critical applications such as lithium batteries, uneven dispersion can lead to the breakage of the conductive network, causing a decrease in battery charge-discharge efficiency of more than 20% and a significant shortening of cycle life. Solving this problem requires a systematic approach from three aspects: material modification, process optimization, and additive selection.
Surface modification is a fundamental means of improving dispersibility. Functional groups can be introduced onto the surface of carbon black through coupling agent coating and polymer grafting, reducing surface energy and enhancing affinity with the matrix. Among these methods, covalent modification with low grafting amounts (≤5wt%) ensures compatibility while avoiding loss of conductivity, making it the preferred solution that balances dispersion and functionality. For solvent-based systems, aryl dispersants adsorb onto the carbon black surface via π–π conjugation, effectively preventing agglomerate regeneration.
Process optimization is crucial for achieving uniform dispersion. Pre-dispersion treatment is particularly important; preparing a high-concentration masterbatch of carbon black and a small amount of matrix material (30–60wt%), followed by dilution, significantly improves dispersion stability. For equipment selection, bead mills (bead diameter 0.3–1.0 mm) are the preferred industrial choice due to their strong shear force; combined with 10–120 minutes of cyclic grinding, the aggregate particle size can be controlled within the target range. Meanwhile, optimizing the feeding sequence is crucial—first, completely dissolve the dispersant in the solvent, then slowly add the carbon black to avoid localized high concentrations and the formation of hard lumps.
Evaluating the dispersion effect requires combining multiple indicators. Besides visually observing the absence of obvious agglomerates, particle size distribution must be detected using laser diffraction, conductivity verified using a four-probe analyzer, and stability assessed through a 72-hour static test. In lithium battery slurry preparation, a qualified dispersion system should have a fineness ≤20μm and uniform, stable resistivity to ensure the integrity of the electrode conductive network.
As new energy technologies develop towards higher energy densities, conductive carbon black dispersion technology is upgrading towards precision and greenness. A comprehensive approach combining material modification, process optimization, and additive synergy can solve the agglomeration problem and maximize its conductivity, providing core support for technological breakthroughs in related industries. In the future, the combination of low-energy dispersion processes and biomass-based carbon black will further expand its application boundaries.
