Nanoconductive agents, with their excellent conductivity, occupy a core position in batteries, electronic devices, and composite materials. However, the high surface energy at the nanoscale makes them highly susceptible to aggregation, which not only weakens the continuity of the conductive network but also severely affects the performance of end products. Therefore, achieving uniform dispersion of nanoconductive agents is crucial to unlocking their application value.
The dispersion process of nanoconductive agents involves three core stages: wetting, dispersion, and stabilization. The wetting stage requires the dispersion medium to fully penetrate the interparticle spaces, expelling air and preventing residual dry powder clumps that could lead to subsequent agglomeration. The dispersion stage breaks up the agglomerated structure by disrupting the van der Waals forces between particles through external force. The stabilization stage prevents the dispersed particles from re-agglomerating through charge repulsion or physical barriers. These three stages are interconnected; neglecting any stage will lead to dispersion failure.
Current mainstream dispersion technologies can be divided into two main categories: physical dispersion and chemical modification. In physical dispersion, ultrasonic dispersion, leveraging the strong impact force generated by cavitation, can efficiently break up the agglomeration of conductive agents such as carbon nanotubes and carbon black, making it a preferred solution for low-viscosity systems. However, the intensity and time must be controlled to avoid damaging the material morphology. For polymer matrices, the shearing action of a twin-screw extruder can achieve uniform dispersion in the molten state; the dispersion effect and material integrity can be balanced by optimizing temperature and rotation speed. Chemical modification involves adding surfactants or modifying functional groups to reduce particle surface energy and improve compatibility with the dispersion medium. Among these, the type of surfactant has the most significant impact on the dispersion effect.
Dispersion effectiveness is constrained by multiple factors, including the type of dispersant, the amount of conductive agent, and the dispersion time, all of which directly affect the final performance. Experiments show that optimal parameters differ across systems; for example, in some systems, a 1.5% conductive agent content, treated with a specific dispersant, yields the best dispersion effect. Furthermore, post-dispersion stability assessment is indispensable. Methods such as static observation and particle size distribution detection can ensure the stability of the dispersed system throughout its application period.
In high-end fields such as new energy, dispersion quality directly determines product competitiveness. In lithium-ion batteries, uniformly dispersed nano-conductive agents can construct a continuous conductive network, reducing electrode internal resistance and improving charge/discharge efficiency and cycle life. In the dry process of solid-state batteries, optimized dispersion of conductive agents can meet the requirements of solvent-free processing, contributing to the development of high-energy-density devices. With technological iteration, the dispersion process of nano-conductive agents is developing towards high efficiency, greenness, and precise control, providing core support for breakthroughs in the performance of advanced materials.
