Meaning
Particle size distribution analysis of powders and suspensions utilizes the spatial distribution of scattered light to determine particle dimensions. The technique of laser diffraction measures the angle and intensity of light scattered by a stream of particles as they pass through a collimated beam. Larger particles scatter light at narrow angles with high intensity, whereas smaller particles scatter light at wider angles with lower intensity.
This measurement represents the industry standard for characterizing active battery materials. This size profile is critical because it directly influences both slurry viscosity and the packing density of the electrode coating.
Physical Principle
The mathematical interpretation of the scattering data relies on either the Mie theory or the Fraunhofer approximation. When applying laser diffraction, the instrument calculates the volume-equivalent sphere diameter of the particles based on their scattering patterns. Mie theory requires knowledge of the complex refractive index of both the sample and the suspending medium.
This approach provides accurate results for particles across a wide size range.
Sample Dispersion
Ensuring that the powder is fully dispersed before analysis is essential for obtaining a representative size distribution. In wet laser diffraction measurements, surfactant chemicals or ultrasonic agitation are applied to break up agglomerates within the liquid carrier. For dry measurements, a pressurized air stream disperses the dry powder through the measurement zone.
Industrial Integration
Quality control laboratories use these size measurements to monitor the grinding and synthesis of electrode materials. Changes in the particle size distribution of the starting powder can affect slurry viscosity and coating thickness during cell manufacturing. Automated inline systems utilize this analysis to adjust milling equipment in real-time, reducing waste.
