Slot Die Coating Rheology in Battery Electrode Slurry Manufacturing
Slot die slurry throughput depends on high-shear thinning during extrusion and rapid low-shear yield stress recovery to prevent edge bead defects.
Oscillatory Strain Sweep
Meaning
Dynamic rheological testing at variable deformation amplitudes and a constant frequency identifies the limits of structured suspension stability. By measuring storage and loss moduli across a range of shear amplitudes, an oscillatory strain sweep locates the transition from elastic behavior to viscous flow. This boundary marks the point where the internal network of polymer chains and particles begins to break down.
Knowing this yield point is essential for predicting how the suspension will perform during high-speed pumping and application.
Structural Evaluation
Low strains preserve the internal network of the sample, allowing for the determination of the linear viscoelastic region. In this region, the storage modulus remains independent of the applied strain, representing the solid-like behavior of the slurry at rest.
Deformation Threshold
Once the strain exceeds a critical limit, the storage modulus drops sharply as the gelled structure breaks apart. This crossover point where the loss modulus exceeds the storage modulus indicates that the material has transitioned into a liquid-like state.
Pumping Transition
Operating below this threshold prevents premature gel breakdown during gentle agitation in storage tanks. In contrast, exceeding this threshold ensures that the slurry flows like a liquid when pumped through the coating system.