Dr. Nayeon Park

postdoctoral researcher

Seoul National University

Nayeon Park is a postdoctoral researcher at the Digital Chemistry Research Center, Korea Research Institute of Chemical Technology (KRICT), and holds a Ph.D. in Chemical and Biological Engineering from Seoul National University.

Her doctoral research established an experimental–numerical framework for time-dependent rheology of lithium-ion battery anode slurries, synthesizing transient tests and flow simulations into a rheological regime map that links shear-rate and time-scale combinations to dominant mechanisms. She also analyzed pulsatile, shear-thinning flows using a Carreau-type model to derive non-Newtonian Womersley correlations for process-relevant unsteady transport.

At KRICT, she is extending this line of work toward data-driven, generalizable soft-glassy rheology by formulating ensemble kinetic models with probabilistic parameterization and Bayesian optimization to capture yielding, aging/rejuvenation, and viscoelastic memory in concentrated energy-materials suspensions. Her broader goal is to bridge rheological characterization with CFD-grade constitutive models that can be deployed directly in manufacturing process design.

Experimental and numerical investigations of time-dependent battery slurry flows

A comprehensive investigation into the time-dependent rheological behavior of lithium-ion battery (LIB) anode slurries is presented to establish a unified framework for predicting unsteady flow under process-relevant conditions. Because these concentrated suspensions develop multiscale microstructural networks (e.g., connectivity mediated by carbon black and polymer-particle interactions), they exhibit thixotropy and viscoelasticity that are not captured by steady-state constitutive models.

The study integrates experimental and numerical analyses. Transient characterization, including flow start-up, cessation, and shear-rate step tests, is employed to disentangle material responses across time scales. The results reveal a clear separation of mechanisms: viscoelastic effects dominate the short-time regime, whereas structural evolution governs long-time behavior. These observations are synthesized into a rheological regime map that links shear-rate and time-scale combinations to the dominant mechanism and, in turn, provides practical criteria for model selection in battery-electrode processing.

On the numerical side, the work examines pulsatile, shear-thinning flows that commonly arise as disturbances induced by pumps or vibrations. Using the Carreau model to represent viscosity and introducing a non-Newtonian Womersley number to quantify the balance between viscous and inertial effects, the analysis produces predictive master curves for flow amplitude and phase lag, enabling efficient assessment without full transient simulations.

This integrated methodology thus supplies both mechanistic understanding of transient non-Newtonian flow and deployable tools for modeling, analysis, and control of LIB slurries, with straightforward extension to other concentrated multiphase systems.