Numerical and Mechanistic Analysis of Active Electroconvection Modulation in Polymer Electrolyte Solutions for Enhanced Ion Transport and Energy Distribution

Abstract

Active modulations of charge-selective interfaces are highly emphasized in electrodeposition and liquid batteries, where the overlimiting current response is linked to dendrite formation on battery electrodes and electrochemical energy storage correlated with electroconvection. However, the overlimiting ion transport is poorly understood in electrochemical engineering at present. We perform a global analysis of the flow patterns, energy spectra, instantaneous and statistical morphology of electroconvection flow (ECF) that exists for polymers and surface patterning by high-resolution Poisson–Nernst–Planck–Navier–Stokes (PNP–NS) schemes. The coupling of the patterning mode and elastic field gives rise to new instabilities and mechanism for the current response and energy distribution. Polymer macromolecules exhibit notable active modulation, dividing I-V (current-voltage) curves into several new branches characterized by energy sources or energy sinks. The instantaneous results reveal chaotic multiscale vortices and charge ribbons that separate and merge in a highly irregular manner. In addition, energy spectral densities (SEDs) suggest that the power law exponential decays over narrower spatiotemporal scales. Owing to the distinction from purely electrokinetic instability-induced modes, the patterning dominant mode enhances ion mass transfer and cancels the limiting regime. The relevant results provide comprehensive physical insight into active modulated electroconvection and affect the design of electromembrane platforms.

Keywords: Ion-selective membrane, polymer electrolyte solutions, electroosmotic flow, patterning surface, electrohydrodynamic, vibroelastic fluid.