Suppression of electroconvection due to van der Waals attraction of polymer additives towards the metal electrode

TL;DR

This paper demonstrates that van der Waals attraction of polymer additives near electrodes suppresses electroconvection in batteries, thereby increasing the voltage needed to initiate dendrite growth, with implications for battery stability.

Contribution

It introduces a linear stability analysis showing how polymer-induced van der Waals forces inhibit electroconvection in electrolyte solutions.

Findings

Van der Waals forces create a restoring force opposing electroconvective flow.

Polymer additives increase the critical voltage for electroconvection onset.

Suppression of electroconvection can potentially improve battery safety and lifespan.

Abstract

Electroconvection in rechargeable batteries enhances the growth of dendrites at the electrode surface. The addition of low molecular weight polymers to the electrolyte in batteries results in the formation of a thin layer of higher polymer concentration near the electrode. This is due to van der Waals forces of attraction between the metal electrode and the polymers dissolved in the electrolyte. The van der Waals forces act as a restoring body force on the electrolyte and oppose the growth of perturbations. Using linear stability analysis, we show that this force opposes electroconvective flow. This increases the critical voltage required for the onset of electroconvection.