Mixed Ionic/Electronic Conducting Surface Layers Adsorbed on Colloidal Silica for Flow Battery Applications

Jeffrey J. Richards, Austin D. Scherbarth, Norman J. Wagner, Paul D. Butler*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

6 Scopus citations

Abstract

Slurry based electrodes have shown promise as an energy dense and scalable storage technology for electrochemical flow batteries. Key to their efficient operation is the use of a conductive additive which allows for volumetric charging and discharging of the electrochemically active species contained within the electrodes. Carbon black is commonly used for this purpose due to the relatively low concentrations needed to maintain electrical percolation. While carbon black supplies the desirable electrical properties for the application, it contributes detrimentally to the rheology characteristics of these concentrated suspensions. In this work, we develop a synthesis protocol to produce inorganic oxide particles with electrostatically adsorbed poly(3,4-ethylenedioxithiophene):polystyrenesulfonate (PEDOT:PSS). Using a combination of small angle neutron scattering (SANS), electron microscopy, and thin-film conductivity, we show that the synthesis scheme provides a flexible platform to form conductive PEDOT:PSS-SiO2 nanoparticle dispersions. Based on these measurements, we demonstrate that these particles are stable when dispersed in propylene carbonate. Using a combination of rheology and dielectric spectroscopy, we show that these stable dispersions facilitate electrical percolation at concentrations below their mechanical percolation threshold, and this percolation is maintained under flow. These results demonstrate the potential for strategies which seek to decouple mechanical and electrical percolation to allow for the development of higher performance conductive additives for slurry based flow batteries.

Original languageEnglish (US)
Pages (from-to)24089-24096
Number of pages8
JournalACS Applied Materials and Interfaces
Volume8
Issue number36
DOIs
StatePublished - Sep 14 2016

Keywords

  • composite
  • flow battery
  • nanoparticle
  • rheology
  • small angle neutron scattering

ASJC Scopus subject areas

  • Materials Science(all)

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