Effect of surface transport properties on the performance of carbon plastic electrodes for flow battery applications

Xihe Sun, Tewfik Souier, Matteo Chiesa, Anthony Vassallo

Research output: Contribution to journalArticle

8 Citations (Scopus)

Abstract

Due to their high electrical conductivity and corrosion resistance, carbon nanotube (MWNT)-high density polyethylene (HDPE) composites are potential candidates to replace traditional activated carbon electrodes for the next generation of fuel-cells, super capacitors and flow batteries. Electrochemical impedance spectroscopy (EIS) is employed to separate the surface conduction from bulk conduction in 15% HDPE-MWNT and 19% carbon black (CB)-HDPE composites for zinc-bromine flow battery electrodes. While exhibiting superior bulk conductivity, the interfacial conductivity of MWNT-filled composites is lower than that of CB-filled composites. High resolution conductive atomic force microscopy (C-AFM) imaging and current-voltage (I-V) spectroscopy were employed to investigate the sub-surface electronic transport of the composite. Unlike the CB-composite, the fraction of conducting MWNTs near the surface is very low compared to their volume fraction. In addition, the non-linear I-V curves reveal the presence of a tunneling junction between the tip and the polymer-coated MWNTs. The tunneling resistance is as high as 1 GΩ, which strongly affects the electronic/electrochemical transfer at the interface of the electrolyte and the surface of the composite, which is evident in the voltammetric and EIS observations.

Original languageEnglish
Pages (from-to)104-110
Number of pages7
JournalElectrochimica Acta
Volume148
DOIs
Publication statusPublished - Dec 1 2014

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Keywords

  • Carbon
  • Composites
  • Conductivity
  • EIS
  • Electrodes

ASJC Scopus subject areas

  • Chemical Engineering(all)
  • Electrochemistry

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