Taurine electrografting onto porous electrodes improves redox flow battery performance

24 May 2022, Version 1
This content is a preprint and has not undergone peer review at the time of posting.


The surface properties of porous carbonaceous electrodes govern the performance, durability, and ultimately the cost of redox flow batteries. As prepared, commercially available carbon fiber electrode interfaces suffer from limited kinetic activity and incomplete wettability, fundamentally limiting the performance. Here, we propose electrografting as a versatile and facile technique to enable task-specific functionalization of the ubiquitous carbon fiber-based porous electrodes. We elect to investigate taurine as a model molecule as the sulfonic acid group is anticipated to provide hydrophilic and active interfaces whereas the amine group allowing covalent attachment to the carbon surface would enhance stability. We perform hydrodynamic voltammetry and find enhanced kinetic rates of taurine treated model electrodes and flow cell experiments reveal superior mass-transport properties of taurine treated porous cloth electrodes. Additionally, we perform operando neutron radiography to visualize electrolyte infiltration within the electrode in a flow cell setup and find superior wettability of porous electrodes functionalized with taurine. Electrografting emerges as a promising technique to functionalize three-dimensional porous electrodes for redox flow batteries and other electrochemical technologies for energy conversion and storage.


Porous carbon electrodes
Redox flow batteries
Neutron radiography

Supplementary materials

Supporting Information for Taurine electrografting onto porous electrodes improves redox flow battery performance
Effect of extended cycling during electrografting and its effects on the performance of the flow cells, additional XPS characterization of the treated electrodes and the effect of sonication on the surface groups, Koutecký-Levich plots of the hydrodynamic voltammetry experiments with Iron (III), capacitance plots with cyclic voltammetry, stability tests on treated and untreated electrodes and the influence of extended testing on the total and charge transfer resistances extracted by electrochemical impedance spectroscopy, microscopic characterization of treated flat and porous electrode surfaces and additional experiments to understand the effect of electrochemical cycling on the flow cell performance can be found in this document.


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