Jump to main content
Jump to site search

Issue 24, 2021
Previous Article Next Article

Resolving electron transfer kinetics in porous electrodes via diffusion-less cyclic voltammetry

Author affiliations

Abstract

Porous electrodes are cornerstones in advanced electrochemical cells. They extend the electrode/electrolyte interface to three dimensions to boost reaction rates with high specific areas. The rate, however, depends on not only the specific area but also the electron transfer kinetics, the lack of characterization of which has hampered the design of better porous electrodes. The kinetics is often inferred from that on a planar electrode made of a similar material to avoid complications from mass transport in pores, despite likely discrepancies originating from structural and compositional differences due to the unique formation processes of the porous electrodes and their morphologies. Here we resolve electron transfer kinetics on commercial carbon felt, a type of indispensable yet poorly understood porous electrode for redox flow batteries, via a method of diffusion-less cyclic voltammetry. In this method, we place an active electrolyte inside the electrode and scan the voltammetry slowly, the results of which can be modelled accurately without invoking Fick's law and analyzed through a dimensionless term to derive the rate of electron transfer from the peak separation. Three RFB-relevant redox couples, Fe(CN)63/4−, Fe3/2+, and VO2+/VO2+, display rates in the range of 10−4 to 10−8 cm s−1, all much lower than those on glassy carbon. We confirm a correlation between the surface composition of the electrode and the reaction rate of VO2+/VO2+, corroborated by polarization curves attained in an all-vanadium RFB. The work offers a much-needed means towards the understanding of reaction mechanisms and better design of porous electrodes for and beyond RFBs.

Graphical abstract: Resolving electron transfer kinetics in porous electrodes via diffusion-less cyclic voltammetry

Back to tab navigation

Supplementary files

Article information


Submitted
19 Apr 2021
Accepted
23 May 2021
First published
24 May 2021

J. Mater. Chem. A, 2021,9, 14025-14031
Article type
Paper

Resolving electron transfer kinetics in porous electrodes via diffusion-less cyclic voltammetry

S. Yang, Y. Li and Q. Chen, J. Mater. Chem. A, 2021, 9, 14025 DOI: 10.1039/D1TA03270D

To request permission to reproduce material from this article, please go to the Copyright Clearance Center request page.

If you are an author contributing to an RSC publication, you do not need to request permission provided correct acknowledgement is given.

If you are the author of this article, you do not need to request permission to reproduce figures and diagrams provided correct acknowledgement is given. If you want to reproduce the whole article in a third-party publication (excluding your thesis/dissertation for which permission is not required) please go to the Copyright Clearance Center request page.

Read more about how to correctly acknowledge RSC content.


Social activity

Search articles by author

Spotlight

Advertisements