Boundary Layer Analysis of Membraneless Electrochemical Cells
Name
Bazant_Boundary layer.pdf
Size
1.14 MB
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Adobe PDF
Checksum (MD5)
e96bd298c4f04e551dd8a0bd8a9a0c8d
Author(s)
Braff, William
Buie, Cullen R.
Bazant, Martin Z.
Date Issued
September 2013
Journal
Journal of the Electrochemical Society
Publisher
Electrochemical Society
Citation
Braff, W. A., C. R. Buie, and M. Z. Bazant. “Boundary Layer Analysis of Membraneless Electrochemical Cells.” Journal of the Electrochemical Society 160, no. 11 (January 1, 2013): A2056–A2063. © 2013 The Electrochemical Society.
Version
Final published version
Abstract
A mathematical theory is presented for the charging and discharging behavior of membraneless electrochemical cells that rely on slow diffusion in laminar flow to separate the half reactions. Ion transport is described by the Nernst-Planck equations for a flowing quasi-neutral electrolyte with heterogeneous Butler-Volmer kinetics. Analytical approximations for the current-voltage relation and the concentration and potential profiles are derived by boundary layer analysis (in the relevant limit of large Peclet numbers) and validated against finite-element numerical solutions. Both Poiseuille and plug flows are considered to describe channels of various geometries, with and without porous flow channels. The tradeoff between power density and reactant crossover and utilization is predicted analytically. The theory is applied to the membrane-less Hydrogen Bromine Laminar Flow Battery and found to accurately predict the experimental and simulated current-voltage data for different flow rates and reactant concentrations, during both charging and discharging. This establishes the utility of the theory to understand and optimize the performance of membrane-less electrochemical flow cells, which could also be extended to other fluidic architectures.
MIT Department
Massachusetts Institute of Technology. Department of Chemical Engineering
Massachusetts Institute of Technology. Department of Mathematics
Massachusetts Institute of Technology. Department of Mechanical Engineering
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Article is made available in accordance with the publisher's policy and may be subject to US copyright law. Please refer to the publisher's site for terms of use.
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DOI of Published Version
https://doi.org/10.1149/2.052311jes
