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A Protocol for Electrochemical Evaluations and State of Charge Diagnostics of a Symmetric Organic Redox Flow Battery
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Membrane-Electrolyte System Approach to Understanding Ionic Conductivity and Crossover in Alkaline Flow Cells
Thomas Y George1, Isabelle C Thomas1,2, Naphtal O Haya3
1Harvard John A. Paulson School of Engineering and Applied Sciences, Cambridge, Massachusetts 02138, United States.
ACS Applied Materials & Interfaces
|December 5, 2023
Summary
Membrane pretreatment in alkaline flow batteries significantly impacts ferricyanide crossover, affecting conductivity. A new
Area of Science:
- Electrochemistry
- Materials Science
Background:
- Membrane transport properties are critical for electrochemical devices.
- Electrolyte composition and concentration influence membrane performance.
Purpose of the Study:
- To investigate membrane conductivity and ferricyanide crossover in alkaline flow batteries.
- To analyze the effect of electrolyte concentration on membrane conductivity.
- To introduce a new metric, the membrane penalty.
Main Methods:
- Studied Nafion and E-620 membranes in alkaline flow battery electrolytes.
- Measured conductivity and ferricyanide crossover.
- Investigated the influence of electrolyte mass fraction and ion concentration.
Main Results:
- Undetectable ferricyanide crossover for as-received Nafion and E-620 after ion exchange.
- High ferricyanide permeability for pretreated Nafion.
- Increasing electrolyte concentration does not always increase membrane conductivity.
Conclusions:
- Membrane pretreatment significantly affects performance in alkaline flow batteries.
- The 'membrane penalty' metric quantifies the trade-off between conductivity and ion transport.
- Recommendations are provided for membrane selection and use in flow cells and electrochemical reactors.
Keywords:
Nafionconductivitycrossoverelectrolyteequilibriumion-exchange membraneredox flow batterysolubilityMore Related Videos
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