The Influence of Electric Field on Crossover in Redox-Flow Batteries

The Influence of Electric Field on Crossover in Redox-Flow Batteries

TitleThe Influence of Electric Field on Crossover in Redox-Flow Batteries
Publication TypeJournal Article
Year of Publication2016
AuthorsRobert M Darling, Adam Z Weber, Michael C Tucker, Michael L Perry
JournalJournal of the Electrochemical Society
Volume163
Issue1
PaginationA5014 - A5022
Date Published01/2016
ISSN0013-4651
Keywordscation-exchange membranes, cell, electrolytes, mass-transport, nafion membranes, performance, scale energy-storage, transport model, vanadium ions, Water transport
Abstract

Transport of active species through the ion-exchange membrane separating the electrodes in a redox-flow battery is an important source of inefficiency. Migration and electro-osmosis have significant impacts on the crossover of reactive anions, cations, and neutral species. In this paper, these phenomena are theoretically and experimentally explored for commercial cation-exchange membranes. The theoretical analysis indicates that plotting the cumulative Coulombic mismatch between charge and discharge as a function of time can be used to assess crossover rates. The relative importance of migration and electro-osmosis over diffusion is quantified and shown to increase with increasing current density and membrane thickness because the contributions of migration and electro-osmosis to ionic flux are independent of membrane thickness and proportional to current density, while diffusion is inversely proportional to membrane thickness and independent of current density. (C) The Author(s) 2015. Published by ECS. All rights 

DOI10.1149/2.0031601jes
Short TitleJournal of the Electrochemical Society
Refereed DesignationRefereed