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Rational Development of Neutral Aqueous Electrolytes for Zinc–Air Batteries

Rational Development of Neutral Aqueous Electrolytes for Zinc–Air Batteries

Category
Journal publication
Abstract
Neutral aqueous electrolytes have been shown to extend both the calendar life and cycling stability of secondary zinc–air batteries (ZABs). Despite this promise, there are currently no modeling studies investigating the performance of neutral ZABs. Traditional continuum models are numerically insufficient to simulate the dynamic behavior of these complex systems because of the rapid, orders‐of‐magnitude concentration shifts that occur. In this work, we present a novel framework for modeling the cell‐level performance of pH‐buffered aqueous electrolytes. We apply our model to conduct the first continuum‐scale simulation of secondary ZABs using aqueous ZnCl2–NH4Cl as electrolyte. We first use our model to interpret the results of two recent experimental studies of neutral ZABs, showing that the stability of the pH value is a significant factor in cell performance. We then optimize the composition of the electrolyte and the design of the cell considering factors including pH stability, final discharge product, and overall energy density. Our simulations predict that the effectiveness of the pH buffer is limited by slow mass transport and that chlorine‐containing solids may precipitate in addition to ZnO.
Client
  • EC/H2020 / ZAS (Grant No. 646186)
  • EC/H2020 / ZAS (GRANT NO. 646186)
Language
English
Author(s)
Affiliation
  • SINTEF Industry / Sustainable Energy Technology
Year
2017
Published in
ChemSusChem
ISSN
1864-5631
Publisher
Wiley - VCH Verlag GmbH
Volume
23
Page(s)
4735 - 4747