State of charge indicators for alkaline zinc-air redox flow batteries

Christian Zelger, Michael Süßenbacher, Andreas Laskos, Bernhard Gollas

Publikation: Beitrag in einer FachzeitschriftArtikelForschungBegutachtung

Abstract

Physico-chemical properties of NaOH and KOH electrolytes are studied as possible state of charge indicators for the alkaline zinc-air redox flow battery. In order to predict the available energy of the battery and to prevent degradation as the result of unsuitable operating conditions, its state of charge has to be known. The state of charge is directly related to the composition of the negative electrolyte. A battery charging operation is simulated by electrodepositing zinc on a rotating cylinder electrode from NaOH electrolyte, while the simulation of a discharging operation is accomplished by dissolving ZnO in KOH electrolyte. The refractive index, conductivity, and density of NaOH- and KOH-electrolytes as well as the rest potential of the zinc electrode in these media are measured for different zincate and alkali concentrations at several temperatures. The electrolyte density and electrolyte conductivity are both linearly correlated with the zincate concentration. A linear correlation is found also between the rest potential and the logarithmic concentration term in the Nernst equation for the zinc half-cell reaction. These indicators permit a simple and straightforward monitoring of the state of charge of alkaline zinc-air redox flow batteries.

Originalspracheenglisch
Seiten (von - bis)76-81
Seitenumfang6
FachzeitschriftJournal of power sources
Jahrgang424
DOIs
PublikationsstatusVeröffentlicht - 1 Jun 2019

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    ASJC Scopus subject areas

    • !!Renewable Energy, Sustainability and the Environment
    • !!Energy Engineering and Power Technology
    • !!Physical and Theoretical Chemistry
    • !!Electrical and Electronic Engineering

    Fields of Expertise

    • Advanced Materials Science

    Treatment code (Nähere Zuordnung)

    • Experimental

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