Uroš Luin (Author), Matjaž Valant (Author)

Abstract

An electrochemical cycle for the grid energy storage in the redox potential of Fe involves the electrolysis of a highly concentrated aqueous FeCl2 solution yielding solid iron deposits. For the high overall energy efficiency of the cycle, it is crucial to maximize the energy efficiency of the electrolysis process. Here we present a study of the influence of electrolysis parameters on the energy efficiency of such electrolysis, performed in an industrial-type electrolyzer. We studied the conductivity of the FeCl2 solution as a function of concentration and temperature and correlated it with the electrolysis energy efficiency. The deviation from the correlation indicated an important contribution from the conductivity of the ion-exchange membrane. Another important studied parameter was the applied current density. We quantitatively showed how the contribution of the resistance polarization increases with the current density, causing a decrease in overall energy efficiency. The highest energy efficiency of 89 ± 3% was achieved using 2.5 mol L−1 FeCl2 solution at 70 °C and a current density of 0.1 kA m−2. In terms of the energy input per Fe mass, this means 1.88 Wh g−1. The limiting energy input per mass of the Fe deposit was found to be 1.76 Wh g−1.

Keywords

electrolysis;ferrous chloride;iron deposition;energy efficiency;

Data

Language: English
Year of publishing:
Typology: 1.01 - Original Scientific Article
Organization: UNG - University of Nova Gorica
UDC: 620.1/.2
COBISS: 97710851 Link will open in a new window
ISSN: 1432-8488
Views: 973
Downloads: 69
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Other data

URN: URN:SI:UNG
Pages: str. 929-938
Volume: ǂVol. ǂ26
Issue: ǂiss. ǂ4
Chronology: 2022
DOI: 10.1007/s10008-022-05132-y
ID: 14545691