Cycle behaviour of hydrogen bromine redox flow battery cells with bromine complexing agents

JOURNAL OF POWER SOURCES

卷:495

Article

Kuettinger, Michael^1,2  Brunetaud, Ruben¹  Wlodarczyk, Jakub K.³  Fischer, Peter¹  Tuebke, Jens^1,2 

[1] Fraunhofer Inst Chem Technol ICT, Dept Appl Electrochem, Joseph von Fraunhofer Str, D-76327 Pfinztal, Germany

[2] Karlsruhe Inst Technol KIT, Inst Mech Proc Engn & Mech, Str Forum 8, D-76131 Karlsruhe, Germany

[3] Zurich Univ Appl Sci ZHAW, Inst Computat Phys ICP, Wildbachstr 21, CH-8400 Winterthur, Switzerland

关键词: Stationary energy storage;    Redox flow battery;    Bromine;    Safety;    Bromine complexation;    Cell performance;   

DOI  :  10.1016/j.jpowsour.2021.229820

来源: Elsevier

【 摘 要 】

Bromine complexing agents (BCA) are used to improve the safety of aqueous bromine electrolytes versus bromine outgassing in bromine electrolytes. In this work, cycling performance of hydrogen-bromine redox flow battery cells with 1-ethylpyridin-1-ium bromide ([C2Py]Br) as BCA in a bromine electrolyte with a theoretical capacity of 179.6 A h L-1 is investigated for the first time. The BCA leads to increased ohmic overvoltages. One cause of the ohmic drop can be attributed to [C2Py]+ cation interaction with the perfluorosulfonic acid (PFSA) membrane, which results in a drop of its conductivity. The BCA also interacts with bromine in the cell, by forming a non-aqueous fused salt second phase which exhibits a ten times lower conductivity compared to the aqueous electrolyte. A steep rise in cell voltage at the beginning of the charge curve followed by a regeneration of the cell voltage is attributed to this effect. Electrolyte crossover leads to an accumulation of [C2Py]+ in the electrolyte solution and intensifies both adverse processes. Under this condition only 30% of the theoretical electrolyte capacity of 179.6 A h L-1 is available under long term cycle conditions. However, electrolyte capacity is high enough to compete with other flow battery technologies.

【 授权许可】

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