Zincate Electrolyte Optimization for the Zinc-Air Redox Flow Battery
Christian Zelger, Bernhard Gollas, Aleksandra Gavrilovic-Wohlmuther, Andreas Laskos
Institut für Chemische Technologie von Materialien
10:00 - 10:20 Thursday 24 October 2013 HS II, Alte Technik Intermittent and difficult-to-predict energy sources, like wind farms and solar plants, have to be transformed into a more predictable power source for the customers. This could be obtained with an energy buffer, like a battery [1]. Due to the low cost, environment-friendliness and wide availability of the active materials the zinc–air redox flow battery is a promising candidate for large scale energy storage [2]. Furthermore, by using the air electrode for one half-cell reaction there is no storage volume needed for the positive active material, leading to an increased energy density of the system.
We present a preliminary study of the influence of electrolyte additives on the zinc deposition from potassium hydroxide and sodium hydroxide electrolytes containing different zincate concentrations for a zinc-air redox flow battery. The zinc deposition has been studied by cyclic voltammetry on a glassy carbon rotating disk electrode and by Rota-Hull cell experiments on brass cylinders at different temperatures and rotation rates. Deposits were characterized by optical microscopy and scanning electron microscopy. A few additives gave dendrite-free and mechanically stable zinc deposits at current densities up to at least 50 mA cm-2. One organic additive also shows good long-term chemical stability under strongly alkaline conditions which is required for this type of application.
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[1] J. P. Meyers, The Electrochemical Society Interface, Fall 2010, 44.
[2] C. Ponce de León et al., Journal of Power Sources, 2006, 160, 716-732
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