Optimization of the zinc oxide reduction in the charging process of zinc-air flow batteries

摘要

In practice, the zinc-air flow batteries are charging by reduction of zinc oxide, dissolved in the battery electrolyte through consuming electrical energy. Later, during the discharge process, the produced zinc reacts with oxygen and releases electrical energy. Thus, the amount of produced zinc in a battery is directly related to the amount of energy storage. The current work aims to maximize the reduction of zinc oxide for a single cell of 100 W zinc-air flow battery by using the Taguchi method. The controlling parameters, which influence the zinc production are charging current, electrolyte concentration (KOH), stirring speed of the electrolyte, and electrolyte temperature. Interestingly, the results show that the temperature of the electrolyte is the most effective parameter of zinc oxide reduction. After that, the charging current density, electrolyte concentration, and stirring speed are the other important parameters, respectively. The results reveal that an optimized set of the controlling parameters could improve the zinc production up to six-fold compared to a badly tuned set of control parameters.