A High Voltage Aqueous Zinc–Organic Hybrid Flow Battery. Issue 25 (17th May 2019) - Park, Minjoon
Abstract: Water‐soluble redox‐active organic molecules have attracted extensive attention as electrical energy storage alternatives to redox‐active metals that are low in abundance and high in cost. Here an aqueous zinc–organic hybrid redox flow battery (RFB) is reported with a positive electrolyte comprising a functionalized 1, 4‐hydroquinone bearing four (dimethylamino)methyl groups dissolved in sulfuric acid. By utilizing a three‐electrolyte, two‐membrane configuration this acidic positive electrolyte is effectively paired with an alkaline negative electrolyte comprising a Zn/[Zn(OH)4 ] 2− redox couple and a hybrid RFB is operated at a high operating voltage of 2.0 V. It is shown that the electrochemical reversibility and kinetics of the organic redox species can be enhanced by an electrocatalyst, leading to a cyclic voltammetry peak separation as low as 35 mV and enabling an enhanced rate capability. Abstract : A high voltage aqueous zinc–organic hybrid flow battery is developed by utilizing a three‐electrolyte, two‐membrane configuration with a high operating voltage of 2.0 V. The acidic positive electrolyte is effectively paired with an alkaline negative electrolyte. The electrochemical reversibility and kinetics of the organic redox species is enhanced by an electrocatalyst.