Higher voltage redox flow batteries with hybrid acid and base electrolytes

Abstract

An organic redox flow battery with hybrid acid and base electrolytes using a single cation exchange membrane has been successfully developed to demonstrate higher operation voltage and higher energy density. This concept of hybrid electrolyte flow battery was able to increase the voltage span of a previously tested quinone flow battery by 300 mV and raise the energy density by four times to reach 27.4 Wh/L. This technique has been successfully implemented in another flow battery system utilizing metal ions, demonstrating the applicability of this technique to other types of redox flow batteries. Furthermore, the suggested flow batteries with hybrid electrolytes have been proposed to be economically advantageous over the systems using a cation-exchange membrane and an anion-exchange membrane simultaneously.