High performance of zinc-ferrum redox flow battery with Ac-/HAc buffer solution

摘要

A green low-cost redox flow battery using Zn/Zn2+ redox couple in HAc/NaAc medium and Fe2+/Fe3+ redox couple in H2SO4 medium was first proposed and investigated for potential stationary energy storage applications.The presence of HAc/NaAc in the negative electrolyte can keep the pH between 2.0 and 6.0 even when a large amount of H+ ions move into negative electrolyte from positive electrolyte through ion exchange membrane.In the pH range of 2.0-6.0,the chemical reaction of Zn species with H+ species is very insignificant;furthermore,the electroreduction of H+ ion on the negative electrode is significantly suppressed at this pH range.The zinc-ferrum redox flow battery (Zn/Fe RFB) operated within a voltage window of 0.5-2.0 V with a nearly 90％ utilization ratio,and its energy efficiency is around 71.1％ at room temperature.These results show that Zn/Fe RFB is a promising option as a stationary energy storage equipment.