Electrochemical performance modification of organic catholyte materials by molecular tuning

Abstract

Redox flow batteries (RFBs) are highlighted for large energy storage system, because of cost effective and ease of scalability. Especially, nonaqueous redox flow batteries (NRFBs) are widely studied to overcome problem of low electrochimical window in traditional water based system. Recent NRFB researches are mainly investigating viable redox active material for both electrode, notably, organic redox active materials give great attention to replace inorganic based materials due to environmentally benignancy, structural diversity and chemical tunability, etc. However, existing studies focus on redox site and simple frameworks, research for molecular tuning by functional group is rarely discussed, even though, study for increasing solubility. Molecular tuning by functional group can profoundly affect not only solubility, also electrochemical characteristic. Herein we report 2-phenyl-1,4-naphthoquinone and its derivatives, for organic catholyte of NRFB system. Each derivatives showed different electrochemical performance by position and kind of functional group. Electrochemical performance were characterized with cyclic voltammetry, unique tube type Li metal battery, and theoretical approach by computational method.