123rd General Meeting of the KCS

Type Poster Presentation
Area Electrochemistry
Room No. Exhibition Hall 2
Time 4월 18일 (목요일) 11:00~12:30
Code ELEC.P-437
Subject Time transient electrochemical monitoring of tetraalkylammonium polybromide solid particle formation: observation of ionic liquid-to-solid transitions
Authors Yejin Choi, Jinho Chang*
Department of Chemistry, Hanyang University, Korea
Abstract Energy storage systems (ESSs) using a Br-Br2 redox reaction such as a Zn/Br redox flow battery (RFB) or a redox-enhanced electrochemical capacitor (Redox-EC) suffer from self-discharge reactions resulting in significant coulombic loss. To inhibit the self-discharge, quaternary ammonium (Q+) and tetraalkylammonium (T+) bromide are added to form ionic liquid (QBr2n+1) and solid (TBr3) polybromides during the ESS charging process. The electrochemical formation of liquid QBr2n+1 and its electrochemical properties have been examined. The detailed mechanisms of ionic solid TBr3 formation, however, have not yet been explored. In this article, we analyzed the ionic liquid-to-solid phase transition of TBr3 particles using a time transient electrochemical method. We suggest the formation of ionic solid TBr3 particles via hydrated TBr3 droplets as an intermediate phase, which are generated by electro-oxidation of Br- in an aqueous TBr solution. We found the phase transition time of TBr3 particles is strongly dependent on the chemical structure of T+ and the concentration of TBr in an aqueous solution.
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