Coupled In Situ NMR and EPR Studies Reveal the Electron Transfer Rate and Electrolyte Decomposition in Redox Flow Batteries.

ABSTRACT: We report the development of in situ (online) EPR and coupled EPR/NMR methods to study redox flow batteries, which are applied here to investigate the redox-active electrolyte, 2,6-dihydroxyanthraquinone (DHAQ). The radical anion, DHAQ^3-•, formed as a reaction intermediate during the reduction of DHAQ^2-, was detected and its concentration quantified during electrochemical cycling. The fraction of the radical anions was found to be concentration-dependent, the fraction decreasing as the total concentration of DHAQ increases, which we interpret in terms of a competing dimer formation mechanism. Coupling the two techniques-EPR and NMR-enables the rate constant for the electron transfer between DHAQ^3-• and DHAQ^4- anions to be determined

SUBMITTER: Zhao EW 

PROVIDER: S-EPMC7877726 | biostudies-literature | 2021 Feb

REPOSITORIES: biostudies-literature