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Neutral Red and Ferroin as Reversible and Rapid Redox Materials for Redox Flow Batteries
Author(s) -
Hong Jeehoon,
Kim Ketack
Publication year - 2018
Publication title -
chemsuschem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.412
H-Index - 157
eISSN - 1864-564X
pISSN - 1864-5631
DOI - 10.1002/cssc.201800303
Subject(s) - redox , chemistry , potentiometric titration , vanadium , electron transfer , electrochemistry , half reaction , reaction rate constant , redox titration , diffusion , titration , inorganic chemistry , electrode , photochemistry , kinetics , thermodynamics , physics , quantum mechanics
Neutral red and ferroin are used as redox indicators (RINs) in potentiometric titrations. The rapid response and reversibility that are prerequisites for RINs are also desirable properties for the active materials in redox flow batteries (RFBs). This study describes the electrochemical properties of ferroin and neutral red as a redox pair. The rapid reaction rates of the RINs allow a cell to run at a rate of 4 C with 89 % capacity retention after the 100 th cycle. The diffusion coefficients, electrode reaction rates, and solubilities of the RINs were determined. The electron‐transfer rate constants of ferroin and neutral red are 0.11 and 0.027 cm s −1 , respectively, which are greater than those of the components of all‐vanadium and Zn/Br 2 cells.