Molecular Level Understanding of the Factors Affecting the Stability of Dimethoxy Benzene Catholyte Candidates from First-Principles Investigations
- Joint Center for Energy Storage Research, ‡Materials Science Division, and §Chemical Sciences and Engineering Division, Argonne National Laboratory, Argonne, Illinois 60439, United States
First-principles simulations are performed to gain molecular level insights into the factors affecting the stability of seven 1,4-dimethoxybenzene (DMB) derivatives. These molecules are potential catholyte candidates for nonaqueous redox flow battery systems. Computations are performed to predict oxidation potentials in various dielectric mediums, intrinsic-reorganization energies, and structural changes of these representative catholyte molecules during the redox process. In order to understand the stability of the DMB-based radical cations, the thermodynamic feasibility of the following reactions is computed using density functional theory: (a) deprotonation, (b) dimerization, (c) hydrolysis, and (d) demethylation. The computations indicate that radical cations of the 2,3-dimethyl and 2,5-dimethyl derivatives are the most stable among the DMB derivatives considered in this study. In the presence of solvents with high-proton solvating ability (water, DMSO, acetonitrile), degradation of cation radical occurring via deprotonation is the most likely mechanism. In the presence of solvents such as propylene carbonate (PC), demethylation was found to be the most likely reaction that causes degradation of radical cations. From the computed enthalpy of activation (Delta H-double dagger) for a demethylation reaction in PC, the 2,5-dimethyl DMB cation radical would exhibit better kinetic stability in comparison to the other candidates. Finally, this investigation suggests that computational studies of structural properties such as redox potentials, reorganization energies, and the computed reaction energetics (deprotonation and demethylation) of charged species can be used to predict the relative stability of a large set of molecules required for the discovery of novel redox active materials for flow battery applications
- Research Organization:
- Argonne National Laboratory (ANL), Argonne, IL (United States)
- Sponsoring Organization:
- USDOE Office of Science (SC), Basic Energy Sciences (BES)
- Grant/Contract Number:
- AC02-06CH11357
- OSTI ID:
- 1259933
- Alternate ID(s):
- OSTI ID: 1352881
- Journal Information:
- Journal of Physical Chemistry. C, Journal Name: Journal of Physical Chemistry. C Vol. 120 Journal Issue: 27; ISSN 1932-7447
- Publisher:
- American Chemical SocietyCopyright Statement
- Country of Publication:
- United States
- Language:
- English
Web of Science
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