(420e) Computing Electron Transfer Rates for Ethylene Carbonate Reduction with Marcus Theory Using Molecular Simulations
AIChE Annual Meeting
2020 Virtual AIChE Annual Meeting
Engineering Sciences and Fundamentals
Interfacial Phenomena in Electrochemical Systems
Thursday, November 19, 2020 - 9:00am to 9:15am
We combine molecular simulations and Marcus theory formalism to compute rate of ET from a graphitic anode to interfacial EC molecules in the condensed phase.3 This talk demonstrates how to construct the necessary Marcus parabolas from which the reorganization energy, free energy barrier, and free energy of reaction are defined. Further, we also show the configuration dependence on electronic coupling strength between our model graphitic anode and interfacial EC by computing couplings from an ensemble of interfacial structures.
From our constructed Marcus parabolas, we see a large reorganization energy associated with EC reduction, both inner-sphere (internal configurational change) and outer-sphere (solvent response to charge transfer), which implies that both types of fluctuations are important for computing the rate of ET. Lastly, we show how computing the free energy of reaction via changes in intrinsic solvation energy4 allows for the easy comparison of multiple systems.
(1) Peled, E. The Electrochemical Behavior of Alkali and Alkaline Earth Metals in Nonaqueous Battery SystemsâThe Solid Electrolyte Interphase Model. J. Electrochem. Soc. 1979, 126, 2047.
(2) Aurbach, D.; Markovsky, B.; Shechter, A.; Ein-Eli, Y. A Comparative Study of Synthetic Graphite and Li Electrodes in Electrolyte Solutions Based on Ethylene Carbonate-Dimethyl Carbonate Mixtures. J. Electrochem. Soc. 1996, 143, 3809â3820.
(3) Marcus, R. A.; Sutin, N. Electron Transfers in Chemistry and Biology. Biochim. Biophys. Acta 1985, 811, 265â322.
(4) Duignan, T. T.; Baer, M. D.; Schenter, G. K.; Mundy, C. J. Electrostatic Solvation Free Energies of Charged Hard Spheres Using Molecular Dynamics with Density Functional Theory Interactions. J. Chem. Phys. 2017, 147, 161716.