DFT calculations in the gas-phase and in conjunction with the polarized continuum model (PCM) will be utilized to predict electrolyte oxidation stability and decomposition pathways that are expected to occur at non-active electrodes. Oxidation stability from DFT calculations will be reported for cyclic and linear carbonates, sulfones, oligoethers and VC in conjunction with a number of lithium salts. DFT calculations indicated that the intrinsic oxidation stability of electrolyte solvents is often significantly reduced as a result of the H-abstraction reaction from the solvent that immediately follows the initial electron removal step (oxidation). Specifically, the initial oxidation step of carbonates, sulfones and oligoethers complexed with LiPF6, LiBF4, LiB(CN)4 anions resulted in the H-abstraction from the solvent by these anions in similar to our initial results.1 Presence of the anion next to the solvent during oxidation also significantly changes barriers and reaction products for carbonates/anions complexes.2 The importance of explicitly treating at least one solvent will be shown for clusters of carbones, alkyl phosphates, sulfones.The second part of the presentation will focus on understanding of ion aggregation and transport properties of liquid electrolytes and SEI components obtained from molecular dynamics (MD) simulations. MD simulation predictions of the Li2EDC conductivity as a function of temperature will be presented for two different ionic packing structures: the crystal-like and amorphous. Similar conductivity and activation energy was found for the crystal-like and amorphous structures was found with the activation energy between 60-70 kJ/mol. Finally, the ion solvation structure and transport through the Li2EDC || EC:DMC(3:7)/LiPF6will be discussed.References 1. O. Borodin and T. R. Jow, ECS Transactions 33 , 77-84 (2011).2. L. Xing, O. Borodin, G. D. Smith and W. Li, J. Phys. Chem. A 115  , 13896-13905 (2011).

Insight into electrolyte stability, decomposition, and transport properties from DFT and MD simulations

246th National Meeting (2013)

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