Characterization of organic electrolyte systems by nuclear magnetic resonance and molecular orbital simulation: equilibrium constant and net charge distribution in solvation state

Solvation states of single solvent electrolyte systems of ethylene carbonate (EC), propylene carbonate (PC), dimethyl carbonate (DMC), ehylmethyl carbonate (EMC) and diethyl carbonate (DEC) with LiPF6 were characterized by C-13-NMR solvation shift and molecular orbital (MO) simulation. Dissociation constants and solvation constants were estimated by parameter fitting to solvation shift using a simple equilibrium model, The solvation shifts Delta delta were observed not only at a lower field but also at a higher field due to change of net charge Delta rho in solvent molecules by Li+ attachment. This particular feature of solvation shifts was demonstrated in the molecular orbital simulation as driven by the change of net charge using a 1:1 (Li+:solvent) solvation model. (C) 1997 Elsevier Science S.A.