Ion transport processes in mixtures of 1-methyl-3-pentylimidazolium tetrafluoroborate ([MPI][BF 4]) and lithium tetrafluoroborate (LiBF 4) are characterized using conductivity and pulsed field gradient NMR measurements at various temperatures. The viscosity, ionic conductivity, molar conductivity, and self diffusion coefficient in neat [MPI][BF 4] and LiBF 4-doped [MPI][BF 4] change with temperature following the Vogel-Tamman-Fulcher equation, and the density shows a linear decrease. The ionic conductivity and the self-diffusion coefficient of each ionic specie decrease with increasing concentration of LiBF 4 in LiBF 4-doped [MPI][BF 4]. The correlation between ionic conductivity and viscosity is based on the classical Walden rule, the α values of neat [MPI][BF 4] and LiBF 4-doped [MPI][BF 4] calculated from the slopes of the Walden plots are compared to those calculated from the ratio of activation energies for viscosity and molar conductivity (E a,Λ/E a,η). The comparison of activation energies of the reciprocal of viscosity, the ionic conductivity, and individual ion diffusion against the LiBF 4 concentration is also studied.
|Number of pages||18|
|Journal||International Journal of Electrochemical Science|
|Publication status||Published - 2012 Mar 1|
All Science Journal Classification (ASJC) codes