Unusual ion transport behaviour of ethylammonium nitrate mixed with lithium nitrate

Abstract

The diffusivity of ions and ionic conductivity of ethylammonium nitrate (EAN) mixed with lithium nitrate (LiNO3) has been carried out as a function of Li-salt concentration and temperature. An unusual behavior of ion diffusivities and ionic conductivities of the mixtures are observed over a range of Li-salt concentration and temperature. The diffusivities of EA+ and Li+, as measured by pulsed-field gradient (PFG) nuclear magnetic resonance (NMR) diffusometry, are found to be comparable in the lower temperature range. An overall decrease in the ion diffusivity is observed with an increase in the concentration of LiNO3. A lower degree of dissociation of ionic complexes in the presence lower concentration of the Li-salt (less than 6 mol. %) resulted in lower ionic conductivity. In the higher concentration range of Li-salt the Li+ diffusivity is monotonously decreased with an increase in the concentration. In the lower concentration range, the Li+ diffusivity exceeded the diffusivity of EA+ cation demonstrating the release of Li+ from the associates. Being enclosed between glass plates, the diffusivities of EA+ and Li+ showed peculiarities similar to the earlier observed results for neat nitrate ILs: accelerated diffusivity of cations and reversible alteration of diffusivities under the influence of strong static magnetic field.