Conductivity-viscosity-structure: unpicking the relationship in an ionic liquid.
The relationships between the ionic mobility, the viscosity, and the atomic-scale structure are investigated in computer simulations of mixtures of LiF and the network glass-forming material BeF(2). The simulations span a wide range of compositions, across which the fluidity of the system changes greatly due to the break-up of the Be-F network by the addition of the LiF. The relationship between the conductivity and viscosity passes from that expected for independently diffusing ions in the dilute mixtures to strongly decoupled Li+ migration through a viscous network at higher concentrations. The transition between these régimes is linked to the changing local and intermediate-scale structure in the melts. The decoupling phenomenon is associated with the appearance of migration channels in the network which leads to cooperative effects in the Li+ migration.
Salanne
Mathieu
M
Université Pierre et Marie Curie-Paris6, CNRS, ESPCI, UMR 7612, laboratoire LI2C, case courrier 51, 4 Place Jussieu, 75252 Paris Cedex 05, France.
Simon
Christian
C
Turq
Pierre
P
Madden
Paul A
PA
D001608:Beryllium / Q000737:chemistry*; D003198:Computer Simulation; D004553:Electric Conductivity; D005459:Fluorides / Q000737:chemistry*; D052578:Ionic Liquids / Q000737:chemistry*; D018020:Lithium Compounds / Q000737:chemistry*; D008958:Models, Molecular; D015394:Molecular Structure; D014783:Viscosity
D052578:Ionic Liquids; D018020:Lithium Compounds; C027651:lithium fluoride; C035982:beryllium fluoride; D001608:Beryllium; D005459:Fluorides