TY - JOUR
T1 - Molecular dynamics simulations of highly concentrated salt solutions
T2 - Structural and transport effects in polymer electrolytes
AU - Forsyth, M.
AU - Payne, V. A.
AU - Ratner, M. A.
AU - de Leeuw, S. W.
AU - Shriver, D. F.
N1 - Funding Information:
This work was supported by the NSF/MRC through Northwestern Grant MRL DMR 8821571, and by the ARO DAAL-03-90-G-0044. M.F. and V.A.P. gratefully acknowledge a Fullbright Postdoctoral Fellowship and an NSF Predoctoral Fellowship, respectively. We are grateful to J.W. Perram and to A. Nitzan for incisive discussions; and to M.D. Todd for graphical advice.
PY - 1992
Y1 - 1992
N2 - Structural, thermodynamic and transport properties have been calculated in concentrated non-aqueous NaI solutions using molecular dynamics simulations. Although the solvent has been represented by a simplistic Stockmayer fluid (spherical particles with point dipoles), the general trends observed are still a useful indication of the behavior of real non-aqueous electrolyte systems. Results indicate that in low dielectric media, significant ion pairing and clustering occurs. Contact ion pairs become more prominent at higher temperatures, independent of the dielectric strength of the solvent. Thermodynamic analysis shows that this temperature behavior is predominantly entropically driven. Calculation of ionic diffusivities and conductivities in the NaI/ether system confirms the clustered nature of the salt, with the conductivities significantly lower than those predicted from the Nernst-Einstein relation. In systems where the solvent-ion interactions increase relative to ion-ion interactions (lower charge or higher solvent dipole moment), less clustering is observed and the transport properties indicate independent motion of the ions, with higher calculated conductivities. The solvent in this system is the most mobile species, in comparison with the polymer electrolytes where the solvent is practically immobile.
AB - Structural, thermodynamic and transport properties have been calculated in concentrated non-aqueous NaI solutions using molecular dynamics simulations. Although the solvent has been represented by a simplistic Stockmayer fluid (spherical particles with point dipoles), the general trends observed are still a useful indication of the behavior of real non-aqueous electrolyte systems. Results indicate that in low dielectric media, significant ion pairing and clustering occurs. Contact ion pairs become more prominent at higher temperatures, independent of the dielectric strength of the solvent. Thermodynamic analysis shows that this temperature behavior is predominantly entropically driven. Calculation of ionic diffusivities and conductivities in the NaI/ether system confirms the clustered nature of the salt, with the conductivities significantly lower than those predicted from the Nernst-Einstein relation. In systems where the solvent-ion interactions increase relative to ion-ion interactions (lower charge or higher solvent dipole moment), less clustering is observed and the transport properties indicate independent motion of the ions, with higher calculated conductivities. The solvent in this system is the most mobile species, in comparison with the polymer electrolytes where the solvent is practically immobile.
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U2 - 10.1016/0167-2738(92)90285-W
DO - 10.1016/0167-2738(92)90285-W
M3 - Article
AN - SCOPUS:0026899859
VL - 53-56
SP - 1011
EP - 1026
JO - Solid State Ionics
JF - Solid State Ionics
SN - 0167-2738
IS - PART 2
ER -