Abstract
Deviations from the Nernst–Einstein relation are commonly attributed to ion–ion correlation and ion pairing. Despite the fact that these deviations can be quantified by either experimental measurements or molecular dynamics simulations, there is no rule of thumb to tell the extent of deviations. Here, we show that deviations from the Nernst–Einstein relation are proportional to the inverse viscosity by exploring the finite-size effect on transport properties under periodic boundary conditions. This conclusion is in accord with the established experimental results of ionic liquids.
Highlights
Deviations from the Nernst−Einstein relation are commonly attributed to ion−ion correlation and ion pairing
This observation suggests that the deviation from the Nernst− Einstein relation, i.e., (ΛN−E − ΛG−K) is inversely proportional to the viscosity η resembling the classical Walden rule, with Lmin being a system-specific parameter. We verified this relation with published experimental data for a variety of ionic liquids (ILs). These results indicate that viscosity is a dominating factor for the deviation from the Nernst−Einstein relation and provide a new avenue to gauge the extent of ion−ion correlations in electrolyte systems
It is found that σN−E is strongly system-size dependent as expected, while σG−K does not depend on the system size
Summary
“Physical chemistry of ionically conducting solutions” is one of the cornerstones for energy storage applications in supercapacitors and lithium-ion batteries.[1]. It is known that the self-diffusion coefficients have strong systemsize dependence (eq 9), and one would expect that the Nernst−Einstein ionic conductivity has the same tendency For the infinite dilute solution, this means the correlation length will diverge and Lmin → ∞
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
