Cation and anion diffusion coefficients in a solid polymer electrolyte measured by pulsed-field-gradient nuclear magnetic resonance

Abstract

AbslmcL Diffusion of lit-based and PFZ-based species in an amorphous p o w e x eleclmlyle has teen explored by pulsed-Beld-gradient (PFG) nuclear magnetic m n a n c e . n e erperiments were undertakn over a range of salt mncentrations and temperature enending 10 lower values of both wriables than in prwious studies Features of the lesults include a demonstration of different mechanisms lor anion and cation lranspon at high concentration, as shown bj their different temperature dependences, a reduced sensitivity of cation diffusion to salt concentration and a failure of the Nemst-Einstein relationship Cation hopping terween ionic dusters and the diffusion of neutral ion pairs are advanced as micmsmpic mechanisms lo aplain the data.

Lithium-Conducting Polymer Electrolytes for Chemical Power Sources

“…Arumugam et al [39] determined the diffusion coefficients of Li + and PF 6 ! in the amorphous electrolyte PEO3LiPF 6 by 7 Li and 31 P NMR spectroscopy with pulse field gradient in a wide temperature range (253 100oC) at a salt concentration of up to 0.25 mol dm !3 .…”

On the Reliability of Sodium Co-Intercalation in Expanded Graphite Prepared by Different Methods as Anodes for Sodium-Ion Batteries

“…18,19 Also, it is suggested that the anion plays a role in the transport of cations, either through correlated motion of cations and anions or via transport of cation-anion clusters. 10,20,21 Regarding the carbon material, the influence of several factors such as heteroelement contents, 8,22 structural differences in soft and hard carbons, 8,[23][24][25] morphological properties (nanowires, nanotubes, microbeads reduced graphene oxides or hollow carbon nanoparticles), [26][27][28][29][30][31][32] have been investigated as anodes for SIBs using standard electrolytes. Nonetheless, it is needed a further progress in the preparation of C-based materials.…”

Single Alkaline‐Ion (Li+, Na+) Conductors by Ion Exchange of Proton‐Conducting Ionomers and Polyelectrolytes

“…[2] The solvating properties of such environments are poor compared to what is known for aqueous systems: there is still significant residual ionic interaction leading to correlations of the motion of cations and anions [3,4] and even the formation of contact ion pairs and triple ions. [5,6] Such effects are most pronounced for polymeric solvents.…”

“…As a consequence, such materials are more efficient anions than alkaline ion conductors. [3,4] Of course, such differences are smeared out in liquid electrolytes, but even for these there is strong indication for the formation of contact ion pairs [7] and effective alkaline ion transference numbers smaller than the ones of anions (it is worth noting that alkaline ions can also be transferred by the counter diffusion of, for example, contact ion pairs and anions [8] ). The combination of relatively low total conductivity and low alkaline ion transference number is expected to lead to significant concentration polarization effects (formation of salt concentration gradients) even at moderate alkaline ion currents.…”