A single cation or anion dendrimer-based liquid electrolyte

Abstract

The proposed dendrimer based liquid electrolyte is a single-ion conductor where ion transport is altered by the nature of the chemical functionalities leading to large variations in anion diffusion and hence ionic transference number.

Time–Temperature Scaling and Dielectric Modeling of Conductivity Spectra of Single-Ion Conducting Liquid Dendrimer Electrolytes

“…Absence of infinite chains similar to polymers should necessarily eliminate this possibility. Additionally, Arrhenius behavior of temperature dependency of conductivity and self-diffusion coefficients of Li + and PF 6 – ions (Figures b and S1, respectively) further supports this proposition . The more convenient explanation would be that the improvement in ionic conductivity is influenced by the increase in the number density of free charge carriers with temperature in G 1 -CN-LiPF 6 .…”

“…On the other hand, the nonzero transference number value ( t –/+ = 0.1–0.2) of the minority charge carriers suggests that the PETIM-dendrimer electrolytes also retain the characteristics of conventional liquid electrolytes. The interesting switch in the nature of predominant charge carriers in dendrimer electrolytes suggests a unique ion transport property, which was previously investigated in detail via the combination of various spectroscopic and electrochemical techniques in ref . As mentioned earlier, the significant difference in t + between the two dendrimers is correlated to the differences in values of the D PF 6 – or anion mobility.…”

“…The extent of salt dissociation in both the G 1 -CN-LiPF 6 and G 1 -COOR-LiPF 6 dendrimers is investigated via FTIR spectroscopy, as shown in Figure S2. In the IR spectra of G 1 -CN-LiPF 6 , an additional band at 875 cm –1 appears in addition to the free PF 6 – anion band at 848 cm –1 . This suggests the presence of the tridentate ligand pair of LiPF 6 salt in G 1 -CN-LiPF 6 .…”

“…To the best of our knowledge, reports of unity transference number in liquids especially in viscous liquids are rare. Previously, few reports demonstrated the potential of branched dendrimers as alternative lithium conducting electrolytes. − We have recently reported first generation poly­(propyl ether imine) (G 1 -PETIM) dendrimer electrolytes which exhibit a lithium transference number near unity ( t Li + = 1) even in the liquid state. The type of predominant charge carrier, i.e., cation or anion, could be precisely tuned via a suitable choice of the peripheral chemical functionality ( t Li + = 0.9 for G 1 -ester; t PF 6 – = 0.8 for G 1 -cyano), keeping constant the linker and branching moieties.…”

Novel Chemical Cross-Linked Ionogel Based on Acrylate Terminated Hyperbranched Polymer with Superior Ionic Conductivity for High Performance Lithium-Ion Batteries

“…Highly branched polymers, as one of the fastest growing polymers in function macromolecular materials, have captured more and more attention because of their unique structural characteristics and properties such as low crystallinity, controlled flexibility, and various functionalities [27,28,29,30,31,32,33,34]. Hyperbranched polymers (HPs), a unique class of branched polymer with a large number of terminal groups, have been used as hot hosts for use in ion-conductive polymer electrolytes due to their completely amorphous and low glass transition temperatures [35,36,37,38,39].…”