EXAFS and thermal studies on zinc polymeric electrolytes

The applications of X-ray absorption spectroscopy in the study of solid state ionics

“…Again the analysis was aided by computer simulation work [26] and has been supported by more recent, very detailed EXAFS experiments [2711 Similarly, the transition metal dopants in LiNbO3, photorefractive materials, were shown by EXAFS to predominantly to substitute on the Li site rather than the Nb site, ending a long running controversy [28][29][30]. Examples can also be drawn from amorphous materials and ionic glasses, with particularly useful studies of the local structure in the solid polymer electrolytes based on salt-containing polyethylene oxide [31,32].…”

Differential Anomalous X-ray Scattering from an Amorphous Polymer Electrolyte: [PPO]xZnBr2

“…The imaginary anomalous correction term, f', was calculated from the experimentally measured absorption coefficient, µ( ), using the atom-specific version of eq 7: rm = EqM 4 jtNreCQjh?1 (15) where i is Zn or Br. To obtain µ from the measured, total absorption coefficient, /¿tot, the experimental curve was scaled to the edge jump calculated from the standard absorption tables.…”

Heteroleptic Coordination Polymer Electrolytes Initiated by Lewis-Acidic Eutectics for Solid Zinc–Metal Batteries

“…A robust understanding of design criteria for SPEs with appreciable Zn 2+ -cation mobility has remained elusive since the multivalent nature of Zn 2+ carries a high charge capacity but induces enormous difficulties for its transport in solid-state media. − The foremost challenge of Zn 2+ -conducting SPEs consists in separating Zn 2+ from the tightly bound anions, considering the fact that the high ionic potential of Zn 2+ (Figure a) invariably leads to an insufficient ion dissociation, particularly in salt-concentrated regimes . Even using low-donicity anions like I – or TFSI – ((trifluoromethylsulfonyl)­imide), there remain ionic and/or neutral aggregates that set limitations on the formation of percolating ion channels, let alone other situations with strong Lewis-basic anions. , Hence, curing this issue calls for a polymer matrix with significant cation-solvating capability. , Nevertheless, Zn 2+ tends to coordinatively cross-link the polar macromolecular ligands in turn, resulting in shackle-like intrachain chelation or interchain networks (Figure b, top). Both the ligand exchange and polymeric segmental mobility are curtailed by such structurally inert entanglements.…”

“…Alternatively, converting Lewis-base polymer hosts to ones bearing Lewis-acid functionalities (e.g., boron-based groups) can release cations by preferentially binding anions, but the viability of synthesizing such polymers has yet to be established due to their instability . Indeed, Zn 2+ amplifies the conflict between cation dissociation and migration; most of the efforts on Zn 2+ SPEs have hitherto suffered from a ceiling conductivity level of 10 –6 –10 –8 S cm –1 and limited cationic contributions to the total transferred charge (below 0.20). , Despite recent advances in polymer gels, their scope is limited by solvent consumption and interfacial instability, and the mobile-phase components that cannot be ignored often cloud the ion-conduction events.…”