A physical organogel electrolyte: Characterized by in situ thermo-irreversible gelation and single-ion-predominent conduction

Electrolytes are characterized by their ionic conductivity (??i). It is desirable that overall ??i results from the dominant contribution of the ions of interest (e.g. Li+ in lithium ion batteries or LIB). However, high values of cationic transference number (t+) achieved by solid or gel electrolytes have resulted in low ??i leading to inferior cell performances. Here we present an organogel polymer electrolyte characterized by a high liquid-electrolyte- level ??i (???101 mS cm-1) with high t+ of Li+ (>0.8) for LIB. A conventional liquid electrolyte in presence of a cyano resin was physically and irreversibly gelated at 60 ??C without any initiators and crosslinkers, showing the behavior of lower critical solution temperature. During gelation, ??i of the electrolyte followed a typical Arrhenius-type temperature dependency, even if its viscosity increased dramatically with temperature. Based on the Li + -driven ion conduction, LIB using the organogel electrolyte delivered significantly enhanced cyclability and thermal stability.open5

Raman Study of Ion-Molecules Interaction in Poly(Methylmetacrylate)-Based Gel Electrolytes

Gel electrolytes have been obtained, containing LiX (X = ClO(4), N(CF(3)SO)(2), AsF(6)) dissolved in a ethylene carbonate-propylene carbonate mixture and PMMA as polymeric matrix. Ionic conductivity has been measured, for two different lithium salts. The changes in the Raman spectra have been studied as a function of the polymer content, lithium salt concentrations and for different anions. Two satellite bands of the internal bending and stretching modes of ethylene carbonate appear in the spectrum of lithium containing samples, because of the cation-solvent molecule interaction

Study of ion-molecule interaction in poly(metylmethacrylate) based gel electrolytes by Raman-spectroscopy

Gel electrolytes based on polymethymetacrylate (PMMA) have been obtained using propylene carbonate and ethylene carbonate as gelating agents. They have a good mechanical stability, solvent retention and high electrical conductivity at room temperature (about 10(-3) Sem(-1)). In the aim of understanding the possible interactions of the mobile ions with polymer or solvent molecules, a comparative Raman study has been carried out on samples containing all the components of the gel electrolytes or some of them. The interaction with Li+ ions induces appreciable modifications of the vibrational spectra of the solvent molecules; two new bands appear at 900 cm(-1) and 730 cm(-1), slightly upshifted with respect to the stretching and bending modes of the ethylene carbonate ring. The change in size and polarizability of the anion species does not affect such cation-solvent interaction