E. Zygadło-Monikowska

Effects of inhomogeneity on ionic conductivity and relaxations in PEO and PEO-salt complexes

Electrical properties of purified poly(ethylene oxide)-PEO and PEO with dissolved lithium salts, PEO10:LiCF3SO3 and PEO10:LiN(CF3SO2)2, were investigated by impedance spectroscopy. Changes of the impedance spectra during crystallization and melting were recorded. Semicrystalline polymer films exhibited frequency dependence of conductivity with two limiting values of conductivity at low and at high frequency. It was concomitant with dispersion of the electric permittivity exhibiting the low-frequency values of the order of 200. In the case of PEO with dissolved salt, when the film was quasi-amorphous, the electric permittivity also exhibited pronounced dispersion, which was probably due to the presence of crystalline PEO–salt complexes. The dielectric relaxation caused by rearrangement of dipoles in PEO chain was observed at low temperatures and high frequencies.

Polymer-in-Salt Electrolytes Based on Acrylonitrile/Butyl Acrylate Copolymers and Lithium Salts

Solid polymeric electrolytes for battery purposes in the form of composites of lithium salts [LiI, LiN(CF3SO2)2, LiClO4, LiAlCl4, LiCF3SO3, and LiBF4] and acrylic polymeric matrixes [poly(acrylonitrile-co-butyl acrylate), poly(methyl methacrylate), and poly(butyl acrylate)] have been obtained by film casting from acetonitrile. The ionic conductivity (σ) as a function of temperature was studied by the impedance spectroscopy method. These systems show the highest σ values, on the order of 10-4−10-7 S·cm-1, at high salt concentrations (above 50 wt %), characteristic of polymer-in-salt electrolytes. The ionic conductivity and mechanical properties of composites depend on the chemical structure of the polymer matrix, the anion, and the salt concentration. The glass transition temperature (Tg) was determined from DSC studies. The introduction of a salt causes, in a majority of the composites studied, a considerable decrease in the Tg values, indicating a strong plasticizing effect. DSC studies show a multiphase...

Proton conducting electrolytes based on poly(2-acrylamido-2-methyl-1-propanesulfonic acid)

The conducting properties of poly(2-acrylamido-2-methyl-1-propanesulfonic acid) solutions in protic and aprotic solvents have been studied. Aprotic solvents such as dimethylformamide, mixtures of dimethylformamide and propylene carbonate, dimethylacetamide, as well as protic solvents such as water, methanol, glycerol and oxyethylene glycols were used. Colorless solutions or flexible membranes with ambient conductivity in the range of 1–10−6 S cm−1 were obtained depending on the kind of solvent used and polymer concentration. The effect of parameters connected with the mobility and concentration of protons, such as electrolyte viscosity, type and composition of solvent as well as the share of the polymeric matrix on the conductivity of the electrolytes studied has been discussed on the basis of the results obtained.

Structure Investigations of Dichloroaluminum Benzoates: An Unprecedented Example of a Monomeric Aluminum Complex with a Chelating Carboxylate Ligand

Dichloroaluminum benzoate and its adducts with Lewis bases show a large structural variety from molecular complexes to ionic species as indicated by X-ray diffraction, spectroscopic studies, and quantum-chemical calculations.

Polymer electrolytes comprising organometallic compounds

Composite polymeric electrolytes based on PEO complexes and ethyl aluminum alkoxides have been studied. The addition of the aluminum compounds causes a considerable reduction in the PEO crystalline phase content and provides very good mechanical and thermal stability up to 140°C. The glass transition temperatures of blends are low, falling within the - 64 to - 29°C range. The ionic conductivity of such systems reaches the value of 10 -5 S cm -1 at ambient temperature and that of 10 -3 S cm -1 at 60-70°C, Impedance studies show that these systems form a passive layer with a lithium electrode, which protects this electrode from corrosion processes.

Polymer electrolytes based on PEO and aluminum carboxylates

Abstract Studies on the application of aluminum alkoxycarboxylates (containing oxyethylene substituents) as additives to solid and gel polymeric electrolytes obtained on the basis of poly(ethylene oxide) (PEO) and inorganic lithium salts have been carried out. The solid composites obtained have a homogeneous structure and show conductivity of the order of 10−5 S/cm at 60–80 °C. The aluminum carboxylates applied assure good mechanical properties both of solid as well as of gel electrolytes also at elevated temperature due to the formation of a physical net with the polymer chains. The active role in the conduction process of the carboxylates used and their effect on the mechanical properties have been discussed on the basis of differential scanning calorimetry (DSC) and conductivity studies.

Ambient and subambient temperature proton-conducting polymer gel electrolytes

Abstract Nonaqueous proton-conducting polymer gels have been synthesized and characterized by impedance spectroscopy and cyclic voltammetry. Special emphasis has been put to the subambient temperature characteristics of the samples studied with respect to their possible application in electrochromic devices. The gels studied exhibit ambient temperature conductivities exceeding 10 −3 S/cm, which remains higher than 10 −4 S/cm even at −50 °C. The electrochemical stability of the studied protonic gels depends mainly on the type of solvent used and is the highest for samples plasticized with propylene carbonate.

Polymeric electrolytes based on sulfur dioxide copolymers

Abstract The present paper deals with applications of copolymers containing polar SO 2 units in main chains as matrices for polymeric electrolytes. Some of them exhibit conductivities exceeding 10 −5 S cm −1 at ambient temperatures. Blending of these copolymers with high molecular weight poly (ethylene oxide) results in an improvement of conductivities as well as mechanical and temperature stability of the studied electrolytes.

Polymer gel electrolytes based on glycidyl methacrylate homopolymer and copolymers

Abstract Gel electrolytes have been prepared by two-step polymerization or copolymerization of glycidyl methacrylate (2,3-methoxypropyl methacrylate) in the presence of LiClO4 and propylene carbonate or other organic solvents. In the first step a free-radical initiator was used and then the linear polymers were crosslinked by means of SO2 or BF3. The conductivity of the electrolytes obtained was studied by means of impedance spectroscopy. It was found that several of the electrolytes exhibit ambient temperature conductivities exceeding 10−3 S/cm and retain conductivities as high as 10−5 S/cm up to -50°C. The temperature dependence of conductivity for several samples above room temperature can be analyzed according to the classical Arrhenius plot, whereas at subambient temperature they exhibit Vogel-Tammann-Fulcher-type behavior. The conductivity and activation energy values obtained indicate that charge transfer occurs mainly in the liquid phase. The conducting properties of the electrolytes studied stron...