Expanding the chemistry of single‐ion conducting poly(ionic liquid)s with polyhedral boron anions

The synthesis of a new family of single‐ion conducting random copolymers bearing polyhedral boron anions is reported. For this purpose two novel ionic monomers, namely [B₁₂H₁₁(OCH₂CH₂)₂OC(?O)C(CH₃)?CH₂]^2?[(C₄H₉)₄N⁺]₂ and [8‐(OCH₂CH₂)₂OC(?O)C(CH₃)?CH₂‐3,3′‐Co(1,2‐C₂B₉H₁₀)(1′,2′‐C₂B₉H₁₁)]^?K⁺, having methacrylate function, diethylene glycol bridge and closo‐dodecaborate or cobalt bis(1,2‐dicarbollide) anions were designed. Such monomers differ from previously reported ones by (i) chemically attached highly delocalized boron anions, by (ii) valency of the anion (divalent anion and monovalent one) and by (iii) the presence of oxyethylene flexible spacer between the methacrylate group and bonded anion. Their free radical copolymerization with poly(ethylene glycol) methyl ether methacrylate and subsequent ion exchange provided lithium‐ion conducting polyelectrolytes showing low glass transition temperature (?53 to ?49 °C), ionic conductivity up to 9.1 × 10^?7 S cm^?1, lithium transference number up to 0.61 (70 °C) and electrochemical stability up to 4.1 V versus Li⁺/Li (70 °C). The incorporation of propylene carbonate (20–40 wt%) into the copolymers resulted in the enhancement of their ionic conductivity by one order of magnitude and significantly increased their electrochemical stability up to 4.7 V versus Li⁺/Li (70 °C). © 2019 Society of Chemical Industry     

Review on zirconate-cerate-based electrolytes for proton-conducting solid oxide fuel cell

The performance of low-to-intermediate temperature (400–800?°C) solid oxide fuel cells (SOFCs) depends on the properties of electrolyte used. SOFC performance can be enhanced by replacing electrolyte materials from conventional oxide ion (O^2-) conductors with proton (H⁺) conductors because H⁺ conductors have higher ionic conductivity and theoretical electrical efficiency than O^2- conductors within the target temperature range. Electrolytes based on cerate and/or zirconate have been proposed as potential H⁺ conductors. Cerate-based electrolytes have the highest H⁺ conductivity, but they are chemically and thermally unstable during redox cycles, whereas zirconate-based electrolytes exhibit the opposite properties. Thus, tailoring the properties of cerate and/or zirconate electrolytes by doping with rare-earth metals has become a main concern for many researchers to further improve the ionic conductivity and stability of electrolytes. This article provides an overview on the properties of four types of cerate and/or zirconate electrolytes including cerate-based, zirconate-based, single-doped cerate–zirconate and hybrid-doped cerate–zirconate. The properties of the proton electrolytes such as ionic conductivity, chemical stability and sinterability are also systematically discussed. This review further provides a summary of the performance of SOFCs operated with cerate and/or zirconate proton conductors and the actual potential of these materials as alternative electrolytes for proton-conducting SOFC application.     

Ionic liquid electrolytes based on multi-methoxyethyl substituted ammoniums and perfluorinated sulfonimides: Preparation, characterization, and properties

New functionalized ionic liquids (ILs), comprised of multi-methoxyethyl substituted quaternary ammonium cations (i.e. [N(CH₂CH₂OCH₃)_4−n(R)_n]⁺; n = 1, R = CH₃OCH₂CH₂; n = 1, R = CH₃, CH₂CH₃; n = 2, R = CH₃CH₂), and two representative perfluorinated sulfonimide anions (i.e. bis(fluorosulfonyl)imide (FSI⁻) and bis(trifluoromethanesulfonyl)imide (TFSI⁻)), were prepared. Their fundamental properties, including phase transition, thermal stability, viscosity, density, specific conductivity and electrochemical window, were extensively characterized. These multi-ether functionalized ionic liquids exhibit good capability of dissolving lithium salts. Their binary electrolytes containing high concentration of the corresponding lithium salt ([Li⁺] >1.6 mol kg⁻¹) show Li⁺ ion transference number (tLi⁺) as high as 0.6-0.7. Their electrochemical stability allows Li deposition/stripping realized at room temperature. The desired properties of these multi-ether functionalized ionic liquids make them potential electrolytes for Li (or Li-ion) batteries.     

SYNTHETIC INORGANIC ION-EXCHANGE MATERIALS. XXXXI. ION EXCHANGE EQUILIBRIA OF ALKALI METAL IONS/HYDROGEN IONS ON TIN(IV) ANTIMONATE

Ion exchange equilibria of alkali metal ions (Li⁺, Na⁺, K⁺,, Rb⁺, and Cs⁺)H⁺, systems have been studied in MNO-j-HNOj media with ionic strength of 0.1 at 30, 45 and 60 °C on tin(IV) antimonate as a cation exchanger. The ion exchange isotherms have been measured for both forward and backward reactions by the batch technique. The isotherms showed S-shaped curves for all exchange systems studied. The selectivity coefficients (logarithmic scale) vary with the equivalent fraction X_M of alkali metal ions in the exchanger and give two linear functions of X_M with a break point (X_M= 0.14, except 0.04 for Li⁺, /H⁺) indicating two different exchanging sites. The selectivity sequence, Na⁺, ? K⁺, ? Rb⁺, ? Cs⁺, ? ? Li, holds in the range of Xu= (0 - 0.04) and the sequence, Cs < Rb ⁺, ? K ⁺, ? Na ⁺, < Li ⁺, applies when X_M is higher than 0.14.

Hypothetical thermodynamic data on “zero loading” of the ion exchange reaction was evaluated.     

Ionic Conductivity of Cross-linked Polymethacrylate Derivatives/Cyclophosphazenes/Li<Superscript>+</Superscript> Salt Complexes

The role of cyclophosphazenes with oxyethylene chains (N₃P₃(OCH₂CH₂)_nOCH₃, (n = 3, 3, n = 7.2, 4) and N₄P₄[OC₆H₄O(CH₂CH₂O)_7.2CH₃]₈ (8) for the synthesis and ionic conductivity in polymethacrylate networks was studied. Reflecting the structural features of cyclophosphazenes, the ⁷Li NMR spectra of the mixture of 3 and LiN(SO₂CF₃)₂ showed that more than 40% of the Li⁺ salt could exist as a free ion at room temperature. Similar values were obtained for 4 and 8. Cross-linked methacrylate polymers (12–14, and 16–18) were prepared from the reaction of poly(ethylene glycol) methyl ether methacrylate and poly(ethylene glycol) dimethacrylate both in the presence of these cyclophosphazenes which act as molecular imprinting molecules (method II, M-II) and without the cyclophosphazene (method I) DSC studies of the imprinted polymer, 12(20)/3/Li⁺ system after removal of the cyclophosphazene showed that the glass transition temperature range (ΔT_g) becomes significantly narrower compared to that of the unimprinted 11(20)/3/Li⁺ system, where cross-linked polymer 11(20) was prepared in the absence of the cyclophosphazenes (method I, M-I). The ionic conductivity of the Li⁺/cross-linked polymer system was improved by the subsequent readdition of the cyclophosphazenes. The 12(20)/3/Li⁺ complex showed a conductivity of 1.1 × 10⁻³ S/cm at 90 °C, which was two times higher than that of the 11(20)/3/Li⁺ complex. The effectiveness of the small molecule imprinting technique for the preparation of cross-linked polyelectrolytes with high conductivity and mechanical stability is discussed. We dedicate this paper to Professor Christopher W. Allen for his creative, pioneering work in inorganic ring and inorganic-organic hybrid polymers.     

Enhanced ion conductivity of poly(ethylene oxide)-based single ion conductors with lithium 1,2,3-triazolate end groups

Poly(ethylene oxide) (PEO)-based single ion conductors (SICs) are of great interest for applications in modern lithium ion batteries. They have several advantages over other common electrolytes such as high cation transference numbers, low toxicity, and nonflammability, but their major disadvantage is the low ion conductivity. Here, linear PEO-based SICs with lithium 1,2,3-triazolate (TrLi) end groups are synthesized and studied in terms of crystallinity by differential scanning calorimetry, and with respect to ion conductivity by impedance spectroscopy. Introduction of TrLi end groups to PEO chains reduces its crystallinity and melting temperature as well as an enhancement of the ion conductivity up to 8.0·10⁻⁶ S cm⁻¹ at 70°C is observed. The increased ion conductivity is a direct result of the Tr rings, which can actively contribute to the conduction mechanism. In comparison with conductivities of other PEO-based SICs reached so far (σ₀ ≤ 10⁻⁶ S cm⁻¹), the results of this study show that the introduction of TrLi end groups is a new approach to enhance the Li⁺-ion conductivity of PEO-based SICs that have also a good electrochemical stability versus lithium electrodes as revealed by linear sweep voltammetry. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 46949.     

Ion Exchange Kinetics of Heavy Metal Ions on Organic–Inorganic Composite Cation Exchanger Poly-o-toluidine Zr(IV) Tungstate

To study the ion exchange kinetics of heavy metal ions on the organic–inorganic composite cation exchanger poly-o-toluidine Zr(IV) tungstate, Nernst–Planck was computer simulated. Simulated numerical results for counter ions (Cu, Zn, Cd and Pb) of equal valence and four different ionic mobilities are presented to understand the ionic diffusion process. These results are based on the fractional attainment of equilibrium U(τ), of the counter ions under study. The forward (M²⁺–H⁺) and reverse (H⁺–M²⁺) ion exchange processes are justified as the particle diffusion phenomenon. The self-diffusion coefficient (D _o ), energy of activation (E _a ), and entropy of activation (?S*) have also been estimated to understand the ion exchange process occurring over the surface of this cation exchanger and indicated that the ion exchange process is feasible and spontaneous. It is concluded that the difference in activation energies and entropy of activation may facilitate the separation of metal ions. The regeneration capability of this cation exchanger was also explained.     

Synthesis and alkaline stability of novel cardo poly(aryl ether sulfone)s with pendent quaternary ammonium aliphatic side chains for anion exchange membranes

Novel cardo poly(aryl ether sulfone)s containing pendent -[CH₂CH₂NMe₃]⁺OH⁻, or -[CH₂CH₂CH₂NMe₃]⁺OH⁻ groups, and partially fluorinated cardo poly(aryl ether sulfone) containing pendent -[CH₂CH₂CH₂NMe₃]⁺OH⁻ groups were synthesized and examined with the focus of understanding how the polymer chemical structure affects their morphology, ion conductivity and alkaline stability. The resulting quaternized polymers exhibited outstanding solubility in polar aprotic solvents. The partially fluorinated cardo poly(aryl ether sulfone)s (PES-PF-OH) with ion-exchange capacity of 1.44 meq g⁻¹ displayed the highest ion conductivities, varied from 3.0 × 10⁻² to 4.1 × 10⁻² S cm⁻¹ over the range 20-60 °C. TEM revealed that PES-PF-OH membrane exhibited a distinct phase-separated morphology comprised of interconnected ionic clusters in size of 1-2 nm. The studies on alkaline stability of the membranes revealed that the PES-PF-OH polymer was not stable under strong basic conditions. The quarternized polymers containing pendent -[CH₂CH₂NMe₃]⁺OH⁻, or -[CH₂CH₂CH₂NMe₃]⁺OH⁻ groups mainly underwent Hofmann elimination and S_N2 substitution reaction.     

Development of thin‐film composite membranes for carbon dioxide and methane separation using sulfonated poly(phenylene oxide)

Novel membranes based on sulfonated poly (phenylene oxide) (SPPO) was developed. SPPO membranes in the hydrogen form were converted to metal ion forms. The effect of exchange with metal ions including monovalent (Li⁺, Na⁺, K⁺), divalent (Mg²⁺, Ba²⁺, Ca²⁺) and trivalent (Al³⁺) ions was investigated in terms of permeation rate and permeation rate ratios for CO₂ and CH₄ gases. Both dense homogeneous membranes and thin‐film composite (TFC) membranes were studied for their gas separation characteristics. The effect of membrane preparation conditions and operating parameters on the membrane performance were also investigated. The selectivity of the TFC membrane increased as the cationic charge density increased as a result of electrostatic cross‐linking. TFC membrane of very high selectivity was achieved by coating a thin layer of SPPO‐Mg on a PES substrate. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 76: 735–742, 2000     

Preparation and Characterization of Composite Microporous Gel Polymer Electrolytes Containing SiO2(Li+)

In this paper, the single ionic conductor SiO₂(Li⁺) was first synthesized from Tetraethylorthosilicate and γ-(2,3-epoxypropoxy) propyltrimethoxysilane (KH560) by sol–gel hydrolysis and then neutralized by lithium hydroxide in methanol. The poly(vinylidene fluoride) based composite microporous gel polymer electrolytes (CMGPEs) doped with SiO₂(Li⁺) was prepared by phase inversion method and the desirable CMGPEs was obtained after being activated in liquid electrolyte. The physicochemical properties of the CMGPEs were characterized by FT-IR, DSC, XRD, TG, stress–strain response and electrochemical measurements. It was found that with the addition of SiO₂(Li⁺), the degree of crystallization of microporous polymer membrane was decreased while its porosity increased, which could promote the absorption and gelation of liquid electrolyte. In addition, due to vast amount of Li⁺ ions in the SiO₂(Li⁺), it would promote ionic conductivity at room temperature for the CMGPEs. When the content of SiO₂(Li⁺) reached 5 %wt, the ionic conductivity of the CMGPEs could reach 10^?2S/cm order of magnitude at room temperature and the reciprocal temperature dependence of ionic conductivity of as-prepared CMGPEs follow arrhenius equation, in addition, its electrochemical stability window could reach 5.2 V.     

Modeling of aqueous electrolyte solutions based on perturbed-chain statistical associating fluid theory incorporated with primitive mean spherical approximation

In this work an equation of state applicable to the system containing electrolytes has been developed by coupling the perturbed chain statistical associating fluid theory (PC-SAFT) with the primitive mean spherical approximation. The resulting electrolyte equation of state is characterized by 4 ion parameters for each of the cation and anion contained in aqueous solutions, and 4 ion specific parameters for each of six cations (Li⁺, Na⁺, K⁺, Rb⁺, Mg²⁺ and Ca²⁺) and six anions (Cl⁻, Br⁻, I⁻, HCO₃⁻, NO₃⁻ and SO₄²⁻) were estimated, based upon the individual ion approach, from the fitting of experimental densities and mean ionic activity coefficients of 26 aqueous single-salt solutions at 298.15 K and 1 bar. The present equation of state with the estimated individual ion parameters has been found to satisfactorily describe not only the densities and mean ionic activity coefficients, but also osmotic coefficients and water activities of single-salt aqueous solutions. Furthermore, the present model was extended to two-salt aqueous solutions, and it has been found that thermodynamic properties such as mentioned above, of two-salt solutions, can be well predicted with the present model, without any additional adjustable parameters.     

Composition effects on ion transport in a polyelectrolyte gel with the addition of ion dissociators

The polymerization of lithium 2-acrylamido-2-methyl-1-propane sulphonic acid with N,N′-dimethylacrylamide has yielded polyelectrolyte gels which have the favourable property of being single ion conductors. The use of single ion conductors ensures that the transport number of lithium is close to unity. The mobility of the lithium ion is still quite low in these systems, resulting in low ionic conductivity. To increase ionic conductivity more charge carriers can be added however competing effects arise between increasing the number of charge carriers and decreasing the mobility of these charge carriers. In this paper the monomer ratio of the copolymer polyelectrolyte is varied to investigate the effect increasing the number of charge carriers has on the ionic conductivity and lithium ion and solvent diffusivity using pfg-NMR. Ion dissociators such as TiO₂ nano-particles and a zwitterionic compound based on 1-butylimidazolium-3-(N-butanesulfonate) have been added in an attempt to further increase the ionic conductivity of the system. It was found that the system with the highest ionic conductivity had the lowest solvent mobility in the presence of zwitterion. Without zwitterion the mobility of the solvent appears to determine the maximum ionic conductivity achievable.     

Counterion effects on the aqueous solution viscosity of cationic surfactants

The effect of varying counterion structure on the aqueous solution viscosity of various cationic surfactants was systematically examined for compounds of the type: CH₃(CH₂) _x N(CH₃)₃YAr. Ar = functionally substituted aryl moieties and Y = carboxylate (CO₂ ⁻), sulfinate (SO₂ ⁻) or sulfonate (SO₃ ⁻). Aqueous solution viscosity, which is assumed to be a measure of ion pair stability, is clearly affected by anion and cation structure, temperature, concentration and stoichiometry. An ortho substituent to the anionic functionality, e.g. hydroxyl, substantially increases ion pair stabilization. Ion pair stability is also enhanced by increasing the solution concentration, decreasing temperature, increasing cation/anion ratio or by increasing the alkyl (x) chain length.     

Ion transport studies in PEO:NH4ClO4 polymer electrolyte and its composite with Al2O3

Composition, temperature and humidity dependence of ionic conductivity in polyethylene oxide (PEO):NH₄ClO₄ polymer electrolyte composite obtained by the dispersal of Al₂O₃ is reported. The dispersal of Al₂O₃ introduces significant changes in the conductivity vs. composition isotherm. The conductivity of the composite peaks at two concentrations of Al₂O₃ is ~2 × 10^?5 S cm^?1. For studying ion dynamics, motional narrowing of ¹H NMR line with temperature is also reported. In PEO:NH₄ClO₄ (without dispersed Al₂O₃), two ¹H frequency-shifted NMR lines are seen (one of these have been assigned to the ¹H belonging to –CH₂–CH₂– chain of the polymer and the other to NH₄ ⁺ complexed with the chain). For the (PEO:NH₄ClO₄) + Al₂O₃ composites, however, one additional narrow peak is also seen at temperatures higher than 40 °C. This has been interpreted in terms of some hopping H⁺ ions getting loosely bonded to Al₂O₃, forming Al(OH)₃, which possibly releases an additional mobile protonic species (OH^?).     

A-site acceptor-doping strategy to enhance oxygen transport in sodium–bismuth–titanate perovskite

Sodium–bismuth–titanate (NBT) has recently been shown to contain high levels of oxide ion conductivity. Here we report the effect of A-site monovalent ions, M⁺ = K⁺ and Li⁺, on the electrical conductivity of NBT. The partial replacement of Bi³⁺ with monovalent ions improved the ionic conductivity by over one order of magnitude without an apparent change of the conduction mechanism, which is attributed to an increase in the oxygen vacancy concentration based on an acceptor-doping approach. The ¹⁸O tracer-diffusion coefficient (D*) determined by the isotope exchange depth profile method in combination with secondary ion mass spectrometry confirmed that oxygen ions are the main charge carriers in the system. Among these acceptor-doped samples, 4% Li doping provides the highest total conductivity, leading to a further discussion of doping strategies for NBT-based materials to enhance the electrical behavior, is discussed. Comparisons with other oxide-ion conductors and an oxygen-vacancy diffusivity limit model in perovskite lattice suggested that the doped NBT-based materials might already have achieved the optimization of the ionic conductivity.     

Cation and anion sizes influence in the temperature dependence of the electrical conductivity in nine imidazolium based ionic liquids

In this paper we present experimental data on the temperature dependence of the electrical conductivity, σ, in nine different imidazolium based ionic liquids. We have measured four 1-(alkyl chain)-3-methyl imidazolium tetrafluoroborate (C_nMIM-BF₄) ionic liquids, with C_n representing ethyl, butyl, hexyl and octyl chains, to study the dependence of σ with the cation length. Moreover, to study the influence of the anion size in the electrical conductivity, we measured six different EMIM-X, with X being, from smaller to bigger sizes, Cl⁻, Br⁻, BF₄⁻, PF₆⁻, ethyl sulfate and tosylate. The measurements were performed at atmospheric pressure, and the studied temperature range covers the liquid phase of the analyzed compounds. We have fitted the electrical conductivity data of the nine ionic liquids using a Vogel-Tamman-Fulcher (VTF) equation with high precision. We observe from the measured data that the electrical conductivity decreases its value as the alkyl chain of the cation increases. In contrast, we do not observe that dependence with the anion size, where there seems to be an optimal size (that of BF₄⁻) for which σ reaches its maximum value, being lower for smaller or bigger anion sizes. Finally, if we plot the natural logarithm of σ versus the distance in temperature to the glass transition one for each IL, we observe that the resulting straight lines are ordered with the anion (or cation) sizes for all nine compounds measured, i.e., lower σ values for bigger sizes.     

Simple introduction of anion trapping site to polymer electrolytes through dehydrocoupling or hydroboration reaction using 9-borabicyclo[3.3.1]nonane

Organoboron-based anion trapping polymer electrolytes were synthesized through hydroboration or dehydrocoupling reaction between poly(propylene oxide) (PPO) oligomer (M_n = 400, 1200, 2000 and 4000) and 9-borabicyclo[3.3.1]nonane (9-BBN). Obtained oligomers were added various lithium salts (LiN(CF₃SO₂)₂, LiSO₃CF₃, LiCO₂CF₃ or LiBr) to analyze the ionic conductivity and lithium ion transference number (tLi⁺). The ionic conductivity of the oligomer in the presence of LiN(CF₃SO₂)₂ showed higher ionic conductivity than other systems, however, the tLi⁺ was less than 0.3. When LiSO₃CF₃ or LiCO₂CF₃, was added high tLi⁺ over 0.6 was obtained. Such difference in tLi⁺ can be explained by HSAB principle. Since boron is a hard acid, soft (CF₃SO₂)₂N⁻ anion can not be trapped effectively. High ionic conductivity of 1.3 × 10⁻⁶ S cm⁻¹ and high tLi⁺ of 0.73 was obtained when PPO chain length was 2000. These values of facilely prepared polymer electrolytes are comparable to those of the PPOs having covalently bonded salt moieties on the chain ends.     

A redox poly(ionic liquid) hydrogel: Facile method of synthesis and electrochemical sensing

In this article, a redox-responsive poly(ionic liquid) (redox-PIL) hydrogel Poly(1-vinyl-3-propionate imidazole phenothiazine sulfonic acid)-chitosan [Poly(VPI⁺PTZ-(CH₂)₃SO₃⁻)-CS] was produced by using chitosan (CS) crosslinking with redox-PIL Poly(1-vinyl-3-propionate imidazole phenothiazine sulfonic acid [Poly(VPI⁺PTZ-(CH₂)₃SO₃⁻)]. The incorporation of redox-active counter anions 3-(phenothiazine-10-yl) propane 1-sulfonic acid anions (PTZ-(CH₂)₃SO₃⁻) into cationic PIL-polyimidazole rendered Poly(VPI⁺PTZ-(CH₂)₃SO₃⁻) with electron catalytic ability, ionic conductivity, and electron conductivity. Poly(VPI⁺PTZ-(CH₂)₃SO₃⁻)-CS combines the properties of hydrogel and redox-PIL, thus offering intrinsic porous conducting frameworks and promoting the transport of charges, ions, and molecules, leading hydrogel with excellent electrochemical properties. The crosslinking occurrence of Poly(VPI⁺PTZ-(CH₂)₃SO₃⁻) and CS resulting from the synthetic process of hydrogel was verified by differential scanning calorimetry and thermogravimetric analysis. A three-dimensional polymer network hydrogel with good biocompatibility and permeability was formed after crosslinking. In addition, only 64% weight loss within 600 °C was observed in Poly(VPI⁺PTZ-(CH₂)₃SO₃⁻)-CS representing its thermally stable performance. When used as an electrochemical sensor, the hydrogel-modified gold electrode improved the electrocatalytic oxidation of cysteine. Differential pulse voltammetry results indicated that the detection range was from 5 × 10⁻⁸ to 5 × 10⁻³ M and the limit of detection was 6.64 × 10⁻⁸ M. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 48051.     

Ionic liquids and plastic crystals based on tertiary sulfonium and bis(fluorosulfonyl)imide

A new series of low-melting, low-viscosity, hydrophobic ionic liquids based on relatively small tertiary sulfonium cations ([R¹R²R³S]⁺, wherein R¹, R², R³ = CH₃ or C₂H₅, R³ = CH₂CH₂OCH₃, CH₂CH₂COOCH₃, CH₂CH₂CN) and bis(fluorosulfonyl)imide (FSI⁻) anion have been prepared and characterized. The important physicochemical and electrochemical properties of these salts, such as melting point, glass transition, viscosity, density, ionic conductivity, thermal and electrochemical stability, have been determined. The influence of structure variation in the tertiary sulfonium cations on the above physicochemical properties is discussed. Among these new salts, some of them show the desirable properties including low-melting points, low viscosities, and high conductivities, to be selected as potential candidates as electrolytes in energy devices, and two salts are ionic plastic crystals.     

A novel polymer electrolyte based on polydioxolane polyurethane with Na+ single‐ionic conductivity

A series of novel polyurethane ionomers with polydioxolane (PDXL) as soft segment was prepared and characterized by Fourier transform infrared spectroscopy, differential scanning calorimetry, and dynamic mechanical analysis. The ionomers obtained were Na⁺ single‐ionic conductors. Their ionic conductivity and water absorption were tested. At medium temperature (> 75°C), the conductivity of ∼ 10⁻⁵ s cm⁻¹ was reached. The temperature dependence of conductivity could not be well expressed by both Arrhenius and VTF equations. When ionization level was fixed, the conductivity increased as the Mn of PDXL decreased. We also discussed the effect of ionization level on water absorption. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 71: 1711–1719, 1999