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Solid Electrolytes (SOE) with high ionic conductivity highly desirable in order to improve the efficiency of SOFCs at lower functioning temperature range) (350–500 °C). Triple perovskite Ba3SrNb2O9 based proton ion conductor have up-and-coming to enhance ionic conductivity at Low temperature range (LT) (350–500 °C). With this motivation we have successfully synthesized Ba3SrNb2O9 (BSNO) by solgel combustion method. Powder X-ray diffraction (XRD) confirms the formation of Triclinic crystal structure having space group P1, having lattice dimensions (a = 5.89340 Å, b = 5.88760 Å, c = 7.27360 Å). Rietveld Refinement of XRD data was carried out to get detail structural information by Full-Prof suite software. Electrical performance of the BSNO system were systematically studied by Electrochemical Impedance spectroscopy at functioning temperature 350–500 °C with interval of 50 °C. BSNO system exhibit conductivity of the order of 5.8 × 10−3 Scm−1 at 500 °C with the activation energy of the range of 0.48 eV. Charge Relaxations phenomenon very systematically explored by impedance loss spectra and it is very correlate with Modulus (M") as a function of frequency at several temperatures which used to clarify the charge relaxation dynamics in proton ion conducting BSNO material. [ABSTRACT FROM AUTHOR]

The formulation of a hybrid gel polymer electrolyte (HGPE) system comprising of polymethyl methacrylate (PMMA) and polylactic acid (PLA) as a hybrid host polymer doped with lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) has been successfully prepared in this study with the introduction of an ionic liquid, namely 1-Ethyl-3-methylimidazolium chloride (EMIMCl). Fourier transform infrared (FTIR) spectroscopy and X-ray diffraction (XRD) were used to investigate the structural features of HGPEs. The FTIR analysis revealed that the complexation changes the peak intensity at region C = O stretching, CH2 bending, and C-O stretching. Meanwhile, XRD showed that the addition of EMIMCl altered the HGPE properties and formed an amorphous structure. The prepared HGPE sample was examined for ionic conduction properties through electrical impedance spectroscopy (EIS). It shows that by adding an EMIMCl to the PMMA-PLA-LiTFSI HGPE has decreased the activation energy (Ea) and increased the ionic conductivity. The sample containing 15 wt.% has the lowest Ea value of 0.057 eV and the highest ionic conductivity at room temperature of 3.20 10−3 S cm−1. The itemperature dependence was studied in the temperature range from 303 K to 393 K, the HGPE systems were found to follow Arrhenius behavior. The effect of EMIMCl content had decreased the viscosity of HGPEs which led to the gel-like type behavior. The potential windows stability analysis revealed that the highest conducting sample was electrochemically stable up to 3.3 V versus Li/Li+, thus showing that the present electrolytes are promising to be applied as in Li-ions battery. [ABSTRACT FROM AUTHOR]

The aim of this study is to prepare Er and Sm co-doped CeO2 electrolytes via the Pechini method and investigate the effects of simultaneous addition of Sm and Er on the structural and electrical features of CeO2. The structural, functional group analysis, microstructures, and electrical properties of the electrolyte samples are conducted by X–ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy, and impedance spectroscopy (IS). All the calcined and sintered electrolytes were obtained with cubic fluorite crystal structure without secondary oxide phases. After sintering at 1400 °C, highly dense electrolytes were achieved (> 90%). The IS measurements indicated that the highest ionic conductivity was observed for the singly doped Ce0.80Sm0.20O1.90 (σ750 °C = 3.86 x 10−2 S/cm) electrolyte. σ750°C was found to be 3.82 x 10−2, 1.73 x 10−2, 0.61 x 10−2 S/cm for Ce0.80Er0.05Sm0.15O1.90, Ce0.80Er0.10Sm0.10O1.90 and Ce0.90Er0.10O1.95, respectively. [ABSTRACT FROM AUTHOR]

XRD measurements revealed that the investigated NaLiMnP2O7 compound consists of two phases: Na2Mn3(P2O7)2 and LiMnPO4. We found by XRD measurements that at 313 K Na2Mn3(P2O7)2 shows the triclinic symmetry of the compound (space group P-1), while LiMnPO4 phase showed the orthorhombic crystal symmetry (space group Pnma). The phase change between 773 K and 813 K was proved by thermal XRD, impedance spectroscopy and DTA analysis. No evident changes of peak intensities in thermal XRD were observed for LiMnPO4 phase. The impedance of NaLiMnP2O7 ceramics was measured at different temperatures and the total ionic conductivity of the compound was found to be of 5.3 × 10−9 S/m at 400 K on heating stage and only slightly higher on cooling stage. However, the conductivity value at 800 K was much higher – about 1.45 S/m on both stages. The step-like phase transition resulted in the conductivity increase of about 3 orders of magnitude in a narrow range of temperature. The ionic transference number was found to be 0.91 at room temperature. The XRD spectra and conductivity analysis of synthesised two separate phases showed that the phase transition takes place only in Na2Mn3(P2O7)2 ceramics. [ABSTRACT FROM AUTHOR]

Solution combustion route was employed for synthesis of the parent, La2Mo2O9 and its derivatives with formula La2-xBixMo1.95V0.05O9-δ (0.200 ≤ x ≤ 0.075). Powder X-Ray diffraction, SEM, DSC and impedance spectroscopy techniques were used to characterize the synthesized compounds. The results of structural, thermal and temperature dependent conductivity confirm the room temperature stabilization of the cubic phase in all the doped compounds. All the doped compounds exhibit enhanced electrical conductivity with respect to the parent compound in intermediate temperature range where as compounds with x = 0.075 and x = 0.100 show higher electrical conductivity compared to the vanadium substituted compound, La2Mo1.95V0.05O9-δ, throughout the whole temperature range. In the cubic region of La2Mo2O9, conductivity is slightly enhanced compared to the parent compound for the composition x = 0.100. However, it is lower in the case of single vanadium doped compound [1]. The highest conductivity is obtained for the composition x = 0.100 at temperature 750°C and the value is 0.041 S.cm−1. [ABSTRACT FROM AUTHOR]

In this work, the formulation of biopolymer electrolytes (BEs) system has been accomplished by incorporating various plasticizers with carboxymethyl cellulose–NH4Br through solution casting technique. The ionic conductivity at room temperature of BEs system was achieved at ∼10−4S cm−1with addition of 25 wt% NH4Br and enhanced to ∼10−3S cm−1when plasticizers were added. The temperature-dependence of the BEs system exhibits Arrhenius behavior. Jonschers power law was used to study the electrical properties and shows that the highest conducting BEs system can be represented by overlapping overlapping a large polaron tunneling model for poly(ethylene glycol) system a, small polaron hopping model for glycerol system, and a quantum mechanical tunneling model for ethylene carbonate system. [ABSTRACT FROM AUTHOR]

LaF3/SrF2multilayer heterostructures with thicknesses of individual layers in the range 5–100 nm have been grown on MgO(100) substrates using molecular beam epitaxy. The longitudinal conductivity of the films has been measured using impedance spectroscopy in the frequency range 10−1–106 Hz and a temperature range 300–570 K. The ionic DC conductivities have been determined from Nyquist impedance diagrams and activation energies from the Arrhenius–Frenkel equation. An increase of the DC conductivity has been observed to accompany decreased layer thickness for various thicknesses as small as 25 nm. The greatest conductivity has been shown for a multilayer heterostructure having thicknesses of 25 nm per layer. The structure has a conductivity two orders of magnitude greater than pure LaF3bulk material. The increasing conductivity can be understood as a redistribution of charge carriers through the interface due to differing chemical potentials of the materials, by strong lattice-constant mismatch, and/or by formation of a solid La1-xSrxF3-xsolution at the interface during the growth process. [ABSTRACT FROM PUBLISHER]

A solid polymer electrolyte based on lithium hydroxide (LiOH) added with polyethylene glycol and polyvinyl alcohol polymers was synthesized by solution casting. The structural variation with respect to loading wt% of LiOH reveals the semicrystalline property of polymer electrolyte. The differential scanning calorimetry data shows the onset of crystalline to amorphous transition, which occurs nearly to the melting peak, for higher salt content. The structural properties and cross-linking between polymer and salt were demonstrated by polarized optical microscopy. The polymer electrolytes were subjected to AC impedance analysis spectra for obtaining the ionic conductivity at different temperature. The charge carriers relax much faster for higher lithium salt concentration based polymer electrolyte and produces higher conductivity. The highest room temperature conductivity 2.63 × 10−5S/cm is obtained for 8 wt% loading of lithium salt based polymer electrolyte, confirming their use in preparation of ion conducting devices. [ABSTRACT FROM AUTHOR]

Graphene oxide was synthesized using modified Hummers method. The preparation of polyvinylchloride/graphene oxide nanocomposites was carried out using colloidal processing. The morphology of polyvinylchloride/graphene oxide nanocomposite confirms that graphene oxide was uniformly distributed within the polyvinylchloride matrix indicating complete exfoliation of graphene oxide. Significant improvement in the microhardness of the nanocomposite was observed as compared to neat polyvinylchloride. The impedance spectroscopy of nanocomposites was carried out in the frequency range (50 Hz to 35 MHz) and temperature range (80–150°C). Thus, based on the results obtained, we found that polyvinylchloride/graphene oxide nanocomposites hold great promise in many potential applications such as an electrode material for supercapacitors. [ABSTRACT FROM PUBLISHER]

Results of broadband dielectric/electric investigations of (Na0.5Pb0.5)(Mn0.5Nb0.5)O3ceramics are presented in wide frequency range 20 Hz–3 GHz. The electric properties of (Na0.5Pb0.5)(Mn0.5Nb0.5)O3ceramics are mainly governed by high ionic conductivity. One ionic and three polaronic contributions to electrical conductivity were successfully separated by employing impedance formalism. [ABSTRACT FROM PUBLISHER]

Results of broadband dielectric/electric investigations of (Na0.5Pb0.5)(Mn0.5Nb0.5)O3ceramics are presented in wide frequency range 20 Hz–3 GHz. The electric properties of (Na0.5Pb0.5)(Mn0.5Nb0.5)O3ceramics are mainly governed by high ionic conductivity. One ionic and three polaronic contributions to electrical conductivity were successfully separated by employing impedance formalism. [ABSTRACT FROM PUBLISHER]

Ceramics of lithium niobate with different lithium-to-niobium ratios were studied by impedance spectroscopy in the 1 Hz to 13 MHz frequency range and the 300–1000 °C temperature range. The static conductivity was determined for all compositions from Cole-Cole diagrams, and the evolution versus temperature was studied as a function of the Li/Nb ratios. The evolution of the ionic conductivity as a function of the temperature showed a change of slope at a temperature threshold. This change of slope may have been related to a modification of the conduction mechanism. At first, the mechanism followed a polaronic conduction model before the temperature threshold with an average activation energy of 0.84 eV; then it followed an ionic model after the temperature threshold, with an average activation energy of 1.20 eV. [ABSTRACT FROM PUBLISHER]

In this work, polymer electrolytes composed of PAN/PMMA/LiClO4with different plasticizers are prepared using solvent casting technique. Ionic conductivity of the electrolytes is evaluated with the help of ac impedance study at various temperatures. Structural and the complexation of the prepared electrolytes are studied by XRD and FTIR analysis, respectively. Thermogravimetric/differential thermal analysis (TG/DTA) is used to find the thermal stability of the polymer electrolytes. PAN/PMMA/EC/LiClO4-based plasticized polymer electrolyte is found to possess optimal properties in terms of conductivity and thermal stability. Porous nature of the polymer gel electrolytes is also confirmed by SEM analysis. [ABSTRACT FROM PUBLISHER]

Carboxyl methylcellulose (CMC) solid polymer electrolytes were prepared by utilizing oleic acid (OA) and different wt.% of propylene carbonate (PC) by using the solution casting technique. An ionic conductivity study of the films was done by using impedance spectroscopy. The highest ionic conductivity gained is 2.52 × 10−7 S cm−1at ambient temperature for sample CMC-OA-PC 10 wt.%. From transference number measurement (TNM), the value of cation diffusion coefficient, D+, and ionic mobility, μ+, was higher than the value of anion diffusion coefficient, D−, and ionic mobility, μ−. Thus, the results prove that the present samples were proton conductors. [ABSTRACT FROM PUBLISHER]

Ca properties in the sintering behavior of gadolinia-doped ceria were investigated. Their structures and conductivities were characterized by X-ray diffraction, scanning electron microscopy, and AC impedance spectroscopy. All the electrolytes were found to be of single phase with a cubic fluorite structure. AC impedance measurements showed that the conductivities for Ce0.85Gd0.10Ca0.05O2-δsample increased by increasing the sintering temperature. At 1500°C the Ce0.85Gd0.10Ca0.05O2-δhad low resistivity values, high conductivity, and low activation energy. [ABSTRACT FROM AUTHOR]

Ionic conducting membranes of gelatin plasticized with glycerol and containing LiI/I2 have been obtained and characterized by X-ray diffraction measurements, UV-Vis-NIR spectroscopy, thermal analysis and impedance spectroscopy. The transparent (80–90% in the visible range) membranes showed ionic conductivity value of 5 × 10−5 S/cm at room temperature, which increased to 3 × 10−3 S/cm at 80°C. All the ionic conductivity measurements as a function of temperature showed VTF dependence and activation energy of 8 kJ/mol. These samples also showed low glass transition temperature of −76°C. Moreover the samples were predominantly amorphous. The membranes applied to small electrochromic devices showed 20% of color change from colored to bleached states during more than 70 cronoamperometric cycles. [ABSTRACT FROM PUBLISHER]

Samples of Sn4+-substituted bismuth vanadate, formulated as Bi4SnxV2-xO11-(x/2)-δ in the composition range 0.07 ≤ x ≤ 0.30, were prepared by standard solid-state reactions. Sample characterization and the principal phase transitions (α ↔ β, β ↔ γ and γ' ↔ γ) were investigated by FT-IR spectroscopy, X-ray powder diffraction, differential thermal analysis (DTA) and AC impedance spectroscopy. For composition x = 0.07, the α ↔ β and β ↔ γ phase transitions were observed at temperatures of 451 and 536°C, respectively. DTA thermograms and Arrhenius plots of conductivities revealed the γ' ↔ γ phase transition at 411 and 423°C for x = 0.20 and 0.30, respectively. AC impedance plots showed that conductivity is mainly due to the grain contribution, which is evident in the enhanced short-range diffusion of oxide ion vacancy in the grains with increasing temperature. The highest ionic conductivity (5.03 × 10-5 S cm-1 at 300°C) was observed for the x = 0.17 solid solution with less pronounced thermal hysteresis. [ABSTRACT FROM AUTHOR]

Samples of Bi4CaxV2-xO11-(3x/2)-δ in the composition range 0.07 ≤ x ≤ 0.30 were prepared by conventional solid state reactions. The stability of different phases as a function of composition was analysed by X-ray powder diffraction, FT-IR spectra, differential thermal analysis and AC impedance spectroscopy. For the compositions x ≤ 0.10, monoclinic α-phase structure is retained at room temperature. For x = 0.13, orthorhombic β-phase is observed, whereas for x ≥ 0.17, high O2-conducting tetragonal γ-phase is stabilised. However, the highest ionic conductivity σ300°C = 3.27 × 10-4 S cm-1 was observed for x = 0.17. This higher value of conductivity of the substituted compound as compared to the parent compound can be attributed to the increased oxygen ion vacancies generated as a result of cation doping. AC impedance spectroscopy reveals the fact that this ionic conductivity is mainly due to the grain contribution. [ABSTRACT FROM AUTHOR]

For the first time, a new member of the BIMEVOX family, namely BICEVOX, has been synthesized by the partial solid-state substitution of Ce(IV) for vanadium in parent Bi4V2O11 solid electrolyte. The electrical conductivity in Bi4CexV2-xO11-(x/2)-δ has been investigated in the compositional range 0 ≤ x ≤ 0.30, using FT-IR, X-ray powder diffraction, differential thermal analysis and ac impedance spectroscopy. Owing to the long-term stabilization of α- and β-polymorphs compared to other members of the BIMEVOX family, the BICEVOX system may be a prospective solid electrolyte for intermediate temperature solid oxide fuel cells due to the significantly increased conductivity at lower temperatures observed for the compositions x > 0.20. [ABSTRACT FROM AUTHOR]

Highly textured thin films with small grain boundary regions can be used as model systems to directly measure the bulk conductivity of oxygen ion conducting oxides. Ionic conducting thin films and epitaxial heterostructures are also widely used to probe the effect of strain on the oxygen ion migration in oxide materials. For the purpose of these investigations a good lattice matching between the film and the substrate is required to promote the ordered film growth. Moreover, the substrate should be a good electrical insulator at high temperature to allow a reliable electrical characterization of the deposited film. Here we report the fabrication of an epitaxial heterostructure made with a double buffer layer of BaZrO3 and SrTiO3 grown on MgO substrates that fulfills both requirements. Based on such template platform, highly ordered (001) epitaxially oriented thin films of 15% Sm-doped CeO2 and 8 mol% Y2O3 stabilized ZrO2 are grown. Bulk conductivities as well as activation energies are measured for both materials, confirming the success of the approach. The reported insulating template platform promises potential application also for the electrical characterization of other novel electrolyte materials that still need a thorough understanding of their ionic conductivity. [ABSTRACT FROM AUTHOR]