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1.
Gel polymer electrolytes (GPE) obtained by immobilizing a solution of zinc triflate (ZnTr) in an ionic liquid, namely 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide [emim][Tf2N] within a biodegradable polymeric matrix of poly-ε-caprolactone (PCL) were prepared by a simple solvent cast technique for different concentrations of the ionic liquid. The electrolyte with the composition 75 wt% PCL: 25 wt% ZnTr+100 wt% [emim][Tf2N] showed the highest ionic conductivity of 1.1×10−4 S cm−1 at 25 °C and favored by the rich amorphous phase of the GPE as confirmed from room temperature X-ray diffraction analysis (XRD). The morphology of the GPE was examined using scanning electron microscopy (SEM) which revealed the homogeneity of the prepared GPE system. The temperature dependence of electrical conductivity of the GPE followed the Arrhenius behavior. The Zn2+ ionic transport number has been determined to be ~0.62 which denotes the predominant contribution of zinc ion towards total ionic conductivity. The electrochemical stability window of GPE is found to be 2.5 V with a thermal stability upto 200 °C. This eco-friendly and safe electrolyte may be used to fabricate compostable batteries, in future, with a suitable selection of other components of the battery system.  相似文献   

2.
A pyrochlore-related Ce2Zr2O8−x phase has been prepared in a reduction reoxidation process from Ce0.5Zr0.5O2 powders. Ce2Zr2O8−x, based on a cubic symmetry with a=1.053 nm, decomposes in nitrogen at 800 °C, but remains stable up to 900 °C in air. It shows mixed oxygen ionic and electronic conductivity. The bulk conductivity at 700 °C is 4×10−4 S cm−1 in air and 1×10−2 S cm−1 in nitrogen, and the activation energy is 1.27 eV in air. In nitrogen, the Arrhenius law is not obeyed, and a curved plot was obtained from 400 to 700 °C; then, the conductivity decreased rapidly due to the thermal decomposition of Ce2Zr2O8−x.  相似文献   

3.
Tripathi  Mukta  Tripathi  S.K. 《Ionics》2017,23(10):2735-2746

Ionic liquid-based gel polymer electrolyte (GPE) has been synthesized using standard solution cast technique. Different weight percent of ionic liquid, 1-Butyl-3-methylimidazolium chloride (BMIMCl) and liquid electrolyte, ethylene carbonate (EC)–propylene carbonate (PC)–tetra ethyl ammonium tetra fluoro borate (TEABF4) was incorporated in polymer, poly(vinylidene fluoride-co-hexafluoro propylene (PVdF-HFP) to obtain mechanically stable gel polymer electrolyte film (GPE) having maximum conductivity of ~10−3 S cm−1 at room temperature, which is acceptable from device fabrication point of view. Potential window and ionic transference number has been obtained to examine the potential limit and ionic characteristics of optimized GPE system. Temperature dependence behavior of electrical conductivity curve follows Arrhenius nature in the temperature range of 303–373 K. Pattern of dielectric constant and its loss as a function of frequency and temperature have been studied and is being explained on the basis of electrode interfacial polarization effect. Frequency-dependent conductivity spectra obey the Jonscher’s power law. Further, optimized composition of GPE has been tested successfully for its application in supercapacitor fabrication with activated charcoal as an electrode material. Maximum specific capacitance of 118.6 mF cm−2 equivalent to single electrode specific capacitance of 61.7 F g−1 have been observed for the optimized GPE film.

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4.
Yb3+-doped ceramic strontium cerate of exactly the composition SrCe0.95Yb0.05O3 − α was prepared, having a relative density of 99.0 (± 0.3%). Great care was taken to obtain homogeneous, carbonate free material. Analysis are made of the X-ray powder diffraction pattern of the as-prepared dense ceramic, resulting in the orthorhombic unit cell parameters a = 6.997(2) Å, b = 12.296(3) Å, c = 8.588(2) Å, Z = 8 and dx = 5.806(2) g cm−3. Bending strength values of the ceramic in non-proton and proton conducting state are found to be 177 and 194 MPa respectively. The ceramic kept under proton conducting conditions for 500 h at 300 °C to 800 °C in a N2 flow containing 155 mbar water vapour and 245 mbar H2, have shown to remain chemically and structurally stable. Impedance spectroscopy measurements of the bulk conductivity of the proton conducting ceramic revealed an activation energy of 53.2 kJ mol−1 and a preexponential factor of 359.1 (Ω cm)−1 K. In the non-proton conducting state the ceramic is mainly oxygen ion vacancy conducting, which indicates that charge compensation on substituting Yb+3 in SrCeO3 takes place by oxygen ion vacancies.  相似文献   

5.
A new lithium vitreous electrolyte has been found in the LiI---Li2S---P2S5 system. LiI concentration in the glass, 45% moles, is close to the solubility limit of LiI in 2Li2S---P2S5 glass.The activation energy is of the order of 7.2 Kcal.mole−1 and the conductivity value is 10−3 (ohm cm)−1 at 25°C. The conduction is ionic and assured by Li+ ions.  相似文献   

6.
This paper describes, nanocomposite polymer electrolyte (NCPE) based on polyvinylidenefluoride-co-hexafluoropropylene (PVdF-HFP), which comprises the novel lithium difluoro(oxalato)borate (LiDFOB). Ehtylene carbonate (EC) and diethyl carbonate (DEC) mixture was used as gelling agent and nanoparticulate TiO2 used as filler. The NCPE membranes were subjected to a.c. impedance, tensile strength, Raman studies, TG/DTA and morphological studies. 5 wt% TiO2 comprising membranes exhibited enhanced conductivity of 0.56 mS cm−1and the Young’s modulus was increased from 1.32 to 2.74 MPa. The structural change of α to β phase was confirmed by Raman studies. The thermal stability of the NCPE membrane is found to be 130 °C. Calculation of activation energy and synthesis of LiDFOB has also been presented.  相似文献   

7.
The preparation and characterization of the spinel LiMn2O4 obtained by solid state reaction from quasi-amorphous -MnO2 is reported. A well-defined highly pure spinel was characterized from X-ray diffractograms. The average manganese valence of -MnO2 and spinel samples was found to be 3.89±0.01 and 3.59±0.01, respectively. The electrochemical performance of the spinel was evaluated through cyclic voltammetry and chronopotentiometry. The voltammetric profiles obtained at 1 mV/s for the LiMn2O4 electrode in 1 M LiClO4 dissolved in a 2:1 mixture of ethylene carbonate and dimethyl carbonate showed typical peaks for the lithium insertion/extraction reactions. The charge capacity of this electrode was found to be 110 mA h g−1 for the first charge/discharge cycles.  相似文献   

8.
S. A. Hashmi  H. M. Updahyaya 《Ionics》2002,8(3-4):272-277
Redox supercapacitors using electrochemically synthesised MnO2-polypyrrole composite electrodes have been fabricated with different electrolytes, namely polymer electrolyte film (polyvinyl alcohol, PVA-H3PO4 aqueous blend), aprotic liquid electrolyte (LiClO4-propylene carbonate, PC) and polymeric gel electrolyte [poly methyl methacrylate, (PMMA)-Ethylene carbonate (EC)-Propylene carbonate (PC)-NaClO4]. The capacitors have been characterised using galvanostatic charge-discharge methods. The cell with aqueous PVA-H3PO4 shows non-capacitive behaviour owing to some reversible chemical reaction of MnO2 with water while the MnO2-polypyrrole composite is found to be a suitable electrode material for redox supercapacitors with aprotic (non-aqueous) electrolytes. The solid state supercapacitor based on MnO2-polypyrrole composite electrodes with gel electrolyte gives stable values of capacitance of 10.0–18.0 mF cm−2 for different discharge current densities.  相似文献   

9.
The role of charge carriers in ZnO2/CuO2 planes of Cu0.5Tl0.5Ba2Ca3Cu4−yZnyO12−δ material in bringing about superconductivity has been explained. Due to suppression of anti-ferromagnetic order with Zn 3d10 (S=0) substitution at Cu 3d9 sites in the inner CuO2 planes of Cu0.5Tl0.5Ba2Ca3Cu4O12−δ superconductor, the distribution of charge carriers becomes homogeneous and optimum, which is evident from the enhanced superconductivity parameters. The decreased c-axis length with the increase of Zn doping improves interlayer coupling and hence the three dimensional (3D) conductivity in the unit cell is enhanced. Also the softening of phonon modes with the increased Zn doping indicates that the electron–phonon interaction has an essential role in the mechanism of high-Tc superconductivity in these compounds.  相似文献   

10.
Bi4−xMxV2O11 (M = La, Gd) was prepared by solid state reactions. The amount of La and Gd in the (Bi4−xMxV2O11) was varied in the range of (0 x 0.4). The addition of La and Gd to Bi4V2O11 electrolyte was found to stabilize the β crystalline phase for x 0.3. In addition, the phase transition corresponding β- to γ-phases are evident in the ionic conductivity plots as well as in XRD, DSC profiles of x 0.3 samples. The highest ionic conductivity was observed in Bi3.9La0.1V2O11 and Bi3.8Gd0.2V2O11 samples in the range of 10−3–10−4 S/cm for 700–500 °C. These results were supported by impedance spectroscopy, X-ray diffraction (XRD) and differential scanning calorimetry (DSC).  相似文献   

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