Temperature Dependent Conductivity Plot Research Articles

Influence of synthesis methodology and excess Na on the ionic transport properties of natrium super ionic conductor, Na3Zr2Si2PO12

Na3Zr2Si2PO12 is a well-known solid electrolyte because of its potential applications in Na-ion batteries and gas sensors. In this work, the structural and transport properties of Na3Zr2Si2PO12 synthesized by solid-state reaction and sol–gel techniques are compared. In both methods, a monoclinic phase for Na3Zr2Si2PO12 is confirmed by X-ray Diffraction and FTIR spectroscopy techniques. The impedance measurements show higher conductivity in Na3Zr2Si2PO12 prepared by solid-state reaction. The role of sintering temperatures on the transport results of Na3Zr2Si2PO12 has been investigated. The temperature dependent conductivity plots of Na3Zr2Si2PO12 show a change in the slope at 163 °C corresponding to its structural phase transition from monoclinic to rhombohedral form, which is further supported by its DSC result. Furthermore, the role of excess Na on the ionic conductivity of Na3Zr2Si2PO12 using two different Na precursors Na2CO3 and Na3PO4 keeping same Na-stoichiometry has been investigated.

Nanocomposite polymer gel with dispersed alumina as an efficient electrolyte for application in supercapacitors

A nanocomposite polymer gel electrolyte (NCPGE) has been synthesized from polyvinylidene fluoride co-hexafluoropropylene (PVDF-HFP) as the host polymer, ethylene carbonate (EC)/propylene carbonate (PC) as plasticizers, and tetraethylammonium tetrafluoroborate (TEABF4) as an ionic salt by a solution-casting technique, followed by the addition of Al2O3 nanoparticles. The optimal loading of Al2O3 giving the highest ionic conductivity of 6.0 × 10−3 S cm−1 was found to be 18 wt%. An activation energy of 0.107 eV has been calculated from a temperature-dependent conductivity plot, which shows Arrhenius behavior. Scanning electron microscopy (SEM), X-ray diffraction (XRD), and Fourier-transform infrared (FTIR) characterizations have been applied to investigate the morphology and structure. The semi-crystalline and porous nature of the NCPGE has been confirmed by SEM and XRD analyses. The ionic transference number was calculated as 0.98 by the DC polarization technique, confirming the dominant ionic nature of the prepared electrolyte. The electrochemical potential window of the NCPGE of about 3.4 V, as estimated by linear sweep voltammetry, makes it suitable for supercapacitor applications.

Structural, dielectric and electrical properties of bismuth magnesium tantalate electronic system

Abstract The lead-free dielectric compound Bi(Mg2/3Ta1/3)O3 (BMT) has been synthesized at high temperature by a low-cost solid-state method. The X-ray diffraction (XRD) technique reveals that the fabricated sample has an orthorhombic crystal system. The scanning electron microscope (SEM) image displays the uniform distribution of grains on the surface of the specimen. The dielectric parameters (permittivity (er), and loss tangent (tan δ) are studied over a wide range of temperature (150–500 °C) and frequency (1 kHz–1 MHz). The temperature dependent conductivity plot follows Universal Johnson's power law. The complex impedance and modulus spectrum illustrate the electrical behavior of the compound at various frequency and temperature. The Nyquist spectra show the presence of the effect of grain and grain boundary in the synthesized compound. The grain resistance value declines with the rise in temperature that shows the presence of a negative temperature coefficient (NTCR) behavior in the compound. The complex modulus spectra display the occurrence of the conduction mechanism in the specimen. The reported compound has a relative dielectric constant and loss of 22 × 103 and 1.8 respectively at 1 kHz frequency and 500 °C, thus becoming an efficient applicant for dielectric applications that can operate at higher temperatures.

Studies of structural, electrical, and excitation performance of electronic material: europium substituted 0.9(Bi0.5Na0.5TiO3)–0.1(PbZr0.48Ti0.52O3)

The polycrystalline samples having composition Bi0.45Eu0.02Na0.45Pb0.1Zr0.048Ti0.952O3 (BNPZTE-2 abbreviated ahead), Bi0.41Eu0.04Na0.45Pb0.1Zr0.048Ti0.952O3 (BNPZTE-4 abbreviated ahead), Bi0.39Eu0.06Na0.45Pb0.1Zr0.048Ti0.952O3 (BNPZTE-6 abbreviated ahead) had been synthesised using the mixed oxide processing route. The prepared samples were found to be in single phase and crystallize in tetragonal structure. The surface morphology suggests the high density grain growth in all samples. The electrical behavior (dielectric, impedance, and modulus) of the prepared samples collected at various temperatures and frequencies. The value of activation energy had been evaluated from the temperature dependent conductivity plot. The grain and grain boundary contribution to the polarization process have been depicted from the impedance analysis. The parallel plate capacitor structure was proposed to unveil the influence of applied electric field on the excitation of samples. The prepared samples will find its application in the filter application (noise removal) or buffering circuit.

Zinc oxide nanofiller-based composite polymer gel electrolyte for application in EDLCs

A ZnO nanofiller-based polymer gel electrolyte was prepared using solution-cast technique by incorporating PVDF-HFP as the polymer, ethylene carbonate (EC)-propylene carbonate (PC) as plasticizers, tetraethylammonium tetrafluoroborate (TEABF4) as salt, and ZnO as nanofiller. A maximum ionic conductivity value 6.3 × 10−3 Scm−1 was obtained by adding 12 wt% of ZnO nanoparticles in complex [{PVDF-HFP (20 wt%) + {EC-PC (v/v)-TEABF4 (1.0 M)} (80 wt%)}]. From the temperature-dependent conductivity plot, the activation energy is found to be equal to Ea ~ 0.07 eV. The amorphous structure is confirmed by SEM and XRD analysis. Electrochemical potential window and ionic transference number were calculated and found to be equal to ~3.3 V and 0.84, respectively. Optimized NCPGE is utilized in the fabrication of the electrical double-layer capacitor (EDLC) cell using market parched activated charcoal as electrode material. The specific capacitance of the fabricated EDLC cell is found to be equal to 162.9 mFcm−1 and ~ 67.8 Fg−1 for the single-electrode system.

Mechanical milling: An alternative approach for enhancing the conductivity of SnF2

SnF2 of various crystallite sizes have been obtained by mechanical milling. Further, the crystallite size dependent conduction characteristics of SnF2 have been investigated by X-Ray Diffraction, High Resolution Scanning Electron Microscopy and Impedance Spectroscopy techniques. The crystallite size and microstrain developed during the milling process have been calculated by using Scherrer's semi-empirical formula. Further, an attempt is made to correlate the conductivity results of mechanically milled samples with the crystallite size and microstrain. In all cases, the temperature dependent conductivity plot obeys the Arrhenius behavior. The enhancement in conductivity of SnF2 is found to be of two orders of magnitude after simply milling for 10h.

AC conductivity and scaling studies of polycrystalline SnF 2

The conduction characteristics of SnF 2 from room temperature (300 K) to 463 K have been investigated by using impedance spectroscopy. The temperature dependent conductivity plot shows a break in conductivity around 443 K corresponding to the α → γ phase transition temperature. The electrical properties of SnF 2 are also investigated by extracting dielectric and modulus data from impedance values. The frequency dependent plots of M″ and Z″ show that the conductivity relaxation is non-Debye in nature. The activation energy responsible for relaxation has been calculated from the modulus spectra and is found to be almost the same as that from the temperature dependent dc conductivity data. The real part of conductivity and permittivity in addition to the modulus spectra of the present system show scaling behavior, which means σ′( ω), ɛ′( ω) and M′( ω) isotherms successfully collapse to a single master curve indicating that the relaxation mechanism is temperature independent. Different scaling approaches have been applied to arrive at a correlation between the scaling parameters.