Argand Plots Research Articles

Study of dielectric and interfacial properties of functional biopolymer-based electrolyte with enhanced conductivity for energy storage application

This study investigates sodium (Na+) ion-conductive biopolymer blend electrolytes with glycerol as a plasticizer for energy storage. Through FTIR, impedance spectroscopy, transference number measurement (TNM), and linear sweep voltammetry (LSV), we identify an optimal film for electric double layer capacitor (EDLC) application. Glycerol induces notable changes in polymer-salt interaction, evidenced by FTIR band shifts reflecting increased free ions. Impedance measurements show reduced bulk resistance with optimal plasticizer content, emphasizing the system's suitability for energy storage. The system exhibits high real permittivity relative to imaginary at lower frequencies, attributing to glycerol's dielectric constant and small bulk resistance. Loss tangent (tanδ) and Argand plots reveal the dominant ion conduction mechanism. Electrochemical assessments support the suitability of the film for EDLC applications, featuring a favorable transference number (tion = 0.94) and high decomposition voltage (2.6V). Cyclic voltammetry (CV) curves demonstrate effective EDLC device design with significant capacitance adaptability across varying scan rates (5.946 F/g to 24.074 F/g).

Effect of the boson peak and the ionic resonance in the dielectric properties of silicate materials at mm-wave and THz frequencies

In this paper, a broadband measurement of the dielectric properties of silicates has been done to cover the seldom characterized mm-wave spectrum and the low THz spectrum. The dielectric properties, i.e. loss and permittivity, show a frequency independent response up to approximately 40 GHz and the loss monotonically increases to the THz frequency range. Two resonance peaks appear at THz frequencies: the first is the boson peak, and the second one corresponds to the ionic resonance of the network former, which in this case is silicon. Even though the materials belong to different groups in the silicate family (crystalline and non-crystalline, with different levels of purity), they seem to have the same overall tendency in the dielectric properties. Argand plots are used for the first time at THz frequencies to provide physical insight into the boson peak and ionic resonance. The complex plane analysis reveals details on the polarization mechanisms underlying silicate network vibrations through direct visualization of their characteristic signatures, and simplifies the process of modeling the dielectric response, leading to a better fit.

Preparation and characterization of proton (H+) conducting solid blend polymer electrolytes based on PEO/P(VdF-HFP) incorporated with NH4SCN

A new H+ ion-conducting solid blend polymer electrolytes system comprising of Poly (ethylene oxide) (PEO) and Poly (vinylidene fluoride-co-hexafluoropropylene) P(VdF-HFP) and ammonium thiocyanate (NH4SCN) have been prepared using solution casting technique. The X-Ray Diffraction (XRD) study demonstrates that there is a decrease in crystalline peaks of polymer electrolytes by increasing NH4SCN salt. FT-IR analysis confirms the interaction between polymers and salt. Using complex impedance spectroscopy, electrical characteristics have been determined with a 42Hz to 1MHz frequency range. The electrical conductivity varies with temperature and shows Arrhenius behaviour. The activation energy decreases as the salt content is increased. Frequency-dependent conductivity, dielectric permittivity (ε′) modulus (M′), and Loss tangent (tanδ) analysis of the prepared polymer electrolytes is also carried out. Argand plots are used to investigate the dynamics of ion relaxation. To analyze the electrochemical behaviour of the electrolytes, linear sweep voltametric (LSV) and cyclic voltametric (CV) measurements are performed. Thus, it is confirmed that the prepared polymer electrolytes are suitable for energy storage devices.

AC Susceptibility Studies of Magnetic Relaxation in Mn12-Stearate SMMs on the Spherical Silica Surface

The study of magnetic relaxations in Mn12-stearate single-molecule magnets deposited on the surface of spherical silica nanoparticles was performed. For such a purpose, the investigation of AC magnetic susceptibility dependence on the frequency and temperature was performed. Based on the Argand plots obtained for different temperatures and temperature dependencies of susceptibility, obtained for different frequencies of AC field, the corresponding relaxation times were derived. Fitting to the Arrhenius law revealed the values of an effective energy barrier and a mean relaxation time, which were consistent for both measuring techniques (Ueff/kB∼ 50 K and τ0∼ 10−7 s) and similar to the corresponding values for the analogous bulk compounds. Additionally, the obtained relaxation parameters for the Mn12-stearate molecules on the spherical silica surface were compared with corresponding values for the Mn12-based single-molecule magnets deposited upon other types of nanostructured silica surface.

Preparation and characterization of CuO/Co3O4/poly(methyl methacrylate) nanocomposites for optical and dielectric applications

Composites of transition metal oxides (TMOs)/polymers have many modern technological, industrial, and biological applications. Co3O4 and CuO nanoparticles (Nps) were synthesized by sol–gel. Then they are doped into poly(methyl methacrylate) (PMMA) via the solution casting method. The obtained Nps and nanocomposites were then investigated using several techniques. XRD and HR-TEM indicated the high purity of Co3O4 and CuO Nps of face-centered cubic (fcc) with 58 nm average particle size (Dav), and monoclinic structure with Dav = 35 nm, respectively. The amorphous nature of PMMA was influenced after mixing with these Nps. SEM and FTIR confirmed the interaction between Nps and the polymer chains. The pure sample showed transparency of about 90% and Nps addition narrowed the optical bandgap effectively while keeping the samples with high transmittance. CuO is more effective than Co3O4 on the optical parameters of the nanocomposites. The dielectric constant improved after adding the Nps, while all samples have a low dielectric loss. Additionally, the effects of Co3O4 and CuO on the ac conductivity, conduction mechanism, Argand plots, and the dielectric modulus are reported. Our nanocomposites are considered a promising candidate for nanotechnology-based devices such as electric stress control, film capacitors and anti-reflective coating for solar cell applications.

Study of dielectric relaxation and polaron conductivity mechanism in sodium nitroprusside (SNP): Na2[Fe(CN)5(NO)]·2H2O

In this study, the crystal structure of sodium nitroprusside, Na 2 [Fe(CN) 5 (NO)]·2H20, has been determined by an analysis by X-ray diffraction (XRD). The crystal is orthorhombic, space group Pnnm. This compound is characterized by different techniques: X-ray diffraction (XRD), differential scanning calorimetry (DSC) and impedance spectroscopy. For electrical properties, impedance spectroscopy was performed at a frequency range of 20 Hz–2 MHz. The dependence of AC conductivity on frequency was found to satisfy Jonscher's universal power law at different temperatures σ ( ω ) = σ D C ( ω , T ) + A ω S ( T , ω ) . This suggested hoping conduction due to three theoretical models. The latter can be attributed to the correlated barrier hopping (CBH) model in region I, overlapping large polaron tunneling (OLPT) in region II and non-overlapping small polaron tunneling (NSPT) mechanism in region III. The temperature dependence and dielectric relaxation of the DC conductivity satisfied the Arrhenius law. The activation energy ranged from 0.033 to 0.164 eV and was similar in the conduction and relaxation mechanisms, indicating that the transport mechanisms were based on hopping phenomena. Moreover, the modulus plots has been characterized by full width at half height or in terms of a non-experiential decay function ϕ(t) = exp(−t/τ)β. The values of the activation energies obtained from the electrical conductivity and electric modulus are near; which suggests that the transport is probably due to the ion hopping mechanisms. Furthermore, this behavior was confirmed by both Nyquist and Argand's plots of dielectric impedance at different measuring temperatures. Crystal structure, Molecular Hirshfeld surfaces, hydrogen bonding, UV absorption and phase transition of the β-NH 3 (CH 2 ) 2 NH 3 SnCl 6 compound. • This compound is crystallized in the orthorhombic system (Pnnm space group). • Differential scanning calorimetric (DSC) experiments show a phase transition at 130 K and 155 K. • The conduction mechanism is attributed to the (CBH) model, (OLPT) and (NSPT) mechanism. • The activation energies suggest that the transport is probably due to the ion hopping mechanisms. • The near value of activation energies obtained from the analysis of M.

Impedance and ionic transport properties of proton-conducting electrolytes based on polyethylene oxide/methylcellulose blend polymers

Abstract Proton-conducting polymer electrolyte films were prepared by dissolving NH4I salt in polyethylene oxide/methylcellulose (PEO/MC) blend polymers using the solution cast technique. The semi-crystalline nature of the sample was identified from the X-ray diffraction (XRD) pattern. The surface morphology on the electrical conductivity was analyzed by scanning electron microscopy (SEM). The highest ionic conductivity of 7.62 × 10 − 5 S / c m was achieved at room temperature for the sample containing 30 wt. % of NH4I. The temperature dependence of the Jonscher's exponent shows that the conduction mechanism can be well represented by the overlapping large polaron tunneling (OLPT) model. The electrical conductivity enhancement was analyzed by the Rice and Roth model, which showed that the increase in the salt concentration caused an increment in the mobility and the diffusion coefficient of the ions. For all prepared samples, the highest value of conductivity was associated with the minimum value of activation energy. The dielectric data were analyzed for the highest ionic conducting sample at various temperatures to clarify an important factor of the ion conduction. The non-Debye behavior of the samples can be expressed from the electric modulus formalism and the dielectric properties of the electrolytes that have been proven by the incomplete semicircular arc of the Argand plots.

Spectroscopic, Optical and Dielectric Investigation of (Mg, Cu, Ni, or Cd) Acetates’ Influence on Carboxymethyl Cellulose Sodium Salt/Polyvinylpyrrolidone Polymer Electrolyte Films

Solid polymer electrolytes, which have a low bandgap and a high dielectric constant, are an interesting technology for optoelectronic applications and supercapacitors. This work studies the influence of Mg, Cu, Ni or Cd acetates on the structural and optical properties and the dielectric relaxation phenomena in carboxymethyl cellulose sodium salt (CMC)/polyvinylpyrrolidone (PVP) blends. The dielectric behavior, ac conductivity and electrical modulus formalism were investigated in a frequency range of up to 1 MHz at room temperature. X-ray diffraction energy dispersive x-ray, Fourier transform infrared spectroscopy and scanning electron microscopy, revealed modifications of the films’ structural and chemical compositions and their morphology. UV–Vis and dielectric properties measurements revealed that the Cu and Mg salts had more distinctive influences on the optical properties, ac conductivity ($$ \sigma_{\rm{ac}} ) $$ and relaxation behavior. Cu and Mg reduced the optical bandgap Eg of the CMC/PVP blends from 5.1 eV to 4.7 eV and 3.6 eV, respectively, but increased $$ \sigma_{\rm{ac}} $$ from 8.61 × 10−5 S/cm to 1.34 × 10−4 S/cm and 1.81 ×10−4 S/cm, respectively. The dielectric measurements revealed an increase in the dielectric constant and dielectric losses for the composite films, which reflect the enhancement of the dielectric polarization of the films. The electric modulus spectra, calculated relaxation time and Argand plots confirmed an improvement in the ionic conductivity of the composite films. These results indicate that the incorporation of the acetate salts is a simple approach to widening the technological importance of CMC/PVP blend films for some optoelectronic devices and Cu and Mg battery applications.

An effective and novel approach for enhancement of the oxidative thermal stability of multiwalled carbon nanotubes loaded polymer blend

Multiwalled carbon nanotubes (MWCNTs) have wide range of applications. Commercial MWCNTs have impurities, disorder and entangled structure, which limit its applications. In this respect, novel, low-energy consumption and friendly technique was applied to enhance its structure. The technique is operated during isometric process inside autoclave and based on thermal treatment of MWCNTs in the presence of solvent and pressure. It was used to enhance the oxidative thermal stability of MWCNTs. Thermal gravimetric analysis results showed an increase in onset temperature, activation energy of decomposition, and the temperature required to loss 75, 50, and 33 wt% as the treating temperature increased. Raman spectroscopy tests showed a decrease in the degree of disorder from 1.29 for untreated samples to 0.45 for samples treated at 250°C. The electrical resistivity of MWCNTs was increased from 0.33 Ω.cm for untreated samples to 0.54 Ω cm for 250°C treated samples. Advantages of thermal treatment of MWCNTs using this technique appeared in the presence of a percolation behavior for the AC electrical conductivity when a polymer matrix was loaded with it with a threshold percolation concentration of 0.7 wt%. Furthermore, Cole–Cole Z semicircles as well as Argand plots of the electric modulus appeared for polymer matrix loaded with thermally treated MWCNTs beyond the threshold percolation concentration.

Non suitability of silver ion conducting polymer electrolytes based on chitosan mediated by barium titanate (BaTiO3) for electrochemical device applications

In this study, we report the non-suitability of silver ion conducting polymer electrolytes mediated by barium titanate (BaTiO3) for electrochemical device applications. Various amounts of BaTiO3 fillers have been added to chitosan: silver triflate (CS:AgTf) solution to prepare polymer composites. Electrical impedance spectroscopy (EIS) has been used to characterize electrical properties of the samples. Charge transfer resistance has been correctly estimated for the samples using electrical equivalent circuit (EEC) model. At 3 and 5 wt % of BaTiO3 filler, the charge transfer resistance was found to increase and diameter of the impedance plots are shown to be widened due to the increase of grain boundaries. The dielectric constant is also observed to decrease with the increase of BaTiO3 concentration. DC conductivities for the composite samples are estimated from AC conductivity spectra. The DC conductivity was found to decrease from 4.7 × 10−7 S/cm to 5.4 × 10−9 S/cm for CS:AgTf system incorporated with BaTiO3 filler. Such decrease has revealed that the electrolytes are not suitable for electrochemical device applications. Shifting of relaxation peaks of imaginary part of electric modulus towards low frequency side has indicated the increase of relaxation time and hence the decrease in DC conductivity. The relaxation processes are also studied using Argand plots. The existence of metallic silver nanoparticles has been examined via ultraviolet–visible (UV–Vis) spectroscopy. The UV–Vis spectra showed that surface plasmon resonance (SPR) peaks are broadened and increased in their intensity as the BaTiO3 concentration increased from 1 to 3 wt %. This implied that the reduction rate of silver ions to silver nanoparticles is increased. Moreover, disappearance of SPR peak was found for the BaTiO3 concentration of 5 wt %, revealing the bulk formation of silver metals. Transmission electron microscopy (TEM) images were obtained for the samples, in which the formation of bulk metallic sizes of silvers was found to be obvious. This growth of bulk silver metals at high BaTiO3 concentration was further supported by optical and scanning electron microscopy (SEM) techniques. The distribution of white specs due to silver nanoparticles on the surface of chitosan-silver triflate solid film was investigated. Large white sheets were appeared on the surface of CS:AgTf incorporated with 5 wt% BaTiO3 and related to the huge amount of aggregated metallic silver particles. Sharp intense peaks due to metallic silver particles and weak peaks due to BaTiO3 fillers have been observed in the analyses of energy dispersive X-ray (EDX) spectra.

Enhancement of spectroscopic, thermal, electrical and morphological properties of polyethylene oxide/carboxymethyl cellulose blends: Combined FT-IR/DFT

Different ratios between polyethylene oxide (PEO) and carboxymethyl cellulose (CMC) blends were prepared through the solution casting technique. The X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), thermogravimetric analysis (TGA), dielectric spectroscopy and scanning electron microscopy (SEM) were used to investigate the blends. The XRD results confirmed the semicrystalline nature of PEO and amorphous nature of CMC, respectively. The intensity of XRD was changed with varying ratios in the blends. The FT-IR spectra of PEO/CMC blends exhibited all characteristic vibrational spectral bands with variations in their intensities depicting interaction attributed to hydrogen bond in the polymers. Density Function Theory (DFT) was utilized to study the theoretical interaction process for PEO/CMC and indicated that the prepared blends had unique hydrogen bonding. TGA curves indicated that the thermal stability of prepared blends was changed. The Coats-Refern's model was used to calculate the thermal activation energy. The AC electrical conductivity and the dielectric behaviors in these blends were studied using the dielectric relaxation at different frequencies. Argand plots showed half semicircle which depicts the Debye-type relaxation process. The morphology from the scanning electron microscope (SEM) reveals that the degree of miscibility significantly improves as CMC content increases within the PEO/CMC blend matrix.

Capacitance–Resistive PEDOT:PSS Cotton Fabric Satisfied Jonscher’s Law with Index Exceeding One

Jonscher’s law is investigated in the context of PEDOT:PSS impregnated conductive cotton fabric for frequencies from 10 Hz to 13 MHz and temperatures from 30°C to 100°C using complex impedance spectroscopy. The drop-casting and drying method was used to prepare samples of conductive cotton fabric with low and high concentrations of dopant. Argand plots of the ratio of AC–DC conductivities of the conductive fabric demonstrated the presence of reactance at high frequencies at each concentration of dopant. Regression analysis demonstrated that Jonscher’s power law was obeyed over a significant range of high frequencies. The hopping frequency and Jonscher index are found to depend on the concentration of dopant, but are insensitive to temperature over the range used in this study. By contrast with numerous experimental studies reporting that the Jonscher index is less than one, this experimental investigation found that Jonscher’s index exceeded one. We further investigated whether or not the hopping frequency identified by regression corresponded to a natural frequency arising in the Argand plot of the complex conductivity ratio. Considerations of curvature and phase angle identified two candidate frequencies, but neither was close to the hopping frequency identified by regression.

Riccati Parametric Deformations of the Cornu Spiral

Abstract In this article, a parametric deformation of the Cornu spiral is introduced. The parameter is an integration constant which appears in the general solution of the Riccati equation and is related to the Fresnel integrals. The Argand plots of the deformed spirals are presented and a supersymmetric (Darboux) structure of the deformation is revealed through the factorization approach.

The Mixed Contribution of Ionic and Electronic Carriers to Conductivity in Chitosan Based Solid Electrolytes Mediated by CuNt Salt

This work shows the contribution of both ionic and electronic conductivities in chitosan (CS) based solid polymer electrolytes incorporated with various amounts of copper nitrate (CuNt). The samples were prepared using solution cast technique. The second semicircles at intermediate frequency in impedance plots were observed. Surface plasmonic resonance (SPR) was illustrated from the UV–Vis spectrophotometry, where broad peaks at 702 nm were obtained as an evidence for nanoparticles formation. The second semicircles in the impedance plots and the distinguished SPR peaks have revealed the contribution of electronic conductivity in CS:CuNt based polymer electrolytes. The same trend of UV–Vis spectra at different temperatures reveals that CS:CuNt polymer electrolyte is thermally stable. The presence of electronic conductivity is the main shortcoming of copper ion conducting solid polymer electrolytes. The role of lattice energy of the copper salts on electrical properties and morphological (SEM) appearance was discussed. The TEM image shows Cu nanopartciles with various sizes. A stable SPR peak and vanishing of second semicircle at high temperatures reveals the stability of copper ion conducting chitosan based polymer electrolytes. The pattern of DC conductivity and dielectric constant as a function of salt concentration are almost found to be similar. Both estimated DC conductivities from AC spectra and those calculated from impedance plots are shown to be comparable. Highest DC conductivity of 3.65 × 10−5 S/cm has been achieved for the sample incorporated with 21 wt% of CuNt. The high value of dielectric constant at low frequency can be ascribed to electrode polarization. Electric modulus parameters are studied to understand the relaxation process. Two semicircles in Argand plots were separated.

Effect of annealing temperature on structural, morphology and dielectric properties of La0.75Ba0.25FeO3 perovskite

The effect of annealing temperature on the structure, morphology and dielectric properties of La0.75Ba0.25FeO3 compound prepared by the sol-gel method was investigated. The increase of the annealing temperature from 900 to 1100 °C, promotes an increase of the average grain size value. Two dielectric relaxations are detected using the dielectric modulus formalism, attributed to grain and grain boundary relaxations. This behavior was confirmed by both Nyquist and Argand's plots of dielectric impedance and Modulus results at different measuring temperatures. The ac conductivity could be described by Jonscher's power law revealing the presence of both overlapping large polaron tunneling and non-overlapping small polaron tunneling mechanisms.

Li‐ion conductivity in PEO‐graphene oxide nanocomposite polymer electrolytes: A study on effect of the counter anion

ABSTRACTGraphene oxide (GO) has been prepared by modified Hummer's method for their incorporation as nanofiller in designing nanocomposite polymer electrolytes (NCPEs). Prior to use the GO nanofillers has been characterized by TEM, FTIR, and Raman studies to elucidate their nanostructure, functionality, and purity. The various poly(ethylene oxide) (PEO)‐based NCPEs has been prepared by incorporating GO nanofillers in presence of three different lithium salts, viz., CF3SO3Li, LiTFSI, and LiNO3 as the source of Li‐ions and then casted into free standing polymeric films. The change in PEO crystallinity has been studied considering their full width half maximum values of respective diffraction peaks in the XRD spectra. The Li‐ion conductivity of various NCPEs has been studied from impedance spectroscopy. All the NCPE films show optimum value of Li‐ion conductivity with 0.3% GO nanofiller content irrespective of the source of Li‐ions used. But, variation of the Li‐ion conductivity values is occurred for all the three studied lithium salts. Both LiTFSI and LiNO3 salts display Li‐ion conductivity in the order of 10−4 S cm−1 whereas CF3SO3Li in the order of 10−6 S cm−1, all in presence of 0.3% GO nanofillers. The change in conductivity values of the NCPEs has been explained by correlating with Argand plots and also with change in PEO crystallinity, which occurs due to various relaxation processes. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 46336.

Nanostructure PEO‐Silica Hybrids: A New Class of Additive Material for Composite Polymer Electrolytes

AbstractHybrid nanostructure polyethylene oxide (PEO)‐silica hybrids (PSH) prepared by sol‐gel chemistry are utilized as novel nanofiller to fabricate PEO‐based nanocomposite polymer elecytrolytes (NCPEs) by adopting the conventional solvent casting approach. The resulting PSH hybrids are characterized by various techniques followed by their incorporation into NCPEs that result in enhancement in the Li‐ion conductivity and a maximum ionic conductivity of 7.20 × 10−5 S cm−1 is achieved with only 0.25% nanofillers. The temperature dependence conductivity study shows a linear behavior below melting temperature following the Arrhenius equation and shows non‐linear behavior above the melting temperature following the Vogel–Taumann–Fulcher (VTF) equation. Argand plots of various NCPEs both at room temperature and elevated temperature signify the role of various relaxation processes for such type of conducting behavior, which is further supported by dielectric and tangential loss studies. Moreover, X‐ray diffraction and Differential Scanning Calorimetry measurements are carried out to understand the change in polymer crystallinity in the resulting NCPEs and are well in accordance with the conductivity changes.

Effect of PVA Blending on Structural and Ion Transport Properties of CS:AgNt-Based Polymer Electrolyte Membrane.

In this work, the role of poly(vinyl alcohol) (PVA) blending on structural and electrical properties of chitosan:silver nitrate systems is studied. The X-ray diffraction (XRD) results show that the crystalline phase of chitosan (CS) is greatly scarified by silver nitrate (AgNt) salt. The crystalline domain of CS:AgNt is more broadened at 10 wt % of PVA. The spike and semicircular arcs can be separated in impedance plots. At high temperatures, the spike regions remained. The direct current (DC) conductivity was calculated from the bulk resistance obtained from the impedance plots. The dielectric constant and DC conductivity versus PVA content exhibited similar behavior. The maximum DC conductivity at ambient temperature was 1.1 × 10−6 S/cm for 10 wt % of PVA. The DC ionic conductivity increased to 9.95 × 10−5 S/cm at 80 °C. Above 10 wt % of PVA, the drop in DC conductivity and dielectric constant were observed due to the increase in viscosity. Shifting of relaxation peaks towards the lower frequency revealed the increase of resistivity of the samples. The linear increase of DC conductivity versus 1000/T indicated that ion transport followed the Arrhenius model. The incomplete semicircular arc in Argand plots indicated the non-Debye type of relaxation process. The Argand plots were used to distinguish between conductivity relaxation and viscoelastic relaxation. Three regions were distinguished in the alternating current (AC) spectra of the blend electrolyte samples. The plateau region in AC spectra was used to estimate the DC conductivity. The estimated DC conductivity from the AC spectra was close to those calculated from the impedance plots.

Occurrence of electrical percolation threshold and observation of phase transition in chitosan(1−x):AgI x (0.05 ≤ x ≤ 0.2)-based ion-conducting solid polymer composites

This paper reports on the investigation of electrical percolation threshold and ion transport mechanism for ion-conducting solid polymer composites based on chitosan. The composite samples were prepared by solution cast technique. The result of DC conductivity versus percolation threshold (\(\varPhi^{ - 1/3}\) ) confirmed that at low AgI concentration, the tunneling effect governs ionic conduction mechanism. Nevertheless, at high filler concentration, the DC conductivity showed a plateau behavior. The DC conductivity as a function of reciprocal temperature revealed that the ion conduction mechanism is slightly temperature dependent and the ion–ion correlational effect is dominant. A steep increase in DC conductivity above 323 K is observed, which indicated the existence of some phase transition near the beta (β)-phase. The drop of DC conductivity at high temperatures is anticipated from the impedance plots. The AC conductivity spectrum exhibited three distinct regions at low temperatures. The high-frequency regions of AC conductivity spectra were almost temperature independent at low temperatures (303–323 K) and obeyed the Jonscher’s power law. The variation in frequency exponent versus temperature reveals that ion conduction mechanism follows QMT and CBH models at low and high temperatures, respectively. The valuable achievement of this work is that the temperature dependence of DC conductivity and the frequency exponent (s) is correlated to interpret the Ag+ ion dynamic and ion–ion correlational effect. The Argand plots were used to explain the relaxation processes.

Role of Dielectric Constant on Ion Transport: Reformulated Arrhenius Equation

Solid and nanocomposite polymer electrolytes based on chitosan have been prepared by solution cast technique. The XRD results reveal the occurrence of complexation between chitosan (CS) and the LiTf salt. The deconvolution of the diffractogram of nanocomposite solid polymer electrolytes demonstrates the increase of amorphous domain with increasing alumina content up to 4 wt.%. Further incorporation of alumina nanoparticles (6 to 10 wt.% Al2O3) results in crystallinity increase (large crystallite size). The morphological (SEM and EDX) analysis well supported the XRD results. Similar trends of DC conductivity and dielectric constant with Al2O3concentration were explained. The TEM images were used to explain the phenomena of space charge and blocking effects. The reformulated Arrhenius equation (σ(ε′,T)=σoexp(-Ea/KBε′T)) was proposed from the smooth exponential behavior of DC conductivity versus dielectric constant at different temperatures. The more linear behavior of DC conductivity versus1000/(ɛ′×T)reveals the crucial role of dielectric constant in Arrhenius equation. The drawbacks of Arrhenius equation can be understood from the less linear behavior of DC conductivity versus1000/T. The relaxation processes have been interpreted in terms of Argand plots.