Concentration Dependence Of Conductivity Research Articles

The Role of Adsorption Phenomena in ac Conductivity Measurements of Dielectric Nanoparticle Suspensions

The authors of numerous measurements of conductivity for suspensions of nanoparticles of various types carried out in the last decade came to the general conclusion that the well-known Maxwell’s theory is not applicable to quantitative explanation of the properties of such systems. In the present work, we demonstrate that the Maxwell’s theory can be still applicable even for such systems, but the specifics of the standard ac measurements have to be correctly taken into account. Namely, the dependence of the capacitance of “metal–electrolyte” cuvette boundaries on nanoparticle adsorption, which in its turn dramatically depends on nanoparticle concentration, has to be taken into account. The latter circumstance strongly (via the RC characteristic of the circuit) affects the results of conductivity measurements. We propose the new algorithm of the impedance measurement data analysis for the particles’ concentration dependence of conductivity σ(ϕ) (where ϕ is the volume fraction of nanoparticles in suspension) for the suspensions of the diamante nanoparticles in alcohol which demonstrates the adequate correspondence of the Maxwell’s theory to the available experimental findings.

Ion Conductivity in Salt-Doped Polymers: Combined Effects of Temperature and Salt Concentration.

We construct a coarse-grained molecular dynamics model based on poly(ethylene oxide) and lithium bis(trifluoromethane)sulfonimide salt to examine the combined effects of temperature and salt concentration on the transport properties. Salt doping notably slows the dynamics of polymer chains and reduces ion diffusivity, resulting in a glass transition temperature increase proportional to the salt concentration. The polymer diffusion is shown to be well represented by a modified Vogel-Fulcher-Tamman (M-VFT) equation that accounts for both the temperature and salt concentration dependence. Furthermore, we find that, at any temperature, the concentration dependence of the conductivity is well described by the product of its infinite dilution value and a correction factor accounting for the reduced segmental mobility with increasing salt concentration. These results highlight the important role of polymer segmental mobility in the salt concentration dependence of ion conductivity for temperatures near and above the glass transition.

Effectiveness of Maxwell velocity and smoluchowski thermal slip constraints in presence of non-uniform heat source

Magnetohydrodynamic flow of nanomaterial by a stretched boundary is addressed. Entropy generation is examined. Variable fluid characteristics are considered. Buongiorno thermal enhancement model in presence of Darcy-Forchheimer expression is addressed. Nonlinear thermal radiation, non-uniform heat source and dissipation are considered in thermal expression. Slip conditions in chemically reactive flow are addressed. Here Maxwell slip velocity and Smoluchowski slip temperature are under consideration. Impact of Arrhenius activation energy is deliberated. Optimal homotopy analysis approach (OHAM) is utilized for construction of convergent solutions. Graphical description for liquid motion, entropy rate, concentration and temperature are examined. Higher magnetic variable has reverse effect on entropy rate and velocity. Higher temperature and entropy rate are seen for radiation parameter. Higher temperature dependent conductivity parameter has opposite effect on liquid motion and entropy rate. Liquid flow has same impact for both porosity and velocity slip parameters. Larger thermal slip variable lead to decrease thermal distribution while reverse impact holds for heat source. Concentration has opposite trend through both random and thermophoresis parameters. An enhancement in thermal distribution and entropy rate are seen through variable thermal conductivity. An intensification in entropy rate has been noticed through concentration dependent conductivity variable. The considered configuration has relevance for detecting cooling towers, polymer extrusion, spinning of filaments, cable coating and metallurgical processes.

Chain-like Structures Facilitate Li+ Transport in Concentrated Aqueous Electrolytes: Insights from Ultrafast Infrared Spectroscopy and Molecular Dynamics Simulations.

Highly concentrated aqueous electrolytes have attracted attention due to their unique applications in lithium ion batteries (LIBs). However, the solvation structure and transport mechanism of Li+ cations at concentrated concentrations remain largely unexplored. To address this gap in knowledge, we employ ultrafast infrared spectroscopy and molecular dynamics (MD) simulations to reveal the dynamic and spatial structural heterogeneity in aqueous lithium chloride (LiCl) solutions. The coupling between the reorientation dynamics of the extrinsic probe and the macroscopic viscosity in aqueous LiCl solutions was analyzed using the Stokes-Einstein-Debye (SED) equations. MD simulations reveal that the Cl- and Li+ form chain-like structures through electrostatic interactions, supporting the vehicular migration of Li+ through the chain-like structure. The concentration dependent conductivity of the LiCl solution is well reproduced, where Li(H2O)2+ and Li(H2O)3+ are the dominant species that contribute to the conduction of Li+. This study is expected to establish correlations between ion pair structures and macroscopic properties.

Profiled Ion-Exchange Membranes for Reverse and Conventional Electrodialysis.

Profiled ion-exchange membranes are promising for improving the parameters of reverse electrodialysis due to the reduction of pumping power and electrical resistance. The smooth commercial heterogeneous cation-exchange MK-40 and anion-exchange MA-41 membranes were chosen as the initial membranes. Profiled membranes with three different types of surface profiles were obtained by hot pressing the initial membranes. The bilayer membranes were made on the basis of single-layer profiled membranes by casting MF-4SK film on the profiled surfaces. The diffusion permeability of all types of single-layer and bilayer profiled membranes was higher than of the initial ones due to the appearance of large defects on their surface during pressing. The conductivity of the profiled membrane was lower in the diluted solution and higher in the concentrated solution than of the initial one for all samples except for the bilayer anion-exchange membrane. The conductivity of that sample was lower than that of the initial anion-exchange MA-41 membrane over the entire range of studied concentrations. The counter-ion transport numbers for all studied membranes were calculated based on the concentration dependences of conductivity and diffusion permeability of the membrane by the microheterogeneous model. The selectivity of single layer and bilayer profiled membranes became lower after their profiling due to the increase of the solution phases of membranes. The asymmetry of the current-voltage curves for all single-layer and bilayer profiled membranes was found. The application of the single layer and bilayer profiled membranes in reverse electrodialysis did not lead to an increase in power density.

Effect of Pore Filling on Properties of Nanocomposites LiClO4-MIL-101(Cr) with High Ionic Conductivity.

Experimental data on nitrogen adsorption, pellets density and ionic conductivity of nanocomposite solid electrolytes (1−x)LiClO4–xMIL-101(Cr) were interpreted in frames of the model of the composite in which the lithium salt fills the pores of a metal-organic framework MIL-101(Cr). According to the model, the concentration of lithium salt located in the pores reaches a maximum at the concentration x = xmax which is defined by a ratio of the molar volume of LiClO4 and the total volume of accessible pores in the MIL-101(Cr) framework. The model allows one to describe the dependences of pore volume and pellet density on the concentration of MIL-101(Cr). Conductivity of the composites were successfully described by two separate mixing equations for concentration ranges x < xmax and x > xmax. In the first concentration region x < xmax, the composite may be regarded as a mixture of LiClO4 and MIL-101(Cr) with completely filled pores accessible for LiClO4. At x > xmax, the total amount of lithium perchlorate is located in the pores of MIL-101(Cr) and occupies only part of the volume of the accessible pores. It was found that xmax value determined from the concentration dependence of conductivity (xmax = 0.06) is noticeably lower than the corresponding value estimated from adsorption data (xmax = 0.085) indicating a practically complete filling the pores of MIL-101(Cr) in the composite pellets heated before conductivity measurements.

Lithium-Cation Conductivity of Solid Solutions in Li6-xZr2-xAxO7 (A = Nb, Ta) Systems.

Li6-xZr2-xAxO7 (A = Nb; Ta) system with 0 < x < 0.30 is synthesized by glycine-nitrate method. Boundaries of solid solutions based on monoclinic Li6Zr2O7 are determined; temperature (200–600 °C) and concentration dependences of conductivity are investigated. It is shown that monoclinic Li6Zr2O7 exhibits better transport properties compared to its triclinic modification. Li5.8Zr1.8Nb(Ta)0.2O7 solid solutions have a higher lithium-cation conductivity at 300 °C compared to solid electrolytes based on other lithium zirconates due the “open” structure of monoclinic Li6Zr2O7 and a high solubility of the doping cations.

Preparation and characterization of carbon fibre powder (CFP)-polyvinyl alcohol (PVA) composite films showing percolation threshold behaviour

Carbon based polymer composites are important because of their probable electronic and biomedical applications. In the present work, we have prepared a composite of nano-size carbon fibre powder (CFP) with polyvinyl alcohol (PVA), hereafter referred to as CFP-PVA composite. Thin films of CFP-PVA composites have been prepared by solution casting method with different CFP concentrations (0.0–16 wt% or volume fraction f ∼ 0.0–9.15%). X-Ray diffraction (XRD) of the composites indicated enhanced crystallinity which influenced the electrical, dielectric, mechanical and thermal properties of the composite films. CFP filler concentration dependent conductivity and dielectric permittivity of the CFP-PVA composites showed interesting anomalous behaviour around a critical CFP concentration of 4 wt% (or fc ∼ 2.36% volume fraction). The observed anomalous behaviour indicated percolation threshold behaviour. Significantly high dielectric permittivity of the composite with low dissipation factor (tanδ varying from ∼ 0.1–0.5, for different concentrations, at a fixed frequency of 1 kHz) was considered to be due to the formation of micro capacitors in the composite and charge ordering within these micro-capacitors, near the percolation threshold. Improved electrical conductivity, dielectric permittivity, mechanical and other properties indicated multifunctional behaviour of the conducting CFP-PVA composites. The probable electronic and other applications of the composites have also been discussed.

Transport Characteristics of CJMAED™ Homogeneous Anion Exchange Membranes in Sodium Chloride and Sodium Sulfate Solutions.

The interplay between the ion exchange capacity, water content and concentration dependences of conductivity, diffusion permeability, and counterion transport numbers (counterion permselectivity) of CJMA-3, CJMA-6 and CJMA-7 (Hefei Chemjoy Polymer Materials Co. Ltd., China) anion-exchange membranes (AEMs) is analyzed using the application of the microheterogeneous model to experimental data. The structure–properties relationship for these membranes is examined when they are bathed by NaCl and Na2SO4 solutions. These results are compared with the characteristics of the well-studied homogenous Neosepta AMX (ASTOM Corporation, Japan) and heterogeneous AMH-PES (Mega a.s., Czech Republic) anion-exchange membranes. It is found that the CJMA-6 membrane has the highest counterion permselectivity (chlorides, sulfates) among the CJMAED series membranes, very close to that of the AMX membrane. The CJMA-3 membrane has the transport characteristics close to the AMH-PES membrane. The CJMA-7 membrane has the lowest exchange capacity and the highest volume fraction of the intergel spaces filled with an equilibrium electroneutral solution. These properties predetermine the lowest counterion transport number in CJMA-7 among other investigated AEMs, which nevertheless does not fall below 0.87 even in 1.0 eq L−1 solutions of NaCl or Na2SO4. One of the reasons for the decrease in the permselectivity of CJMAED membranes is the extended macropores, which are localized at the ion-exchange material/reinforcing cloth boundaries. In relatively concentrated solutions, the electric current prefers to pass through these well-conductive but nonselective macropores rather than the highly selective but low-conductive elements of the gel phase. It is shown that the counterion permselectivity of the CJMA-7 membrane can be significantly improved by coating its surface with a dense homogeneous ion-exchange film.

Инверсия проводимости в твердых растворах CdSexTe1-x

The results of electrical studies of CdSeхTe1-х solid solutions synthesized using the zone of additional heating of the vapor phase are presented. It is established that solid solutions are dishonorable systems. It was found that CdSeхTe1-х solid solutions are characterized by: high resistivity (at T = 298 K up to 109 Ohm∙cm), which increases with tellurium content. It was found that a high value of activation energy (up to 0.64 eV), monotonously decreasing with temperature; an abnormally long time to establish equilibrium after a sharp change in temperature; low Hall mobility (at T = 413 K no more than 100 cm2V-1s-1). It is established that the solid solutions are systems with a high degree of compensation and an inhomogeneous potential relief of the bands due to disordering of the structure. The disordering of the structure in CdSeхTe1-х solid solutions is due to the difference in ionic radii. The ionic radius of cadmium is small (1.03Å), and the ionic radius of tellurium is large (2.21Å). Such systems are characterized by the Frenkel type of natural disorder. An increase in the tellurium content in them promotes the formation of cadmium VCd vacancies with acceptor properties, which at high concentrations lead to an inversion of the type of conductivity from electron to hole. Temperature and concentration dependences of conductivity and Hall mobility are given.

Electrical Conductivity of Low-Temperature Potassium Cryolite Electrolytes Suitable for Innovation of Aluminum Preparation

Innovations of aluminum electrolysis process are focused on the inert electrodes and the new types of electrolytes with lower temperature of primary crystallization. The main component in new types of molten systems can be a potassium cryolite. Advantages of these electrolytes are low possible working temperature (above 660°C) and sufficient solubility of an electrochemical active compound (alumina) at these temperatures. The electrical conductivity is one of the most important properties of the electrolytes. Electrochemical impedance spectroscopy was used as a suitable measurement method for determination of the electrical conductivity. Potassium cryolite-based mixtures with the different molar ratios (molar ratio of KF and AlF3) and with various additives were studied as a function of the temperature. The molar ratio of binary melt KF-AlF3 varied from 1.2 to 1.5 with the step of 0.1. The temperature dependence (from 655°C to 850°C) and the influence of the addition of Al2O3, CaF2, MgF2 and LiF on the electrical conductivity were obtained. The electrical conductivity was measured by tube-type cell with stationary electrodes; AC-techniques with a sine wave signal in the high frequency range were applied. Temperature and concentration dependencies of conductivity in the studied systems were described by non-linear regression equation.

Insights into Charge-Redistribution in Double Layer Capacitors

Charge-redistribution (CR) in electrochemical double layer capacitors (EDLCs) manifests as voltage drop during open-circuit relaxation (OCR) after galvanostatic (GS) charging, and voltage recovery during OCR after GS discharging. The complex porous structure of electrodes causes a capacitor to charge/discharge non-uniformly which causes charge-redistribution in OCR. In this work, we have used a macro-homogeneous transport model which incorporates electrolyte concentration dependent conductivity and constant capacitance to analyze CR. The model makes a new prediction that CR occurs over two time scales, a short one, of a couple of seconds, driven by potential gradient across an electrode at the termination of the preceding galvanostatic operation, and a long one, of hundreds of seconds, driven by electrolyte concentration gradients inside and outside pores. The extent of CR at two electrodes differs dramatically. The model also modifies other predictions of constant conductivity based models developed earlier in view of depletion/accumulation of electrolyte in pores. The linear variation of cell potential with log(t), used as a test of self-discharge due to faradaic reaction, is predicted by our transport models for CR itself. The scaling is different for short and long time CR, and sensitively depends on electrolyte conductivity in pores.

Temperature Coefficients of Electrical Conductivity and Conduction Mechanisms in Butyl Rubber-Carbon Black Composites

Electrical properties of butyl rubber filled with General Purpose Furnace (GPF) carbon black were studied. The carbon black concentration (X) in the compound was X = 40, 60, 70, 80, and 100 parts by weight per hundred parts by weight of rubber (phr). The corresponding volume fractions of GPF carbon black were 0.447 ± 0.022, 0.548 ± 0.027, 0.586 ± 0.029, 0.618 ± 0.031 and 0.669 ± 0.034, respectively. The concentration dependence of conductivity ( $$ \sigma $$ ) at constant temperature showed that $$ \sigma $$ follows a percolation theory; $$ \sigma \propto \left( {X - X_{o} } \right)^{\gamma } $$ , where X o is the concentration at percolation threshold. The exponent $$ \gamma $$ was found as 6.6 (at room temperature 30°C). This value agrees with other experimental values obtained by many authors for different rubber-carbon black systems. Electron tunneling between the aggregates, which are dispersed in the insulator rubber, was mainly the conduction process proposed at constant temperature in the butyl-GPF carbon black composites. Temperature dependence of conductivity was investigated in the temperature range from 30°C up to 120°C. All samples exhibit negative temperature coefficients of conductivity (NTCC). The values obtained are − 0.130°C−1, − 0.019°C−1, − 0.0082°C−1, − 0.0094°C−1, and − 0.072°C−1 for carbon black concentrations of 40 phr, 60 phr, 70 phr, 80 phr, and 100 phr, respectively. The samples of concentrations 40 phr and 60 phr have also positive temperature coefficients of conductivity (PTCC) of values + 0.031 and + 0.013, respectively. Electrical conduction at different temperatures showed various mechanisms depending on the carbon black concentration and/or the interval of temperature. The hopping conduction mechanism was noticed at the lower temperature region while carrier thermal activation mechanisms were recorded at the higher temperature range.

Investigations on materials and ion transport properties of Zn2+ conducting nano-composite polymer electrolytes (NCPEs): [(90 PEO: 10 Zn(CF3SO3)2)+ x ZnO

Zn2+ conducting 2-phase Nano-Composite Polymer Electrolyte (NCPE) membranes: [(90PEO:10Zn(CF3SO3)2)+ x ZnO] have been hot-press synthesized. Solid Polymer Electrolyte (SPE) composition: [90PEO:10Zn(CF3SO3)2], identified earlier as highest conducting film with room temperature conductivity (σrt)∼ 1.09×10−6S/cm, has been used as Ist–phase host and ZnO (active) nano-particles as IInd–phase dispersoid. Filler particle concentration dependent conductivity measurement revealed Optimum Conducting Composition (OCC): [(90PEO:10Zn(CF3SO3)2)+5 ZnO] with σrt∼ 1.84×10−5S/cm. Dispersal of filler results σ-enhancement of one order. Materials property of NCPE OCC has been studied by SEM, XRD, FTIR and thermal property by DSC/TGA. Ion transport property i.e. ionic conductivity (s) and total ionic (tion)/cation (t+) transport number have been measured using different ac/dc techniques. Temperature dependent s-measurement has been done to compute activation energy (Ea) by least square linear fitting of ‘log σ - 1/T’Arrhenius plot. All-Solid-State battery has been fabricated to study cell performance under varying load conditions.

Heterogeneous doping of sulfide-conducting phases based on calcium and barium thiolanthanates

The chemical method of preparation of oxide precursors was used to obtain sulfide-conducting ionic salts of CaY2S4, BaSm2S4 and heterogeneous additives of ZrS2 and SiS2, accordingly. The sintering modes for obtaining the heterogeneous systems of CaY2S4–ZrS2 and BaSm2S4–SiS2 were chosen. Samples were characterized using the methods of X-ray phase analysis and microprobe analysis. The methods of thermogravimetric and differential thermal analysis were used to determine thermal stability of samples. The temperature and concentration dependences of conductivity and average ionic transport numbers were studied. The range of compositions of heterogeneous mixtures is determined in which conductivity considerably exceeds conductivity of the basic sulfide-conducting solid electrolytes.

Synthesis and characterization of ion transport behavior in Cu2+-conducting nano composite polymer electrolyte membranes

Synthesis and characterization of ion transport behavior in Cu2+-conducting nano composite polymer electrolyte (NCPE) films: [90PEO: 10Cu(CF3SO3)2] + x CuO have been reported. NCPE films have been formed by hot-press casting technique using solid polymer electrolyte (SPE) film composition: [90PEO: 10Cu(CF3SO3)2] as 1st-phase host and nanoparticles of CuO in varying wt.(%) as 2nd-phase active filler. SPE: [90PEO: 10Cu(CF3SO3)2] was identified earlier as highest conducting film with room temperature conductivity (σrt) ~ 3.0 x 10−6 S cm−1, which is three orders of magnitude higher than that of pure polymer host PEO with σrt ~ 3.2 × 10−9 S cm−1. Filler particle concentration dependent conductivity study revealed NCPE film: [90PEO: 10Cu(CF3SO3)2] + 3%CuO as optimum conducting composition (OCC) exhibiting σrt ~ 1.14 × 10−5 S cm−1. Hence, by the fractional dispersal of 2nd-phase active filler into 1st-phase SPE host, σ-enhancement of approximately an order of magnitude has further been obtained. Ion transport behavior in NCPE OCC film has been characterized in terms of basic ionic parameters viz. ionic conductivity (σ), total ionic transference (tion)/cationic (t+) numbers. Temperature dependent conductivity measurement has also been done to explain the mechanism of ion transport and to compute activation energy (Ea). Materials characterization and hence, confirmation of complexation of salt in polymeric host and/or dispersal of filler particles in SPE host have been done by scanning electron microscopy (SEM), energy dispersive x-ray spectrometer (EDS), x-ray diffraction (XRD), Fourier transform infra-red (FTIR), differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). All-solid-state battery in the cell configuration: Cu (Anode) || SPE host/NCPE OCC film || C + I2 + Electrolyte) (Cathode) has been fabricated and cell performance has been studied under two load resistances viz. 60 and 100 kΩ. Each NCPE cell gave on an open circuit voltage (OCV) ~ 0.68 V. Some important battery parameters have also been evaluated from the plateau regions of cell potential discharge profiles.

Conductivity enhancement in K+-ion conducting dry Solid Polymer Electrolyte (SPE): [PEO: KNO3]: A consequence of KI dispersal and nano-ionic effect

Flexible films of dry Solid Polymer Electrolytes (SPEs): [PEO: KNO3] in varying salt concentrations have been hot-press cast. Salt concentration dependent conductivity study revealed two SPE films: [95PEO: 5KNO3] and [70PEO: 30KNO3] exhibiting relatively higher room temperature conductivity (σrt) ∼ 2.76 × 10−7 S/cm and ∼4.31 × 10−7 S/cm respectively. In order to increase σrt further, two strategies have been adopted. Firstly, fractional amount of KI has been dispersed as IInd-phase active filler into above two SPE film compositions which acted as Ist-phase host and Composite Polymer Electrolyte (CPE) films were hot-press cast. Filler particle concentration dependent conductivity study identified CPE films: [(95PEO: 5KNO3) + 7KI] and [(70PEO: 30KNO3) + 10 KI] as optimum conducting films with σrt ∼ 6.15 × 10−6 S/cm and ∼3.98 × 10−6 S/cm respectively. σrt-enhancement of approximately an order of magnitude was achieved by this approach. In second approach, dry powder mixture of (KNO3 + KI), in ratio that of above two CPE films, were subjected to high energy ball-milling separately for different durations prior to casting the films again. The conductivity measurements as a function of milling time identified CPE films: [(95PEO: 5KNO3) + 7KI] and [(70PEO: 30KNO3) + 10 KI] in which two respective (KNO3 + KI) ratios milled for 4- and 6-h, exhibited almost similar value of σrt ∼ 2.09 × 10−5 S/cm. This approach increased σrt further by ∼3–6 fold. The reason attributed for this has been Nano–ionic effect introduced at the interphase boundaries between KNO3 and KI, as a consequence of milling. These films have been referred to as milled CPE films. Subsequently, all the optimum conducting SPE and CPE (unmilled/milled) films were subjected to various characterization studies in order to evaluate their utility in potential All–Solid–State batteries. Ion transport behaviour has been characterized in terms of ionic conductivity (σ), total ionic (tion) and cation (t+) transference numbers, evaluated using different ac/dc techniques. Temperature dependent conductivity measurements have also been done to compute activation energy (Ea) value by linear least square fitting of respective ‘log σ −1/T’ plots. Materials characterization vis-a-vis complexation of salt in polymeric host has been confirmed by SEM/XRD/FTIR/DSC analysis.

Characterization of ion transport property in hot-press cast solid polymer electrolyte (SPE) films: [PEO: Zn(CF3SO3)2

Characterization of ion transport property in dry solid polymer electrolyte (SPE) films: [PEO: Zn(CF3SO3)2] in different salt wt% ratio has been reported. SPE films have been prepared by a hot-press casting procedure. Salt concentration dependent conductivity study at room temperature identified SPE film: [90PEO: 10 Zn(CF3SO3)2] as optimum conducting composition (OCC) with σ rt ~ 1.09 × 10−6 S/cm which is approximately three orders of magnitude higher than that of pure PEO host (σ rt ~ 3.20 × 10−9 S/cm). The reason attributed for σ rt enhancement has been the increase in degree of amorphous phase in polymeric host after salt complexation. This has been confirmed by X-ray diffraction (XRD), Fourier transform infrared (FTIR), differential scanning calorimetry (DSC), and polarized optical microscopy (POM) analysis. To evaluate the usefulness of SPE OCC film in all-solid-state-battery applications, ion transport property has been characterized in terms of basic ionic parameters viz. ionic conductivity (σ) and total ionic (t ion)/cation (t +) transport numbers. Mechanism of ion transport has been explained by temperature dependent conductivity measurements and the activation energy (E a) has been computed by least square linear fitting of “log σ − 1/T” Arrhenius plot.

Molecular modelling on solutions of 1-1′-spirobipirrolidinium tetrafluoroborate in acetonitrile

The results of molecular dynamics simulation on highly concentrated solutions of 1-1′-spiropyrrolidiniumtetrafluoroborate (SBPBF4) in acetonitrile at the temperature 298K in NVT ensemble are presented. With this objective, a new force field for SBP+ cation was developed on the basis of quantum chemical calculations. It has been established that an existence of maxima on concentration dependences of conductivity is determined by the significant growth of the ion clusterization in corresponding solutions. By using quantum theory “Atom in Molecules” analysis, the significant role of weak hydrogen bonds between fluorine atoms of the anion and hydrogen atoms of the methyl and methylene groups of the cation has been established.

The Properties of Synthesized Graphene and Polychlorotrifluoroethylene – Graphene systems

The properties of composites based on polychlorotryfluoroene with graphene containing 5 % (wt.) obtained by electrochemical dispergasion of graphite electrodes were researched. It is shown that the conductivity of the initial graphene that is determined by the impedance spectroscopy method is caused by the mainly electronic component. The concentration dependence of conductivity at low frequencies and real and imaginary components of the complex dielectric permeability at a frequency of 9 GHz composites significantly changes in the concentration range of 0,25-1%, that is stimulated by the presence of percolation threshold with graphene content of 0,45 %. The critical indexes of the percolation theory were calculated for the system.