Conducting Polymer Electrolyte Films Research Articles

Experimental Investigations on Highly Conducting Solid Bio‐Polymer Electrolytes Based on Latex of Calotropis gigantea Plant

AbstractThe study has prepared highly conducting polymer electrolyte films using solution cast technique with poly(vinylidene fluoride‐co‐hexafluoropropylene) PVDF‐HFP, mixture of ethylene carbonate (EC), and propylene carbonate (PC) as plasticizer and latex of Calotropis gigantea (CGL) as an ionic source. In this study, four films are prepared using PVDF‐HFP:CGL in ratio 1:1 with the increasing concentration of EC+PC as 1, 2, 3, and 4 M named as 1:1:1, 1:1:2, 1:1:3, 1:1:4. The prepared polymer electrolyte is examined by polarized optical microscopy (POM), elemental dispersive X‐ray technique (EDX), and complex impedance spectroscopy. EDX and POM are studied for the surface morphology of all prepared samples and to investigate the porous nature of films. The enhancement in ionic conductivity occurs due to CGL and increasing amount of EC‐PC. Conductivity of highest composition (1:1:4) polymer electrolyte film is found to be ≈10−3 S cm−1. The optimized polymer electrolyte film is considered as a promising candidate for application in supercapacitors.

Ion Transport and Dielectric Studies on [PEO:TiO2]:NH4SCN Nanocomposite Polymer Electrolytes

AbstractAn improvement in ion transport behavior and dielectric properties of polyethylene oxide based polymer electrolytes have been investigated upon the dispersal of TiO2 nanoparticles. TiO2 nanoparticle is synthesized with the help of well‐known sol–gel technique. The different compositions of polymer electrolyte systems are prepared by the solution cast technique. Nanocomposite polymer electrolytes (NCPEs) films are synthesized by loading of nanoTiO2 particle in a pristine polymer electrolyte matrix. The structural and morphological behaviors of nanocomposite polymer electrolytes (NCPEs) have been subsequently characterized by XRD and SEM studies. The ionic behavior of synthesized NCPEs is ascertained by Wagner's polarization technique. AC and DC conductivity of polymer electrolyte films have been carried out using impedance spectroscopic techniques. Dielectric relaxation studies of polymer electrolytes are examined using impedance spectroscopic data. The conductivity relaxation mechanism of NCPEs has been concluded with the help of modulus formalism. DC conductivity of best ion‐conducting NCPEs at room temperature has been found to σ = 2.5 × 10−5 S cm−1. The electrode polarization effect has completely vanished in the dielectric and modulus formalism and the conductivity scaling data show a single master curve observed in ion dynamics. The change in ionic conductivity with frequency and temperature is studied by impedance spectroscopic investigations. The effect of salt on dielectric parameters of NCPEs is also extracted from impedance spectroscopic data to explore underlying ion dynamics.

Potassium Hydroxide Doped With (Poly(Methyl Methacrylate) (PMMA) Polymer as Electrolyte for Electrolytic Double layer Supercapacitor (EDLC) Application

The prime objective of the present paper is to develop polymer electrolyte doped with salt. A solution cast technique was adopted to develop a solid polymer electrolyte of polymer (Poly (methyl methacrylate) (PMMA) as host polymer and salt potassium hydroxide, KOH as dopant. Incorporation of salt increases the amophosity and homogeneity, decreases the surface roughness. Moreover, doping of salt (KOH) increases the overall conductivity of polymer electrolyte film. Electrochemical impedance spectroscopy (EIS) reveals the enhancement in conductivity (4 orders of magnitude) by salt doping. FTIR shows the complexation and composite nature of films. Polarized optical microscopy (POM) shows reduction in crystallinity which is further confirmed by Differential scanning calorimetry (DSC). Fabricated electrochemical double-layer supercapacitor using maximum conducting polymer salt electrolyte and symmetric carbon nanotubes electrodes shows specific capacitance of 21.86.
 Keywords: Polymer electrolyte; conductivity; DSC; FTIR

Synthesis and dielectric properties of PAN-based Na+ ion polymer electrolytes

Polymer electrolytes have become more prominent due to various important applications in electro-chemical appliances and other rechargeable cells. Polymer polyacrylonitrile (PAN) based sodium iodide (NaI) doped composite conducting polymer electrolyte was synthesized by solution cast method. The prepared conducting polymer electrolyte films were mechanically stable and transparent. Complexation of the composition, interaction between cation of salt and nitrogen of PAN and vibrational modes of ions was confirmed by Fourier transform infrared spectroscopic (FTIR) studies. The electrical conductivity and dielectric properties information was obtained by LCR meter through impedance study for the prepared electrolyte films. Dielectric constant, dielectric loss and AC conductivity were observed for PAN: NaI (90:10; 80:20; 70:30; 60:40) composition. The dielectric behavior was analyzed using ε1 and ε11 values. The ε1 and ε11 values are high at lesser frequencies and less at higher frequencies.

The D.C electrical properties of Lithium ion conducting solid polymer electrolyte based on polyvinyl alcohol

Lithium ion conducting polymer electrolyte films based on polyvinyl alcohol (PVA) with different concentration of lithium perchlorate salt, using a solution cast technique, have been prepared. The Solid polymer electrolyte (SPE) hasbeen characterized by XRD technique. The XRD analysis reveals the amorphous nature of the polymer electrolyte. Polymer sample of PVA with different concentration of lithium salt (0, 5, 10, 20) wt% with double distilled water as solvent have been prepared and studied. High conductivity of 1.85771X10-07 has been observed for the PVA with 20% LiClO4. The temperature dependent conductivity of polymer electrolyte follows the Arrhenius relationship which shows hopping of ion in the polymer system. The experiment result showed that the D.C electrical conductivity increased with increasing the lithium salt concentration.

Electrochemical double-layer supercapacitor using poly(methyl methacrylate) solid polymer electrolyte

The prime objective of the present article is to develop an efficient supercapacitor based on polymer electrolyte doped with salt. Solution cast technique was adopted to develop a solid polymer electrolyte of polymer poly(methyl methacrylate) (PMMA) as host polymer and salt potassium hydroxide (KOH) as a dopant. Incorporation of salt increases the amorphicity and assisted in conductivity enhancement. Moreover, doping of salt increases the overall conductivity of polymer electrolyte film. Electrochemical impedance spectroscopy reveals the enhancement in conductivity (four orders of magnitude) by salt doping. Fourier transform infrared shows the complexation and composite nature of films. Polarized optical microscopy shows the reduction in crystallinity, which is further confirmed by Differential scanning calorimetry. Fabricated electrochemical double-layer supercapacitor using maximum conducting polymer—salt electrolyte and symmetric carbon nanotubes electrodes shows specific capacitance of 21.86 F g−1.

Investigation on the Electrical Properties of Lithium Ion Conducting Polymer Electrolyte Films Based on Biodegradable Polymer Blends

In the present work, the polyvinyl alcohol/poly (N-vinyl pyrrolidone)/Lithium carbonate (PVA/PVP/Li2CO3) blend polymer electrolyte films were prepared via the solution casting technique, with varying concentration of Li2CO3 salt (0 to 25 wt%). The surface morphology of these blend electrolyte films was examined using polarized optical microscopy (POM). The electrical properties such as impedance (Z), quality factor (Q-factor) and phase angle () of PVA/PVP/Li2CO3 blend electrolyte films were elucidated using impedance analyzer in the frequencies from 50 Hz to 20 MHz and temperatures from 30 °C to 150 °C. It was observed that the inclusion of Li2CO3 salt into the PVA/PVP blend matrix led to an increase in the Z,  and Q-factor values. The maximum Z of 1.19 x 107 Ω (50 Hz, 30 °C) was observed for blend electrolyte film containing 25 wt% Li2CO3 salt. The  also increased from 139° (20 MHz, 90 °C) for PVA/PVP blend to 179° (20 MHz, 40 °C) for blend electrolyte film containing 25 wt% Li2CO3 salt. The Q-factor values was increased from 27.4 (10 MHz, 140 °C) for PVA/PVP blend to 56.2 (5 MHz,salt, 80 °C) for blend electrolyte film containing 25 wt% Li2CO3 salt.

Physical investigations on pure and KBr doped poly(vinyl alcohol) (PVA) polymer electrolyte films for solid state battery applications

Potassium ion conducting polymer electrolyte films were prepared based on poly(vinyl alcohol) (PVA) complexed with 5, 10 and 15 wt% potassium bromide (KBr) salt using solution-casting technique. X-ray diffraction and Fourier transform infrared spectroscopy studies were used to determine the complexation of the KBr salt with polymer structure. Differential scanning calorimetry was used to determine the melting temperatures and relative crystallinity values of pure PVA and PVA:KBr complexed films. The conductivity of the polymer films was measured using impedance spectroscopy. Room temperature ionic conductivity was found to be a maximum (1.23 × 10−5 S cm−1) for the (PVA:KBr) (85:15) complexed film, whose K+ ion transport number was found to be 0.97. Electrochemical cells were fabricated in the configuration K/(PVA:KBr)/(I2 + C + Electrolyte) and their discharge characteristics were studied under a constant load of 100 kΩ.

Thermal Analysis of 1-Ethyl-3-Methylimidazolium Trifluoromethanesulfonate Ionic Liquid to PEO-NaCF<sub>3</sub>SO<sub>3 </sub>Polymer Electrolyte

The objective of this study is to investigate the effect of ionic liquid to PEO-NaCF3SO3 solid polymer electrolyte. Sodium ion conducting polymer electrolyte films consisting of Polyethylene oxide (PEO) as a polymer host, Sodium trifluoromethanesulfonate (NaCF3SO3) as doping salt and 1-ethyl-3-methylimidazolium trifluoromethanesulfonate (EMiTF) as ionic liquid has been prepared by solution cast technique. Different amounts (5, 10, 15, 20, 25 and 30 wt. %) of EMiTF will be added to the optimized polymer-salt composition to develop PEO - NaCF3SO3 – EMiTF polymer electrolyte. Difference Scanning Calorimetry (DSC) and Thermogravimetric Analysis (TGA) indicated that the crystalline degree and the weight loss % of the electrolyte decrease with increasing the wt. % of the EMiTF respectively. The ionic transference number was found in the value of 0.95 which suggests that ions are the charge carriers.

Structural and Dielectric Properties of PVP Based Composite Polymer Electrolyte Thin Films

The study and application of thin film technology is entirely entered in to almost all the branches of science and technology. Transparent conducting oxide films have been widely used in the fields of flat panel displays, solar cells, touch panels and other optoelectronic devices owing to their high electrical conductivity and optical transmittance in visible region. In the present study, Solid state ion conducting polymer electrolyte films were prepared by doping nano-sized TiO2 particles on PVP (poly vinyl pyrrolidone) complexed with MgSO4·7H2O salt by solution casting technique and characterized by powder XRD, DSC, SEM, optical and dielectric studies. The XRD pattern of the prepared sample shows the semi-crystalline nature. SEM and EDS confirms the presence of compounds inside the material. Optical absorption studies are used to measure the bandgap of the prepared sample. Dielectric studies are performed to observe the conductivity of the sample.

A study of structural, electrical and electrochemical properties of PVdF-HFP gel polymer electrolyte films for magnesium ion battery applications

New magnesium ion conducting polymer electrolyte films are developed and their experimental investigations are reported. The polymer electrolyte films are composed of various poly(vinylidene fluoride-co-hexafluoropropylene):magnesium trifluoromethanesulfonate compositions (PVdF-HFP:Mg(Tf)2 in weight ratio) with different quantities of 1-ethyl-3-methylimidazolium trifluoromethanesulfonate ionic liquid (EMITf). X-ray diffraction reveals that the pristine PVdF-HFP polymer film possesses a semi-crystalline structure and its amorphicity increases with increasing Mg(Tf)2 and EMITf concentrations. From thermal analysis, the melting temperature (Tm), relative crystallinity (χc) and thermal stability of the 90PVdF-HFP:10Mg(Tf)2 gel polymer electrolyte film doped with 40wt.% EMITf are obtained as 112°C, 21.8% and 355°C, respectively. The room-temperature ionic conductivity of the gel polymer electrolyte film increases with increasing EMITf concentration and reaches a high value of approximately 4.63×10−3Scm−1 at 40wt.% EMITf due to its amorphicity increase and interconnected pore structure. For the 40wt.% EMITf electrolyte film, the temperature dependence of ionic conductivity follows the Arrhenius relation with an activation energy of 0.35eV. The electrochemical stability window of the 40wt.% EMITf electrolyte film is determined as ∼4.8V. The findings from this study are promising and have great potential for practical ionic device applications, particularly in rechargeable magnesium ion batteries.

Effect of EMIMBF4 ionic liquid addition on the structure and ionic conductivity of LiBF4-complexed PVdF-HFP polymer electrolyte films

New polymer electrolyte films of lithium tetrafluoroborate (LiBF4)-complexed poly(vinylidene fluoride-co-hexafluoropropylene) (PVdF-HFP) embedded with different quantities of 1-ethyl-3methylimidazolium tetrafluoroborate (EMIMBF4) ionic liquid were prepared by solution casting. The prepared films were characterized using various techniques: X-ray diffraction, scanning electron microscopy, impedance spectroscopy and electrochemical measurements. The pure PVdF-HFP possessed a semi-crystalline structure and its amorphicity increased with the addition of LiBF4 salt and EMIMBF4 ionic liquid. The size and interconnection of pores in the films were enhanced by EMIMBF4. Impedance measurements indicated that the room-temperature ionic conductivity of the films increased with increasing EMIMBF4 concentration until 15 wt.%, being up to 0.202 × 10−4 S cm−1, and then decreased with further increasing EMIMBF4 concentration. In addition, the temperature-dependent ionic conductivity of the polymer electrolyte films followed an Arrhenius relation and the 15 wt.% EMIMBF4-incorporated gel polymer electrolyte film exhibited a low activation energy for ionic conduction, being about 0.28 eV. Finally, the electrochemical stability window of the 85PVdF-HFP:15LiBF4+15 EMIMBF4 gel polymer electrolyte films was evaluated as approximately 4.4 V, which is a promising value for ion battery applications.

Electrical properties of biodegradable poly(ɛ-caprolactone): lithium thiocyanate complexed polymer electrolyte films

Lithium ion conducting polymer electrolyte films based on biodegradable poly(ɛ-caprolactone) (PCL) complexed with lithium thiocyanate (LiSCN) salt were prepared by solution cast technique. Thermal and electrical properties of the polymer electrolyte films were studied using differential scanning calorimetry (DSC) and ac impedance spectroscopy. In order to investigate the ion conduction mechanism and relaxation behavior of complex polymer electrolyte films, the conductivity, dielectric constant, loss tangent and electric modulus were analyzed as a function of frequency and temperature. The variation of conductivity with frequency obeyed the Johnscher's power law. The dielectric constant exhibited a higher value at a lower frequency and increased with rising temperature due to the polar nature of host polymer. The activation energies for both dc conductivity and relaxation had the same value (∼0.87 eV), implying that the charge carriers responsible for both conduction and relaxation were the same.

Lithium Ion Conducting Polymer Electrolyte Based on Poly (Vinyl Alcohol) – Poly (Vinyl Pyrrolidone) Blend with LiClO4

Li+ ion conducting polymer electrolyte films have been prepared based on Poly (Vinyl alcohol) - Poly (Vinyl pyrrolidone) blend with LiClO4 using a solution casting technique. The increase in the amorphous nature of the polymer electrolytes has been confirmed by XRD analysis. The complex formation between the polymer and the salt has been confirmed by FTIR analysis. The highest ionic conductivity has been found to be 8.64 × 10−6 Scm−1 at ambient temperature for 0.22 molecular weight percentage of LiClO4 doped Poly (Vinyl alcohol) - Poly (Vinyl pyrrolidone) blend with low activation energy (0.59 eV). The dielectric behavior has been analyzed using dielectric permittivity (ϵ′) of the samples.

Ionic Conductivity and Dielectric Properties of Plasticized Polyacrylonitrile Based Solid Polymer Electrolyte Films

The conducting polymer electrolyte films composed of polyacrylonitrile (PAN) as the host polymer, LiCF3SO3 and NaCF3SO3 as inorganic salts and ethylene carbonate (EC) as plasticizer were prepared by the solution cast technique. The conductivities of the films were characterized by impedance spectroscopy. On addition of more than 14 wt% of salt, the NaCF3SO3-containing PAN films exhibited higher ionic conductivity than the LiCF3SO3-containing PAN films. The values of the dielectric constant, εr and dielectric loss, εi increase as frequency decreases at room temperature. The temperature dependence of the conductivity obeys Arrhenius relation in the temperature range of 303 K to 353 K.

Preparation and characterization of PVP-based polymer electrolytes for solid-state battery applications

Sodium ion conducting polymer electrolyte films based on poly(vinyl pyrrolidone) (PVP) were prepared using solution casting technique. Structural characterization was performed using X-ray diffraction (XRD) technique. Increase in amorphous phase with the increase of dopant concentration was observed. Temperature dependence of electrical conductivity was performed using AC impedance analyzing technique in the frequency range of 0.1 KHz to 1 MHz. Activation energy values were evaluated, as well. Optical absorption studies were carried out in the wavelength range 200–600 nm. Absorption edge, direct band gap, and indirect band gap values were also evaluated. Optical absorption edge and optical band gap (both direct and indirect) showed decreasing trend with increasing the concentration of the dopant. Dominant conducting species in the present electrolyte system was determined using Wagner polarization technique and dominant conducting species were found to be ions rather than electrons. Solid-state batteries were developed using the present solid polymer electrolyte system and discharge characteristics over the load of 100 kΩ. Cell parameters, e.g., open circuit voltage, short circuit current, current density, power density were evaluated, too. Among these cells, the cell made up of PVP/NaI (70/30) ratio for electrolyte was found to be more stable than the other two cells PVP/NaI (90/10) and (80/20) ratios and the obtained results were comparable with the results achieved by other studies.

Effect of complexing salt on conductivity of PVC/PEO polymer blend electrolytes

Solid polymer electrolyte membrane comprising poly(vinyl chloride) (PVC), poly(ehylene oxide) (PEO) and different lithium salts (LiClO4, LiBF4 and LiCF3SO3) were prepared by the solution casting technique. The effect of complexing salt on the ionic conductivity of the PVC/PEO host polymer is discussed. Solid polymer electrolyte films were characterized by X-ray diffraction, FTIR spectroscopy, TG/DTA and ac impedance spectroscopic studies. The conductivity studies of these solid polymer electrolyte (SPE) films are carried out as a function of frequency at various temperatures ranging from 302 K to 353 K. The maximum room temperature ionic conductivity is found to be 0·079 × 10−4 S cm−1 for the film containing LiBF4 as the complexing salt. The temperature dependence of the conductivity of polymer electrolyte films seems to obey the Vogel-Tamman-Fulcher (VTF) relation.

Studies on electrical and dielectric properties of PVP:KBrO 4 complexed polymer electrolyte films

Potassium ion conducting polymer electrolytes based on polyvinyl pyrrolidone (PVP) complexed with different weight percent ratios of KBrO 4 salt were prepared by using solution cast technique. X-ray diffraction (XRD) and Fourier transform infrared (FT-IR) spectroscopy studies confirmed the complexation of the salt with the polymer. The glass transition temperature and relative percentage of crystallinity of these films were determined using differential scanning calorimetry (DSC). Dielectric measurements were made using ac impedance analyser in the frequency and temperature ranges 1 Hz–1 MHz and 303–373 K respectively. It was observed that the ionic conductivity increased with the increase of salt concentration as well as temperature. The temperature dependence of electrical conductivity of polymer electrolyte films followed Arrhenius relation. The variation of ac conductivity with frequency obeys Jonscher power law. The loss peak observed at 334 K in the dielectric loss spectra was identified as β relaxation. The modulus spectra indicated the non-Debye nature of the material.

A comparative study of lithium and sodium salts in PAN-based ion conducting polymer electrolytes

The conducting polymer electrolyte films consisting of polyacrylonitrile (PAN) as the host polymer, lithium triflate (LiCF3SO3) and sodium triflate (NaCF3SO3) as inorganic salts were prepared by the solution-cast technique. The pure PAN film was prepared as a reference. The ionic conductivity for the films is characterized using impedance spectroscopy. The room temperature conductivity for the PAN + 26 wt.% LiCF3SO3 film and the PAN + 24 wt.% NaCF3SO3 film is 3.04 × 10−4 S cm−1 and 7.13 × 10−4 S cm−1, respectively. XRD studies show that the complexation that has occurred in the PAN containing salt films and complexes formed are amorphous. The FTIR spectra results confirmed the complexation has taken place between the salt and the polymer. These results correspond with surface morphology images obtained from SEM analysis. The conductivity–temperature dependence of the highest conducting film from PAN + LiCF3SO3 and PAN + NaCF3SO3 systems follows Arrhenius equation in the temperature range of 303 to 353 K. The PAN containing 24 wt.% LiCF3SO3 film has a higher ionic conductivity and lower activation energy compared to the PAN containing 26 wt.%LiCF3SO3 film. These results can be explained based on the Lewis acidity of the alkali ions, i.e., the interaction between Li+ ion and the nitrogen atom of PAN is stronger than that of Na+ ion.

Electrical Conduction and Dielectric Relaxation Phenomena of PVA Based Polymer Electrolyte Films

Conducting polymer electrolyte (CPE) films based on poly(vinyl alcohol) (PVA) complexed with NaI salt were prepared by a solution cast technique. The structural properties of these electrolyte films were examined by XRD studies. The XRD results revealed that the amorphous domains of PVA polymer matrix were increased with the increase of NaI salt concentration. The glass transition temperature (T g ) of these systems was determined by DSC thermograms. Electrical conductivity was measured in the temperature range of 303-373 K and the conductivity was found to increase with the increase of dopant concentration, as well as temperature. The activation energy values were 0.478, 0.351, 0.319 and 0.284 eV for pure and 10%, 20% and 30% NaI complexed PVA films, respectively. The dielectric constant (ϵ′) was found to increase with the increase of temperature and decrease with the increase of frequency. Dielectric relaxation phenomenon was observed in the dielectric loss spectra and is attributed to the orientation of polar groups.