Li1.3Al0.3Ti1.7(PO4)3 filler effect on (PEO)LiClO4 solid polymer electrolyte

Composite polymer electrolyte (CPE) films consisting of PEO, LiClO₄, and Li_1.3Al_0.3Ti_1.7(PO₄)₃ with fixed EO/Li = 8 but different relative compositions of the two lithium salts were prepared by the solution casting method. The CPE films were characterized using SEM, DSC, electrical impedance spectroscopy (EIS), and ion transference number measurement. It was found that the incorporation of LiClO₄ and Li_1.3Al_0.3Ti_1.7(PO₄)₃ into PEO by keeping EO/Li = 8 reduced the crystallinity of PEO from 50.34% to the range of 3.57–15.63% depending upon the relative composition of the two salts. The room temperature impedance spectra of the CPE films all exhibited a shape of depressed semicircle in the high frequency range and inclined line in the low frequency range, but the high temperature ones were mainly inclined lines. The Li⁺ ionic conductivity of the CPE films mildly increased and then decreased with increasing Li_1.3Al_0.3Ti_1.7(PO₄)₃ content, and the maximum conductivities were obtained at Li_1.3Al_0.3Ti_1.7(PO₄)₃ content of 15 wt % for all measuring temperatures, for example, 1.378 × 10^?3 S/cm at 100 °C and 1.387 × 10^?5 S/cm at 25 °C. The temperature dependence of the ionic conductivity of the CPE films follows the Vogel–Tamman–Fulcher (VTF) equation The pseudo activation energies (E_a) were rather low, 0.053–0.062 eV, indicating an easy migration of Li⁺ in the amorphous phase dominant PEO. The pre‐exponent constant A and ion transference number t_Li+ were found to have a similar variation tendency with increasing Li_1.3Al_0.3Ti_1.7(PO₄)₃ content and reached their maximums also at Li_1.3Al_0.3Ti_1.7(PO₄)₃ content of 15 wt %. © 2005 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 43: 743–751, 2005     

Synthesis of anion conducting polymer electrolyte membranes by Pd-Catalyzed Buchwald-Hartwig Amination coupling reaction

A novel aryl bromine bearing polymer was synthesized by Friedel-Crafts polycondensation. This precursor polymer substrate was used for C–N coupling via Buchwald-Hartwig amination to incorporate 9 examples of aryl amines into the polymer chains with high conversions (80–100%). Two aminated polymers were subsequently quaternized to give anion conducting polymers. These quaternary ammonium polymers show promising electrochemical membrane property because of their ability to transport mobile anions through the material while being electrically insulating. Membrane characteristics crucial to high electrochemical performance including ion exchange capacity, anion conductivity, water uptake, swelling ratio, and alkaline stability were evaluated.     

The conducting polymer electrolyte based on polypyrrole-polyvinyl alcohol and its application in low-cost quasi-solid-state dye-sensitized solar cells

The effect of polypyrrole (PPy) on the polyvinyl alcohol (PVA)-potassium iodide (KI)-iodine (I₂) polymer electrolytes has been investigated and optimized to use in a dye-sensitized solar cell (DSSC). The different weight ratios of PVA: PPy (93: 2, 91: 4, 89: 6, 87: 8, and 85: 10 wt%) polymer electrolytes (PE) were prepared by solution casting. Structural, complex formation and surface roughness of the prepared electrolytes was confirmed by X-ray diffraction, FTIR, and atomic force microscopy (AFM) respectively. Conductivity plots of all polymer films showed increasing trend with temperature and concentration of PPy. The activation energy of the optimized system found to be 0.871 kJ mol^?1. UV-visible spectrum was adopted to characterize the absorption spectra of the material revealed that increase in the absorbance with increasing PPy content and shifting the absorbance maximum towards lower energy. The indirect band gap decreased from 3.78 to 2.14 eV and direct band gap decreased from 3.88 to 2.71 eV. The EIS analyses revealed the lower charge transfer resistance of 3.029 Ω cm² at the interface between CE and PE. The excellent performance was observed in the fabricated DSSCs using PVA (85%)/PPy (10%)/KI (5%)/I₂ polymer electrolyte with a short-circuit current density of 11.071 mA cm^?2, open-circuit voltage of 0.644 V, fill factor of 0.575, and photovoltaic conversion efficiency of 4.09% under the light intensity of 100 mW cm^?2. Hence, the PPy content in polymer electrolyte influences the remarkable performance of low-cost DSSC.     

Preparation and characterization of a new polymer electrolyte (PEO:NaClO3) for battery application

A new sodium-ion conducting thin-film polymer electrolyte based on the poly(ethylene oxide) (PEO) system has been prepared by a solution-casting method. Characterization by XRD, IR, and AC conductivity and Wagner's polarization were carried out on these thin-film electrolytes. From the transference number experiment it was found that the charge transport in these electrolytes is mainly due to ions. Conductivity studies show that the conductivity value of the PEO:NaClO₃ complex increases with the increase of salt concentration. An increase in the conductivity and a change in the cell parameters for the electrolyte system were found by the addition of the low molecular weight dimethylformamide or propylene carbonate as plasticizers. The cell parameters of these electrolyte systems were measured from a discharge study of the cell with the application of a load of 100 kΩ at room temperature in the common cell configuration Na|electrolyte|MnO₂. The open circuit voltage ranges from 2.02 V to 2.46 V and the short circuit current ranges from 570 μA to 1030 μA. Electronic Publication     

Polarizable continuum model study on the solvent effect of polymer matrix in poly(ethylene oxide)-based solid electrolyte

The Polarizable Continuum Model has been used to study the effect of polymer matrix on Li (+) and Mg (2+) complexation in poly(ethylene oxide)-based solid electrolyte. Structures of complexes, stabilization energies, and vibrational frequencies are compared with corresponding vacuum values. The solvent effect of the polymer decreases with increasing cation coordination number. Optimized complex geometries do not differ significantly compared to vacuum calculations. Calculated shifts in vibrational frequencies depend on the complex structure; for hexacoordinated ion most frequencies are slightly red-shifted. The most important effect is the decrease of differences between relative stabilities of different structures in the solvent.     

Photovoltage improvements and recombination suppression by montmorillonite addition to PEO gel electrolyte for dye-sensitized solar cells

Montmorillonite (MMT) added to electrolytes has been reported in the literature to facilitate the transport of I(-)/I(3)(-), and improve the ionic conductivity and consequent photocurrent of dye-sensitized solar cells (DSCs). This paper firstly observes, investigates and reports that MMT addition to a poly(ethylene oxide) (PEO)-based gel electrolyte not only improves the ionic conductivity of the gel electrolyte, but also increases the photovoltage and decreases the dark current. From the results of electrochemical impedance spectroscopy (EIS) and transient photovoltage spectra, we evidence that MMT in the polymer gel electrolyte can efficiently retard the charge recombination that occurs at the TiO(2)/dye/electrolyte interfaces.     

Quasi solid-state dye-sensitized solar cell with P(MMA-co-MAA)-based polymer electrolytes

Journal of Solid State Electrochemistry - A series of poly (methylacrylate-co-methylacrylic acid) (P(MMA-co-MAA)) gel polymer electrolytes containing iodide/triiodide (I−/I3−) redox...     

Protonic conducting organic/inorganic nanocomposites for polymer electrolyte membrane

Protonic conducting membrane can be used in many energy technological applications such as fuel cells, water electrolysis, hydrogen separation, sensors and other electrochemical devices. However, polymer electrolyte membrane usually lack thermal stability, resulting in narrow operational temperature windows. So, a new class of polymer membrane with high temperature stability and protonic conductivity is desired for many industrial applications. In this paper, new synthetic routes have been investigated for organic/inorganic nanocomposites hybrid polymer membranes of SiO₂/polymer (polyethylene oxides (PEO); polypropylene oxide (PPO); polytetramethylene oxide (PTMO)). Novel protonic conducting properties have also been investigated. The materials have been synthesized through sol–gel processes in flexible, ductile free-standing thin membrane form. The hybrid membrane has been found to be thermally stable up to 250°C and possess protonic conductivities of approximately 10⁻⁴ S/cm at temperature windows from room temperature to 160°C and relative humidity.     

Dye-sensitized solar cells based on composite solid polymer electrolytes

The ionic conductivity of polymer electrolytes and their interfacial contact with dye-attached TiO2 particles were enhanced markedly by the addition of amorphous oligomer into polymer electrolytes, resulting in very high overall energy conversion efficiency.     

A polymer electrolyte containing ionic liquid for possible applications in photoelectrochemical solar cells

Various iodide ion conducting polymer electrolytes have been studied as candidate materials for fabricating photoelectrochemical (PEC) solar cells and energy storage devices. In this study, enhanced ionic conductivity values were obtained for the ionic liquid tetrahexylammonium iodide containing polyethylene oxide (PEO)-based plasticized electrolytes. The analysis of thermal properties revealed the existence of two phases in the electrolyte, and the conductivity measurements showed a marked conductivity enhancement during the melting of the plasticizer-rich phase of the electrolyte. Annealed electrolyte samples showed better conductivity than nonannealed samples, revealing the existence of hysteresis. The optimum conductivity was shown for the electrolytes with PEO:salt = 100:15 mass ratio, and this sample exhibited the minimum glass transition temperature of 72.2 °C. For this optimum PEO to salt ratio, the conductivity of nonannealed electrolyte was 4.4 × 10⁻⁴ S cm⁻¹ and that of the annealed sample was 4.6 × 10⁻⁴ S cm⁻¹ at 30 °C. An all solid PEC solar cell was fabricated using this annealed electrolyte. The short circuit current density (I _SC), the open circuit voltage (V _OC), and the power conversion efficiency of the cell are 0.63 mA cm⁻², 0.76 V, and 0.47% under the irradiation of 600 W m⁻² light.     

Structural,thermal, vibrational,and electrochemical behavior of lithium ion conducting solid polymer electrolyte based on poly(vinyl alcohol)/poly(vinylidene fluoride) blend

The present study focuses on the preparation and characterization of poly(vinyl alcohol)/poly(vinylidene fluoride) blend polymer electrolyte doped with lithium triflate (LiCF₃SO₃). Interaction of lithium triflate with the host polymer in the solid polymer electrolyte was studied using X-ray diffraction, Fourier transform infrared spectroscopy and differential scanning calorimetry analysis. It was found that 15% salt doped polymer electrolyte possesses the highest ionic conductivity (2.7 × 10^–3 S/cm) at 303 K, the higher thermal stability at 175°C. Linear sweep voltammetry results revealed that the film is electrochemically stable up to 3.4 V.     

Magnesium ion transport in poly(ethylene oxide)-based polymer electrolyte containing plastic-crystalline succinonitrile

A new composition of magnesium (Mg)-ion-conducting polymer electrolyte comprising poly(ethylene oxide) (PEO) complexed with Mg trifluoromethanesulfonate (Mg triflate or Mg(Tf)₂) containing different amounts of a nonionic plastic crystal succinonitrile (SN) has been prepared and characterized. High polarity and rotational disorder of the SN molecules in the plastic-crystalline phase, supports the enhancement of ionic conductivity of the PEO-Mg(Tf)₂ complex system, showing a maximum room temperature ionic conductivity of ～6?×?10^-4 S cm^?1 observed with the addition of 50 wt.% of SN. X-ray diffraction, optical microscopy, and differential scanning calorimetry suggest a substantial structural modification, decrease in crystallinity, and various interactions in the polymer electrolyte components due to addition of SN. The cyclic voltammetry, impedance, and dc polarization studies confirm the Mg-ion conduction in the PEO complex. The electrochemical potential window of the electrolyte, observed from the linear sweep voltammetry, is determined to be ～4.1 V. The performance characteristics of the SN-incorporated polymer electrolyte system indicate their potential applicability as electrolytes in ionic devices including Mg batteries.     

Ionic conductivity enhancement in the solid polymer electrolyte PEO9LiTf by nanosilica filler from rice husk ash

Rice husk ash is a cheap raw material available in abundance in rice-growing countries. It contains around 85–90 % amorphous silica. Rice husk ash, when subjected to a simple chemical precipitation method, will produce nanosilica which can be used for many industrial and technological applications. In this work, we have successfully synthesized nano-sized silica from local rice husk ash and prepared the nanocomposite solid polymer electrolyte, PEO₉LiTf:SiO₂. The resulting electrolyte has been characterized by X-ray diffraction, differential scanning calorimetry, atomic force microscopy, Fourier transform infrared spectroscopy, and complex impedance spectroscopy. The electrolyte shows about a 12-fold increase in ionic conductivity at room temperature due to the silica filler. In the nanocomposite electrolyte, nanosilica particles obtained from rice husk ash behaved very similarly to the commercial grade nanosilica and had a size distribution in the 25- to 40-nm range. As already suggested by us and by others, the O^2? and OH^? surface groups in the filler surface interact with the Li⁺ ions and provide hopping sites for migrating Li⁺ ions through transient H bonding, creating additional high-conducting pathways. This would contribute to a substantial conductivity enhancement through increased ionic mobility. An additional contribution to conductivity enhancement, particularly at temperatures below 60 °C, appears to come from the increased fraction of the amorphous phase, as evidenced from the reduced crystallite melting temperature and the reduced enthalpy of melting due to the presence of the filler.     

PEO/PVDF-based gel polymer electrolyte by incorporating nano-TiO2 for electrochromic glass

Journal of Sol-Gel Science and Technology - To develop high performance mixed matrix gel polymer electrolyte, the synergistic effect of blending PVDF (PEO/PVDF weigh ratio of 85:15) and adding...     

Butyronitrile-based electrolyte for dye-sensitized solar cells

We elaborated a new electrolyte composition, based on butyronitrile solvent, that exhibits low volatility for use in dye-sensitized solar cells. The strong point of this new class of electrolyte is that it combines high efficiency and excellent stability properties, while having all the physical characteristics needed to pass the IEC 61646 stability test protocol. In this work, we also reveal a successful approach to control, in a sub-Nernstian way, the energetics of the distribution of the trap states without harming cell stability by means of incorporating NaI in the electrolyte, which shows good compatibility with butyronitrile. These excellent features, in conjunction with the recently developed thiophene-based C106 sensitizer, have enabled us to achieve a champion cell exhibiting 10.0% and even 10.2% power conversion efficiency (PCE) under 100 and 51.2 mW·cm(-2) incident solar radiation intensity, respectively. We reached >95% retention of PCE while displaying as high as 9.1% PCE after 1000 h of 100 mW·cm(-2) light-soaking exposure at 60 °C.     

Ionic liquid integrated polyethylene glycol (PEG)-based quasi-solid electrolyte for efficiency enhancement of dye-sensitized solar cell

Journal of Solid State Electrochemistry - We are presenting herein the effect of using three different cell electrolytes namely: (a) propylene carbonate containing 0.2 M LiI and...     

Sodium ion conducting nanocomposite polymer electrolyte membrane for sodium ion batteries

Journal of Solid State Electrochemistry - The paper reports effect of dispersion of titanium dioxide (TiO2) nanofiller on the sodium ion conducting nanocomposite polymer electrolyte membranes...     

High ionic conductivity P(VDF-TrFE)/PEO blended polymer electrolytes for solid electrochromic devices

Solid polymer electrolytes with excellent ionic conductivity (above 10(-4) S cm(-1)), which result in high optical modulation for solid electrochromic (EC) devices are presented. The combination of a polar host matrix poly(vinylidene fluoride-trifluoroethylene) P(VDF-TrFE) and a solid plasticized of a low molecular weight poly(ethylene oxide) (PEO) (M(w)≤ 20,000) blended polymer electrolyte serves to enhance both the dissolution of lithium salt and the ionic transport. Calorimetric measurement shows a reduced crystallization due to a better intermixing of the polymers with small molecular weight PEO. Vibrational spectroscopy identifies the presence of free ions and ion pairs in the electrolytes with PEO of M(w)≤ 8000. The ionic dissolution is improved using PEO as a plasticizer when compared to liquid propylene carbonate, evidently shown in the transference number analysis. Ionic transport follows the Arrhenius equation with a low activation energy (0.16-0.2 eV), leading to high ionic conductivities. Solid electrochromic devices fabricated with the blended P(VDF-TrFE)/PEO electrolytes and polyaniline show good spectroelectrochemical performance in the visible (300-800 nm) and near-infrared (0.9-2.4 μm) regions with a modulation up to 60% and fast switching speed of below 20 seconds. The successful introduction of the solid polymer electrolytes with its best harnessed qualities helps to expedite the application of various electrochemical devices.