PEO Electrolyte Research Articles

Characterization and optimization of a printed, primary silver–zinc battery

The increasing deployment of ubiquitous electronic systems such as distributed sensor networks and RFID tags has resulted in a need for high energy microbatteries. Printed batteries are particularly interesting because of the potential for low material loss, low processing cost, and ease of integration into low-profile flexible electronic systems. We have developed a two-step printing technique to deposit an alkaline electrolyte for a printed silver–zinc battery. The fabricated batteries are characterized with galvanostatic measurements and electrochemical impedance spectroscopy using a three electrode setup with a zinc reference electrode. High silver utilization of 94 ± 3% and an areal energy density of 4.1 ± 0.3 mWh cm −2 are achieved with a 57:29:14 H 2O:KOH:PEO ( M v = 600,000) electrolyte at a C/2 discharge rate 1.8 mA cm −2.

Photovoltaic performance of solid-state solar cells based on ZnO nanosheets sensitized with low-cost metal-free organic dye

In this study, the fabrication of photoanode of dye-sensitized solar cell (DSSC) using two-dimensional ZnO nanosheets (ZnONSs) and low-cost metal-free photosensitizer, evans blue, and evaluation of its photovoltaic performance in the solid-state DSSC with TiO2 nanotubes (TNTs) modified poly(ethylene oxide) (PEO) polymer electrolyte is described. The ZnONSs are synthesized via hydrothermal method and are characterized by high resolution scanning electron microscopy (HR-SEM), diffuse reflectance spectroscopy (DRS), photoluminescence spectroscopy (PLS) and X-ray diffraction (XRD) analysis. The photovoltaic performance of the cells is evaluated under standard air mass 1.5 global simulated illumination (100 mW cm−2). The current–voltage (I–V) and photocurrent–time (I–T) curves proved effective collection of electrons in the solid-state DSSCs with the ZnONSs photoanode. The solar to electrical energy conversion efficiency of the ZnONSs based DSSC with TNTs modified PEO electrolyte is 0.12%, which is about 1.5 times higher than that of the ZnO nanoparticles based DSSC, due to fast electron diffusion within the nanosheets.

Effect of hot pressing on the ionic conductivity of the PEO/LiCF 3SO 3 based electrolyte membranes

PEO/LiCF 3SO 3 (LiTFS) /Ethylene carbonate (EC) polymer electrolyte membranes were prepared with a solution casting method followed by a hot pressing process. The effect of the hot pressing process on the in-plane conductivity of the PEO electrolyte membranes was evaluated using a four-electrode AC impedance method. The composition, morphology, and microstructure of the composite polymer electrolyte were characterized using scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and differential scanning calorimetry (DSC). The AC impedance measurement results indicate that the hot pressing process can increase the room temperature conductivity of the membranes 14 times to 1.7 × 10 − 3 S cm − 1 depending upon the duration of the hot pressing process. The SEM, FTIR, XRD, and DSC results indicate that the hot pressing process could increase the amorphous part of the polymer electrolyte membrane or convert large spherulite crystals into nano-sized crystals.

Ion–polymer and ion–ion interaction in PEO‐based polymer electrolytes having complexing salt LiClO4 and/or ionic liquid, [BMIM][PF6

AbstractIon–polymer and ion–ion association in polymer electrolyte films of PEO complexed with salt LiClO4, ionic liquid (1‐butyl‐3‐methylimidazolium hexafluorophosphate, BMIMPF6) and (LiClO4 + BMIMPF6) have been studied by laser Raman spectroscopy. The cations (Li+ and/or BMIM+) of the dopant salt/IL are shown to complex with the ether oxygen of the polymer backbone (i.e. COC bond of PEO). The polymer–cation complexation results in the appearance of an additional peak at ∼1131 cm−1 apart from the COC stretching vibrations of PEO at ∼1062 and 1141 cm−1. This peak due to polymer–cation complexation is relatively strong for LiClO4 than BMIMPF6, indicating stronger interaction for the former. In the PEO:LiClO4 and PEO:BMIMPF6 spectra, Raman peaks at 937 and 747 cm−1, respectively related to Li+· ClO and BMIM+· PF ‘contact ion pairs’, have also been observed as a result of ion–ion association. In the polymer electrolyte PEO:LiClO4 + BMIMPF6 which contained two different anions, viz. ClO and PF, an interesting observation of the formation of ‘cross contact ion pairs’ viz. Li+· PF and BMIM+· ClO is also reported. Copyright © 2011 John Wiley & Sons, Ltd.

Photovoltaic Performance of ZnO Nanosheets Solar Cell Sensitized with Beta-Substituted Porphyrin

The photoanode of dye-sensitized solar cell (DSSC) was fabricated using two-dimensional ZnO nanosheets (2D ZnO NSs) sensitized with beta-substituted porphyrins photosensitizer, and its photovoltaic performance in solid-state DSSC with TiO2nanotubes (TiO2TNs) modified poly (ethylene oxide) (PEO) polymer electrolyte was studied. The ZnO NSs were synthesized through hydrothermal method and were characterized through high-resolution scanning electron microscopy (HRSEM), diffused reflectance spectra (DRS), photoluminescence spectra (PL), and X-ray diffraction (XRD) analysis. The crystallinity of the polymer electrolytes was investigated using X-ray diffraction analysis. The photovoltaic performance of the beta-substituted porphyrins sensitized solar cells was evaluated under standard AM1.5G simulated illumination (100 mW cm−2). The efficiency of energy conversion from solar to electrical due to 2D ZnO NSs based DSSCs is 0.13%, which is about 1.6 times higher than that of the control DSSC using ZnO nanoparticles (ZnO NPs) as photoanode (0.08%), when TiO2NTs fillers modified PEO electrolyte was incorporated in the DSSCs. The current-voltage () and photocurrent-time () curves proved stable with effective collection of electrons, when the 2D ZnO nanostructured photoanode was introduced in the solid-state DSSC.

Improved Stability of Unsealed Quasi-Solid-State Dye-Sensitized Solar Cell Using Poly(3,4-Ethylenedioxythiophene) Film as Layer Electrolyte

Quasi-solid/solid polymer electrolytes have been the subject of extensive research for an alternative of liquid electrolyte for dye-sensitized solar cells (DSSCs) because of their advantages such as alleviated leakage, lower environmental impact and ease of device fabrication. In this work, the performance of the unsealed quasi-solid-state DSSCs based on composite poly (ethylene oxide) (PEO) electrolyte and N719 dye-sensitizer was examined on aging under atmospheric condition. The energy conversion efficiency of DSSC using the composite PEO electrolyte was 5.62 % under sun simulated light, AM 1.5 (100 mW cm-2) but gradually decreased to 0.95 % on aging for 90 days. An additional layer of poly(3,4-ethylenedioxythiophene) (PEDOT) electrolyte was incorporated with the composite polymer electrolyte for DSSC fabrication. The PEDOT layer was prepared by electrochemical polymerization of bis-ethylenedioxythiophene (bis-EDOT) and characterized by Raman spectroscopy and cyclic voltammetry. It was found that the energy conversion efficiency of DSSC based on the composite polymer electrolyte incorporated with PEDOT layer was 5.57 % and gradually decreased to 1.76 % under the same aging condition. Thus an additional layer of PEDOT electrolyte provided an improved stability of DSSC.

Effects of a Block Copolymer as Multifunctional Fillers on Ionic Conductivity, Mechanical Properties, and Dimensional Stability of Solid Polymer Electrolytes

Solid polymer electrolytes with high ionic conductivities, good mechanical properties, dimensional stability, and easy processability were obtained from poly(ethylene oxide)-block-polyethylene (PEO-b-PE)-loaded poly(ethylene oxide) (PEO)/lithium perchlorate (LiClO(4)). In this article, we reported that the ionic conductivity and mechanical properties were remarkably increased due to the addition of the PEO-b-PE compared to that of PEO/LiClO(4) electrolyte. Scanning electron microscope (SEM), optical micrograph, and X-ray diffraction (XRD) results indicate that the addition of the copolymer, PEO-b-PE, decreased the defects of the PEO electrolyte films. Good dimensional stability was observed by dynamic rheological techniques up to 100 °C (higher than the melting point of PEO, 65 °C). A bicontinuous phase structure, that is crystalline PE domains within a matrix of PEO/salt, was proposed as the mechanism for such comprehensive enhancements in the ionic conductivity, mechanical properties, and dimensional stability obtained simultaneously in this study through a facile approach based on incorporation of a copolymer.

Application of ionic liquid doped solid polymer electrolyte

The electrical, structural, and photoelectrochemical properties of the polymer electrolyte PEO:NaI/I2 doped with an ionic liquid 1-ethyl 3-methylimidazolium dicyanamide (EMImDCN) have been reported. Incorporation of the ionic liquid (IL) increases the membrane homogeneity, decreased surface roughness, and enhances the short current (J sc). Additionally, the doping of IL provides more charge carriers which enhances overall ionic conductivity (σ). The optimized σ was found at 40 wt.% IL composition. The fabricated DSSC using this new solid electrolyte showed 1.43% efficiency at 100 mW cm−2.

Combined effect of CuO nanofillers and DBP plasticizer on ionic conductivity enhancement in the solid polymer electrolyte PEO–LiCF3SO3

We report a new kind of polyethylene oxide, PEO–LiCF3SO3-based composite polymer electrolyte, containing active copper oxide (CuO) nanoparticles with dibutyl phthalate (DBP) prepared by solution-cast technique. The incorporation of 10 wt.% DBP and 5 wt.% CuO to the salted polymer showed a significant conductivity enhancement with maximum conductivity 2.62 × 10−4 Scm−1 at room temperature. This could be attributed to the increasing of amorphous phase content and structural changes in the polymer electrolyte. Arrhenius plot suggest that temperature-dependent conductivity is a thermally activated process.

Interfacial properties between LiFePO 4 and poly(ethylene oxide)–Li(CF 3SO 2) 2N polymer electrolyte

The interface resistance between Li x FePO 4 and poly(ethylene oxide) (PEO)–Li(CF 3SO 2) 2N (LiTFSI) was examined by AC impedance measurement of a Li x FePO 4/PEO–LiTFSI/Li x FePO 4 cell in the temperature range of 30–60 °C. Four types of resistance, R0, R1, R2 and R3 were proposed according to analysis of the cell impedance using an equivalent circuit. The sum of R0 and R1 in the high frequency range is consistent with the resistance of the PEO electrolyte. R2 in the middle frequency range is related to lithium ion transport to an active point for charge transfer inside the composite electrode, and R3 in the low frequency range is considered to be the charge transfer resistance. The activation energy for R2 was affected by the thickness and composition of the electrode, whereas that for R3 was not.

Influences of poly(ether urethane) introduction on poly(ethylene oxide) based polymer electrolyte for solvent-free dye-sensitized solar cells

Abstract A poly(ether urethane) (PEUR)/poly(ethylene oxide) (PEO)/SiO 2 based nanocomposite polymer is prepared and employed in the construction of high efficiency all-solid-state dye-sensitized nanocrystalline solar cells. The introduction of low-molecular weight PEUR prepolymer into PEO electrolyte has greatly enhance the electrolyte performance by both improving the interfacial contact properties of electrode/electrolyte and decreasing the PEO crystallization, which were confirmed by XRD and SEM characteristics. The effects of polymer composition, nano SiO 2 content on the ionic conductivity and I 3 − ions diffusion of polymer-blend electrolyte are investigated. The optimized composition yields an energy conversion efficiency of 3.71% under irradiation by white light (100 mW cm −2 ).

Crystallinity and order of poly(ethylene oxide)/lithium triflate complex confined in nanoporous membranes

The confinement of poly(ethylene oxide), PEO, electrolyte in pores of 13, 35, 55 and 100 nm in diameter in nanoporous alumina membranes was seen to have effects on the ionic conduction properties. Specific conductivity values for the PEO/lithium triflate complex in the 13 and 35 nm pores, for temperatures below the melt temperatures, were increased by a factor of four compared to the non-confined polymer and the 55 and 100 nm pore systems. Thermal analysis data indicate the melting temperature for the PEO electrolyte in the pores is directly proportional to the pore size such that as the pore size of confinement is decreased, the T m decreases as well. The same behavior is seen for the amount of crystallinity, with less crystallinity being observed as the pores become smaller. Perhaps the observed conduction behavior could be attributed to less crystallinity. However, it is known that confinement of polyethers in pores results in stretching and ordering of the backbone and that such ordering can increase ion conduction. This ordering would seem to be the major factor involved in these results. The enhanced conduction only being seen in the 13 and 35 nm pores and not the 55 and 100 nm pores is attributed to the larger size for the latter which allows a more bulk-like behavior with less ordering.

Investigation of the inherent electrical potential of PEO electrolyte films

Measurement of the through-plane potential of PEO–lithium triflate electrolyte films has demonstrated that they possess an inherent potential as cast from an acetonitrile solution onto a Teflon substrate. These films have an inherent potential of around 0.2 V and the cast films display a discharge behavior similar to a double layer capacitor system with a small discharge capacitance of 80 nF cm −2. It is postulated that electrochemical properties of the films can be attributed to different salt concentration at the two surfaces. This difference in concentration may result from a matching of the surface-free energy of the Teflon substrate side of the film and the side of the film where evaporation occurs with the lithium triflate species in the polymer. Different spherulite morphologies were also observed for each surface. These morphologies can be assigned to spherulites having much different ion concentrations. Attenuated total reflection (ATR) IR spectroscopy was used to investigate the surface concentrations of free ions, ion pairs and ion multiples of both surfaces of the films. AC impedance spectroscopy of the surfaces of the film was also conducted. These data indicated that there is a difference in the surface concentration of each side. The ability of electrolyte films to exhibit a potential as fabricated may have potential applications as an easily manufactured power source for micro and nanodevices.

Ion-conductivity and Young's modulus of the polymer electrolyte PEO–ammonium perchlorate

We present a study of impedance spectroscopy (IS) under varying loads. An equivalent circuit is proposed taking the deformability and the effect of change in free volume into account, which yields the dc ion-conductivity as well as the Young's modulus from these results. Independent measurements of elastic properties are done and the result is compared with Young's modulus predicted from IS. The sample we studied is PEO–NH 4ClO 4 with a salt fraction of 0.19 by weight, with frequencies varying in the range of 40 Hz to 3 MHz and loads varying from 400 to 1600 g.

Ionic noise measurement in polymer electrolytes

Electrical noise associated with ion transport (termed as “ionic noise”) has been measured at different temperatures, using a lock-in amplifier and dynamic signal analyzer for a polymer electrolyte PEO:NH4I and its CdS dispersed composite. The ionic noise suddenly increases as the polymer passes through its phase transition at T g and T m. The T g-peak in the noise measurement appears more clearly than what it does in DTA/DSC or conductivity measurements. Therefore, we suggest the noise technique as a good probe for studying phase transitions in ion conducting solid electrolytes. Further, the present noise measurements also confirm the known results of DTA/DSC studies that both T g and T m of polymer electrolytes shift on the formation of composites.

Polymer electrolyte with ionic liquid for DSSC application

AbstractWe have investigated the structural and ionic conductivity properties of the polymer electrolyte PEO:KI/I2 doped with an ionic liquid 1‐ethyl 3‐methylimidazolium thio‐cyanate (EMImSCN). Incorporation of the ionic liquid (IL) reduced the crystallinity, and enhanced the ionic conductivity. Optimized conductivity was found at 80 wt% of ionic liquid composition. This high electrical conductivity was suitable for dye sensitized solar cell (DSSC) application. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

Structural and ionic conductivity of PEO blend PEG solid polymer electrolyte

Structural and ionic conductivity of PEO blend PEG with KI solid polymer electrolyte system is presented. The polymer PEG showed miscible with the high molecular weight polymer PEO. The X-ray diffraction patterns of PEO/PEG with KI salt indicated the decrease in the degree of crystallinity with increasing concentration of the salt. The DSC measurements of PEO/PEG:KI polymer electrolyte system showed that the melting temperature is shifted towards the lower temperature with increase of the salt concentration. Optical micrographs demonstrated that the spherulites of different sizes are present along with dark regions between the spherulites for lower salt compositions. With increase of salt concentration more amorphous regions are observed. The significance of blend is the increase of one order in ionic conductivity when compared to without blend PEO electrolyte.

Thermal and electrical properties of solid polymer electrolyte PEO 9 Mg(ClO 4) 2 incorporating nano-porous Al 2O 3 filler

Solid polymer electrolyte PEO 9 Mg(ClO 4) 2 incorporating 10 wt.% nano-porous Al 2O 3 filler grains has been prepared by the solvent casting technique using acetonitrile as the common solvent. Al 2O 3 powder (activated acidic, Aldrich) with grain size 104 μm and pore size 5.8 nm were incorporated as an inert filler. Electrolyte films have been characterized by differential scanning calorimetry, complex impedance and dc polarization measurements. The nano-composite electrolyte as well as the filler-free electrolyte appear to be predominantly anionic conductors with ClO 4 − ions being the migrating species. The presence of the alumina filler has enhanced the ionic conductivity significantly. The conductivity enhancement has been attributed to Lewis acid–base type interactions between H groups at the filler grain surface and the ClO 4 − ions. Transient H-bonding through these interactions is expected to provide additional hopping sites and favourable conducting pathways for migrating ionic species.

A Hybrid Poly(ethylene oxide)/ Poly(vinylidene fluoride)/TiO2 Nanoparticle Solid‐State Redox Electrolyte for Dye‐Sensitized Nanocrystalline Solar Cells

AbstractHigh‐efficiency all‐solid‐state dye‐sensitized nanocrystalline solar cells have been fabricated using a poly(ethylene oxide)/poly(vinylidene fluoride) (PEO/PVDF)/TiO2‐nanoparticle polymer redox electrolyte, which yields an overall energy‐conversion efficiency of about 4.8 % under irradiation by white light (65.2 mW cm–2). The introduction of PVDF (which contains the highly electronegative element fluorine) and TiO2 nanoparticles into the PEO electrolyte increases the ionic conductivity (by about two orders of magnitude) and effectively reduces the recombination rate at the interface of the TiO2 and the solid‐state electrolyte, thus enhancing the performance of the solar cell.

Ionic conductivity of PEO 9: Cu(CF 3SO 3) 2: Al 2O 3 nano-composite solid polymer electrolyte

Cu ++ ion containing solid polymer electrolytes exhibit interesting electrochemical properties. In particular, the polymer electrolyte PEO 9:Cu(CF 3SO 3) 2 made by complexing copper triflate (CuTf 2) with PEO appears to show scientifically intriguing transport properties. Although some copper ion transport in these systems has been seen from plating stripping processes, the detailed mechanism of ionic transport and the species involved are yet to be established. In order to obtain enhanced ionic conductivities and also to contribute towards understanding the ionic transport process in Cu ++ ion containing, PEO based composite polymer electrolytes, we have studied the system PEO 9: CuTf 2: Al 2O 3 incorporating 10 wt.% of alumina filler particles of grain size 10 μm, 37 nm, 10–20 nm and also particles of pore size 5.8 nm. Thermal and electrical measurements show that the system remains amorphous down to room temperature. The composite electrolyte is predominantly an ionic conductor with electronic conductivity less than 2%. The triflate (CF 3SO 3 −) anions appear to be the dominant carriers. The presence of alumina grains has enhanced the conductivity significantly from room temperature up to 100 °C. The nano-porous grains with 5.8 nm pore size and 150 m 2/g specific surface area exhibited the maximum conductivity enhancement. This enhancement has been attributed to Lewis acid–base type surface interactions of ionic species with O 2− and OH − groups on the filler grain surface.