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Electrolyte Films (electrolyte + film)
Selected AbstractsCombustion synthesis of ceramic nanoparticles for solid oxide fuel cellsASIA-PACIFIC JOURNAL OF CHEMICAL ENGINEERING, Issue 4 2010Dehua Dong Abstract Two combustion synthesis methods involving the use of polyacrylamide hydrogel and humic acids (HAs) as fuels were developed to synthesize ceramic nanoparticles for fabrication of solid oxide fuel cells (SOFCs). Using polyacrylamide hydrogel as fuel, highly crystalline NiO/Ce0.8Sm0.2O1.9 (SDC) and SDC nanoparticles were synthesized to make a modified layer and subsequent dense electrolyte film on the anode support. HA was used as complexible fuel to synthesize Sm0.5Sr0.5CoO3 nanoparticles for preparing the SOFC porous cathode. The single SOFCs made from these nanoparticles exhibited a maximum power density of 740 mW cm,2 at 650 °C operated with H2/air as fuel/oxidant, suggesting the synthesized nanoparticles are of high quality as SOFC materials. Copyright © 2010 Curtin University of Technology and John Wiley & Sons, Ltd. [source] A Dual Electrochrome of Poly-(3,4-Ethylenedioxythiophene) Doped by N,N,-Bis(3-sulfonatopropyl)-4-4,-bipyridinium,Redox Chemistry and Electrochromism in Flexible DevicesCHEMSUSCHEM CHEMISTRY AND SUSTAINABILITY, ENERGY & MATERIALS, Issue 1 2010Shweta Bhandari Abstract An electrochromic zwitterionic viologen, N,N,-bis(3-sulfonatopropyl)-4-4,-bipyridinium, has been used for the first time for doping poly (3,4-ethylenedioxythiopene) (PEDOT) films during electropolymerization. Slow and fast diffusional rates for the monomer at deposition potentials of +1.2 and +1.8,V, respectively yielded the viologen-doped PEDOT films with granular morphology and with dendrite-like shapes. The dual electrochrome formed at +1.8,V, showed enhanced coloration efficiency, larger electrochemical charge storage capacity, and superior redox activity in comparison to its analogue grown at +1.2,V, thus demonstrating the role of dendritic shapes in amplifying electrochromism. Flexible electrochromic devices fabricated with the viologen-doped PEDOT film grown at +1.8,V and Prussian blue with an ionic liquid-based gel electrolyte film showed reversible coloration between pale and dark purple with maximum coloration efficiency of 187,cm2,C,1 at ,=693,nm. The diffusional impedance parameters and switching kinetics of the device showed the suitability of this dual electrochrome formed as a single layer for practical electrochromic cells. [source] Insulator Polarization Mechanisms in Polyelectrolyte-Gated Organic Field-Effect TransistorsADVANCED FUNCTIONAL MATERIALS, Issue 20 2009Oscar Larsson Abstract Electrolyte-gated organic field-effect transistors (OFETs) hold promise for robust printed electronics operating at low voltages. The polarization mechanism of thin solid electrolyte films, the gate insulator in such OFETs, is still unclear and appears to limit the transient current characteristics of the transistors. Here, the polarization response of a thin proton membrane, a poly(styrenesulfonic acid) film, is controlled by varying the relative humidity. The formation of the conducting transistor channel follows the polarization of the polyelectrolyte, such that the drain transient current characteristics versus the time are rationalized by three different polarization mechanisms: the dipolar relaxation at high frequencies, the ionic relaxation (migration) at intermediate frequencies, and the electric double-layer formation at the polyelectrolyte interfaces at low frequencies. The electric double layers of polyelectrolyte capacitors are formed in ,1,µs at humid conditions and an effective capacitance per area of 10,µF cm,2 is obtained at 1,MHz, thus suggesting that this class of OFETs might operate at up to 1,MHz at 1,V. [source] Effects of organophilic clay on the solvent-maintaining capability, dimensional stability, and electrochemical properties of gel poly(vinylidene fluoride) nanocomposite electrolytesJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 22 2002H. J. Liu Abstract Four quaternary alkyl ammonium salts were used in an organophilic procedure, performed on montmorillonite clay, and resulted in intercalation in dimethylformamide (DMF) or ethylene carbonate (EC)/propylene carbonate (PC) as a cosolvent between poly(vinylidene fluoride) (PVdF) and the organophilic clay. An examination using X-ray diffraction revealed that PVdF entered galleries of montmorillonite clay, and it exhibited exfoliation and intercalation phenomena when it was analyzed with transmission electron microscopy. Gel PVdF nanocomposite electrolyte materials were successfully prepared by the addition of the appropriate percentages of DMF or PC/EC as a cosolvent, organophilic clay, and lithium perchlorate to PVdF. The maximum ionic conductivity was 1.03 × 10,2 S/cm, and the materials exhibited better film formation, solvent-maintaining capability, and dimensional stability than electrolyte films without added organophilic clays. The results of cyclic voltammetry testing showed that the addition of the organophilic clays significantly enhanced the electrochemical stability of the polymer electrolyte system. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 3873,3882, 2002 [source] Structure, electrical and optical properties of (PVA/LiAsF6) polymer composite electrolyte filmsPOLYMER ENGINEERING & SCIENCE, Issue 5 2010Madhu Mohan Varishetty In this work, Li+ ion conducting polymer composite electrolyte films (PECs) were prepared based on poly (vinyl alcohol) (PVA), lithium hexafluoro arsenate (LiAsF6), and ceramic filler TiO2 using solution cast technique. The XRD and FTIR spectra were used to determine the complexation of the PVA polymer with LiAsF6 salt. The ionic conductivities of the (PVA + LiAsF6) and (PVA + LiAsF6 + TiO2) films have been determined by the A.C. impedance measurements in the temperature range 320,440 K. The maximum conductivity was found to be 5.10 × 10,4 S cm,1 for PVA:LiAsF6 (75:25) + 5 wt% TiO2 polymer composite film at 320 K. The calculation of Li+ ion transference number was carried out by the combination of A.C. impedance and D.C. polarization methods and is found to be 0.52 for PVA:LiAsF6 (75:25) + 5 wt% TiO2 film. Optical properties such as direct energy gap, indirect energy gap, and optical absorption edge values were investigated in pure PVA and salt complexed PVA films from their optical absorption spectra in the wavelength range of 200,600 nm. The absorption edge was found at 5.76 eV for undoped film, while it is observed at 4.87 and 4.70 eV for 20 and 25 wt% LiAsF6 doped films, respectively. The direct band gaps for these undoped and salt doped PVA films were found to be 5.40, 5.12, and 4.87 eV, respectively, whereas the indirect band gaps were determined as 4.75, 4.45, and 4.30 eV. POLYM. ENG. SCI., 2010. © 2009 Society of Plastics Engineers [source] Crystallinity, thermal properties, morphology and conductivity of quaternary plasticized PEO-based polymer electrolytesPOLYMER INTERNATIONAL, Issue 3 2007Yan-Jie Wang Abstract Quaternary plasticized solid polymer electrolyte (SPE) films composed of poly(ethylene oxide), LiClO4, Li1.3Al0.3Ti1.7(PO4)3, and either ethylene carbonate or propylene carbonate as plasticizer (over a range of 10,40 wt%) were prepared by a solution-cast technique. X-ray diffraction (XRD), differential scanning calorimetry (DSC), scanning electron microscopy (SEM) and electrochemical impedance spectroscopy (EIS) indicated that components such as LiClO4 and Li1.3Al0.3Ti1.7(PO4)3 and the plasticizers exerted important effects on the plasticized quaternary SPE systems. XRD analysis revealed the influence from each component on the crystalline phase. DSC results demonstrated the greater flexibility of the polymer chains, which favored ionic conduction. SEM examination revealed the smooth and homogeneous surface morphology of the plasticized polymer electrolyte films. EIS suggested that the temperature dependence of the films' ionic conductivity obeyed the Vogel,Tamman,Fulcher (VTF) relation, and that the segmental movement of the polymer chains was closely related to ionic conduction with increasing temperature. The pre-exponential factor and pseudo activation energy both increased with increasing plasticizer content and were maximized at 40 wt% plasticizer content. The charge transport in all polymer electrolyte films was predominantly reliant on lithium ions. All transference numbers were less than 0.5. Copyright © 2006 Society of Chemical Industry [source] | |||||||||||||