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Polymer Electrolytes (polymer + electrolyte)
Kinds of Polymer Electrolytes Terms modified by Polymer Electrolytes Selected AbstractsHigh-Performance Alkaline Polymer Electrolyte for Fuel Cell ApplicationsADVANCED FUNCTIONAL MATERIALS, Issue 2 2010Jing Pan Abstract Although the proton exchange membrane fuel cell (PEMFC) has made great progress in recent decades, its commercialization has been hindered by a number of factors, among which is the total dependence on Pt-based catalysts. Alkaline polymer electrolyte fuel cells (APEFCs) have been increasingly recognized as a solution to overcome the dependence on noble metal catalysts. In principle, APEFCs combine the advantages of and alkaline fuel cell (AFC) and a PEMFC: there is no need for noble metal catalysts and they are free of carbonate precipitates that would break the waterproofing in the AFC cathode. However, the performance of most alkaline polyelectrolytes can still not fulfill the requirement of fuel cell operations. In the present work, detailed information about the synthesis and physicochemical properties of the quaternary ammonia polysulfone (QAPS), a high-performance alkaline polymer electrolyte that has been successfully applied in the authors' previous work to demonstrate an APEFC completely free from noble metal catalysts (S. Lu, J. Pan, A. Huang, L. Zhuang, J. Lu, Proc. Natl. Acad. Sci. USA2008, 105, 20611), is reported. Monitored by NMR analysis, the synthetic process of QAPS is seen to be simple and efficient. The chemical and thermal stability, as well as the mechanical strength of the synthetic QAPS membrane, are outstanding in comparison to commercial anion-exchange membranes. The ionic conductivity of QAPS at room temperature is measured to be on the order of 10,2,S cm,1. Such good mechanical and conducting performances can be attributed to the superior microstructure of the polyelectrolyte, which features interconnected ionic channels in tens of nanometers diameter, as revealed by HRTEM observations. The electrochemical behavior at the Pt/QAPS interface reveals the strong alkaline nature of this polyelectrolyte, and the preliminary fuel cell test verifies the feasibility of QAPS for fuel cell applications. [source] TiO2(B) Nanowires as an Improved Anode Material for Lithium-Ion Batteries Containing LiFePO4 or LiNi0.5Mn1.5O4 Cathodes and a Polymer Electrolyte,ADVANCED MATERIALS, Issue 19 2006G. Armstrong Rechargeable lithium-ion batteries have been constructed with a TiO2(B) nanowire anode, a gel electrolyte, and either a LiFePO4 or LiNi0.5Mn1.5O4 cathode. Cycling stability is very good as is rate capability (see figure), with 80% of the low-rate capacity being retained at C/5. [source] NMR Studies of Proton Transport in Anhydrous Polymer Electrolytes for High Temperature Fuel Cells,FUEL CELLS, Issue 3-4 2008H. A. Every Abstract This paper presents an NMR study of the dynamic processes related to proton transport in a new polymer consisting of two blocks , poly(2,6-diphenylphenol) (P3O) and an imidazole functionalised poly(2,6-dimethylphenol) (imi-PPE) , and subsequently doped with polyphosphoric acid (PPA). From 1H and 31P NMR relaxation and diffusion measurements of the individual homopolymers and block copolymer, it was observed that addition of PPA significantly enhanced the mobility of imi-PPE and the imi-block copolymer, but not of P3O. The similarity in 1H T2 values between imi-PPE and the imi-block copolymer suggests that the relaxation behaviour in the block copolymer is dominated by the imi-PPE phase. 1H diffusion in P3O and the imi-block copolymer were comparable to pure PPA, suggesting that the proton diffusion is similar in each case. For imi-PPE, the diffusion coefficients were several orders of magnitude lower, reflecting a restricted diffusion process that is not indicative of the proton mobility. For all three polymers, the 31P T2 relaxation behaviour and inability to measure 31P diffusion coefficients imply hindered translational motion of the phosphonate groups. From these results, it can be concluded that hydrogen bonds between the phosphoric acid and the polymer form a network that facilitates proton transport via a hopping mechanism. [source] Capacity Fading Mechanism in All Solid-State Lithium Polymer Secondary Batteries Using PEG-Borate/Aluminate Ester as Plasticizer for Polymer ElectrolytesADVANCED FUNCTIONAL MATERIALS, Issue 6 2009Fuminari Kaneko Abstract Solid-state lithium polymer secondary batteries (LPB) are fabricated with a two-electrode-type cell construction of Li|solid-state polymer electrolyte (SPE)|LiFePO4. Plasticizers of poly(ethylene glycol) (PEG)-borate ester (B-PEG) or PEG-aluminate ester (Al-PEG) are added into lithium-conducting SPEs in order to enhance their ionic conductivity, and lithium bis-trifluoromethansulfonimide (LiTFSI) is used as the lithium salt. An improvement of the electrochemical properties is observed upon addition of the plasticizers at an operation temperature of 60,°C. However, a decrease of discharge capacities abruptly follows after tens of stable cycles. To understand the origin of the capacity fading, electrochemical impedance techniques, ex-situ NMR and scanning electron microscopy (SEM)/energy dispersive X-ray spectroscopy (EDS) techniques are adopted. Alternating current (AC) impedance measurements indicate that the decrease of capacity retention in the LPB is related to a severe increase of the interfacial resistance between the SPE and cathode. In addition, the bulk resistance of the SPE film is observed to accompany the capacity decay. Ex situ NMR studies combined with AC impedance measurements reveal a decrease of Li salt concentration in the SPE film after cycling. Ex situ SEM/EDS observations show an increase of concentration of anions on the electrode surface after cycling. Accordingly, the anions may decompose on the cathode surface, which leads to a reduction of the cycle life of the LPB. The present study suggests that a choice of Li salt and an increase of transference number is crucial for the realization of lithium polymer batteries. [source] Solid Composite Polymer Electrolytes with High Cation Transference NumberISRAEL JOURNAL OF CHEMISTRY, Issue 3-4 2008Hadar Mazor This work presents the electrochemical and structural study of the dual modified composite LiBOB-based polymer electrolyte. Modification has been carried out by calix[6]pyrrole (CP) anion trap and nanosize silica filler. The main advantage of the use of LiBOB salt is the high ionic conductivity at near-ambient temperatures and low solid-electrolyte interphase (SEI) resistance. The conductivity of LiBOB:PEO20:CP0.125 with SiO2 is slightly lower than 10,5 Scm,1 at 30 °C, a value higher by about two orders of magnitude than that of the semi-crystalline LiCF3SO3 (LiTf)-PEO system. At 75 to 90 °C the bulk ionic conductivity of modified LiBOB polymer electrolyte approaches 1 mScm,1. The transference number of dual-modified LiBOB-polymer electrolyte is about 0.8 at 75 °C. Cyclic voltammetry tests showed a wide electrochemical stability window of the composite polymer electrolyte. The peak power of Li/MoOxSy cell with the polymer electrolyte film containing CP and SiO2 reaches 2.2 mW/cm2 and 3.0 mW/cm2 at 90 and 110 °C, respectively. [source] Physical and Electrochemical Properties of PVdF-HFP/SiO2 -Based Polymer Electrolytes Prepared Using Dimethyl Acetamide Solvent and Water Non-SolventMACROMOLECULAR CHEMISTRY AND PHYSICS, Issue 8 2007Kwang Man Kim Abstract Poly[(vinylidene fluoride)- co -hexafluoropropylene]/SiO2 polymer electrolytes were prepared by a phase inversion technique using DMAc solvent and water non-solvent. Cast film electrolytes filled with the same amount of SiO2 using DMAc were also made to compare physical and electrochemical properties. DMAc had a higher solubility to PVdF-based polymers than NMP, and DMAc produced highly porous structures with bigger cavities and influenced the reduction of crystallinity. Due to the highly porous nature of phase inversion membranes, the uptake of electrolyte solution reached more than 400% and room-temperature ionic conductivity was more than 10,3 S,·,cm,1. All of the liquid absorbed, however, did not necessarily contribute to increases in ionic conductivity. This was due to the different conduction modes of lithium cations in a complicated porous structure. Comprehensively optimizing all the properties measured, the phase inversion membrane electrolytes with 10,30 wt.-% SiO2 were the best candidates for use as the polymer electrolyte of lithium rechargeable batteries. [source] Polymer electrolyte using in situ quanternization for all solid-state dye-sensitized solar cellsPOLYMERS FOR ADVANCED TECHNOLOGIES, Issue 6 2009Wanchun Xiang Abstract Polymer electrolyte through in situ quanternization reaction by oligo-siloxane containing quanternary ammonium groups was synthesized for all solid-state dye-sensitized solar cells (DSSCs). These two latent crosslinked precursors are oligo-organosiloxane grafting oligo-ethylene oxide and propylene oxide dimethylamine (OEA) and the oligo-organosiloxane grafting oligo-ethylene oxide and propylene oxide bromide (OEB). This chemically crosslinked electrolyte shows good ambient conductivity of 2.6,×,10,4,S/cm when incorporating appropriate amount of 1-iodide oligo-ethylene glycol monomethylether (IOEGMME) as an additive. Photoelectrochemical performances for different electrolytes were also analyzed. Copyright © 2009 John Wiley & Sons, Ltd. [source] High-Performance Alkaline Polymer Electrolyte for Fuel Cell ApplicationsADVANCED FUNCTIONAL MATERIALS, Issue 2 2010Jing Pan Abstract Although the proton exchange membrane fuel cell (PEMFC) has made great progress in recent decades, its commercialization has been hindered by a number of factors, among which is the total dependence on Pt-based catalysts. Alkaline polymer electrolyte fuel cells (APEFCs) have been increasingly recognized as a solution to overcome the dependence on noble metal catalysts. In principle, APEFCs combine the advantages of and alkaline fuel cell (AFC) and a PEMFC: there is no need for noble metal catalysts and they are free of carbonate precipitates that would break the waterproofing in the AFC cathode. However, the performance of most alkaline polyelectrolytes can still not fulfill the requirement of fuel cell operations. In the present work, detailed information about the synthesis and physicochemical properties of the quaternary ammonia polysulfone (QAPS), a high-performance alkaline polymer electrolyte that has been successfully applied in the authors' previous work to demonstrate an APEFC completely free from noble metal catalysts (S. Lu, J. Pan, A. Huang, L. Zhuang, J. Lu, Proc. Natl. Acad. Sci. USA2008, 105, 20611), is reported. Monitored by NMR analysis, the synthetic process of QAPS is seen to be simple and efficient. The chemical and thermal stability, as well as the mechanical strength of the synthetic QAPS membrane, are outstanding in comparison to commercial anion-exchange membranes. The ionic conductivity of QAPS at room temperature is measured to be on the order of 10,2,S cm,1. Such good mechanical and conducting performances can be attributed to the superior microstructure of the polyelectrolyte, which features interconnected ionic channels in tens of nanometers diameter, as revealed by HRTEM observations. The electrochemical behavior at the Pt/QAPS interface reveals the strong alkaline nature of this polyelectrolyte, and the preliminary fuel cell test verifies the feasibility of QAPS for fuel cell applications. [source] Capacity Fading Mechanism in All Solid-State Lithium Polymer Secondary Batteries Using PEG-Borate/Aluminate Ester as Plasticizer for Polymer ElectrolytesADVANCED FUNCTIONAL MATERIALS, Issue 6 2009Fuminari Kaneko Abstract Solid-state lithium polymer secondary batteries (LPB) are fabricated with a two-electrode-type cell construction of Li|solid-state polymer electrolyte (SPE)|LiFePO4. Plasticizers of poly(ethylene glycol) (PEG)-borate ester (B-PEG) or PEG-aluminate ester (Al-PEG) are added into lithium-conducting SPEs in order to enhance their ionic conductivity, and lithium bis-trifluoromethansulfonimide (LiTFSI) is used as the lithium salt. An improvement of the electrochemical properties is observed upon addition of the plasticizers at an operation temperature of 60,°C. However, a decrease of discharge capacities abruptly follows after tens of stable cycles. To understand the origin of the capacity fading, electrochemical impedance techniques, ex-situ NMR and scanning electron microscopy (SEM)/energy dispersive X-ray spectroscopy (EDS) techniques are adopted. Alternating current (AC) impedance measurements indicate that the decrease of capacity retention in the LPB is related to a severe increase of the interfacial resistance between the SPE and cathode. In addition, the bulk resistance of the SPE film is observed to accompany the capacity decay. Ex situ NMR studies combined with AC impedance measurements reveal a decrease of Li salt concentration in the SPE film after cycling. Ex situ SEM/EDS observations show an increase of concentration of anions on the electrode surface after cycling. Accordingly, the anions may decompose on the cathode surface, which leads to a reduction of the cycle life of the LPB. The present study suggests that a choice of Li salt and an increase of transference number is crucial for the realization of lithium polymer batteries. [source] Polymer Electrolyte Membranes with a Pore-Filling Structure for a Direct Methanol Fuel Cell,ADVANCED MATERIALS, Issue 14 2003T. Yamaguchi Pore-filling membranes that are composed of a porous substrate and a filling polymer electrolyte have been developed. These polyelectrolyte membranes demonstrate low permeation with respect to methanol, high proton conductivity, good mechanical strength, chemical stability, and low cost, making them ideal for use in direct methanol fuel cells. The necessary characteristics can also be controlled by changing the substrate and the filling polymer electrolyte. [source] Solid Composite Polymer Electrolytes with High Cation Transference NumberISRAEL JOURNAL OF CHEMISTRY, Issue 3-4 2008Hadar Mazor This work presents the electrochemical and structural study of the dual modified composite LiBOB-based polymer electrolyte. Modification has been carried out by calix[6]pyrrole (CP) anion trap and nanosize silica filler. The main advantage of the use of LiBOB salt is the high ionic conductivity at near-ambient temperatures and low solid-electrolyte interphase (SEI) resistance. The conductivity of LiBOB:PEO20:CP0.125 with SiO2 is slightly lower than 10,5 Scm,1 at 30 °C, a value higher by about two orders of magnitude than that of the semi-crystalline LiCF3SO3 (LiTf)-PEO system. At 75 to 90 °C the bulk ionic conductivity of modified LiBOB polymer electrolyte approaches 1 mScm,1. The transference number of dual-modified LiBOB-polymer electrolyte is about 0.8 at 75 °C. Cyclic voltammetry tests showed a wide electrochemical stability window of the composite polymer electrolyte. The peak power of Li/MoOxSy cell with the polymer electrolyte film containing CP and SiO2 reaches 2.2 mW/cm2 and 3.0 mW/cm2 at 90 and 110 °C, respectively. [source] Fabrication and properties of crosslinked poly(propylene carbonate maleate) gel polymer electrolyte for lithium-ion batteryJOURNAL OF APPLIED POLYMER SCIENCE, Issue 4 2010Xiaoyuan Yu Abstract The poly(propylene carbonate maleate) (PPCMA) was synthesized by the terpolymerization of carbon dioxide, propylene oxide, and maleic anhydride. The PPCMA polymer can be readily crosslinked using dicumyl peroxide (DCP) as crosslinking agent and then actived by absorbing liquid electrolyte to fabricate a novel PPCMA gel polymer electrolyte for lithium-ion battery. The thermal performance, electrolyte uptake, swelling ratio, ionic conductivity, and lithium ion transference number of the crosslinked PPCMA were then investigated. The results show that the Tg and the thermal stability increase, but the absorbing and swelling rates decrease with increasing DCP amount. The ionic conductivity of the PPCMA gel polymer electrolyte firstly increases and then decreases with increasing DCP ratio. The ionic conductivity of the PPCMA gel polymer electrolyte with 1.2 wt % of DCP reaches the maximum value of 8.43 × 10,3 S cm,1 at room temperature and 1.42 × 10,2 S cm,1 at 50°C. The lithium ion transference number of PPCMA gel polymer electrolyte is 0.42. The charge/discharge tests of the Li/PPCMA GPE/LiNi1/3Co1/3Mn1/3O2 cell were evaluated at a current rate of 0.1C and in voltage range of 2.8,4.2 V at room temperature. The results show that the initial discharge capacity of Li/PPCMA GPE/LiNi1/3Co1/3Mn1/3 O2 cell is 115.3 mAh g,1. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010 [source] Novel amphiphilic polymer gel electrolytes based on (PEG- b -GMA)- co -MMAJOURNAL OF APPLIED POLYMER SCIENCE, Issue 3 2010Dan Luo Abstract Amphiphilic conetwork,structured copolymers containing different lengths of ethylene oxide (EO) chains as ionophilic units and methyl methacrylate (MMA) chains as ionophobic units were prepared by free radical copolymerization and characterized by FTIR and thermal analysis. Polymer gel electrolytes based on the copolymers complexed with liquid lithium electrolytes (dimethyl carbonate (DMC) : diethyl carbonate (DEC) : ethylene carbonate (EC) = 1 : 1 : 1 (W/W/W), LiPF6 1.0M) were characterized by differential scanning calorimetry and impedance spectroscopy. A maximum ion conductivity of 4.27 × 10,4 S/cm at 25oC was found for the polymer electrolyte based on (PEG2000- b -GMA)- co -MMA with long EO groups. Moreover, the effect of temperature on conductivity of the amphiphilic polymer electrolytes obeys the Arrhenius equation. The good room temperature conductivity of the polymer electrolytes is proposed to relate to the enhancement in the amorphous domain of the copolymers due to their amphiphilic conetwork structure. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010 [source] Poly(vinyl alcohol),polyacrylamide blends with cesium salts of heteropolyacid as a polymer electrolyte for direct methanol fuel cell applicationsJOURNAL OF APPLIED POLYMER SCIENCE, Issue 6 2010M. Helen Abstract A class of inorganic,organic hybrid membranes with low methanol permeability characteristics for possible direct methanol fuel cell (DMFC) applications was architected, formulated, and fabricated through the blending of poly(vinyl alcohol) (PVA) and polyacrylamide (PAM) followed by crosslinking with glutaraldehyde (Glu). Cesium salts of different heteropolyacids, including phosphomolybdic acid (PMA), phosphotungstic acid (PWA), and silicotungstic acid (SWA), were incorporated into the polymer network to form corresponding hybrid membrane materials, namely, PVA,PAM,CsPMA,Glu, PVA,PAM,CsPWA,Glu, and PVA,PAM,CsSWA,Glu, respectively (where "Cs" together with a heteropolyacid abbreviation indicates the cesium salt of that acid). All the three hybrid polymer membranes fabricated exhibited excellent swelling, thermal, oxidative, and additive stability properties with desired proton conductivities in the range 10,2 S/cm at 50% relative humidity. A dense network formation was achieved through the blending of PVA and PAM and by crosslinking with Glu, which led to an order of magnitude decrease in the methanol permeability compared to the state-of-the-art commercial Nafion 115 membrane. The hybrid membrane containing CsSWA exhibited a very low methanol permeability (1.4 × 10,8 cm2/s) compared to other membranes containing cesium salt of heteropolyacids such as PMA and PWA. The feasibility of these hybrid membranes as proton-conducting electrolytes in DMFC was investigated, and the preliminary results were compared with those of Nafion 115. The results illustrate the attractive features and suitability of the fabricated hybrid membranes as an electrolyte for DMFC applications. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010 [source] Proton transportation in an organic,inorganic hybrid polymer electrolyte based on a polysiloxane/poly(allylamine) networkJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 15 2005Ping-Lin Kuo Abstract A new class of proton-conducting polymer was developed via the sol,gel process from amino-containing organic,inorganic hybrids by the treatment of poly(allylamine) with 3-glycidoxypropyltrimethoxysilane doped with ortho -phosphoric acid. The polymer matrix contains many hydrophilic sites and consists of a double-crosslinked framework of polysiloxane and amine/epoxide. Differential scanning calorimetry results suggest that hydrogen bonding or electrostatic forces are present between H3PO4 and the amine nitrogen, resulting in an increase in the glass-transition temperature of the poly(allylamine) chain with an increasing P/N ratio. The 31P magic-angle spinning NMR spectra indicate that three types of phosphate species are involved in the proton conduction, and the motional freedom of H3PO4 is increased with increasing P/N ratios. The conductivity above 80 °C does not drop off but increases instead. Under a dry atmosphere, a high conductivity of 10,3 S/cm at temperatures up to 130 °C has been achieved. The maximum activation energy obtained at P/N = 0.5 suggests that a transition of proton-conducting behavior exits between Grotthus- and vehicle-type mechanisms. The dependence of conductivity on relative humidity (RH) above 50% is smaller for H3PO4 -doped membranes compared with H3PO4 -free ones. These hybrid polymers have characteristics of low water content (23 wt %) and high conductivity (10,2 S/cm at 95% RH), making them promising candidates as electrolytes for fuel cells. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 3359,3367, 2005 [source] Physical and Electrochemical Properties of PVdF-HFP/SiO2 -Based Polymer Electrolytes Prepared Using Dimethyl Acetamide Solvent and Water Non-SolventMACROMOLECULAR CHEMISTRY AND PHYSICS, Issue 8 2007Kwang Man Kim Abstract Poly[(vinylidene fluoride)- co -hexafluoropropylene]/SiO2 polymer electrolytes were prepared by a phase inversion technique using DMAc solvent and water non-solvent. Cast film electrolytes filled with the same amount of SiO2 using DMAc were also made to compare physical and electrochemical properties. DMAc had a higher solubility to PVdF-based polymers than NMP, and DMAc produced highly porous structures with bigger cavities and influenced the reduction of crystallinity. Due to the highly porous nature of phase inversion membranes, the uptake of electrolyte solution reached more than 400% and room-temperature ionic conductivity was more than 10,3 S,·,cm,1. All of the liquid absorbed, however, did not necessarily contribute to increases in ionic conductivity. This was due to the different conduction modes of lithium cations in a complicated porous structure. Comprehensively optimizing all the properties measured, the phase inversion membrane electrolytes with 10,30 wt.-% SiO2 were the best candidates for use as the polymer electrolyte of lithium rechargeable batteries. [source] Effect of loaded TiO2 nanofiller on heteropolyacid-impregnated PVDF polymer electrolyte for the performance of dye-sensitized solar cellsPHYSICA STATUS SOLIDI (A) APPLICATIONS AND MATERIALS SCIENCE, Issue 2 2009Sambandam Anandan Abstract In order to improve the performance of the dye-sensitized solar cells based on polymer electrolytes, heteropolyacid impregnated polyvinylidene fluoride (PVDF) with loaded TiO2 nanofiller were prepared to mainly impede the back electron transfer processes. The prepared polymer electrolytes were well characterized before using them in solar cells. The SEM image confirms that the prepared polymer electrolytes have extended porosity with intersecting cavities of few nanometer in size. The functioning of the solar cells fabricated was monitored and the current,voltage characteristics were measured. The observed long term stability of the fabricated solar cells may be due to the redox couple mobility of the polymer chain increases upon addition of titania nanofiller. (© 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Thermal and transport properties of the polymer electrolyte based on poly(vinyl alcohol)-LiOH-H2OPHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 10 2005I. Delgado Abstract Solid polymer electrolytes consisting of poly(ethylene oxide) PEO and lithium trifluroacetate (CF3COOLi) with various salt mass fractions were prepared by the solvent casting method using acetonitrile. Temperature and concentration dependent impedance spectroscopy, as well as thermal analysis suggest the existence of a complex in the blends with an EO/Li ratio corresponding roughly to 4:1. The dc conductivity (,0) of the blends were very sensitive to the temperature (T) and their salt mass fraction (x), showing values in the range of 10-5 to 10-2 (S cm,1) at 330 K as the salt concentration was increased. The enhancement of conductivity with increasing temperature (5 orders of magnitude when the temperature changes from 300 to 353 K) was attributed to the high mobility of the Li+ ions as a consequence of the chain polymer flexibility and the increase of the free volume for ionic migration. (© 2005 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [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] Ionic conductivity in poly (L-leucine)1,3-diamino propane,lithium iodide solid polymer electrolytePOLYMERS FOR ADVANCED TECHNOLOGIES, Issue 3 2009N. H. Kaus Abstract The pelletized Poly(L-Leucine)-1,3-diamino propane,lithium iodide (LiI) samples have been prepared by using a low temperature sintering method. Results from impedance spectroscopy have proven this mixture to be a superionic material with maximum conductivity obtained in the range of 10,3,S/cm for the samples containing 50,wt% LiI. The high ionic conductivity achieved was due to the increased number of charge carrier from LiI. Improved conductivity could also be due to hopping of lithium ion through the side chain of polymer. Infrared spectroscopy showed that both LiI and poly amino acid may co-exist together. From the spectra it is revealed that the CO band at 1643,cm,1 shifted to higher wave number indicating that chelation of Li+ may have occurred at oxygen atom. Results from X-ray diffraction show that the prepared samples were partially crystalline in nature. Some of the peaks have disappeared and this confirmed that some complexation has occurred within the sample. Copyright © 2009 John Wiley & Sons, Ltd. [source] Highly conductive, oriented polymer electrolytes for lithium batteries,POLYMERS FOR ADVANCED TECHNOLOGIES, Issue 10-12 2002D. Golodnitsky Abstract In semicrystalline complexes of poly(ethylene oxide) (PEO) with different salts, such as lithium iodide, lithium trifluoromethanesulfonate (LiTF) and lithium trifluoromethanesulfonimide (LiTFSI), stretching induced longitudinal DC conductivity enhancement was observed, in spite of the formation of more ordered polymer electrolyte (PE) structure. It was found that the more amorphous the PE, the less its lengthwise conductivity is influenced by stretching. The results of our investigation suggest that ionic transport occurs preferentially along the PEO helical axis, at least in the crystalline phase, and that the rate-determining step of the lithium ion conduction in LiI:P(EO)20, LiTF:P(EO)20 polymer electrolytes below Tm is "interchain" hopping. Understanding ion transport processes is clearly a fertile field for research and development in the synthesis of new rigid polymers with ordered channels and composition appropriate for enhanced ionic conductivity. Copyright © 2003 John Wiley & Sons, Ltd. [source] Novel Polymer Electrolyte Membranes for Automotive Applications , Requirements and Benefits,FUEL CELLS, Issue 4 2004C. Wieser Abstract During the past few years, the feasibility of using polymer electrolyte fuel cells in automotive power trains at an impressive performance level has been proven repeatedly. However, current fuel cell stacks are still largely based on decade-old polymer electrolyte membrane technology thus limiting performance, durability, reliability, and cost of the fuel cell systems. The major challenge for membrane R&D constitutes the demand for polymer electrolytes that allow for system operation at higher temperatures and lower water management requirements without increased conduction losses. None the less, demanding automotive requirements will not compromise on other properties such as mechanical and chemical stability and gas permeability. [source] Novel amphiphilic polymer gel electrolytes based on (PEG- b -GMA)- co -MMAJOURNAL OF APPLIED POLYMER SCIENCE, Issue 3 2010Dan Luo Abstract Amphiphilic conetwork,structured copolymers containing different lengths of ethylene oxide (EO) chains as ionophilic units and methyl methacrylate (MMA) chains as ionophobic units were prepared by free radical copolymerization and characterized by FTIR and thermal analysis. Polymer gel electrolytes based on the copolymers complexed with liquid lithium electrolytes (dimethyl carbonate (DMC) : diethyl carbonate (DEC) : ethylene carbonate (EC) = 1 : 1 : 1 (W/W/W), LiPF6 1.0M) were characterized by differential scanning calorimetry and impedance spectroscopy. A maximum ion conductivity of 4.27 × 10,4 S/cm at 25oC was found for the polymer electrolyte based on (PEG2000- b -GMA)- co -MMA with long EO groups. Moreover, the effect of temperature on conductivity of the amphiphilic polymer electrolytes obeys the Arrhenius equation. The good room temperature conductivity of the polymer electrolytes is proposed to relate to the enhancement in the amorphous domain of the copolymers due to their amphiphilic conetwork structure. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010 [source] Ionic conductivity of solid polymer electrolytes for dye-sensitized solar cellsJOURNAL OF APPLIED POLYMER SCIENCE, Issue 6 2010Joo Wan Kim Abstract We developed an ionic conductivity model of solid polymer electrolytes for dye-sensitized solar cells (DSSCs) based on the Nernst,Einstein equation in which the diffusion coefficient is derived from the molecular thermodynamic model. We introduced concentration-dependence of the diffusion coefficient into the model, and the diffusion coefficient was expressed by differentiating the chemical potential by concentration. The ionic conductivities of polymer electrolytes (PEO/LiI/I2 system) were investigated at various temperatures and compositions. We prepared a set of PEO in which an EO : LiI mole ratio of 10 : 1 was kept constant for PEO·LiI·(I2)n compositions with n = 0.02, 0.05, 0.1, 0.15, 0.2, and 0.3 (mole ratio of LiI : I2). The ionic conductivities of the electrolytes were measured using a stainless steel/polymer-electrolyte/stainless steel sandwich-type electrode structure using alternating current impedance analysis. The values calculated using the proposed model agree well with experimental data. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010 [source] Lewis acid,base property of P(VDF- co -HFP) measured by inverse gas chromatographyJOURNAL OF APPLIED POLYMER SCIENCE, Issue 3 2008Baoli Shi Abstract Poly (vinylidene fluoride- co -hexafluoropropylene) P(VDF- co -HFP) is an excellent material for polymer electrolytes of lithium ion battery. To enhance the lithium ion transference number, some metal oxides were often embedded into P(VDF- co -HFP). The promising mechanism for the increase in lithium ionic conductivity was Lewis acid-base theory. In this experiment, the Lewis acid,base properties of P(VDF- co -HFP) were measured by inverse gas chromatography (IGC). The Lewis acid constant Ka of P(VDF- co -HFP) is 0.254, and the base constant Kb is 1.199. Compared with other polymers characterized by IGC, P(VDF- co -HFP) is the strongest Lewis basic polymers. Except aluminum ion, lithium ion is the strongest Lewis acidic ion according to their , value of Lewis acids. Therefore, a strong Lewis acid,base interaction will exist between lithium ion and P(VDF- co -HFP). This will restrict the transference of lithium ion in P(VDF- co -HFP). To enhance the lithium ion transference by blending other metal ions into P(VDF- co -HFP), it is suggested that the preferential ions should be Al3+, Mg2+, Na+, and Ca2+ because these metal ions have relative large , values. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008 [source] Density functional theory studies on the dissociation energies of metallic salts: relationship between lattice and dissociation energiesJOURNAL OF COMPUTATIONAL CHEMISTRY, Issue 8 2001Chang Kon Kim Abstract The formation and physicochemical properties of polymer electrolytes strongly depend on the lattice energy of metal salts. An indirect but efficient way to estimate the lattice energy through the relationship between the heterolytic bond dissociation and lattice energies is proposed in this work. The heterolytic bond dissociation energies for alkali metal compounds were calculated theoretically using the Density Functional Theory (DFT) of B3LYP level with 6-311+G(d,p) and 6-311+G(2df,p) basis sets. For transition metal compounds, the same method was employed except for using the effective core potential (ECP) of LANL2DZ and SDD on transition metals for 6-311+G(d,p) and 6-311+G(2df,p) calculations, respectively. The dissociation energies calculated by 6-311+G(2df,p) basis set combined with SDD basis set were better correlated with the experimental values with average error of ca. ±1.0% than those by 6-311+G* combined with the LANL2DZ basis set. The relationship between dissociation and lattice energies was found to be fairly linear (r>0.98). Thus, this method can be used to estimate the lattice energy of an unknown ionic compound with reasonably high accuracy. We also found that the dissociation energies of transition metal salts were relatively larger than those of alkaline metal salts for comparable ionic radii. © 2001 John Wiley & Sons, Inc. J Comput Chem 22: 827,834, 2001 [source] Synthesis and characterization of poly(ethylene oxide- co -ethylene carbonate) macromonomers and their use in the preparation of crosslinked polymer electrolytesJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 7 2006Anette Munch Elmér Abstract Methacrylate-functionalized poly(ethylene oxide- co -ethylene carbonate) macromonomers were prepared in two steps by the anionic ring-opening polymerization of ethylene carbonate at 180 °C, with potassium methoxide as the initiator, followed by the reaction of the terminal hydroxyl groups of the polymers with methacryloyl chloride. The molecular weight of the polymer went through a maximum after approximately 45 min of polymerization, and the content of ethylene carbonate units in the polymer decreased with the reaction time. A polymer having a number-average molecular weight of 2650 g mol,1 and an ethylene carbonate content of 28 mol % was selected and used to prepare a macromonomer, which was subsequently polymerized by UV irradiation in the presence of different concentrations of lithium bis(trifluoromethanesulfonyl)imide salt. The resulting self-supportive crosslinked polymer electrolyte membranes reached ionic conductivities of 6.3 × 10,6 S cm,1 at 20 °C. The coordination of the lithium ions by both the ether and carbonate oxygens in the polymer structure was indicated by Fourier transform infrared spectroscopy. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 2195,2205, 2006 [source] Solid polymer electrolytes I, preparation, characterization, and ionic conductivity of gelled polymer electrolytes based on novel crosslinked siloxane/poly(ethylene glycol) polymersJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 9 2004Ping-Lin Kuo Abstract A series of crosslinked siloxane/poly(ethylene glycol) (Si,PEG) copolymers were synthesized from the reactive methoxy-functional silicone resin (Si resin) and PEGs with different molecular weights via two kinds of crosslinking reactions during an in situ curing stage. One of the crosslinking reactions is the self-condensation between two methoxy groups in the Si resin, and another one is an alkoxy-exchange reaction between the methoxy group in the Si resin and the OH group in PEG. The synthesized crosslinked copolymers were characterized by Fourier transform infrared spectroscopy, DSC, and 13C NMR. The crosslinked copolymers were stable in a moisture-free environment, but the SiOC linkages were hydrolyzed in humid conditions. The gel-like solid polymer electrolytes (SPEs) were prepared by impregnating these crosslinked Si,PEG copolymers in a propylene carbonate (LiClO4/PC) solution. The highest conductivity reached 2.4 × 10,4 S cm,1 at 25 °C and increased to 8.7 × 10,4 S cm,1 at 85 °C. The conductivities of these gel-type SPEs were affected by the content of LiClO4/PC, the molecular weights of PEGs, and the weight fraction of the Si resin. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 2051,2059, 2004 [source] Solid polymer electrolytes III: Preparation, characterization, and ionic conductivity of new gelled polymer electrolytes based on segmented, perfluoropolyether-modified polyurethaneJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 4 2002Chi-Chang Chen Abstract New segmented polyurethanes with perfluoropolyether (PFPE) and poly(ethylene oxide) blocks were synthesized from a fluorinated macrodiol mixed with poly(ethylene glycol) (PEG) in different ratios as a soft segment, 2,4-toluene diisocyanate as a hard segment, and ethylene glycol as a chain extender. Fourier transform infrared, NMR, and thermal analysis [differential scanning calorimetry and thermogravimetric analysis (TGA)] were used to characterize the structures of these copolymers. The copolymer films were immersed in a liquid electrolyte (1 M LiClO4/propylene carbonate) to form gel-type electrolytes. The ionic conductivities of these polymer electrolytes were investigated through changes in the copolymer composition and content of the liquid electrolyte. The relative molar ratio of PFPE and PEG in the copolymer played an important role in the conductivity and the capacity to retain the liquid electrolyte solution. The copolymer with a 50/50 PFPE/PEG ratio, having the lowest decomposition temperature shown by TGA, exhibited the highest ionic conductivity and lowest activation energy for ion transportation. The conductivities of these systems were about 10,3 S cm,1 at room temperature and 10,2 S cm,1 at 70 °C; the films immersed in the liquid electrolyte with an increase of 70 wt % were homogenous with good mechanical properties. © 2002 John Wiley & Sons, Inc. J Polym Sci Part A: Polym Chem 40: 486,495, 2002; DOI 10.1002/pola.10119 [source] Dye-Sensitized Solar Cells Based on TiO2 Coatings with Dual Size-Scale PorosityJOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 9 2009Lai Qi Dye-sensitized solar cells (DSSC) with efficiencies greater than 4% were produced with templated "inverse opal" titania coatings. A novel one-step method produces uniform and crack-free coatings made using commercially available titania nanoparticles with high reproducibility and uniformity. In this research, a volatile solvent electrolyte was tested; however, it shows proof-of-concept that larger pore volumes can be created for increased penetration of more viscous electrolytes that can be utilized in high-efficiency cells. This dual size-scale porosity film is a promising structure for DSSC applications, especially for those solid-state or quasi-solid-state cells that require polymer electrolytes. [source] | ||||||||||||||||||||||||||||