共查询到20条相似文献,搜索用时 31 毫秒
1.
Prasanth Raghavan Jae-Won Choi Jou-Hyeon Ahn Gouri Cheruvally Ghanshyam S. Chauhan Hyo-Jun Ahn Changwoon Nah 《Journal of power sources》2008
Composite membranes of poly(vinylidene fluoride-co-hexafluoropropylene) {P(VdF-HFP)} and different composition of silica have been prepared by electrospinning polymer solution containing in situ generated silica. These membranes are made up of fibers of 1–2 μm diameters. These fibers are stacked in layers to produce fully interconnected pores that results in high porosity. Polymer electrolytes were prepared by immobilizing 1 M LiPF6 in ethylene carbonate (EC)/dimethyl carbonate (DMC) in the membranes. The composite membranes exhibit a high electrolyte uptake of 550–600%. The optimum electrochemical properties have been observed for the polymer electrolyte containing 6% in situ silica to show ionic conductivity of 8.06 mS cm−1 at 20 °C, electrolyte retention ratio of 0.85, anodic stability up to 4.6 V versus Li/Li+, and a good compatibility with lithium metal resulting in low interfacial resistance. A first cycle specific capacity of 170 mAh g−1 was obtained when the polymer electrolyte was evaluated in a Li/lithium iron phosphate (LiFePO4) cell at 0.1 C-rate at 25 °C, corresponding to 100% utilization of the cathode material. The properties of composite membrane prepared with in situ silica were observed to be comparatively better than the one prepared by direct addition of silica. 相似文献
2.
Xin Li Gouri Cheruvally Jae-Kwang Kim Jae-Won Choi Jou-Hyeon Ahn Ki-Won Kim Hyo-Jun Ahn 《Journal of power sources》2007
Electrospinning parameters are optimized for the preparation of fibrous membranes of poly(vinylidene fluoride-co-hexafluoropropylene) {P(VdF-HFP)} that consist of layers of uniform fibres of average diameter 1 μm. Electrospinning of a 16 wt.% solution of the polymer in acetone/N,N-dimethylacetamide (DMAc) (7/3, w/w) at an applied voltage of 18 kV results in obtaining membranes with uniform morphology. Polymer electrolytes (PEs) are prepared by activating the membrane with liquid electrolytes. The fully interconnected porous structure of the host polymer membrane enables high electrolyte uptake and ionic conductivities of 10−3 S cm−1 order at 20 °C. The PEs have electrochemical stability at potentials higher than 4.5 V versus Li/Li+. A PE based on a membrane with 1 M LiPF6 in ethylene carbonate (EC)/dimethyl carbonate (DMC), which exhibits a low and stable interfacial resistance on lithium metal, is evaluated for discharge capacity and cycle properties in Li/LiFePO4 cells at room temperature and different current densities. A remarkably good performance with a high initial discharge capacity and low capacity fading on cycling is obtained. 相似文献
3.
R.L. Lavall S. Ferrari M. Marzantowicz A. Magistris S. Lazzaroni 《Journal of power sources》2010,195(17):5761-373
Polymer electrolytes were prepared from thermoplastic polyurethane with addition of mixture of ionic liquid N-ethyl(methylether)-N-methylpyrrolidinium trifluoromethanesulfonimmide (PYRA12O1TFSI), lithium bis(trifluoromethanesulfoneimide) salt and propylene carbonate. The electrolytes characterization was performed by thermogravimetric analysis, differential scanning calorimetry and scanning electron microscopy. The electrical properties were investigated in detail by impedance spectroscopy with the aid of equivalent circuit fitting of the impedance spectra. A model describing temperature evolution of ionic conductivity and the properties of electrolyte/blocking electrode interface was developed. The electrochemical stability of the electrolytes was studied by linear voltammetry. Our results indicate that the studied electrolytes have good self-standing characteristics, and also a sufficient level of thermal stability and a fairly good electrochemical window. The ionic conductivity increases with increasing amount of mixture, and the character of temperature dependence of conductivity indicates decoupling of ion transport from polymer matrix. For studied system, the highest value of ionic conductivity measured at room temperature was 10−4 S cm−1. 相似文献
4.
Prasanth RaghavanJames Manuel Xiaohui ZhaoDul-Sun Kim Jou-Hyeon Ahn Changwoon Nah 《Journal of power sources》2011,196(16):6742-6749
Electrospun membranes of polyacrylonitrile are prepared, and the electrospinning parameters are optimized to get fibrous membranes with uniform bead-free morphology. The polymer solution of 16 wt.% in N,N-dimethylformamide at an applied voltage of 20 kV results in the nanofibrous membrane with average fiber diameter of 350 nm and narrow fiber diameter distribution. Gel polymer electrolytes are prepared by activating the nonwoven membranes with different liquid electrolytes. The nanometer level fiber diameter and fully interconnected pore structure of the host polymer membranes facilitate easy penetration of the liquid electrolyte. The gel polymer electrolytes show high electrolyte uptake (>390%) and high ionic conductivity (>2 × 10−3 S cm−1). The cell fabricated with the gel polymer electrolytes shows good interfacial stability and oxidation stability >4.7 V. Prototype coin cells with gel polymer electrolytes based on a membrane activated with 1 M LiPF6 in ethylene carbonate/dimethyl carbonate or propylene carbonate are evaluated for discharge capacity and cycle property in Li/LiFePO4 cells at room temperature. The cells show remarkably good cycle performance with high initial discharge properties and low capacity fade under continuous cycling. 相似文献
5.
G.B. Appetecchi G.-T. Kim M. Carewska D. Mecerreyes 《Journal of power sources》2010,195(11):3668-9803
The electrochemical properties of solvent-free, ternary polymer electrolytes based on a novel poly(diallyldimethylammonium) bis(trifluoromethanesulfonyl)imide polymeric ionic liquid (PIL) as polymer host and incorporating PYR14TFSI ionic liquid and LiTFSI salt are reported. The PIL-LiTFSI-PYR14TFSI electrolyte membranes were found to be chemically stable even after prolonged storage times in contact with lithium anode and thermally stable up to 300 °C. Particularly, the PIL-based electrolytes exhibited acceptable room temperature conductivity with wide electrochemical stability window, time-stable interfacial resistance values and good lithium stripping/plating performance. Preliminary battery tests have shown that Li/LiFePO4 solid-state cells are capable to deliver above 140 mAh g−1 at 40 °C with very good capacity retention up to medium rates. 相似文献
6.
Nonwoven films of composites of thermoplastic polyurethane (TPU) with different proportion of poly(vinylidene fluoride) (PVdF) (80, 50 and 20%, w/w) are prepared by electrospinning 9 wt% polymer solution at room temperature. Then the gel polymer electrolytes (GPEs) are prepared by soaking the electrospun TPU-PVdF blending membranes in 1 M LiClO4/ethylene carbonate (EC)/propylene carbonate (PC) for 1 h. The gel polymer electrolyte (GPE) shows a maximum ionic conductivity of 3.2 × 10−3 S cm−1 at room temperature and electrochemical stability up to 5.0 V versus Li+/Li for the 50:50 blend ratio of TPU:PVdF system. At the first cycle, it shows a first charge-discharge capacity of 168.9 mAh g−1 when the gel polymer electrolyte (GPE) is evaluated in a Li/PE/lithium iron phosphate (LiFePO4) cell at 0.1 C-rate at 25 °C. TPU-PVdF (50:50, w/w) based gel polymer electrolyte is observed much more suitable than the composite films with other ratios for high-performance lithium rechargeable batteries. 相似文献
7.
Mingtao LiLi Yang Shaohua Fang Siming DongShin-ichi Hirano Kazuhiro Tachibana 《Journal of power sources》2011,196(20):8662-8668
The electrochemical properties of solvent-free, quaternary polymer electrolytes based on a novel polymeric ionic liquid (PIL) as polymer host and incorporating 1g13TFSI ionic liquid, LiTFSI salt and nano-scale silica are reported. The PIL-LiTFSI-1g13TFSI-SiO2 electrolyte membranes are found to be chemically stable even at 80 °C in contact with lithium anode and thermally stable up to 320 °C. Particularly, the quaternary polymer electrolytes exhibit high lithium ion conductivity at high temperature, wide electrochemical stability window, time-stable interfacial resistance values and good lithium stripping/plating performance. Batteries assembled with the quaternary polymer electrolyte at 80 °C are capable to deliver 140 mAh g−1 at 0.1C rates with very good capacity retention. 相似文献
8.
Yinzheng Liang Liwen JiBingkun Guo Zhan LinYingfang Yao Ying LiMataz Alcoutlabi Yiping QiuXiangwu Zhang 《Journal of power sources》2011,196(1):436-441
Lithium lanthanum titanate oxide (LLTO)/polyacrylonitrile (PAN) submicron composite fiber-based membranes were prepared by electrospinning dispersions of LLTO ceramic particles in PAN solutions. These ionic-conducting LLTO/PAN composite fiber-based membranes can be directly used as lithium-ion battery separators due to their unique porous structure. Ionic conductivities were evaluated after soaking the electrospun LLTO/PAN composite fiber-based membranes in a liquid electrolyte, 1 M lithium hexafluorophosphate (LiPF6) in ethylene carbonate (EC)/ethyl methyl carbonate (EMC) (1:1 vol). It was found that, among membranes with various LLTO contents, 15 wt.% LLTO/PAN composite fiber-based membranes provided the highest ionic conductivity, 1.95 × 10−3 S cm−1. Compared with pure PAN fiber membranes, LLTO/PAN composite fiber-based membranes had greater liquid electrolyte uptake, higher electrochemical stability window, and lower interfacial resistance with lithium. In addition, lithium//1 M LiPF6/EC/EMC//lithium iron phosphate cells containing LLTO/PAN composite fiber-based membranes as the separator exhibited high discharge specific capacity of 162 mAh g−1 and good cycling performance at 0.2 C rate at room temperature. 相似文献
9.
Polymer electrolyte membrane fuel cells (PEMFCs) are very promising as future energy source due to their high-energy conversion efficiency and will help to solve the environmental concerns of energy production. Polymer electrolyte membrane (PEM) is recognised as the key element for an efficient PEMFC. Chemically crosslinked composite membranes consisting of a poly(vinyl alcohol-co-vinyl acetate-co-itaconic acid) (PVACO) and phosphomolybdic acid (PMA) have been prepared by solution casting and evaluated as proton conducting polymer electrolytes. The proton conductivity of the membranes is investigated as a function of PMA composition, crosslinking density and temperature. The membranes have also been characterized by FTIR spectroscopy, TGA, AFM and TEM. The proton conductivity of the composite membranes is of the order of 10−3 S cm−1 and shows better resistance to methanol permeability than Nafion 117 under similar measurement conditions. 相似文献
10.
A. Chiappone Jijeesh R. NairC. Gerbaldi L. JabbourR. Bongiovanni E. ZenoD. Beneventi N. Penazzi 《Journal of power sources》2011,196(23):10280-10288
Methacrylic-based thermo-set gel-polymer electrolyte membranes obtained by a very easy, fast and reliable free radical photo-polymerisation process and reinforced with microfibrillated cellulose particles are here presented. The morphology of the composite electrolytes is investigated by scanning electron microscopy and their thermal behaviour (characteristic temperatures, degradation temperature) are investigated by thermo-gravimetric analysis and differential scanning calorimetry. The composite membranes prepared exhibit excellent mechanical properties, with a Young's modulus as high as about 80 MPa at ambient temperature. High ionic conductivity (approaching 10−3 S cm−1 at 25 °C) and good overall electrochemical performances are maintained, enlightening that such specific approach would make these hybrid organic, cellulose-based composite polymer electrolyte systems a strong contender in the field of thin and flexible lithium based power sources. 相似文献
11.
Blends of PVdF-HFP and ionic liquids (ILs) are interesting for application as electrolytes in plastic Li batteries. They combine the advantages of the gel polymer electrolytes (GPEs) swollen by conventional organic liquid electrolytes with the nonflammability, and high thermal and electrochemical stability of ILs.In this work we prepared and characterized PVdF-HFP composite membranes swollen with a solution of LiTFSI in ether-functionalized pyrrolidinium-imide ionic liquid (PYRA12O1TFSI). The membranes were filled in with two different types of silica: (i) mesoporous SiO2 (SBA-15) and (ii) a commercial nano-size one (HiSil™ T700). The ionic conductivity and the electrochemical properties of the gel electrolytes were studied in terms of the nature of the filler.The thermal and the transport properties of the composite membranes are similar. In particular, room temperature ionic conductivities higher than 0.25 mS cm−1 are easily obtained at defined filler contents. However, the mesoporous filler guarantees higher lithium transference numbers, a more stable electrochemical interface and better cycling performances. Contrary to the HiSil™-based membrane, the Li/LiFePO4 cells with PVdF-HFP/PYRA12O1TFSI-LiTFSI films containing 10 wt% of SBA-15 show good charge/discharge capacity, columbic efficiency close to unity, and low capacity losses at medium C-rates during 180 cycles. 相似文献
12.
Poly(2-ethoxyethyl methacrylate) polymer gel electrolytes containing immobilised lithium bis(oxalato)borate in aprotic carbonates: propylene carbonate (PC), propylene carbonate–ethylene carbonate (PC–EC 50:50 vol.%) and diethyl carbonate–ethylene carbonate (DEC–EC 50:50 vol.%) were prepared by a direct radical polymerisation. The electrolyte composition was optimised to achieve suitable ionic conductivity 0.5 and 2.4 mS cm−1 at 25 and 70 °C respectively along with good mechanical properties. The electrochemical stability up to 5.1 V vs. Li/Li+ was determined on gold electrode by voltammetrical measurements. The polymer electrolytes with high-boiling solvents (PC and PC/EC) showed higher thermal stability (up to 110–120 °C) compared to the liquid electrolytes. The proposed area of application is in the lithium-ion batteries with cathodes operating at elevated temperatures of 70 °C, where higher electrochemical stability of the polymer electrolytes is employed. 相似文献
13.
A star-shaped siloxane acrylate with a different number of repeating units of oligo(ethylene oxide) (EO) was synthesized as a cross-linker of solid polymer electrolytes. The cross-linked solid polymer electrolytes blended with the ionic conducting plasticizers, such as low molecular weight poly(ethylene oxide)dimethyl ether (PEGDME) were prepared by the in situ thermal curing of the star-shaped siloxane acrylate. Different morphologies of the cross-linked polymer electrolytes were observed according to the number of repeating units of EO (n) in the cross-linker. A micro-phase separated solid polymer electrolyte was obtained when the n of cross-linker was 1. When the n of cross-linker was larger than 1, homogeneously blended solid polymer electrolytes were prepared. The ionic conductivity was measured to be 6.3 to 7.8 × 10−4 S cm−1 with 80 wt.% PEGDME at 30 °C. The ionic conductivity of the micro-phase separated solid polymer electrolyte was slightly higher than that of the homogeneously blended solid polymer electrolyte. The electrochemical stability window of the resulting solid polymer electrolyte could be extended to up to 4.8 V versus Li/Li+ reference electrode. 相似文献
14.
A novel composite polymer electrolyte membrane composed of a PVA polymer host and montmorillonite (MMT) ceramic fillers (2–20 wt.%), was prepared by a solution casting method. The characteristic properties of the PVA/MMT composite polymer membrane were investigated using thermal gravimetric analysis (TGA), differential scanning calorimetry (DSC), dynamic mechanical analysis (DMA), scanning electron microscopy (SEM), and micro-Raman spectroscopy, and the AC impedance method. The PVA/MMT composite polymer membrane showed good thermal and mechanical properties and high ionic conductivity. The highest ionic conductivity of the PVA/10 wt.%MMT composite polymer membrane was 0.0368 S cm−1 at 30 °C. The methanol permeability (P) values were 3–4 × 10−6 cm2 s−1, which was lower than that of Nafion 117 membrane of 5.8 × 10−6 cm2 s−1. It was revealed that the addition of MMT fillers into the PVA matrix could markedly improve the electrochemical properties of the PVA/MMT composite membranes; which can be accomplished by a simple blend method. The maximum peak power density of the DMFC with the PtRu anode based on Ti-mesh in a 2 M H2SO4 + 2 M CH3OH solution was 6.77 mW cm−2 at ambient pressure and temperature. As a result, the PVA/MMT composite polymer appears to be a good candidate for the DMFC applications. 相似文献
15.
A novel polymer-inorganic composite electrolyte for direct methanol alkaline fuel cells (DMAFCs) is prepared by physically blending fumed silica (FS) with polyvinyl alcohol (PVA) to suppress the methanol permeability of the resulting nano-composites. Methanol permeability is suppressed in the PVA/FS composite when comparing with the pristine PVA membrane. The PVA membrane and the PVA/FS composite are immersed in KOH solutions to prepare the hydroxide-conducting electrolytes. The ionic conductivity, cell voltage and power density are studied as a function of temperature, FS content, KOH concentration and methanol concentration. The PVA/FS/KOH electrolyte exhibits higher ionic conductivity and higher peak power density than the PVA/KOH electrolyte. In addition, the concentration of KOH in the PVA/FS/KOH electrolytes plays a major role in achieving higher ionic conductivity and improves fuel cell performance. An open-circuit voltage of 1.0 V and a maximum power density of 39 mW cm−2 are achieved using the PVA/(20%)FS/KOH electrolyte at 60 °C with 2 M methanol and 6 M KOH as the anode fuel feed and with humidified oxygen at the cathode. The resulting maximum power density is higher than the literature data reported for DMAFCs prepared with hydroxide-conducting electrolytes and anion-exchange membranes. The long-term cell performance is sustained during a 100-h continuous operation. 相似文献
16.
Diganta SaikiaHao-Yiang Wu Yu-Chi PanChi-Pin Lin Kai-Pin HuangKan-Nan Chen George T.K. FeyHsien-Ming Kao 《Journal of power sources》2011,196(5):2826-2834
A new plasticized poly(vinylidene fluoride-co-hexafluoropropylene (PVdF-HFP)/PPG-PEG-PPG diamine/organosilane blend-based polymer electrolyte system has been synthesized and characterized. The structural and electrochemical properties of the electrolytes thus obtained were systematically investigated by a variety of techniques including differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), tensile test, Fourier transform infrared spectroscopy (FTIR), 13C and 29Si solid-state NMR, AC impedance, linear sweep voltammetry (LSV) and charge-discharge measurements. The FTIR and NMR results provided the information about the interaction among the constituents in the blend polymer membrane. The present blend polymer electrolyte exhibits several advantageous electrochemical properties such as ionic conductivity up to 1.3 × 10−2 S cm−1 at room temperature, high value of Li+ transference number (t+ = 0.82), electrochemical stability up to 6.4 V vs. Li/Li+ with the platinum electrode, and stable charge-discharge cycles for lithium-ion batteries. 相似文献
17.
A type of anhydrous proton-conducting membranes are prepared via in situ cross-linking of polymerizable oils containing polyamidoamine (PAMAM) dendrimer-based macromolecular protic ionic liquids (PILs). The resultant composite membranes are transparent, flexible, and thermally stable up to 350 °C. Under anhydrous conditions, the macromolecular PIL-based membranes show proton conductivity of 1.2 × 10−2 S cm−1 at 160 °C, which is higher than that of the membranes containing small-molecule PILs. Furthermore, the macromolecular PIL-based composite membranes have much better PIL retention ability than which containing small-molecule PILs. These properties make this type of macromolecular PIL-based membranes suitable for high-temperature anhydrous polymer electrolyte membrane fuel cells. 相似文献
18.
New types of dimensionally stable, flexible gel-type electrolyte membranes with a relatively wide electrochemical stability, high lithium ion conductivity and other desirable properties have been prepared by immobilizing N-n-butyl-N-ethylpyrrolidinium N,N-bis(trifluoromethane)sulfonimide-lithium N,N-bis(trifluoromethane)sulfonimide (Py24TFSI-LiTFSI), ionic liquid, IL, solutions in a poly(vinylidene fluoride)-hexafluoropropylene copolymer (PVdF-HFP) matrix. The addition of a discrete amount of ethylene and propylene carbonate (EC–PC), solvent mixture to the membranes resulted in an improvement of the ionic conductivity and in a stabilization of the interface with the lithium electrode. These IL-based gel type membranes can operate without degradation up to a temperature of 110 °C where they reach conductivity values of the order of 10−2 S cm−1. All these properties make these polymer electrolyte membranes of interest for applications as separators in advanced lithium batteries. 相似文献
19.
Seung-Yul Lee 《Journal of power sources》2010,195(18):5909-1495
We have demonstrated that a protic ionic liquid, diethylmethylammonium trifluoromethanesulfonate ([dema][TfO]) functions as a proton conductor and is suitable for use as an electrolyte in H2/O2 fuel cells, which can be operated at temperatures higher than 100 °C under non-humidified conditions. In this study, in order to fabricate a polymer electrolyte fuel cell, matrix polymers for [dema][TfO] are explored and sulfonated polyimides (SPI), in which the sulfonic acid groups are in diethylmethylammonium form, are found to be highly compatible with [dema][TfO]. Polymer electrolyte membranes for non-humidified fuel cells are prepared by the solvent casting method using SPI and [dema][TfO]. The SPI, with an ion exchange capacity of 2.27 meq g−1, can retain four times its own weight of [dema][TfO] and produces uniform, tough, and transparent composite membranes. The composite membranes have good thermal stability (>300 °C) and ionic conductivity (>10−2 S cm−1 at 120 °C when the [dema][TfO] content is higher than 67 wt%) under anhydrous conditions. In the H2/O2 fuel cell operation using a composite membrane without humidification, a current density higher than 240 mA cm−2 is achieved with a maximum power density of 100 mW cm−2 at 80 °C. 相似文献
20.
Anne-Laure Pont Rebeca MarcillaIratxe De Meatza Hans GrandeDavid Mecerreyes 《Journal of power sources》2009
A new family of polymeric ionic liquids having pyrrolidinium cation pendant units was synthesized from commercially available poly(diallyldimethylammonium) chloride. A simple anion exchange procedure was applied to the poly(diallyldimethylammonium) chloride using different salts such as LiTFSI, KPF6, LiBF4 and NaDBSA. The anion exchange reaction was quantitative as confirmed by NMR, FT-IR and titration experiments. Among these polymers, poly(diallyldimethylammonium) bis(trifluoromethanesulfonyl)imide (TFSI) showed excellent performance as polymer matrix for polymer electrolyte compositions together with pyrrolidinium ionic liquid and lithium salt having a similar TFSI counter-anion. In this sense, free standing mechanically stable transparent polymer films showing an ionic conductivity higher than 10−4 S cm−1 at room temperature were prepared and characterized. Furthermore, the polymer electrolytes presented a wide electrochemical stability window (7.0 V) which makes them interesting candidates for solid-state lithium batteries. 相似文献