Effect of crosslinkers on the preparation and properties of ETFE‐based radiation‐grafted polymer electrolyte membranes

This study concerns a comparative study of three crosslinkers, divinylbenzene (DVB), 1,2‐bis(p,p‐vinylphenyl)ethane (BVPE), and triallyl cyanurate (TAC) crosslinked poly(ethylene‐co‐tetrafluoroethylene) (ETFE)‐based radiation‐grafted membranes, which were prepared by radiation grafting of p‐methylstyrene onto ETFE films and subsequent sulfonation. The effect of the different types and contents of the crosslinkers on the grafting and sulfonation, and the properties such as water uptake, proton conductivity, and thermal/chemical stability of the resulting polymer electrolyte membranes were investigated in detail. Introducing crosslink structure into the radiation‐grafted membranes leads to a decrease in proton conductivity due to the decrease in water uptake. The thermal stability of the crosslinked radiation‐grafted membranes is also somewhat lower than that of the noncrosslinked one. However, the crosslinked radiation‐grafted membranes show significantly higher chemical stability characterized in the 3% H₂O₂ at 50°C. Among the three crosslinkers, the DVB shows a most pronounced efficiency on the crosslinking of the radiation‐grafted membranes, while the TAC has no significant influence; the BVPE is a mild and effective crosslinker, showing the moderate influence between the DVB and TAC crosslinkers. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 4565–4574, 2006     

Preparation and properties of sulfonated ETFE‐g‐polyvinyltoluene membranes for application in fuel cells

A new polymer electrolyte membrane prepared by radiation grafting of vinyltoluene into poly(ethylene‐co‐tetrafluoroethylene) (ETFE) film and subsequent sulfonation was developed for application in fuel cells. The effect of grafting condition on the degree of grafting was investigated in detail. Results indicated that the degree of grafting can be controlled over a wide range. The grafted films were sulfonated in a chlorosulfonic acid solution to obtain the polymer electrolyte membranes, which were characterized with respect to their use in fuel cells. It is concluded that the substituted methyl group on the vinyltoluene can improve the chemical stability of the resulting membranes, and the crosslinked ETFE‐g‐poly(vinyltoluene‐co‐divinylbenzene) membranes can be proposed for the future development of alternative low‐cost and high‐performance membranes for fuel cells. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 2661–2667, 2006     

Influence of Radiation‐Induced Grafting Process on Mechanical Properties of ETFE‐Based Membranes for Fuel Cells

The mechanical stability is, in addition to thermal and chemical stability, a primary requirement of polymer electrolyte membranes in fuel cells. In this study, the impact of grafting parameters and preparation steps on stress–strain properties of ETFE‐based proton conducting membranes, prepared by radiation‐induced grafting and subsequent sulphonation, was studied. No significant change in the mechanical properties of the ETFE base film was observed below an irradiation dose of 50 kGy. It was shown that the elongation at break decreases with increasing both the crosslinker concentration and graft level (GL). However, the tensile strength was positively affected by the crosslinker concentration. Yield strength and modulus of elasticity are almost unaffected by the introduction of crosslinker. Interestingly, yield strength and modulus of elasticity increase gradually with GL without noticeable change of the inherent crystallinity of grafted films. The most brittle membranes are obtained via the combination of high GL and crosslinker concentration. The optimised ETFE‐based membrane (GL of ∼25%, 5% DVB v/v), shows mechanical properties superior to those of Nafion® 112 membrane. The obtained results were correlated qualitatively to the other ex situ properties, including crystallinity, thermal properties and water uptake of the grafted membranes.     

Thermal properties of proton-conducting radiation-grafted membranes

Proton-exchange membranes are required to exhibit chemical, mechanical, and thermal stability for fuel cell applications. The present investigation has been carried out to explore the thermal behavior of poly(ethylene-alt-tetrafluoroethylene) (ETFE)-based proton-conducting membranes, both uncrosslinked and crosslinked, prepared by radiation grafting and subsequent sulfonation. The influence of preparation steps (irradiation, grafting, sulfonation, crosslinking) on the thermal degradation, crystallinity, and melting behavior of membranes with varying degree of grafting was examined. ETFE base film and grafted films were studied as the reference materials. Furthermore, poly(tetrafluoroethylene-co-hexafluoropropylene)-based grafted films and membranes were investigated as well for comparison. Membrane preparation steps, degree of grafting, crosslinking, type of base polymer have considerable influence on the thermal properties of membranes. The crystallinity of the films decreases slightly by grafting, while a significant decrease was observed after sulfonation. For instance, crystallinity decreased from 37% (pristine ETFE) to 36% (uncrosslinked grafted film) and 23% (uncrosslinked ETFE-based membrane). On the other hand, the melting temperature of the base polymer was almost unaffected by irradiation and grafting. The crosslinked ETFE-based membranes exhibit a slightly higher melting temperature (262.5°C) than their corresponding grafted films (261.3°C) and the base film (260.6°C). © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Partially Sulfonated Poly(1,4‐phenylene ether‐ether‐sulfone) and Poly(vinylidene fluoride) Blend Membranes for Fuel Cells

Blend membranes based on high conductive sulfonated poly(1,4‐phenylene ether‐ether‐sulfone) (SPEES) and poly(vinylidene fluoride) (PVDF) having excellent chemical stability were prepared and characterized for direct methanol fuel cells. The effects of PVDF content on the proton conductivity, water uptake, and chemical stability of SPEES/PVDF blend membranes were investigated. The morphology, miscibility, thermal, and mechanical properties of blend membranes were also studied by means of scanning electron microscopy (SEM), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), and dynamic mechanical analysis (DMA) measurements. The blend membrane containing 90 wt.% SPEES (degree of sulfonation – DS = 72%) and 10 wt.% PVDF (M_w = 180,000) exhibits optimum properties among various SPEES72/PVDF membranes. Addition of PVDF enhanced resistance of the SPEES membrane against peroxide radicals and methanol significantly without deterioration of its proton conductivity. It's proton conductivity at 80 °C and 100% relative humidity is higher than Nafion 115 while it's methanol permeability is only half of that of Nafion 115 at 80 °C. The direct methanol fuel cell performance of the SPEES membranes was better than that of Nafion 115 membrane at 80 °C.     

Synthesis of fluorinated polymer electrolyte membranes by radiation grafting and atom transfer radical polymerization techniques

A novel polymer electrolyte membrane was synthesized by radiation-induced grafting and consequent atom transfer radical polymerization (ATRP). First, bromine-containing perfluorinated grafts were prepared by radiation grafting of 2-bromotetrafluoroethyl trifluorovinyl ether (BrTFF) into a poly(ethylene-co-tetrafluoroethylene) (ETFE) film. Then, the bromine atoms in the ETFE-g-PBrTFF grafted films were acted as initiators, and the films were treated with Cu(I)-based catalytic system of a CuBr and 2,2′-bipyridyl (bpy) for the ATRP. By adjusting the molar ratio of initiator/CuBr/bpy and the reaction temperature, branched poly(styrene) with a grafting yield of above 100% on the poly(BrTFF) main chains was constructed in ETFE-g-PBrTFF films. Thermal analysis revealed that the perfluorinated poly(BrTFF) main chains were miscible to ETFE, whereas the hydrocarbon poly(styrene) branches were phase-separated from the ETFE-g-PBrTFF film. Sulfonic groups could be further introduced into the poly(styrene) grafts of ETFE-g-PBrTFF-g-PS films with homogeneous distribution in a perpendicular direction to the membrane surface. The resulting membrane with a styrene grafting yield of 15% exhibited higher proton conductivity than commercial Nafion 117 membrane. Likewise, it had better chemical stability than ETFE-g-PSSA membrane prepared by conventional radiation-induced grafting.     

Single Radiation‐Induced Grafting Method for the Preparation of Two Proton‐ and Lithium Ion‐Conducting Membranes

Summary: Two distinct types of polymer electrolyte membranes for conducting protons and lithium ions have been prepared by a radiation‐induced grafting method. The polymer electrolyte precursor (PVDF‐g‐PS) is obtained by the simultaneous grafting of styrene onto poly(vinylidene fluoride) (PVDF) followed by one of two specific treatments. This includes sulfonation with a chlorosulfonic acid/dichloromethane mixture to obtain proton (H⁺)‐conducting membranes, or activation with LiPF₆/EC/DC liquid electrolyte to obtain lithium ion (Li⁺)‐conducting membranes. The chemical structure of the obtained electrolyte membranes is verified by FT‐IR spectroscopy. Differential scanning calorimetry is used to examine the changes in the crystallinity and the thermal properties of both electrolyte membranes during the preparation process. The thermal stability of both electrolyte membranes is also evaluated using thermal gravimetrical analysis. The obtained polymer electrolyte membranes achieve superior conductivity values: 1.61 × 10^?3 S · cm^?1 for Li⁺ and 5.95 × 10^?2 S · cm^?1 for H⁺ at room temperature at a polystyrene content of 50%. The results of this work suggest that high quality H⁺‐ and Li⁺‐conducting membranes can be obtained using a single radiation‐induced grafting method.

Schematic representation of the single root for preparation of Li⁺‐ and H⁺‐conducting membranes started by radiation‐induced grafting of styrene onto a PVDF film followed by chemical treatment.     

Double crosslinked polyetheretherketone-based polymer electrolyte membranes prepared by radiation and thermal crosslinking techniques

Novel one-step preparation of polymer electrolyte membranes without a membrane casting process is achieved by radiation crosslinking of a polyetheretherketone (PEEK) film to prevent dissolution and deformation of the original film in sulfonating solutions. The films crosslinked with doses more than 33 MGy can be effectively sulfonated in a chlorosulfonic solution, resulting in a crosslinked sulfonated PEEK (sPEEK) electrolyte membrane with high proton conductivity comparable to Nafion. Nevertheless, its water uptake was high for application in fuel cells. The thermal treatment was effective for further crosslinking of the membrane; as a result, the water uptake and methanol permeability of the double crosslinked sPEEK membranes drastically decreased, compensating for a slight decrease of proton conductivity. In addition, unlike the traditional cast sPEEK membrane showing the irreversible swelling in hot water, the double crosslinked sPEEK membranes exhibited excellent stability toward 100 °C hot water for more than 200 h without any decrease in proton conductivity, and had the mechanical and thermal properties superior to those of Nafion.     

Effect of composition on the properties of PEM based on polybenzimidazole and poly(vinylidene fluoride) blends

Inadequate performance, short term durability and high cost of polymer electrolyte membrane (PEM) are the major roadblocks that need to be resolved for successful commercialization of high temperature PEM fuel cell. In this report, we investigated the viability of previously developed miscible blend membranes of polybenzimidazole and poly (vinylidene fluoride) (PBI/PVDF), as potential PEMs. In addition, we have carried out several advanced analytical techniques such as dynamic mechanical analysis (DMA), ¹³C CP-MAS solid state NMR (SS-NMR) and wide-angle X-Ray diffraction (WAXD) to prove the miscible behavior of the polymer pair. Sub-ambient temperature DMA studies confirmed the miscible behavior of PBI/PVDF blends at different compositions based on single T_g criterion. SS-NMR and WAXD showed the presence of interactions between the functional groups of the polymers and their dependence on blend composition. Thermogravimetric analysis of phosphoric acid (PA) doped and undoped blend membranes confirmed the improved thermal stability of the membranes compared to neat PBI. The membranes exhibited excellent oxidative stability than pristine PBI membrane. The swelling ratio and volume after dipping in PA was found to be significantly low in the blend membranes owing to the hydrophobic nature of PVDF. Among the blends prepared, 90/10 and 75/25 membranes showed higher proton conductivity than PBI, attributed in part, to electronegativity of fluorine and crystallinity of PBI in PA that activate proton transport. The results demonstrated the potential usefulness of the blend membranes as PEM in fuel cell.     

Properties on novel PVDF‐HFP‐based composite polymer electrolyte with vinyltrimethoxylsilane‐modified ZSM‐5

A kind of novel poly(vinylidene fluoride‐co‐hexafluoropropylene) (PVDF‐HFP)‐based composite polymer electrolyte doped with vinyltrimethoxylsilane (DB171 silane)‐modified ZSM‐5 is prepared by phase inversion method (denoted as M‐ZSM‐5 membrane). Physical and chemical properties of M‐ZSM‐5 membrane are studied by SEM, FTIR, TG‐DSC, EIS, and LSV. The results show that thermal and electrochemical stability can reach 400°C and 5 V, respectively; temperature dependence of ionic conductivity follows Vogel–Tamman–Fulcher relation and ionic conductivity at room temperature is up to 4.2 mS/cm; the interfacial resistance reaches a stable value about 325 Ω after 5 days storage at room temperature, which suggests that it can be potentially suitable as electrolyte in polymer lithium ion battery. POLYM. COMPOS., 2012. © 2012 Society of Plastics Engineers     

Comparative investigations of radiation‐grafted proton‐exchange membranes prepared using single‐step and conventional two‐step radiation‐induced grafting methods

Proton‐exchange membranes containing poly(styrene sulfonic acid) grafts hosted in poly(vinylidene fluoride) (PVDF) films were prepared using two radiation‐induced grafting methods: a single‐step grafting method (SSGM) involving grafting of sodium styrene sulfonate onto electron beam (EB)‐irradiated PVDF films and a conventional two‐step grafting method (CTSGM) in which styrene monomer is grafted onto EB‐irradiated PVDF films and subsequently sulfonated. Differential scanning calorimetry, universal mechanical testing and scanning transmission electron microscopy were used to evaluate the thermal, mechanical and structural changes developed in the membranes during the preparation procedures. Physicochemical properties such as water uptake, hydration number and ionic conductivity were studied as functions of ion‐exchange capacity and the results obtained were correlated with the structural changes accompanying each preparation method. Membranes obtained using the SSGM were found to have superior properties compared to their counterparts prepared using the CTSGM suggesting the former method is more effective than the latter for imparting desired functionality and stability properties to the membranes. Copyright © 2010 Society of Chemical Industry     

Sulfonated graphene oxide‐doped proton conductive membranes based on polymer blends of highly sulfonated poly(ether ether ketone) and sulfonated polybenzimidazole

Simultaneously improving the proton conductivity and mechanical properties of a polymer electrolyte membrane is a considerable challenge in commercializing proton exchange membrane fuel cells. In response, we prepared a new series of miscible polymer blends and thus the corresponding crosslinked membranes based on highly sulfonated poly(ether ether ketone) and sulfonated polybenzimidazole. The blended membranes showed more compact structures, due to the acid‐base interactions between the two constituents, and improved mechanical and morphological properties. Further efforts by doping sulfonated graphene oxide (s‐GO) forming composite membranes led to not only significantly elevated proton conductivity and electrochemical performance, but also better mechanical properties. Notably, the composite membrane with the filler content of 15 wt % exhibited a proton conductivity of 0.217 S cm^?1 at 80 °C, and its maximum power density tested by the H₂/air single PEMFC cell at room temperature reached 171 mW cm^?2, almost two and half folds compared with that of the native membrane. As a result, these polymeric membranes provided new options as proton exchange membranes for fuel‐cell applications. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46547.     

EB‐crosslinked Polymer Electrolyte Membranes Based on Highly Sulfonated Poly(ether ether ketone) and Poly(vinylidene fluoride)/Triallyl Isocyanurate

In this study, crosslinked polymer electrolyte membranes for polymer electrolyte membrane fuel cell (PEMFC) applications are prepared using electron beam irradiation with a mixture of sulfonated poly(ether ether ketone) (SPEEK), poly(vinylidene fluoride) (PVDF), and triallyl isocyanurate (TAIC) at a dose of 300 kGy. The gel‐fraction of the irradiated SPEEK/PVDF/TAIC (95/4.5/0.5) membrane is 87% while the unirradiated membrane completely dissolves in DMAc solvent. In addition, the water uptake of the irradiated membrane is 221% at 70 °C while that of the unirradiated membrane completely dissolves in water at above 70 °C. The ion exchange capacity and proton conductivity of the crosslinked membrane are 1.57 meq g⁻¹, and 4.0 × 10⁻² S cm⁻¹ (at 80 °C and RH 90%), respectively. Furthermore, a morphology study of the membranes is conducted using differential scanning calorimetry and X‐ray diffractometry. The cell performance study with the crosslinked membrane demonstrates that the maximum power density is 518 mW cm⁻² at 1036 mA cm⁻² and the maximum current density at applied voltage of 0.4 V is 1190 mA cm⁻².     

Fabrication and characterization of electrolyte membranes based on organoclay/tripropyleneglycol diacrylate/poly(vinylidene fluoride) electrospun nanofiber composites

Utilizing polymer electrospinning technology, novel electrolyte membranes based on poly(vinylidene fluoride) (PVDF)/organomodified clay (OC)/tripropyleneglycol diacrylate (TPGDA) composite nanofibers with a diameter of 100–400 nm were fabricated for application in lithium batteries. Ultraviolet photo‐polymerization of electrospun PVDF/OC/TPGDA nanofibers generated chemically crosslinked TPGDA‐grafted PVDF/OC nanofibers exhibiting robust mechanical and electrochemical properties. The prepared fibrous PVDF/OC/TPGDA electrolytes were characterized in terms of morphology, crystallinity, electrochemical stability, ionic conductivity and cell cycleability. Based on differential scanning calorimetry analysis, the crystallinity of PVDF decreased by ca 10% on employing the OC and TPGDA. Compared with pure PVDF film‐based electrolyte membranes, the TPGDA‐ and OC‐modified PVDF electrolyte membranes exhibited improved mechanical properties and various electrochemical properties. The OC‐ and TPGDA‐modified microporous membranes are promising candidates for overcoming the drawbacks of the lower mechanical stability of fibrous‐type electrolytes with further improvement of electrochemical performance. Copyright © 2009 Society of Chemical Industry     

Preparation and characterization of phosphoric acid composite membrane by radiation induced grafting of 4‐vinylpyridine onto poly(ethylene‐co‐tetrafluoroethylene) followed by phosphoric acid doping

Preparation of phosphoric acid composite membranes by radiation induced grafting of 4‐vinylpyridine (4‐VP) onto electron beam irradiated poly(ethylene‐co‐tetrafluoroethylene) film followed by phosphoric acid doping was investigated. The effect of grafting parameters (monomer concentration, absorbed dose, reaction time, and temperature) on the degree of grafting (G%) in the membrane precursor and its relation with the amount of acid doped was studied. The proton conductivity of the obtained membranes was evaluated in correlation with G% and temperature using ac impedance. Fourier transform infrared, thermal gravimetric analysis, X‐ray diffraction, and universal mechanical tester were used to investigate chemical composition, thermal resistance, structure, and mechanical properties of the membranes, respectively. The membranes of 34 and 49% recorded high proton conductivity in the magnitude of 10^‐2 S cm^‐1 without humidification. The membranes were also found to have reasonable mechanical integrity together with thermal stability up to 160°C. The obtained membranes are suggested to be less‐water dependent and have potential for testing in high temperature polymer electrolyte membrane fuel cell. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Salt‐leaching technique for the synthesis of porous poly(2,5‐benzimidazole) (ABPBI) membranes for fuel cell application

The first instance of synthesizing porous poly(2,5‐benzimidazole) (ABPBI) membranes for high‐temperature polymer electrolyte membrane fuel cells (HT‐PEMFCs), using solvent evaporation/salt‐leaching technique, is reported herein. Various ratios of sodium chloride/ABPBI were dissolved in methanesulfonic acid and cast into membranes by solvent evaporation, followed by porogen (salt) leaching by water washing. The membranes were characterized using SEM, FTIR, TGA, and DSC. The proton conductivity, water and acid uptake of the membranes were measured and the chemical stability was determined by Fenton's test. SEM images revealed strong dependence of sizes and shapes of pores on the salt/polymer ratios. Surface porosities of membranes were estimated with Nis Elements‐D software; bulk porosities were measured by the fluid resaturation method. Thermogravimetric analysis showed enhanced dopant uptake with introduction of porosity, without the thermal stability of the membrane compromised. Incorporating pores enhanced solvent uptake and retention because of capillarity effects, enhancing proton conductivities of PEMs. Upon acid doping, a maximum conductivity of 0.0181 S/cm was achieved at 130 °C for a porous membrane compared with 0.0022 S/cm for the dense ABPBI membrane at the same temperature. Results indicated that with judicious optimization of porogen/polymer ratios, porous ABPBI membranes formed by salt‐leaching could be suitably used in HT‐PEMFCs. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 45773.     

A synthesis study of phosphonated PSEBS for high temperature proton exchange membrane fuel cells

A series of novel phosphonated proton exchange membranes has been prepared using poly(styrene‐ethylene/butylene‐styrene) block copolymer (PSEBS) as base material. Phosphonic acid functionalization of the polymer was performed by a simple two‐step process, via chloromethylation of PSEBS followed by phosphonation utilizing the Michaels–Arbuzov reaction. The successful phosphonation of the polymers were characterized by NMR and Fourier transform infrared. The phosphonated ester form of the membranes were obtained by solvent evaporation method and hydrolyzed to get a proton conducting membrane. The membrane properties such as ion exchange capacity, water uptake and proton conductivity at various temperatures were examined for their suitability to be utilized as a high temperature polymer electrolyte. Additionally, the morphology, thermal, and mechanical properties of the synthesized membranes were investigated, using scanning electron microscope, thermogravimetric analysis, and tensile test, respectively. The effective (anhydrous) proton conductivity was studied with respect to various degrees of functionalization. From the studies, the membranes were found to have a comparatively good conductivity and one of the membranes reached the maximum value of 5.81 mS/cm² at 140 °C as measured by impedance analyzer. It was found that the synthesized membranes were mechanically durable, chemically, and thermally stable. Hence, the synthesized phosphonated membranes could be a promising candidate for high temperature polymer electrolyte fuel cell applications. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 45954.     

Cell performances of direct methanol fuel cells with grafted membranes

Cell performances were evaluated with grafted polymer membranes as an electrolyte for a direct methanol fuel cell (DMFC). The membranes were prepared using a poly(ethylene-tetrafluoroethylene), or ETFE, film. The base polymer film was added to sulfonic groups using γ-radiation activated grafting technique as ion-exchange groups. These membranes had more suitable properties for DMFCs, i.e. higher electric conductivity and lower methanol permeability than perfluorinated ionomer membrane (Nafion). Nevertheless, the cell performance with the grafted membrane was inferior to that with Nafion. The analysis of electrode potentials vs. reversible hydrogen electrode showed larger activation overpotential for both the electrodes on the grafted membranes. We concluded that this is due to poor bonding of the catalyst layers to the grafted membranes.     

Preparation and characterization of proton exchange membrane based on polyphosphoric acid modified by PVDF‐HFP

A polyphosphoric acid functionalized proton exchange membrane (PEM) was prepared by a ring opening reaction using the epoxycyclohexylethyltrimethoxysilane (EHTMS) and amino trimethylene phosphonic acid (ATMP) as raw materials and was modified by poly(vinylidene fluoride)–hexafluoro propylene (PVDF‐HFP). The structure of the membranes was characterized by Fourier transform infrared and scanning electron microscopy. The X‐ray photoelectron spectroscopy explores the content of the elements in the membrane related to the ion exchange capacity value. The membranes’ properties including water uptake, swelling ratio, proton conductivity, and hydrolysis stability were studied. Performance tests show that when ATMP/EHTMS = 1/5, conductivity of the PVDF‐HFP modified PEMs increased from 0.83 × 10^?4 S cm^?1 at 20 °C to 9.53 × 10^?3 S cm^?1 at 160 °C, the swelling ratio of membranes decreased from 2.71% to 2.13%. The results indicate that the introduction of F atoms is beneficial to increase the proton conductivity and the dimensional stability. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46737.     

Shape stability enhancement of PVDF electrospun polymer electrolyte membranes blended with poly(2-acrylamido-2-methylpropanesulfonic acid lithium)

The purpose of this study is to overcome the poor dimensional stability of poly(vinylidene fluoride) (PVDF)-based electrospun membranes for polymer electrolytes, a new type of composite fibrous membranes based on PVDF/poly(2-acrylamido-2-methylpropanesulfonic acid lithium) (PAMPSLi) blend systems with different blend ratios were fabricated by electrospinning method. Morphology of the composite fibrous membranes was evaluated by scanning electron microscopy. Average diameters of the membranes were less than 250 nm, which were far less than that of pure PVDF fibrous membrane (400 nm). Fourier transform infrared spectroscopy and Raman scattering were used to characterize the interactions of two polymers. Wide-angle X-ray diffraction and differential scanning calorimetry techniques were applied to investigate the crystal structure of composite fibrous membranes. Owning to the good miscibility between PVDF and PAMPSLi, no phase-separated microstructure was observed in composite fibrous membranes. The membranes possessed a good wettability by liquid electrolytes and exhibited an excellent dimensional stability even at high loading of electrolytes. The polymer electrolyte showed the ionic conductivity of 3.45 × 10^?3 S/cm at room temperature and electrochemical stability up to 5.4 V for the blend ratio of 5/1. PVDF/PAMPSLi (5/1)-based polymer electrolyte was observed much more suitable than polymer electrolytes with other ratios of PVDF/PAMPSLi for application in high-performance lithium rechargeable batteries.