Novel membranes based on poly(5‐(methacrylamido)tetrazole) and sulfonated polysulfone for proton exchange membrane fuel cells

Proton‐exchange membrane fuel cells (PEMFC)s are increasingly regarded as promising environmentally benign power sources. Heterocyclic molecules are commonly used in the proton conducting membranes as dopant or polymer side group due to their high proton transfer ability. In this study, 5‐(methacrylamido)tetrazole monomer, prepared by the reaction of methacryloyl chloride with 5‐aminotetrazole, was polymerized via conventional free radical mechanism to achieve poly(5‐(methacrylamido)tetrazole) homopolymer. Novel composite membranes, SPSU‐PMTetX, were successfully produced by incorporating sulfonated polysulfone (SPSU) into poly(5‐(methacrylamido)tetrazole) (PMTet). The sulfonation of polysulfone was performed with trimethylsilyl chlorosulfonate and high degree of sulfonation (140%) was obtained. The homopolymers and composite membranes have been characterized by NMR, FTIR, thermogravimetric analysis (TGA), and differential scanning calorimetry (DSC). ¹H‐NMR and FTIR confirmed the sulfonation of PSU and the ionic interaction between sulfonic acid and poly(5‐(methacrylamido)tetrazole) units. TGA showed that the polymer electrolyte membranes are thermally stable up to ～190°C. Scanning electron microscopy analysis indicated the homogeneity of the membranes. This result was also supported by the appearance of a single T_g in the DSC curves of the blends. Water uptake and proton conductivity measurements were, as well, carried out. Methanol permeability measurements showed that the composite membranes have similar methanol permeability values with Nafion 112. The maximum proton conductivity of anhydrous SPSU‐PMTet0.5 at 150°C was determined as 2.2 × 10^?6 S cm^?1 while in humidified conditions at 20°C a value of 6 × 10^?3 S cm^?1 was found for SPSU‐PMTet2. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40107.     

Solid polymer electrolyte based on waterborne polyurethane for all‐solid‐state lithium ion batteries

A series of solid polymer electrolytes (SPEs) based on comb‐like nonionic waterborne polyurethane (NWPU) and LiClO₄ are fabricated via a solvent free process. The NWPU‐based SPEs have sufficient mechanical strength which is beneficial to their dimensional stability. Differential scanning calorimetry analysis indicates that the phase separation occurs by the addition of the lithium salt. Scanning electron microscopy and X‐ray diffraction analyses illustrate the good compatibility between LiClO₄ and NWPU. Fourier transform infrared study reveals the complicated interactions among lithium ions with the amide, carbonyl and ether groups in such SPEs. AC impedance spectroscopy shows the conductivity of the SPEs exhibiting a linear Arrhenius relationship with temperature. The ionic conductivity of the SPE with the mass content of 15% LiClO₄ (SPE15) can reach 5.44 × 10^?6 S cm^?1 at 40 °C and 2.35 ×10^?3 S cm^?1 at 140 °C. The SPE15 possesses a wide electrochemical stability window of 0–5 V (vs. Li+/Li) and thermal stability at 140 °C. The excellent properties of this new NWPU‐based SPE are a promising solid electrolyte candidate for all‐solid‐state lithium ion batteries. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134 , 45554.     

Effects of ultrasonic assisted processing and clay nanofiller on dielectric properties and lithium ion transport mechanism of poly(methyl methacrylate) based plasticized polymer electrolytes

Lithium ion conducting solid polymer electrolyte (SPE) films consisted of poly(methyl methacrylate) (PMMA) matrix with lithium perchlorate as a dopant ionic salt, poly(ethylene glycol) as plasticizer and montmorillonite clay as inorganic nanofiller have been prepared by classical solution casting and high intensity ultrasonic assisted solution casting methods. The X‐ray diffraction study confirmed the amorphous structure of all these PMMA‐based solid electrolytes and the clay nanosheets existed in exfoliated form in their amorphous phase. Dielectric relaxation spectroscopy had been employed for the investigation of complex dielectric function, ac electrical conductivity, electric modulus, and impedance spectra of these electrolytes over the frequency range from 20 Hz to 1 MHz. It was observed that the dielectric properties and ionic conductivity of the electrolytes strongly depended on the sample preparation methods, and also had changes with addition of the clay nanofiller. Temperature‐dependent dielectric study of the electrolyte films confirmed that their dc ionic conductivity and conductivity relaxation time values obeyed the Arrhenius behavior. This study also revealed that the lithium ion transportation in the ion–dipolar complexes of these electrolytes occurred through hopping mechanism and it was correlated with the conductivity relaxation time. Preparation of these electrolyte films through ultrasonic assisted solution casting method increased the ionic conductivity by more than one order of magnitude in comparison to that of the classical solution casting method, which revealed that the former was a novel method for the preparation of these SPEs of relatively enhanced ionic conductivity. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42188.     

Oligomeric A2 + B3 synthesis of highly branched polysulfone ionomers: novel candidates for ionic polymer transducers

Highly branched poly(arylene ether sulfone)s with systematically varied degrees of branching and sulfonation were synthesized through oligomeric A₂ + B₃ methods for application as ionic polymer transducer (IPT) membranes. IPTs are a class of electroactive polymer devices that leverage ionomeric membranes to perform electromechanical transduction as actuators and/or sensors. Synthesis of controlled molecular weight A₂ oligomeric polysulfones targeted the global degree of branching (DB_global) to approximately 1–3% in the absence of gelation. Size exclusion chromatography confirmed molecular weights greater than 20 000 g mol^?1 were achieved for linear and branched polysulfones. Increased degree of sulfonation of the A₂ oligomers reduced the development of molecular weight in the oligomeric A₂ + B₃ branching reaction; the formation of tough, flexible, ion‐conducting membranes is required for emerging transducer applications. Variation in the DB_global attained did not affect the thermal transitions or elastic modulus as significantly as changes in the degree of sulfonation. However, an ionic dissociation temperature was detected below the glass transition temperature of the polysulfone matrix and was relatively independent of the degree of sulfonation. Successful synthesis and characterization of these well‐defined branched polysulfone ionomers provide a basis for future investigation of polymer topology effects on IPT performance. Copyright © 2009 Society of Chemical Industry     

Studies on electrochemical properties of poly (ethylene oxide)-based gel polymer electrolytes with the effect of chitosan for lithium–sulfur batteries

Composite gel polymer electrolytes (CGPE), with different proportions of poly (ethylene oxide), plasticizers namely 1,3-dioxolane (DIOX)/tetraethelyneglygol dimethylether (TEGDME) and a lithium salt (LITFSI) with the addition of filler chitosan were prepared using the solution casting technique in an argon atmosphere. The membranes were subjected to various characterization techniques such as TG/DTA, FTIR and an ac impedance analysis. A lithium symmetric cell (Li/CGPE/Li) was assembled and the interfacial stability of the polymer electrolyte with a lithium anode was measured. The electrochemical stability and the transport properties of the high conducting sample were also measured. TG/DTA shows the thermal stability of the high conducting sample. The optimal value of the plasticizers was to be found in the ionic conductivity point of view.     

聚缩水甘油苄基醚磺酸三乙醇胺盐的合成与表征

本文采用叔丁基锂引发缩水甘油苄基醚聚合,得到不同分子量的聚缩水甘油苄基醚预聚体(PBzGELi),再以氯磺酸磺化,三乙醇胺中和得到了不同磺化度的聚缩水甘油苄基醚磺酸三乙醇胺盐(SPBzGETEA)。结合VPO,NMR,FTIR等分析手段对每步产物的结构进行了详细的表征。结果表明:聚合得到的PBzGELi分子量一般在1000～4000,聚合机理符合末端立构聚合模型;所得聚缩水甘油苄基醚磺酸的平均磺化度在300以上,其苯环的邻,间,对位取代反应活性相差不大;得到的聚缩水甘油苄基醚磺酸三乙醇胺盐为离子液体功能高分子。     

Design and synthesis of ionic-conductive epoxy-based networked polymers

To develop ionic-conductive film-shaped electrolytes with high reliability, we designed and synthesized the following networked polymers with an epoxy/amine curing system using poly(ethylene glycol) as the main skeleton, and examined their fundamental properties such as ionic conductivity, thermal stability, and inflammability. (1) Networked polymers having quaternary ammonium salt structures. (2) Networked polymers having lithium sulfonate salt structures. (3) Networked polymers having lithium sulfonylimide salt structures. (4) Networked polymers swollen with ionic liquid solutions of lithium salts. Consequently, we found that networked polymers swollen with ionic liquid solutions containing lithium salts showed high ionic conductivity and high thermal stability with excellent non-flammability.     

Synthesis of microphase‐separated solvent‐free solid polymer electrolyte nanocomposite films using amphiphilic urethane acrylate precursors

A new solvent‐free solid polymer electrolyte (SPE) films could be fabricated through bulk copolymerization process of amphiphilic urethane acrylate nonionomer (UAN). Amphiphilic UAN chain having polypropylene oxide‐based hydrophobic segment and polyethylene oxide‐based hydrophilic segment can not only dissolve lithium salt by complex formation with lithium cations but also be copolymerized with various monomers to form microphase‐separated polymeric matrix. Unlike conventional SPE systems showing higher conductivity with polar polymers and polar solvents, our SPE films prepared by copolymerization of UAN and hydrophobic monomers exhibited relatively higher conductivity. Dissolving lithium salts in UAN/hydrophobic monomer mixtures caused hydrophilic/hydrophobic microphase separation, which was more favorable for ionic conduction of lithium ions, resulting in the higher ionic conductivity than the SPE films fabricated using UAN/hydrophobic monomer mixture. This microphase‐separated structure of SPE films could be also confirmed by transmission electron microscope (TEM) images. Ionic conductivity of our SPE films could be also improved by dispersing clay minerals within SPE films. Three types of clay having different surface properties were used to fabricate clay/SPE nanocomposite films. Ionic conductivity of nanocomposite films depended on dispersibliity of clay nanoparticles with a SPE film, which was confirmed by measuring X‐ray diffraction and TEM. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007     

Fabrication and properties of crosslinked poly(propylene carbonate maleate) gel polymer electrolyte for lithium‐ion battery

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 T_g 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/LiNi_1/3Co_1/3Mn_1/3O₂ 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/LiNi_1/3Co_1/3Mn_1/3 O₂ cell is 115.3 mAh g⁻¹. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Sulfonated poly(arylene ether sulfone)/Laponite-SO3H composite membrane for direct methanol fuel cell

Polymer nanocomposite membranes based on sulfonated poly(arylene ether sulfonate) (SPAES) containing a flake filler (Laponite) with varying degrees of sulfonation, were prepared and characterized for application in direct methanol fuel cells (DMFCs). Unlike most other clays, Laponite crystals are very small in size with a very low aspect ratio (diameter to thickness ratio) of 25–30. They improve the mechanical, thermal properties and decreased the fuel permeability. However, polymer composite membranes containing non-proton conducting inorganic particles tend to show low proton conductivity, as compared with pristine polymer membranes. To resolve this problem, prior to the preparation of the composite membranes, Laponite-Na+(NLa) was sulfonated with various amounts of organo silanes (3-Mercaptopropyl trimethoxysilane (SH-silane)) via an ion exchange method. Functionalized Laponite with the organic silane compound showed higher ion exchange capacity and ion conductivity, respectively. In order to minimize the loss of proton conductivity while reducing the methanol permeability, various amounts (0.5–2.0 wt%) of the organically sulfonated Laponite (SLa) were introduced into the SPAES matrices. The performances of hybrid membranes for DMFCs in terms of mechanical properties, behavior of water in membranes, proton conductivity and methanol permeability were investigated.     

Decoupled ion conduction mechanism of poly(vinyl alcohol) based Mg-conducting solid polymer electrolyte

Investigation on solid state rechargeable magnesium batteries are considered important similar to lithium batteries. In view of negligible hazard and less reactivity of the magnesium, in comparison with lithium, studies on rechargeable magnesium batteries are expected to have a wide scope in future. In the present investigations, decoupled ion conduction of poly(vinyl alcohol) (PVA)-based Mg-conducting solid polymer electrolytes (SPEs) is essential component of the studies. In common SPEs, ion transport has mostly been associated with the segmental motion of the polymer, so significant conductivity is only observed above the glass transition temperature of the system. But the results of ac impedance spectroscopy, FT-IR, XRD and AFM indicated that prepared PVA-based Mg-conducting SPE shows ionic transport decoupled from polymer segmental motion and high ionic conductivity at room temperature.     

Bifunctional poly(ethylene glycol) based crosslinked network polymers as electrolytes for all‐solid‐state lithium ion batteries

Polymer electrolyte based lithium ion batteries represent a revolution in the battery community due to their intrinsic enhanced safety, and as a result polymer electrolytes have been proposed as a replacement for conventional liquid electrolytes. Herein, the preparation of a family of crosslinked network polymers as electrolytes via the ‘click‐chemistry’ technique involving thiol‐ene or thiol‐epoxy is reported. These network polymer electrolytes comprise bifunctional poly(ethylene glycol) as the lithium ion solvating polymer, pentaerythritol tetrakis (3‐mercaptopropionate) as the crosslinker and lithium bis(trifluoromethane)sulfonimide as the lithium salt. The crosslinked network polymer electrolytes obtained show low T_g, high ionic conductivity and a good lithium ion transference number (ca 0.56). In addition, the membrane demonstrated sterling mechanical robustness and high thermal stability. The advantages of the network polymer electrolytes in this study are their harmonious characteristics as solid electrolytes and the potential adaptability to improve performance by combining with inorganic fillers, ionic liquids or other materials. In addition, the simple formation of the network structures without high temperatures or light irradiation has enabled the practical large‐area fabrication and in situ fabrication on cathode electrodes. As a preliminary study, the prepared crosslinked network polymer materials were used as solid electrolytes in the elaboration of all‐solid‐state lithium metal battery prototypes with moderate charge–discharge profiles at different current densities leaving a good platform for further improvement. © 2018 Society of Chemical Industry     

光聚合PEO体系高分子固体电解质膜的制备及其性能

引　言由极性聚合物 -碱金属盐络合而成的高分子固体电解质 (ＳＰＥ)是一类很有前途的离子导电材料 ,除具备一般固体电解质的性能外 ,还具有质轻、黏弹性好、易成膜等独特的优点 ,尤其适合作为全固高能密度聚合物电池的电解质材料 ,从而给电源领域引入了电池技术的全新概念 .欲使高分子固体电解质材料实用化 ,必须解决高分子固体电解质薄膜的合成问题 .通常采用的成型方法如溶剂法、热熔法等或者消耗溶剂 ,或者需要基材加热 ,造成高生产成本和低生产效率 ,而且由于有机溶剂的挥发 ,又带来了电池工业环境污染问题[1] .本文针对高氯酸锂 -聚氧…     

Synthesis, structure characterization and ionic conductivity of star-branched organic-inorganic hybrid electrolytes based on cyanuric chloride, diamine-capped poly(oxyalkylene) and alkoxysilane

A synthesis route for preparing highly conductive solid organic-inorganic hybrid electrolytes has been developed by using cyanuric chloride as the coupling core to react with diamino-terminated poly(oxyalkylene) triblock copolymers, followed by cross-linking with an epoxy alkoxysilane 3-glycidyloxypropyl trimethoxysilane via a sol-gel process. The present hybrid electrolyte with a [O]/[Li] ratio of 32 was found to be the most conductive, reaching a maximum lithium ion conductivity of 6.8 × 10⁻⁵ Scm⁻¹ at 30 °C. The Li-ion mobility was determined from ⁷Li static NMR line width measurements and correlated with their ionic conductivities. The onset of ⁷Li line narrowing was closely related to the T_g of the hybrid electrolytes as measured by DSC experiments. Thus, the motions of the lithium cations are strongly coupled with the segmental motion of the polymer chains, which is in line with the Vogel-Tamman-Fulcher behavior as observed in ionic conductivity.     

Electrospun poly(lithium 2‐acrylamido‐2‐methylpropanesulfonic acid) fiber‐based polymer electrolytes for lithium‐ion batteries

Novel single‐ion conducting polymer electrolytes based on electrospun poly(lithium 2‐acrylamido‐2‐methylpropanesulfonic acid) (PAMPSLi) membranes were prepared for lithium‐ion batteries. The preparation started with the synthesis of polymeric lithium salt PAMPSLi by free‐radical polymerization of 2‐acrylamido‐2‐methylpropanesulfonic acid, followed by ion‐exchange of H⁺ with Li⁺. Then, the electrospun PAMPSLi membranes were prepared by electrospinning technology, and the resultant PAMPSLi fiber‐based polymer electrolytes were fabricated by immersing the electrospun membranes into a plasticizer composed of ethylene carbonate and dimethyl carbonate. PAMPSLi exhibited high thermal stability and its decomposition did not occur until 304°C. The specific surface area of the electrospun PAMPSLi membranes was raised from 9.9 m²/g to 19.5 m²/g by varying the solvent composition of polymer solutions. The ionic conductivity of the resultant PAMPSLi fiber‐based polymer electrolytes at 20°C increased from 0.815 × 10^?5 S/cm to 2.12 × 10^?5 S/cm with the increase of the specific surface area. The polymer electrolytes exhibited good dimensional stability and electrochemical stability up to 4.4 V vs. Li⁺/Li. These results show that the PAMPSLi fiber‐based polymer electrolytes are promising materials for lithium‐ion batteries. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Charge cycling and impedance characterization of a polyphosphazene solid polymer electrolyte-manganese(IV) oxide intercalation cathode

The compatibility of polyphosphazene (PPZ) polymer electrolytes with MnO₂/C/SPE intercalation cathodes (IC) was investigated. Three-layered laminates of a phosphazene-based solid polymer electrolyte (SPE) film sandwiched between two MnO₂-based ICs (one preloaded with lithium) were constructed. The cathodes were fabricated by either solvent casting or compression techniques. Two different crystal forms of manganese(IV) oxide—λ-MnO₂ and γ-MnO₂—were employed, together with methoxy ethoxy ethoxy PPZ (MEEP) SPE binder material. Carbon black was employed as the electronically conductive phase. One cathode in each laminate was prepared in the ‘chemically intercalated’ form by using LiMn₂O₄ in place of MnO₂. The podand polymer, SMEP, which has better thin film mechanical properties than does MEEP, was complexed with lithium trifluoromethane sulfonate (Li triflate) and used as the SPE. Li⁺ ions were cycled galvanostatically between the two-ICs, through the phosphazene-based SPE layer. The performance of the cell was continuously monitored by electrochemical impedance spectroscopy (EIS) and by measuring the laminate thickness and voltage drop. The method of cathode fabrication (casting vs. pressing) was found to be the primary factor influencing the cycle life.     

Synthesis and properties of heptadecane-functionalized poly(propylene oxide) based single-ion polymer electrolytes

Lithium methacrylate and heptadecane-functionalized poly(propylene oxide) (PPO) methacrylate based single-ion polymer electrolytes have been synthesized by radical copolymerization and neutralization. The thermal and electrical properties of the polymer electrolyte have been characterized by differential scanning calorimetry (DSC) and AC impedance spectroscopy, respectively. The results showed that the crystalline melting behavior of PPO segment was changed significantly by the presence of lithium ion due to the coordinative interaction and enhanced crystallinity. The ionic conductivity was 1.8 × 10^?7 S cm^?1 at 25 °C in the case of the lithium ion concentration of [PO]:[Li] = 30:1 due to the single-ion nature but its transference number reached roughly 1, indicating no migration of counter anions. Inspection with control sample suggested that the polymer electrolyte with ion conduction channel formed by a self-assembly is favored to realize relatively high ionic conductivity and decoupled lithium ion motion. The contact angle measurement onto the polymer electrolyte surface showed a strong hydrophobic wetting behavior due to the integrated hydrophobic nature of PPO and heptadecane alkyl chains.     

A new series of cross-linked (meth)acrylate polymer electrolytes for energy storage

A series of methacrylate-crosslinked polymers were investigated as potential polymer electrolytes for energy storage application. Methacrylate ester crosslinkers (25–50 mol.%) with different spacer lengths and MMA as comonomer were polymerised into thin films. Mixtures of ethylene carbonate and propylene carbonate (EC/PC) or alternatively the ionic liquid 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide (EMIM TFSI), both doped with lithium bis(trifluoromethane)sulfonimide (LiTFSI), fulfilled the role of electrolyte and porogen simultaneously. Ionic conductivity increased with increasing porogen content, Li ion concentration, and decreasing amounts of crosslinker (maximum values: 0.5 mS/cm (EC/PC) and 4.5 mS/cm (EMIM TFSI)). Thin films with permanent porosity were obtained for both electrolyte systems. The flexibility of the films increased with a lower concentration of crosslinker or the choice of a crosslinker with a longer spacer. The relationship between pore size, pore morphology, glass transition temperature and ionic conductivity on the other hand was complex and did not exhibit distinct trends. High thermal stability, ionic conductivity and tunable mechanical properties make these polymer thin films attractive candidates as in situ filled Li ion battery separator films either preformed or directly printed.     

紫外光交联法制备全固态聚合物电解质

制约全固态聚合物电解质开发应用的瓶颈在于如何同时实现高离子电导率与高机械强度。采用可逆加成断裂链转移（RAFT）溶液聚合技术,以3-环己烯-1-亚甲基丙烯酸酯（CEA）为后交联单体,聚乙二醇甲醚丙烯酸酯（PEGMA）为导离子单体,制备了不同链结构的全固态聚合物电解质,再通过硫醇-烯烃之间的“点击化学”反应形成化学交联网络结构。所制备的三嵌段共聚物电解质具有独立的导离子中间嵌段,且交联单体位于分子链两端,从而能够同时满足离子电导率与机械强度的要求。该三嵌段共聚物电解质在60℃下的离子电导率为6.13×10^-5 S/cm,并应用于磷酸亚铁锂/锂（LiFePO₄/Li）全固态电池。所得电池在0.5 C下循环130圈后,放电比容量为139.1 mAh/g,容量保持率为97.8%,库仑效率高于99.0%,显示出良好的电化学性能。     

Electrochemical studies on composite gel polymer electrolytes for lithium sulfur‐batteries

Poly(ethylene oxide)‐based composite gel polymer electrolytes (CGPE's) were prepared for various concentrations of magnesium aluminate (MgAl₂O₄) and LiTFSI as salt with a combination of 1,3‐dioxolane (DOL) and tetraethylene glycol dimethyl ether (TEGDME) as plasticizer by a simple solution casting technique. The addition of plasticizers has significantly improved the ionic conductivity of the gel electrolytes. The prepared CGPEs were subjected to scanning electron microscopy, thermal, and FT‐IR analysis. The electrochemical properties such as ionic conductivity, compatibility, and charge–discharge behavior have also been studied. Preliminary studies revealed that the prepared CGPE can be employed as a potential electrolyte for lithium–sulfur (Li–S) batteries. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 44594.