Conducting Polymer Electrolyte Membranes Research Articles

Fundamental insights into structure-performance relationship for proton conductivity enhancement through polymer electrolyte membrane in Proton Exchange Membrane Fuel Cell

The efficiency of a polymer electrolyte membrane fuel cell (PEMFC) is limited by the proton conductivity of polymer electrolyte membrane (PEM). Local structural variation with hydrophobic-hydrophilic zone segregation in PEM affects proton conductivity profoundly. There is a lack of elemental theoretical model to predict proton transport in novel PEMs with a wide range of compositions and structures. In this work, the first-principle based meso-scale modelling has been attempted to address localised structural variations. The membrane is divided into repetitive lattice of uniform structure. The segregated domains follow periodic or random arrangements. The applicable governing equations are solved numerically under appropriate boundary conditions. The system parameters are recognized and their effects are thoroughly investigated. For the futuristic PEMs, the effect of variation in zone arrangement, its size and its gradual change was investigated. The model was validated with reported data of Nafion membranes with successful prediction of conductivity at different operating temperature and humidity. A phase-space plot was generated for use as a straight-forward tool for prediction of proton conductivity at different operating environment for varying segregation level. The developed model can enlighten the transport mechanism through any existing and futuristic PEMs, scale-up and design them according to the application requirement.

Highly conductive and mechanically robust single-ion conducting polymer electrolyte membranes with a high concentration of charge carriers for dendrite-proof lithium metal batteries

Single-ion polymer electrolytes (SIPEs) with high Li-ion transference number (tLi+≈1) are promising candidates for inhibiting the growth of lithium dendrites in lithium metal batteries (LMBs). However, it remains challenging to develop SIPEs applicable to high-performance LMBs due to their relatively low ionic conductivity and poor mechanical strength. Herein, an aromatic single-ion conductor (LiPSBI) with high Li-ion concentration is elaborately designed, yielding porous and mechanically robust SIPE membranes (NSIPM) when mixed with aliphatic poly (vinylidene fluoride-hexafluoropropylene) P(VDF-HFP) binder via “structural self-assembly” method. As expected, the as-prepared NSIPM porous membranes can simultaneously exhibit a high porosity of 41.4%, a considerable organic solvent uptake of 181.0%, and excellent mechanical strength of 20.5 MPa. Notably, the LiPSBI-based gel NSIPM demonstrates an ionic conductivity of 8.15 × 10−5 S cm−1 at 25 °C, which is almost twice that of the single-ion electrolyte with low Li-ion concentration (4.74 × 10−5 S cm−1). Consequently, the Li||LiFePO4 cells using the gel NSIPM display remarkable cycling durability for several hundred cycles while delivering high discharge specific capacities of 148.4 mA h g−1 and 122.9 mA h g−1 at 0.2C and 1 C, respectively. In addition, the Li/Li symmetric cells assembling the gel NSIPM can effectively alleviate concentration polarization and inhibit the lithium dendrites growth, which is responsible for an exceptionally steady striping/plating process with a low overpotential over 1300 h at 2.5 mA cm−1 at 25 °C. This work provides a new strategy to prepare high-performance SIPEs by increasing the concentration of charge carriers.

Zwitterion-doped self-supporting single-ion conducting polymer electrolyte membrane for dendrite-free lithium metal secondary batteries

Zwitterion-doped self-supporting single-ion conducting polymer electrolyte membrane for dendrite-free lithium metal secondary batteries

Proton conductivity and dimensional stability of proton exchange membrane: A dilemma solved by chitosan aerogel framework

Increasing proton conductivity of polymer electrolyte membrane (PEM) by introducing more number of proton transfer species, especially sulfonated groups always lead to a decrease in mechanical/dimensional stability. The present work proposes the solution to overcome this dilemma by applying chitosan (CS) interconnected with sulfonated poly(ether ether ketone) (SPEEK) to provide not only the 3D framework for dimensional stability but also the sulfonated groups and amino groups play the role in proton transfer. By simply crosslinking CS with succinic acid (SA) followed by lyophilizing, the stable 3D-framework (CS-x)-SA can be obtained. This (CS-x)-SA framework allows the incorporation of SPEEK during membrane formation results in semi-interpenetrating (CS-x)-SA-SPEEK. The (CS-0.25)-SA-SPEEK membrane obtained performs mechanical stability in terms of tensile strength for 12%, with a proton conductivity increment for 34% as compared to SPEEK. The present work demonstrates an approach to achieve the 3D interconnected composite PEM to achieve the improvement in proton transfer efficiency and mechanical strength as well as dimensional stability.

Development and characterization of eco-friendly biopolymer gellan gum based electrolyte for electrochemical application

Abstract Magnesium ion conducting eco-friendly biopolymer electrolyte based on gellan gum has been developed by solution casting technique and characterized by XRD, FTIR, DSC, AC impedance analysis and LSV. Amorphous nature of the polymer electrolyte has been confirmed by XRD analysis. FTIR analysis confirms the complex formation between gellan gum and magnesium nitrate salt. Glass transition temperature of the polymer electrolytes have been found in DSC analysis. Ionic conductivity of polymer electrolyte membrane has been analysized by AC impedance studies, polymer electrolyte 1.0 g gellan gum with 0.7 wt% Mg (NO3)2 has highest ionic conductivity 1.392 × 10−2 S/cm at room temperature. Evan’s polarization method attributes Mg+ cationic transference number as 0.342 for high conducting polymer electrolyte. The high conducting polymer membrane has electrochemical stability 3.58 V. Using this high conducting polymer electrolyte, magnesium ion battery is constructed and the battery performance was studied. The open circuit voltage is found as 1.99 V.

Mechanically robust and highly conductive polymer electrolyte membranes comprising high molecular weight poly[2,2′-(bipyridyl)-bibenzimidazole] and graphene oxide

Promising proton exchange membranes comprising a nitrogen-rich and a high molecular weight poly[2,2′-(bipyridyl)-bibenzimidazole] (BipyPBI) polymer as a substrate and graphene oxide (GO) as a filler were successfully fabricated. The synergism of GO on the membrane physicochemical properties, including the acid doping level, acid retention capability, water uptake, swelling degree, mechanical properties, proton conductivity, oxidative stability, and the hydrogen permeability was studied. The results of the study confirmed the fabrication of mechanically robust and highly conductive proton exchange membranes. Regarding the phosphoric acid (PA) doping level, the BipyPBI/GO membrane reached 17 mol of PA per monomeric unit of BipyPBI (an increase of around 69% in PA-doping level compared to the bare BipyPBI membrane). The proton conductivity at 60 °C under anhydrous conditions increased from 0.002 S cm−1 to 0.019 S cm−1 (around 10-folds increase) when 4 wt% of GO was incorporated into the BipyPBI matrix. In addition, the conductivity reached 0.045 S cm−1 at 140 °C. The activation energy of the proton conduction decreased from 45.6 kJ mol−1 for the bare BiPyPBI to 12 kJ mol−1 for the composite membranes, indicating an improved proton mobility where the GO worked as a carrier-bridge for a smooth proton transfer into the polymer matrix. Furthermore, the H2 permeability reached 1.3 Barrer at 140 °C, indicating the fabrication of tightly-packed membranes. These results provide a very promising membrane for fuel cell applications.

(Energy Technology Division Research Award) The Emerging Research Needs of Polymer Electrolyte Membrane Electrolysis Cells

Proton conducting polymer electrolyte membrane (PEM) electrolysis has emerged as the currently favored research area to enable a global transformation of the energy system with hydrogen from renewable sources as a critical central feature. The hydrogen council has suggested that hydrogen impacts by 2050 could be $2.5T annually and 18% of total global energy demand.[1] While other electrolysis routes including traditional alkaline (based on aqueous KOH), alkaline membrane (emerging) and solid oxide electrolysis are all also being explored, and other possible hydrogen production pathways exist. The ability of PEM electrolysis to fit the needs of the emerging energy system as a dispatchable resource meeting cost, performance and durability requirements most effectively has led to a greater focus on PEM electrolysis than other electrolysis approaches within the global R&D community. The extent PEM electrolysis will establish itself commercially will depend largely on the advances made in the next several years.Much of the focus on PEM electrolysis has been centered around the advances made in PEM fuel cells, and the belief that these advances can be translated to PEM electrolysis systems. In particular, PEM fuel cells have largely been designed for transportation applications where they operate at low duty cycles (mostly off), and experience significant start-stop cycling (multiple times per day) while still achieving requisite performance and durability (several years).[2] Renewable energy sources are dramatically impacting the cost and availability of electricity and the ability to translate these resources into other energy sectors – most notably transportation and industry. While it is hoped that PEM electrolyzers can achieve cost, performance and durability targets, the research needs and challenges are not identical to PEM fuel cells.A new Department of Energy Consortium (H2NEW – Hydrogen from Next-generation Electrolyzers of Water) funded out of the Hydrogen and Fuel Cell Technologies Office is focused on enabling the cell-level fundamental understanding and advances required to address achieving $2/kg hydrogen through electrolysis. The primary focus of this effort is PEM electrolysis, the focus of the talk.A challenge in meeting the cost, performance and durability of PEM electrolysis systems is that current systems have had a strong emphasis on efficiency and durability. This means that cost has not been a primary concern such that systems could be “over-engineered” using extra or more expensive components and processing techniques. This approach has meant that little is understood about fundamental degradation rates relevant to systems that have not been over-engineered. Additionally, the markets that these devices have been sold into have typically operated under continuous conditions rather than the variable, intermittent load profiles that could couple to renewable or low-cost electricity inputs expected in the future. A clear understanding of the optimum system and operating conditions is not well understood at this time, nor is the impact of such operating conditions on performance and durability.Research needs place a high priority on durability under variable operating conditions. Specific components have susceptibility to different performance and durability impacts. In this talk, the impact of operating conditions and a discussion of projected operating conditions will be discussed. The concerns for both performance and durability will be discussed at the cell level with consideration of various cell components including catalyst, polymer, electrode, and porous transport layers. Accelerated stress tests for components in cells is a critical need and will also be presented. Finally, system and techno-economic considerations will also be included.References Hydrogen Council. “Hydrogen Scaling Up.” November 2017. http://hydrogencouncil.com/hydrogen-scaling-up/ B Pivovar, N Rustagi, S Satyapal, Electrochemical Society Interface 27 (1), 47.

Lithium propanesulfonyl(trifluoromethylsulfonyl)imide grafted polybenzimidazole as a self-supporting single ion conducting polymer electrolyte membrane for lithium metal secondary batteries

Dendrite growth and unstable solid electrolyte interphase are two challenges for lithium metal secondary batteries. Immobilization of anions to allow the transportation of cations only, namely single ion conductor, can prevent from concentration polarization and therefore is likely to suppress dendrite growth. In this article, poly(4,4′-(diphenyl ether)-5,5′-bibenzimidazole) (PBI) grafted with lithium propanesulfonyl(trifluoromethylsulfonyl)imide (LiPSTFSI) is found to form a uniform self-supporting single ion conducting polymer electrolyte membrane (PBI-g-LiPSTFSI). The ionic conductivity of the gel polymer electrolyte is 0.15 mS cm−1 at 25 °C. Coupled with a high lithium ion transference number of 0.91, the polymer electrolyte can withstand a 1000 h galvanostatic cycling at 0.5 mA cm−2 with a Li plating/stripping capacity of 2.5 mAh cm−2 without short circuit. Even increasing the mass loading of LiFePO4 up to 10.2 mg cm−2, the single ion conducting lithium metal secondary battery can deliver 166 mAh g−1 at 0.1 C, 160 mAh g−1 at 0.2 C and 152 mAh g−1 at 0.3 C. Because the rigid polymer chains and strong pi-pi stacking of PBI provide high mechanical strength and excellent thermal stability, PBI-g-LiPSTFSI is a promising single ion conducting polymer electrolyte for safe lithium metal secondary batteries.

Quasi-solid single ion conducting polymer electrolyte membrane containing novel fluorinated poly(arylene ether sulfonimide) for lithium metal batteries

A novel synthesis route for a fluorinated poly (arylene ether sulfonimide) (PAESI) homopolymer with high molecular weight and excellent dispersity was developed. The sulfonimide anion moiety and –C(CF3)2 functional group, located at the polymer backbone, provide for sufficient oxidative stability, single ion conducting (SIC) properties and increased mixability with PVdF-HFP to achieve a co-polymer, which facilitates formation of highly homogeneous and mechanically stable single ion conducting polymer electrolyte (SIPE) membranes in combination with ethylene carbonate (EC):propylene carbonate (PC) (1:1) and EC:dimethyl carbonate (DMC) (1:1) as solvents. Solvent uptake has a major impact on the ionic conductivity of these blend membranes, which was further elucidated by analysis of cation coordination and transport from atomistic molecular dynamic (MD) simulations to gain insight into lithium ion transport. Moreover, the thermal behavior of the novel single ion conducting polymer was investigated before and after lithiation, showing thermal stabilization of the sulfonimide group and the increase of the glass transition temperature (Tg). Dynamic mechanical analysis (DMA) revealed high mechanical strength of the blend membranes and the observations in lithium plating/stripping experiments in Li||Li- and Cu||Li cells implied excellent stability against lithium metal and the penetration by lithium deposits. In lithium iron phosphate (LFP)||Li cells, the SIPE membranes exhibited excellent cycling stability and rate performance.

Ionic Liquid-Incorporated Zn-Ion Conducting Polymer Electrolyte Membranes.

In this study, novel ionic liquid-incorporated Zn-ion conducting polymer electrolyte membranes containing polymer matrix poly (vinylidene fluoride-hexafluoropropylene) (PVdF-HFP) and 1-ethyl-3-methylimidazolium trifluoromethanesulfonate (EMITf), along with zinc trifluoromethanesulfonate Zn(Tf)2, are prepared and investigated. It is ascertained that the optimal membrane ILPE-Zn-4 (the mass ratio of EMITf:Zn(Tf)2:PVDF-HFP is 0.4:0.4:1), with abundant nanopores, exhibits a high amorphousness. At room temperature, the optimized electrolyte membrane offers a good value of ionic conductivity (~1.44 × 10−4 S cm−1), with a wide electrochemical stability window (~4.14 V). Moreover, the electrolyte membrane can sustain a high thermal decomposition temperature (~305 °C), and thus its mechanical performance is sufficient for practical applications. Accordingly, the ionic liquid-incorporated Zn-ion conducting polymer electrolyte could be a potential candidate for Zn-based energy storage applications.

Nanometer-Scale Water Dynamics in Nafion Polymer Electrolyte Membranes: Influence of Molecular Hydrophobicity and Water Content Revisited.

The ionic conductivity of polymer electrolyte membranes (PEMs) is an essential parameter for their device applications. In water-swollen PEMs, protons and other ions are transferred through hydrophilic channels of a few nanometers in diameter at most. Thus, optimizing the chemical and physical properties of the channels can enhance the conductivity of PEMs. However, the factors controlling the conductivity have not been completely clarified. Here, we report that measurements taken near the channel walls by a special nuclear magnetic resonance technique with ≤1 nm spatial resolution showed the largest water diffusivity when ∼80% of hydrophilic sulfonic acid groups were blocked, but the proton conductivity was low. The water diffusivity was much less affected by differences in water content. Our results provide a concept for changing the properties of PEMs and a challenge to implement the improved diffusivity in a way that enhances net ion conductivity.

Highly conductive and nonflammable composite polymer electrolytes for rechargeable quasi-solid-state Li-metal batteries

Solid-state Li-metal batteries are promising as next-generation energy storage devices. However, the main bottlenecks are the poor conductivity of the solid electrolyte and the high interfacial resistance. While polymers exhibit a lower interfacial resistance in comparison to ceramics, they often require the inclusion of flammable solvents. In this work, highly conductive composite polymer electrolyte (CPE) membranes are prepared by integrating a poly(vinylidene fluoride) matrix (PVDF) with a Li-conductive perovskite (i.e., Li0.38Sr0.44Ta0.70Hf0.30O2.95F0.05, LSTHF), a flame-retarding solvent (i.e., trimethyl phosphate (TMP)), and a Li salt (i.e., LiClO4). The CPE membrane with 10 wt% LSTHF (CPE-10) exhibits conductivities as high as 0.53 mS cm−1 at room temperature (RT) and 0.36 mS cm−1 at 0 °C. Furthermore, prototype batteries, including the CPE-10 electrolyte, show high initial discharge capacities, good rate capabilities, and stable cycling performance at either RT or 5 and 60 °C. This study illustrates that including a Li-conductive perovskite and TMP in a PVDF-based polymer material could yield safe, high-performance quasi-solid-state Li-metal batteries capable of operating over a relatively wide temperature range.

Effect of deep eutectic solvents hydrogen bond acceptor on the anhydrous proton conductivity of Nafion membrane for fuel cell applications

This study intended to assess the role of halogens on proton conductivity of polymer electrolyte membranes (PEMs) for fuel cell applications. For this purpose, the halogens were used as hydrogen bond acceptors (HBA) to form deep eutectic solvents (DES) which were later used as electrolyte in Nafion membrane. The prepared DESs were initially characterized in terms of rheology, thermal behavior, and ionic conductivity. Then, Nafion/DES composite membranes were prepared and their electrochemical reactions, thermal stabilities and proton conductivities were characterized. Interestingly, the bromide containing DESs provided super proton conductivity in Nafion/DES composites so that a proton conductivity of 337 mS/cm was achieved at 100 °Cat anhydrous condition which was about 120% higher than the iodide based Nafion/DES membranes and about 1200 % higher than other Nafion/ionic liquid PEMs at anhydrous condition. An upper bound concept was introduced for the Nafion/DES composite membranes which was compared with those obtained for conventional Nafion/ionic liquid composite membranes at anhydrous conditions. Furthermore, fuel cell performance of Nafion/DES composite membrane showed that DESs can be considered as proper electrolytes for anhydrous PEMs, and their properties can be justified by halogen type.

Effect of Mg(CF3SO3)2 concentration on structural and electrochemical properties of ionic liquid incorporated polymer electrolyte membranes

In the present study, a magnesium ion conducting polymer electrolyte membrane system based on polyethylene oxide (PEO) containing magnesium triflate Mg(CF3SO3)2 salt and 1-ethyl-3-methylimidazolium tetrafluoroborate (EMIM-BF4) ionic liquid is prepared using standard solution casting technique. X-ray diffraction and differential scanning calorimetry studies reveal change in crystalline character with variation in Mg(CF3SO3)2 concentration within PEMs. Fourier transform infrared spectroscopy technique reflects ion-polymer interactions within the prepared polymer electrolyte system. Dielectric and modulus properties of prepared electrolyte membranes show significant changes in dielectric constant and relaxation behavior respectively on varying Mg(CF3SO3)2 concentration. The optimized polymer electrolyte membrane with 6 wt% of magnesium triflate salt shows maximum ionic conductivity of ~ 9.4 × 10−5 S cm−1 at room temperature. The ionic conductivity variation with temperature shows Arrhenius behavior for PEMs. The Mg2+ conduction within the PEMs is established using CV study and electrochemical stability window of ~ 4.0 V is determined using linear sweep voltammetry. The PEMs are dominantly ionic conducting with Mg2+ transport number ~ 0.22 for the optimized PEM.

Ion conductive polymer electrolyte membranes based on star-branched poly(ethylene-glycol tri-acrylate) and polysulfide macromonomers

This article presents star-branched polymeric co-networks consisting of a three-arm poly(ethylene glycol) acrylate macromonomers (PEG3A) and a three-arm polysulfide (PS) via UV photopolymerization for the development of ion conductive polymer electrolyte membrane (PEM) containing succinonitrile (SCN) plasticizer and lithium bis(trifluoromethane sulfonyl)imide (LITFSI) salt. The hyperbranched co-network (PS-co-PEG3A) exhibits a lower glass transition temperature (Tg = −49 °C at 50:50) relative to that of 3-arm (PEG3A), i.e., Tg of −32 °C, showing systematic variation with polysulfide addition. In the tensile tests, elongation-at-break of PEM – PS-co-PEG3A is higher, but it occurs at the expense of lower tensile strength and modulus. Moreover, PEM – PEG3A exhibits higher strength and modulus relative to those of PEM – PS-co-PEG3A copolymer, but its ionic conductivity is lower (i.e., 3.41 × 10−4 S/cm for PEM – PEG3A versus 1.35 × 10−3 S/cm for PEM – PS-co-PEG3A at 21 °C). This improved ionic conductivity may be attributed to reduced crosslinking density associated with the formation of SC bonds upon addition of polysulfide. The PEM – PS-co-PEG3A co-network is thermally stable up to 130 °C tested and exhibited reasonably good anodic stabilities up to 4.5 V versus Li/Li+. In the CV tests in half-cells configuration with LiFePO4 cathode against Li/Li+, the specific discharge capacity was found to be 120 mAh/g with capacity retention of about 97% for 50 cycles tested.

Role of dinitrile plasticizer chain lengths in electrochemical performance of highly conductive polymer electrolyte membrane for lithium ion battery

The present article entails the effect of chain lengths or number of carbons (n) of dinitrile plasticizers (NC-(CH2)n-CN) in ionic conductivity and electrochemical stability of polymer electrolyte membranes (PEM) containing poly(ethylene glycol diacrylate) (PEGDA) precursor and lithium bis(trifluoromethane sulfonyl)imide (LiTFSI) salt. Ternary phase diagrams of PEGDA, dinitrile plasticizers/ionizers such as succinonitrile (SCN, n = 2), glutaronitrile (GLN, n = 3), and adiponitrile (ADN, n = 4) plasticizers, and LiTFSI salt blends were established to provide guidance for photo-curing the amorphous PEM mixtures. The resulting photo-cured PEM networks exhibited very high room-temperature ionic conductivity at the level of 10−3 S/cm. Among them, the GLN-plasticized PEM revealed the highest ionic conductivity (∼2.3 × 10−3 S/cm) with a very wide working temperature window from −80 °C to 60 °C. The electrochemical stability of these dinitrile-plasticized PEM networks was evaluated in half-cell configurations (viz., Li4Ti5O12/PEM/Li and LiFePO4/PEM/Li) using Li4Ti5O12 (LTO) and LiFePO4 (LFP) electrodes by means of potentiostat for cyclic voltammetry and galvanostatic charge-discharge cycling. The effect of chain lengths of the dinitrile plasticizers on the electrochemical performance of the PEM network is discussed.

Development of proton-exchange polymer nanocomposite membranes for fuel cell applications

The design and development of proton conducting polymer electrolyte membranes from a linear constituent, sulfonated poly (ether ether ketone) (SPEEK), and inorganic additive, niobium oxide (NBO), have been achieved. The degree of sulfonation of SPEEK was measured by back titration method and found to be 57%. The physicochemical properties such as water uptake ability, ion-exchange capacity, swelling ratio, proton conductivity, and thermal stability of the prepared polymer nanocomposite membranes were studied in detail. The distribution of NBO throughout the polymer matrix has been examined by scanning electron microscopic and X-ray diffraction analyses and found to be uniform. The SP-NBO-10 composite membrane shows 38.4% of water uptake, whereas the pristine membrane limits to 27.1%. The prepared electrolyte membranes exhibit good proton conductivity at temperature varying from 30°C to 90°C and possess less activation energy for the transportation of proton by the incorporation of NBO filler. The thermal studies demonstrated that the stability of the composite membranes was significantly enhanced by the impregnation of NBO. The filler NBO shows excellent improvements on the polymer nanocomposite, making it a very promising additive for other polymers and offers new roads for energy applications.

High-Performance Polymer Fiber Membrane Based Direct Methanol Fuel Cell System with Non-Platinum Catalysts

The broad application of direct methanol fuel cells (DMFCs) is impeded by the high cost of catalysts, the unsatisfied ionic conductivity of polymer electrolyte membrane (PEM), and the methanol cros...

Elastic Single-Ion Conducting Polymer Electrolyte

Single-ion conducting polymer electrolytes (SCPEs) are well recognized being the advanced electrolyte system with increased energy efficiency and prolonged cell lifetime due to their capability to mitigate electrode polarization and reduce electrolyte loss. Fabrication of stretchable SCPEs will definitely benefit the future stretchable batteries/electronics considering the advantageous electrolyte performance of the SCPE based systems, while no one report the SCPEs with specific mechanical performance. Herein, we will report the fabrication of a series of single-ion conducting polymer electrolyte membranes with high flexibility and stretchability. Polydimethylsiloxane (PDMS) network and polyethylene glycol (PEG) side chains are critical in retaining their satisfied mechanical and electrochemical performance. The investigation revealed that the incorporation of poly(ethylene glycol) methyl ether methacrylate (PEGMEMA) plays a significant role in forming the stretchable polymer membranes, which can not only lower the glass transition temperature but also provide additional reactivity. The obtained membranes exhibited 88%-252% elongation before breaks, and the mechanical properties, including Young’s modulus, toughness and tensile strength, are well adjustable by tuning the crosslinking density. Galvanostatic test of the assembled cells using the obtained SCPE member exhibited satisfied cycling performance with capacity retention up to 81.5% after 100 cycles. Figure 1

Synthesis of anion conducting polymer electrolyte membranes by Pd-Catalyzed Buchwald-Hartwig Amination coupling reaction

A novel aryl bromine bearing polymer was synthesized by Friedel-Crafts polycondensation. This precursor polymer substrate was used for C–N coupling via Buchwald-Hartwig amination to incorporate 9 examples of aryl amines into the polymer chains with high conversions (80–100%). Two aminated polymers were subsequently quaternized to give anion conducting polymers. These quaternary ammonium polymers show promising electrochemical membrane property because of their ability to transport mobile anions through the material while being electrically insulating. Membrane characteristics crucial to high electrochemical performance including ion exchange capacity, anion conductivity, water uptake, swelling ratio, and alkaline stability were evaluated.