Cross-linked anion exchange membranes with flexible,long-chain,bis-imidazolium cation cross-linker

Herein, poly (phenylene) oxide (PPO)-based cross-linked anion exchange membranes (AEMs) with flexible, long-chain, bis-imidazolium cation cross-linkers are designed and synthesized. Although the cross-linked membranes possess high ion exchange capacity (IEC) values of up to 3.51–3.94 meq g⁻¹, they have a low swelling degree and good mechanical strength because of their cross-linked structure. Though the membranes with the longest flexible bis-imidazolium cation cross-linker (BMImH-PPO) possess the lowest IEC among these PPO-based AEMs, they show the highest conductivity (24.10 mS cm⁻¹ at 20 °C) and highest power density (325.7 mW cm⁻² at 60 °C) because of the wide hydrophilic/hydrophobic microphase separation in the membranes that promote the construction of ion transport channels, as confirmed by atom force microscope (AFM) images and the small angle X-ray scattering (SAXS) analyses. Furthermore, the BMImH-PPO samples exhibit good chemical stability (10% and 6% decrease in IEC and conductivity, respectively, in 2 M KOH at 80 °C for 480 h, and a 22% decrease in weight in Fenton's reagent at 60 °C for 120 h), making such cross-linked AEMs potentially applicable in alkaline anion exchange membrane fuel cells.     

Anion exchange membranes of bis-imidazolium cation crosslinked poly(2,6-dimethyl-1,4- phenylene oxide) with enhanced alkaline stability

Partially crosslinked anion exchange membranes (AEMs) with imidazolium-based cationic functionalities were fabricated based on a poly(2,6-dimethyl-1,4-phenylene oxide) (PPO) matrix. The PPO was activated by bromomethylation and functionalized with methylimidazole and 1,4-bis(imidazolyl)butane at different ratios through a gentle and facile heat curing method. The use of 1,4-bis(imidazolyl)butane resulted in a membrane with cationic functionalities incorporated in covalent crosslinks, which allowed for high ion exchange capacities (IECs) without compromising on mechanical robustness. Comprehensive characterizations were performed in terms of thermal stability, water uptake, IEC, swelling, conductivity, mechanical properties and alkaline stability to investigate the correlation of the structure and physicochemical properties. Comparing with the un-crosslinked imidazolium PPO membrane, crosslinked membranes exhibited improved mechanical robustness and alkaline stabilities. The membrane with a crosslinking degree of 10% displayed an IEC of around 1.5 mmol g⁻¹, tensile strength of 4.1 MPa, hydroxide ion conductivity of 40.5 mS cm⁻¹, and a retained ratio in conductivity of 40% after tolerance test of nearly 150 h in 1 mol L⁻¹ KOH (aq.) at 60 °C.     

A facile fabrication of functionalized rGO crosslinked chemically stable polysulfone-based anion exchange membranes with enhanced performance

Introducing more ionic conductive groups in polymer-based anion exchange membranes (AEMs) can improve the ion exchange capacity and further overcome the disadvantage of low ion conductivity for AEMs. However, the excessive swelling of AEMs caused by exorbitant IEC value may reduce the dimensional stability of membranes. So it is extremely important to modify the structures of AEMs. Herein, we proposed a facile strategy to construct reduced graphene oxide (rGO) stable crosslinked polysulfone-based AEMs with improved properties. rGO was non-covalently modified with pyrene-containing tertiary amine small molecule and polymer via π-π interactions. The as-prepared functionalized rGO (TrGO and PrGO) as both cross-linkers and fillers to fabricate quaternized polysulfone (QPSU)-based AEMs (CQPSU-X-TrGO and CQPSU-X-PrGO) for the first time. The cross-linked membranes can tighten the internal packing structure, and enhance the alkaline resistance, ion conductivity and oxidative stability of AEMs. Furthermore, the hydrophilicity and flexibility of the CQPSU-X-PrGO membranes were significantly improved as compared with that of CQPSU-X-TrGO membranes. PrGO-crosslinked membranes (CQPSU-2%-PrGO, σ_OH⁻ = 117.7 mS/cm) displayed higher ionic conductivities at 80 °C than TrGO-crosslinked membranes (CQPSU-1%-TrGO, σ_OH⁻ = 87.2 mS/cm). The remarkable nanophase separation can be observed in the CQPSU-X-PrGO membranes by TEM. This feasible strategy can be efficiently used to prepare new type of crosslinked organic-inorganic nanohybrid AEMs with excellent chemical stability and high ionic conductivity.     

Dense 1,2,4,5-tetramethylimidazolium-functionlized anion exchange membranes based on poly(aryl ether sulfone)s with high alkaline stability for water electrolysis

Anion exchange membranes with enough alkaline stability and ionic conductivity are essential for water electrolysis. In this work, a class of anion exchange membranes (PAES-TMI-x) with dense 1,2,4,5-tetramethylimidazolium side chains based on poly(aryl ether sulfone)s are prepared by aromatic nucleophilic polycondensation, radical substitution and Menshutkin reaction. Their chemical structure and hydrophilic/hydrophobic phase morphology are characterized by hydrogen nuclear magnetic resonance (¹H NMR) and atomic force microscope (AFM), respectively. The water uptake, swelling ratio and ionic conductivity for PAES-TMI-x are in the range of 23.8%–48.3%, 8.3%–14.3% and 18.22–96.31 mS/cm, respectively. These AEMs exhibit high alkaline stability, and the ionic conductivity for PAES-TMI-0.25 remains 86.8% after soaking in 2 M NaOH solution at 80 °C for 480 h. The current density of 1205 mA/cm² is obtained for the water electrolyzer equipped with PAES-TMI-0.25 in 2 M NaOH solution at 2.0 V and 80 °C, and the electrolyzer also has good operation stability at current density of 500 mA/cm². This work is expected to provide a valuable reference for the selection and design of cations in high-performance AEMs for water electrolysis.     

Block poly(arylene ether nitrile ketone)s with comb-shaped alkyl chains as anion exchange membranes

A new approach is presented here for constructing higher-performance anion exchange membranes (AEMs) by combining block-type and comb-shaped architectures. A series of quaternization fluorene-containing block poly (arylene ether nitrile ketone)s (QFPENK-m-n) were synthesized by varying the length of hydrophobic segment as AEMs. The well-designed architecture, which involved grafting comb-shaped C10 long alkyl side chains onto the block-type main chains, formed efficient ion-transport channels, as confirmed by atomic force microscopy. As a result, the AEMs showed high hydroxide conductivities in the range of 34.3–102.1 mS⋅cm⁻¹ from 30 to 80 °C at moderate ion exchange capacities (IECs). Moreover, the hydrophobic segment with nitrile groups also exhibited a profound anti-swelling property for the AEMs, resulting in ultralow swelling ratios ranging from 4.7% to 7.1% at 30 °C and 7.5%–9.8% at 80 °C, as well as superb conductivity-to-swelling ratios at 80 °C. In addition, the AEMs displayed good mechanical properties, thermal and oxidative stability, and optimizable alkaline stability.     

Mechanically robust semi-interpenetrating polymer network via thiol-ene chemistry with enhanced conductivity for anion exchange membranes

Anion exchange membranes (AEMs) have emerged as crucial functional materials in various electrochemical device, such as fuel cell. Both the mechanical property and ionic conductivity play important roles in AEMs. Herein, a series of semi-interpenetrating polymer network AEMs are prepared by introducing flexible polyvinyl alcohol to the rigid photo-crosslinked poly (2,6-dimethyl-1,4-phenylene oxide) network. Such strategy endows AEM with tunable composition and mechanical property. Among these AEMs, membrane with an IEC of 1.46 mmol/g shows the highest mechanical strength of 30.8 MPa and a relatively lower swelling ratio, as well as the highest hydroxide conductivity. Importantly, the alkaline stability of these AEMs has been improved, 66.5% of the hydroxide conductivity is maintained after treatment in 1 M NaOH at 80 °C for 1000 h. Tentative assembly of H₂/O₂ fuel cell at 60 °C with this AEM displays a peak power density of 78 mW/cm². All the results demonstrate that sIPN structure is a promising way to enhance the mechanical property, ionic conductivity, and the alkaline stability of AEMs for the future application in AEMFCs.     

Macromolecular crosslink of imidazole functionalized poly(vinyl alcohol) and brominated poly(phenylene oxide) for anion exchange membrane with enhanced alkaline stability and ionic conductivity

Anion exchange membranes (AEMs) are important energy conversion device for fuel cell applications, where the overall redox reaction happened. Both alkaline stability and ionic conductivity should be considered in the long-term use of fuel cells. In this work, imidazole functionalized polyvinyl alcohol was designed as the functional macromolecular crosslinking agent to fabricate crosslinked AEMs with brominated poly(phenylene oxide) matrix. Benefitting from the macromolecular crosslinked structure, the membranes displayed enhanced ionic conductivity and alkaline stability at elevated temperature. Moreover, membrane with ion exchange capacity of 1.54 mmol/g displayed ionic conductivity of 78.8 mS/cm at 80 °C, and the conductivity could maintain 75% of the initial value after immersion in 1 M NaOH solution at 80 °C for 1000 h. Moreover, a peak power density of 105 mW/cm² was achieved when the assembled single cell with c-91 was operated at 60 °C. These results indicated that the construction of macromolecular crosslinked AEMs have great potential in the practical application of anion exchange membranes fuel cells.     

High chemical stability anion exchange membrane based on poly(aryl piperidinium): Effect of monomer configuration on membrane properties

In recent years, ether-free polyaryl polymers prepared by superacid-catalyzed Friedel-Crafts polymerization have attracted great research interest in the development of anion exchange membranes(AEMs) due to their high alkali resistance and simple synthesis methods. However, the selection of monomers for high-performance polymer backbone and the relationship between polymer structure construction and properties need further investigated. Herein, a series of free-ether poly(aryl piperidinium) (PAP) with different polymer backbone steric construction were synthesized as stable anion exchange membranes. Meta-terphenyl, p-terphenyl and diphenyl-terphenyl copolymer were chosen as monomers to regulate the spatial arrangement of the polymer backbone, which tethered with stable piperidinium cation to improve the chemical stability. In addition, a multi-cation crosslinking strategy has been applied to improve ion conductivity and mechanical stability of AEMs, and further compared with the performance of uncrosslinked AEMs. The properties of the resulting AEMs were investigated and correlated with their polymer structure. In particular, m-terphenyl based AEMs exhibited better dimensional stability and the highest hydroxide conductivity of 144.2 mS/cm at 80 °C than other membranes, which can be attributed to their advantages of polymer backbone arrangement. Furthermore, the hydroxide conductivity of the prepared AEMs remains 80%–90% after treated by 2 M NaOH for 1600 h, exhibiting excellent alkaline stability. The single cell test of m-PTP-20Q4 exhibits a maximum power density of 239 mW/cm² at 80 °C. Hence, the results may guide the selection of polymer monomers to improve performance and alkaline durability for anion exchange membranes.     

Enhanced ionic conductivity of anion exchange membranes by grafting flexible ionic strings on multiblock copolymers

A new strategy to prepare high-conductivity anion exchange membranes (AEMs) is presented here. A series of phenolphthalein-based poly(arylene ether sulfone nitrile) multiblock AEMs has been synthesized by selectively grafting flexible ionic strings on hydrophilic segments to form ionic regions. Moreover, the phenolphthalein groups are introduced to force chains apart and create additional interchain spacing. In addition, the nitrile groups suspended on main chains are aimed at enhancing the anti-swelling behavior of as-prepared AEMs. Along these processes, well-defined phase separation has been attained, forming excellent ion-transport channels. The effective phase separation has been confirmed by atomic force microscopy. Finally, as-prepared AEMs exhibit a high hydroxide conductivity, ranging from 40.1 to 121.6 mS cm⁻¹ in the temperature range of 30–80 °C, and superior ionic conductivity to IEC ratio at 80 °C. Furthermore, excellent thermal stability and desirable mechanical strength have been rendered by as-prepared AEMs. However, the alkaline stability of as-prepared AEMs requires further optimization.     

Preparation and characterization of imidazolium-based membranes for anion exchange membrane fuel cell applications

New anion exchange membranes (AEMs) with high conductivity, good dimensional and alkaline stability are currently required in order to develop alkaline fuel cells into efficient and clean energy conversion devices. In this study, a series of AEMs based on 1, 2-dimethyl-3-(4-vinylbenzyl) imidazolium chloride ([DMVIm][Cl]) are prepared and investigated. [DMVIm][Cl] is synthesized and used as ion carriers and hydrophilic phase in the membranes. The water uptake, swelling ratio, IEC and conductivity of the AEMs increase with increasing the [DMVIm][Cl]. The imidazolium-based AEMs show excellent thermal stability, sufficient mechanical strength, the membrane which containing 30% mass fraction of [DMVIm][Cl] shows conductivity up to 1.0 × 10^?2 S cm^?1 at room temperature and good long-term alkaline stability in 1 M KOH solution at 80 °C. The results of this study suggest that this type of AEMs have good perspectives for alkaline anion exchange membrane fuel cell applications.     

Bis-pyridinium crosslinked poly(ether ether ketone) anion exchange membranes with enhancement of hydroxide conductivity and alkaline stability

A series of tunable bis-pyridinium crosslinked PEEK-BiPy-x anion exchange membranes (AEMs) are prepared successfully to improve the “trade-off” between ionic conductivity and alkaline stability. The crosslinking density of bis-pyridinium is optimized to promote microphase separation and guarantee the free volume. All the PEEK-BiPy-x membranes have a distinct microphase separation pattern observed by atomic force microscopy (AFM) and the PEEK-BiPy-x membranes also display adequate thermal, mechanical and dimensional stability. Impressively, the PEEK-BiPy-0.5 membrane exhibits maximum tensile strength (58.53 MPa) and highest IEC of 1.316 mmol·g^?1. Meanwhile, its hydroxide conductivity reaches up to 70.86 mS·cm^?1 at 80 °C. Besides, great alkaline stability of PEEK-BiPy-0.5 membrane is obtained with conductivity retention of 91.74% after 1440 h in 1 M NaOH solution, owing to the crosslinked structure of the AEMs and steric effect of bis-pyridinium cations. Overall, the PEEK-BiPy-x membranes possess potential applications in AEMs.     

Polyaryl piperidine anion exchange membranes with hydrophilic side chain

Recently, the development of high-performance and durable anion exchange membranes has been a top priority for anion exchange membrane fuel cells. Here, a series of polyaryl piperidine anion exchange membranes with hydrophilic side chain (qBPBA-80-OQ-x) are prepared by the superacid-catalyzed Friedel-Crafts reaction. AFM images show that the hydrophilic side chain and hydrophobic main chain form a distinct microphase separation structure. The AEMs of qBPBA-80-OQ-100 and qBPBA-80 have close mechanical strength, but the ionic conductivity of the former (81 mS/cm, 80 °C) is higher than the latter (73 mS/cm, 80 °C). In addition, qBPBA-80-OQ-100 AEM loses by 15.0% after an alkaline treatment of 720 h, while qBPBA-80 AEM loses by 17.8%. The results indicate that the introduction of hydrophilic side chain not only promotes the formation of microphase separation structure, but also improves the ionic conductivity and alkaline resistance of polyaryl piperidine AEMs.     

Partially crosslinked comb-shaped PPO-based anion exchange membrane grafted with long alkyl chains: Synthesis,characterization and microbial fuel cell performance

Anion exchange membranes (AEMs) with higher ion exchange capacities (IECw) are limited to applications due to excessive swelling and higher water uptake. Crosslinked macromolecular structures have been a strategy to balance between ionic conductivity and swelling in membranes. However, highly crosslinked AEMs are usually mechanically brittle and poorer in ion transport. Thus we report a series of partially diamine crosslinked (X = 10%, 15%, 20%) comb-shaped AEMs functionalized with dimethylhexadecylammonium groups exhibiting improved flexibility, water uptake and swelling properties over conventional un-crosslinked or fully crosslinked materials. The higher conductivities in these PPO AEM(X) (for example, X = 20%, IECw = 1.96 mmol/g, σ(OH⁻) ~ 67 mS/cm at 80 °C) are attributed to the distinct nanophase separation as observed in SAXS and AFM analyses. Finally, the microbial fuel cell performances of the membranes were compared with commercially available cation and anion exchange membranes.     

Guanidinium cationic covalent organic nanosheets-based anion exchange composite membrane for fuel cells

Covalent organic frameworks (COFs) used for anion exchange membrane fuel cells (AEMFCs) are commonly endowed with ion conductivity by post-synthesis modification. However, this method usually results in uneven distribution of functional groups, low functionalization and severe ion capacity fade. Limited by hydrophobic skeleton and relatively large particle size of COFs, the COFs doping amount of the composite membrane is not high. Here we design and synthesize a series of guanidinium cationic covalent organic nanosheets-based anion exchange composite membranes. The positively charged guanidinium group as a building block can induce COF-DhaTG_Cl self-exfoliation into a few layered nanosheets through strong interlayer repulsion. Then, the nanosheets were introduced into quaternary ammonium-functionalized poly(2,6-dimethyl-1,4-phenyl ether) (QPPO). A series of COF-DhaTG_Cl/PPO composite AEMs was prepared with the highest doping amount of 30 wt% by casting method. The porous structure and repeat cationic guanidinium units on the skeleton will expose ion sites to the target ones, providing faster OH⁻ diffusion kinetics in one-dimensional channels. The OH⁻ conductivity of COF-DhaTG_Cl/PPO-20 composite membrane can reach 148.65 mS/cm at 80 °C. Meanwhile, the composite membrane also exhibits enhanced mechanical strength and alkaline stability with the maximum stress strength of 37.3 MPa and the residual conductivity of 96.29% after immersion in 2 M NaOH solution at 60 °C for two weeks.     

Preparation and characterization of a polyvinyl alcohol grafted bis-crown ether anion exchange membrane with high conductivity and strong alkali stability

A new type of symmetrical bis-crown ether is prepared by connecting dibenzo-18-crown-6 ether on both sides of the chromotropic acid, and then grafting the aforementioned bis-crown ether onto polyvinyl alcohol matrix to prepare a series of anion exchange membranes (AEMs), which their have high conductivity and strong alkali stability. These synthesized membranes were named B-C_X%-P AEMs (x is the mass percentage of the symmetrical bis-crown ether (B–C)). Then, the chemical structure of aforementioned AEMs were verified by means of ¹H NMR, FT-IR and UV. Meanwhile, the OH⁻ conductivity, alkaline stability and single cell performance of the synthesized membrane were also investigated. The results revealed that the conductivity of B–C_30%-P membrane is the highest at 80 °C (235 mS cm⁻¹), and the power density is also the highest (197 mW cm⁻²), and the alkali stability of the membrane synthesized in this paper was also improved. The conductivity at 80 °C was only reduced by 4%, which was obtained by immersing the B–C_30%-P membrane immersed in 6 mol L⁻¹ KOH solution for 168 h, which the aforementioned results proved that the synthesized membrane in this research had excellent OH⁻ conductivity and alkaline stability.     

High alkaline stability and long-term durability of imidazole functionalized poly(ether ether ketone) by incorporating graphene oxide/metal-organic framework complex

The poly(ether ether ketone) (PEEK) was prepared as organic matrix. ZIF-8 and GO/ZIF-8 were used as fillers. A series of novel new anion exchange membranes (AEMs) were fabricated with imidazole functionalized PEEK and GO/ZIF-8. The structure of ZIF-8, GO/ZIF-8 and polymers are verified by ¹H NMR, FT-IR and SEM. This series of hybrid membranes showed good thermal stability, mechanical properties and alkaline stability. The ionic conductivities of hybrid membranes are in the range of 39.38 mS cm^?1–43.64 mS cm^?1 at 30 °C, 100% RH and 59.21 mS cm^?1–86.87 mS cm^?1 at 80 °C, 100% RH, respectively. Im-PEEK/GO/ZIF-8-1% which means the mass percent of GO/ZIF-8 compound in Im-PEEK polymers is 1%, showed the higher ionic conductivity of 86.87 mS cm^?1 at 80 °C and tensile strength (38.21 MPa) than that of pure membrane (59.21 mS cm^?1 at 80 °C and 19.47 MPa). After alkaline treatment (in 2 M NaOH solution at 60 °C for 400 h), the ionic conductivity of Im-PEEK/GO/ZIF-8-1% could also maintain 92.01% of the original ionic conductivity. The results show that hybrid membranes possess the ability to coordinate trade-off effect between ionic conductivity and alkaline stability of anion exchange membranes. The excellent performances make this series of hybrid membranes become good candidate for application as AEMs in fuel cells.     

Facile self-crosslinking to improve mechanical and durability of polynorbornene for alkaline anion exchange membranes

Crosslinking is a valid approach to enhance the mechanical and durability performance of anion exchange membranes (AEMs). Herein, a facile and effective self-crosslinking strategy, with no need for an additional crosslinker or a catalyzer, is proposed. A series of tunable self-crosslinking and ion conduction polynorbornene membranes are designed. The 5-norbornene-2-methylene glycidyl ether (NB-MGE) component which affords self-crosslinking enhances dimensional stability, while the flexible 5-norbornene-2-alkoxy-1-hexyl-3-methyl imidazolium chloride (NB-O-Im⁺Cl⁻) hydrophilic unit contributes high conductivity. The crosslinking significantly decreases the water uptake, and water swelling ratio provides excellent solvent-resistance and enhances the thermal and mechanical properties. Additionally, crosslinked rPNB-O-Im-x AEMs exhibit desirable alkaline stability. Impressively, the rPNB-O-Im-30 (IEC = 1.377) shows a moderate ion conductivity (61.8 m S cm⁻¹, 80 °C), with a suppressed water absorption and 88.17% initial OH⁻ conductivity is maintained after treated for 240 h with a 1.0 M NaOH solution at 60 °C. Suitably assessed of rPNB-O-Im-30 AEM reveals a 98.4 mW cm⁻² peak power density reached at a current density of about 208 mA cm⁻². The report offers a facile and effectual preparative technique for preparing dimensional and alkaline stable AEMs for fuel cells applications.     

Constructing an internally cross-linked structure for polysulfone to improve dimensional stability and alkaline stability of high performance anion exchange membranes

The preparation of quaternary ammonium polysulfone anion exchange membranes (AEMs) with good dimensional stability and alkaline stability is an urgent problem to solve. In response, a series of cross-linked based on polysulfone and 4, 4′-trimethylenedipiperidine (TMDP) as crosslinkers with different degrees AEMs were developed in this work through a simple process. Among the fabricated AEMs, CAPSF-5 exhibits superb alkaline stability in a 1 M KOH aqueous solution at 60 °C for 15 days, whereas the non-crosslinked APSF membrane became tremendously brittle within 24 h and could not be further studied under the same conditions. In addition, even at 60 °C, CAPSF-5 demonstrates a superior dimensional stability compared to the non-crosslinked APSF membrane due to the formation of a dense internal network structure. These observations demonstrate that crosslinked CAPSF membranes can be a viable strategy to improve the deficiency of the polysulfone backbone, especially in terms of alkaline stability.     

Constructing micro-phase separation structure by multi-arm side chains to improve the property of anion exchange membrane

In order to improve the performance of anion exchange membrane (AEMs) as the core component of alkaline fuel cell, a novel pentamethyl-contained phenolphthalein multi-arm monomer is synthesized. The highly imidazolium-functionalized poly (arylene ether ketone) membrane (Im-PEK-x) are prepared by introducing 1,2-dimethylimidazole as hydrophilic segments. The monomer, polymer and anion exchange membranes are confirmed by ¹H NMR spectra. The well-defined micro-phase separated structure of membranes is conducive to ion transport and the structure is investigated by TEM and SAXS. The imidazolium-functionalized membranes (Im-PEK-0.8) exhibits high ionic conductivity (0.148 S/cm at 80 °C). The tensile strength of Im-PEK-0.8 membrane is 30.06 MPa. Furthermore, after immersing in 60 °C, 2 M NaOH solution for 240 h, the ionic conductivity remains 0.092 S/cm for Im-PEK-0.8. The 1,2-dimethylimidazole enhance alkaline stability by steric effect of the substituent group at the C2 position. All these results indicate that this is a new method to enhance conductivity and stability performance of AEMs.     

Novel poly(carbazole-butanedione) anion exchange membranes constructed by obvious microphase separation for fuel cells

To develop anion exchange membranes with excellent chemical stability and high performance. A series of quaternary ammonium functionalized (hydrophilic) hydrophobic rigid poly (carbazole-butanedione) (HOCB-TMA-x) anion exchange membranes were prepared, where x represents the percentage content of hydrophobic unit octylcarbazole (OCB). Due to the introduction of hydrophobic rigid unit octylcarbazole and hexyl flexible side chain, the hydrophilic-hydrophobic microstructure of AEMs was developed. The AEMs exhibit excellent overall performance, specifically the low swelling ratio HOCB-TMA-30 membrane exhibits the highest OH^? conductivity of 152.9 mS/cm at 80 °C. Furthermore, the ionic conductivity of AEM decreased by only 9.5% after 2250 h of immersion in 1 M NaOH. The maximum peak power density of a single cell with a current density of 4.38 A/cm² at 80 °C was 1.85 W/cm².