High thermomechanical stability and ion-conductivity of anion exchange membranes based on quaternized modified poly(oxyndoleterphenylene)

To achieve good stability of anion‐exchange membranes. We report an organic–inorganic composite anion exchange membrane based on polyphenylene oxide (PPO) and 3‐[2‐(2‐aminoethylamino)ethylamino]propyl‐trimethoxysilane to improve dimensional stability and mechanical stability without affecting ionic conductivity. The successful synthesis of the membranes was confirmed by FT‐IR, 1H NMR, and EDX. The SiOSi three‐dimensional network cross‐linked structure was formed inside the anion‐exchange membranes by added inorganic fillers. It suppressed the swelling behavior of the membrane after water uptake, with water uptake rate of 48.2%–55.6% and swelling rate of 3.1%–14.2%. It improved the mechanical strength of the membranes with tensile strength of 33.5–37.8 MPa as the ratio of the membrane structure varied. Meanwhile, the flexible chain segments in the polymer structure contributed to the formation of microscopic phase separation structures, and the constructed ion‐conducting channels enabled QPPO‐Si‐5 to reach the highest hydroxide ion conductivity of 78.7 mS/cm at 80°C (ion exchange capacity [IEC] value of 1.2 mmol/g). QPPO‐Si‐1 exhibited better long‐term chemical stability, retaining 48.3% of the initial conductivity (30.8 mS/cm) after 600 h of alkali stability testing at 80°C in 1 M KOH solution. In conclusion, the results of this study provide a facile synthetic strategy with improved membrane's comprehensive performance.

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“…The SR of the membrane was calculated from the length of the membrane 22,23 . The formula for calculating the SR was as follows:

Swelling ratio (() %) goodbreak= \frac{L_{wet} - L_{dry}}{L_{dry}} goodbreak\times 100 %

where, L wet and L dry are the wet length and dry length of the membrane, respectively.…”

Section: Experimetalmentioning

confidence: 99%

“…The SR of the membrane was calculated from the length of the membrane. 22,23 The formula for calculating the SR was as follows:…”

Section: Ion Exchange Capacity Wu and Swelling Ratio (Sr)mentioning

confidence: 99%

A novel anion exchange membrane based on silicone/polyphenylene oxide with excellent ionic conductivity for AEMFC

Liu

Wang

Sui

et al. 2022

Polymers for Advanced Techs

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“…As a promising clean energy conversion technology, anion exchange membrane fuel cells (AEMFCs) have aroused widespread attention because of fast oxygen reduction reaction, which allows the use of non-noble metals as electrocatalysts. − As the core component of AEMFCs, the anion exchange membrane (AEM) transports hydroxide ions from cathode to anode, separates the two electrodes, and prevents crossover of fuel. − Developing highly conductive, alkali-stable AEM is in great need for fuel cell application. The past few decades have witnessed a great progress in AEM performance improvement, which is achieved via strategies such as hydrophilic/hydrophobic microphase separation, new backbone design and cation modification.…”

Section: Introductionmentioning

confidence: 99%

Hydrophilic–Hydrophobic Bulky Units Modified Anion Exchange Membranes for Fuel Cell Application

Yuan

et al. 2022

ACS Sustainable Chem. Eng.

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The hydroxide conductivity and alkaline stability play a significant role in the application of an anion exchange membranes (AEMs) fuel cell. These high performances are closely related to the structure of the polymer. Side-chain structure is commonly used to construct microphase separation. On this basis, a new strategy is to incorporate a rigid bulky structure into an AEM to break chain packing and reduce resistance against hydroxide ion transport. In this work, rigid bulky hydrophilic–hydrophobic side-chain grafted, ether-free poly(biphenyl indole) (PBN) AEMs are designed and prepared by chemical incorporation of hydrophilic bulky cyclodextrin and hydrophobic bulky adamantane onto the PBN backbone. The enhanced driving force of microphase separation and the enlarged free volume can make for high hydroxide conductivity. The fabricated AEM with an ion exchange capacity (IEC) of 1.81 mmol g–1 shows a conductivity of 122.0 mS cm–1 at 80 °C, which can be retained by 90% after treatment of the AEM in a 1 M NaOH solution at 80 °C for 1008 h. Its single H2/O2 fuel cell yields a peak power density of 603 mW cm–2 at 60 °C; the fuel cell can maintain 70.2% of its initial voltage after operating for 30 h. This strategy provides a new and effective route for the preparation of AEMs with superior performance.

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“…To overcome this issue, ether-free polyaromatic backbones have been synthesized via various methods, including acid-catalyzed Friedel–Craft polycondensation, , Diels–Alder reaction, and metal-catalyzed coupling reactions . Among these methods, acid-catalyzed Friedel–Craft polycondensation is a promising strategy to fabricate AEM materials owing to its simple preparation, mild reaction conditions, and low cost (without expensive palladium catalysts). ,, Poly(arylene isatin) ,− is an ether-free polymer backbone with the advantages of facile preparation and functionalization. Ren et al prepared several poly(oxindole biphenylene) (POXI)-based AEMs with different spacer lengths.…”

Section: Introductionmentioning

confidence: 99%

Cross-Linked Anion-Exchange Membranes with Dipole-Containing Cross-Linkers Based on Poly(terphenyl isatin piperidinium) Copolymers

Tian

et al. 2022

ACS Appl. Mater. Interfaces

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To balance the ionic conductivity and dimensional stability of anion-exchange membranes (AEMs), several cross-linked ether-free poly(terphenyl isatin piperidinium) copolymers were synthesized using 1,2-bis(2-aminoethoxy)ethane as a cross-linker. By introducing an alkyl diamine-based hydrophobic cross-linker as a control, the effects of the dipolar-molecule-containing cross-linker on the comprehensive performance of the membranes were investigated. Cation–dipole interactions between the cations and the hydrophilic ethylene oxide cross-linker enhance the self-assembly capability of the cationic groups. The introduction of the rotatable ethylene oxide cross-linker facilitates the flexibility of the cross-linked networks, thereby promoting hydrophilic/hydrophobic phase separation and inhibiting excessive swelling of the corresponding AEMs simultaneously. The resulting PTPBHIN-O19 membrane showed a high hydroxide conductivity (151.69 mS cm–1) and low swelling ratio (10.53%) at 80 °C. Furthermore, owing to the cross-linked structure and ether-free polymer backbone with high alkali resistance, the membranes treated in 3 M NaOH at 80 °C for 1600 h maintained ≥85% of their hydroxide conductivity, indicating excellent alkaline stability. A H2/O2 fuel cell based on the PTPBHIN-O19 AEM exhibited a maximum power density of 398 mW cm–2 at 515 mA cm–2.

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High thermomechanical stability and ion-conductivity of anion exchange membranes based on quaternized modified poly(oxyndoleterphenylene)

Cited by 16 publications

References 34 publications

A novel anion exchange membrane based on silicone/polyphenylene oxide with excellent ionic conductivity for AEMFC

A novel anion exchange membrane based on silicone/polyphenylene oxide with excellent ionic conductivity for AEMFC

Hydrophilic–Hydrophobic Bulky Units Modified Anion Exchange Membranes for Fuel Cell Application

Cross-Linked Anion-Exchange Membranes with Dipole-Containing Cross-Linkers Based on Poly(terphenyl isatin piperidinium) Copolymers

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