Tetra-alkylsulfonate functionalized poly(aryl ether) membranes with nanosized hydrophilic channels for efficient proton conduction

Zhou, Lingjiu; Zhu, Junyang; Lin, Mei‐Jin; Xu, Jiaqi; Xie, Zailai; Chen, Dongyang

doi:10.1016/j.jechem.2019.02.013

Cited by 22 publications

(8 citation statements)

References 57 publications

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“…It can be seen that the tensile strength of the DQA-TAPFEs decreases with increasing IEC. This can be attributed to the increasing amount of water absorbed in the membrane, which acts as the plasticizer to reduce the strength . Nevertheless, the DQA-TAPFEs with moderate IECs exhibit good mechanical properties with tensile strengths over 30 MPa.…”

Section: Resultsmentioning

confidence: 99%

Densely Quaternized Fluorinated Poly(fluorenyl ether)s with Excellent Conductivity and Stability for Vanadium Redox Flow Batteries

et al. 2021

ACS Appl. Mater. Interfaces

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Cationic group distribution and elemental composition are two key factors determining the conductivity and stability of anion exchange membranes (AEMs) for vanadium redox flow batteries (VRFBs). Herein, fluorinated tetra-dimethylaminomethyl-poly(fluorenyl ether)s (TAPFE)s were designed as the polymer precursors, which were reacted with 6-bromo-N,N,N-trimethylhexan-1-aminium bromide to introduce di-quaternary ammonium (DQA) containing side chains. The resultant DQA-TAPFEs with a rigid fluorinated backbone and flexible multi-cationic side chains exhibited distinct micro-phase separation as probed by small-angle X-ray scattering (SAXS) and atomic force microscopy (AFM). DQA-TAPFE-20 with an ion exchange capacity (IEC) of 1.55 mmol g–1 exhibited a SO4 2– conductivity of 10.1 mS cm–1 at room temperature, much higher than that of a control AEM with an identical backbone but spaced out cationic groups, which had a similar IEC of 1.60 mmol g–1 but a SO4 2– conductivity of only 3.2 mS cm–1. Due to the Donnan repulsion effect, the DQA-TAPFEs exhibited significantly lower VO2+ permeability than Nafion 212. The VRFB assembled with DQA-TAPFE-20 achieved an energy efficiency of 80.4% at 80 mA cm–1 and a capacity retention rate of 82.9% after the 50th cycling test, both higher than those of the VRFB assembled with Nafion 212 and other AEMs in the literature. Therefore, the rationally designed DQA-TAPFEs are promising candidates for VRFB applications.

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Section: Resultsmentioning

confidence: 99%

Densely Quaternized Fluorinated Poly(fluorenyl ether)s with Excellent Conductivity and Stability for Vanadium Redox Flow Batteries

et al. 2021

ACS Appl. Mater. Interfaces

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“…During the last few decades, PEMs (such as perfluorosulfonic acid proton membranes) have been extensively studied for potential VRFB applications because of their high proton conductivity and chemical stability. − However, the large vanadium-ion permeability and manufacturing costs of these membranes significantly limited their commercialization . Therefore, various nonfluorinated aromatic polymer-based PEMs with sulfonic acid groups, such as sulfonated polyether ether ketone (PEEK), sulfonated polysulfone, and sulfonated poly(aryl ether ketone), have been prepared and used in VRFBs because of their good film-forming properties, excellent mechanical characteristics, low costs, and high long-term thermal stability. Although the conductivity of aromatic polymer-based PEMs can be increased to levels comparable to those of Nafion membranes by increasing their ion exchange capacity, the dimensional stability of these membranes may be significantly reduced in this process, which would increase their vanadium-ion permeability and deteriorate their mechanical properties, , Recently, Ding et.…”

Section: Introductionmentioning

confidence: 99%

Polyether Ether Ketone-Based Anion Exchange Membranes with Bis-imidazolium Cations for All-Vanadium Redox Flow Batteries

Yang

Chu

Xue

et al. 2021

ACS Appl. Energy Mater.

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In this study, a series of polyether ether ketone (PEEK)-based un-cross-linked and cross-linked anion exchange membranes (AEMs) with bisimidazolium cations are prepared to fabricate all-vanadium redox flow batteries (VRFBs). Compared with a Nafion 212 membrane, these AEMs exhibit significantly lower vanadium-ion permeabilities because of the Donnan exclusion effect of bis-imidazolium cations. Moreover, owing to their denser structure, the vanadium permeability of the cross-linked PEEK-based AEMs (CImPEEK) is less than that of the un-cross-linked PEEK-based AEMs (ImPEEK) with similar ion exchange capacity (IEC) values. The ImPEEK and CImPEEK membranes exhibited the vanadium-ion permeabilities of 4.7 × 10 −10 and 5.5 × 10 −11 cm 2 s −1 at room temperature, respectively, which are considerably lower than the permeability of the Nafion 212 membrane (8.9 × 10 −9 cm 2 s −1 ) under the same conditions. Furthermore, the PEEK-based AEMs are more chemically stable in an electrolyte solution than the Nafion 212 membrane. The VRFB containing a CImPEEK membrane demonstrate a Coulombic efficiency of 99.5% at a current density of 120 mA cm −2 , whereas the corresponding value obtained for the VRFB with a Nafion 212 membrane under the same conditions was 95.8%. Finally, the capacity retention of the former battery is superior to those of the VRFBs containing Nafion 212 and ImPEEK membranes. The results of this work indicate that CImPEEK is a promising membrane material for VRFB applications.

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“…The separator membrane is a key component of VRFBs as it affects the Coulombic efficiency, voltage efficiency, energy efficiency, power den-sity, and cycling life of the batteries. Three categories of separators have been previously evaluated to conduct charge-carrier ions and block vanadium ions, namely proton exchange membranes (PEMs) [5][6][7], anion exchange membranes (AEMs) [8][9][10], and nanofiltration membranes [11][12][13]. Compared with PEMs and nanofiltration membranes, AEMs are receiving increasing attention because of their low vanadium ion permeability due to the Coulombic repulsion between the cationic groups of the membranes and the vanadium cations.…”

Section: Introductionmentioning

confidence: 99%

Fluorinated poly(fluorenyl ether)s with linear multi-cationic side chains for vanadium redox flow batteries

Chen

Wang

et al. 2020

Sci. China Mater.

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The cationic group distribution along the polymeric backbones of anion exchange membranes (AEMs) has significant influence on their microscopic morphology and anion conductivity. To develop high-performance AEMs for vanadium redox flow batteries (VRFBs), a series of poly (fluorenyl ether) samples bearing di-and tri-quaternary ammonium side chains with similar ion exchange capacities (IECs) were synthesized by grafting cationic alkyl chains with tertiary amine-containing poly(fluorenyl ether) precursors. The experimental results indicate that the introduction of the multi-cationic side chains facilitates the formation of microphase-separated morphologies and enhances anion conductivity. Moreover, the number of spacer atoms between the quaternary ammonium groups on the side chains affects the water uptake of the membranes, thus complicating the relationship between the density of cationic group distribution and anion conductivity. The poly(fluorenyl ether)s with dicationic side chains and six spacing atoms (DQA-PFE-C6) showed the highest anion conductivity. A VRFB assembled with DQA-PFE-C6 exhibited a maximum power density of 239.80 mW cm −2 at 250 mA cm −2 , which is significantly higher than a VRFB assembled with Nafion 212. Therefore, side chain engineering is an effective chemical approach to enhance the properties of AEMs for VRFB applications.

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Tetra-alkylsulfonate functionalized poly(aryl ether) membranes with nanosized hydrophilic channels for efficient proton conduction

Cited by 22 publications

References 57 publications

Densely Quaternized Fluorinated Poly(fluorenyl ether)s with Excellent Conductivity and Stability for Vanadium Redox Flow Batteries

Densely Quaternized Fluorinated Poly(fluorenyl ether)s with Excellent Conductivity and Stability for Vanadium Redox Flow Batteries

Polyether Ether Ketone-Based Anion Exchange Membranes with Bis-imidazolium Cations for All-Vanadium Redox Flow Batteries

Fluorinated poly(fluorenyl ether)s with linear multi-cationic side chains for vanadium redox flow batteries

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