Benzimidazole grafted polybenzimidazole cross-linked membranes with excellent PA stability for high-temperature proton exchange membrane applications

Tian, Xue; Wang, Shuang; Li, Jinsheng; Liu, Fengxiang; Wang, Xu; Chen, Hao; Wang, Di; Ni, Hongzhe; Wang, Zhe

doi:10.1016/j.apsusc.2018.09.170

Cited by 70 publications

(34 citation statements)

References 43 publications

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“…In general, the chemical crosslinking of AEMs could be classified into two methods: using an extra monomer with crosslinkable functional groups in the polymerization reaction or reacting linear polymers with crosslinking reagents . In both the cases, the crosslinking groups do not practically contribute to the hydroxide ion conduction.…”

Section: Introductionmentioning

confidence: 99%

Effect of crosslinking on the properties of partially fluorinated anion exchange membranes

Koronka

Mahmoud

Miyatake

2019

J. Polym. Sci. Part A: Polym. Chem.

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A series of crosslinked, ammonium-functionalized, and partially fluorinated copolymers have been prepared and evaluated as anion exchange membranes. In order to investigate the effect of crosslinking on the membrane properties, precursor copolymers containing chloromethyl groups were crosslinked with various aliphatic diamines followed by quaternization with monoamines. Crosslinking was effective in lowering water absorbability at no expense of high hydroxide ion conductivity of the membranes. By tuning the degree of crosslinking (20 mol %) and crosslinker chain length (C6 and C8), the highest ion conductivity of 73 mS/cm (at 80 C in water) was achieved. Furthermore, alkaline stability of the membranes was also improved by the crosslinking; the remaining ion conductivity after the stability test (in 1 M potassium hydroxide at 80 C) was 8.2 mS/cm (after 1000 h) for the C6 crosslinked membrane and 1 mS/cm (after 500 h) for the uncrosslinked membrane, respectively. The ammonium groups attached with the crosslinkers seemed more alkaline stable than the uncrosslinked benzyltrimethylammonium groups, while the polymer main chain was intact under the harsh alkaline conditions.

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Section: Introductionmentioning

confidence: 99%

Effect of crosslinking on the properties of partially fluorinated anion exchange membranes

Koronka

Mahmoud

Miyatake

2019

J. Polym. Sci. Part A: Polym. Chem.

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“…Today, energy is consumed directly and indirectly in order to continue technological developments and to maintain the opportunities offered in our lives. However, environmental problems, ecosystem degradation, global warming, air and water pollution, and the increasing population rate against the lack of energy have increased the need for environmentally friendly clean energy sources . Polymer electrolyte membrane fuel cells (PEMFCs) are the energy conversion devices, which are frequently mentioned in recent years, because they are efficient, economical, quiet, and environmentally friendly.…”

Section: Introductionmentioning

confidence: 99%

“…However, environmental problems, ecosystem degradation, global warming, air and water pollution, and the increasing population rate against the lack of energy have increased the need for environmentally friendly clean energy sources. 1 Polymer electrolyte membrane fuel cells (PEMFCs) are the energy conversion devices, which are frequently mentioned in recent years, because they are efficient, economical, quiet, and environmentally friendly. Fuel cells are the systems that convert alternative energy sources into efficient energy.…”

Section: Introductionmentioning

confidence: 99%

“…2 The role of PEMs, which are one of the most important part of PEMFCs, is to ensure the proton transport between the electrodes and to prevent the mixture of fuel and oxidant. 1 One of the major problems that need to be overcome in order to evolve the stability and efficiency of fuel cells is water management. The role of the GDL in the PEM fuel cells is to create a pore path for the reactant and to remove the water as a result of the reaction.…”

Section: Introductionmentioning

confidence: 99%

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PEMFC catalyst layer modification with the addition of different amounts of PDMS polymer in order to improve water management

Ungan

Yurtcan

2019

Int J Energy Res

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Summary The balance between preventing water flooding and adequate humidification of the membrane will provide a significant contribution to proton exchange membrane (PEM) fuel cell performance. For this purpose, polydimethylsiloxane (PDMS), a hydrophobic polymer, was added to the catalyst layer of the fuel cell at different amounts including 5, 10, and 20 wt%. The performances of the fuel cells including PDMS were compared with the commercial catalyst. Morphological changes of the gas diffusion electrodes (GDEs) were confirmed by using scanning electron microscopy (SEM). Fourier transformation infrared spectroscopy (FTIR) was used to determine the functional groups and contact angle measurements were used to determine the hydrophobic characteristics. Cyclic voltammetry (CV), impedance, and oxygen reduction reaction (ORR) analysis were performed for electrochemical characterization and degradation behaviors. In situ PEM fuel cell tests were performed in order to define the best catalyst ink combination that include PDMS. The results of the cyclic voltammograms proved that the electrochemical surface area (ECSA) increased with the increasing amount of PDMS. The highest ECSA of 53.84 m2 g−1 was calculated for catalyst ink with 20‐wt% PDMS. The lowest ECSA loss after aging was observed in the catalyst ink with 10‐wt% PDMS. As a result, the catalyst layer having 10‐wt% PDMS showed the best polymer electrolyte membrane fuel cells (PEMFC) performance.

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“…Compared to branching, cross-linking is an effective way to improve mechanical strength because it strengthens the interactions among the polymer chains. Recently, cross-linking has been widely explored in PA/PBI membranes for HT-PEMFCs, and improved properties have been achieved compared to those of linear PBI membranes [12,[24][25][26][27][28]. Based on the advantages of cross-linking and branching, applying both methods to one membrane can enhance performance.…”

Section: Introductionmentioning

confidence: 99%

Synthesis and Properties of Phosphoric-Acid-Doped Polybenzimidazole with Hyperbranched Cross-Linkers Decorated with Imidazolium Groups as High-Temperature Proton Exchange Membranes

Gao

Wang

et al. 2020

Polymers

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Highly phosphoric-acid (PA)-doped polybenzimidazole (PBI) membranes exhibit good proton conductivity at high temperatures; however, they suffer from reduced mechanical properties and loss of PA molecules due to the plasticity of PA and the weak interactions between PA and benzimidazoles, especially with the absorption of water. In this work, a series of PBIs with hyperbranched cross-linkers decorated with imidazolium groups (ImOPBI-x, where x is the weight ratio of the hyperbranched cross-linker) as high-temperature proton exchange membranes are designed and synthesized for the first time. We observe how the hyperbranched cross-linkers can endow the membranes with improved oxidative stability and acceptable mechanical performance, and imidazolium groups with strong basicity can stabilize the PA molecules by delocalization and hydrogen bond formation to endow the membranes with an enhanced proton conductivity and a decreased loss of PA molecules. We measured a high proton conductivity of the ImOPBI-x membranes, ranging from 0.058 to 0.089 S cm−1 at 160 °C. In addition, all the ImOPBI-x membranes displayed good mechanical and oxidative properties. At 160 °C, a fuel cell based on the ImOPBI-5 membrane showed a power density of 638 mW cm−2 and good durability under a hydrogen/oxygen atmosphere, indicating its promising use in anhydrous proton exchange membrane applications.

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Benzimidazole grafted polybenzimidazole cross-linked membranes with excellent PA stability for high-temperature proton exchange membrane applications

Cited by 70 publications

References 43 publications

Effect of crosslinking on the properties of partially fluorinated anion exchange membranes

Effect of crosslinking on the properties of partially fluorinated anion exchange membranes

PEMFC catalyst layer modification with the addition of different amounts of PDMS polymer in order to improve water management

Synthesis and Properties of Phosphoric-Acid-Doped Polybenzimidazole with Hyperbranched Cross-Linkers Decorated with Imidazolium Groups as High-Temperature Proton Exchange Membranes

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