Preparation and proton conductivity of poly(<i>N</i>‐methylbenzimidazole) doped with acid

Pu, Hongting; Gai-hua, Liu

doi:10.1002/pat.527

Cited by 9 publications

(7 citation statements)

References 18 publications

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“…Pu and Liu [113][114][115] prepared poly(Nmethylbenzimidazole) and poly(N-ethylbenzimidazole). Interestingly, when methyl and ethyl groups are introduced on the imidazole moiety, the obtained N-substituted PBI showed high acid-doping levels and therefore high proton conductivity.…”

Section: Pbi Modified By Post-polymerization Substitution 2141 N-mentioning

confidence: 99%

High temperature proton exchange membranes based on polybenzimidazoles for fuel cells

Jensen

Savinell

et al. 2009

Progress in Polymer Science

1,235

852

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This article appeared in a journal published by Elsevier. The attached copy is furnished to the author for internal non-commercial research and education use, including for instruction at the authors institution and sharing with colleagues.Other uses, including reproduction and distribution, or selling or licensing copies, or posting to personal, institutional or third party websites are prohibited. To achieve high temperature operation of proton exchange membrane fuel cells (PEMFC), preferably under ambient pressure, acid-base polymer membranes represent an effective approach. The phosphoric acid-doped polybenzimidazole membrane seems so far the most successful system in the field. It has in recent years motivated extensive research activities with great progress. This treatise is devoted to updating the development, covering polymer synthesis, membrane casting, physicochemical characterizations and fuel cell technologies. To optimize the membrane properties, high molecular weight polymers with synthetically modified or N-substituted structures have been synthesized. Techniques for membrane casting from organic solutions and directly from acid solutions have been developed. Ionic and covalent cross-linking as well as inorganic-organic composites has been explored. Membrane characterizations have been made including spectroscopy, water uptake and acid doping, thermal and oxidative stability, conductivity, electro-osmotic water drag, methanol crossover, solubility and permeability of gases, and oxygen reduction kinetics. Related fuel cell technologies such as electrode and MEA fabrication have been developed and high temperature PEMFC has been successfully demonstrated at temperatures of up to 200• C under ambient pressure. No gas humidification is mandatory, which enables the elimination of the complicated humidification system, compared with Nafion cells. Other operating features of the PBI cell include easy control of air flow rate, cell temperature and cooling. The PBI cell operating at above 150• C can tolerate up to 1% CO and 10 ppm SO 2 in the fuel stream, allowing for simplification of the fuel processing system and possible integration of the fuel cell stack with fuel processing units. Long-term durability with a degradation rate of 5 V h −1 has been achieved under continuous operation with hydrogen and air at 150-160• C. With load or thermal cycling, a performance loss of 300 V per cycle or 40 V h −1 per operating hour was observed. Further improvement should be done by, e.g. optimizing the thermal and chemical stability of the polymer, acid-base interaction and acid management, activity and stability of catalyst and more importantly the catalyst support, as well as the integral interface between electrode and membrane.

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Section: Pbi Modified By Post-polymerization Substitution 2141 N-mentioning

confidence: 99%

High temperature proton exchange membranes based on polybenzimidazoles for fuel cells

Jensen

Savinell

et al. 2009

Progress in Polymer Science

1,235

852

View full text Add to dashboard Cite

show abstract

“…The factors that affect the acid doping ability of PBI/ H 3 PO 4 membranes have been studied before [32,33]. The concentration of the acid solution and doping time are the two main methods to adjust the acid doping level.…”

Section: Doping Ability Of Phosphoric Acid In Crosslinked Membranesmentioning

confidence: 99%

Preparation and Characterisation of Proton Exchange Membranes Based on Crosslinked Polybenzimidazole and Phosphoric Acid

Guan

Jin

et al. 2010

Fuel Cells

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Crosslinked polybenzimidazole (PBI) was synthesised via free radical polymerisation between N‐vinylimidazole and vinylbenzyl substituted PBI. The degree of crosslinking increases with increasing content of the crosslinker. The phosphoric acid doping behaviour, mechanical properties, proton conductivity and acid migration stability of crosslinked PBI and linear PBI are discussed. The results show that the acid doping ability decreases with increasing degree of crosslinking of PBI. The introduction of N‐vinylimidazole in PBI is beneficial to its oxidation stability. The mechanical stability of crosslinked PBI/H3PO4 membrane is better than that of linear PBI/H3PO4 membrane. The proton conductivity of the acid doped membranes can reach ∼10–4 S cm–1 for crosslinked PBI/H3PO4 composite membranes at 150 °C. The temperature dependence of proton conductivity of the acid doped membranes can be modelled by an Arrhenius relation. The proton conductivity of crosslinked PBI/H3PO4 composite membranes is a little lower than that of linear PBI/H3PO4 membranes with the same acid content. However, the migration stability of H3PO4 in crosslinked PBI/H3PO4 membranes is improved compared with that of linear PBI/H3PO4 membranes.

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“…The factors that affect the acid doping level of PBI-ph/H 3 PO 4 membranes have been studied before. 30,31 The higher acid concentration and longer doping time result in higher acid doping level in the membranes, which can also be found in Fig. 8.…”

Section: Solubility and Thermal Stability Of Pbi-cnmentioning

confidence: 60%

Synthesis and properties of poly[2,2′-(4,4′-(2,6-bis(phenoxy) benzonitrile))-5,5′-bibenzimidazole] for proton conducting membranes in fuel cells

Guan

Wan

2011

Polym. Chem.

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Preparation and proton conductivity of poly(N‐methylbenzimidazole) doped with acid

Cited by 9 publications

References 18 publications

High temperature proton exchange membranes based on polybenzimidazoles for fuel cells

High temperature proton exchange membranes based on polybenzimidazoles for fuel cells

Preparation and Characterisation of Proton Exchange Membranes Based on Crosslinked Polybenzimidazole and Phosphoric Acid

Synthesis and properties of poly[2,2′-(4,4′-(2,6-bis(phenoxy) benzonitrile))-5,5′-bibenzimidazole] for proton conducting membranes in fuel cells

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