Polybenzimidazole/Acid Complexes as High-Temperature Membranes

Mader, J. A.; Xiao, Liuling; Schmidt, Thomas J.; Benicewicz, Brian C.

doi:10.1007/12_2007_129

Cited by 138 publications

(180 citation statements)

References 100 publications

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“…A large body of the work on polybenzimidazole derivatives and copolymers/ blends/fillers as high temperature fuel cell membranes was recently reviewed. 22 Some of the perceived problems with PBI include low molecular weight (inherent viscosities (IVs) of 0.5-0.8 dL g -1 ), low phosphoric acid loading (typically 6-10 mol of phosphoric acid per mole polymer repeat unit [moles PA/PBI]), phosphoric acid retention during operation, and membrane durability. The vast majority of PBI research has been done on the commercially available meta-PBI or AB-PBI structures.…”

Section: Introductionmentioning

confidence: 99%

Sulfonated Polybenzimidazoles for High Temperature PEM Fuel Cells

2010

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High molecular weight, highly PA-doped s-PBI membranes have been developed with robust mechanical properties and excellent proton conductivities (>0.1 S cm -1 ) at elevated temperatures (>100°C). These membranes show high PA loadings of 30-35 mol PA/PBI, and average tensile stress and strain of 0.804 MPa and 69.64%, respectively. Proton conductivities were dependent on the acid doping level and measured between 0.1 and 0.25 S cm -1 at 180°C, a pronounced increase over most phosphoric acid-doped sulfonated PBI membranes to date. Preliminary fuel cell testing with hydrogen fuel and air or oxygen oxidants was performed at temperatures greater than 100°C without external feed gas humidification and show excellent performance (0.62-0.68 V at 0.2 A cm -2 and 160°C, hydrogen/air; 0.69-0.76 V at 0.2 A cm -2 and 160°C, hydrogen/oxygen). Initial performance stability studies were conducted for ∼3000 h and indicate great promise as high temperature membranes, with a degradation rate of 30 μV h -1 .

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Section: Introductionmentioning

confidence: 99%

Sulfonated Polybenzimidazoles for High Temperature PEM Fuel Cells

2010

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“…To achieve this, a focus of research needs to be on developing improved membrane materials [57]. A summary of PBI properties is provided by Mater [62].…”

Section: High Temperature Polymer Electrolyte Membranesmentioning

confidence: 99%

Catalyst, Membrane, Free Electrolyte Challenges, and Pathways to Resolutions in High Temperature Polymer Electrolyte Membrane Fuel Cells

2017

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High temperature polymer electrolyte membrane fuel cells (HT-PEMFCs) are being studied due to a number of benefits offered versus their low temperature counterparts, including co-generation of heat and power, high tolerance to fuel impurities, and simpler system design. Approximately 90% of the literature on HT-PEM is related to the electrolyte and, for the most part, these electrolytes all use free phosphoric acid, or similar free acid, as the ion conductor. A major issue with using phosphoric acid based electrolytes is the free acid in the electrodes. The presence of the acid on the catalyst sites leads to poor oxygen activity, low solubility/diffusion, and can block electrochemical sites through phosphate adsorption. This review will focus on these issues and the steps that have been taken to alleviate these obstacles. The intention is this review may then serve as a tool for finding a solution path in the community.

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“…Proton conductivity (where protons can freely move around in the ion exchange membrane via the hopping mechanism [27]) is one of the most important characteristics of ion exchange membranes when evaluating fuel cell performance [14,28]. As such, the proton conductivity of the prepared films was compared to that of commercially available Nafion, a sulfonated tetrafluoroethylene-based membrane.…”

Section: Proton Conductivity Of S-pbi S-opbi and Sc-opbi Membranesmentioning

confidence: 99%

“…In this study, we have employed PBI, which is very cheap and exhibits thermally and chemically stable properties under various conditions [6,[14][15][16][17]. PBI has a heterocyclic benzimidazole ring with an amphoteric character, which can be easily modified with strong acids (such as phosphoric acid and/or sulfuric acid) to be used as an ionic conductive membrane [3,[18][19][20].…”

Section: Introductionmentioning

confidence: 99%

Preparation of Polybenzimidazole-Based Membranes and Their Potential Applications in the Fuel Cell System

Hwang

Kim

et al. 2014

Energies

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Abstract:Various polybenzimidazole (PBI)-based ion-exchange films were prepared and thoroughly characterized by Fourier transform infrared (FT-IR) spectroscopy, proton conductivity, and water uptake for possible use as fuel cell membranes. Upon the increase in the flexibility of the PBI-based polymer films (e.g., poly(oxyphenylene benzimidazole) (OPBI) and sulfonated OPBI (s-OPBI)), the membranes exhibited slightly improved proton conductivity, but significantly increased dimensional changes. To reduce the dimensional changes (i.e., increase the stability), the cross-linking of the polymer films (e.g., cross-linked OPBI (c-OPBI) and sulfonated c-OPBI (sc-OPBI)) was accomplished using phosphoric acid. Interestingly, the sc-OPBI membrane possessed a greatly increased proton conductivity (0.082 S/cm), which is comparable to that of the commercially available Nafion membrane (0.09 S/cm), while still maintaining slightly better properties regarding the dimensional change and water uptake than those of the Nafion membrane.

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Polybenzimidazole/Acid Complexes as High-Temperature Membranes

Cited by 138 publications

References 100 publications

Sulfonated Polybenzimidazoles for High Temperature PEM Fuel Cells

Sulfonated Polybenzimidazoles for High Temperature PEM Fuel Cells

Catalyst, Membrane, Free Electrolyte Challenges, and Pathways to Resolutions in High Temperature Polymer Electrolyte Membrane Fuel Cells

Preparation of Polybenzimidazole-Based Membranes and Their Potential Applications in the Fuel Cell System

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