Polybenzimidazolium-Based Solid Electrolytes

• Published in: Macromolecular materials and engineering Vol. 296; no. 10; pp. 899 - 908
• Main Authors: Henkensmeier, Dirk, Kim, Hyoung-Juhn, Lee, Hye-Jin, Lee, Dong Hoon, Oh, In-Hwan, Hong, Seong-Ahn, Nam, Suk-Woo, Lim, Tae-Hoon
• Format: Journal Article
• Language: English
• Published: Weinheim WILEY-VCH Verlag 12-10-2011; WILEY‐VCH Verlag; Wiley
• Subjects: anionic exchange membranes; Applied sciences; Carboxylic acids; Chemical modifications; Chemical reactions and properties; Degradation; Diamines; Energy; Energy. Thermal use of fuels; Equipments for energy generation and conversion: thermal, electrical, mechanical energy, etc; Exact sciences and technology; Exchange resins and membranes; Exchanging; Forms of application and semi-finished materials; Fuel cells; Hydroxides; Ion exchangers; Membranes; NMR spectroscopy; Organic polymers; Physicochemistry of polymers; polybenzimidazole; polymer electrolyte fuel cells (PEFC); Polymer industry, paints, wood; Technology of polymers; Temperature effect; Polymer solid electrolyte; Bromocarbon; degradation; Thermal stability; Benzimidazole copolymer; Crosslinked copolymer; Anion exchange; Benzimidazole derivative copolymer; Aromatic copolymer; anionic exchange membranes; Metalation; Phenylene copolymer; polymer electrolyte fuel cells (PEFC); Solid electrolyte fuel cells; Electrical properties; Ionic conductivity; Xylene derivatives; Crosslinking; Experimental study; Open circuit voltage; membranes; Hydrolysis resistance; Chemical modification; Preparation; polybenzimidazole; Iodomethane; Anion exchange membrane; Methylation
• ISSN: 1438-7492; 1439-2054; 1439-2054
• DOI: 10.1002/mame.201100100

A series of methyl, benzyl, and mixed polybenzimidazolium halides was synthesised and characterised by NMR spectroscopy. Membranes were formed and ion exchanged with hydroxides. These membranes are of interest for use in potentially platinum‐free anionic exchange membrane fuel cells. Crosslinked membranes were obtained by the addition of α,α′‐dibromo‐p‐xylene to the casting solution. The ion conductivity of membranes was determined by impedance spectroscopy. A hydroxide conductivity of 29 mS · cm−1 at 26 °C and 58 mS · cm−1 at 60 °C was obtained. The thermal and hydrolytic stability was investigated and a pathway for hydrolytic degradation proposed. Hydroxide ions react at the 2 position, the intermediate carbinol opens to the amine–amide, and further degrades under chain scission to diamine and carboxylic acid.
Polybenzimidazolium hydroxide membranes are of interest for potentially platinum‐free anionic exchange membrane fuel cells. Hydroxide conductivities are 29 mS·cm−1 at 26°C and 58 mS·cm−1 at 60°C. Crosslinked membranes are obtained by the addition of α,α′‐dibromo‐p‐xylene to the casting solution. The thermal and hydrolytic stability is investigated and a pathway for hydrolytic degradation proposed.