Silane-cross-linked polybenzimidazole with improved conductivity for high temperature proton exchange membrane fuel cells

Epoxides cross-linked hexafluoropropylidene polybenzimidazole membranes for application as high temperature proton exchange membranes

“…Comparing the IR spectra of F 6 PBI-R 3 membranes with that of F 6 PBI membrane, the band at around 3149 cm À1 , assigned to the stretching vibration of N-H groups in benzimidazole rings, became weaker; meanwhile, the absorption band at around 2875 cm À1 , assigned to the -CH 2 -groups in epoxide units of the cross-linker [24,32], became stronger as the increase in the crosslinking degree of the membranes. Moreover, the peak at 1104 cm À1 attributable to the stretching vibration of C-O groups appeared in the spectra of the cross-linked F 6 PBI membranes [38], which indicated the opening of the epoxide rings during the cross-linking reactions [31,33]. These results suggest the formation of cross-linked structure in the F 6 PBI-R 3 membrane as shown in Fig.…”

“…These membranes were all homogeneous and transparent with light yellow color. The membrane solubility in DMAc was used to estimate the occurrence and degree of the crosslinking [26,29,31,33,34]. As shown in Fig.…”

“…It is seen that the used macromolecule cross-linkers to the PBIs are aromatic polymers, which profit the PBI maintaining its stability. Compared to macromolecules, the small molecule reagents such as halide [24,29,30] and epoxide [31][32][33] are more frequently used cross-linkers for improvement of the membrane properties. In addition, several other methods were also explored to obtain cross-linked PBI membrane electrolytes, which include free radical polymerization of the side chain of cross-linker (i.e.…”

Proton conducting sulfonated poly (imide-benzimidazole) with tunable density of covalent/ionic cross-linking for fuel cell membranes

“…Imidazole moieties have been widely used to synthesize cross-linked polymeric materials by M A N U S C R I P T A C C E P T E D ACCEPTED MANUSCRIPT 4 amide-type linkages between the imidazole groups and the electrophilic cross-linking agents that contain two active groups such as epoxide [14] and halogen [15]. The resulted cross-linked membranes normally have very high chemical and physical stability.…”

In Situ Formed Phosphoric Acid/Phosphosilicate Nanoclusters in the Exceptional Enhancement of Durability of Polybenzimidazole Membrane Fuel Cells at Elevated High Temperatures

“…Composite PBI membranes with inorganic solid oxide additives such as SiO2 [22], HfO2 [23] or ionic liquid impregnated zeolite [24] have demonstrated improvements in the proton conductivity at elevated temperatures. Nevertheless, the long-term stability of inorganic-organic composite membranes is seldom studied.…”