This chapter is focused in the application of benzimidazole, mainly in the form of poly[2,2′-(m-phenylene)-5,5′-bisbenzimidazole] (PBI) and poly(2,5-benzimidazole) (ABPBI), in the fuel cell technology. A short introduction is given of the fuel cell principles, explaining both the theory and the high importance of this technology. PBI and ABPBI are used in a certain type of fuel cells: the polymer electrolyte fuel cells and are key materials in the composition of some of the electrolyte membranes used. Commercially available membranes composed of PBI are indicated in order to give an overview of their potential performance. The synthesis of the polymers is explained. Moreover, the preparation of the different kinds of membranes, both in proton exchange membrane fuel cells (PEMFCs) and anion exchange membrane fuel cells (AEMFCs) is studied. A deep description is given about the properties that make this family of compounds so interesting for the fuel cell technology as well as an how these polymers have been characterized with the corresponding analysis. The comparison with other ion exchange membranes is also discussed. Special attention will be given to the state of the art of different kinds of PBI/ABPBI fuel cell electrolyte membranes, in which our group and others are working nowadays.
Part of the book: Chemistry and Applications of Benzimidazole and its Derivatives