Incorporation of benzimidazolium ionic liquid in proton exchange membranes ABPBI-H3PO4

Abstract

This paper presents the development of proton exchange membranes (PEM) from the incorporation of poly (2,5-benzimidazole) (ABPBI) in phosphoric acid (H3PO4) and ionic liquid (IL) 1-butyl-3- ethylbenzimidazolium dihydrogen phosphate (BEBzIm-H2PO4). We show structural, physicochemical and electrochemical characterization of synthesized IL and prepared membranes. The addition of IL in composite membranes of ABPBI-H3PO4 increases thermal stability. Also, the conductivity of membranes increases with temperature and the amount of absorbed mixture. Conductivity at a range of 10- 4 S/cm was achieved at 150 C by 50% IL and 50% phosphoric acid impregnation. This conducting composite membrane shows promise for operation in temperature proton exchange membrane fuel cells at working temperatures up to 100 C. © 2013 Elsevier B.V. All rights reserved.