Proton-conducting membranes based on poly(2,5-benzimidazole) (ABPBI) and phosphoric acid prepared by direct acid casting

✍ Scribed by Juan Antonio Asensio; Salvador Borrós; Pedro Gómez-Romero

• Publisher: Elsevier Science
• Year: 2004
• Tongue: English
• Weight: 104 KB
• Volume: 241
• Category: Article
• ISSN: 0376-7388
• DOI: 10.1016/j.memsci.2004.03.044

✦ Synopsis

We report the preparation of phosphoric acid doped poly(2,5-benzimidazole) (ABPBI) membranes for PEMFC by simultaneously doping and casting from a poly(2,5-benzimidazole)/phosphoric acid/methanesulfonic acid (MSA) solution. The evaporation of MSA yields a very homogeneous membrane having a better controlled composition, avoiding the use of solvent-intensive procedures. Membranes have been prepared with contents of up to 3.0H 3 PO 4 molecules per ABPBI repeating unit. These membranes achieve a maximum conductivity of 1.5 × 10 -2 S cm -1 at temperatures as high as 180 • C in dry conditions. These ABPBI membranes are more conveniently prepared than those conventionally formed and doped in separate steps while featuring comparable conductivities (ABPBI × 2.7H 3 PO 4 prepared by the soaking method showed a conductivity of 2.5 × 10 -2 S cm -1 at 180 • C in dry conditions).