ChemInform Abstract: Acid‐Doped Polybenzimidazoles: A New Polymer Electrolyte.

Abstract

Acid-Doped Polybenzimidazoles: A New Polymer Electrolyte.-The proton conductivity and MeOH vapor permeability are measured for polybenzimidazole (PBI) films doped with H3PO4 and the applicability of the films as potential polymer electrolytes for hydrogen/air and direct MeOH fuel cells is studied. Long-term tests show that the PBI electrolyte is stable at elevated temp. even in the presence of H2, O2, and Pt. A H2/O2 cell with the PBI-based electrolyte and Pt/C electrodes was successfully operated at 200 mA/cm2 for over 200 h without decay of the performance. The max. power observed for an unoptimized cell was 0.25 W/cm2 at 700 mA/cm2. The MeOH/O2 fuel cell with PBI-H3PO4 membrane, Pt-Ru anode, and Pt black cathode produces over 0.1 W/cm2 at 250-500 mA/cm2. The low MeOH permeability of the electrolyte reduces the adverse effects of MeOH crossover. -(WAINRIGHT, J. S.; WANG, J.-T.; WENG, D.; SAVINELL, R. F.; LITT, M.; J. Electrochem. Soc. 142 (1995) 7, L121-L123; Dep. Chem. Eng., Case West. Reserve Univ., Cleveland, OH 44106-7217, USA; EN)

Influence of the Teflon loading in the gas diffusion layer of PBI-based PEM fuel cells

“…This material has certain advantages such as high proton conductivity when impregnated with a non-volatile acid (phosphoric acid), and exceptional thermal and chemical stability. These properties have driven the rapid development of PBI-based PEMFC systems since 1995, when it was first proposed by Savinell and co-workers [5].…”

Pt–MoOx-carbon nanotube redox couple based electrocatalyst as a potential partner with polybenzimidazole membrane for high temperature Polymer Electrolyte Membrane Fuel Cell applications

“…Phosphoric acid doped PBI membrane as proton conducting ionomer (where PBI supports the phosphoric acid for proton conduction) for PEMFC applications has gained considerable attention in recent years mainly because of the benefits of the reduced CO poisoning of Pt due to the possible high cell operating temperature and simplification of the system engineering due to the ability of the membrane to display high conductivity even in the absence of cell humidification [23][24][25][26]. The PBI matrix acts as the relatively thermally stable containment for phosphoric acid and the proton movement is facilitated by the phosphoric acid phase.…”

Methyl phosphate formation as a major degradation mode of direct methanol fuel cells with phosphoric acid based electrolytes

“…Lifetimes >18,000 h have been repeatedly reported under steady state as well as dynamic operation [5e8]. This type of membrane was, however, originally suggested as electrolyte material for direct methanol PEM fuel cells almost 20 years ago [9]. In this connection, the very low permeability of gaseous methanol is strongly advantageous since it reduces the adverse effects of methanol crossover observed for conventional polymer electrolytes [9].…”