Proton conduction mechanism in H3PO4 imbibed PEMs. The effect of chemical structure and steam

摘要

In recent years, there has been intense interest in polymer electrolyte membrane fuel cell (PEMFC) for transportation and other portable applications (1). Typically, the electrolyte used is Nafion (DuPont), whose need of hydration limits up the operating temperature. Recent progress has focused on the need to develop fuel cells that operate above 100°C (2, 3), due to many and well known advantages concerning the enhancement of the reaction kinetics, the facility on the feed gas, as well as simplifications on the overall system design. The existing state of the art technology is based on materials that combine acid-base interactions (4, 5). Poly(benzimidazole), PBI, proposed by Aharoni and Litt (6) and Wainright et al (7) has been widely studied with various strong acids as a promising electrolyte. PBI exhibits high acid uptake and high ionic conductivities (7, 8, 9,10,11, 12) and has been tested as polymer electrolyte in high temperature PEMFCs (13,14).