Polymer electrolyte membranes for fuel cells

Current polymer electrolyte membranes (PEMs) for fuel cells are mostly based on perfluoro-sulfonated acids (PFSA), such as Nafion, Flemion, Aciplex, and Dow membranes. However, scientific and technical improvements are still needed to accommodate the increasing demands of fuel cell systems for specific applications. Higher performance, low cost, greater durability, better water management, and the ability to function at higher temperatures are some of the challenges that must be overcome before widespread commercial adoption of fuel cell technology occurs. Approaches and recent progress toward the development of polymer electrolyte membranes for fuel cells are reviewed. The newly developed/developing polymer membranes can be classified into four groups: modified PFSA membranes, alternative sulfonated polymers and their inorganic composite membranes, acid-base complex membranes, and ionic liquid-based gel-type proton conducting membranes. These polymer materials have a great variety of chemical structure and may be able to meet the targets for use in advanced fuel cell systems.