Proton-conducting materials based on metal-organic frameworks and protic salts as membranes for high temperature polymer electrolyte membrane fuel cells.

Polymer electrolyte membrane fuel cells (PEMFCs) are high-efficient and environmentally friendly power sources for a sustainable society. Particularly, high temperature PEMFCs operating between 100 and 200 °C are desirable. However, proton-conducting membranes with high proton conductivity under conditions of non-humidification and high temperatures are urgently needed. In this project we intend to develop novel composite membranes based on suitable metal-organic frameworks (MOFs) and protic salts. MOFs are novel crystalline materials with tunable porosity and consist of metal ions and organic linkers. The use of guest molecules to increase the proton conductivity has only recently begun by incorporating molecules (e.g. acids or imidazole) into MOF pores. On the other hand, protic salts, particularly protic ionic liquids and protic organic ionic plastic crystals, have emerged as exciting anhydrous proton conductors with high proton conductivity and high thermal stability. Therefore, suitable protic salts and MOFs will firstly be screened and designed. The corresponding composite membranes will then be prepared and characterized. Finally, selected composite membranes will be incorporated into high temperature PEMFCs and evaluated for their fuel cell performances. The optimized membranes derived from MOFs as the matrices and protic salts as the guest molecules are expected to be promising for high temperature PEMFC applications.