Project Details
Projekt
Proton conducting and hydrophilic coordination polymers - synthesis, spectroscopic investigation and incorporation in fuel cell membranes
Subject Area
Solid State and Surface Chemistry, Material Synthesis
Physical Chemistry of Solids and Surfaces, Material Characterisation
Physical Chemistry of Solids and Surfaces, Material Characterisation
Term
from 2016 to 2022
Project identifier
Deutsche Forschungsgemeinschaft (DFG) - Project number 316657024
Proton conducting materials are a key component in fuel cells, which use hydrogen and oxygen to produce electricity and heat. The state-of-the-art material currently employed is the perfluorosulfonic acid ionomer Nafion, but its use is limited to high humidity values and, hence, to low temperatures (< 80 °C). New functional materials that can be used at higher temperatures, preferably under anhydrous conditions, are needed. Coordination polymers (CPs) are one very promising class of compounds suitable for this kind of applications. The scope of this project is the creation, understanding, and exploitation of proton-conducting coordination polymers (PCCPs) in fuel cell composite membranes of various compositions and the real-time in-situ monitoring of humidity and proton conductivity. Special emphasis will be placed on introducing -PO3H2 or -PO3H- groups and additional proton carriers to create materials with a high and stable proton conductivity. To develop a better understanding for the structure-property relationship and the role of water molecules and particle size of the CPs, the proton conducting mechanism under various relative humidity values will be studied in detail. To investigate their possible application in fuel cells, composite polymer membranes which contain PCCPs of various particle sizes will be fabricated and tested. Since the relative humidity has a strong influence on the proton conduction a sensor will be developed to monitor in situ the humidity in the cell membrane under load. To accomplish this, we brought together the research groups of Norbert Stock (Kiel), Michael Wark (Oldenburg), and Michael Tiemann (Paderborn), synergistically combining their complementary skills in synthesis/characterization of coordination polymers, proton conduction in composite membranes, and sensing. The PCCPs will be synthesized in the Stock group. For selected systems synthetic strategies towards PCCP nanoparticles with controlled particle sizes will be established. The Tiemann group will carry out in-depth temperature-dependent impedance spectroscopic investigations to study the proton conduction pathway and will also fabricate a fringing electric field (FEF) sensing element. This sensor element will facilitate in-situ impedance measurements on the composite membranes which will be prepared and tested in detail by the Wark group. Various polymers containing sulfonate and phosphonate groups as well as acid-base polymer blends will be employed in the formation of such composite membranes and, in addition, membranes consisting of consecutive PCCPs and polymer layers will be studied. In close collaboration with the EWE Research Institute NEXT ENERGY selected composite membranes will be used to fabricate membrane-electrode assemblies. These will be applied in a test stand operating at realistic fuel cell conditions.
DFG Programme
Priority Programmes
