Structured inorganic-polymer hybrid membranes for fuel cell application in the operating temperature range of 25 - 220°C

Fuel cells (FC) technology is a promising alternative to combustion-based energy sources for mobile and domestic applications. Nowadays, high temperature polymer electrolyte membrane FCs (HT-PEMFCs) can operate effectively from 120 to 200°C. Their application in an extended operation temperature region can be achieved by suitable structural and/or compositional modifications. In this regard, the goal of our project is the development of phosphoric acid (PA) containing HT‑PEMFCs based on a structured organic-inorganic proton conducting hybrid-membrane. They should extend their operation temperature from room temperature up to 220°C. In addition, these structured hybrid membranes is expected to exhibit enhanced thermal and mechanical stability. To do this, novel heat-resistant ion-pair polymers, which can strongly interact with PA will be utilized. To improve PA retention in the membrane, polymer modification with permanently charged anion-exchanging functional groups is foreseen. To enhance the mechanical and thermal stability, inorganic proton conductors will be implemented in the polymer membrane. Applying different alignment techniques, the inorganic phase consisting of anisotropic particles (fibers or layered structures) will be oriented perpendicular to the membrane plane. The local contacts between the aligned structures are expected to be 

improved, and hence the decrease in the lengths of the proton paths between the electrodes is expected to produce enhanced conductivities. Electrode binders will be a matter of innovation as well. Phosphonated polymers have demonstrated good and stable performance in HT-PEMFC applications. In addition to such ionomers, novel catalyst binders based on the new polyelectrolytes will be tested and optimized for the anode and cathode sides of the FC. The use of similar materials in the membrane and electrodes may have positive impact on conductivity and smooth migration of the protons from the gas-diffusion-electrodes (GDEs) to the membrane.

Using ion-pair technology, MEAsureD will be able to reduce the platinum metal group (PGM) content of the FC stack by employing new type of catalysts and reduce the cost and the weight. Moreover, high stable ionomers and membranes under dry conditions and high durability catalysts, catalyst support and membranes will be studied to improve MEA’s performance. Lastly, the environmental impact of the developed technology (recyclability and circularity of the materials) as well as the applicability to other transport sectors, such as, maritime, aviation and railway will be researched.