The membrane is one of the very central polymer electrolyte membrane fuel cell components. At the same time it must conduct protons and inhibit transport of electrons and cross-over of reactant gases. Additionally, degradation effects have to be small to ensure a long lifetime. While traditionally consisting of pure Nafion, up to date membranes contain nanofiber reinforcements and radical scavenger packages to decrease degradation effects. Thus, seminal membranes are multi-layer, multi-component structures.

In the state of the art, membrane electrode assemblies (MEA) are manufactured as catalyst coated membranes (CCMs). To form a CCM, electrodes are deposited either by the decal method, or by another deposition method.

In this talk we present a novel approach for MEA manufacturing. In the so called ‘direct membrane deposition’ (DMD) approach, liquid ionomer is deposited on the catalyst layers of two gas diffusion electrodes which are successively dried and pressed together to form an MEA. Interestingly, this approach enabled power densities more than two times higher than traditional CCM based approaches which are commercially available [1]. Also this approach allows for a simple fabrication of thin multi-layer membranes and improves the water management [2]. DMD applied to low Pt loading electrodes revealed very high power densities per gram Pt of up to 88 kW/g Pt [3]. An analysis of the underlying reasons for the improved performance values revealed a small influence of membrane resistance but mainly an influence in mass transport and charge transfer phenomena [4,5].

In this talk we highlight our latest developments in the field of DMD based manufacturing and give an insight on degradation and durability aspects.

References:

[1] M. Klingele, M. Breitwieser, R. Zengerle, S. Thiele, J. Mater. Chem. A 3 (2015) 11239–11245.

[2] M. Breitwieser, R. Moroni, J. Schock, M. Schulz, B. Schillinger, F. Pfeiffer, R. Zengerle, S. Thiele, Int J Hydrogen Energ 41 (2016) 11412–11417.

[3] M. Breitwieser, M. Klingele, B. Britton, S. Holdcroft, R. Zengerle, S. Thiele, Electrochem. Commun. 60 (2015) 168–171.

[4] M. Klingele, B. Britton, M. Breitwieser, S. Vierrath, R. Zengerle, S. Holdcroft, S. Thiele, Electrochemistry Communications 70 (2016) 65–68.

[5] S. Vierrath, M. Breitwieser, M. Klingele, B. Britton, S. Holdcroft, R. Zengerle, S. Thiele, J. Power Sources 326 (2016) 170–175.170 - 175.