Freestanding Catalyst Layers: A Novel Electrode Fabrication Technique for PEM Fuel Cells via Electrospinning

To propel the commercial success of fuel cells, increased Pt catalyst utilization is preeminent. To achieve this, advanced 3D scaffold electrode architecture with controllable porosity, thickness etc., should be developed. Here, we present a novel technique for fabrication of electrode structures via electrospinning which is not only tailorable, but inexpensive and scalable. The structure is freestanding and contains carbon nanotubes enforced carbon nanofibers which give the electrode its structure. Pt is decorated on the surface of the fiber structures via impregnation of Pt precursor and successive reduction. The electrode structure is hot-pressed by inserting it between gas diffusion layer (GDL) and membrane to form the cathode. The novel fabrication technique is versatile and can be used to prepare electrodes of different morphologies. In this work, we demonstrate the technique by preparing a highly porous network which shows a very high Pt utilization of approx. 90% for a loading of 0.3 mg Pt cm^-2. In comparison, a standard electrode prepared via hot-spray technique has a catalyst utilization of 60\% for the same loading.