polymer electrolyte; fuel cell; two phase flow; surface functionalization; gas diffusion layer; graft copolymerization; patterned wettability
Forner-Cuenca A., Manzi-Orezzoli V., Kristiansen P.M., Gubler L., Schmidt T.J., Boillat P. (2017), Mask-assisted electron radiation grafting for localized through-volume modification of porous substrates: influence of electron energy on spatial resolution, in Radiation Physics and Chemistry
Forner-Cuenca A., Manzi-Orezzoli V., Biesdorf J., Kazzi M.E., Streich D., Gubler L., Schmidt T.J., Boillat P. (2016), Advanced water management in PEFCs: Diffusion layers with patterned wettability: I. Synthetic Routes, Wettability Tuning and Thermal Stability, in Journal of the Electrochemical Society
, (8), 788-801.
Forner-Cuenca A., Biesdorf J., Lamibrac A., Manzi-Orezzoli V., Büchi F.N., Gubler L., Schmidt T.J., Boillat P. (2016), Advanced water management in PEFCs: Diffusion layers with patterned wettability: II. Measurement of capillary pressure characteristic with neutron and synchrotron imaging, in Journal of the Electrochemical Society
, 163(9), 1038-1048.
Forner-Cuenca A., Biesdorf J., Manzi-Orezzoli V., Gubler L., Schmidt T. J., Boillat P. (2016), Advanced Water Management in PEFCs: Diffusion Layers with Patterned Wettability: III. Operando Characterization with Neutron Imaging, in Journal of The Electrochemical Society
, 163(13), F1389-F1398.
Forner-Cuenca Antoni, Biesdorf Johannes, Gubler Lorenz, Kristiansen Per Magnus, Schmidt Thomas Justus, Boillat Pierre (2015), Engineered Water Highways in Fuel Cells: Radiation Grafting of Gas Diffusion Layers, in ADVANCED MATERIALS
, 27(41), 6317-6322.
In this project, we propose a novel method for the synthesis of porous materials with a defined spatial pattern of wettability (hydrophobic and hydrophilic) regions. Such materials could be used in polymer electrolyte fuel cells (PEFCs) to develop advanced water management strategies such as the humidification of the cell by injection of liquid water and the mitigation of the effect of water accumulation on gas transport. The improved water management in PEFCs is expected to yield significant benefits in terms of cost reduction and extended durability.The proposed synthesis method is based on the surface modification of the materials fluoropolymer coatings by radiation-induced graft copolymerization. The base material with a base hydrophobic coating is irradiated according to defined patterns (using masks). By further impregnation in a grafting solution, the surface of the coating in the exposed regions is modified to become hydrophilic. The study and development of this synthesis method will benefit from the expertise existing in the PSI Electrochemisty Laboratory in the field of radiation-induced graft copolymerization, a method which has been extensively used in the last year for the synthesis of fuel cell membrane materials.The project will focus on the synthesis and characterization of material samples based on the proposed method. The study of the synthesis will include the evaluation of the different aspects of the proposed generic method, including the choice of base polymer coating, the type of irradiation and the choice of compounds for the surface modification. The sample characterization will include standard contact angle measurements as well as locally resolved measurement based on imaging methods such as energy-dispersive X-ray spectroscopy (EDX), neutron radiography and synchrotron X-ray tomography.Finally, the study will be completed by the in situ characterization of selected samples in operating PEFCs: the liquid water distribution will be measured using neutron imaging and the effect of water accumulation on cell performance will be evaluated using the helox pulse method recently developed in our laboratory.