he high-energy rechargeable Li-O2 battery has been subject to intensive research worldwide during the past years. The Li-O2 cell mainly comprises a negative (e.g. Li metal) and positive (e.g. porous carbon) electrode separated by an electronically insulating, but Li+ conducting electrolyte layer. In order to study the cell chemistry, a differential electrochemical mass spectrometry setup based on a set of valves, a pressure sensor and a quadrupole mass spectrometer has been developed.
Components for the polymer electrolyte fuel cell (PEFC) are required to show high performance and durability under application relevant conditions. Furthermore, for commercial viability the materials and processes for component fabrication need to be of los cost. The polymer electrolyte membrane developed at PSI on the basis of the radiation grafting technique has the potential of being produced in cost-effective manner. In recent years, we have collaborated with the Belenos Clean Power to further develop the membrane to commercial competitiveness.
One way to utilize graphene and its’ outstanding specific surface area of 2630 m2g-1 for supercapacitor electrodes is by preparing a so called free-standing graphene paper. Such a flexible, conductive graphene-paper electrode was prepared by a flow-directed filtration of graphene oxide dispersion followed by a gentle thermal reduction treatment of the filtrate. The prepared partially reduced graphene oxide paper (GOPpr) showed a dense packing of graphene sheets with a distinct interlayer distance of 4.35 Å.
he optimization of thermochemical and electrochemical conversion systems is of high importance for a sustainable energy future society. Of particular interest regarding the performance of polymer electrolyte fuel cells (PEFCs) is the study of the gas flow in the gas diffusion layers (GDL). More specifically, permeability and diffusivity measurements in a model PEFC under normal operating conditions are highly desirable. As laboratory-measurements of these quantities under such conditions are very demanding, an alternative is the use of computer-based simulations.
Polymer electrolyte fuel cells (PEFC) convert the chemical energy of hydrogen with a high efficiency (40-70 %) directly into electricity. The product of the overall reaction is water, produced at the cathode of the cell.
The interaction of liquid water with the porous structures of the cell is one of the mechanisms in the PEFC that are commonly believed to be key for further optimization with regard to performance, durability and cost.
Major barriers for a successful commercialization of Polymer Electrolyte Fuel Cells (PEFCs) are insufficient lifetime and high cost of platinum catalyst. A comprehensive understanding of aging and transport phenomena on all relevant length scales is a key to improve durability and to reduce precious metal loading.
Flow fields as used in PEFCs for the distribution of the reactant gases over the electrode area cause inhomogeneities. The importance of down the channel inhomogeneities has been realized.