Manufacture of technical gas-diffusion electrodes
On the basis of commercially available silver powders with high purity and different shape or particle size, “technical” gas-diffusion electrodes (GDE) are produced for all project partners. With an established spraying process, electrodes of different thicknesses - self-supporting or on current collectors - can be manufactured. The wettability of the electrodes is influenced by varying the Ag / PTFE ratio in the suspension to be sprayed. These electrodes are required for the experimental work in the different subprojects. The porous GDE are physico-chemically characterized with various methods. This includes in particular the determination of the pore volume and the pore size distribution by means of physisorption, pycnometry, Hg porosimetry and porometry. As a result, volume-averaged detailed information on the pore system of the electrodes is available, which is supplemented by further ex-situ investigations. In addition, contact angle measurements provide information on the wettability with the electrolyte.