Oxygen-reduction at gas-diffusion electrodes in aqueous electrolyte
DFG Research Unit „Multiscale analysis of complex three-phase systems" (FOR 2397)
Gas-diffusion electrodes (GDE) are key components for different electrochemical processes. This includes the transformation of chemically stored energy into electrical energy in fuel cells and metal-air batteries as well as the reversal of these energy conversion processes in the chlor-alkali electrolysis or CO2 electrolysis. However, in many technologies, GDE are the limiting components and thus the main cost factor.
To improve the efficiency of GDE, it is necessary to have an overall comprehension of the complex interaction of transport and reaction processes inside the electrodes. In order to investigate these processes, subprojects of seven research facilities in Germany are combined in the DFG Research Unit FOR 2397.
At ICVT, working GDE are produced from silver powders and characterized by different methods. The measurements involve physico-chemical characterization of the pore systems and electrochemical measurements in half-cells. Based on these measurements it is possible to determine quantatively the effect of process conditions and electrode properties on the overpotential of the oxygen and CO2 reduction reactions. Results of all subprojects will be also used to develop a mathematical model, which describes the stationary overpotential of the GDE.