Léonard Kröll


„ Modeling of degradation phenomena in a SOFC anode “

Grain size evolution of nickel particles in a SOFC anode over 2000 hours. Left: measured  (Source: San Ping Jiang, Journal of Materials Science, 2003, 38, 3775-3782), right: modeled Copyright: Source: San Ping Jiang, Journal of Materials Science, 2003, 38, 3775-3782

The Solid-Oxide Fuel-Cell (SOFC) is a high-efficient and low-emission electricity generator, which can be fed with both hydrogen and fossil fuels. Due to its high operating temperature, it is envisaged for decentralized and stationary applications. Therefore, it has to able to run stable for at least 40,000 h, which means, that the degradation rate has to be minimized. In a SOFC many different degradation processes have already been identified and in several cases their basic mechanisms are understood. Nevertheless, a life-time prediction model has still not been developed.

In my thesis, I focus on the modeling of the anode degradation, especially on the effects, which base on the sintering of nickel particles, e.g. the increase in the resistivity and the change of the active catalytic area for the oxidation reaction of the fuel with the oxygen. Moreover, the effects of the operating parameters like the humidity and the flow rate are investigated in order to determine the long-term behavior of a SOFC.