Esther Jaekel

 

Boundaries of co-electrolysis

Product compositions for varied CO2-input fractions Copyright: L.Dittrich Product compositions for varied CO2-input fractions

For a compensation of the fluctuations of renewable energy production from e.g. wind and solar power, energy storage technologies have been developed and investigated. One possibility is to convert electrical energy to chemical energy carriers in electrolysis, according to the so-called power-to-X concept. This way for instance, water and carbon dioxide can be converted in co-electrolysis to syngas, a mixture of CO and H2. Syngas is a valuable raw material mixture which can be processed to synthetic fuel, methane, and other chemicals. The ideal composition of syngas depends on the further processing and can be customized via the chosen electrolysis parameters. However, the product mixture produced during co-electrolysis is in a complex thermodynamic equilibrium between H2 and CO2 on the one hand and H2O and CO on the other, according to the water gas shift (WGS) or reverse water gas shift (RWGS) reaction. It is therefore interesting to investigate the reaction of the system to a lack of water or carbon dioxide in the inlet gas. The investigation of the electrochemical processes of these boundaries with different operating parameters is the task of this work. Therefore, operating Ni-YSZ/YSZ/CGO /LSCF based SOCs are investigated via electrochemical methods (current-voltage characteristics, impedance spectroscopy).