Fabrication and Characterization of Metal-supported Solid Oxide Electrolysis Cells

Kurzfassung

Solid oxide electrolysis cells (SOECs) belong to the most efficient and cost-effective electrochemical devices for the energy storage application via power to gas (P2G) concept. Intermittent energy in form of electricity or heat from renewable sources can be stored long-termly in the magnitude of GWh level as chemical energy in H2 and CO through the electrolysis process occurs in SOEC systems. In comparison to conventional anode-supported and electrolyte-supported full ceramic cells, metal supported cells has many advantages, such as reduced manufacturing and maintenance cost, fast start-up features, excellent mechanical, thermal and redox cycle stability, and etc. In this work, novel metal-supported cells were fabricated on robust porous ferritic steel. Nickel free composite made of La0.1Sr0.9TiO3-α (LST) and gadolinium doped ceria (GDC) was applied as fuel electrode material. 3 m thick thin-film bilayer electrolyte of GDC/yttrium-stabilized zirconia (YSZ) was prepared by a combination of physical vapour deposition (PVD) and wet ceramic processing. The fuel electrode and La0.6Sr0.4Co0.2Fe0.8O3-δ (LSCF) air electrode were both deposited by screen printing. The gas-tightness of the electrolyte was monitored by differential air leakage tests at room temperature. Half cells with low leakage rate were selected and loaded with nickel nanoparticles as catalysts into the LST-GDC backbones to improve the electrochemical performance of the fuel electrode. Cells were tested under fuel cell mode and electrolysis mode, respectively. Performance and aging characteristics during operation were analysed by electrochemical impedance spectroscopy (EIS) and chronopotentiometry. Subsequently, the post mortem analysis was applied to facilitate the understanding of the degradation features and mechanisms specific to the electrolysis operation of the metal-supported cells.