High-temperature electrolysis of synthetic seawater using solid oxide electrolyzer cells

A Ni-YSZ/YSZ/LSCF-GDC solid oxide electrolyzer cell (SOEC) is used to investigate the effects of seawater electrolysis for hydrogen production through electrolyzing steam produced from simulated seawater bath. Steam electrolysis using an SOEC with its fuel electrode contaminated by sea salt is also investigated. Steam produced from seawater is found to be free of contaminants, which are present in the seawater. Similar electrochemical performance is observed from the polarization curves and impedance spectra when using steam produced from pure water and seawater. Their short-term degradation rates are similar, which are registered at 15% 1000 h(-1) for both cases. For the case of direct sea salt contamination in an SOEC's fuel electrode, both the uncontaminated and contaminated cells exhibit rather similar performance as observed from the polarization curves and impedance spectra. The difference in ASR values from the polarization curves and impedance spectra between the uncontaminated and contaminated cell are all within a 10% range. Rather similar short-term degradation rates of 15% 1000 h(-1) and 16% 1000 h(-1) are recorded for the uncontaminated and contaminated cells, respectively. Post-mortem analysis shows that the sea salt impregnated into the cell has been vaporized at a typical SOEC operating temperature of 800 degrees C over the period of operation. (C) 2016 Elsevier B.V. All rights reserved.