Abstract
Solid oxide electrolysis is recognized as an important pathway to efficient and sustainable hydrogen production from water. However, high operating temperature is a major limitation for this technology that increases the degradation rate, particularly at high steam to hydrogen intake concentrations. The degradation in cell performance is caused by thermal stresses and result in higher overvoltage. In this paper, a novel thin-electrolyte solid oxide cell (SOC) is tested for intermediate (750 °C) versus high (850 °C) temperature hydrogen production. The experimental testing and performance analysis of a thin-electrolyte-supported SOC operating at high steam to hydrogen ratio is reported. The cell is based on YSZ-electrolyte with a thickness of about 150 μm and gadolinia-doped ceria (GDC) bi-layers. The study focuses on the impact of high steam to hydrogen ratios of up to 95% H2O to 5% H2 and compares it with that occurs at lower ratios. In this regard, performance indicators, such as the open circuit voltage (OCV) and the current density–voltage (J–V) curves are measured and compared with the theoretical values and relevant literature. Furthermore, the electrochemical impedance spectroscopy (EIS) is performed for the cell and the impact of high steam to hydrogen ratios operation on the cells' integrity and microstructure is also examined through the scanning electron microscope (SEM) and the energy-dispersive X-ray spectroscopy (EDS) techniques.
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•Thin-electrolyte solid oxide cell is tested for intermediate vs high temperature hydrogen production.•Cells tested at high steam to hydrogen ratios of up to 95% H2O to 5%H2.•Cells tested in both fuel cell and electrolysis cell modes.•Cell performance is analyzed considering thermal, electrochemical, and material performance.