TOF-SIMS characterization of impurity enrichment and redistribution in solid oxide electrolysis cells during operation

Abstract

TOF-SIMS analyses of state-of-the-art high temperature solid oxide electrolysis cells before and after testing under different operating conditions were performed. The investigated cells consist of an yttria stabilized zirconia (YSZ) electrolyte, a La1-xSrxMnO3-δ composite anode and a Ni-YSZ cermet cathode. The surfaces and cross-sections of the cells were analyzed, and several elemental impurities like Si, Ca and Na were identified and spatially mapped and their enrichment and migration during operation is reported. With advancing operation time, the concentration of these elements, especially Na and Ca, increases. For Si, a concentration gradient is found from the gas inlet to the gas outlet. Additionally, a loss of Ni percolation in the active cathode is observed in the same area where the Si enrichment is found. Based on the obtained TOF-SIMS results, the influence of the operating conditions on degradation is discussed.

A Decade of Solid Oxide Electrolysis Improvements at DTU Energy

“…There are numerous reports in literature on the effect of impurities on performance and durability of SOFC (9-18) and some research work also report on the effect of impurities on SOEC (7,(19)(20)(21)(22)(23)(24). In this review of SOEC improvements, we discuss two examples of impurity related SOEC degradation encountered during single cell SOEC testing at DTU Energy.…”

Secondary ion mass spectrometry signatures for verifying declarations of fissile‐material production

“…The optical profilometry measurements confirm that the observed corrosion layer is tens of micrometers thick, but also dictates that the 18.5 keV Osputter rate for the corrosion layer is relatively low. Future efforts may result in employing methods for producing cross-sections for given corrosion layers [25,26], which have been demonstrated herein to be time prohibitive for direct analysis by SIMS depth profiling. A method of particular interest is to use the micromachining abilities of a focused ion beam (FIB)…”

Redox‐Reversible Iron Orthovanadate Cathode for Solid Oxide Steam Electrolyzer

“…However, the R p of the FeV 2 O 4 /Fe composite cathode is still lower than conventional Ni–YSZ and perhaps the limited catalytic activity and insufficient porosity can account for this phenomenon. The R p for Ni–YSZ is around 0.1–0.5 Ω cm 2 under reducing conditions, though the Ni–YSZ can be oxidized by steam more easily in reducing atmospheres …”

“…The direct steam electrolysis has been achieved with this composite cathode though the performance is still lower than those of reported researches concerning those traditional Ni–YSZ cathodes. The current densities have reached approximately 1.0–1.5 A cm −2 for solid oxide electrolyzers with thin‐membrane YSZ electrolytes and under 1.5 V at 800 ºC . The high performance is mainly attributed to the lower ionic resistance of thin YSZ electrolytes and the high activity of Ni–YSZ cathodes.…”