Spinel and Perovskite Protection Layers Between Crofer22APU and La[sub 0.8]Sr[sub 0.2]FeO[sub 3] Cathode Materials for SOFC Interconnects

Abstract

The interaction of the metallic interconnects with the cathode and the resulting time-dependent resistance of these material combinations is a major problem in solid oxide fuel cells (SOFCs). In this study, different conductive oxide coatings were used as protective layers to improve surface stability and electrical performance, as well as to mitigate or prevent chromium poisoning of the cells. Dense layers were obtained on the steel by electron-beam physical vapor deposition, by screen printing and by electroplating. The degradation of the interface between the coated Crofer22APU alloy and the normalLa0.8normalSr0.2FenormalO3 (LSF) cathode was studied by resistance measurements in air at 800°C up to 1000h and analyzed by scanning electron microscopy, energy-dispersive X-ray analysis, X-ray diffraction, and secondary ion mass spectrometry after exposure. normalLa0.6normalSr0.4FenormalO3 measured the lowest resistance between the tested coatings. The highest resistance was found for CenormalO2 , which also showed low protection against SrCrnormalO4 formation. normalY2normalO3 exhibited the lowest resistance increase; however, this coating was not protective enough to prevent the formation of SrCrnormalO4 , especially during cyclic operation. Among the Mn–Co–Fe spinel compositions tested, the lowest resistivity values and the highest Cr retention were obtained with the MnnormalCo1.9normalFe0.1normalO4 spinel.

Fabrication of Mn1.5Co1.5O4 by Electrostatic Spray Deposition for Application as Protective Coating on Alloy Interconnects for Solid Oxide Fuel Cells

“…Indeed, platinum meshes were used as current collectors to avoid diffusion of platinum in the growing oxide scale. For longer aging times, the ASR increases steadily, as already observed for uncoated ferritic steels with similar chromium content (17,30). This ASR increase is likely to be related to the continuous growth of the oxide scale.…”

Coated stainless steel 441 as interconnect material for solid oxide fuel cells: Evolution of electrical properties

“…In cases where LSM or LSC is used one has also encountered sintering effects in the early stages of exposure, the contact area is undefined, and there is a higher electrode resistance and also contact resistance [15,25]. Additionally interactions between the electrodes with the interconnect steels have been reported [26].…”

Effect of Sr and Ca dopants on oxidation and electrical properties of lanthanum chromite-coated AISI 430 stainless steel for solid oxide fuel cell interconnect application

“…Different coating techniques have been used, including plasma spray coating [29,30], laser ablation [31], chemical vapor deposition (CVD) [32,33], screen printing [34,35], electron-beam physical vapor deposition (EB-PVD) [36], RF-magnetron sputtering [37] and wet chemical techniques, to create the protective ceramic film on the substrate [9,38,39]. Among the above mentioned techniques, sol-gel route submits important privileges, namely high resulting homogeneity, low sintering temperature and low cost [11,25,40].…”