Study On Surface Modification Of SOFC Metal Interconnect Using LaCo_0.6Ni_0.4O_3-? New Cathode Contact Materials

The new cathode contact material LaCo_0.6Ni_0.4O_3-??LCN?is commonly applied between the cathode of the SOFC and the metal connector to perform current collection.At the same time,it was found that LCN can play an important role in preventing oxidation of the metal connector.This article outlines the development history of solid oxide fuel cell interconnects,especially the excellent properties and broad application prospects of Fe-Cr ferrite alloys as interconnects.According to the current research status of metal connectors,the purpose and significance of this paper are put forward.Screen printing was used to coat different particle size LCN powder paste on the SUS 430 alloy surface.Since the working temperature of the solid oxide fuel cell is between 650°C and 800°C,the effect of the in-situ LCN coating on the oxidation kinetics and electrical conductivity of the joint alloy can be studied,especially the role of the coating thickness in the solid oxide fuel cell.It was found that the LCN slurry with a particle size of 200 nm was coated on the surface of SUS 430 alloy,which could effectively improve the oxidation resistance of the alloy.The thickness of the oxide layer after the coating alloy was oxidized for 500 h was only 0.3?m at the 750°C“four-point method”,The measured surface specific resistance?ASR?of the coated alloy after oxidation was 54 m?·cm²;The LaCo_0.6Ni_0.4O₃ slurry with a particle size of 800 nm was coated on the surface of the SUS 430 alloy.The thickness of the oxide layer after the coating alloy was oxidized for 500 h was about 0.5?m,and the ASR measured was 64 m?·cm².The antioxidant capacity of the two experimental groups was significantly better than that of the linker alloy,indicating that the LCN powder can effectively improve the oxidation resistance of the alloy,and the finer LCN powder shows better performance.Experimental studies of different LCN coating thicknesses show that as the coating thickness increases,the thickness of the oxide layer formed on the surface of the alloy gradually decreases,and the ASR decreases first and then increases.Considering the high temperature oxidation resistance and electrical conductivity of the metal connector,the optimal performance of the LCN coating thickness is 20?m.By regulation of the microstructure of the cathode interface layer,study the high-temperature oxidation kinetics of LCN-coated alloys,and alloy oxide film growth,phase composition,the impact element distribution and morphology and the like,the quantitative relationship between the oxidation and conductivity of the alloy was determined.On this basis,the mechanism of the in-situ protective layer of LCN to improve the high-temperature oxidation resistance of the joint alloy is elucidated,which provides a theoretical basis for the application of the cathode in-situ coating to the solid oxide fuel cell metal connector.