Analysis of Metallic Interconnects Using Secondary Ion Mass Spectrometry, Focused Ion Beam Microscopy, Raman Spectroscopy and Electrochemical Impedance Spectroscopy

摘要

The interconnect of solid oxide fuel cells (SOFCs) performs the vital role of separating fuel from air, conducting the electrical current between each layer of the stack, distributing reactant gas evenly across the face of each electrode and providing mechanical support to the stack. Metallic interconnects are more robust than ceramics and can withstand rapid temperature change associated with fast start-up; they also make it easier to incorporate internal structure into the stack such as internal manifolding, flow-field geometries or sealing wells. Operation in the 'intermediate' temperature (IT) regime (～500-800oC) allows relatively low cost stainless steel alloys to be used that deliver high performance. These steels owe their corrosion resistance to the formation of surface species, such as chromia, at the surface. Understanding the surface chemistry of these alloys when subjected to practical operating conditions is key to informing new alloy formulations and improving fuel cell performance.^