Complex Material Behavior Seen With Novel Internal Cathode Tubular Solid Oxide Fuel Cells

Abstract

Rapid climate change and the rising frequency of extreme natural weather events that it causes motivate a paradigm shift in how energy is produced, directing much research interest towards combined heat and power (CHP) systems. With the fuel flexibility offered by solid oxide fuel cells (SOFCs) and their need for high operation temperatures, combustion systems become obvious targets for integration. The fuel-rich combustion of natural gas can produce synthesis gas, while providing the heat necessary for SOFC operation. To remedy issues associated with degradation of cell components, tubular SOFCS (tSOFCs) are best suited to this application. To match the environment present within the combustion chamber, tSOFCs must be turned inside-out yielding novel geometry internal cathode-tSFOCs (IC-tSOFCs). IC-tSOFC development has revealed a wide variety of unexpected and yet fascinating material phenomenon. One example is the unique stress distribution present in these cells during sintering which ultimately leads to cracking. Another is the effect of the exothermic reaction of water formation at the anode which raises cell surface temperatures much higher than that of the environment, to the point of melting metal contacts. These behaviors, though cumbersome, motivate investigation into fundamental ceramic material behavior and ultimately adoption of new techniques to better control ceramic processing.