Thermal shock resistant solid oxide fuel cell ceramic composite electrolytes

Abstract

Next-generation solid oxide fuel cells (SOFCs) require rapid start up times to fit the requirements for automotive and aviation industries. However, rapidly started SOFCs suffer from degradation and failure of the fuel cell components. This is due to the difference in the thermal expansion coefficients (CTE) between the different components of the fuel cell, and especially the low thermal shock resistance (TSR) of the ceramic electrolyte. Introducing multi-phase materials to SOFC components can help manage the difference in CTE and improve the thermal shock resistance where it is lacking. In this research, we aim to change the electrolyte’s CTE. This is made possible by incorporating secondary phases, with a negative thermal expansion (NTE) coefficient. These can be formed during the sintering process by adding tungsten oxide to the powder. The produced composite electrolytes showed reduced effective CTE in the operating temperatures and an increase in the thermal shock resistance. Introduction of varied amounts of such a secondary phase, could allow tailoring of the CTE and therefore improving the durability of the SOFC in rapid start up times.