High temperature solid oxide cell with exceptional thermo-mechanical stability operated in few seconds

Abstract

Solid oxide fuel cell (SOFC) with high electrical efficiency, environmental friendliness, and fuel flexibility is considered promising energy sources. However, due to their low thermomechanical instability attributed to ceramics properties, SOFC has challenges such as slow start-up/shut-down and low thermal cycling stability. Most studies have used the anode-supported SOFC to overcome the limitation for high performance. Due to its thin electrolyte and porous structure of the anode substrate, it has relatively high thermal stress resistance. However, the thermal stress is still limited by the low mechanical strength. Therefore, to overcome the inherent thermal stress vulnerability of ceramics, it is necessary to design the SOFC with a deep understanding of thermal stress.

This study proposes the electrolyte-supported SOFC capable of operation within a few seconds. The electrolyte-supported SOFC was designed to control the intrinsic and extrinsic properties. The material with high mechanical strength and toughness was adapted as an electrolyte material, and the thickness of the cell was dramatically reduced. The direct flame system was applied for the heating within a few seconds. Despite the harsh condition, such as rapid heating rate and ununiform temperature distribution, the fabricated cell exhibits superior thermal stress resistance compared to the anode-supported SOFC. The performance of the SOFC was optimized by controlling the parameters of the flame, obtaining the peak power density of 200 mV/cm2. Furthermore, the possibility of operation in a second is also confirmed.