A comprehensive comparison of performances of anode-supported, cathode-supported, and electrolyte-supported solid oxide fuel cells during warming-up process

Abstract

Although the influence of supporting layer features on the steady performance of solid oxide fuel cells (SOFCs) has been discussed in previous studies, the literature shows a lack of similar studies for unsteady performance. The present study numerically assesses the effects of the type and thickness of the supporting layer on the warming-up process of an SOFC. The warming-up process is desired to be rapid; however, the rapidness can impose harmful temperature gradients. The warming-up process is also energy-demanding. Therefore, all the mentioned factors are considered in the present study, and an optimal set of supporting layer features is proposed using a multi-criteria decision analysis approach. The results indicate that the warming-up durations of anode-supported and cathode-supported cells are close to each other but considerably lower than that of the electrolyte-supported cell. Furthermore, the warming-up duration, which is directly proportional to the supporting layer thickness, is more sensitive to the electrolyte thickness than the anode and cathode thicknesses. On the other hand, the temperature gradients inside the SOFC, which are inversely proportional to the supporting layer thickness, are more affected by the electrolyte thickness than the anode and cathode thicknesses. In terms of energy usage, the electrode-supported cells are seen to be superior to the electrolyte-supported cells. Considering all the concerns simultaneously, the anode-supported cell with a supporting layer thickness of 1.5 mm is proposed as the best trade-off solution.