Role of Operating Modes on the Performance Durability of Solid Oxide Cells: A Comparison between Potentiostatic and Galvanostatic Operations

Abstract

The commercialization of solid oxide cells for power generation or hydrogen production requires extended cell lifetime and durability. A solid oxide cell can operate either under a potentiostatic or a galvanostatic mode. It remains unclear what’s the role of those two operating modes on the performance durability of solid oxide cells, which limits our understanding and subsequently predicting service life and reliability of solid oxide cells.It is known that many degradation phenomena in solid oxide cells can be accelerated by the electrochemical operations, which manifest various distributions of oxygen chemical potential (μO2) across a solid oxide cell. The variation in the local μO2 is a central driving force for the phase transformation, demixing, and microstructure evolution, leading to a higher resistance of the cell components and decreasing cell performance. As a response to the degradation, the μO2 redistributes across the cell and the driving force for the degradation changes. The μO2 distribution differs when a cell operates at a constant current or a constant voltage. The driving force with different extents of degradation under both operation modes is compared to establish the optimum operation approach, which can shed light on identifying mitigation strategies to improve performance durability with existing cell configurations and materials. Acknowledgement We greatly appreciate the support from U.S. Department of Energy’s Office of Fossil Energy and Carbon Management under DE-FE0032110. Part of this work is supported by U.S. National Science Foundation under NSF-2119688.