Document Type

Article

Publication Date

4-1-2022

Abstract

A theoretical analysis on crack formation and propagation was performed based on the coupling between the electrochemical process, classical elasticity, and fracture mechanics. The chemical potential of oxygen, thus oxygen partial pressure, at the oxygen electrode-electrolyte interface (μO2OE/El ) was investigated as a function of transport properties, electrolyte thickness and operating conditions (e.g., steam concentration, constant current, and constant voltage). Our analysis shows that: a lower ionic area specific resistance (ASR), riOE, and a higher electronic ASR (reOE) of the oxygen electrode/electrolyte interface are in favor of suppressing crack formation. The μO2OE/El thus local pO2, are sensitive towards the operating parameters under galvanostatic or potentiostatic electrolysis. Constant current density electrolysis provides better robustness, especially at a high current density with a high steam content. While constant voltage electrolysis leads to greater variations of μO2OE/El Constant current electrolysis, however, is not suitable for an unstable oxygen electrode because μO2OE/El can reach a very high value with a gradually increased riOE A crack may only occur under certain conditions when pO2TPB > pcr .

Publication Source (Journal or Book title)

Journal of the Electrochemical Society

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