Heavily neodymium doped ceria as an effective barrier layer in solid oxide electrochemical cells

Abstract

10 mol% gadolinium doped ceria (GDC10) is widely used as a barrier layer between oxygen electrode and electrolyte to prevent interfacial reactions. A 50 mol% neodymium doped ceria (NDC50) barrier layer has been proposed and studied in this paper. Symmetrical cells with NDC50 and GDC10 barrier layers, Nd2NiO4+δ(NNO)–Ce0.5Nd0.5O2-δ(NDC50) electrode, and YSZ electrolyte have been systematically studied using impedance spectroscopy (EIS) at various temperatures and oxygen partial pressure (pO2). The NDC50 barrier layer has significantly decreased polarization resistance across a wide temperature and pO2 range compared to the GDC10 barrier layer. The rare earth C-type structure of the NDC50 barrier layer causes barrier free migration of oxygen ions resulting in improved ionic conductivity compared to GDC10. Distribution of relaxation time (DRT) modeling has been used to obtain insights into the electrode processes.