Multi-functional perovskite oxide Pr 0.6 Sr 0.4 Mn 0.2 Fe 0.7 Ni 0.1 O 3− δ as an efficient quasi-symmetric electrode for solid oxide fuel/electrolysis cells

Solid oxide cells (SOCs) have recently gained attention as an efficient energy conversion system for a smart-grid that can resolve the intermittency of renewable energy. In particular, a symmetric configuration of the electrode has been developed to minimize fabrication cost and relieve compatibility issues. In this work, PSMFN (Pr 0.6 Sr 0.4 Mn 0.2 Fe 0.7 Ni 0.1 O 3− δ ) was developed and evaluated as a quasi-symmetric electrode for a solid oxide cell (Q-SSOC). A solid oxide cell fashioned with PSMFN–GDC (Ce 0.9 Gd 0.1 O 2 ) exhibited an electrochemical performance of 0.702 W cm −2 for H 2 -SOFC and 1.02 A cm −2 at a voltage of 1.5 V for CO 2 -SOEC at 800 °C. The physiochemical and electrochemical properties of PSMFN were investigated to elaborate this notable electrochemical performance of PSMFN–GDC. X-ray diffraction (XRD), microscopic analyses, and X-ray absorption near edge structure (XANES) indicated the occurrence of an exsolution of Fe–Ni alloy nanoparticles (NPs) along with a phase transition from the perovskite to the Ruddlesden–Popper structure. In addition, X-ray photoelectron spectroscopy (XPS) was utilized to elucidate the change in surface oxygen vacancies of the reduced PSMFN form. Furthermore, electrical conductivities and area specific resistances under an air atmosphere were measured to investigate the activities of PSMFN towards oxygen electrode reactions. From these analyses, PSMFN can provide numerous active sites both for electrode reactions with oxygen as well as fuel, which make it a promising quasi-symmetric electrode for an SOC.