Electrochemical characterization of PrBa2−xSrxCu3O6+δ layered oxides as innovative and efficient oxygen electrode for IT-SOFCs

Abstract

PrBa 2 Cu 3 O 6+δ (P) and PrBa 1.5 Sr 0.5 Cu 3 O 6+δ (PS) layered perovskite-type oxides are synthesized and characterized as oxygen electrodes in IT-SOFCs. The layered structure of P and PS compounds is constituted by the regular alternation along the crystallographic c axis of Pr O planes, Cu 2+ chains (CN = 4) and Cu 3+ pyramidal (CN = 5) layers. Interesting features of the PrBa 2 Cu 3 O 6+δ structure are the absence of cobalt, the presence of aliovalent cations and large amounts of oxygen vacancies. The substitution of 25% Ba with Sr is evaluated in order to improve the electronic conductivity of the undoped material. The compounds are synthesized via Citrate-Nitrate procedure and characterized by XRPD, 4-probe conductivity tests (100-800°C) and EIS measurements on symmetric cells in air varying the temperature (450-850°C). SEM images of post mortem cells are collected to evaluate the adhesion between components, layers thickness and particle morphology. Sr doping does not significantly improve the electrical conductivity but prompts a considerable hysteresis in the P sample between the cooling and the heating ramps. Conductivity values are lower than 100 S cm − 1 , but no electrical limitations are observed in EIS results. The introduction of a thin PrDC interlayer greatly reduces the Area Specific Resistances for both the compounds and the 0.15 Ω cm 2 target is almost fulfilled at 600°C (0.17 Ω cm 2 for PS + PrDC sample).

Synthesis and Characterization of High Temperature Properties of YBa2Cu3O6+δ Superconductor as Potential Cathode for Intermediate Temperature Solid Oxide Fuel Cells

“…x Sr x Cu 3 O 6+δ as an IT-SOFC cathode [17]. In this work, YBa 2 Cu 3 O 6+δ (YBC) powders were obtained through an auto-combustion reaction path and were characterized by X-ray diffraction (XRD) between room temperature (RT) and 700 °C to confirm phase formation and transformations and determine thermomechanical and chemical compatibility with Ce 0.9 Gd 0.1 O 1.95 (GDC) electrolyte material.…”