Suitability of Pr 2–x Ca x NiO 4+δ as cathode materials for electrochemical devices based on oxygen ion and proton conducting solid state electrolytes

Abstract In order to develop economically competitive solid oxide fuel cell (SOFC) systems it is necessary to design new functional materials with the purpose of enhancing their performance, extending operational lifetime and reducing the cost. The present work focuses on the study of Pr 2-x Ca x NiO 4+δ cathode materials prepared by a simple and cheap conventional solid state reaction method. The structure, oxygen nonstoichiometry, electrical properties and chemical compatibility of the materials with a number of well-known oxygen ion and proton conducting electrolytes were systematically investigated. Chemical composition (Ca content) and technological factors (powders pre-history, electrodes' sintering temperature), as well as external parameters (temperature, air humidity) were correlated with the electrochemical performance of the electrodes to determine the optimal compositions and conditions. Based on this study and testing results of the single anode-supported cell with BaCe 0.89 Gd 0.1 Cu 0.01 O 3-δ electrolyte, the Pr 1.7 Ca 0.3 NiO 4+δ -based electrode compositions are proposed for preferred usage in SOFCs in place of Pr 2 NiO 4+δ electrode.