A detailed analysis of thermal and chemical compatibility of cathode materials suitable for BaCe0.8Y0.2O3−δ and BaZr0.8Y0.2O3−δ proton electrolytes for solid oxide fuel cell application

Abstract

The aim of this work is to identify suitable cathode materials for SOFCs based on proton-conducting electrolytes (SOFC-H+) in terms of long-term and thermal cycling stability along with a low polarization resistance. To this purpose a wide variety of materials, well known and new ones, are synthesized and their thermal and chemical compatibility is achieved by the aid of dilatometry study and XRD analysis of the calcined electrode/electrolyte mixtures, respectively.It is found that most of the studied cathodes exhibit significant thermal expansion along with striking chemical interaction with the electrolytes under investigation and despite of their intensive study presented in literature, their applications in H+-SOFCs is still questionable.On the base of experimental data, LaNi0.6Fe0.4O3−δ, La2NiO4+δ and Y0.8Ca0.2BaCo4O7+δ electrode materials have been selected for electrical and electrochemical characterization. It is found that bi-layer electrode with Y0.8Ca0.2BaCo4O7+δ functional layer and LaNi0.6Fe0.4O3 collector exhibits both the lowest polarization and serial resistances in contact with BaCe0.8Y0.2O3−δ electrolyte.