Abstract
The effect of A-site cation ordering on the cathode performance and chemical stability of A-site cation ordered LaBaCo2O5+δ and disordered La0.5Ba0.5CoO3−δ materials are reported. Symmetric half-cells with a proton-conducting BaZr0.9Y0.1O3−δ electrolyte were prepared by ceramic processing, and good chemical compatibility of the materials was demonstrated. Both A-site ordered LaBaCo2O5+δ and A-site disordered La0.5Ba0.5CoO3−δ yield excellent cathode performance with Area Specific Resistances as low as 7.4 and 11.5 Ω·cm2 at 400 °C and 0.16 and 0.32 Ω·cm2 at 600 °C in 3% humidified synthetic air respectively. The oxygen vacancy concentration, electrical conductivity, basicity of cations and crystal structure were evaluated to rationalize the electrochemical performance of the two materials. The combination of high-basicity elements and high electrical conductivity as well as sufficient oxygen vacancy concentration explains the excellent performance of both LaBaCo2O5+δ and La0.5Ba0.5CoO3−δ materials at high temperatures. At lower temperatures, oxygen-deficiency in both materials is greatly reduced, leading to decreased performance despite the high basicity and electrical conductivity. A-site cation ordering leads to a higher oxygen vacancy concentration, which explains the better performance of LaBaCo2O5+δ. Finally, the more pronounced oxygen deficiency of the cation ordered polymorph and the lower chemical stability at reducing conditions were confirmed by coulometric titration.
Highlights
Proton ceramic fuel cells (PCFC) can potentially overcome some of the challenges currently limiting the commercial application of conventional solid oxide fuel cells (SOFCs) [1,2,3,4]
Several authors have studied the effects of A-site cation ordering on the performance of LaBaCo2 O5+δ and La0.5 Ba0.5 CoO3−δ for SOFC application [26,27,28], it has yet to be studied for PCFC application
Area Specific Resistances (ASR) as both A-site cation ordered and disordered materials lead to the same performance in moist conditions at at low low pO
Summary
Proton ceramic fuel cells (PCFC) can potentially overcome some of the challenges currently limiting the commercial application of conventional solid oxide fuel cells (SOFCs) [1,2,3,4]. Several authors have studied the effects of A-site cation ordering on the performance of LaBaCo2 O5+δ and La0.5 Ba0.5 CoO3−δ for SOFC application [26,27,28], it has yet to be studied for PCFC application Both the ordered and disordered variants demonstrate low polarization resistances at temperatures as low as 600 ◦ C (
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.