Theoretical and experimental design for promoting the oxygen reduction activity of SrCoO3 perovskite-based cathode for PCFCs by bimetal-ions doping

Abstract

Low temperatures ceramic fuel cells (LT-CFCs) including solid oxide and proton conducting fuel cells (SOFCs/PCFCs), hold a great promise for abundant large-and small scaled real-application. Sluggish oxygen reduction reaction (ORR) activity at lower operating temperatures hindered the development of LT-CFCs. Strontium cobalt-based perovskite-oxides (SrCoO3−δ) materials have been frequently considered as a promising next-generation cathode for CFCs. Different doping stratigy are used to improve the mixed ionic (H+/O2-) and electronic conductivity of SrCoO3−δ, which help to extend the electrochemical reaction zone for oxygen reduction. Herein, we introduced bi-metal doping of La and Ce at B-site of SrCoO3−δ to produce SrCo0.8Ce0.1La0.1O3-δ (SCCL) pervoskite structure for PCFCs cathode. The developed SLCC cathode exhibits ultra-low-area-specific polarization resistance of 0.11 Ω ∙ cm2 and large oxygen reduction reaction (ORR) response at intermediate operating temperatures. We have demonstrated power density of 510 mWcm−2 using SLCC cathode over proton conducting BaCe0.7Zr0.2Y0.1O3-δ electrolyte at 600 °C and even with possible operation at 450 °C. The ORR activity of SLCC perovskites is found to strongly rely on the two proposed descriptors, where La and Ce doping at Co-site-in SrCoO3−δ located in the auspicious zone for predicting the moderate value of vacancy formation energy and ions migration barrier. The obtained results can further help to develop more functional SrCoO3−δ-based electro-catalysts for LT-CFCs and other related applications.