Journal
ADVANCED ENERGY MATERIALS
Volume 9, Issue 38, Pages -Publisher
WILEY-V C H VERLAG GMBH
DOI: 10.1002/aenm.201902384
Keywords
BaCo0; 4Fe0; 4Zr0; 1Y0; 1O(3-)(delta); cation deficiency; oxygen reduction reaction; solid oxide fuel cells
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Funding
- National Science Foundation of China [21706129, 21878158, 21828801, 21576135]
- China Postdoctoral Science Foundation [2018M642236]
- Jiangsu Natural Science Foundation for Distinguished Young Scholars [BK20170043]
- Jiangsu Postdoctoral Science Foundation
- Program for Jiangsu Specially-Appointed Professors
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Doped perovskite oxides with the general formula of A(x)A ' 1-xByB ' O-1-(y)3 have been extensively exploited as the cathode materials of solid oxide fuel cells (SOFCs), but the performance at low-to-medium temperatures still needs improvement. BaCo0.4Fe0.4Zr0.1Y0.1O3-delta (BCFZY) has been recently reported to show promising oxygen reduction reaction (ORR) activity under SOFCs' operating conditions. Here, it is reported that the activity of BCFZY can be further boosted via introducing a slight B-site cation deficiency into the oxide lattice, and such an improvement is assigned to an increase in oxygen mobility that brings enhancement in both surface exchange and bulk diffusion kinetics. Specifically, materials with the nominal composition of Ba(Co0.4Fe0.4Zr0.1Y0.1)(0.975)O-3-(delta) and Ba(Co0.4Fe0.4Zr0.1Y0.1)(0.95)O-3-(delta) show significantly improved activity for ORR at reduced temperatures with the area specific resistances of 0.011 and 0.024 omega cm(2) at 600 degrees C, as a comparison of 0.042 omega cm(2) for the cation stoichiometric BCFZY. Excessive B-site deficiencies, however, lead to the formation of impurity phases, which cause a block for charge transfer and, consequently, a reduction in electrode performance. Introducing a B-site cation deficiency is a promising way to optimize the activity of perovskite oxides for ORR at reduced temperatures, but the degree of deficiency shall be carefully tuned.
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