Enhanced Oxygen Electrocatalysis in Heterostructured Ceria Electrolytes for Intermediate-Temperature Solid Oxide Fuel Cells.

ABSTRACT: Heterostructured composite ceria electrolytes have been shown to accelerate the oxygen reduction activity and provide a new approach to improve solid oxide fuel cell (SOFC) performance. In this study, barium carbonate was added to gadolinium-doped ceria, Gd_0.2Ce_0.8O_2-? (GDC) electrolyte to improve the electrochemical performance of intermediate-temperature SOFCs. The heterostructured electrolyte was formed by the addition of 5 wt % BaCO₃ to a GDC electrolyte, resulting in a reaction during sintering that formed well-dispersed BaCe_0.8Gd_0.2O_3-? (BCG) throughout the electrolyte. The resulting material was tested as an electrolyte using La_0.6Sr_0.4Co_0.2Fe_0.8O_3-? as a cathode, resulting in a dramatic reduction to the polarization resistance of more than half the value (600 and 700 °C, the resistance was reduced from 2.49 and 0.23 ? cm² to 1.21 and 0.12 ? cm²) obtained by using pure GDC as an electrolyte. Furthermore, full cell SOFC tests employing the heterostructured electrolyte conducted during overextended durations indicated that the BCG phase in the 5BCG-GDC electrolyte was stable in an air atmosphere with no observed reactions with residual CO₂. This approach of tailoring surface reactivity by tailoring the composition and structure of the electrolyte as opposed to electrode materials provides an alternative method to improve fuel cell performance.

SUBMITTER: Hong T 

PROVIDER: S-EPMC6644590 | biostudies-literature | 2018 Oct

REPOSITORIES: biostudies-literature