Enhanced Cr tolerance of perovskite oxide via Gd0.1Ce0.9O2 surface modifications

Abstract

Cr poisoning of the SUS interconnect and the solid oxide fuel cell electrode is one of the crucial hurdles to achieving system sustainability. Among various approaches to solving this issue, the suppression of cation segregation, especially Sr, and preventing the electrode surface from direct exposure to Cr-gas have been considered the most important factors. Herein, the effect of surface coating on mitigating Sr segregation as well as the use of strategies for protecting the electrode surface from exposure to Cr gas are discussed. Using Sm0.5Sr0.5CoO3(SSC) as a model film electrode and Gd0.1Ce0.9O2 (GDC) as the coating layer via a pulsed laser deposition (PLD) method, the Cr tolerance of the perovskite oxide electrode was enhanced. Electrochemical measurement at 650 °C for 200 h showed ∼2.5 times higher stability of the GDC-coated SSC electrode than the bare SSC electrode. Using Auger electron spectroscopy (AES), the chemical states of the GDC-coated SSC electrode were characterized, revealing significantly reduced Sr and Cr intensity on the surface of the coated electrode when compared to the bare SSC electrode.