Metal-oxide nanocomposite catalyst simultaneously boosts the oxygen reduction reactivity and chemical stability of solid oxide fuel cell cathode

Conductive perovskite oxides have received much attention as promising candidates for solid oxide fuel cell (SOFC) cathodes. However, they show chemical instability due to the segregation of A-site cations on the surface at high temperatures, which causes their performance to degrade. Moreover, the high activation barrier to ox-ygen reduction reactions makes these materials more difficult to use as electrodes at lower temperatures (less than 700 degrees C). Herein, by combining two general techniques: nanoparticle infiltration and atomic layer deposition (ALD), we significantly improve both the durability and reactivity of a state-of-the-art perovskite oxide, La0.6Sr0.4Co0.2Fe0.8O3-delta (LSCF). Ag nanocatalysts are dispersed onto an LSCF cathode via wet infiltration, after which they are covered with a thin ZrO2 layer via ALD to prevent the agglomeration of nanocatalysts and the segregation of Sr ions. Accordingly, the Ag/ZrO2 nanocomposite-deposited LSCF cathode shows the electrode resistance of 0.085 Omega cm2 at 650 degrees C over 200 h, which is, to the best of our knowledge, the near-record level among all nanocatalyst-infiltrated LSCF cathode to date. Our result suggests a new research direction to fully utilize nanocatalysts and perovskite oxides in SOFCs, which can be a shortcut to their commercialization.

Automated summary

Conductive perovskite oxides have potential as SOFC cathodes, but their chemical instability and high activation barrier limit their performance. In this study, by combining nanoparticle infiltration and ALD techniques, the durability and reactivity of a perovskite oxide (LSCF) were significantly improved. The Ag/ZrO2 nanocomposite-deposited LSCF cathode showed record-level electrode resistance, suggesting a new research direction for the commercialization of nanocatalysts and perovskite oxides in SOFCs.