Nanoscaled Sm-doped CeO2 buffer layers for intermediate-temperature solid oxide fuel cells

Abstract

A dense and crack-free nanoscaled Sm-doped CeO2 (SDC) thin film as a buffer layer for intermediate-temperature solid oxide fuel cells has been successfully deposited onto the polycrystalline yttria-stabilized zirconia (YSZ) electrolyte by pulsed laser deposition (PLD). SEM and XRD results reveal that the dense and crack-free buffer layer effectively prevents the formation of the insulating layer between the Ba0.5Sr0.5Co0.8Fe0.2O3-delta (BSCF) cathode and the YSZ electrolyte. The fuel cell with the as-deposited buffer layer exhibits high peak power density (e.g.,2016 mW cm-2 at 700 degrees Celcius) and low resistance. In contrast, at 700 degrees Celcius the fuel cell with an optimized SDC layer prepared by spray deposition or the fuel cell without interlayer have lower peak power densities, 1132 mW cm-2 and 60 mW cm-2 respectively, and higher resistances. The significant enhancement in peak power densities with the adoption of the SDC buffer layer by PLD is likely due to the combination of three factors: the lack of solid-state reaction between BSCF and YSZ, the thinner thickness in comparison to the SDC layer by spray deposition, as well as the improvement of the charge-transfer process.