Novel modification of anode microstructure for proton-conducting solid oxide fuel cells with BaZr0.8Y0.2O3−δ electrolytes

Proton-conducting BaZr0.8Y0.2O3−δ (BZY) electrolyte is hard to sinter and the good anode material has not yet been found. In this study, a BZY electrolyte layer is deposited using aerosol deposition (AD) method on top of a Ni-YSZ (yttria-stabilized zirconia) anode. A novel technique using phase transformation is developed for the modification of microstructure of Ni-YSZ. The Ni-YSZ of the anode functional layer (AFL) is transformed into Ni-BZY by heat treatment with atmospheric powder at temperature (1200 °C) substantially lower than the normal sintering temperature of cell fabrication. By the reaction of BaO vapor with YSZ particles in AFL, very fine BZY particles are homogeneously formed on large Ni particles and thus largely increase the triple-phase-boundaries (TPB). This results in a dramatic decrease of area-specific polarization resistance (0.21 Ω cm2 at 600 °C) and increase of peak power density (246 mW cm−2 at 600 °C) compared to those values (1.19 Ω cm2 and 84 mW cm−2) without the novel heat treatment. This is one of the best performances among the reported values of cells with BZY-based electrolyte.