Thin porous Ni–YSZ films as anodes for a solid oxide fuel cell

Porous Ni–YSZ (YSZ—yttria-stabilized zirconia) films were fabricated by reactive co-sputtering of a Ni and a Zr–Y target, followed by sequentially annealing in air at 900 °C and in vacuum at 800 °C. The Ni–YSZ films comprised small grains and pores that were tens of nanometers in size. The porous Ni–YSZ films were used as an anode on one side of a YSZ electrolyte disc and a La0.7Sr0.3MnO3 thick film was used as a cathode on the other side of the disc to form solid oxide fuel cells (SOFCs). The voltage–current curves of the SOFCs with single- and a triple-layered porous anodes were measured in a single-chamber configuration, in a mixture of CH4 and air (CH4:O2 volume ratio=2:1). The maximum power density of the SOFC using the single-layered porous Ni–YSZ thin films as the anode was 0.38 mW cm−2, which was lower than that of 0.76 mW cm−2, obtained using a screen-printed Ni–YSZ thick anode. The maximum power density of the SOFC with a thin anode was increased, but varied between 0.6 and 1.14 mW cm−2 when a triple-layered porous Ni–YSZ anode was used.