Ni–YSZ gradient anodes for anode-supported SOFCs

A novel multilayer Ni–YSZ anode structure, which had a gradient in particle size and Ni content, was introduced in this paper. This gradient anode was co-fabricated with electrolyte by a symmetrical uniaxial die-pressing method. The anode functional layer (AFL) was developed to several sub-layers. The influences of different composition and various thickness of the AFL were investigated. The thickness of anode effective electrochemical reaction zone was ascertained to about 40–50 μm. A unit cell with gradient in both particle size and Ni content demonstrated a maximum power density of 467.14 mW cm−2. EIS result demonstrated that the surface dissociation/diffusion step is easier than charge-transfer reaction, which indicated that the microstructure of the anode, especially anode functional layer, was well fabricated and the distribution of the two phases was homogeneous thus the interfacial resistance was dampened.