Anodic performance of bilayer Ni-YSZ SOFC anodes formed by electrophoretic deposition

Abstract

Bilayer Ni-YSZ anode films for SOFCs were prepared by electrophoretic deposition (EPD). The thickness of each layer of the bilayer anode films, which consist of 50 wt %Ni-YSZ as the active layer and 70 wt %Ni-YSZ as the current collecting layer (50Ni-YSZ/70Ni-YSZ), were controlled by the deposition time of the EPD process. For the monolayer anodes, 70Ni-YSZ showed a better performance than 50Ni-YSZ. The bilayer film, 50Ni-YSZ/70Ni-YSZ, showed an even better performance than the 70Ni-YSZ monolayer film. Probably, 50Ni-YSZ anode has more reaction sites compared to 70Ni-YSZ; on the other hand, 70Ni-YSZ has higher porosity to be a gas diffusion (or current collecting) layer. The anodic performance of the bilayer film significantly depended on the film thickness of the 50Ni-YSZ layer, and 3 µm was found to be the optimized thickness as the active layer, which suggests that the charge transfer reaction site extended up to a 3-µm thickness from the anode/electrolyte interface.