Quantitative Study on the Correlation between Solid Oxide Fuel Cell Ni-YSZ Composite Anode Performance and Reduction Temperature Based on Three-Dimensional Reconstruction

Abstract

The effects of reduction temperature on the initial performances and short-time durability of nickel-yttria-stabilized zirconia composite solid oxide fuel cell anodes were investigated. The anode microstructures before and after 100 hours operation were quantitatively analyzed by three-dimensional reconstruction based on focused ion beam-scanning electron microscopy technique. The anode reduced at 500°C showed the worst initial performance and stability in operation which was attributed to the smallest specific nickel-yttria-stabilized-zirconia interface area and the very porous nickel formed in low temperature reduction. The anode reduced at 800°C showed the smallest polarization resistance which was attributed to the largest active three phase boundary density. The anode reduced at 1000°C showed the most stable performance with polarization resistance enhanced in operation, which was attributed to the largest specific nickel-yttria-stabilized-zirconia interface area and the dense nickel phase formed in high temperature reduction. It is found that the performance of anode is determined not only by the active three phase boundary density but also the interface bonding between nickel and yttria-stabilized-zirconia in composite anode. Nickel-yttria-stabilized-zirconia interfacial bonding can be enhanced with the increase of reduction temperature, which is able to inhibit the nickel sintering and improve the anode performance stability in long-time operation.