Preparation and characterization of Ni-YSZ composite electrode for solid oxide fuel cells by different co-precipitation routes

Abstract

In this study, two synthetic routes were used to prepare NiO-YSZ nanocomposite particles. The first one is an improved co-precipitation route, in which NiO-YSZ nanocomposite particles were synthesized by adding a nickel/yttrium nitrate solution to an organic base solution containing an anionic zirconium carbonate complex. The second one is the conventional co-precipitation method. The homogeneity and sinteractivity of the synthesized NiO/YSZ composite particles, as well as the subsequent microstructure and electrochemical performance of the resultant Ni-YSZ anode for the two synthetic routes were evaluated and compared in detail. The results show that the particles synthesized by the conventional co-precipitation route involved aggregated composites with a non-uniform distribution of NiO and YSZ phases. The particles showed poor sinteractivity, a coarse and inhomogeneous anode microstructure, and a moderate area-specific resistance (ASR) of 0.35 Ω cm2 at 800 °C under open circuit voltage (OCV). In contrast, homogeneous nanocomposite particles were successfully synthesized by the improved co-precipitation route. The particles showed better sinteractivity, a fine and uniform porous microstructure with a grain size in the range of 200–400 nm even at the sintering temperature of 1300 °C, and a low ASR of 0.16 Ω cm2 at 800 °C under OCV.