Rational Design of NiO-8YSZ Screen-Printing Slurry for High-Performance Large-Area Solid Oxide Cells

An efficient and stable NiO-8YSZ hydrogen electrode for solid oxide cells (SOCs) is vital in the context of increasing global intermittent renewable energy sources. Most fundamental studies of SOCs have been carried out using button cells with small active areas, whereas the screen-printing of NiO-8YSZ hydrogen electrodes required for large-area SOCs have been ignored. In this study, we provide an alternative method for designing a highly active and stable fuel electrode for SOCs application by improving the slurry dispersant effect. The dispersion states and stabilities of NiO-8YSZ screen-printing slurries were quantitatively analyzed using the instability index, relaxation time, and viscosity. Scanning electron microscopy images of the resultant films indicate that the microstructure can be improved by optimizing the dispersants within the ink. The electrochemical performance of the resulting SOCs with optimized hydrogen electrode microstructures was examined at a 5 × 5 cm2 scale (16 cm2 active area). Single cells delivered a peak power density of 0.57 W·cm–2 at 750 °C in fuel cell mode and had a high current density of −0.81 A·cm–2 at 1.30 V in electrolysis mode. These results highlight the potential for large-scale high-performance SOCs production by designing NiO-8YSZ electrode nanostructures via a proper dispersant with the stability of screen-printing paste.