Thin film yttria-stabilized zirconia (YSZ) electrolyte fabricated by a novel chemical solution deposition (CSD) process for solid oxide fuel cells (SOFCs)

Thin film yttria-stabilized zirconia (YSZ) electrolyte was fabricated on a rigid anode substrate by multiple spin coating of a chemical solution and low-temperature sintering. Differential densification resulted in reduced densification and microstructural heterogeneity due to the global constraint of the rigid substrate. Microstructural heterogeneity and pore anisotropy were greatly diminished by incorporating YSZ nanoparticles into the chemical solution; these act as local constraints in the precursor powder matrix. The resulting YSZ electrolyte had a residual porosity of 10-15% in the closed state, a thickness of about 500-700 nm, and grain/pore sizes less than 100 nm. A thin-film electrolyte cell showed a stable open-circuit voltage value of about 1.07 V with fairly good gas tightness, and exhibited a maximum power density of 427 mW/cm ² at 600 °C, demonstrating that YSZ is a potential alternative to vacuum deposition techniques.