Effect of internal and external constraints on sintering behavior of thin film electrolytes for solid oxide fuel cells (SOFCs)

The effect of internal and external constraints on the sintering behavior of yttria-stabilized zirconia (YSZ) thin film electrolytes is investigated for intermediate-temperature solid oxide fuel cells (SOFCs). The external constraints imposed by rigid substrates result in major process flaws, such as vertical and delamination cracks during film densification, in a chemical solution deposition (CSD) process. In this study, YSZ nanoparticles are incorporated into the precursor solution to impose internal constraints and control the shrinkage rate of the sol-gel matrix. Because the structural stability of the thin film is determined by the grain size distribution, it is critical to optimize the content and dispersion structure of the nanoparticles and the sintering temperature to obtain a gas-tight thin film electrolyte for SOFCs. A clustering model is proposed to obtain a comprehensive understanding of the sintering behavior of the YSZ thin-film electrolyte containing the nanoparticles in the CSD process.