Durability of SOFCs using inexpensive Ca-doped ZrO₂ electrolytes

For the further commercialization of SOFCs, the cost reduction for materials is one of the most important technological issues. Currently, Y or Sc is widely used as a dopant of zirconia-based electrolytes, but these rare-earth elements are relatively expensive. In this study, we have examined the possibility to use Ca as an alternative dopant since it is abundant in the earth and inexpensive. We have experimentally found that Ca diffusion is relatively fast, causing cell performance degradation. Even so, such fast diffusion could be depressed by decreasing the concentration gradient of Ca dopant, leading to an improvement in the durability.