Effect of titania concentration on the grain boundary conductivity of Ce_(0.8)Gd_(0.2)O_(1.9) electrolyte

摘要

The effect of titania (TiO_2) addition on the densification, crystal structure and electrical property of Ce_(0.8)Gd_(0.2)O_(1.9) (GDC) are examined. TiO_2 addition reduces GDC sintering temperature by ～200 ℃ and considerably improves grain boundary conduction. The minimum grain boundary resistivity is obtained at 0.8 mol% TiO_2 concentration. XRD analysis suggests that the solubility limit of TiO_2 in GDC is ～0.6 mol%. The optimum doping level (0.8 mol%) is slightly higher than the solubility limit (0.6 mol%), which implies that a small amounts of TiO_2 (～0.2 mol%) at the grain boundaries benefits the grain-boundary conduction.