The impedance analysis for the aging mechanism of CaO excess type calcium zirconate electrolyte material comparing with 8.5 YSZ

• Confirmed the aging behavior in CaO excess calcium zirconate perovskite ceramics
• The aging behavior works more seriously as temperature rises.
• The Ca1.1Zr0.9O2.9 presents a much more stable conductivity than the 8.5 YSZ shows.
• The annealing operation enforces the formation of association [CaZr″ − VO
•
• ] and makes oxygen vacancy trapped.
• The lock of oxygen vacancy reduces its effective diffusion coefficient.

A CaO excess type calcium zirconate electrolyte with a composition of Ca1.1Zr0.9O2.9 was prepared. Its aging behavior at 900 °C and 1100 °C was evaluated by AC impedance. The conductivity decreases more seriously at higher temperature. Combined with the aging effect of 8.5 YSZ, the formation of [CaZr″ − VO
•
• ] promoted by annealing operation should be responsible for the aging effect in Ca1.1Zr0.9O2.9. The declined mobility of VO
•
• is viewed as the increase in hopping activation energy and the decrease in effective concentration of VO
•
• . Consequently, the diffusion coefficient of VO
•
• decreases and results in the aging behavior.