Synthesis and electrical characterization of BaZr_(0.9)Ho_(0.1)O_(3-δ) electrolyte ceramic for IT - SOFCs

摘要

A cost-effective modified combustion method using citric acid and glycine has recently been developed to synthesize high quality, and nanosized BaZr_(0.9)Ho_(0.1)O_3 ceramic powder. BaZr_(0.9)Ho_(0.1)O_(3-δ) ceramic powder was characterized by X-ray diffraction (XRD), high-resolution transmission electron microscopy (HRTEM) and field emission scanning electron microscopy (FESEM). XRD pattern of BaZr_(0.9)Ho_(0.1)O_(3-δ) ceramic sintered at 1600 °C has shown that pure phase of BaZr_(0.9)Ho_(0.1)O_(3-δ) with cubic Pm3m space group symmetry. The transmission electron microscopic investigation has shown that the particle size of the powder calcined at 1100 °C was in the range 30-80 nm. The FESEM image of sintered pellet at 1600 °C for 4 h reveals porous nature of BaZr_(0.9)Ho_(0.1)O_(3-δ) with 83.7 relative density. Impedance analysis reveal three type relaxations in the temperature range 250 °C to 500 °C as studied at different frequencies over 100 Hz to 1 MHz in air. The grain boundary conductivity of BaZr_(0.9)Ho_(0.1)O_(3-δ) ceramic is found lower then grain (bulk) conductivity due to core-space charge layer behavior in grain boundary.