Defect Chemistry Analysis of the Nonstoichiometry and Conductivity in Pr1-XNdxO2-D

Wednesday, 4 October 2017
Prince George's Exhibit Hall D/E (Gaylord National Resort and Convention Center)
Y. Wang, E. Dogdibegovic, B. Koser, and X. D. Zhou (University of South Carolina)
Pr1-xNdxO2-d is a potential compound to add into (Pr,Nd)2NiO4 (PNNO) to further improve the activity and phase stability of PNNO used as the cathode for solid oxide fuel cells. In this work, we employ defect chemistry to investigate the nonstoichiometry and electrical conductivity of Pr1-xNdxO2-d (0 <x < 1). The powders of Pr1-xNdxO2-d are synthesized from a glycine-nitrate combustion method, followed by high temperature calcination. The Pr1-xNdxO2-d bars are sintered at various temperatures to obtain a dense ceramic. Electronic and ionic conductivities are measured from 650 to 850 °C by using a blocking electrode based on Hebb-Wagner method. In Pr rich compounds, the electronic conductance dominates. This is consistent with the DFT calculation showing a higher density of states (DOS) at the Fermi level with a richer Pr; while the extracted DOS at the Fermi level sharply decreases in Nd-rich compounds.