Effects of CoO and Bi2O3 single/dual sintering aids doping on structure and properties of Ce0.8Nd0.2O1.9

摘要

Nd0.2Ce0.8O3-delta (NDC) is one of the most common solid electrolyte materials used in solid oxide fuel cells (SOFCs). However, the densification temperature of NDC electrolyte is above 1400 degrees C. In this work, Bi2O3 and CoO sintering aids were individually or synergistically added to Nd0.2Ce0.8O3-delta(NDC) electrolytes through the sol-gel method to lower its sintering temperature. Effects of Bi2O3-CoO dual sintering aid on the sintering behavior, phase composition, microstructure, and electrochemical properties of NDC electrolyte were all investigated. The data revealed that Bi2O3-CoO dual-sintering aid doped-NDC (labeled as NDC-CB) possessed high density and superior conductivity at low temperatures, better than that of Bi2O3 or CoO single sintering aid. NDC electrolyte doped with Bi2O3-CoO dual-sintering aid achieved highest relative density of 95.3% at 1100 degrees C and total conductivity of 5.765 x 10(-2) S cm(-1) at 800 degrees C. Furthermore, NDC-CB displayed excellent physical and chemical compatibility with La0.68Sr0.4Co0.8Fe0.2O3-delta (LSCF) cathode and NiO-NDC anode. Oxygen reduction reaction at LSCF/NDC-CB interface was improved by about 40% when compared to NDC. In sum, Bi2O3-CoO looks promising as dual-sintering additive for lowing sintering temperature and increasing electrical conductivity of NDC. Therefore, NDC-CB might be potential electrolyte for future intermediate-temperature solid oxide fuel cells (IT-SOFCs).