abstract
Previously sintered (1500 degrees C, 4 h) dense pellets of Ce0.9Gd0.1O1.95 (GDC) were covered and heat treated with eutectic mixtures of Na2CO3 and Li2CO3 (NLC), and their electrical performance was assessed against pure GDC and chemically synthesized GDC + NLC. Microstructural analysis of NLC impregnated samples confirmed slight migration of the molten phase to the interior of the GDC pellets via grain boundaries, resulting in a significant improvement of the grain boundary conductivity, increasing with duration of heat treatment (0.5-2 h) and temperature (600-800 degrees C range). The observed total conductivity exceeded in almost 20% the corresponding values obtained for standard GDC samples. Cells tested before and after direct current polarization (0.5 V, 500 degrees C) showed the same electrical performance, discarding the possibility of parallel contributions of salt ions to the total conductivity. Grain boundary engineering using salt infiltration is an effective tool to improve the electrical performance of ceramic electrolytes.
keywords
GRAIN-BOUNDARY CONDUCTIVITY; DOPED CERIA; ELECTRICAL-CONDUCTIVITY; SOLID ELECTROLYTES; LITHIUM-OXIDE; SPACE-CHARGE; BEHAVIOR; CARBONATES; STABILITY; AID
subject category
Materials Science, Ceramics
authors
Grilo, JPF; Macedo, DA; Nascimento, RM; Marques, FMB
our authors
Fernando Manuel Bico Marques
Full professor
João Paulo de Freitas Grilo
Junior ResearcherProjects
acknowledgements
This work was funded by projects CO2ZERO (POCI-01-0145-FEDER016654-PTDC/CTM-CER/6732/2014), MOCO3-(M-ERA.NET2 2016 MOCO3-0009/2016), and CICECO-Aveiro Institute of Materials (FCT Ref. UID/CTM/50011/2019), financed by national (Portugal) funds through the FCT/MCTES, and when applicable co-financed by FEDER under the COMPETE 2020 Program. This work was also developed with funding from CNPq (Program Ciencia sem Fronteiras, Brazil).