Innovative improvement of sintered ceramic electrolytes by salt infiltration

authors	Grilo, JPF; Macedo, DA; Nascimento, RM; Marques, FMB
nationality	International
journal	CERAMICS INTERNATIONAL
author keywords	Gd-doped ceria; Molten carbonates; Grain boundary; Impedance spectroscopy
keywords	GRAIN-BOUNDARY CONDUCTIVITY; DOPED CERIA; ELECTRICAL-CONDUCTIVITY; SOLID ELECTROLYTES; LITHIUM-OXIDE; SPACE-CHARGE; BEHAVIOR; CARBONATES; STABILITY; AID
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.
publisher	ELSEVIER SCI LTD
issn	0272-8842
isbn	1873-3956
year published	2021
volume	47
issue	4
beginning page	5079
ending page	5090
digital object identifier (doi)	10.1016/j.ceramint.2020.10.086
web of science category	12
subject category	Materials Science, Ceramics
unique article identifier	WOS:000608688100004