The microstructural and thermal characteristics of NiO-samarium-doped ceria carbonate (NiO-DCC) composite powders have been explored in terms of NiO loading and pre-calcination temperature. NiO-SDCC composite powders were intimately mixed via fast ball-milling using different NiO loadings (50-70 wt. %) and subjected to various pre-calcination temperatures (600-800°C). Subsequently, the pre-calcined powders were then used to fabricate composite pellets using a uniaxial press and sintered at a low temperature of 600°C. The crystalline phase, carbonate bonding, microstructure and thermal behaviour of the composite anode powders were investigated. The microstructure, porosity, and hardness of sintered composite pellets were also evaluated. All samples maintained their chemical compatibility and carbonate bonding after various processes. The findings indicated that the pre-calcination factor was more important than NiO loading in terms of powder and pellet morphologies as well as the thermal expansion behaviour. Moreover, the composite pellets prepared with composite powders pre-calcined at increasing temperatures exhibited an increase in porosity, but within an acceptable range (30-40 %). Overall, composite pellets fabricated with 50 wt. % NiO exhibited the optimum hardness values of 21-31 HV and the lowest thermal expansion of 12.2-12.7 × 10-6 K-1 .
Addition of silver (Ag) as an electro-catalyst has been widely investigated to enhance the cathode performance for intermediate-to-low temperature solid oxide fuel cells. Ag is seldom incorporated into composite anode materials, especially for low temperature application. Therefore, this study aimed to investigate the effects of a small amount of Ag on the microstructure and thermal behaviour of nickel oxidesamarium-doped ceria carbonate (NiOSDCC) composite pellets. A high-speed ball milling technique was employed to prepare the NiOSDCC composite anode powder. Subsequently, a small amount of Ag (1, 3, and 5 wt.%) was added into NiOSDCC composite powder via ball milling. The pellets were manually pressed and sintered at 600 °C. Characterisation of the composite anodes included X-ray diffraction, Fourier transform infrared spectroscopy (FTIR), energy-dispersive spectroscopy, scanning electron microscopy, dilatometry and porosity measurement. NiOSDCC maintained good chemical compatibility regardless of Ag loading. FTIR analysis also verified the presence of carbonates, suggesting that Ag did not influence the carbonate bonding in all NiOSDCC. The porosity of all composite anodes was maintained within the satisfactory level for good anode performance (20%40%). The thermal expansion of the composite samples matched well with the SDCC electrolyte. This finding indicated that the addition of small Ag loading into NiOSDCC was within the acceptable range, demonstrating promising potential as low-temperature solid oxide fuel cell composite anode.
The characteristics of the starting powder in powder preparation method are important for enhancement of cell performance. In this study, the composite anode powders of NiO–samarium-doped ceria carbonates (SDCC) were prepared by using different NiO loadings (50–70 wt.%) via high-energy ball milling. The composite anode powders were ball-milled in ethanol at a milling speed of 550 rpm. The obtained NiO–SDCC composite anode powders were characterized by XRD, FTIR, FESEM, and EDS. Results indicate that the composite anode powders demonstrated good chemical compatibility between NiO and SDCC, given that no new phases were detected in the XRD analysis. FTIR spectra confirmed that the composite anode powders contain carbonates in amorphous state after high-energy ball milling. FESEM investigation revealed well-distributed fine particles and significant reduction of particle size at nanoscale compared with the powder prepared using NiO particles as the starting material. EDS mapping verified the homogeneity of the composite powder with good elemental distribution. Thus, high-energy ball milling is an effective method to prepare NiO–SDCC composite anode powders within a relatively short processing time.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.