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In situ fabrication of high-performance Ni-GDC-nanocube core-shell anode for low-temperature solid-oxide fuel cells.

Yamamoto K, Qiu N, Ohara S - Sci Rep (2015)

Bottom Line: The cermet anode effectively generated a Ni metal framework even at 500 °C with the growth of the Ni spheres.Furthermore, the macro- and microstructure of the Ni-GDC-nanocube anode were preserved before and after the power-generation test at 700 °C.Especially, the reactive {001} facets were stabled even after generation test, which served to reduce the activation energy for fuel oxidation successfully.

View Article: PubMed Central - PubMed

Affiliation: Joining and Welding Research Institute, Osaka University, 11-1 Mihogaoka, Ibaraki, Osaka 567-0047, Japan.

ABSTRACT
A core-shell anode consisting of nickel-gadolinium-doped-ceria (Ni-GDC) nanocubes was directly fabricated by a chemical process in a solution containing a nickel source and GDC nanocubes covered with highly reactive {001} facets. The cermet anode effectively generated a Ni metal framework even at 500 °C with the growth of the Ni spheres. Anode fabrication at such a low temperature without any sintering could insert a finely nanostructured layer close to the interface between the electrolyte and the anode. The maximum power density of the attractive anode was 97 mW cm(-2), which is higher than that of a conventional NiO-GDC anode prepared by an aerosol process at 55 mW cm(-2) and 600 °C, followed by sintering at 1300 °C. Furthermore, the macro- and microstructure of the Ni-GDC-nanocube anode were preserved before and after the power-generation test at 700 °C. Especially, the reactive {001} facets were stabled even after generation test, which served to reduce the activation energy for fuel oxidation successfully.

No MeSH data available.


Cross-sectional microscope images of Ni–GDC-nanocube(Ni:GDC = 65:35) anode.(a) Back-scattering image (BSI) before power-generation test.(b) Secondary-electron image (SEI) after power-generation testoperated at 700 °C. (c) BSI afterpower-generation test operated at 700 °C. (d)EPMA-WDX mapping images of Ni–GDC-nanocube(Ni:GDC = 65:35) anode after power-generation testoperated at 700 °C.
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f3: Cross-sectional microscope images of Ni–GDC-nanocube(Ni:GDC = 65:35) anode.(a) Back-scattering image (BSI) before power-generation test.(b) Secondary-electron image (SEI) after power-generation testoperated at 700 °C. (c) BSI afterpower-generation test operated at 700 °C. (d)EPMA-WDX mapping images of Ni–GDC-nanocube(Ni:GDC = 65:35) anode after power-generation testoperated at 700 °C.

Mentions: Cross-sectional SEM images of the Ni–GDC-nanocube(Ni:GDC = 65:35) cermet anode before and after thepower-generation test at 700 °C are shown in Fig. 3. Before the test, the back-scattering image (BSI) shows that theNi–GDC-nanocube anode consisted of a composite structure of a metallicNi sphere covered with fine GDC-nanocube particles (Fig. 3a).Furthermore, it was confirmed that the macrostructure of theNi–GDC-nanocube cermet as an electrode, which was established before thepower-generation test, remained unchanged even after the test at700 °C (Fig. 3b,c). Meanwhile, theneedle-like structures on the surface of the metallic Ni sphere disappeared afterthe power-generation test. The surface morphology became very smooth (Figs 1a and 3c), which means that the insitu fabrication of the metallic Ni framework for electrical powercollection resulted from insubstantial crystal growth of the metallic Ni sphere atthe operating temperature. The cross-sectional mapping images in Fig.3d, obtained from electron-probe micro-analysis wavelength-dispersivespectroscopy (EPMA-WDX) of the Ni–GDC-nanocube anode after thepower-generation test, indicate that the Ni and Ce signals were clearly separatedand formed contrasting images. Furthermore, the core-shell like morphology did notchange even after operating at 600 °C for 24 h(Figure S3a and b). It seems that this high stability of novelanode is contributed to the large particle size of Ni spheres and GDC nanocubeparticles on the surface of Ni spheres. Especially, GDC nanocube particles inhibitthe crystal growth and migration of Ni spheres. These results also confirm the highstability of the anode macrostructure.


In situ fabrication of high-performance Ni-GDC-nanocube core-shell anode for low-temperature solid-oxide fuel cells.

Yamamoto K, Qiu N, Ohara S - Sci Rep (2015)

Cross-sectional microscope images of Ni–GDC-nanocube(Ni:GDC = 65:35) anode.(a) Back-scattering image (BSI) before power-generation test.(b) Secondary-electron image (SEI) after power-generation testoperated at 700 °C. (c) BSI afterpower-generation test operated at 700 °C. (d)EPMA-WDX mapping images of Ni–GDC-nanocube(Ni:GDC = 65:35) anode after power-generation testoperated at 700 °C.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4663492&req=5

f3: Cross-sectional microscope images of Ni–GDC-nanocube(Ni:GDC = 65:35) anode.(a) Back-scattering image (BSI) before power-generation test.(b) Secondary-electron image (SEI) after power-generation testoperated at 700 °C. (c) BSI afterpower-generation test operated at 700 °C. (d)EPMA-WDX mapping images of Ni–GDC-nanocube(Ni:GDC = 65:35) anode after power-generation testoperated at 700 °C.
Mentions: Cross-sectional SEM images of the Ni–GDC-nanocube(Ni:GDC = 65:35) cermet anode before and after thepower-generation test at 700 °C are shown in Fig. 3. Before the test, the back-scattering image (BSI) shows that theNi–GDC-nanocube anode consisted of a composite structure of a metallicNi sphere covered with fine GDC-nanocube particles (Fig. 3a).Furthermore, it was confirmed that the macrostructure of theNi–GDC-nanocube cermet as an electrode, which was established before thepower-generation test, remained unchanged even after the test at700 °C (Fig. 3b,c). Meanwhile, theneedle-like structures on the surface of the metallic Ni sphere disappeared afterthe power-generation test. The surface morphology became very smooth (Figs 1a and 3c), which means that the insitu fabrication of the metallic Ni framework for electrical powercollection resulted from insubstantial crystal growth of the metallic Ni sphere atthe operating temperature. The cross-sectional mapping images in Fig.3d, obtained from electron-probe micro-analysis wavelength-dispersivespectroscopy (EPMA-WDX) of the Ni–GDC-nanocube anode after thepower-generation test, indicate that the Ni and Ce signals were clearly separatedand formed contrasting images. Furthermore, the core-shell like morphology did notchange even after operating at 600 °C for 24 h(Figure S3a and b). It seems that this high stability of novelanode is contributed to the large particle size of Ni spheres and GDC nanocubeparticles on the surface of Ni spheres. Especially, GDC nanocube particles inhibitthe crystal growth and migration of Ni spheres. These results also confirm the highstability of the anode macrostructure.

Bottom Line: The cermet anode effectively generated a Ni metal framework even at 500 °C with the growth of the Ni spheres.Furthermore, the macro- and microstructure of the Ni-GDC-nanocube anode were preserved before and after the power-generation test at 700 °C.Especially, the reactive {001} facets were stabled even after generation test, which served to reduce the activation energy for fuel oxidation successfully.

View Article: PubMed Central - PubMed

Affiliation: Joining and Welding Research Institute, Osaka University, 11-1 Mihogaoka, Ibaraki, Osaka 567-0047, Japan.

ABSTRACT
A core-shell anode consisting of nickel-gadolinium-doped-ceria (Ni-GDC) nanocubes was directly fabricated by a chemical process in a solution containing a nickel source and GDC nanocubes covered with highly reactive {001} facets. The cermet anode effectively generated a Ni metal framework even at 500 °C with the growth of the Ni spheres. Anode fabrication at such a low temperature without any sintering could insert a finely nanostructured layer close to the interface between the electrolyte and the anode. The maximum power density of the attractive anode was 97 mW cm(-2), which is higher than that of a conventional NiO-GDC anode prepared by an aerosol process at 55 mW cm(-2) and 600 °C, followed by sintering at 1300 °C. Furthermore, the macro- and microstructure of the Ni-GDC-nanocube anode were preserved before and after the power-generation test at 700 °C. Especially, the reactive {001} facets were stabled even after generation test, which served to reduce the activation energy for fuel oxidation successfully.

No MeSH data available.