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Self-assembly formation of hollow Ni-Fe-O nanocage architectures by metal-organic frameworks with high-performance lithium storage.

Guo H, Li T, Chen W, Liu L, Qiao J, Zhang J - Sci Rep (2015)

Bottom Line: The stable cyclic performance is obtained for all rates from 1 C to 10 C.Even when the current reaches 10 C, the capacity can also arrive at 652 mAhg(-1).Subsequently, a specific capacity of ca. 975 mAhg(-1) is recovered when the current rate reduces back to 1 C after 200 cycles.

View Article: PubMed Central - PubMed

Affiliation: School of Chemistry Science and Engineering, Yunnan University, Kunming 650091,Yunnan, China.

ABSTRACT
A hollow hybrid Ni-Fe-O nanomaterial (NiFe2O4) is synthesized using a precursor of metal-organic frameworks through a simple and cost-effective method. The unique hollow nanocage structures shorten the length of Li-ion diffusion. The hollow structure offers a sufficient void space, which sufficiently alleviates the mechanical stress caused by volume change. Besides, the hybrid elements allow the volume change to take place in a stepwise manner during electrochemical cycle. And thus, the hierarchical hollow NiFe2O4 nanocage electrode exhibits extraordinary electrochemical performance. The stable cyclic performance is obtained for all rates from 1 C to 10 C. Even when the current reaches 10 C, the capacity can also arrive at 652 mAhg(-1). Subsequently, a specific capacity of ca. 975 mAhg(-1) is recovered when the current rate reduces back to 1 C after 200 cycles. This strategy that derived from NMOFs may shed light on a new route for large-scale synthesis of hollow porous hybrid nanocages for energy storage, environmental remediation and other novel applications.

No MeSH data available.


SEM (a) image and TEM (b) image of prepared Ni2[Fe(CN)6] nanocages (a) and hollow NiFe2O4 nanocages. SEM images (c), TEM (d) images, HRTEM micrographs (e) and selected area electron diffraction (SAED) (f) of as-synthesized hollow NiFe2O4 nanocages yielded by calcination at 350 °C.
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f4: SEM (a) image and TEM (b) image of prepared Ni2[Fe(CN)6] nanocages (a) and hollow NiFe2O4 nanocages. SEM images (c), TEM (d) images, HRTEM micrographs (e) and selected area electron diffraction (SAED) (f) of as-synthesized hollow NiFe2O4 nanocages yielded by calcination at 350 °C.

Mentions: Figure 4a,b show the SEM and TEM images of the Ni2Fe(CN)6 precursors. It is clear that the precursors are solid submicro-cubes with an average diameter of ca.100 nm according to Fig. 4a. A smooth surface can be seen on these solid submicro-cubes, as in Fig. 4b. The hollow porous morphology of NiFe2O4 nanocage sample is also characterized by SEM, TEM and HR-TEM, as illustrated in Fig. 4c–f. After calcination of Ni2Fe(CN)6 precursors at 350 °C for 4 hours, a fluffy black powder contains uniformly distributed nanocubes with a shrunk size as in Fig. 4c. It is interesting to find that the NiFe2O4 sample from NMOFs is not a solid box but a visible hollow porous interior structure with an average diameter of ca. 80 nm, as evidenced by the partial broken shell vividly, as shown in Fig. 4d. Particularly, a typical structure with well-defined interior and thin shell can also be detected. The size of as-obtained nanocages is much smaller than the previously reported porous nanostructures derived by NMOFs recently25. It is believed that the hollow porous structure of these particles might be induced by a rapid mass-transport from core to shell during the calcinations. The surface of the synthesized NiFe2O4 powder is made up from nano-sized small particles of ca. 3–9 nm, which is in a good agreement with XRD results. The selected-area electron diffraction (SAED) pattern (Fig. 4e,f) of one typical particle reveals the diffraction rings can be indexed to (2 2 0), (3 1 1), and (4 0 0) diffraction of face-centered cubic NiO, respectively. The lattice fringe with a lattice spacing (0.251 nm) can be seen clearly, agreeing with NiFe2O4 (3 1 1) plane spacing (Fig. 4f).


Self-assembly formation of hollow Ni-Fe-O nanocage architectures by metal-organic frameworks with high-performance lithium storage.

Guo H, Li T, Chen W, Liu L, Qiao J, Zhang J - Sci Rep (2015)

SEM (a) image and TEM (b) image of prepared Ni2[Fe(CN)6] nanocages (a) and hollow NiFe2O4 nanocages. SEM images (c), TEM (d) images, HRTEM micrographs (e) and selected area electron diffraction (SAED) (f) of as-synthesized hollow NiFe2O4 nanocages yielded by calcination at 350 °C.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4562299&req=5

f4: SEM (a) image and TEM (b) image of prepared Ni2[Fe(CN)6] nanocages (a) and hollow NiFe2O4 nanocages. SEM images (c), TEM (d) images, HRTEM micrographs (e) and selected area electron diffraction (SAED) (f) of as-synthesized hollow NiFe2O4 nanocages yielded by calcination at 350 °C.
Mentions: Figure 4a,b show the SEM and TEM images of the Ni2Fe(CN)6 precursors. It is clear that the precursors are solid submicro-cubes with an average diameter of ca.100 nm according to Fig. 4a. A smooth surface can be seen on these solid submicro-cubes, as in Fig. 4b. The hollow porous morphology of NiFe2O4 nanocage sample is also characterized by SEM, TEM and HR-TEM, as illustrated in Fig. 4c–f. After calcination of Ni2Fe(CN)6 precursors at 350 °C for 4 hours, a fluffy black powder contains uniformly distributed nanocubes with a shrunk size as in Fig. 4c. It is interesting to find that the NiFe2O4 sample from NMOFs is not a solid box but a visible hollow porous interior structure with an average diameter of ca. 80 nm, as evidenced by the partial broken shell vividly, as shown in Fig. 4d. Particularly, a typical structure with well-defined interior and thin shell can also be detected. The size of as-obtained nanocages is much smaller than the previously reported porous nanostructures derived by NMOFs recently25. It is believed that the hollow porous structure of these particles might be induced by a rapid mass-transport from core to shell during the calcinations. The surface of the synthesized NiFe2O4 powder is made up from nano-sized small particles of ca. 3–9 nm, which is in a good agreement with XRD results. The selected-area electron diffraction (SAED) pattern (Fig. 4e,f) of one typical particle reveals the diffraction rings can be indexed to (2 2 0), (3 1 1), and (4 0 0) diffraction of face-centered cubic NiO, respectively. The lattice fringe with a lattice spacing (0.251 nm) can be seen clearly, agreeing with NiFe2O4 (3 1 1) plane spacing (Fig. 4f).

Bottom Line: The stable cyclic performance is obtained for all rates from 1 C to 10 C.Even when the current reaches 10 C, the capacity can also arrive at 652 mAhg(-1).Subsequently, a specific capacity of ca. 975 mAhg(-1) is recovered when the current rate reduces back to 1 C after 200 cycles.

View Article: PubMed Central - PubMed

Affiliation: School of Chemistry Science and Engineering, Yunnan University, Kunming 650091,Yunnan, China.

ABSTRACT
A hollow hybrid Ni-Fe-O nanomaterial (NiFe2O4) is synthesized using a precursor of metal-organic frameworks through a simple and cost-effective method. The unique hollow nanocage structures shorten the length of Li-ion diffusion. The hollow structure offers a sufficient void space, which sufficiently alleviates the mechanical stress caused by volume change. Besides, the hybrid elements allow the volume change to take place in a stepwise manner during electrochemical cycle. And thus, the hierarchical hollow NiFe2O4 nanocage electrode exhibits extraordinary electrochemical performance. The stable cyclic performance is obtained for all rates from 1 C to 10 C. Even when the current reaches 10 C, the capacity can also arrive at 652 mAhg(-1). Subsequently, a specific capacity of ca. 975 mAhg(-1) is recovered when the current rate reduces back to 1 C after 200 cycles. This strategy that derived from NMOFs may shed light on a new route for large-scale synthesis of hollow porous hybrid nanocages for energy storage, environmental remediation and other novel applications.

No MeSH data available.