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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.


TEM images of porous NiFe2O4 nanocages obtained at (a) 150 °C, (b) 200 °C, (c) 250 °C, (d) 300 °C, (e) 350 °C, and (f) 400 °C for 4 h.
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f6: TEM images of porous NiFe2O4 nanocages obtained at (a) 150 °C, (b) 200 °C, (c) 250 °C, (d) 300 °C, (e) 350 °C, and (f) 400 °C for 4 h.

Mentions: The formation mechanism can be further investigated through a series of experiments as shown in Fig. 6, which presents the TEM images of NiFe2O4 obtained after calcination at 150 °C, 200 °C, 250 °C, 300 °C, 350 °C and 400 °C for 4 hours, respectively. It can be seen that only solid nanocages with a smooth surface can be formed after calcination at 150 °C (Fig. 6a). When the reaction temperature is increased to 200 °C, the sample surface becomes a little coarse and shows a porous structure (Fig. 6b). With continuously increasing the temperature up to 250 °C, the sample surface become even more coarser, and the hollow configuration is appearing gradually (Fig. 6c). It can be significantly noticed that the porous nanocage can be transformed into hollow one while the temperature is increased to 300 °C (Fig. 6d). With further increasing the temperature, the interior of the nanocage structure is broken and nanocage becomes a small nano particle with sizes of ca. 4–8 nm, as shown in Fig. 6e,f which are corresponding to those at 350 °C and 400 °C, respectively. According to these observations, it can be speculated that the formation of unique hollow porous NiFe2O4 nanocages go through the transformation from solid to hollow ones, which may be induced by the quick evolution of CO2 and NOx gases during the thermal decomposition process. It can be stated here that our strategy, as shown in Fig. 1, can provide a novel procedure and simple route to prepare hierarchical hollow porous nanocages from NMOFs with higher BET surface and larger quantity.


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)

TEM images of porous NiFe2O4 nanocages obtained at (a) 150 °C, (b) 200 °C, (c) 250 °C, (d) 300 °C, (e) 350 °C, and (f) 400 °C for 4 h.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

f6: TEM images of porous NiFe2O4 nanocages obtained at (a) 150 °C, (b) 200 °C, (c) 250 °C, (d) 300 °C, (e) 350 °C, and (f) 400 °C for 4 h.
Mentions: The formation mechanism can be further investigated through a series of experiments as shown in Fig. 6, which presents the TEM images of NiFe2O4 obtained after calcination at 150 °C, 200 °C, 250 °C, 300 °C, 350 °C and 400 °C for 4 hours, respectively. It can be seen that only solid nanocages with a smooth surface can be formed after calcination at 150 °C (Fig. 6a). When the reaction temperature is increased to 200 °C, the sample surface becomes a little coarse and shows a porous structure (Fig. 6b). With continuously increasing the temperature up to 250 °C, the sample surface become even more coarser, and the hollow configuration is appearing gradually (Fig. 6c). It can be significantly noticed that the porous nanocage can be transformed into hollow one while the temperature is increased to 300 °C (Fig. 6d). With further increasing the temperature, the interior of the nanocage structure is broken and nanocage becomes a small nano particle with sizes of ca. 4–8 nm, as shown in Fig. 6e,f which are corresponding to those at 350 °C and 400 °C, respectively. According to these observations, it can be speculated that the formation of unique hollow porous NiFe2O4 nanocages go through the transformation from solid to hollow ones, which may be induced by the quick evolution of CO2 and NOx gases during the thermal decomposition process. It can be stated here that our strategy, as shown in Fig. 1, can provide a novel procedure and simple route to prepare hierarchical hollow porous nanocages from NMOFs with higher BET surface and larger quantity.

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.