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Copper nanofiber-networked cobalt oxide composites for high performance Li-ion batteries.

Nam SH, Kim YS, Shim HS, Kim JG, Bae Kim W - Nanoscale Res Lett (2011)

Bottom Line: We prepared a composite electrode structure consisting of copper nanofiber-networked cobalt oxide (CuNFs@CoOx).The copper nanofibers (CuNFs) were fabricated on a substrate with formation of a network structure, which may have potential for improving electron percolation and retarding film deformation during the discharging/charging process over the electroactive cobalt oxide.Such enhanced Li-ion storage performance may be associated with modified electrode structure at the nanoscale, improved charge transfer, and facile stress relaxation from the embedded CuNF network.

View Article: PubMed Central - HTML - PubMed

Affiliation: School of Materials Science and Engineering, Gwangju Institute of Science and Technology (GIST), 261 Chemdan-gwagiro, Buk-gu, Gwangju 500-712, South Korea. wbkim@gist.ac.kr.

ABSTRACT
We prepared a composite electrode structure consisting of copper nanofiber-networked cobalt oxide (CuNFs@CoOx). The copper nanofibers (CuNFs) were fabricated on a substrate with formation of a network structure, which may have potential for improving electron percolation and retarding film deformation during the discharging/charging process over the electroactive cobalt oxide. Compared to bare CoOxthin-film (CoOxTF) electrodes, the CuNFs@CoOxelectrodes exhibited a significant enhancement of rate performance by at least six-fold at an input current density of 3C-rate. Such enhanced Li-ion storage performance may be associated with modified electrode structure at the nanoscale, improved charge transfer, and facile stress relaxation from the embedded CuNF network. Consequently, the CuNFs@CoOxcomposite structure demonstrated here can be used as a promising high-performance electrode for Li-ion batteries.

No MeSH data available.


Related in: MedlinePlus

FESEM images of the cycled CoOxelectrodes. (a) without and (b) with the Cu NFs after 30th cycle. The tested electrodes were disassembled and extracted from the Li-ion cell.
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Figure 6: FESEM images of the cycled CoOxelectrodes. (a) without and (b) with the Cu NFs after 30th cycle. The tested electrodes were disassembled and extracted from the Li-ion cell.

Mentions: Figure 6 shows the FESEM images of the CoOxTF and CuNFs@CoOxafter the 30th cycle. Two samples were disassembled after the electrochemical cycles in order to characterize the changes in the morphology. The CoOxTF appeared to experience serious cracking and crumbling, as shown in Figure 6a, while the CuNFs@CoOxseemed to remain fairly stable, as shown in Figure 6b. The CuNFs@CoOxmaintained the integrity of the electrode with the current collector, suggesting the composite has the greater stress relaxation than the bare CoOxTF despite its higher capacity. This result implies that the embedded CuNF network significantly compensates the generated stress compared with the CoOxTF without the nanostructure. Thus, our results support the conclusion that embedded CuNF network nanostructures can significantly improve the capacity, rate performance, and mechanical stability of the CoOxelectrode materials.


Copper nanofiber-networked cobalt oxide composites for high performance Li-ion batteries.

Nam SH, Kim YS, Shim HS, Kim JG, Bae Kim W - Nanoscale Res Lett (2011)

FESEM images of the cycled CoOxelectrodes. (a) without and (b) with the Cu NFs after 30th cycle. The tested electrodes were disassembled and extracted from the Li-ion cell.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3211358&req=5

Figure 6: FESEM images of the cycled CoOxelectrodes. (a) without and (b) with the Cu NFs after 30th cycle. The tested electrodes were disassembled and extracted from the Li-ion cell.
Mentions: Figure 6 shows the FESEM images of the CoOxTF and CuNFs@CoOxafter the 30th cycle. Two samples were disassembled after the electrochemical cycles in order to characterize the changes in the morphology. The CoOxTF appeared to experience serious cracking and crumbling, as shown in Figure 6a, while the CuNFs@CoOxseemed to remain fairly stable, as shown in Figure 6b. The CuNFs@CoOxmaintained the integrity of the electrode with the current collector, suggesting the composite has the greater stress relaxation than the bare CoOxTF despite its higher capacity. This result implies that the embedded CuNF network significantly compensates the generated stress compared with the CoOxTF without the nanostructure. Thus, our results support the conclusion that embedded CuNF network nanostructures can significantly improve the capacity, rate performance, and mechanical stability of the CoOxelectrode materials.

Bottom Line: We prepared a composite electrode structure consisting of copper nanofiber-networked cobalt oxide (CuNFs@CoOx).The copper nanofibers (CuNFs) were fabricated on a substrate with formation of a network structure, which may have potential for improving electron percolation and retarding film deformation during the discharging/charging process over the electroactive cobalt oxide.Such enhanced Li-ion storage performance may be associated with modified electrode structure at the nanoscale, improved charge transfer, and facile stress relaxation from the embedded CuNF network.

View Article: PubMed Central - HTML - PubMed

Affiliation: School of Materials Science and Engineering, Gwangju Institute of Science and Technology (GIST), 261 Chemdan-gwagiro, Buk-gu, Gwangju 500-712, South Korea. wbkim@gist.ac.kr.

ABSTRACT
We prepared a composite electrode structure consisting of copper nanofiber-networked cobalt oxide (CuNFs@CoOx). The copper nanofibers (CuNFs) were fabricated on a substrate with formation of a network structure, which may have potential for improving electron percolation and retarding film deformation during the discharging/charging process over the electroactive cobalt oxide. Compared to bare CoOxthin-film (CoOxTF) electrodes, the CuNFs@CoOxelectrodes exhibited a significant enhancement of rate performance by at least six-fold at an input current density of 3C-rate. Such enhanced Li-ion storage performance may be associated with modified electrode structure at the nanoscale, improved charge transfer, and facile stress relaxation from the embedded CuNF network. Consequently, the CuNFs@CoOxcomposite structure demonstrated here can be used as a promising high-performance electrode for Li-ion batteries.

No MeSH data available.


Related in: MedlinePlus