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Hierarchical Core/Shell NiCo2O4@NiCo2O4 Nanocactus Arrays with Dual-functionalities for High Performance Supercapacitors and Li-ion Batteries.

Cheng J, Lu Y, Qiu K, Yan H, Xu J, Han L, Liu X, Luo J, Kim JK, Luo Y - Sci Rep (2015)

Bottom Line: As the SC electrode, they deliver a remarkable specific capacitance of 1264 F g(-1) at a current density of 2 A g(-1) and ~93.4% of capacitance retention after 5000 cycles at 2 A g(-1).When used as the anode for LIBs, a high reversible capacity of 925 mA h g(-1) is achieved at a rate of 120 mA g(-1) with excellent cyclic stability and rate capability.The ameliorating features of the NiCo2O4 core/shell structure grown directly on highly conductive Ni foam, such as hierarchical mesopores, numerous hairy needles and a large surface area, are responsible for the fast electron/ion transfer and large active sites which commonly contribute to the excellent electrochemical performance of both the SC and LIB electrodes.

View Article: PubMed Central - PubMed

Affiliation: Key Laboratory of Advanced Micro/Nano Functional Materials, School of Physics and Electronic Engineering, Xinyang Normal University, Xinyang, P. R. China.

ABSTRACT
We report the synthesis of three dimensional (3D) NiCo2O4@NiCo2O4 nanocactus arrays grown directly on a Ni current collector using a facile solution method followed by electrodeposition. They possess a unique 3D hierarchical core-shell structure with large surface area and dual-functionalities that can serve as electrodes for both supercapacitors (SCs) and lithium-ion batteries (LIBs). As the SC electrode, they deliver a remarkable specific capacitance of 1264 F g(-1) at a current density of 2 A g(-1) and ~93.4% of capacitance retention after 5000 cycles at 2 A g(-1). When used as the anode for LIBs, a high reversible capacity of 925 mA h g(-1) is achieved at a rate of 120 mA g(-1) with excellent cyclic stability and rate capability. The ameliorating features of the NiCo2O4 core/shell structure grown directly on highly conductive Ni foam, such as hierarchical mesopores, numerous hairy needles and a large surface area, are responsible for the fast electron/ion transfer and large active sites which commonly contribute to the excellent electrochemical performance of both the SC and LIB electrodes.

No MeSH data available.


Related in: MedlinePlus

TEM images of(a, b) NiCo2O4 NCAs taken at low- and high-magnifications; (c) NiCo2O4@NiCo2O4 core/shell nanocactus; (d, e) HRTEM image and SAED pattern of the shell in (c); (f) EDS of the shell in (c).
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f4: TEM images of(a, b) NiCo2O4 NCAs taken at low- and high-magnifications; (c) NiCo2O4@NiCo2O4 core/shell nanocactus; (d, e) HRTEM image and SAED pattern of the shell in (c); (f) EDS of the shell in (c).

Mentions: More detailed information about the morphological and structural features of the as-synthesized NiCo2O4 and NiCo2O4@NiCo2O4 NCAs was obtained by TEM, HRTEM and selected-area electron diffraction (SAED), as shown in Fig. 4a displayed the overview of a typical NiCo2O4 nanocactus taken from the Ni substrate (Fig. 3a–c), which consisted of nanoneedles (Fig. 4b). In contrast to NiCo2O4 NCAs, NiCo2O4@NiCo2O4 NCAs had a peculiar core/shell structure with a porous NiCo2O4 shell (∼50 nm thick) surrounding a continuous core (∼40 nm in diameter) (Fig. 4c). A close examination of the shell reveals a number of hairy needles rooted in the core. The HRTEM image (Fig. 4d) presented that the lattice fringes of the shell were ∼0.247 and 0.205 nm, corresponding to the (311) and (400) planes of spinel structured NiCo2O4, respectively. The SAED pattern (Fig. 4e) showed well-defined diffraction rings, indicating the poly-crystalline nature of the cubic phase. These rings can be readily indexed to the (111), (220), (311), (400) and (422) planes of the cubic NiCo2O4 phase, which were consistent with the above XRD results. The EDS spectrum in Fig. 4f showed that the nanostructure consisted of O, Co and Ni, and the atomic ratio of Co to Ni was approximately 2:1.


Hierarchical Core/Shell NiCo2O4@NiCo2O4 Nanocactus Arrays with Dual-functionalities for High Performance Supercapacitors and Li-ion Batteries.

Cheng J, Lu Y, Qiu K, Yan H, Xu J, Han L, Liu X, Luo J, Kim JK, Luo Y - Sci Rep (2015)

TEM images of(a, b) NiCo2O4 NCAs taken at low- and high-magnifications; (c) NiCo2O4@NiCo2O4 core/shell nanocactus; (d, e) HRTEM image and SAED pattern of the shell in (c); (f) EDS of the shell in (c).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4487229&req=5

f4: TEM images of(a, b) NiCo2O4 NCAs taken at low- and high-magnifications; (c) NiCo2O4@NiCo2O4 core/shell nanocactus; (d, e) HRTEM image and SAED pattern of the shell in (c); (f) EDS of the shell in (c).
Mentions: More detailed information about the morphological and structural features of the as-synthesized NiCo2O4 and NiCo2O4@NiCo2O4 NCAs was obtained by TEM, HRTEM and selected-area electron diffraction (SAED), as shown in Fig. 4a displayed the overview of a typical NiCo2O4 nanocactus taken from the Ni substrate (Fig. 3a–c), which consisted of nanoneedles (Fig. 4b). In contrast to NiCo2O4 NCAs, NiCo2O4@NiCo2O4 NCAs had a peculiar core/shell structure with a porous NiCo2O4 shell (∼50 nm thick) surrounding a continuous core (∼40 nm in diameter) (Fig. 4c). A close examination of the shell reveals a number of hairy needles rooted in the core. The HRTEM image (Fig. 4d) presented that the lattice fringes of the shell were ∼0.247 and 0.205 nm, corresponding to the (311) and (400) planes of spinel structured NiCo2O4, respectively. The SAED pattern (Fig. 4e) showed well-defined diffraction rings, indicating the poly-crystalline nature of the cubic phase. These rings can be readily indexed to the (111), (220), (311), (400) and (422) planes of the cubic NiCo2O4 phase, which were consistent with the above XRD results. The EDS spectrum in Fig. 4f showed that the nanostructure consisted of O, Co and Ni, and the atomic ratio of Co to Ni was approximately 2:1.

Bottom Line: As the SC electrode, they deliver a remarkable specific capacitance of 1264 F g(-1) at a current density of 2 A g(-1) and ~93.4% of capacitance retention after 5000 cycles at 2 A g(-1).When used as the anode for LIBs, a high reversible capacity of 925 mA h g(-1) is achieved at a rate of 120 mA g(-1) with excellent cyclic stability and rate capability.The ameliorating features of the NiCo2O4 core/shell structure grown directly on highly conductive Ni foam, such as hierarchical mesopores, numerous hairy needles and a large surface area, are responsible for the fast electron/ion transfer and large active sites which commonly contribute to the excellent electrochemical performance of both the SC and LIB electrodes.

View Article: PubMed Central - PubMed

Affiliation: Key Laboratory of Advanced Micro/Nano Functional Materials, School of Physics and Electronic Engineering, Xinyang Normal University, Xinyang, P. R. China.

ABSTRACT
We report the synthesis of three dimensional (3D) NiCo2O4@NiCo2O4 nanocactus arrays grown directly on a Ni current collector using a facile solution method followed by electrodeposition. They possess a unique 3D hierarchical core-shell structure with large surface area and dual-functionalities that can serve as electrodes for both supercapacitors (SCs) and lithium-ion batteries (LIBs). As the SC electrode, they deliver a remarkable specific capacitance of 1264 F g(-1) at a current density of 2 A g(-1) and ~93.4% of capacitance retention after 5000 cycles at 2 A g(-1). When used as the anode for LIBs, a high reversible capacity of 925 mA h g(-1) is achieved at a rate of 120 mA g(-1) with excellent cyclic stability and rate capability. The ameliorating features of the NiCo2O4 core/shell structure grown directly on highly conductive Ni foam, such as hierarchical mesopores, numerous hairy needles and a large surface area, are responsible for the fast electron/ion transfer and large active sites which commonly contribute to the excellent electrochemical performance of both the SC and LIB electrodes.

No MeSH data available.


Related in: MedlinePlus