Limits...
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: 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.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.

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

(a) CV curves for NiCo2O4@NiCo2O4 NCAs, NiCo2O4 NCAs and pure Ni foam, recorded at a scan of 30 mV s−1; (b, c) CV and galvanostatic charge-discharge curves of the NiCo2O4@NiCo2O4 NCAs at different scan rates and different current densities in 2 M KOH aqueous solution, respectively; (d) galvanostatic charge-discharge curves of the NiCo2O4 NCAs at different current densities.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC4487229&req=5

f6: (a) CV curves for NiCo2O4@NiCo2O4 NCAs, NiCo2O4 NCAs and pure Ni foam, recorded at a scan of 30 mV s−1; (b, c) CV and galvanostatic charge-discharge curves of the NiCo2O4@NiCo2O4 NCAs at different scan rates and different current densities in 2 M KOH aqueous solution, respectively; (d) galvanostatic charge-discharge curves of the NiCo2O4 NCAs at different current densities.

Mentions: Cyclic voltammetry (CV) measurements were performed to examine the electrochemical characteristics and quantify the specific capacitances of the electrodes. Figure 6a showed the CV of the NiCo2O4@NiCo2O4 NCA electrode in comparison with those of the NiCo2O4 NCA and neat Ni foam counterparts at a scan rate of 30 mV s−1. The signal from Ni foam was negligible compared to other CVs. The area integrated within the current-potential curve of the core/shell structured NiCo2O4@NiCo2O4 electrode was remarkably larger than that of the NiCo2O4 electrode, indicating much higher electrochemical reaction activities of the former. The synergy arising from the presence of highly porous NiCo2O4 shell with numerous hairy needles and large surface area appeared to be responsible for the enhanced ion diffusion and fast electron transfer in the NiCo2O4@NiCo2O4 electrode. It is worth noting that the redox peak positions of the two electrode materials are significantly different, possibly ascribed to the difference in electrode polarization behavior during the CV tests. The polarization behavior is closely related to the chemical composition and morphology of the electrode material. The redox reactions in an alkaline electrolyte can be expressed as follows103334:


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)

(a) CV curves for NiCo2O4@NiCo2O4 NCAs, NiCo2O4 NCAs and pure Ni foam, recorded at a scan of 30 mV s−1; (b, c) CV and galvanostatic charge-discharge curves of the NiCo2O4@NiCo2O4 NCAs at different scan rates and different current densities in 2 M KOH aqueous solution, respectively; (d) galvanostatic charge-discharge curves of the NiCo2O4 NCAs at different current densities.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

f6: (a) CV curves for NiCo2O4@NiCo2O4 NCAs, NiCo2O4 NCAs and pure Ni foam, recorded at a scan of 30 mV s−1; (b, c) CV and galvanostatic charge-discharge curves of the NiCo2O4@NiCo2O4 NCAs at different scan rates and different current densities in 2 M KOH aqueous solution, respectively; (d) galvanostatic charge-discharge curves of the NiCo2O4 NCAs at different current densities.
Mentions: Cyclic voltammetry (CV) measurements were performed to examine the electrochemical characteristics and quantify the specific capacitances of the electrodes. Figure 6a showed the CV of the NiCo2O4@NiCo2O4 NCA electrode in comparison with those of the NiCo2O4 NCA and neat Ni foam counterparts at a scan rate of 30 mV s−1. The signal from Ni foam was negligible compared to other CVs. The area integrated within the current-potential curve of the core/shell structured NiCo2O4@NiCo2O4 electrode was remarkably larger than that of the NiCo2O4 electrode, indicating much higher electrochemical reaction activities of the former. The synergy arising from the presence of highly porous NiCo2O4 shell with numerous hairy needles and large surface area appeared to be responsible for the enhanced ion diffusion and fast electron transfer in the NiCo2O4@NiCo2O4 electrode. It is worth noting that the redox peak positions of the two electrode materials are significantly different, possibly ascribed to the difference in electrode polarization behavior during the CV tests. The polarization behavior is closely related to the chemical composition and morphology of the electrode material. The redox reactions in an alkaline electrolyte can be expressed as follows103334:

Bottom Line: 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.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.

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