Hierarchical NiCo<sub>2</sub>O<sub>4</sub> nanosheets@hollow microrod arrays for high-performance asymmetric supercapacitors

Lu, Xingwen; Wu, Dong-Jun; Li, Runzhi; Li, Qi; Ye, Shenghua; Tong, Yexiang; Li, Gao‐Ren

doi:10.1039/c3ta14930g

Cited by 488 publications

(225 citation statements)

References 50 publications

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“…[46] In the Ni 2p spectrum, the core level spectrum is reasonably deconvoluted into four peaks. The binding energy at 854.4 and 872.1 eV are in- [47] Twok inds of Co speciesa re also detected in the Co 2p spectrum.S pecifically,t he fitting peaks at the binding energy of 781.2 and 795.9 eV are attributed to Co 2 + ,w hereas the other two fitting peaks at 779.3 and 794.3 eV are ascribed to Co 3 + .T he high-resolution spectrum of the O1 sr egion exhibits three oxygen contributions, marked as O1, O2, and O3. The peak of O1 at 529.3 eV is atypical metal-oxygen bonds, whereas O2 sitting at 530.8 eV is associated with some defect sites, functional groups like hydroxyls, carboxyls,o rs peciesi ntrinsic to the surfaceo ft he spinel.…”

Section: Resultsmentioning

confidence: 83%

Hierarchical ZnCo₂O₄@NiCo₂O₄ Core–Sheath Nanowires: Bifunctionality towards High‐Performance Supercapacitors and the Oxygen‐Reduction Reaction

Huang

Miao

et al. 2015

Chemistry A European J

123

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Increasing energy demands and worsening environmental issues have stimulated intense research on alternative energy storage and conversion systems including supercapacitors and fuel cells. Here, a rationally designed hierarchical structure of ZnCo2 O4 @NiCo2 O4 core-sheath nanowires synthesized through facile electrospinning combined with a simple co-precipitation method is proposed. The obtained core-sheath nanostructures consisting of mesoporous ZnCo2 O4 nanowires as the core and uniformly distributed ultrathin NiCo2 O4 nanosheets as the sheath, exhibit excellent electrochemical activity as bifunctional materials for supercapacitor electrodes and oxygen reduction reaction (ORR) catalysts. Compared with the single component of either ZnCo2 O4 nanowires or NiCo2 O4 nanosheets, the hierarchical ZnCo2 O4 @NiCo2 O4 core-sheath nanowires demonstrate higher specific capacitance of 1476 F g(-1) (1 A g(-1) ) and better rate capability of 942 F g(-1) (20 A g(-1) ), while maintaining 98.9 % capacity after 2000 cycles at 10 A g(-1) . Meanwhile, the ZnCo2 O4 @NiCo2 O4 core-sheath nanowires reveal comparable catalytic activity but superior stability and methanol tolerance over Pt/C as ORR catalyst. The impressive performance may originate from the unique hierarchical core-sheath structures that greatly facilitate enhanced reactivity, and faster ion and electron transfer.

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Section: Resultsmentioning

confidence: 83%

Hierarchical ZnCo₂O₄@NiCo₂O₄ Core–Sheath Nanowires: Bifunctionality towards High‐Performance Supercapacitors and the Oxygen‐Reduction Reaction

Huang

Miao

et al. 2015

Chemistry A European J

123

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“…The Co 2p spectrum (Fig. 6c) [21,22]. The O2 component observed at 531.4 eV ascribed to high number of defect sites with minimum oxygen coordination in the nanomaterial and tiny particle size [22].…”

Section: Resultsmentioning

confidence: 98%

Hierarchical CuCo2O4 nanobelts as a supercapacitor electrode with high areal and specific capacitance

Vijayakumar

Lee

Ryu

2015

Electrochimica Acta

271

109

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“…These analysis results are consistent with the values reported before. [13,57,58] It is clear that the as-fabricated hybrid products possess a mixed chemical composition containing Co 2+ /Co 3+ and Ni 2+ /Ni 3+ , which can pledge abundant active sites and redox reaction for significantly elevating the whole electrochemical performance of the composites electrode.…”

Section: +mentioning

confidence: 99%

A High‐Energy Density Asymmetric Supercapacitor Based on Fe₂O₃ Nanoneedle Arrays and NiCo₂O₄/Ni(OH)₂ Hybrid Nanosheet Arrays Grown on SiC Nanowire Networks as Free‐Standing Advanced Electrodes

Zhao

Yuan

Yang

et al. 2018

Advanced Energy Materials

333

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environmentally friendly energy storage devices. As an emerging energy powering sources, supercapacitors (SCs) hold a vital and individual position owing to their high power density, excellent cycling stability, fast charge/discharge process as well as noticeable reliability, tremendously bridging the gap between rechargeable batteries and traditional capacitors in terms of energy density and power density. [1][2][3][4] Nevertheless, their commercial applications are still seriously impeded since energy densities of SCs are far lagging behind rechargeable batteries. [5,6] In the light of the critical parameters that decide the energy density (E = 1/2CV 2 ) of supercapacitor devices, [7][8][9] substantial efforts have been dedicated to maximizing the energy density via elevating the overall cell voltage (V) and total specific capacitance (C) governed by negative and positive electrodes. Configuration of asymmetric supercapacitors (ASCs) has emerged as a desirable strategy because of the expanded V arised from the absolutely opposite potential window of the two dissimilar electrode materials. [10][11][12] Accordingly, considerable research interest has been invested in constructing highly capacitive negative and positive electrode materials.Until now, transition metal oxides, hydroxides, or phosphides, especially Ni-Co compounds with low cost, natural abundance, and environmentally benign, are mostly employed as positive electrode materials in ASCs because they can present variable oxidation states, favorable electrochemical activity, and large theoretical-specific capacitance based on redox reactions, so they have received extensive attentions as perfect candidates in ASCs. [13][14][15][16][17][18] However, in comparison of the extraordinary advancement obtained by positive electrode materials, the lack of desired negative electrodes restricts the progress of high-performance ASCs. Previously, carbonaceous materials are still the most widely used as negative electrode, giving rise to low-specific capacitance of 100-250 F g −1 . [19][20][21][22][23] In this regard, pseudocapacitive negative electrode materials are proposed to be hopeful alternatives, whereas the restricted studies and poor , even when charging the device within 6.5 s, the energy density can still maintain as high as 45 W h kg −1 at 26.1 kW kg −1 , and the ASC manifests long cycling lifespan with 86.6% capacitance retention even after 5000 cycles. This pioneering work not only offers an attractive strategy for rational construction of high-performance SiC NW-based nanostructured electrodes materials, but also provides a fresh route for manufacturing next-generation high-energy storage and conversion systems.

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Hierarchical NiCo₂O₄ nanosheets@hollow microrod arrays for high-performance asymmetric supercapacitors

Abstract: Novel NiCo2O4 NSs@HNRAs are fabricated via a simple and environmental friendly template-assisted electrodeposition followed by thermal annealing and they exhibit predominant electrochemical properties and long-term cycle stability.

Cited by 488 publications

References 50 publications

Hierarchical ZnCo₂O₄@NiCo₂O₄ Core–Sheath Nanowires: Bifunctionality towards High‐Performance Supercapacitors and the Oxygen‐Reduction Reaction

Hierarchical ZnCo₂O₄@NiCo₂O₄ Core–Sheath Nanowires: Bifunctionality towards High‐Performance Supercapacitors and the Oxygen‐Reduction Reaction

Hierarchical CuCo2O4 nanobelts as a supercapacitor electrode with high areal and specific capacitance

A High‐Energy Density Asymmetric Supercapacitor Based on Fe₂O₃ Nanoneedle Arrays and NiCo₂O₄/Ni(OH)₂ Hybrid Nanosheet Arrays Grown on SiC Nanowire Networks as Free‐Standing Advanced Electrodes

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Hierarchical NiCo2O4 nanosheets@hollow microrod arrays for high-performance asymmetric supercapacitors

Abstract: Novel NiCo2O4 NSs@HNRAs are fabricated via a simple and environmental friendly template-assisted electrodeposition followed by thermal annealing and they exhibit predominant electrochemical properties and long-term cycle stability.

Cited by 488 publications

References 50 publications

Hierarchical ZnCo2O4@NiCo2O4 Core–Sheath Nanowires: Bifunctionality towards High‐Performance Supercapacitors and the Oxygen‐Reduction Reaction

Hierarchical ZnCo2O4@NiCo2O4 Core–Sheath Nanowires: Bifunctionality towards High‐Performance Supercapacitors and the Oxygen‐Reduction Reaction

Hierarchical CuCo2O4 nanobelts as a supercapacitor electrode with high areal and specific capacitance

A High‐Energy Density Asymmetric Supercapacitor Based on Fe2O3 Nanoneedle Arrays and NiCo2O4/Ni(OH)2 Hybrid Nanosheet Arrays Grown on SiC Nanowire Networks as Free‐Standing Advanced Electrodes

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Hierarchical NiCo₂O₄ nanosheets@hollow microrod arrays for high-performance asymmetric supercapacitors

Hierarchical ZnCo₂O₄@NiCo₂O₄ Core–Sheath Nanowires: Bifunctionality towards High‐Performance Supercapacitors and the Oxygen‐Reduction Reaction

Hierarchical ZnCo₂O₄@NiCo₂O₄ Core–Sheath Nanowires: Bifunctionality towards High‐Performance Supercapacitors and the Oxygen‐Reduction Reaction

A High‐Energy Density Asymmetric Supercapacitor Based on Fe₂O₃ Nanoneedle Arrays and NiCo₂O₄/Ni(OH)₂ Hybrid Nanosheet Arrays Grown on SiC Nanowire Networks as Free‐Standing Advanced Electrodes