Lamellar-crossing-structured Ni(OH)2/CNTs/Ni(OH)2 nanocomposite for electrochemical supercapacitor materials

Wang, Hezhong; Wen, Ming; Chen, Shipei; Wu, Qingsheng

doi:10.1016/j.jallcom.2015.05.227

Cited by 28 publications

(15 citation statements)

References 38 publications

(49 reference statements)

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“…1,30,31 These failures have important consequences because solutions with pH > 13 are critically important for the synthesis, characterization, and application of Ni (hydr)oxides. [24][25][26]29,[33][34][35]41 Furthermore, solutions with pH < 9 are also used to synthesize Ni(OH) 2 from Ni metal using a recent dissolution−precipitation approach. 42 compared to experimentally derived electrode potential−pH diagrams or rather to direct measurements of electrochemical stabilities?…”

Section: ■ Introductionmentioning

confidence: 99%

Improved Electrochemical Phase Diagrams from Theory and Experiment: The Ni–Water System and Its Complex Compounds

et al. 2017

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Electrode potential-pH (Pourbaix) diagrams provide a phase map of the most stable compounds of a metal, its corrosion products, and associated ions in solution. The utility of these phase diagrams is that they enable the assessment of electrochemical stabilities, for example, of Ni metal and its derived oxides, hydroxides, oxyhydroxides, against corrosion in aqueous environments. Remarkably, the Ni Pourbaix diagrams reported over the last 50 years are largely inconsistent with various electrochemical observations, which may be attributed to inaccurate experimental free energies of formation (∆ f G)for the complex Ni-based compounds used in producing the available diagrams. Here we show that state-of-the-art density-functional theory (DFT) can be used to obtain accurate ∆ f G values, which lead to Ni Pourbaix diagrams that are more consistent with direct electrochemical exeriments: Electrochemical impedance spectroscopy and surfaceenhanced Raman spectroscopy are used to characterize the electrochemical stabilities of NiO and Ni(OH) 2 formed on Ni, demonstrating the reliability in correction-free first-principles based Pourbaix diagrams. Our results show the importance in applying modern density functionals in combination with experimental advances in aqueous environment compound identification for assessing electrochemical phase stability of materials, which will be useful for the design, synthesis, and selection of corrosionresistant metals, photoabsorbers, and photocatalytic materials.

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Section: ■ Introductionmentioning

confidence: 99%

Improved Electrochemical Phase Diagrams from Theory and Experiment: The Ni–Water System and Its Complex Compounds

et al. 2017

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“…In this study, FCNT/Ni(HCO 3 ) 2 -Ni was prepared via a method similar to that reported in a previous literature . The CNT was surface-treated using the Hummers method to form FCNT . In a typical experiment, FCNT (0.060 g), Ni(NO 3 ) 2 ·6H 2 O (0.29 g), and urea (0.24 g) were dissolved in 12 mL of a mixed solvent under magnetic stirring.…”

Section: Methodsmentioning

confidence: 99%

“…27 The CNT was surface-treated using the Hummers method to form FCNT. 36 In a typical experiment, FCNT (0.060 g), Ni(NO 3 ) 2 •6H 2 O (0.29 g), and urea (0.24 g) were dissolved in 12 mL of a mixed solvent under magnetic stirring. The mixed solution was constituted by ethylene glycol and deionized water with a volume ratio of 7:1.…”

Section: ■ Experimental Sectionmentioning

confidence: 99%

Carbon Nanotubes Coated with NiOOH-Ni Converted from Ni(HCO₃)₂-Ni Nanoflakes for Electrochemical Energy Storage

Wen

Yan

et al. 2020

ACS Appl. Nano Mater.

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A functionalized carbon nanotube (FCNT)/Ni-(HCO 3 ) 2 -Ni nanostructures were synthesized by decorating nanoflaky and mesoporous Ni(HCO 3 ) 2 onto FCNT along with in situ formed reduced metallic Ni for the purpose of constructing an energy-storage system with both high specific capacity and cycling stability. Such flaky nanostructures can significantly increase the contact surface areas between the mesoporous and nanoflaky Ni(HCO 3 ) 2 -Ni and electrolyte, thus immensely reducing the electrolyte-ion diffusion paths and accelerating the electrontransport rates through the use of a FCNT. The in situ reduced metallic Ni atoms are directly contacted with the electrolytes and quickly converted into NiOOH in the alkaline environment. For this reason, the capacity retention of battery-type electrochemical materials can be significantly enhanced, especially at the beginning of cycles. The obtained flaky FCNT/Ni(HCO 3 ) 2 -Ni nanomaterials exhibit excellent electrochemical performances with a high specific capacity of 203 mAh•g −1 at 3 A•g −1 current density for supercapacitor energy-storage systems. An aqueous asymmetric supercapacitor made of FCNT/Ni(HCO 3 ) 2 -Ni//graphene oxide achieves a 132 Wh•kg −1 energy density at 2880 W•kg −1 power density and an excellent cycling stability with 84% after 6000 cycles.

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“…As a result, the composites would show limited promotion of electrochemical performance [10]. The basic coping strategy is based on the transformation of CNTs' surface properties from hydrophobicity to hydrophilicity by introducing oxygenated groups [6,[11][12][13][14][15][16][17][18]. The following composition of hydrophilisationmodified CNTs with Ni(OH) 2 includes two strategies: (i) random mixing of modified CNTs with Ni(OH) 2 in aqueous suspension; (ii) growth of Ni(OH) 2 on the surface of CNTs forming hierarchical nanostructure.…”

Section: Introductionmentioning

confidence: 99%

Building homogeneous nanostructure in Ni(OH) ₂ /MWCNTs composite by electrostatic attraction

Shi

Cui

2019

Micro & Nano Letters

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A facile strategy for the preparation of composites with homogeneous distribution of multi-walled carbon nanotubes (MWCNTs) in Ni(OH) 2 was proposed. The electrostatic attraction between positively charged Ni(OH) 2 monolayer nanosheets and negatively charged MWCNTs was utilised to self-assemble the composites. The results of electrochemical measurement on the composite containing 30 wt% MWCNTs indicated that the homogeneous composition of MWCNTs in composite significantly reduced the electrical resistance and promoted the electrochemical utilisation of Ni(OH) 2. As a result, the composite presented high electrochemical performance: having specific capacitance of 1568.8 F g −1 at low current density of 2.4 A g −1 and keeping a relatively high specific capacitance of 781.8 F g −1 at high current density of 81.7 A g −1. Based on the results in this works, it is hoped that the adopted strategy could provide a promising idea for the preparation of composites with homogeneous distribution of individual components.

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Lamellar-crossing-structured Ni(OH)2/CNTs/Ni(OH)2 nanocomposite for electrochemical supercapacitor materials

Cited by 28 publications

References 38 publications

Improved Electrochemical Phase Diagrams from Theory and Experiment: The Ni–Water System and Its Complex Compounds

Improved Electrochemical Phase Diagrams from Theory and Experiment: The Ni–Water System and Its Complex Compounds

Carbon Nanotubes Coated with NiOOH-Ni Converted from Ni(HCO₃)₂-Ni Nanoflakes for Electrochemical Energy Storage

Building homogeneous nanostructure in Ni(OH) ₂ /MWCNTs composite by electrostatic attraction

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Lamellar-crossing-structured Ni(OH)2/CNTs/Ni(OH)2 nanocomposite for electrochemical supercapacitor materials

Cited by 28 publications

References 38 publications

Improved Electrochemical Phase Diagrams from Theory and Experiment: The Ni–Water System and Its Complex Compounds

Improved Electrochemical Phase Diagrams from Theory and Experiment: The Ni–Water System and Its Complex Compounds

Carbon Nanotubes Coated with NiOOH-Ni Converted from Ni(HCO3)2-Ni Nanoflakes for Electrochemical Energy Storage

Building homogeneous nanostructure in Ni(OH) 2 /MWCNTs composite by electrostatic attraction

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Product

Resources

About

Carbon Nanotubes Coated with NiOOH-Ni Converted from Ni(HCO₃)₂-Ni Nanoflakes for Electrochemical Energy Storage

Building homogeneous nanostructure in Ni(OH) ₂ /MWCNTs composite by electrostatic attraction