Elsevier

Chemical Engineering Journal

Volume 356, 15 January 2019, Pages 955-963
Chemical Engineering Journal

A facile dissolved and reassembled strategy towards sandwich-like rGO@NiCoAl-LDHs with excellent supercapacitor performance

https://doi.org/10.1016/j.cej.2018.09.101Get rights and content

Highlights

  • A dissolved and reassembled strategy has been put forward.

  • NiAl-LDHs could act as an accumulator to accommodate Co2+ dissolved from ZIF-67.

  • This strategy could be extended to other electrode materials.

Abstract

Metal organic frameworks hold great potential for high-performance supercapacitors owning to ultrahigh specific surface area and exceptional porosity. Nevertheless, the poor charge transfer kinetics and chemical instability in alkali medium still remain a significant challenge. Herein, a facile dissolved and reassembled strategy towards sandwich-like rGO@NiCoAl-LDHs is proposed to address these drawbacks. NiAl-LDHs can be used as an accumulator to accommodate and reassemble the cobalt ions dissolved from ZIF-67. Graphene could facilitate charge transfer and provide more active sites. Meanwhile, the sandwich-like structure could shorten the transfer distance of electrons and reduce the diffusion resistance of electrolyte. The electrochemical performance is drastically improved due to the enhancement of intrinsic activity reassembling from sandwich-like rGO@ZIF-67@NiAl-LDHs to rGO@NiCoAl-LDHs during cycle process. The electrode material delivers a superior specific capacity of 2291.6 F/g at 1 A/g in a three-electrode configuration. The assembled rGO@NiCoAl-LDHs//AC fulfills a high energy density of 91.4 Wh/kg at a power density of 875 W/kg. In a word, this dissolved and reassembled strategy could possess the huge prospect for energy-related devices.

Graphical abstract

Schematic illustration of the overall dissolution and reassembly during cycle process.

  1. Download : Download high-res image (346KB)
  2. Download : Download full-size image

Introduction

The fascinating properties of metal organic framework (MOF) materials such as exceptional porosity, high surface area and flexible chemical functionality have raised a research boom in recent study [1]. Zeolitic imidazolate framework (ZIF-67), a house-hold subfamily of MOFs, is constructed by cobalt ions and 2-methylimidazole by strong bonds. ZIF-67 has stimulated extensive interest in supercapacitor owing to ultrahigh specific surface area, large internal pore volumes and explicit pore sizes [2], [3], [4], [5]. For instance, Wang et al. have designed hierarchical PANI@CNTs@ZIF-67 on carbon cloth. He manifested that the electrode exhibits a high specific capacity of 3511 mF/cm2 at 0.5 mA/cm2 in 3 M KCl solution [6]. Moreover, MOFs have been served as self-templates to construct various functional nanomaterials ranging from carbon-based materials to metal oxides/sulfides with regular porous structures and rich active centers [7]. As an example, Wu et al. have applied HKUST-1 as a precursor to prepare Cu1.96S/C hybrid composites. Impressively, the as-synthesized composite exhibits high specific capacity and good cycling performance in supercapacitors [8], Zhang et al. have fabricated porous hollow Co3O4 with rhombic dodecahedral structure originating from a ZIF-67-engaged method, which revealed an approving specific capacity of 1100 F/g in 3 M KOH solution [9].

Notwithstanding these appealing features are in this direction, the large-scale application of ZIF-67 in supercapacitors is still hampered by its intrinsical underdeveloped conductivity and chemical instability in alkali medium [10], [11]. ZIF-67-based composites possess relatively low specific capacity or inferior lifespan in alkali electrolyte [12], [13]. Designing an accessibly-manipulated and efficient method to address these issues is of outmost significance for ZIF-67 application in supercapacitors. The capacitive performance can be effectively enhanced by (i) integrating with carbon materials to achieve high conductivity and excellent structure stability; (ii) employing appropriate materials to accommodate and reassemble the cobalt ions dissolved from ZIF-67 during cycle process and (iii) constructing special structures, such as hollow, porous, hierarchical, or sandwich-like structures [14], [15], [16], [17].

Graphene-based carbonaceous materials could offer inherent fast charge transfer and extremely high specific surface area [18], which have been touted as promising electrode materials for supercapacitors [19], [20], [21]. The existence of rGO in the composite can provide a conductive support to promote fast Faradaic charging and discharging of ZIF-67.

Recently, great efforts have been dedicated to utilizing the poor chemical stability in alkali medium [22], [23], where unitary or binary transition metal hydroxides were successfully synthesized through a solid-solid conversion approach with the assistance of alkali medium by engaging MOF as both the precursor and the self-sacrificing template. However, there was no related reference about fabricating an accumulator to accommodate and reassemble the cobalt ions dissolved from ZIF-67 during cycle process, the proposed dissolved and reassembled strategy could effectively improve the utilization of Co2+ and then enhance the electrochemical performance comparing to previous reports. Layered double hydroxides (LDHs), a series of lamellar mixed hydroxides containing brucite-type layers and exchangeable anions [24], [25], have raised a research boom in wide ranges of crucial fields, i.e. catalysis, polymerization and environmental application owing to their outstanding redox property, layered structure, high surface area and tunable composition [26], [27], [28]. In particular, LDHs can be selected as an accumulator because of relatively weak interlayer bonding, as a consequence, they demonstrate outstanding capacity to capture organic and inorganic ions.

Herein, an inspiration about designing sandwich-like rGO@ZIF-67@NiAl-LDHs is emerged in our minds for the first time. Firstly, NiAl-LDHs can be regarded as an accumulator to accommodate the cobalt ions dissolved from ZIF-67. Then, the unique structure could shorten the transfer distance of electrons and lower the diffusion resistance of the electrolyte. In addition, conductive rGO with reasonable electrochemical activities could facilitate charge transfer. As expected, the electrode material exhibits excellent electrochemical performance such as high specific capacity and long-term durability in alkaline medium. This proposed strategy could promote the utilization of MOF in alkali medium and broaden MOFs’ application in energy storage.

Section snippets

Results and discussion

A plausible mechanism to prepare sandwich-like rGO@ZIF-67@NiAl-LDHs is shown in Scheme 1. The GO nanosheets are designed as the deposited substrate and electrons transfer scaffold. Initially, the Co2+ adsorbs on the surface of GO nanosheets and subsequently coordinates with 2-methylimidazole to synthetise ZIF-67. Then, the AlOOH coating onto the rGO@ZIF-67 using a layer-by-layer method provides the aluminum source. At last, the NiAl-LDHs nanosheets distribute evenly onto the surface of

Conclusions

In summary, an overall dissolved and reassembled strategy has been put forward to address the poor chemical stability of ZIF-67 in alkali medium for the first time. Benefiting from the high specific area, enhanced transport of electrons and steady structure, the as-prepared composite can be used as an electrode material for high-performance supercapacitors with a maximum specific capacity of 2291.6 F/g at a current density of 1 A/g. The asymmetric supercapacitor based on rGO@NiCoAl-LDHs

Acknowledgments

This work was financially supported by the NSF of China (21671049, 21371041, 51572063 and 51702071), the Innovative Research Team Foundation of Green Chemical Technology in the University of Hei Longjiang Province, China (2014TD007), the Science and Technology Innovation Foundation of Harbin (2014RFXXJ076), the Heilongjiang Science Foundation (QC2018066), the China Postdoctoral Science Foundation (2016M601414, 2018T110278), and Heilongjiang Postdoctoral Foundation (LBH-TZ1706). In addition,

References (63)

  • A. Jänes et al.

    Characterisation of activated nanoporous carbon for supercapacitor electrode materials

    Carbon

    (2007)
  • W.R. Lin et al.

    Superior performance asymmetric supercapacitors based on flake-like Co/Al hydrotalcite and graphene

    Electrochim. Acta

    (2014)
  • Q.H. Wang et al.

    ZIF-67 derived amorphous CoNi2S4 nanocages with nanosheet arrays on the shell for a high-performance asymmetric supercapacitor

    Chem. Eng. J.

    (2017)
  • Y.F. Tang et al.

    Template-free hydrothermal synthesis of nickel cobalt hydroxide nanoflowers with high performance for asymmetric supercapacitor

    Electrochim. Acta

    (2015)
  • H. Furukawa et al.

    The chemistry and applications of metal-organic frameworks

    Science

    (2013)
  • W. Wang et al.

    Recent progress in metal-organic frameworks for applications in electrocatalytic and photocatalytic water splitting

    Adv. Sci.

    (2017)
  • N.L. Rosi et al.

    Hydrogen storage in microporous metal-organic frameworks

    Science

    (2003)
  • J.R. Li et al.

    Cheminform abstract: selective gas adsorption and separation in metal-organic frameworks

    Chem. Soc. Rev.

    (2009)
  • Y. Gao et al.

    Synthesis of nickel oxalate/zeolitic imidazolate framework-67 (NiC2O4/ZIF-67) as a supercapacitor electrode

    New J. Chem.

    (2014)
  • W. Li et al.

    Polyaniline-carbon nanotubes@zeolite imidazolate framework-67-carbon cloth hierarchical nanostructures for supercapacitor electrode

    Electrochim. Acta

    (2017)
  • W. Xia et al.

    Metal-Organic Frameworks and their derived nanostructures for electrochemical energy storage and conversion

    Energy Environ. Sci.

    (2015)
  • R. Wu et al.

    MOFs-derived copper sulfides embedded within porous carbon octahedra for electrochemical capacitor applications

    Chem. Commun.

    (2015)
  • Y.Z. Zhang et al.

    Porous hollow Co3O4 with rhombic dodecahedral structures for high-performance supercapacitors

    Nanoscale

    (2014)
  • Y.L. Gao et al.

    Synthesis of nickel carbonate hydroxide@zeolitic imidazolate framework-67 (Ni2CO3(OH)2@ZIF-67) for pseudocapacitor

    J. Appl. Electrochem.

    (2015)
  • D.J. Zhang et al.

    A quick synthesis of zeolitic imidazolate framework microflowers with enhanced supercapacitor and electrocatalytic performances

    RSC Adv.

    (2015)
  • Z.C. Xing et al.

    Closely interconnected network of molybdenum phosphide nanoparticles: a highly efficient electrocatalyst for generating hydrogen from water

    Adv. Mater.

    (2014)
  • K. Xiong et al.

    Ni-doped Mo2C nanowires supported on Ni foam as a binder-free electrode for enhancing the hydrogen evolution performance

    J. Mater. Chem. A

    (2015)
  • X.M. Geng et al.

    Three-dimensional structures of MoS2 nanosheets with ultrahigh hydrogen evolution reaction in water reduction

    Adv. Funct. Mater.

    (2014)
  • D.S. Kong et al.

    CoSe2 nanoparticles grown on carbon fiber paper: an efficient and stable electrocatalyst for hydrogen evolution reaction

    J. Am. Chem. Soc.

    (2014)
  • L. Li et al.

    Advances and challenges for flexible energy storage and conversion devices and systems

    Energy Environ. Sci.

    (2014)
  • X. Yang et al.

    Bioinspired effective prevention of restacking in multilayered graphene films: towards the next generation of high-performance supercapacitors

    Adv. Mater.

    (2011)
  • Cited by (125)

    View all citing articles on Scopus
    View full text