Elsevier

Electrochemistry Communications

Volume 11, Issue 9, September 2009, Pages 1729-1732
Electrochemistry Communications

Electrochemical interfacial capacitance in multilayer graphene sheets: Dependence on number of stacking layers

https://doi.org/10.1016/j.elecom.2009.06.034Get rights and content

Abstract

We engineered the number of stacking layers of multilayer graphene sheets by selective post-treatments. The most probable number of layers of graphene was determined according to specific surface area. The interfacial capacitance of multilayer graphene sheets relates to the number of layers. This result is attributed to the dependence of space charge layer capacitance on the number of layers.

Introduction

Graphene-monolayer of carbon atoms arranged in a honeycomb lattice – is a prevalent building block in many carbon materials [1], [2]. As a novel model for theoretical study, unusual electronic properties have been discovered in graphene. Previous studies have shown the dependence of the electronic structure of graphene on its number of layers [3], [4], [5]. Most of these results fall in the topic of nanoelectronics. Electrochemistry, however, fails to play its role until recently [6], [7]. Electrochemical interfacial capacitance, defined as the capacitance per surface area (F m−2), is a function of electric double layer capacitance, which is determined by the electronic structure of specified electrode. Insights into the relationships between number of layers and interfacial capacitance of graphene sheets can provide electrochemical approaches to study the electronic structure of graphene and optimize the capacitance of graphene materials as supercapacitor electrode.

Up to date, many efforts have been devoted to the interfacial capacitance of carbon electrodes. The higher interfacial capacitance on edge plane than basal plane of bulk graphite was observed years ago [8]. New insights are recently thrown into the effects of surface chemistry (boron [9], oxygen [10], nitrogen [11], [12] and phosphorus [13]) and micropore size on interfacial capacitance of diverse carbon electrodes [14], [15], [16]. Besides, the interfacial capacitance of porous carbon electrode is limited as the pore wall thickness is reduced [17]. We herein address the dependence of interfacial capacitance on number of layers of multilayer graphene sheets.

Section snippets

Experimental

Reduced graphene oxide sheets were chemically exfoliated from natural flake graphite powder (Sinopharm Chemical Reagent Co. Ltd.) [18]. Post-treatments in argon (g), hydrogen (g), ammonia (g) and hydrazine (l) were performed to modify the surface chemical environment of reduced graphene oxide sheets and hence tailor the stacking thickness. Gaseous treatments were conducted at 400 °C for 4 h, while liquid treatment was refluxed at 100 °C for 24 h. The samples are denoted as r-GO (reduced graphene

Surface chemistry and physical texture characterizations

XPS reveals a decreased oxygen atomic concentration in the sequence of r-GO > GAr  GHy > GH > GN (Table 1). Hydrazine is considered to unlikely reduce carboxylic groups but can react with lactones and anhydrides to form hydrazides and with quinones to form hydrazones [19], [20]. However, it is believed that only the formation of hydrazone can remove oxygen [19]. Oxygen groups can be removed by thermal treatment [21]. Ammonia can be thermally decomposed to yield atomic hydrogen for oxygen removal [22].

Conclusions

In this contribution, we engineered the number of layers of graphene sheets by selective treatments. The number of layers of graphene was determined according to specific surface area. The interfacial capacitance of multilayer graphene sheets is found to depend on the number of layers. This result is attributed to the dependence of space charge layer capacitance of graphene on the number of layers, where the two factors of screening length and stacking thickness play dominantly. This work opens

Acknowledgement

This work was supported by the NSFC grants (Nos. 50872136, 90606008, and 50632040), MOST of China (No. 2006CB932703), and Chinese Academy of Sciences (No. KJCX2-YW-M01).

References (23)

  • O. Barbieri et al.

    Carbon

    (2005)
  • Z.S. Wu et al.

    Carbon

    (2009)
  • S. Stankovich et al.

    Carbon

    (2007)
  • M.J. Bleda-Martinez et al.

    Carbon

    (2006)
  • S. Maldonado et al.

    Carbon

    (2006)
  • K.S. Novoselov et al.

    Science

    (2004)
  • D. Li et al.

    Science

    (2008)
  • T. Ohta et al.

    Science

    (2006)
  • T. Ohta et al.

    Phys. Rev. Lett.

    (2007)
  • F. Giannazzo et al.

    Nano Lett.

    (2009)
  • S.R.C. Vivekchand et al.

    J. Chem. Sci.

    (2008)
  • Cited by (157)

    • Bioinspired GO/Au nanocomposite synthesis: Characteristics and use as a high-performance dielectric material in nanoelectronics

      2022, South African Journal of Botany
      Citation Excerpt :

      It's also a good dielectric substance that aids in the design of electronics and large-scale power systems. GO also has good electrocatalytic characteristics, as well as a high electrochemical capacitance and increased chemical activity (Dreyer et al., 2010; Tang et al., 2009; Wang et al., 2010; Shao et al., 2010; Wang et al., 2009). Low losses and high permittivity dielectric materials were required to make capacitors that could store more electrical energy.

    • Manganese Oxides-Graphene Nanocomposites as Advanced Supercapacitors

      2022, Encyclopedia of Energy Storage: Volume 1-4
    View all citing articles on Scopus
    View full text