Elsevier

Electrochimica Acta

Volume 117, 20 January 2014, Pages 26-33
Electrochimica Acta

Effects of thermal treatment on the structural and capacitive properties of polyphenylsilane-derived porous carbon nanofibers

https://doi.org/10.1016/j.electacta.2013.11.082Get rights and content

Abstract

Organic-inorganic hybrid composite carbon nanofibers (CCNFs) are prepared by one-step electrospinning and subsequent thermal treatment using polyphenylsilane (PPS) as an inorganic precursor. We investigate the structural properties and electrochemical behavior of these CCNF materials when applied as supercapacitor electrodes as a function of the carbonization temperature ranging from 800 to 1000 °C. The introduction of PPS induces thermal stability for the organic-inorganic hybrid CCNFs via the incorporation of a porous structure with stabilized functional structures such as silicon oxynitride (SiOxNy) and silicon oxycarbide (SiOxCy). This phenomenon is attributed to the synergistic effect of both the double-layer capacitance and the pseudo-capacitive effect induced by the porous carbon layer and the some surface functionalities), thereby providing high charge capacity, power and energy density.

Introduction

Organic/inorganic composite materials have attracted a great deal of attention because of their potential use in many emergent applications, such as in gas storage and gas separation, and as catalytic support, specific adsorbents and electrodes in electric double-layer capacitors or Li-ion batteries [1], [2], [3], [4], [5], [6], [7]. They combine the advantages of the inorganic material (e.g., rigidity, thermal stability) and the organic polymer (e.g., flexibility, dielectric, ductility, and processability) [8]. Moreover, they usually also offer special properties of nanofillers leading to materials with improved properties [9]. Therefore, these hybrid nanocomposite systems may exhibit excellent characteristics in comparison to the properties of either of the pure components due to synergetic effects [10], [11]. Among the advanced organic/inorganic composite materials, one dimensional, polyacrylonitrile (PAN)-based, composite carbon nanofibers (CCNFs) have attracted much attention due to their high specific surface area, good chemical stability, and fabrication simplicity. A simple and low-cost approach for fabricating such nanofibers (NFs) is to utilize electrospinning to prepare carbon-precursor polymer composite NFs and subsequent thermal treatment at elevated temperatures to produce 1D carbon structures with suitable pore size distribution using a simple method without template carbons [12], [13], [14], [15], [16], [17], [18], [19].

In this work, organic-inorganic hybrid CCNFs with silicon oxynitride (SiOxNy) and silicon oxycarbide (SiOxCy) structure are prepared by one-step electrospinning and subsequent thermal treatment at different temperatures using polyphenylsilane (PPS) as an inorganic precursor. PPS represents a new class of polymer, which comprises σ-conjugated polymers with a one-dimensional silicon backbone and organic-substituted side chains having carbon-rich phenyl side groups. PPS have several advantages over other conductive polymers, making them very suitable for the preparation of polymer composites [20], [21], [22], [23]. Among the various organic precursors used to produce CNFs, PAN is considered the best candidate polymer due to its high carbon yield, its flexibility for tailoring the structure of the final CNF into the non-woven web, and its easy electrospinning and carbonization processes. Moreover, PAN-based CNFs can be used directly as electrode materials after thermal treatment, as has been realized with many other polymers [24], [25], [26]. Therefore, this work focuses on the effects of the PPS and variation in the carbonization temperature on the structure and electrochemical performance of the organic-inorganic hybrid CCNFs with SiOxNy and SiOxCy structures.

Section snippets

Materials and Fabrication

PAN, phenylsilane, and dimethylformamide (DMF) were purchased from Aldrich Chemical Co. (USA) and used as received. Electrospinning solutions were prepared by dispersing a given amount of PPS (30 wt% relative to PAN in a 10 wt% PAN solution) in DMF. The PPS (Mw = 1500∼2000 by GPC) was prepared by the catalytic dehydrogenative coupling of phenylsilane (Eq. 1) [22], [23]

The blend solution of PAN and PPS was electrospun into NFs using an electrospinning apparatus. The NFs were stabilized in air at

Results and Discussion

SEM images obtained at low and high magnification produced at carbonization temperatures of 800 °C and 1000 °C are presented in Fig. 1a-c. All of the fibers (Fig. 1a-c) exhibited long and continuous cylindrical morphologies. The average diameter of CNF-800 is about 300 nm and they have a smooth surface (Fig. 1a). PPS/CNF-800 and PPS/CNF-1000 became thinner and their morphologies displayed a wrinkled shape with white spots on the surface of the fiber, as shown in Fig. 1b-c, compared with CNF-800.

Conclusions

Porous CCNFs were obtained by simple thermal treatment of electrospun, PPS-incorporated, PAN-based NFs, thereby removing the need for a time-consuming activation step. The PPS was a key factor affecting the formation of micropores on the outer surface of the fibers, while the functional structures of SiOxCy and SiOxNy improved the performance in terms of the electrochemical capacitor and thermal stability. The organic-inorganic hybrid CCNF electrodes may be more suitable for high power

References (59)

  • S.-S. Tzeng et al.

    Growth of carbon nanofibers on activated carbon fiber fabrics

    Carbon

    (2006)
  • Z. Zhou et al.

    Development of carbon nanofibers from aligned electrospun polyacrylonitrile nanofiber bundles and characterization of their microstructural, electrical, and mechanical properties

    Polymer

    (2009)
  • F. Cesano et al.

    Synthesis of ZnO-carbon composites and imprinted carbon by the pyrolysis of ZnCl2-catalyzed furfuryl alcohol polymers

    Journal of Photochemistry and Photobiology A: Chemistry

    (2008)
  • Z. Ahmad et al.

    Synthesis and characterization of chemically cross-linked polyimide-siloxane hybrid films

    Journal of Non-Crystalline Solids

    (2009)
  • S. Cheng et al.

    Preparation of nonwoven polyimide/silica hybrid nanofiberous fabrics by combining electrospinning and controlled in situ sol–gel techniques

    European Polymer Journal

    (2009)
  • Z. Ryu et al.

    Preparation and characterization of silicon carbide fibers from activated carbon fibers

    Carbon

    (2002)
  • Y.J. Kim et al.

    Easy preparation of nitrogen-enriched carbon materials from peptides of silk fibroins and their use to produce a high volumetric energy density in supercapacitors

    Carbon

    (2007)
  • J.W. Liu et al.

    Synthesis of SiC nanofibers by annealing carbon nanotubes covered with Si

    Chemical Physics Letters

    (2001)
  • A.V. Vasin et al.

    Light-emitting properties of amorphous Si:C:O:H layers fabricated by oxidation of carbon-rich a-Si:C:H films

    Solid State Sciences

    (2009)
  • K. Shimoda et al.

    Influence of surface structure of SiC nano-sized powder analyzed by X-ray photoelectron spectroscopy on basic powder characteristics

    Applied Surface Science

    (2007)
  • E.J. Ra et al.

    High power supercapacitors using polyacrylonitrile-based carbon nanofiber paper

    Carbon

    (2009)
  • E. Frackowiak et al.

    Optimisation of supercapacitors using carbons with controlled nanotexture and nitrogen content

    Electrochimica Acta

    (2006)
  • Y.-H. Lee et al.

    Differentiate the pseudocapacitance and double-layer capacitance contributions for nitrogen-doped reduced graphene oxide in acidic and alkaline electrolytes

    Journal of Power Sources

    (2013)
  • B.-H. Kim et al.

    Thin, bendable electrodes consisting of porous carbon nanofibers via the electrospinning of polyacrylonitrile containing tetraethoxy orthosilicate for supercapacitor

    Electrochemistry Communications

    (2011)
  • J.H. Jang et al.

    Electrochemical capacitor performance of hydrous ruthenium oxide/mesoporous carbon composite electrodes

    Journal of Power Sources

    (2003)
  • Y.-W. Ju et al.

    Electrochemical properties of electrospun PAN/MWCNT carbon nanofibers electrodes coated with polypyrrole

    Electrochimica Acta

    (2008)
  • D. Li et al.

    Electrospinning of Nanofibers: Reinventing the Wheel?

    Advanced Materials

    (2004)
  • D.H. Reneker et al.

    Nanometre diameter fibres of polymer, produced by electrospinning

    Nanotechnology

    (1996)
  • C. Moreno-Castilla et al.

    Synthesis and surface characteristics of silica- and alumina-carbon composite xerogels

    Physical Chemistry Chemical Physics

    (2000)
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