Elsevier

Applied Surface Science

Volume 307, 15 July 2014, Pages 172-177
Applied Surface Science

Preparation of polyaniline/graphene oxide nanocomposite for the application of supercapacitor

https://doi.org/10.1016/j.apsusc.2014.04.007Get rights and content

Highlights

  • Different PANI/GO nanocomposites were prepared through chemical polymerization method.

  • We found the unique morphology of Mace-like PANI/GO composite when the mass ratio (mANI:mGO) was 1000:1.

  • The Mace-like PANI/GO nanocomposite has a high specific capacitance (355.2 F g−1 at 0.5 A g−1).

  • The Mace-like PANI/GO nanocomposite exhibited the excellent electrochemical stability even after 1000 cycles.

Abstract

Graphene oxide was synthesized by an improved Hummers method. Three polyaniline (PANI)/graphene oxide (GO) nanocomposite electrode materials were prepared from aniline (ANI), GO, and ammonium persulfate (APS) by chemical polymerization with the mass ratio (mANI:mGO) 1000:1, 100:1, and 10:1 in ice water, respectively. The crystal structure and the surface topography of all materials were characterized by means of X-ray diffraction (XRD), Fourier transform infrared spectrum (FT-IR) and scanning electron microscopy (SEM). The electrochemical properties of the composite were evaluated by cyclic voltammetry, galvanostatic charge/discharge, and the impedance spectroscope, respectively. The test results show that the composites have similar and enhanced cyclic voltammetry performance compared with pure PANI based electrode material. The PANI/GO composite synthesized with the mass ratio (mANI:mGO) 1000:1 possessed excellent capacitive behavior with a specific capacitance as high as 355.2 F g−1 at 0.5 A g−1 in 1 mol L−1 H2SO4 electrolyte due to the unique morphology of Mace-like PANI/GO composite, and after 1000 cycles, the specific capacitance of the composite still has 285.8 F g−1. These results demonstrate exciting potentials of the composite for high performance supercapacitors or other power source system.

Introduction

Electrochemical capacitors (often called supercapacitors) are novel energy storage systems that have been applied in many fields because of their long cycle-life, excellent reversibility and high power density [1], [2], [3]. However, their widespread use is limited by their lower energy storage density and relatively higher effective series resistance than that of batteries. Therefore, many researchers in this area have focused on the development of different electrode materials such as various forms of carbon, conducting polymers, and transition metal oxides [4], [5], [6]. Electrically conducting polymers have attracted worldwide research interest because of their high flexibility and relatively high specific capacitance as one of the main electrode materials for supercapacitors. Among various polymers, polyaniline (PANI) is extremely attractive as electrode materials for supercapacitors due to high electrochemical activity, chemical stability and ease of synthesis as well as relatively low cost [7], [8], [9]. But it can produce volume expansion and contraction sometimes, low intensity of cycle stability, easy to collapse when in charge and discharge [10], [11]. So it is needed to be studied further to improve the cycle performance of PANI electrode materials.

In order to overcome this drawback, all kinds of carbon materials, such as porous carbon [12], mesoporous carbon [13] and carbon nanotube [14], have been investigated due to their good conductivity, stable physicochemical properties, low cost, and long cycle life [1]. Graphene oxide (GO) surface contains a large number of functional groups (carboxyl, hydroxyl, epoxy group, etc.) [15], [16]. These unique functional groups make it good dispersion and hydrophile in the water, which make it as a promising candidate for the fabrication of supercapacitor electrode materials [17], [18]. In addition, graphene oxide also has larger specific surface area, wide chemical potential, excellent chemical stability, and rich drape morphology [19]. It will improve the conductivity and cyclic stability of the electrode after compound graphene oxide to polymer. Therefore, combining nanometer-sized and nanostructured graphene oxide with PANI has been extensively studied. For instance, Wang et al. [20] prepared the nanocomposite with a mass ratio of aniline/graphite oxide, 100:1 and found that the specific capacitance was 531 F g−1 at 0.2 A g−1 in aqueous electrolyte. Xu et al. [21] prepared PANI/GO nanocomposite by in situ polymerization with the assistance of supercritical carbon dioxide (SC CO2) and PANI/GO nanocomposite with aniline concentration at 0.1 mol L−1 exhibited high specific capacitance (425 F g−1) at a current density of 0.2 A g−1.

In the present work, synthesis, chemical structure, and morphology of PANI/GO nanocomposite and electrochemical performances as electrode materials for supercapacitors are investigated.

Section snippets

Materials

All chemical reagents used in this study were of analytical laboratory grade. Aniline monomer was purchased from Tianjin Damao Chemical Reagent Co. Ltd. (Tianjin, China) and vacuum distilled before use to remove impurities. Graphite powder (325 mesh, carbon content 99.95 wt%) was obtained from Aladdin Chemical Reagent Co. Ltd. (Shanghai, China). Hydrochloric acid (HCl), sulphuric acid (H2SO4), nitric acid (HNO3), potassium permanganate (KMnO4), hydrogen peroxide (H2O2) and ammonium

XRD analysis

The crystal structure of graphene oxide, polyaniline, and different PANI/GO composites were characterized by X-ray diffraction (XRD), respectively. The XRD pattern of graphene oxide is shown in Fig. 1. The graphene oxide pattern reveals an intense and sharp peak located at 9.74°, corresponding to the characteristic diffraction peak of GO powder and an interlayer distance of 0.91 nm [23]. The PANI pattern reveals three intense and sharp peak located at 14.7°, 20.2°, and 25.4°, corresponding to (0 1

Conclusions

In summary, we have synthesized different PANI/GO nanocomposite through chemical polymerization method and found Mace-like structure of composite when the mass ratio (mANI:mGO) was 1000:1. In this special structure, PANI could be formed homogeneously on the graphene oxide surface because of the low concentration of functional groups capable of acting as reaction sites, resulting in Mace-like structure. The special structure endows the composite with high specific surface area, resulting in the

Acknowledgements

Support from the National Basic Research Program of China (Program 973) (No. 2011CB605603), the Basic Research Project of Shenzhen (No. JCYJ20120613110532389) is greatly acknowledged.

References (29)

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