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AbstractIn this paper, carbon black was evaluated as a possible

electrode candidate material for electrochemical capacitors.

Mechanical pressing as a fast and easy method was used for electrode

fabrication. Regarding the utility in supercapacitors, the

electrochemical properties of the produced electrode was studied

using cyclic voltammetry (CV) and electrochemical impedance

spectroscopy (EIS) tests in 2 M KCl electrolytes. The results

obtained show that carbon black electrode has a specific capacitance

as high as 33.58 Fg1, in the potential range of -0.15 to 0.55 V (vs.SCE) in 2 M KCl at scan rate of 10 mVs-1. Also, charge/discharge

cycling test shows a good reversibility and confirms that the

electrical resistance would increase after 100 cycles.

KeywordsElectrochemical capacitor, Cyclic voltammetry,Electrochemical impedance spectroscopy

.

I. INTRODUCTIONXPLOSIVE growth in electronic equipments and the

urgent need for electronic and hybrid electronic vehicles

demand for the high power and energy storage devices.

Among different energy storage systems, ultracapacitors arerecognized as highly attractive energy storage devices to

satisfy the above needs [1]. Therefore, many laboratories are

actively engaged in development of well-known type of

supercapacitors, viz., electrochemical double-layer, pseudo

and hybrid supercapacitors. Most research in this area has

been focused on the development of the different electrode

materials such as various forms of carbons, conducting

polymers and transition metal oxides [2].

Carbon black is a high conductive carbon base material that

the key properties of it are considered to be fineness (primary

particle size), structure (aggregate size/shape), porosity, and

surface chemistry [3].

In this paper, mechanical pressing as a fast and easy methodwas used to fabricate carbon black electrodes. The product

was evaluated as a possible candidate electrode for

M. Nasibi is with the Petroleum University of Technology, Abadan,

Islamic Republic of Iran (corresponding author to provide phone: +98 911 370

8480; fax: +98 631 442 3250; e-mail:m_nasibi@yahoo.com).

Gh. Rashed, is the Petroleum University of Technology, Abadan, Islamic

Republic of Iran (e-mail: rashed 545@yahoo.com).

M.A.. Golozar is with the Materials Science and Engineering Department,

Isfahan University of Technology, Isfahan, Islamic Republic of Iran (e-

mail:Golozar@gmail.com).

electrochemical capacitors using electrochemical techniques

including cyclic voltammetry, electrochemical impedance

spectroscopy.

II.EXPERIMENTALA.MaterialsNickel foil (99.99% with 0.125 mm thickness) and

polytetrafluoroethylene (

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pore resistance, efficiency is another important parameter

affecting the capacitance in high sweep rates. As the sweep

rate increases, loss of energy increases and the stored charge

on the electrode surface decreases causing the capacitance to

decrease (Table I). Additionally, CV curves at such a high

scan rate reveal a low current response on voltage reversal at

each end potential. Meanwhile, this low current response on

the voltage reversal represents a high equivalent series

resistance of the electrodes and also the low diffusion ofelectrolyte ions in the electrodes [6].

Fig. 1 capacitance vs. potential curves obtained from different

scan rates of carbon black electrodes.

Fig. 2 Representative cyclic voltammograms obtained from carbon

black electrode at 10mV.s-1 in 2 M KCl electrolyte.

The cyclic stability of supercapacitors is a crucial parameter

for their practical applications. So, the stability of carbon

black electrode was evaluated by repeating the CV tests

between -0.15 and +0.55 V (vs. SCE) using a scan rate of 10

mVs-1, for 100 cycles (Fig. 2). Simultaneously, EIS methodwas used to evaluate the electrode changes (Fig. 3). As shown

in Fig. 3, the point of intersecting with the real axis of Nyquist

curves in the range of high frequency is the equivalent series

resistance. It indicates the total resistance of the electrode, the

bulk electrolyte resistance and the resistance at

electrolyte/electrode interface [2]. According to Fig. 3,

Nyquist plots show a double layer capacitance and shift to

higher impedances, which confirm the higher equivalent series

resistance after 100 cycles. Electrolyte deposition and redox

reactions could be the reasons for this resistance increment.

Fig. 3 EIS curves after and before 100 CV cycles for

Carbon black electrodes.

TABLE I

CAPACITANCE OBTAINED FROM CARBON BLACK ELECTRODES AT

DIFFERENT SCAN RATES IN 2MKCL ELECTROLYTE

10 mV/s 20 mV/s 30 mV/s 50 mV/s 100 mV/s

33.58 24.88 17.95 12.08 6.59

IV. CONCLUSIONSIn summary, electrochemical tests revealed that carbon

black, as electrode material for electrochemical capacitors, has

good electrochemical performance in the potential range of

0.15 to 0.55V (vs. SCE) in 2 M KCl electrolyte. It provides a

double layer capacitance. Carbon black electrode has as high

as 33.58 Fg-1 specific capacitance in 2 M KCl electrolyte at

scan rate of 10 mVs-1and shows a good cycling performance.

ACKNOWLEDGMENT

The authors are thankful to Petroleum University of

Technology, Iran, for financial support of the project.

REFERENCES

[1] K.T. Chau, Y.S. Wong, C.C. Chan, Energy Convers. Manage. 40 (1999)pp. 1021-1039.

[2] Y. Zhang et al., Int. J. Hydrogen Energy 34 (2009) pp. 48894899.[3] A.G. Pandolfo, A.F. Hollenkamp, J. Power Sources 157 (2006) pp. 11

27.

[4] B. Babakhani, D.G. Ivey, J. Power Sources 195 (2010) pp. 21102117.[5] B.E. Conway, W.G. Pell, J. Power Sources 105 (2002) pp. 16981.[6] J. Yan et al., J. Power Sources 194 (2009) pp. 1202-1207.

International Conference on Mechanical, Materials and Automotive Engineering (ICMMAE'2012) April 13-15, 2012 Pattaya

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