Mesoporous graphitized Ketjenblack as conductive nanofiller for supercapacitors

doi:10.1016/j.matlet.2013.07.121

Materials Letters

Volume 110, 1 November 2013, Pages 105-107

https://doi.org/10.1016/j.matlet.2013.07.121 Get rights and content

Highlights

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Capacitances of supercaps (SCs) with graphitized Ketjenblack (MKB) were examined.
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SC containing MKB have high energy density and high anode capacitance (181 F g⁻¹).
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SC containing MKB retained its high capacitance better at higher scan rates.

Abstract

This study presents the capacitive behavior of a supercapacitor (SC) having mesoporous graphitized Ketjenblack (KB) (modified KB (MKB)) as a conductive nanofiller in its polarized electrodes. Galvanostatic charge/discharge and cyclic voltammogram tests were conducted for SCs containing MKB and normal KB (for reference). The SC containing MKB required long charging periods under constant-current charging. This was due to its higher energy density and anode capacitance (181 F g⁻¹), as compared to that of the SC containing KB. Moreover, the SC containing MKB retained its high capacitance better at higher scan rates.

Graphical abstract

This study examined the specific capacitances of supercapacitors (SCs) with mesoporous graphitized Ketjenblack (KB) (modified KB (MKB)) as conducting nanofiller in polarized electrodes. SC containing MKB required long charging periods under constant-current charging. This result shows high energy density and comparatively higher anode capacitance (181 F g⁻¹). Moreover, SC containing MKB retained its high capacitance better at higher scan rates.

Introduction

Studies on electrochemical supercapacitors (SCs) [1] as a substitute for secondary batteries are being persistently conducted in many countries. Nevertheless, the energy densities of SCs have not met expectations. To improve their performance, various approaches such as the use of carbon nanotubes [2], and other nano-structured materials [3] were developed. In our recent study, we modified SCs having aqueous or organic electrolytes by adding Ketjenblack (KB) to their activated-carbon electrodes as a conductive nanofiller [4]. In this paper, we prepared a mesoporous graphitized KB called modified KB (MKB) and studied its effect as a nanofiller on the anode and cathode capacitances of a SC. We also investigated the specific capacitance of the SC as a function of the scan rate.

Section snippets

Experimental

Preparation of MKB: Normal KB (Lion Corporation, Japan, EC-600JD) powders were placed into an oven (FVHP, Fuji Dempa Co. Ltd., Japan) and subjected to a vacuum of 0.1 Pa. Then, argon gas was introduced into the oven at 0.1 MPa. After that, the inner temperature of the oven was increased to 1300 °C at a rate of 10 °C min⁻¹. The high temperature was maintained in the oven for 12 h. Finally, the oven was switched off, and the graphitized KB (MKB) was recovered after cooling.

Carbon-black characterization

Results and discussion

Carbon-black characterization: Fig. 1 shows TEM images of the MKB samples used in this study. A typical low-magnification image of the samples is shown in the inset. The particles of MKB were graphitized (also see low-magnification inset in Fig. 1), and the typical distance between the graphene layers (002) was ~0.34 nm. Table 1 lists the BET surface area S_BET, micropore volume V_micro, and mesopore volume, V_meso of the samples obtained from the nitrogen adsorption–desorption isotherms of KB and

Conclusions

In this study, the specific capacitances of SCs having an aqueous electrolyte and KB or MKB as a conductive nanofiller, were analyzed by galvanostatic charge/discharge tests and CV, respectively. The specific capacitance and capacity retention of the SC having MKB were superior to those of the SCs having KB.

Acknowledgments

This work was partly supported by the Scientific Research Grant from the Japan Society for the Promotion of Science; the Program to Disseminate Tenure Tracking System from the Japanese Ministry of Education, Culture, Sports, Science and Technology; and a grant for Scientific Research on Priority Areas from the University of Miyazaki.

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NaCl adsorption in multi-walled carbon nanotubes
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Facile preparation of mesoporous carbons for supercapacitors by one-step microwave-assisted ZnCl₂ activation
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D. Tashima et al.
Evaluation of electric double layer capacitor using Ketjenblack as conductive nanofiller
Electrochimica Acta
(2011)

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Mesoporous graphitized Ketjenblack as conductive nanofiller for supercapacitors

Highlights

Abstract

Graphical abstract

Introduction

Section snippets

Experimental

Results and discussion

Conclusions

Acknowledgments

Electrochemical supercapacitors: scientific fundamentals and technological applications

NaCl adsorption in multi-walled carbon nanotubes

Materials Letters

Facile preparation of mesoporous carbons for supercapacitors by one-step microwave-assisted ZnCl2 activation

Materials Letters

Evaluation of electric double layer capacitor using Ketjenblack as conductive nanofiller

Electrochimica Acta

Facile preparation of mesoporous carbons for supercapacitors by one-step microwave-assisted ZnCl₂ activation