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Changes in the fractal and electronic structures of activated carbons produced by ultrasonic radiation and the effect on their performance in supercapacitors

Venhryn B., Grygorchak I., Stotsko Z., Kulyk Y., Mudry S., Strelchuk V., Budzulyak S., Dovbeshko G., Fesenko O.

Archives of Materials Science and Engineering

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2012

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Vol. 57, nr 1

28-37

EN

Purpose: Effect of ultrasonic irradiation on change of electron structure as well as fractal one of activated carbons and motivation that these changes are most responsible for the improvement of functional parameters in supercapacitors, were the aim of this paper. Design/methodology/approach: Experimental studies were carried out by means of impedance spectroscopy, cyclic voltammetry, X-Ray diffraction, small angle X-Ray diffraction, X-Ray photoelectron spectroscopy, IR-spectroscopy, Micro-Raman spectroscopy and galvanostatic cycling methods. Findings: Ultrasonic modification of carbon is effective method to increase the specific capacitance as well as power of carbon-based supercapacitors. Changes of parameters of double electric layer are tightly related with change of fractal dimension and allow increasing the percolate mobility of charge carries. Research limitations/implications: This research is a complete and accomplished work. Practical implications: Carbon materials, modified by ultrasonic irradiation, can be used as promising electrode materials in energy storage devices of new generation. Originality/value: This work is of urgent importance for studying of physical and chemical processes in energy storage systems. It is shown that method of ultrasonic irradiation is highly effective for modification of carbon-based materials as electrodes in supercapacitors.

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Supramolecular complexes C<18-crown-ether-6> and their application in devices for energy generation, storage and transformation

Venhryn B., Stotsko Z., Grygorchak I., Mudry S., Balaban O.

Archives of Materials Science and Engineering

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2011

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Vol. 52, nr 1

18-22

EN

Purpose: Formation of supramolecular complexes C<18-crown-ether-6> and investigation of their electrochemical characteristics was the aim of this paper. An organic receptor is inserted in nano/mesopores of activated carbon of these supramolecular complexes. Design/methodology/approach: Electrochemical studies of supramolecular complexes C<18-crown-ether-6> were carried out by means of impedance spectroscopy, cyclic voltammetry and galvanostatic cycling. Findings: It is shown that Faraday generation of energy occurs at low positive potentials whereas the capacitive storage - at higher potentials. As result the value of specific capacitance for AC of faradaic process 10000 F/g was reached as well as 154 F/g of non-faradaic process, whereas the same parameters for BAC equal 13350 F/g and 80 F/g, respectively. Research limitations/implications: This research is a complete and accomplished work. Practical implications: Supramolecular complexes, obtained in this work, could be regarded as promising electrode materials in devices of energy generation, storage and transformation. Originality/value: This work is of urgent importance for physics and chemistry of energy generation, storage and transformation, because it opens new possibilities to new highly effective electrode materials search and enables to reach a high values of functional characteristics.

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Otrzymywanie i charakterystyka uporządkowanych nanoporowatych materiałów węglowych

Choma J., Jaroniec M., Jedynak A.

Ochrona Środowiska

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2003

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R. 25, nr 4

13-18

PL

W pracy przedstawiono najnowsze wyniki badań dotyczących syntezy i charakterystyki uporządkowanych nanoporowatych węgli. Pierwsze prace na tematu uporządkowanych nanoporowatych węgli ukazały się kilka lat po doniesieniach na temat syntezy uporządkowanych, nanoporowatych krzemionek. W pracach tych pokazano, że uporządkowane mezoporowate krzemionki, tak jak i krzemionkowe koloidalne kryształy mogą być stosowane jako matryce w procesie otrzymywania uporządkowanych nanoporowatych węgli. Inny sposobem otrzymywania takich materiałów węglowych z jednorodnymi mezoporami jest koloidalne odwzorowanie polegające na penetracji mezofazy smoły węglowej (będącej prekursorem węglowym) przez cząstki koloidalnej krzemionki. Metody te pozwalają otrzymać uporządkowane węgle z nanostrukturą o dużej powierzchni właściwej (często przekraczającej 1000 m2/g) i dużej objętości porów (ok. 1,5 cm3/g). Przytoczone w niniejszej pracy wyniki doświadczalne wykazały pełną przydatność dyfrakcji promieniowania rentgenowskiego (XRD), transmisyjnej elektronowej mikroskopii (TEM) i adsorpcji azotu do charakterystyki tych nowych węgli.

EN

This paper presents an account of recent research on the synthesis and characterization of ordered nanoporous carbons. The first papers on ordered nanoporous carbons appeared several years after reporting the self-assembly synthesis of ordered mesoporous silica. These papers showed that ordered mesoporous silicas, as well as siliceous colloidal crystals, can be used as templates to prepare highly ordered nanoporous carbons. Another way for the synthesis of carbons with uniform mesopores is colloidal imprinting, which involves the penetration of colloidal silica into the mesophase pitch used as a carbon precursor. These methods afford ordered carbon nanostructures of a high surface area (often above 1000 m2/g) and high pore volume (about 1.5 cm3/g). An experimental illustration is provided to show the usefulness of powder X-ray diffraction (XRD), transmission electron microscopy (TEM) and nitrogen adsorption for the characterization of these novel carbons.