共查询到20条相似文献,搜索用时 15 毫秒
1.
A. S. Ermakova A. V. Popova M. Yu. Chayka T. A. Kravchenko 《Russian Journal of Electrochemistry》2017,53(6):608-614
It is shown that the liquid oxidative treatment of microporous active carbon (AC) of the Norit DLC Supra 30 grade by nitric acid in the presence of carbamide results in an increase in the content of hydroxy groups on the AC surface at the practically unchanged content of carboxyl groups. Redox functionalization and appearance of pseudocapacity result in an increase in the carbon electrode capacity by 26%. The surface state of the carbon material is characterized using the infrared spectroscopy and Boehm titrimetry techniques, while the electrochemical characteristics are studied using the method of cyclic voltammetry in 3 M sulfuric acid solution. Studies of degradation of the electrodes of the initial and modified active carbons show that capacity decreases by 3 and 8%, accordingly, after 1 thousand charging–discharge cycles. 相似文献
2.
Hydrous manganese oxide/carbon nanotube composite electrodes for electrochemical capacitors 总被引:2,自引:0,他引:2
A novel type of composite electrode based on hydrous manganese oxide and a single-walled carbon nanotube has been prepared and used in electrochemical capacitors. Cyclic voltammetry, galvanostatic charging/discharging tests and electrochemical impedance measurements were applied to investigate the performance of the composite electrodes with different ratios of hydrous manganese oxide and single-walled carbon nanotube. For comparison, the performance of pure hydrous manganese oxide and pure carbon nanotubes was also studied. In this way, the composite electrode with a 6:4 ratio of hydrous manganese oxide to carbon nanotube was found to be the most promising active material for an electrochemical capacitor, which shows both good capacitance and power characteristics. 相似文献
3.
A. S. Solyanikova M. Yu. Chayka A. V. Boryak T. A. Kravchenko A. V. Glotov I. V. Ponomarenko S. D. Kirik 《Russian Journal of Electrochemistry》2014,50(5):419-428
For composite electrodes based on active carbon DCL Supra 30, ordered mesoporous carbon, and synthetic carbon material Sibunit, the electrical double layer capacitance is studied. The original carbon samples are characterized by the methods of gas adsorption, X-ray diffraction, and transmission electron microscopy. The mesoporous structure of the material synthesized by the template method provides the maximum rate of ion transport in pores and demonstrates an insignificant decrease in the specific capacitance (9.5% in an aqueous electrolyte and 1.1% in an nonaqueous electrolyte) with an increase in the polarizing current. 相似文献
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Emerson C. Rios Alessandra A. Correa Fernando H. Cristovan Leandro A. Pocrifka Adriane V. Rosario 《Solid State Sciences》2011,13(11):1978-1983
Composite electrodes of poly(3,4-ethylenedioxithiophene) and manganese oxide (PEDOT/MnO2) have been prepared by electrodeposition of manganese oxide over PEDOT-modified titanium substrate. The PEDOT layers are deposited on titanium by potentiostatic deposition at 1.4 V and at two different temperatures: 5 and 25 °C (named PEDOT(5) and PEDOT(25), respectively). The electrodes are characterized by field emission gun scanning electron microscopy (FEG-SEM) and their electrochemical performances are evaluated by using cyclic voltammetry (CV) in 1 molL−1 Na2SO4. The results show an improvement in the specific capacitance (Cs) of the oxide due to the presence of the polymer layer. Considering only the MnO2 mass, the Cs values of the electrodes Ti/MnO2, Ti/PEDOT(5)/MnO2 and Ti/PEDOT(25)/MnO2, estimated by the CV technique, are 151, 159 and 199 Fg−1 at 10 mVs−1 respectively. The micrographies of electrodes show that the polymer layer leads to very significant changes in the morphology of the oxide layers, which in turn generates the improvement observed in the capacitive property. 相似文献
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Lei Jiang Jingwang Yan Ying Zhou Lixing Hao Rong Xue Liang Jiang Baolian Yi 《Journal of Solid State Electrochemistry》2013,17(11):2949-2958
Glucose-derived activated carbon (GAC)/reduced graphene oxide (RGO) composites are prepared by pre-carbonization of the precursors (aqueous mixture of glucose and graphene oxide) and KOH activation of the pyrolysis products. The effect of the mass ratio of graphene oxide (GO) in the precursor on the electrochemical performance of GAC/RGO composites as electrode materials for electrochemical capacitors is investigated. It is found that the thermally reduced graphene oxide sheets serves as a wrinkled carrier to support the activated carbon particles after activation. The pore size distribution and surface area are depended on the mass ratio of GO. Besides, the rate capability of GAC is improved by the introduction of GO in the precursor. The highest specific capacitance of 334 F g?1 is achieved for the GAC/RGO composite prepared from the precursor with a GO mass ratio of 3 %. 相似文献
8.
Kado Yuya Soneda Yasushi Hatori Hiroaki Kodama Masaya 《Journal of Solid State Electrochemistry》2019,23(4):1061-1081
Journal of Solid State Electrochemistry - Electrochemical capacitors are high-power energy storage devices having long cycle durability in comparison to secondary batteries. The energy storage... 相似文献
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Gelines Moreno-Fernández Christoph Schütter José M. Rojo Stefano Passerini Andrea Balducci Teresa A. Centeno 《Journal of Solid State Electrochemistry》2018,22(3):717-725
This study is essentially based on innovative electrolytes such as the organic salt N-methyl-N-butylpyrrolidinium tetrafluoroborate (Pyr14BF4) dissolved in propylene carbonate (PC) and the pure ionic liquid (N-butyl-N-methyl-pyrrolidinium bis(trifluoromethanesulfonyl)imide (Pyr14TFSI) and its solution in PC. Activated carbon cloths were used as self-standing binder-free electrodes. It is found that the presence of impurities in carbon electrodes may lead to electrolyte decomposition and electrode degradation which notably affect the electrochemical double-layer capacitor (EDLC) performance. Such processes greatly depend on the composition of both the electrode and the electrolyte, being much less significant with solvent-containing electrolytes. By raising the operation temperature to 60 °C, the EDLC performance in the ionic liquid Pyr14TFSI is notably improved due to a relevant decrease in the viscosity and increase in ionic conductivity. By contrast, the presence of impurities, e.g., Zn and Al, in the electrodes remarkably reduces the electrolyte stability and a thick layer of decomposition products completely covers the carbon fibers after cycling at high temperature. The ionic liquid in solution maintains the high maximum operative voltage of the net ionic liquid whereas its viscosity and ionic conductivity are close to those of the conventional Et4NBF4/PC. Furthermore, the presence of propylene carbonate as solvent prevents to some extent the ionic liquid degradation. 相似文献
10.
Min-Jung Jung Euigyung Jeong Seok Kim Sang Ick Lee Jung-Sang Yoo Young-Seak Lee 《Journal of fluorine chemistry》2011,132(12):1127-1133
The surface of phenol-based activated carbon (AC) was fluorinated at room temperature with different F2:N2 gas mixtures for use as an electrode material in an electric double-layer capacitor (EDLC). The effect of surface fluorination on EDLC electrochemical performance was investigated. The specific capacitance of the fluorinated AC-based EDLC was measured in a 1 M H2SO4 electrolyte, in which it was observed that the specific capacitances increased from 375 and 145 F g−1 to 491 and 212 F g−1 with the scan rates of 2 and 50 mV s−1, respectively, in comparison to those of an unfluorinated AC-based EDLC when the fluorination process was optimized via 0.2 bar partial F2 gas pressure. This enhancement in capacitance can be attributed to the synergistic effect of increased polarization on the AC surface, specific surface area, and micro and mesopore volumes, all of which were induced by the fluorination process. The observed increase in polarization was derived from a highly electronegative fluorine functional group that emerged due to the fluorination process. The increased surface area and pore volume of the AC was derived from the physical function of the fluorine functional group. 相似文献
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Srinivasan Sampath Irena Pankratov Jenny Gun Ovadia Lev 《Journal of Sol-Gel Science and Technology》1996,7(1-2):123-128
Several types of amperometric biosensors comprised of immobilized glucose oxidase in chemically-modified ceramic-carbon matrices are compared. The electrodes are comprised of several building blocks each performing a specific function. Glucose oxidase is used to catalyze the bio-oxidation of glucose; carbon powder imparts conductivity and favorable electrochemical characteristics; the Ormosil network provides rigidity and porosity; and the organic modification of the Ormosil imparts controlled surface polarity. Additionally, hydrophilic chemical modifiers are incorporated in order to control the size of the wetted, electroactive layer; high dispersion of inert metal catalysts is used to enhance hydrogen peroxide oxidation and redox mediators may be co-immobilized when oxygen independent response is desirable. The electrodes can be prepared either in the form of thick supported film, useful for disposable electrodes or as bulk-modified, disk shape electrodes, which can be used as renewable surface electrodes. 相似文献
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T. A. Pisareva E. V. Kharanzhevskii S. M. Reshetnikov 《Russian Journal of Electrochemistry》2016,52(8):762-769
The electric capacity of electrochemical capacitors with composite electrodes obtained by laser microstructuring was studied. The obtained electrodes allowed control of the contribution of the resistance of the electrode material and electrolyte to the total equivalent series resistance of the electrochemical capacitor. This allowed us to determine their effect on the resulting characteristics of the capacitors. The dependences of the specific electric capacity on the parameters of the composite structure of electrodes were studied, and the optimum parameters were found. 相似文献
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《Electrochemistry communications》2008,10(7):1067-1070
The efficiently hydrothermal route using sucrose without any catalysts is employed to prepare the uniform carbon spheres. The monodisperse 100–150 nm carbon spheres are obtained with the activation treatment in molten KOH. The carbon spheres are characterized by transmission electron microscope, X-ray diffraction, N2 adsorption, Raman spectroscopy and electrochemical techniques. The relationships of specific capacitance and surface properties of carbon spheres are investigated. A single electrode of carbon nanosphere materials performs excellent specific capacitance (328 F g−1), area capacitance (19.2 μF cm−2) and volumetric capacitance (383 F cm−3). 相似文献
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T. I. Abdullin I. I. Nikitina D. G. Ishmukhametova G. K. Budnikov O. A. Konovalova M. Kh. Salakhov 《Journal of Analytical Chemistry》2007,62(6):599-603
Glassy-carbon electrodes (GCEs) are modified with preoxidized multiwalled carbon nanotubes (CNTs). According to the data of atomic force microscopy, the layers of CNTs on GCEs possess a homogeneous nanostructurized surface. The voltammetric properties of a GCE/CNT depend on the modifier load. Guanine and deoxyguanosine monophosphate are strongly adsorbed on GCE/CNT and oxidized at +690 and +930 mV (pH 7.0), respectively. The oxidation current of guanine DNA nucleotides adsorbed on a GCE/CNT is significantly higher for the thermally denaturated biopolymer than for the native one. Our results are of interest for the development of sensors based on the electrochemical properties of nucleic acids. 相似文献
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Electrochemical capacitors (ECs) are a promising technology for energy storage, and future development of sustainable electrode materials is critical to developing these devices. The recent progress and earnest motivation to develop high specific energy capacitors commercially for the emerging market and electronics industry, coupled with the significance and popularity of graphene foam (GF)–based electrode materials in the preparation of functional capacitors have been crucially explored in this review. The review outlines the current disposition and headways in GF-based ECs' technology. Besides, owing to its three-dimensional interconnected hierarchical form alongside the physicochemical distinctions, GF has been regarded as one to curtail some bottlenecks regarding graphene dispersion/restacking in nanocomposite materials. Some of the various techniques to synthesizing high-grade GF that can enable higher energy density of ECs, as well as some key material's features of GF that enhance various performances of the material's composite have also been reviewed. 相似文献
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Dong X Shen W Gu J Xiong L Zhu Y Li H Shi J 《The journal of physical chemistry. B》2006,110(12):6015-6019
We present an in situ reduction method to synthesize a novel structured MnO(2)/mesoporous carbon (MnC) composite. MnO(2) nanoparticles have been synthesized and embedded into the mesoporous carbon wall of CMK-3 materials by the redox reaction between permanganate ions and carbons. Thermogravimetric analysis (TG), X-ray photoelectron spectrum (XPS), X-ray diffraction (XRD), nitrogen sorption, transmission electron microscopy (TEM), and cyclic voltammetry were employed to characterize these composite materials. The results show that different MnO(2) contents could be introduced into the pores of CMK-3 treated with different concentrations of potassium permanganate aqueous solution, while retaining the ordered mesostructure and larger surface area. Increasing the MnO(2) content did not result in a decrease in pore size from the data of nitrogen sorption isotherms, indicating that MnO(2) nanoparticles are embedded in the pore wall, as evidenced by TEM observation. We obtained a large specific capacitance over 200 F/g for the MnC composite and 600 F/g for the MnO(2), and these materials have high electrochemical stability and high reversibility. 相似文献
18.
With MnSO4, NaOH and K2S2O8 as the raw materials, the amorphous and δ-type manganese dioxide (MnO2) is separately prepared by using different chemical precipitation-oxidation methods. The results of charge–discharge and electrochemical impedance spectroscopy (EIS) tests show that (i) the specific capacitance of the amorphous MnO2 reaches to 301.2 F g−1 at a current density of 200 mA g−1 and its capacitance retention rate after 2000 cycles is 97%, which is obviously higher than 250.8 F g−1 and 71% of the δ-type one, respectively; (ii) good electrochemical capacitance properties of the amorphous MnO2 should be contributed to easy insertion/extraction of ions within the material; (iii) when 5 wt% Bi2O3 is coated on the amorphous MnO2, its specific capacitance increases to 352.8 F g−1 and the capacitance retention rate is 90% after 2000 cycles. 相似文献
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Thamarai Devarajan Seiichiro Higashiya Christopher Dangler Manisha Rane-Fondacaro Jeremy Snyder Pradeep Haldar 《Electrochemistry communications》2009,11(3):680-683
A novel oxygen containing spiro ammonium salt, oxazolidine-3-spiro-1’-pyrrolidinium tetrafluoroborate (OPBF4) was synthesized using an innovative technique for use as electrolyte in electrochemical double layer capacitors (EDLC). Comparison of OPBF4 with commercially available, tetraethyl ammonium tetrafluoroborate (TEABF4) showed higher voltage window and higher capacitance for the OPBF4 compound. Moreover, molarity of 3 M was produced with OPBF4 as compared to a maximum of 1.5 M for TEABF4 in acetonitrile (AN). This is especially important to enable the fabrication of higher energy density EDLC. This is the first report of testing OPBF4 compound in an EDLC device, and it qualifies as a reasonable alternative to TEABF4 for high performance ultracapacitors. 相似文献
20.
《Electrochemistry communications》2007,9(6):1239-1241
A new, in situ experimental procedure, which allows in a single step the formation of a metal, e.g., tin, and its operation as reversible alloying–de-alloying electrode in lithium-ion cells, is here reported. The results demonstrate that this procedure has unique advantages not only in terms of fabrication simplicity but also of electrode response. 相似文献