scholarly journals Continuously Reinforced Carbon Nanotube Film Sea-Cucumber-Like Polyaniline Nanocomposites for Flexible Self-Supporting Energy-Storage Electrode Materials

Nanomaterials ◽  
2021 ◽  
Vol 12 (1) ◽  
pp. 8
Author(s):  
Bingjian Li ◽  
Shi Liu ◽  
Haicun Yang ◽  
Xixi Xu ◽  
Yinjie Zhou ◽  
...  

The charge storage mechanism and capacity of supercapacitors completely depend on the electrochemical and mechanical properties of electrode materials. Herein, continuously reinforced carbon nanotube film (CNTF), as the flexible support layer and the conductive skeleton, was prepared via the floating catalytic chemical vapor deposition (FCCVD) method. Furthermore, a series of novel flexible self-supporting CNTF/polyaniline (PANI) nanocomposite electrode materials were prepared by cyclic voltammetry electrochemical polymerization (CVEP), with aniline and mixed-acid-treated CNTF film. By controlling the different polymerization cycles, it was found that the growth model, morphology, apparent color, and loading amount of the PANI on the CNTF surface were different. The CNTF/PANI-15C composite electrode, prepared by 15 cycles of electrochemical polymerization, has a unique surface, with a "sea-cucumber-like" 3D nanoprotrusion structure and microporous channels formed via the stacking of the PANI nanowires. A CNTF/PANI-15C flexible electrode exhibited the highest specific capacitance, 903.6 F/g, and the highest energy density, 45.2 Wh/kg, at the current density of 1 A/g and the voltage window of 0 to 0.6 V. It could maintain 73.9% of the initial value at a high current density of 10 A/g. The excellent electrochemical cycle and structural stabilities were confirmed on the condition of the higher capacitance retention of 95.1% after 2000 cycles of galvanostatic charge/discharge, and on the almost unchanged electrochemical performances after 500 cycles of bending. The tensile strength of the composite electrode was 124.5 MPa, and the elongation at break was 18.9%.

NANO ◽  
2016 ◽  
Vol 11 (02) ◽  
pp. 1650015 ◽  
Author(s):  
Tingting Chen ◽  
Yong Fan ◽  
Guangning Wang ◽  
Jing Zhang ◽  
Huixin Chuo ◽  
...  

The composite supercapacitor electrodes were rationally fabricated by facile electrochemical deposition of polypyrrole (PPy) on NiCo2O4 nanowire arrays which were grown radially on carbon fiber (CF). When used as electrodes in supercapacitors, the composite nanostructures demonstrated prominent electrochemical performances with a high areal capacitance (1.44[Formula: see text]F/cm2 at a current density of 2[Formula: see text]mA/cm2), a good rate capability (80.5% when the current density increases from 2[Formula: see text]mA/cm2 to 20[Formula: see text]mA/cm2), and a good cycling ability (85% of the initial specific capacitance remained after 5000 cycles at a high current density of 10[Formula: see text]mA/cm2). The excellent electrochemical performance of NiCo2O4@PPy nanostructures can be mainly ascribed to the good electrical conductivity of PPy, the enhanced adherent force between electrode materials and CF to hold the electrode fragments together by means of NiCo2O4 nanowires, the short ion diffusion pathway in ordered porous NiCo2O4 nanowires and the three-dimensional nanostructures.


2009 ◽  
Vol 1173 ◽  
Author(s):  
Hidetoshi Matsumoto ◽  
Kenichi Suzuki ◽  
Kazuma Tsuboi ◽  
Mie Minagawa ◽  
Akihiko Tanioka ◽  
...  

AbstractThermal-stable, conductive, and flexible carbon fabric (CF), which is composed of thin carbon fibers prepared by electrospinning, was used for the substrate of carbon nanotube (CNT) field emitter arrays. The field emitter arrays were prepared by chemical vapor deposition (CVD). The current density-electric field characteristics revealed that the CNT field emitter arrays on CF produced a higher current density at a lower turn-on voltage compared to ones on a Si substrate. This emitter integrated with a gate electrode based on hierarchy-structured carbon materials, CNTs on CF, can be used for light sources, displays, and other electronic devices.


1994 ◽  
Vol 369 ◽  
Author(s):  
Steen Skaarup ◽  
L.M.W.K. Gunaratne ◽  
Keld West ◽  
Birgit Zachau-Christiansen

AbstractPolyaniline has been synthesized in propylene carbonate by galvanostatic electrochemical polymerization at current densities between 16 and 1000 μA/cm2. Earlier results for polypyrrole have shown that low and high current density films have different properties: The films synthesized at low current density have a higher conjugation length and a more regular structure. The corresponding effect in PANI has been investigated by cyclic voltammetry and UV/visible spectroscopy. Simultaneous measurement of cyclic voltammograms and the absorbtion of selected spectral lines is used because of the complex nature of the PANI system which involves several redox systems as well as forms differing in the degree of protonation and morphology.The main result is that the method of galvanostatic synthesis at low current densities (-16 μA/cm2) produces polyaniline polymers of different, more conjugated and more regular structure than those prepared at higher current densities. The standard method of in situ layer-by-layer polymerization of conducting polymers during cyclic voltammetry often results in uncontrolled and unmeasured current densities of 0.5-2 mA/cm2 which produces a film that probably has a less regular structure containing more deviations from ideality.


2010 ◽  
Vol 97-101 ◽  
pp. 1582-1585 ◽  
Author(s):  
Yan Hong Tian ◽  
Bo Rong Wu ◽  
Ding Wen Mao

Activated carbon (AC)/polyaniline (PANI) composite electrode materials were synthesized in this article. The effect of preparation such as BET surface area and porous size of AC on the electrochemical performances of AC/PANI composite material was investigated. The electrochemical performances of the composite were tested with cyclic voltammetry, galvanostatic charge-discharge and electrochemical impedance spectrometry in 6mol/L KOH solution using Hg/HgO as reference electrode. Composite surface morphology was examined by scanning electron microscope (SEM). The result shows that when the ratio of AC to aniline increases, the conversion of aniline and the capacitance value of composite also increase in keeping the ratio of AC to aniline constant. When AC: aniline : (NH4)2S2O8 =7:1:1, the conversion of aniline up to more than 95% and the capacitance value of electrode materials increased from 239F/g(pure AC) to 409F/g, which is 71.1% higher than pure AC. Pore structure of AC also has great effect on electrochemical performances of electrode material. With the increase of proportion of mesoporous, the electrochemical properties of composite are greatly increased.


Author(s):  
Kazuhiko Sasagawa ◽  
Kazuhiro Fujisaki ◽  
Jun Unuma ◽  
Ryota Azuma

Carbon nanotube (CNT) has a great tolerance to high current density which is a cause of electromigration (EM). Therefore, CNT is expected to use as the materials of nanoscale components of electronic devices. The damage mechanisms of CNT are regarded as the effects of oxidation by Joule heating and/or the EM by high-density electron flows. In this study, we investigated the damage mechanism of CNT structures used as nano-component of electronic devices. An EM acceleration testing system was designed using the CNT structures collected at the gap of thin-film electrodes. The EM tests were conducted under the several kinds of current density conditions and the surrounding environments. An indicator of lifetime was determined by voltage measurements during the acceleration tests and their fracture phenomena were evaluated by means of microscopic observations. As the results, the amounts of lifetime of CNT were longer in the lower oxygen concentrations than in the air condition. In the microscopic studies, it was confirmed that the local evaporation of carbon atoms due to oxidation appeared at the cathode side of the CNT structures under low current density, and the center area of CNT under high current density. Both types of damage morphologies induced by oxidation and EM were observed at the damaged CNT. The results showed the dominant damage mechanism alternated between oxidation and EM depending on current density under oxygen rich conditions.


2015 ◽  
Vol 723 ◽  
pp. 615-618
Author(s):  
Li Lai Liu ◽  
Hai Jiao Zhang ◽  
Shuang Li ◽  
Chao Yang ◽  
Pei Xia Yang

Graphene oxide is prepared by modified Hummers method with the expanded graphite prepared from large flake graphite as raw material. The large tracts of graphene sheets prepared by ascorbic acid chemical reduction of graphite oxide are characterized by scanning electron microscope and X-ray diffraction. The electrochemical performances of graphene sheets are studied successively. The results show that large tracts of graphene sheets as an anode for lithium-ion batteries exhibits a high capacity of 1693 mAh·g-1 after initial discharge at a current density of 100 mA·g-1 and remains 426 mAh·g-1 after 100 cycles. The graphene sheets show good cycling stability even at high current density. The reversible specific capacities remains 218 mAh g-1 at the current densities of 1000 mA g-1 after 100 cycles.


2020 ◽  
Vol 10 (10) ◽  
pp. 1685-1691
Author(s):  
Lingfang Li ◽  
Dan Chen ◽  
Sichao Su ◽  
Bin Zeng

At present, due to the depletion of fossil fuels and increasingly serious environmental problems, more and more attention has been paid to the development and application of functional nanostructured materials as renewable energy storage materials. Herein, lithium and sodium storage properties of hard carbons (HC) prepared by pyrolyzing cellulose were investigated. The orderliness and bonding mode of hard carbon were analyzed by X-Ray Diffraction and X-ray Photoelectron Spectroscopy. Electrochemical properties were characterized by Cyclic Voltammetry, electrochemical Impedance Spectroscopy and charge–discharge test. Results showed that the cellulose-derived hard carbon had good lithium and sodium storage performance. The charge–discharge capacity was about 400 mAh/g and 240 mAh/g, respectively, at a current density of 0.2 A/g, and capacity was also stable under high current density of 2 A/g.


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