Carbon Nanofiber Webs Research Articles

A Review of Electrospun Carbon Fibers as Electrode Materials for Energy Storage

The applications of electrospun carbon fiber webs to the development of energy storages devices, including both supercapacitors and lithium ion batteries (LIB), are reviewed. Following a brief discussion of the fabrication process and characterization methods for ultrafine electrospun carbon fibers, recent advances in their performance as supercapacitors and LIBs anode materials are summarized. Optimization of the overall electrochemical properties of these materials through choice of thermal treatment conditions, incorporation of additional active components (such as carbon nanotubes, metal oxides, and catalysts), and generation of novel fibrous structures (such as core-shell, multi-channel or porous fibers) is highlighted. Further challenges related to improving the conductivity, surface area, and mechanical properties of the carbon nanofiber webs, as well as the scale-up ability of the fabrication technique, are discussed.

High-performance lithium storage in nitrogen-enriched carbon nanofiber webs derived from polypyrrole

Nitrogen-doped carbon nanofiber webs (N-CNFWs) are prepared by direct pyrolyzation of polypyrrole (PPy) nanofiber webs at 600°C. The structure and morphology of N-CNFWs are characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), Fourier-transform infrared spectroscopy (FTIR), Raman spectra and elemental analysis. Both the doped N content and the N existing type in carbon, change with the pyrolysis time. As anode material for lithium-ion battery, the N-CNFWs show high capacity and good rate capability. The reversible capacity is up to 668mAhg−1 at a current density of 0.1Ag−1 and 238mAhg−1 at 5Ag−1, which can be ascribed to the nanofiber structure and high nitrogen content.

Electrospun Carbon Nanofiber Webs with Controlled Density of States for Sensor Applications

Electrospun carbon nanofiber (CNF) webs with controlled density of states (DOS) are synthesized through varying the carbonization conditions to manipulate the concentration of nanosized graphite domains. These materials exhibit adjustable electrochemical activity and biosensitivity: both electron transfer kinetics for various redox systems and direct electron transfer efficiencies with enzymes increase with the DOS of the CNF webs.

Highly conductive, mesoporous carbon nanofiber web as electrode material for high-performance supercapacitors

Polyacrylonitrile/poly(methyl methacrylate) (PMMA) fibers containing graphene are prepared by the electrospinning method, and hierarchical porous carbon nanofibers (CNFs) are obtained after subsequent heat treatment. The hierarchical porous CNFs have an improved structure and properties because of the increased surface area, unique nanotexture and increased electrical conductivity due to the dispersion of graphene. The carbonized fiber exhibits a high surface area (over 500m2g−1) as result of the narrow ultramicro- and mesopore size distributions (centered at approximately 0.7 and 3.7nm, respectively), and a broad mesopore size distribution ranging from 10 to 50nm. The hierarchical pore structures are introduced by the evolution of small gas molecules during the decomposition of the PMMA during heat treatment. The highest specific capacitance of the CNFs is 128Fg−1, and the energy densities are 16.0–21.4Whkg−1 in an aqueous solution and 75.0–58.2Whkg−1 in an organic electrolyte over a power density range of 400–20,000Wkg−1. Under constant current charging/discharging at 1mAcm−2 for 100 cycles, the stability of the CNFs in a 6M KOH aqueous electrolyte decreases by ∼17% compared with the initial specific capacitance value.

Nitrogen‐Doped Porous Carbon Nanofiber Webs as Anodes for Lithium Ion Batteries with a Superhigh Capacity and Rate Capability

Nitrogen-doped carbon nanofiber webs (CNFWs) with high surface areas are successfully prepared by carbonization-activation of polypyrrole nanofiber webs with KOH. The as-obtained CNFWs exhibit a superhigh reversible capacity of 943 mAh g(-1) at a current density of 2 A g(-1) even after 600 cycles, which is ascribed to the novel porous nanostructure and high-level nitrogen doping.

Phenolic-based carbon nanofiber webs prepared by electrospinning for supercapacitors

Phenolic-based carbon nanofiber webs (PCNFWs) were prepared by electrospinning resole-type phenolic resin/PVA blend solution, followed by curing and carbonization. The PCNFWs presented rich micropores and a BET surface area of 416m2/g without any activation process. The electrochemical properties of the PCNFWs were investigated in two- or three-electrode cell. In spite of moderate surface area, the PCNFWs showed excellent capacitance performance. The specific capacitance was up to 171F/g at 5mV/s and remained 84% at 100mV/s. The excellent electrochemical performance was further confirmed through comparison with commercial activated carbon cloth (1201m2/g). The encouraging results showed the potential of the PCNFWs as supercapacitor electrode material.

Activated carbon nanofiber webs made by electrospinning for capacitive deionization

Activated carbon fiber (ACF) webs with a non-woven multi-scale texture were fabricated from polyacrylonitrile (PAN), and their electrosorption performance in capacitive deionization for desalination was investigated. PAN nanofibers were prepared by electrospinning, followed by oxidative stabilization and activation with carbon dioxide at 750–900°C, resulting in the ACF webs that were characterized by X-ray diffraction, Raman spectroscopy, scanning electron microscopy and nitrogen adsorption. The results show that the as-made ACFs have a specific surface area of 335–712m2/g and an average nanofiber diameter of 285–800nm, which can be tuned by varying the activation temperature. With the ACF webs as an electrode, an electrosorption capacity as high as 4.64mg/g was achieved on a batch-type electrosorptive setup operated at 1.6V. The ACF webs made by electrospinning are of potential as an excellent electrode material for capacitive deionization for desalination.

A New Method for Preparing Electrospinning-Derived Carbon Nanofiber Webs with Electrodeposited Sn-Sb Alloy as an Anode Material of Lithium Ion Batteries

Electrospinning is a straightforward and low cost method for producing carbon nanofiber (CNF) webs that have interrelated pores with high surface area. The process begins with electrospinning of polyacrylonitrile (PAN) on a Cu target collector. In current production methods, the PAN nanofiber web is taken off from the collector. But in order to omit extra stages of taking off the web from a conductive collector and later putting it back on, we will try to keep the web remained on the Cu collector plate through the carbonizing heat treatment and the electrodeposition, to later use the plate as the current collector of a LIB anode. This facilitates the handling of CNFs throughout the entire process that is now much more suitable for commercialization. This unique structure is very suitable for anode materials (AMs) of Lithium Ion Batteries (LIBs). It improves the kinetics of charge/discharge cycles by reducing lithium transport paths, and creates more stable electrochemical performance by providing space for volume expansions of lithium insertions in charging cycles. CNF webs can be used as AMs, demonstrating these advantages over conventional carbonaceous materials that have long been used as the preferred choice-in spite of having a comparatively low theoretical capacity. In this study we use the CNF web as a template for electrodepositing Sn-Sb alloy, to create the mentioned structural characteristics in a coated layer of an alloy with a higher capacity. The resulting composite is shown to have a higher capacity than the substrate CNF and a good cycling performance.

Hierarchical activated carbon nanofiber webs with tuned structure fabricated by electrospinning for capacitive deionization

Download options Please wait... Article information DOI https://doi.org/10.1039/C2JM34890J Article type Communication Submitted 24 Jul 2012 Accepted 28 Aug 2012 First published 10 Sep 2012 Download Citation J. Mater. Chem., 2012,22, 21819-21823 BibTex EndNote MEDLINE ProCite ReferenceManager RefWorks RIS Permissions Request permissions Hierarchical activated carbon nanofiber webs with tuned structure fabricated by electrospinning for capacitive deionization G. Wang, Q. Dong, Z. Ling, C. Pan, C. Yu and J. Qiu, J. Mater. Chem., 2012, 22, 21819 DOI: 10.1039/C2JM34890J To request permission to reproduce material from this article, please go to the Copyright Clearance Center request page. If you are an author contributing to an RSC publication, you do not need to request permission provided correct acknowledgement is given. If you are the author of this article, you do not need to request permission to reproduce figures and diagrams provided correct acknowledgement is given. If you want to reproduce the whole article in a third-party publication (excluding your thesis/dissertation for which permission is not required) please go to the Copyright Clearance Center request page. Read more about how to correctly acknowledge RSC content. Search articles by author Gang Wang Qiang Dong Zheng Ling Chao Pan Chang Yu Jieshan Qiu

Solvent-induced porosity control of carbon nanofiber webs for supercapacitor

A simple and scalable method is reported for fabricating a porosity-controlled carbon nanofibers with a skin–core texture by electrospinning a selected blend of polymer solutions. Simple thermal treatment of the electrospun nanofibers from solution blends of various compositions creates suitable ultramicropores on the surface of carbon nanofibers that can accommodate many ions, removing the need for an activation step. The intrinsic properties of the electrode (e.g., nanometre-size diameter, high specific surface area, narrow pore size distribution, tuneable porosity, shallow pore depth, and good ionic accessibility) enable construction of supercapacitors with large specific capacitance (130.7 F g −1), high power (100 kW kg −1), and energy density (15.0 Wh kg −1).

Nanosized anatase titanium dioxide loaded porous carbon nanofiber webs as anode materials for lithium-ion batteries

Nanosized anatase titanium dioxide loaded porous carbon nanofibers (TiO 2/PCNFs) were prepared from electrospun TiO(OAc) 2/PAN/PMMA composite precursor fibers with different amount of PMMA porogen, which were sequentially heat-treated in different environments. Electrochemical measurement results show that these as-prepared TiO 2/PCNFs present higher cyclic reversible capacity than the TiO 2/CNFs counterpart (without PMMA porogen in its precursor fibers). Among the as-prepared TiO 2/PCNFs samples, the representative TiO 2/PCNFs (the mass ratio of PAN to PMMA is 3:1) exhibits the best high-rate performance with a high stable capacity retention about 200 mAhg − 1 at a current density as high as 800 mAg − 1 . This novel TiO 2/PCNFs composite material opens up a promising application in high-power lithium-ion batteries.

Effect of carbon nanofibers on the infiltration and thermal conductivity of carbon/carbon composites

Preforms containing 0, 5, 10, 15 and 20 wt.% carbon nanofibers (CNFs) were fabricated by spreading layers of carbon cloth, and infiltrated using the electrified preform heating chemical vapor infiltration method (ECVI) under atmospheric pressure. Initial thermal gradients were determined. Resistivity and density evolutions with infiltration time have been recorded. Scanning electron microscopy, polarized light micrograph and X-ray diffraction technique were used to analyze the experiment results. The results showed that the infiltration rate increased with the rising of CNF content, and after 120 h of infiltration, the density was the highest when the CNF content was 5 wt.%, but the composite could not be densified efficiently as the CNF content ranged from 10 wt.% to 20 wt.%. CNF-reinforced C/C composites have enhanced thermal conductivity, the values at 5 wt.% were increased by nearly 5.5–24.1% in the X– Y direction and 153.8–251.3% in the Z direction compared to those with no CNFs. When the additive content was increased to 20 wt.%, due to the holes and cavities in the CNF web and between carbon cloth and matrix, the thermal conductivities in the X– Y and Z directions decreased from their maximum values at 5 wt.%.

An enhanced stable-structure core-shell coaxial carbon nanofiber web as a direct anode material for lithium-based batteries

A new core-shell coaxial carbon nanofibers web (C-CNFW), exhibiting high carbon purity (without any binders), structural integrity, enhanced stability under different current loads, long cycling life, large reversible capacity (over 520 mA h g − 1 ), excellent capacity retention and good rate capability, is fabricated by coaxial electrospinning and subsequent carbonization. It is envisaged that the superior electrochemical properties of C-CNFW will make it a promising candidate for the anode material of high-power lithium-ion batteries (LIBs), owing to the unique combinative effects of core carbon material from mineral oil and sheath carbon material from PAN.

Electrocatalytic Properties of Carbon Nanofiber Web–Supported Nanocrystalline Pt Catalyst as Applied to Direct Methanol Fuel Cell

Electrocatalytic Properties of Carbon Nanofiber Web–Supported Nanocrystalline Pt Catalyst as Applied to Direct Methanol Fuel Cell

Study of the mechanical properties of carbon nanofiber reinforced carbon/carbon composites

The effects of carbon nanofibers (CNFs) on the flexural properties and interlaminar shear strength of CNF-reinforced C/C composites are discussed. The results show that the flexural strength, modulus and interlaminar shear strength of the composite containing 5 wt.% CNFs are increased by nearly 21.5%, 33.5% and 40.7%, respectively, compared to that of the composite containing no CNFs. When the additive content is increased to 20 wt.%, due to the holes and cavities in the CNF web and between carbon cloth and matrix, both the flexural properties and interlaminar shear strength decrease from the maximum value with the additive content at 5 wt.%.

Electrochemical Behaviors of PAN/Ag-based Carbon Nanofibers by Electrospinning

In this work, silver nanoparticles-containing polyacrylonitrile (PAN) solutions in N,N-dimethylformamide (DMF) were electrospun to be webs consisting of nanofibers. The inputted voltage and PAN content in the solution were fixed at 15 kV and 10 wt.% in DMF with 10 cm of tip-to-collector distance (TCD). The PAN/Ag nanofiber webs were stabilized by oxidation at 250 °C for 2 h in air and carbonized at 1000 °C for 2 h in N2. The resultant diameter distribution and morphologies of the nanofibers were evaluated by scanning electron microscope analysis. The electrochemical behaviors of the nanofiber webs were also observed by cyclic voltammetry tests. It was found that the presence of silver nanoparticles in carbon nanofiber webs led to the increase of specific capacitance and the decrease of fiber diameters.

A Study on Electrical Resistivity Behaviors of PAN-based Carbon Nanofiber Webs

The influences of various carbonization temperatures on electrical resistivity and morphologies of polyacrylonitrile (PAN)-based nanofiber webs were studied. The diameter size distribution and morphologies of the nanofiber webs were observed by a scanning electron microscope. The electrical resistivity behaviors of the webs were evaluated by a volume resistivity tester. From the results, the volume resistivity of the carbon webs was ranged from <TEX>$5.1{\times}10^{-1}\;{\Omega}{\cdot}cm$</TEX> to <TEX>$3.0{\times}10^{-2}\;{\Omega}{\cdot}cm$</TEX>, and the average diameter of the fiber webs was varied in the range of 310 to 160 nm with increasing the carbonization temperature. These results could be explained that the graphitic region of carbon webs was formed after carbonization at high temperatures. And the amorphous structure of polymeric fiber webs was significantly changed to the graphitic crystalline, resulting in shrinking the size of fiber diameters.

Preparation and Characterization of Activated Carbon Nanofiber Webs Containing Multiwalled Carbon Nanotubes by Electrospinning

Electrochemical double layer capacitors (EDLCs) are promising high power energy sources for many different applications where high power density, high cycle efficiency and long cycle life are needed. However, because the energy density of EDLCs is small compared to that of rechargeable batteries one needs to increase the capacitance of EDLCs. The nanofiber diameters range from 50 nm to 400 nm, depending on the concentration of polymer solution types, tip-to-collector distance, applied voltage, and viscosity of the solution. The main advantage of the electrospinning process is that it is a simple means to prepare continuous fibers with unusually large surface to volume ratios and pore structure surfaces. So, feature of nanofiber webs are the high specific surface area developed by creating pores on the nanofiber surface. In this work, the multiwalled carbon nanotubes embedded polyacrylonitrile solutions in N,N-dimethylformamide (DMF) were electrospun to be webs consisting of 350 nm ultrafine nanofibers, which were used to produce a series of activated carbon nanofibers with developed mesoporosity and high electrical conductivity through stabilization, carbonization-activation processes.

Fabrication of Electrospinning‐Derived Carbon Nanofiber Webs for the Anode Material of Lithium‐Ion Secondary Batteries

AbstractA carbon nanofiber‐based electrode, exhibiting a large accessible surface area (derived from the nanometer‐sized fiber diameter), high carbon purity (without binder), relatively high electrical conductivity, structural integrity, thin web macromorphology, a large reversible capacity (ca. 450 mA h g–1), and a relatively linearly inclined voltage profile, is fabricated by nanofiber formation via electrospinning of a polymer solution and its subsequent thermal treatment. It is envisaged that these characteristics of this novel carbon material will make it an ideal candidate for the anode material of high‐power lithium‐ion batteries (where a high current is critically needed), owing to the highly reduced lithium‐ion diffusion path within the active material.

Effects of iron catalyst on the formation of crystalline domain during carbonization of electrospun acrylic nanofiber

To investigate the effects of introducing the iron compound on the carbonization behavior polyacrylonitile (PAN)-based electrospun nanofibers were carbonized with or without iron(III) acetylacetonate (AAI) over the temperature range of 900–1500 °C in nitrogen atmosphere. The morphological characteristics of the carbon nanofibers were investigated using X-ray diffractometer (XRD), Raman spectroscopy, field emission scanning electron microscopy, and transmission electron microscopy. The electrical conductivity of the carbon nanofiber web was measured by four-point probe method. The iron catalyst had a profound effect on the crystal structure of the carbonized nanofiber. In the presence of AAI the nanofibers carbonized at 1300 °C developed graphite structure, which could be obtained at the temperature higher than 2000 °C in the absence of the catalyst. The in-plane size of the graphite crystals ( L a) was measured to be about 6.5 nm by Raman spectroscopy and the (0 0 2) spacing by XRD was 0.341 nm.