Amphiphilic Carbonaceous Material Research Articles

Study on the structure and electrochemical performances of amphiphilic carbonaceous material-based porous carbon electrode materials

Amphiphilic carbonaceous material was dissolved in the sodium acetate aqueous solution and the resulting liquid was used to synthesize the hierarchical porous carbons (HPCs) in which sodium acetate acted as chemical activation agent. Benefiting from the optimum balance between unique hierarchical porous network and high specific surface area (1389 m2 g−1) the optimal sample presented a remarkable capacity (221F g−1 at 0.05 A g−1) and outstanding cycling stability (only 4.5% loss of the initial capacitance after 10,000 cycles) in 6 mol L-1 KOH. The results provides the potential of developing amphiphilic carbonaceous material-based carbon electrode materials for high-performance supercapacitors.

Lignin‐Derived Hard Carbon Microspheres Synthesized via Emulsion‐Solvent Evaporation as Anode for Sodium Storage

Lignin‐derived hard carbon microspheres with different amphiphilic carbonaceous material (ACM) contents are synthesized through a facile emulsion‐solvent evaporation process and subsequent thermal treatment. The influence of lignin/ACM mass ratio on morphology, microstructure, thermal stability, and electrochemical properties of carbon microspheres is studied in detail. Combined with Fourier‐transform infrared spectroscopy (FT‐IR) and thermogravimetric analysis, the interaction between lignin and ACM leads to enhanced thermal stability with a carbonization yield of 50.6%. Meanwhile, X‐ray diffraction (XRD) results indicate enlarged graphite‐like crystallite dimensions, Laand Lc,which contribute to electric conductivity. Due to ACM addition, the electrochemical performance is improved. When the mass ratio of lignin/ACM is 3:1, the sample exhibits a well‐balanced performance. The reversible capacity is 296.5 mAh g−1 with a high initial Coulombic efficiency of 82.0%. In the cycling test, the sample retains a capacity of 276.8 mAh g−1 after 100 cycles, corresponding to a capacity retention ratio of 90.8%.

Synthesis of homogeneously dispersed manganese oxide/ carbon 3D nanocomposites and their electrochemical performance in lithium-ion batteries

A MnOx/carbon nanocomposite was synthesized from a novel pitch-derived amphiphilic carbonaceous material (ACM). Characterization of this nanocomposite reveals that the nanosized manganese oxide particles are uniformly embedded in a porous carbon framework. When evaluated as the anode for lithium-ion batteries (LIBs), the structural features of the nanocomposite lead to an enhanced electrochemical performance with a high reversible capacity of ~ 900 mAh g−1 at 50 mA g−1, excellent cyclic stability (620mAh g−1at 300 mA g−1 after 500 cycles) and good rate performance (~ 320mAh g−1 at 4 A g−1). The desirable electrochemical properties of the nanocomposite combined with its simple hybridization method make the prepared composite a promising electrode material for high-performance LIBs.

Enhanced pervaporative performance of hybrid membrane by incorporating amphiphilic carbonaceous material

Amphiphilic carbonaceous material (ACM) was blended with sodium alginate (SA) and then deposited onto the polyacrylonitrile (PAN) porous support layer to fabricate SA-ACM/PAN hybrid membranes. As a two-dimensional material, ACM provided anisotropy, horizontal stacking orientation and high aspect ratio. The abundant oxygen-containing functional groups (–NO2, –SO3H, –OH, –COOH and epoxy group) on the edge of ACM (proved by X-ray photoelectron spectroscopy and scanning electron microscope with energy dispersive X-ray (EDX) spectrometer) offered the hydrophilic region, while the unoxidized part on the surface of ACM offered hydrophobic region. The hydrophilic region on ACM could preferentially adsorb water molecules and then facilitate water molecules entering the transport channel due to the hydrogen bond, while the hydrophobic region could realize the fast diffusion of water molecules. The small nanosheet size (200–400nm, observed by atomic force microscopy) could interfere the arrangement of polymer chains more efficiently. The hybrid membranes exhibited the optimal permeation flux of 1778g/m2h and separation factor of 1816 for ethanol dehydration under 76°C and 10wt% feed water concentration, which is much higher than that of SA membrane (increased by 139% and 306%, respectively).

MgO-templated mesoporous carbons using a pitch-based thermosetting carbon precursor

MgO-templated mesoporous carbons from pitch-based thermosetting amphiphilic carbonaceous material possess yields of 17% and outstanding electrochemical performances.

Enhanced kinetic behaviors of LiMn0.5Fe0.5PO4/C cathode material by Fe substitution and carbon coating

The LiMn0.5Fe0.5PO4/C nanocrystallites with a uniform size (∼50 nm) are successfully prepared by employing a facile solvothermal method at 180 °C. Amphiphilic carbonaceous material (ACM) is chosen as the carbon precursor and forms a homogeneous carbon layer covering the LiMn0.5Fe0.5PO4 particles. The as-prepared LiMn0.5Fe0.5PO4/C sample, with a high Brunauer-Emmett-Teller (BET) surface area of 69.3 m2 g−1, is used as the cathode material for lithium-ion batteries (LIBs) and delivers a reversible capacity of 158 mAh g−1 at 0.05 C. It shows remarkable rate capability with discharge capacities of 130 mAh g−1 at 1 C, 105 mAh g−1 at 10 C and 99 mAh g−1 at 30 C. Meanwhile, the material maintains 121 mAh g−1 at 1 C after 150 cycles with 93 % capacity retention. The kinetic behaviors of LiMn0.5Fe0.5PO4/C sample are investigated by high throughout cyclic voltammetry. The small particle size, partial Fe substitution, and homogeneous carbon coating make a synergetic effect on enhancing the sample’s electrochemical properties.

Synergetic Fe substitution and carbon connection in LiMn1−xFexPO4/C cathode materials for enhanced electrochemical performances

To enhance the rate and cyclic performances of LiMnPO4 cathode material for lithium-ion batteries, Mn is partially substituted with Fe, and LiMn1−xFexPO4 (x=0.2, 0.3, 0.4, 0.5) solid solutions are synthesized and investigated. Amphiphilic carbonaceous material (ACM) forms well carbon coating and connects the LiMn1−xFexPO4 crystallites by a three-dimensional (3D) carbon network. The synergetic Fe substitution and carbon connection obviously improve the samples’ rate capacities and cyclic stability. The optimized LiMn0.6Fe0.4PO4/C sample delivers discharge capacities of 160mAhg−1 at 0.05C, 148mAhg−1 at 1C, and 115mAhg−1 at 20C. All samples have well capacity retention (>92%) after 50 charge/discharge cycles at 1C. The enhanced electrochemical properties are mainly attributed to the improvement of Li ion and electron transport in the LiMn1−xFexPO4/C samples, respectively mainly resulting from their modified crystal structures caused by Fe substitution and the 3D carbon coating/connection originating from ACM carbonization. LiMn1−xFexPO4 materials exhibit two discharge plateaus at ∼4.0 and ∼3.5V (vs. Li+/Li), whose heights respectively reflect the redox potentials of Mn3+/Mn2+ and Fe3+/Fe2+ couples. The plateaus’ lengths correspond to the Mn/Fe ratio in LiMn1−xFexPO4 and are affected by the kinetic behavior of samples. Though the ∼4.0V plateau shrinks with increasing discharge rate, the ∼3.5V plateau may slightly elongate. Moreover, the Fe substituted in the partial Mn sites could significantly improve the Li ion diffusion, thus enhance the kinetic behaviors of LiMn1−xFexPO4.

Amphiphilic carbonaceous material-based hierarchical porous carbon aerogels for supercapacitors

Novel hierarchical porous carbon aerogels (PCAs) derived from amphiphilic carbonaceous material (ACM) have been mass-prepared via a facile solvent exchange induced self-assembly process and subsequent carbonization and KOH activation. The resulting products are stacked up by highly interconnected carbon nanoparticles with a certain amount of micropores and mesopores, which aggregate to build a three-dimensional macroporous architecture. The hierarchical porous structure facilitates fast ion transportation inside the electrode simultaneously preserving efficient ion surface electrochemical reactions. Capacitive and rate performances were evaluated by fabricating symmetric capacitors with both aqueous and organic electrolytes. The PCA-0.5 and PCA-1.0 electrodes exhibit superior specific capacitances of 261.2 and 227.9 F g−1 at a current density of 0.05 A g−1 in 6 M KOH electrolyte, and still remain 145.5 and 175.4 F g−1 as the current density increases to 100 A g−1, respectively. Remarkably, the PCA-0.5 and PCA-1.0 electrodes show stable cycle durability with a slight capacitance loss of 8.2 and 11.2 % after 5000 cycles at 1 A g−1, respectively. Furthermore, in organic electrolyte system, the PCA-1.0 electrode manifests an outstanding capacitance of 155.4 F g−1 at a current density of 0.05 A g−1. The encouraging results demonstrate that PCAs are a sort of promising and competitive supercapacitors electrode materials.

Effects of Amphiphilic Carbonaceous Nanomaterial on the Synthesis of MnO2 and Its Energy Storage Capability as an Electrode Material for Pseudocapacitors

An amphiphilic carbonaceous material (called CP-A5) derived from coal tar pitch has been introduced to synthesize a hollow MnO2/CP-A5 hybrid on the meso- or microscale in a poly(ethylene glycol) 400–water mixture using a self-template method. In the presence of CP-A5, the MnCO3 precursors change from cubes of approximately 450 nm to spheres of approximately 300 nm, and their basic building blocks vary from two-dimensional nanosheets to nanoflakes. The derived two types of hollow MnO2 preserve the morphologies of their own precursors well and inherit the basic building blocks. The electrochemical data indicate that MnO2/CP-A5 hollow spheres exhibit not only higher specific capacitance and lower resistance, including the intrinsic resistance of the electrode, Faradaic reaction resistance, and ion-diffusion/-transport resistance, but also better electrochemical stability than MnO2 hollow cubes because of their reduced particle size, induced morphology, and modified electrode/electrolyte interface.

Amphiphilic carbonaceous material-intervened solvothermal synthesis of LiFePO4

LiFePO4 samples with preferred facets on the ac plane were prepared by the solvothermal method with or without well-dispersed amphiphilic carbonaceous material (ACM). The effects of ACM on the particle morphology, crystal orientation and electrochemical reactivity of the prepared LiFePO4 nanoparticles were investigated in detail. ACM serves a dual purpose. One purpose is facilitating the plate-like morphologies of LiFePO4 nanoparticles parallel to the bPnma axis by decreasing the surface energy of (010) facets of newly created LiFePO4 nuclei. The other purpose is suppressing crystal growth along the [010] direction by adhering onto the (010) surface of LiFePO4 nanoplates. Furthermore, ACM coating was performed and optimized using a carbon coating precursor. The electrochemical properties of the prepared LiFePO4 particles were characterized by cyclic voltammetry (CV) and galvanostatic charge–discharge cycling tests. After the optimized coating of ACM, the ACM-intervened LiFePO4 composite was observed to deliver discharge capacities of 151.3 mAh g−1 at 1C and 132.2 mAh g−1 at 10C. Even after 1000 cycles at a high rate of 10C, the LiFePO4 cathode could maintain 80% of its initial capacity.

Effects of Pre-Carbonization on Structure and Electrochemical Performances of Amphiphilic Carbonaceous Material-Based Activated Carbons

Activated carbons to be used as electrode in electrochemical double-layer capacitors were fabricated using amphiphilic carbonaceous material (ACM) as precursor. To study the significance of functional groups and microcrystalline of the precursor in preparing AC, we applied pre-carbonization upon the ACM under different conditions to control these two parameters in this paper. FTIR and XPS spectra showed functional groups on the precursors decreased as the increase of pre-carbonization temperature. After carbonization at 800 °C, the growth of graphitic microcrystallites was noticeable. Porous structure parameters of final ACs inferred that the functional groups on the precursors have a more significant effect than microcrystalline size on formation of mesopores during activation process not only for its role as active sites but also the homogeneous activation profited from the solubility of samples in alkaline solutions. The sample AC0 with almost half mesopores showed the best electrochemical behavior with a specific gravimetric capacitance of 255 F/g at current density of 1000mA/g and kept rectangular shape cyclic voltammetry curve even at scan rate high as 400 mV/s.

Carbon coating of Li4Ti5O12 using amphiphilic carbonaceous material for improvement of lithium-ion battery performance

Carbon coating of fine particles of Li4Ti5O12 synthesized under hydrothermal condition is carried out by amphiphilic carbonaceous material (ACM) in aqueous solution, followed by carbonization at 800°C for 2h. The particles prepared are comprised of highly-crystalline spinel-type Li4Ti5O12 with the size in the range of 100–400nm without any agglomeration, of which surface is uniformly covered by a thin carbon layer. Their electrochemical performance as an anode in lithium-ion batteries is evaluated. The initial discharge capacity of carbon-coated Li4Ti5O12 at 20C rate is 137mAhg−1 and remains as high as 125mAhg−1 after 100 cycles (91% retention), exhibiting good rate and cyclic performance. Carbon coating by using ACM as carbon precursor gives the Li4Ti5O12 particles an enhanced performance as an anode in lithium-ion batteries, owing to the improvement in electrical conductivity, polarization and ability of dispersion. This non-organic coating process may present a new economic, facile, and green pathway for the preparation of carbon-coated Li4Ti5O12 as a high power anode material in lithium-ion batteries.

A facile method to prepare carbon aerogels from amphiphilic carbon material

Using green needle coke (GNC) based amphiphilic carbonaceous material (ACM) as the only raw material, carbon aerogels was successfully synthesized via a very simple method at room temperature, followed by drying at ambient pressure and carbonization in an inert atmosphere. The resulting product was piled up by highly connected nano-particles with diameters of 30–50nm, which constructed a 3-D architecture also providing certain mesopores and macropores. After being carbonized at 500°C, the diameter of nano-particles shrank to about 25nm and still maintain some connective ligament parts. Meanwhile, N2 sorption analysis showed that the SBET of CAs-500 is 292m2/g and had a wide pore size distribution from micropores to macropores. After further activation, such special dimensional structure guaranteed the carbon aerogel a potential electrode material for electrochemical capacitor.

Preparation of mesoporous carbons from amphiphilic carbonaceous material for high-performance electric double-layer capacitors

Amphiphilic carbonaceous material (ACM), with nanoscale dispersion in alkaline aqueous solutions, is synthesized from green needle coke. As a special precursor with small particle size, plenty of functional groups and widened d 002 simultaneously, ACM guarantees subsequent ACM-based activated carbons (AACs) with high specific surface area over 3000 m 2 g −1 as well as well-developed mesoporous structure after KOH activation. Such pore properties enable AACs’ high performances as electrode materials for electric double-layer capacitors (EDLCs). In particular, surface area up to 3347 m 2 g −1 together with notable mesopore proportion (26.9%) gives sample AAC814 outstanding EDLC behaviors during a series of electrochemical tests including galvanostatic charge/discharge, CV and electrochemical impedance spectroscopy. The electrode gets satisfactory gravimetric and volumetric specific capacitance at the current density of 50 mA g −1, up to 348 F g −1 and 162 F cm −3, respectively. Furthermore, for the mesoporosity, there is only a slight capacitance reduction for AAC814 as the current density reaches 1000 mA g −1, indicating its good rate performance. It is all the ACM's unique characteristics that make AACs a sort of competitive EDLC electrode materials, both in terms of specific capacitance and rate capability.

Amphiphilic carbonaceous material modified graphite as anode material for lithium-ion batteries

Artificial graphite powder was coated by amphiphilic carbonaceous material (ACM) in aqueous solutions. SEM and XRD results show that the surface defects and edge sites of original graphite are uniformly covered by the ACM coating layer after modification. The overall characteristics of graphite, however, are not severely changed. Electrochemical measurements were then carried out to evaluate the anode performances of samples in lithium-ion batteries. The modified graphite shows an initial efficiency up to 90.6% and discharge capacitance of 366.4mAhg−1. Meanwhile, its capacitance remains as high as 350mAhg−1 after 30cycles charge/discharge tests, evincing good cyclic performance. Compared with conventional methods, the abovementioned non-organic solvent coating presents an economic, facile, and green pathway for graphite mass utilisation as an alternative anode material in lithium-ion batteries.

A novel vesicular carbon synthesized using amphiphilic carbonaceous material and micelle templating approach

A novel carbon with vesicular, hierarchical structure was synthesized via a direct, micelle templating strategy. This vesicular carbon exhibits a wormlike morphology, very thin shells (5–30 nm) and mesopores of 2–4 nm within the shell that are perpendicular to the walls of the carbon vesicles. The structure of this novel vesicular carbon was verified by X-ray diffraction and electron microscopy.

On the Possibility of Surface Modification of an Alumina Support with Amphiphilic Carbonaceous Material

A carbon-coated support has been prepared by the impregnation of commercial alumina with an ammoniacal solution of amphiphilic carbonaceous material. It was established that the method used for the deposition of the carbon coating on the support allowed control of both the layer thickness and the degree of filling of the surface in the low carbon content region. Equations proposed for the approximate determination of the thickness of the deposited carbon layer and of the surface occupied by this layer enabled a tentative prediction to be made of the most desirable parameters for such a system.

Preparation of hollow carbon-microbeads from water-in-oil emulsion using amphiphilic carbonaceous material

Abstract Carbon microbeads were prepared from water-in-oil emulsion using amphiphilic carbonaceous material and urea. With urea as a forming agent with a concentration 1–20 wt.%, hollow carbon-microbeads were obtained, and their particle size ranged between 2 and 15 μm. The true density of the hollow carbon-microbeads was changed, by varying the concentration of urea and the heat-treatment temperature. In particular, a pore size of about 50 A was predominantly produced under a certain condition.

Preparation and characterization of an electrocatalytic electrode using amphiphilic carbonaceous material containing metal compound

Electrocatalytic electrodes were prepared by coating amphiphilic carbonaceous material containing platinum acetylacetonate from N, N-dimethylformamide on a glassy carbon surface. The electrocatalytic activity of the electrodes was evaluated for hydrogen generation in 1 M hydrogen perchloride by means of voltammetry. The current densities for proton reduction increased at the potential of −0.2 V vs Ag/AgCl with increasing concentration of platinum acetylacetonate and with heat-treatment temperature. However, at higher concentrations of platinum acetylacetonate and higher heat-treatment temperatures, the current densities were decreased. These electrocatalytic activities were strongly dependent on states of the coating layer including platinum surface area.

Catalytic property of platinum-dispersed carbon prepared using amphiphilic carbonaceous material

Platinum-dispersed carbon was prepared from amphiphilic carbonaceous material and [Pt(NH 3) 4](OH) 2 using ammonia water. These reaction mixtures gelled and were dried then finally heat-treated. In all the samples, platinum particle diameters varied from a few nanometers to 20 nm in the carbon matrix. The platinum-dispersed carbon that had only been heat-treated did not exhibit any catalytic activity for hydrogenation of cyclohexene. However, activation with CO 2 enhanced the catalytic activity, which depended on the activation time and on the Pt loading.