Influence of processing on surface morphology and specific surface area for the nickel foam made by electrodeposition

Purpose With the nickel foam made by the technique of electrodeposition on polymer foam, the purpose of this paper is to investigate the influence of several deferent processes on the surface morphology and the specific surface area of this porous product. Design/methodology/approach The surface morphologies of the nickel foam were examined by SEM. The specific surface area of the porous product was measured by gas (N2) permeability method and also calculated by the reported formula. Findings The nickel foam from sintering in NH3 decomposition atmosphere at 850°C will achieve the same specific surface area as that at 980°C, whether this porous structure after electrodeposition comes through direct sintering in NH3 decomposition atmosphere, or through burning in air at 600°C for 4 min beforehand then the same reductive sintering. Originality/value There have been some studies on the preparation and application of nickel foam, but few works focus on the processing influence on the specific surface of this porous product. The present work provides the investigations on the difference of the product made under different producing conditions, and the influence of several deferent processes on the specific surface area of the product.

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Effects of Hydraulic Gradient and Clay Type on Permeability of Clay Mineral Materials

Minerals ◽

10.3390/min10121064 ◽

2020 ◽

Vol 10 (12) ◽

pp. 1064

Author(s):

Masanori Kohno

Keyword(s):

Hydraulic Conductivity ◽

Specific Surface ◽

Surface Area ◽

Clay Mineral ◽

Specific Surface Area ◽

Hydraulic Gradient ◽

Consistency Index ◽

Hydrogen Energy ◽

The Difference ◽

Mineral Type

Considering the relevance of clay mineral-bearing geomaterials in landslide/mass movement hazard assessment, various engineering projects for resource development, and stability evaluation of underground space utilization, it is important to understand the permeability of these clay mineral-based geomaterials. However, only a few quantitative data have been reported to date regarding the effects of the clay mineral type and hydraulic gradient on the permeability of clay mineral materials. This study was conducted to investigate the permeability of clay mineral materials based on the clay mineral type, under different hydraulic gradient conditions, through a constant-pressure permeability test. Comparative tests have revealed that the difference in the types of clay mineral influences the swelling pressure and hydraulic conductivity. In addition, it has been found that the difference in water pressure (hydraulic gradient) affects the hydraulic conductivity of clay mineral materials. The hydraulic conductivity has been found to be closely associated with the specific surface area of the clay mineral material. Furthermore, the hydraulic conductivity value measured is almost consistent with the value calculated theoretically using the Kozeny–Carman equation. Moreover, the hydraulic conductivity is also found to be closely associated with the hydrogen energy, calculated from the consistency index of clay. This result suggests that the hydraulic conductivity of clay mineral materials can be estimated based on the specific surface area and void ratio, or consistency index of clay.

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Modified polyacrylonitrile-based activated carbon fibers applied in supercapacitor

Pigment & Resin Technology ◽

10.1108/prt-03-2015-0029 ◽

2016 ◽

Vol 45 (3) ◽

pp. 164-171 ◽

Cited By ~ 3

Author(s):

Linjie Su ◽

Bohong Li ◽

Dongyu Zhao ◽

Chuanli Qin ◽

Zheng Jin

Keyword(s):

Activated Carbon ◽

Specific Surface ◽

Specific Capacitance ◽

Surface Area ◽

Specific Surface Area ◽

Carbon Fibers ◽

Electrode Material ◽

High Specific Capacitance ◽

Activated Carbon Fibers ◽

Content Type

Purpose The purpose of this paper is to prepare a new modified activated carbon fibers (ACFs) of high specific capacitance used for electrode material of supercapacitor. Design/methodology/approach In this study, the specific capacitance of ACF was significantly increased by using the phenolic resin microspheres and melamine as modifiers to prepare modified PAN-based activated carbon fibers (MACFs) via electrospinning, pre-oxidation and carbonization. The symmetrical supercapacitor (using MACF as electrode) and hybrid supercapacitor (using MACF and activated carbon as electrodes) were tested in term of electrochemical properties by cyclic voltammetry, AC impedance and cycle stability test. Findings It was found that the specific capacitance value of the modified fibers were increased to 167 Fg-1 by adding modifiers (i.e. 20 wt.% microspheres and 15 wt.% melamine) compared to that of unmodified fibers (86.17 Fg-1). Specific capacitance of modified electrode material had little degradation over 10,000 cycles. This result can be attributed to that the modifiers embedded into the fibers changed the original morphology and enhanced the specific surface area of the fibers. Originality/value The modified ACFs in our study had high specific surface area and significantly high specific capacitance, which can be applied as efficient and environmental absorbent, and advanced electrode material of supercapacitor.

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Effects of Carbonation on the Specific Surface BET of Cement Mortar Measured by Two Different Methods: Nitrogen Adsorption and Water Adsorption

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.931-932.421 ◽

2014 ◽

Vol 931-932 ◽

pp. 421-425 ◽

Cited By ~ 2

Author(s):

Son Tung Pham ◽

William Prince

Keyword(s):

Specific Surface ◽

Surface Area ◽

Specific Surface Area ◽

Water Adsorption ◽

Cement Mortar ◽

Nitrogen Adsorption ◽

Accelerated Carbonation ◽

Molecular Sizes ◽

The Difference ◽

Adsorption Desorption

The objective of this work was to examine the microstructural changes caused by the carbonation of normal mortar. Samples were prepared and subjected to accelerated carbonation at 20°C, 65% relative humidity and 20% CO2concentration. The evolutions of the pore size distribution and the specific surface area during carbonation were calculated from the adsorption - desorption isotherms of water vapour and nitrogen. Conflicts observed in the results showed that the porous domains explored by these two methods are not the same due to the difference in molecular sizes of nitrogen and water. These two techniques therefore help to complementarily evaluate the effects of carbonation. The study also helped to explain why results in the literature diverge greatly on the influence of carbonation on specific surface area.

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Effect of the electrolysis regime on the structural characteristics of honeycomb-like electrodes

Macedonian Journal of Chemistry and Chemical Engineering ◽

10.20450/mjcce.2013.112 ◽

2013 ◽

Vol 32 (1) ◽

pp. 79

Author(s):

Nebojsa D. Nikolic ◽

Goran Branković ◽

Miomir G. Pavlović

Keyword(s):

Surface Morphology ◽

Specific Surface ◽

Surface Area ◽

Specific Surface Area ◽

Structural Characteristics ◽

Hole Size ◽

Porous Structures ◽

Wall Width ◽

Copper Electrodes ◽

Hydrogen Bubbles

The effect of different current regimes of electrolysis on the micro- and nanostructural characteristics of open porous structures was examined by the analysis of honeycomb-like copper electrodes obtained by constant galvanostatic (DC) electrodeposition and by regimes of pulsating (PC) and reversing (RC) current. An increase in the number of holes formed by detached hydrogen bubbles, the decrease in wall width between holes and changes in surface morphology around holes from cauliflower-like agglomerates of copper grains to dendrites were observed in the following order: the DC, PC and RC regime. The hole size formed in the RC regime was smaller than the hole size formed in the DC and PC regimes. Analysis of the obtained structural characteristics showed that the specific surface area of the honeycomb-like electrodes was increased by the application of the PC and RC regimes in relation to the DC regime.

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Comparison of the Biological and Chemical Synthesis of Schwertmannite at a Consistent Fe2+ Oxidation Efficiency and the Effect of Extracellular Polymeric Substances of Acidithiobacillus ferrooxidans on Biomineralization

Materials ◽

10.3390/ma11091739 ◽

2018 ◽

Vol 11 (9) ◽

pp. 1739 ◽

Cited By ~ 6

Author(s):

Yongwei Song ◽

Yelin Liu ◽

Heru Wang

Keyword(s):

Specific Surface ◽

Surface Area ◽

Specific Surface Area ◽

Acidithiobacillus Ferrooxidans ◽

Extracellular Polymeric Substances ◽

Shell Shape ◽

X Ray ◽

Removal Capacity ◽

The Difference ◽

Oxidation Efficiency

Schwertmannite is an environmental mineral material that can promote the natural passivation of heavy metal elements, thereby reducing environmental pollution from toxic elements. However, the fundamental reason for the difference between the chemically (H2O2-FeSO4) and biologically (Acidithiobacillus ferrooxidans-FeSO4) synthesized schwertmannite is still unclear. In this study, X-ray diffraction, scanning electron microscopy, the Brunauer–Emmett–Teller method, and X-ray fluorescence spectrometry were used to compare the structure, specific surface area, and elemental composition of schwertmannite synthesized by biological and chemical methods. The removal capacity of As(III) by the two kinds of schwertmannite and the effects of extracellular polymeric substances (EPS) on biogenetic schwertmannite were also investigated. At a consistent Fe2+ oxidation efficiency, the chemical method synthesized more schwertmannite than the biological method over a 60-h period. The biosynthesized schwertmannite had a “chestnut shell” shape, with a larger particle size and specific surface than the chemically synthesized schwertmannite, which was relatively smooth. The saturated adsorption capacities of the biologically and chemically synthesized schwertmannite were 117.0 and 87.0 mg·g−1, respectively. After exfoliation of the EPS from A. ferrooxidans, the biosynthesized schwertmannite displayed a “wool ball” shape, with rough particle surfaces, many microporous structures, and a larger specific surface area. The schwertmannite yield also increased by about 45% compared with that before exfoliation, suggesting that the secretion of EPS by A. ferrooxidans can inhibit the formation of schwertmannite.

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Hydrothermal Synthesis of Co-Doped NiSe2 Nanowire for High-Performance Asymmetric Supercapacitors

Materials ◽

10.3390/ma11081468 ◽

2018 ◽

Vol 11 (8) ◽

pp. 1468 ◽

Cited By ~ 7

Author(s):

Yun Gu ◽

Le-Qing Fan ◽

Jian-Ling Huang ◽

Cheng-Long Geng ◽

Jian-Ming Lin ◽

...

Keyword(s):

Electron Microscopy ◽

Energy Density ◽

Specific Surface ◽

Surface Area ◽

Specific Surface Area ◽

Electrode Materials ◽

Nickel Foam ◽

High Energy ◽

High Energy Density ◽

Asymmetric Supercapacitor

Co@NiSe2 electrode materials were synthesized via a simple hydrothermal method by using nickel foam in situ as the backbone and subsequently characterized by scanning electron microscopy, transmission electron microscopy, energy-dispersive X-ray spectroscopy, and a specific surface area analyzer. Results show that the Co@NiSe2 electrode exhibits a nanowire structure and grows uniformly on the nickel foam base. These features make the electrode show a relatively high specific surface area and electrical conductivity, and thus exhibit excellent electrochemical performance. The obtained electrode has a high specific capacitance of 3167.6 F·g−1 at a current density of 1 A·g−1. To enlarge the potential window and increase the energy density, an asymmetric supercapacitor was assembled by using a Co@NiSe2 electrode and activated carbon acting as positive and negative electrodes, respectively. The prepared asymmetrical supercapacitor functions stably under the potential window of 0–1.6 V. The asymmetric supercapacitor can deliver a high energy density of 50.0 Wh·kg−1 at a power density of 779.0 W·kg−1. Moreover, the prepared asymmetric supercapacitor exhibits a good rate performance and cycle stability.

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Bead chain structure RFC/ACF by electrospinning for supercapacitors

Pigment & Resin Technology ◽

10.1108/prt-08-2018-0074 ◽

2019 ◽

Vol 48 (5) ◽

pp. 439-448

Author(s):

Lei Guo ◽

Lien Zhu ◽

Lei Ma ◽

Jian Zhang ◽

QiuYu Meng ◽

...

Keyword(s):

Composite Material ◽

Specific Surface ◽

Specific Capacitance ◽

Surface Area ◽

Specific Surface Area ◽

Carbon Fibers ◽

High Specific Capacitance ◽

Chain Structure ◽

Cycle Stability ◽

Content Type

Purpose The purpose of this paper is to prepare a spherical modifier-modified activated carbon fiber of high specific capacitance intended for electrode materials of supercapacitor. Design/methodology/approach In this study, phenolic-based microspheres are taken as modifiers to prepare PAN-based fiber composites by electrospinning, pre-oxidation and carbonization. Pearl-chain structures appear in RFC/ACF composites, and pure polyacrylonitrile fibers show a dense network. The shape and cross-linking degree are large. After the addition of the phenolic-based microspheres, the composite material exhibits a layered pearlite chain structure with a large porosity, and the RFC/ACF composite material is derived because of the existence of a large number of bead chain structures in the composite material. The density increases, the volume declines and the mass after being assembled into a supercapacitor as a positive electrode material decreases. The specific surface area of RFC/ACF composites is increased as compared to pure fibers. The increase in specific surface area could facilitate the diffusion of electrolyte ions in the material. Owing to the large number of bead chains, plenty of pore channels are provided for the diffusion of electrolyte ions, which is conducive to enhancing the electrochemical performance of the composite and improving the RFC/ACF composite and the specific capacitance of the material. The methods of electrochemical testing on symmetric supercapacitors (as positive electrodes) are three-electrode cyclic voltammetry, alternating current impedance and cycle stability. Findings The specific capacitance value of the composite material was found to be 389.2 F/g, and the specific capacitance of the electrode operating at a higher current density of 20 mA/cm2 was 11.87 F/g (the amount of the microsphere modifier added was 0.3 g). Using this material as a positive electrode to assemble into asymmetrical supercapacitor, after 2,000 cycles, the specific capacitance retention rate was 87.46 per cent, indicating excellent cycle stability performance. This result can be attributed to the fact that the modifier embedded in the fiber changes the porosity between the fibers, while improving the utilization of the carbon fibers and making it easier for electrolyte ions to enter the interior of the composites, thereby increasing the capacitance of the composites. Originality/value The modified PAN-based activated carbon fibers in the study had high specific surface area and significantly high specific capacitance, which makes it applicable as an efficient and environment-friendly absorbent, as well as an advanced electrode material for supercapacitor.

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Effect of Morphology of ZnCo2O4 Nanostructures on Electrochemical Performance

NANO ◽

10.1142/s1793292016500892 ◽

2016 ◽

Vol 11 (08) ◽

pp. 1650089 ◽

Cited By ~ 5

Author(s):

J. Y. Dong ◽

N. Zhang ◽

S. Y. Lin ◽

T. T. Chen ◽

M. Y. Zhang ◽

...

Keyword(s):

Electrochemical Performance ◽

Specific Surface ◽

Electrochemical Properties ◽

Specific Capacitance ◽

Hydrothermal Method ◽

Surface Area ◽

Specific Surface Area ◽

Nickel Foam ◽

High Specific Surface Area ◽

Active Materials

The ZnCo2O4 nanorods and nanosheets were grown on nickel foam by a facile and effective hydrothermal method, respectively. The effect of the morphologies of the nanostructures on electrochemical performance was investigated. Importantly, ZnCo2O4 nanorod electrodes with a high specific surface area exhibited a higher specific capacitance of 2457.4 F g[Formula: see text] at 2 A g[Formula: see text] and remarkable cycling stability with capacitance retention of 97.7% after 1000 cycles, which are superior to those of ZnCo2O4 nanosheet electrodes. Such a result is well explained. The investigation on the electrochemical properties of these two nanostructures as electrodes confirmed that the morphology of active materials has an important impact on electrochemical properties.

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The Study of Specific Surface Area from Carbonat Rock Using Micro Computed Tomography (µ-CT)

Proceeding International Conference on Science and Engineering ◽

10.14421/icse.v1.278 ◽

2017 ◽

Vol 1 ◽

pp. 111-113

Author(s):

Mahendra Risky Habibi ◽

Thaqibul Fikri Niyartama

Keyword(s):

Computed Tomography ◽

Specific Surface ◽

Surface Area ◽

Specific Surface Area ◽

Calculation Result ◽

Carbonate Rocks ◽

Programming Algorithm ◽

Micro Ct ◽

Micro Computed Tomography ◽

The Difference

Carbonate rocks have been scanned and reconstructed in order to get the value of specific surface area. We get it from the reservoir at a depth of 1000 metres in South Sumatra. Skyscan Micro-CT 1173 is used for throwing and thresholding images using Global Otshu to characterize rocks. Our calculation result shows that the value of specific surface area of carbonate rocks show results 100 to 10-2 using the programming Algorithm Fuzzy C-Mean. The difference in values far enough that it can be assumed that the carbonate rocks have a heterogeneous surface area. In addition, histogram model shows the similarity of the sample. The macro sample has the same characteristics as the micro sample.

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Electrospun flexible lignin/polyacrylonitrile-based carbon nanofiber and its application in electrode materials for supercapacitors

Textile Research Journal ◽

10.1177/00405175211037191 ◽

2021 ◽

pp. 004051752110371

Author(s):

Hong Wu ◽

Chengkun Liu ◽

Zhiwei Jiang ◽

Zhi Yang ◽

Xue Mao ◽

...

Keyword(s):

Specific Surface ◽

Surface Area ◽

Specific Surface Area ◽

Electrode Materials ◽

Carbon Nanofiber ◽

Electrochemical Impedance ◽

Nickel Foam ◽

Average Diameter ◽

Raw Material ◽

Equivalent Series Resistance

In this study, a lignin/polyacrylonitrile (PAN) composite nanofiber membrane is prepared by electrospinning and used as the precursor to prepare flexible carbon nanofibers (CNFs) through pre-oxidation and carbonization. The micromorphology, crystal structure, pore size distribution and specific surface area of the CNFs are characterized by field emission scanning electron microscopy, X-ray diffraction, Raman spectroscopy and specific surface adsorption analysis, respectively. The electrochemical properties of the CNF membrane are also investigated by cyclic voltammetry, galvanostatic charge–discharge and electrochemical impedance spectroscopy due to its potential application in binder-free electrode materials for supercapacitors. We successfully prepared flexible CNFs with an average diameter of about 539 nm and a specific surface area of 1053.78 m2/g when the mass ratio of lignin to PAN was 9:1 in a solution concentration of 28 wt%. The CNFs are loaded onto nickel foam to prepare the electrode materials for supercapacitors without a binder. When the current density is 0.5 A/g, the specific capacitance could be up to 201.27 F/g and the equivalent series resistance is only 0.57 Ω, which shows an excellent electrochemical performance. This study not only provides a theoretical basis for the high-value utilization of lignin and the preparation of flexible lignin/PAN-based CNFs, but also provides a new type of environmentally friendly raw material for the electrodes of supercapacitors and could be helpful to alleviate the energy crisis and environmental pollution.

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