scholarly journals Structure and Performance of Carbon Aerogel Electrodes

1994 ◽  
Vol 349 ◽  
Author(s):  
R.W. Pekala ◽  
S.T. Mayer ◽  
J.F. Poco ◽  
J.L. Kaschmitier
Keyword(s):  
Large Fraction ◽  
High Surface ◽  
Carbon Aerogel ◽  
High Energy ◽  
Structural Features ◽  
Carbon Aerogels ◽  
Cluster Assembly ◽  
Surface Areas ◽  
And Performance ◽  
Small Clusters

ABSTRACTThe chemistry and physics of small clusters of atoms (1-100 nm) has received considerable attention in recent years because these assemblies often have properties between the molecular and bulk solid-state limits. The different properties can be explained in terms of the large fraction of atoms that are at the surface of a cluster as compared to the interior. Although the synthesis and properties of metal and semiconductor clusters, metallocarbohedrenes, fullerenes, and nanotubes are the subject of extensive investigations, little attention has been paid to cluster-assembled porous materials. This oversight is of particular interest to us since we believe that aerogels are one of the few monolithic materials presently available where the benefits of cluster assembly can be demonstrated. In particular, the unique optical, thermal, acoustic, mechanical, and electrical properties of aerogels are directly related to their nanostructure, which is composed of interconnected particles (3-30 nrm) with small interstitial pores (< 50 nm). This structure leads to extremely high surface areas (400-1100 m2/g) with a large fraction of the atoms covering the surface of the interconnected particles. As a result of these structural features, carbon aerogels are finding applications as electrodes in supercapacitors with high energy and power densities.

scholarly journals Effects of Processing Conditions on the Physical and Electrochemical Properties of Carbon Aerogel Composites

1997 ◽  
Vol 496 ◽  
Author(s):  
T. D. Tran ◽  
D. Lenz ◽  
K. Kinoshita ◽  
M. Droege
Keyword(s):  
Physical Properties ◽  
High Surface ◽  
Carbon Aerogel ◽  
Carbon Aerogels ◽  
Carbon Paper ◽  
Composite Electrodes ◽  
Resorcinol Formaldehyde ◽  
Surface Areas ◽  
Thin Carbon ◽  
Electrochemical Double Layer

ABSTRACTThe carbon aerogel/carbon paper composites have physical properties similar to those of monolithic carbon aerogels but do not require supercritical extraction during fabrication. The resorcinol-formaldehyde based carbon aerogel phase is intertwined between the fibers of a commercial carbon paper. The resulting composites have variable densities (0.4–0.6 g/cc), high surface areas (300–600 m2/g), and controllable pore sizes and pore distribution. The effects of the resorcinol-formaldehyde concentrations (50–70% w/v) and the pyrolysis temperature (600–1050°C) were studied in an attempt to tailor the aerogel microstructure and properties. The composite physical properties and structure were analyzed by transmission electron microscopy and multipoint-BET analyses and related to electrochemical capacitive data in 5M KOH. These thin carbon aerogel/carbon paper composite electrodes are used in experiments with electrochemical double-layer capacitors and capacitive deionization.

Performance Study and Structure Control of Carbon Aerogel

2013 ◽  
Vol 706-708 ◽  
pp. 897-900 ◽  
Author(s):  
Rui He ◽  
Xuan Liu ◽  
Zhen Fa Liu ◽  
Li Hui Zhang
Keyword(s):  
High Surface ◽  
Sol Gel ◽  
Supercritical Drying ◽  
Carbon Aerogel ◽  
Preparation Condition ◽  
Carbon Aerogels ◽  
Performance Study ◽  
Structure Control ◽  
Sol Gel Process ◽  
Nanopore Structure

In this research the fabrication of carbon aerogel is reported. nanopore carbon aerogels were prepared via a sol-gel process with resorcinol and formaldehyde (RF) aerogels,which were cost-effectively manufacture form Rf wet gels by an ambient drying technique instead of conventional supercritical drying. The key of the work is to fabricate carbon aerogels with controllable nanopore structure, which means sharp pore size distribution and extremely high surface area.The influence of preparation condition of carbon aerogels was studied by scanning electron microscope and Micropore Physisorption Analyzer. The BET surface of the carbon aerogels are from 749m2/g to 1156m2/g .The size of the carbon nanoparticles are in the range of 20nm~40nm. The micro-pore volume and bore diameter can be controlled by gelation conditions such as RF mass fraction.

Powdery polymer and carbon aerogels with high surface areas for high-performance solid phase microextraction coatings

Nanoscale ◽  
2017 ◽  
Vol 9 (17) ◽  
pp. 5545-5550 ◽  
Author(s):  
Juan Zheng ◽  
Junlong Huang ◽  
Fei Xu ◽  
Fang Zhu ◽  
Dingcai Wu ◽  
...  
Keyword(s):  
Solid Phase Microextraction ◽  
High Performance ◽  
Solid Phase ◽  
High Surface ◽  
Carbon Aerogels ◽  
Surface Areas

Template-Method Synthesis of High-Surface-Area Monolithic Carbon Aerogels and Their Applications for Hydrogen and Deuterium Adsorption

2017 ◽  
Vol 16 (05n06) ◽  
pp. 1750010 ◽  
Author(s):  
Bowei Chen ◽  
Xiaojun Wang ◽  
Jiayi Zhu ◽  
Yutie Bi ◽  
Xuan Luo ◽  
...  
Keyword(s):  
Adsorption Capacity ◽  
Surface Area ◽  
Hydrogen Adsorption ◽  
High Surface ◽  
High Surface Area ◽  
Carbon Aerogel ◽  
Molar Ratio ◽  
Template Method ◽  
Carbon Aerogels ◽  
Polymer Templates

In this work, novel monolithic carbon aerogels obtained by using a polymer template method were characterized and evaluated for their applications in the hydrogen and deuterium adsorption capacity. The properties (i.e., surface area, pore size distribution, hydrogen and deuterium adsorption capacities, etc.) of the carbon aerogels were affected by the polymer templates. The results showed that the carbon aerogel with the molar ratio of polyacrylic acid (PAA) to zinc chloride (ZnCl2) being 0.75:40 was featured the highest surface area (1806 m2/g) and had the highest hydrogen adsorption capacity. Moreover, the deuterium adsorption capacity of the carbon aerogel was to be further elucidated.

Fabrication of Ultra-Low Density, High Surface Area Carbon Aerogels and their Application in Supercapacitors

2016 ◽  
Vol 852 ◽  
pp. 1349-1355
Author(s):  
Jia Yi Zhu ◽  
Xi Yang ◽  
Zhi Bing Fu ◽  
Chao Yang Wang ◽  
Wei Dong Wu ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Surface Area ◽  
High Surface ◽  
High Surface Area ◽  
Three Dimensional ◽  
Carbon Aerogel ◽  
Carbon Aerogels ◽  
Low Density ◽  
Organic Aerogel ◽  
Cyclic Voltammetry Test

The ultra-low density carbon aerogel, as low as 20 mg/cm3, was fabricated by pyrolysis of the organic aerogel formed by aqueous condensation of resorcinol and formaldehyde. Its surface area was as high as 1783 m2/g and it was used for investigation of electrochemical capacitive behaviours. The ultra-low density carbon aerogel displayed capacitive performance (110 F/g at 0.2 A/g) in 6 M KOH aqueous solution. Additionally, over 98% of the initial capacitance was retained after repeating the cyclic voltammetry test for 1000 cycles. The electrochemical performance might be attributed to the combination of three dimensional “opened” structure and high surface area of the carbon aerogel.

Fabrication of novel powdery carbon aerogels with high surface areas for superior energy storage

2017 ◽  
Vol 7 ◽  
pp. 8-16 ◽  
Author(s):  
Fei Xu ◽  
Jing Xu ◽  
Hongji Xu ◽  
Yuheng Lu ◽  
Hongyu Yang ◽  
...  
Keyword(s):  
Energy Storage ◽  
High Surface ◽  
Carbon Aerogels ◽  
Surface Areas

scholarly journals A Comparison of the Electrochemical Behavior of Carbon Aerogels and Activated Carbon Fiber Cloths

1996 ◽  
Vol 431 ◽  
Author(s):  
T. D. Tran ◽  
C. T. Alviso ◽  
S. S. Hulsey ◽  
J. K. Nielsen ◽  
R. W. Pekala
Keyword(s):  
Activated Carbon ◽  
Carbon Fiber ◽  
Electrochemical Behavior ◽  
High Surface ◽  
High Surface Area ◽  
Activated Carbon Fiber ◽  
Solid Matrix ◽  
Carbon Aerogels ◽  
Surface Areas ◽  
Cell Structures

AbstractThe electrochemical capacitative behavior of carbon aerogels and selected commercial carbon fiber cloths was studied in 5M potassium hydroxide, 3M sulfuric acid, and 0.5M tetraethylammonium tetrafluoroborate/propylene carbonate electrolytes. The resorcinolformaldehyde based carbon aerogels with a range of density (0.2–0.85 g/cc) have open-cell structures with ultrafine pore sizes (∼5–50 nm), high surface area (400–700 m2/g), and a solid matrix composed of interconnected particles or fibers with characteristic diameters of 10 nm. The commercial fiber cloths in the density range 0.2–0.4g/cc have high surface areas (1000–2500 m2/g). The volumetric capacitances of high-density aerogels are shown to be comparable to or exceeding those obtained from activated carbon fibers. The electrochemical behavior of these types of materials in various electrolytes is compared and related to their physical properties.

scholarly journals Hetero-Porous, High-Surface Area Green Carbon Aerogels for the Next-Generation Energy Storage Applications

Nanomaterials ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 653
Author(s):  
Bony Thomas ◽  
Shiyu Geng ◽  
Mohini Sain ◽  
Kristiina Oksman
Keyword(s):  
Energy Storage ◽  
Surface Area ◽  
Renewable Resources ◽  
High Surface ◽  
High Surface Area ◽  
Carbon Aerogel ◽  
Carbon Aerogels ◽  
Electrochemical Characteristics ◽  
Next Generation ◽  
Energy Storage Applications

Various carbon materials have been developed for energy storage applications to address the increasing energy demand in the world. However, the environmentally friendly, renewable, and nontoxic bio-based carbon resources have not been extensively investigated towards high-performance energy storage materials. Here, we report an anisotropic, hetero-porous, high-surface area carbon aerogel prepared from renewable resources achieving an excellent electrical double-layer capacitance. Two different green, abundant, and carbon-rich lignins which can be extracted from various biomasses, have been selected as raw materials, i.e., kraft and soda lignins, resulting in clearly distinct physical, structural as well as electrochemical characteristics of the carbon aerogels after carbonization. The obtained green carbon aerogel based on kraft lignin not only demonstrates a competitive specific capacitance as high as 163 F g−1 and energy density of 5.67 Wh kg−1 at a power density of 50 W kg−1 when assembled as a two-electrode symmetric supercapacitor, but also shows outstanding compressive mechanical properties. This reveals the great potential of the carbon aerogels developed in this study for the next-generation energy storage applications requiring green and renewable resources, lightweight, robust storage ability, and reliable mechanical integrity.

scholarly journals Competitive formation between 2D and 3D metal-organic frameworks: insights into the selective formation and lamination of a 2D MOF

IUCrJ ◽  
2019 ◽  
Vol 6 (4) ◽  
pp. 681-687 ◽  
Author(s):  
Sojin Oh ◽  
Jeehyun Park ◽  
Moonhyun Oh
Keyword(s):  
Active Sites ◽  
High Surface ◽  
Metal Organic Frameworks ◽  
Building Blocks ◽  
Structural Features ◽  
Ultrasonic Dispersion ◽  
Surface Areas ◽  
Metal Organic ◽  
Physical Stimuli ◽  
Selective Formation

The structural dimension of metal–organic frameworks (MOFs) is of great importance in defining their properties and thus applications. In particular, 2D layered MOFs are of considerable interest because of their useful applications, which are facilitated by unique structural features of 2D materials, such as a large number of open active sites and high surface areas. Herein, this work demonstrates a methodology for the selective synthesis of a 2D layered MOF in the presence of the competitive formation of a 3D MOF. The ratio of the reactants, metal ions and organic building blocks used during the reaction is found to be critical for the selective formation of a 2D MOF, and is associated with its chemical composition. In addition, the well defined and uniform micro-sized 2D MOF particles are successfully synthesized in the presence of an ultrasonic dispersion. Moreover, the laminated 2D MOF layers are directly synthesized via a modified bottom-up lamination method, a combination of chemical and physical stimuli, in the presence of surfactant and ultrasonication.

scholarly journals Predicting Hydrogen Storage in MOFs via Machine Learning

2020 ◽  
Author(s):  
Alauddin Ahmed ◽  
Donald Siegel
Keyword(s):  
Machine Learning ◽  
High Surface ◽  
Structural Data ◽  
Structural Features ◽  
Set Size ◽  
Void Fractions ◽  
Surface Areas ◽  
Metal Organic ◽  
Single Input ◽  
And Training

<div><p>The H<sub>2</sub> storage capacities of a diverse set of 918,734 metal-organic frameworks (MOFs) sourced from 19 databases is predicted via machine learning (ML). Using only 7 structural features as input, ML identifies 8,282 MOFs with the potential to exceed the capacities of state-of-the-art materials under physisorptive conditions. The identified MOFs are predominantly hypothetical compounds having low densities (<0.31 g cm<sup>-3</sup>) in combination with high surface areas (> 5,300 m<sup>2</sup> g<sup>-1</sup>), void fractions (~0.90), and pore volumes (>3.3 cm<sup>3</sup> g<sup>-1</sup>). In addition, the relative importance of the input features are characterized, and dependencies on the ML algorithm and training set size are quantified. The single most important features for predicting H<sub>2</sub> uptake are pore volume (for gravimetric capacity) and void fraction (for volumetric capacity). The ML models are available for use via the web, allowing for rapid and accurate predictions of usable hydrogen capacities for MOFs with only minimal structural data as input; for the simplest models only a single input feature is required.</p></div>

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