Activated carbons prepared from mixtures of coal tar pitch and petroleum pitch and their electrochemical performance as electrode materials for electric double-layer capacitor

Lee, Eunji; Kwon, Soon Hyung; Choi, Poo Reum; Kim, Myung-Soo

doi:10.5714/cl.2015.16.2.078

Cited by 11 publications

(4 citation statements)

References 29 publications

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“…As shown in the Nyquist plot of Figure e, the initial point of a semicircle determines the solution resistance ( R s ), which depends on the electrolyte conductivity and separator. In addition, the final point of the semicircle determines the internal contact resistance ( R c ), which is composed of electronic resistance (including the intrinsic electronic conductivity of particles) and ionic resistance (depending on the electrolyte conductivity and pore texture) . The R s and R c values of H-ST-EH-AC, H-MT-EH-AC, H-OT-EH-AC, and commercial activated carbon are 0.67, 0.97, 1.01, and 0.68 Ω and 2.89, 4.86, 8.58, and 20.1 Ω, respectively.…”

Section: Resultsmentioning

confidence: 99%

Structural and Electrochemical Characteristics of Activated Carbon Derived from Lignin-Rich Residue

Han

Jeong

Lee

et al. 2018

ACS Sustainable Chem. Eng.

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Lignin-rich residue was obtained by sequential acid pretreatment (sulfuric, oxalic, and maleic acid; H-ST, H-OT, and H-MT) and enzymatic hydrolysis (EH). Pretreatment using dicarboxylic acid (oxalic and maleic acid) showed a relatively low solid yield (72.55 and 69.27%) compared with sulfuric acid pretreatment (74.83%). In addition, the enzymatic hydrolysis yield of pretreated biomass differed significantly depending on the acid catalyst used. To investigate structural properties of lignin-rich residue, milled wood lignin (MWL) was extracted. H-MT-EH-MWL and H-OT-EH-MWL were found to have higher M w and polydispersity values than H-ST-EH-MWL, but the syringyl-to-guaiacyl (S/G) ratio of H-ST-EH-MWL was the highest. The lignin-rich residue was used to prepare activated carbons (ACs) to make commercially viable energy storage materials. These activated carbons showed commercially viable specific surface areas (SSAs) (>2000 m2/g) and high rate capabilities (>90% at 50 mA/cm2). H-ST-EH-AC had the highest BET SSA value (2182 m2/g). H-MT-EH-AC had a slightly lower value (2156 m2/g), but H-OT-EH-AC had the lowest value (2079 m2/g). The sp2/sp3 ratio of H-ST-EH-AC (3.8) is higher than the others (H-MT-EH-AC: 3.6 and H-OT-EH-AC: 3.1). On the basis of the lignin-rich residue structure, it is considered the high S-type lignin content of H-ST-EH can be attributed to the graphitic structure in H-ST-EH-AC.

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Section: Resultsmentioning

confidence: 99%

Structural and Electrochemical Characteristics of Activated Carbon Derived from Lignin-Rich Residue

Han

Jeong

Lee

et al. 2018

ACS Sustainable Chem. Eng.

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“…Such materials include activated carbon, activated carbon fibers, carbon nanofibers, graphite nanofibers (GNFs), mesoporous carbons, and graphite [16][17][18][19][20][21][22]. Among these, activated carbons and activated carbon fibers have been widely used in the field of CO 2 adsorption.…”

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confidence: 99%

KOH-activated graphite nanofibers as CO₂adsorbents

Yuan¹,

Meng²,

Park³

2016

Carbon letters

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Porous carbons have attracted much attention for their novel application in gas storage. In this study, porous graphite nano-fiber (PGNFs)-based graphite nano fibers (GNFs) were prepared by KOH activation to act as adsorbents. The GNFs were activated with KOH by changing the GNF/KOH weight ratio from 0 through 5 at 900°C. The effects of the GNF/ KOH weight ratios on the pore structures were also addressed with scanning electron microscope and N 2 adsorption/desorption measurements. We found that the activated GNFs exhibited a gradual increase of CO 2 adsorption capacity at CK-3 and then decreased to CK-5, as determined by CO 2 adsorption isotherms. CK-3 had the narrowest micropore size distribution (0.6-0.78 nm) among the treated GNFs. Therefore, KOH activation was not only a significant method for developing a suitable pore-size distribution for gas adsorption, but also increased CO 2 adsorption capacity as well. The study indicated that the sample prepared with a weight ratio of '3' showed the best CO 2 adsorption capacity (70.8 mg/g) as determined by CO 2 adsorption isotherms at 298 K and 1 bar. Key words: activated graphite nanofibers, KOH treatment, CO 2 adsorptionThe rapid increase of the greenhouse gas carbon dioxide (CO 2 ) in the atmosphere is generally thought to be a major factor in climate change. These changes are increasingly viewed as a threat to both the global economy and the natural environment [1][2][3][4]. This increase in CO 2 is mainly attributed to human activities [5][6][7][8][9][10]. However, methane (bases: CH 4 50%-70%, CO 2 30%-40%) is one of reproducible biomass energy, which can obtain available energy sources, but also generate abundant greenhouse gas that goes against the purity of CH 4 [10]. It is essential to find an ideal material to work out the austere problem. Usually, CO 2 capture and storage is an efficient green technology used to reduce emissions by transporting and storing CO 2 in deep geologic formations. The capture methods can be classified as post-combustion, pre-combustion, and air separation followed by oxyfuel combustion [7]. Among the currently available technologies, post-combustion is the most easily applied technology. It involves use of absorption, adsorption, cryogenic distillation, membranes, and gas hydrates.Up to now, high-performance adsorbents have been widely used for CO 2 capture. Conventional solid adsorbents include zeolites [11], activated carbon [12], mesoporous silica [13], metal oxide-based adsorbents (e.g., MgO and CaO) [14], and metal-organic frameworks (MOFs) [15]. Nevertheless, in each case, there are defects in the adsorption process. Zeolites and mesoporous silica have the drawback of poor CO 2 capture performance. With zeolites, adsorption of moisture could affect the stability of the zeolite frameworks, and demands high regeneration temperature (>573 K). This results in huge energy consumption for CO 2 desorption. Meanwhile, although the adsorption capacity for CO 2 of activated carbon is high due to pore sizes ranging from micr...

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“…There is ah uge increase in the C/H molar ratio, as shown in Figure S1 b( in the Supporting Information), implying that the molecular aromaticity increases and the condensation degree deepens. [15,28,29] The change of characteristic peaks for aliphatic (2920/1440 cm À1 )a nd aromatic (3045/700-900 cm À1 ) [30,31] hydrocarbons in the infrared spectra also supports this point. The parameter CH 2 /CH 3 ,evaluated by the ratio of A 2920 and A 2950 (A represents the area of the peak), was introduced to evaluatet he length of aliphatic side chains.…”

Section: Resultsmentioning

confidence: 56%

Pitch‐Based Laminated Carbon Formed by Pressure Driving at Low Temperature as High‐Capacity Anodes for Lithium Energy Storage Systems

Yang

Song

Tian

et al. 2020

Chemistry A European J

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Pitch hasb een used to prepare electrodes by high-temperature heat treatments for supercapacitors, lithium-ion batteries, on account of its rich aromatic ring structure. Here, the toluene-soluble component of pitch is used to prepare ak ind of laminated carbon.T his was realized by at emplate-free synthesis at low temperature with the addition of pressure. Thet oluene-soluble component has as mall molecular weight, which makes the thermal deformation ability stronger and then enhances the orientation of the carbon layer with the help of pressure. The prepared anode exhibits as plendid electrochemical performance compared with the traditional graphite anode. Ah igh stable capacity of approximately 550 mAh g À1 at 50 mA g À1 ,w hich is much higher than graphite (372 mAh g À1), is obtained. Also, when the current density is up to 2Ag À1 ,t he capacity is about 150 mAh g À1 .S urprisingly,i ta lso delivers as uperior cycling performance. And when used as the anode/cathode electrode for lithium-ion capacitors, ah igh energy density can be obtained. The present work offers an opportunity to utilize the pitch source in lithium energy storagew ith promising cycle life, high energy/power density,a nd low cost.

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Activated carbons prepared from mixtures of coal tar pitch and petroleum pitch and their electrochemical performance as electrode materials for electric double-layer capacitor

Cited by 11 publications

References 29 publications

Structural and Electrochemical Characteristics of Activated Carbon Derived from Lignin-Rich Residue

Structural and Electrochemical Characteristics of Activated Carbon Derived from Lignin-Rich Residue

KOH-activated graphite nanofibers as CO₂adsorbents

Pitch‐Based Laminated Carbon Formed by Pressure Driving at Low Temperature as High‐Capacity Anodes for Lithium Energy Storage Systems

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Activated carbons prepared from mixtures of coal tar pitch and petroleum pitch and their electrochemical performance as electrode materials for electric double-layer capacitor

Cited by 11 publications

References 29 publications

Structural and Electrochemical Characteristics of Activated Carbon Derived from Lignin-Rich Residue

Structural and Electrochemical Characteristics of Activated Carbon Derived from Lignin-Rich Residue

KOH-activated graphite nanofibers as CO2adsorbents

Pitch‐Based Laminated Carbon Formed by Pressure Driving at Low Temperature as High‐Capacity Anodes for Lithium Energy Storage Systems

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KOH-activated graphite nanofibers as CO₂adsorbents