• Title/Summary/Keyword: Petroleum pitch

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Electrochemical Properties of Natural Graphite coated with PFO-based Pitch for Lithium-ion Battery Anode (리튬이차전지 음극용 석유계 피치로 코팅된 천연 흑연의 전기화학적 특성)

  • Kim, Geun Joong;Jo, Yoon Ji;Lee, Jong Dae
    • Korean Chemical Engineering Research
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    • v.57 no.5
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    • pp.672-678
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    • 2019
  • The electrochemical properties of pitch-coated natural graphite(NG) were investigated as an anode for lithium-ion batteries. The anode materials were prepared by heat-treatment of mixture of NG and petroleum pitch at $1000^{\circ}C$. The pitches with various softening points were used as carbon precursor. The physical properties of anode materials were analyzed by TGA, SEM, PSA and BET. As the softening point increased, the thickness of the coating layer increased and the specific surface area decreased. The electrochemical performances were investigated by initial charge/discharge efficiency, cycle stability, cyclic voltammetry, rate performance and electrochemical impedance spectroscopy. The carbon-coated NG using pitch with softening points of $250^{\circ}C$ showed an initial discharge capacity of 361 mAh/g and a coulombic efficiency of 92.6%. Also, the rate performance(5 C/0.2 C) was 1.6 times higher than that of NG, and it had a capacity retention (90%) after 50 cycles at 0.5 C.

Electrochemical Performances of Spherical Silicon/Carbon Anode Materials Prepared by Hydrothermal Synthesis (수열 합성법으로 제조된 구형의 실리콘/탄소 음극소재의 전기화학적 특성)

  • Choi, Na Hyun;Lee, Jong Dae
    • Korean Chemical Engineering Research
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    • v.59 no.3
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    • pp.326-332
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    • 2021
  • In this study, a spherical carbon composite material containing nano-silicon was synthesized using hydrothermal synthesis, and coated with petroleum pitch to prepare an anode material to investigate the electrochemical characteristics. Hydrothermal synthesis was performed by varying molar concentration, and the pitch was coated using THF as an organic solvent to prepare a composite material. The physical properties of anode materials were analyzed using SEM, EDS, XRD and TGA, and the electrochemical performances were investigated by cycle, C-rate, cyclic voltammetry and electrochemical impedance tests in 1.0 M LiPF6 electrolyte (EC : DMC : EMC = 1 : 1 : 1 vol%). The pitch-coated silicon/carbon composite (Pitch@Si/C-1.5) with sucrose of 1.5 M showed a spherical shape. In addition, a high initial capacity of 1756 mAh/g, a capacity retention ratio of 82% after 50 cycles, and an excellent rate characteristic of 81% at 2 C/0.1 C were confirmed.

Development of Gold Phosphorus Supported Carbon Nanocomposites

  • Mayani, Vishal J.;Mayani, Suranjana V.;Kim, Sang Wook
    • Bulletin of the Korean Chemical Society
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    • v.35 no.2
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    • pp.401-406
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    • 2014
  • Metal-containing carbon nanocomposites have shown significance promise in the area of energy storage, heterogeneous catalysis and material science because of their morphology and combined properties. Phosphorus-doped carbon nanocomposites with gold nanoparticles were developed by applying a simple impregnation method and metal deposition technique. Gold-phosphorus supported carbon nanocomposites with two sized (25 and 170 nm) were prepared from economical petroleum pitch residue as the carbon source using an advanced silica template method. These nanocomposites will lead to the novel applications in the field of material science with the combined properties of gold, phosphorus and carbon. The newly prepared gold phosphorus supported carbon nanocomposites were fully characterized using a range of different physico-chemical techniques.

Enhanced Removal Efficiency of Low-Concentration Cesium Ion in Water Phase by Using Petroleum Residue Pitch (석유계 잔사유 피치를 이용한 수중에서 저농도 세슘 이온의 제거효율 향상)

  • Choi, Tae Ryeong;Ha, Jeong Hyub;Choi, Suk Soon
    • Journal of the Korea Organic Resources Recycling Association
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    • v.29 no.4
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    • pp.25-31
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    • 2021
  • In this research, in order to effectively utilize the petroleum residue pitch, it was used as an adsorbent for removal of cesium ion. In this experiment, acid modification (hydrochloric acid, sulfuric acid) treatment was performed on the adsorbent to improve the ability to remove low-concentration cesium ions dissolved in water. As a result, when the reaction was performed with 9 M sulfuric acid at 25 ℃ and for 240 min, the removal efficiencies of 1.0 and 2.5 mg/L cesium ions were 66 and 51%, respectively. In addition, as the adsorption time increased in the batch experiment, the removal capacity of 1.0 and 2.5 mg/L cesium ions was improved, and when the adsorption reached for 32 hr, the removal efficiencies were 72 and 68%, respectively. Also, in order to increase the ability to remove the remaining cesium ions, an experiment was performed by temperature change (25, 37, 49 ℃), and 1.0 and 2.5 mg/L cesium ions contained in water under the operating conditions of 49 ℃ and 32 hr showed removal efficiencies of 90 and 81%, respectively. Consequently, these experimental results were intended to be used as an adsorption technology that can economically treat low-concentration cesium ions contained in water.

Identification of Synthesized Pitch Derived from Pyrolyzed Fuel Oil (PFO) by Pressure (석유계 잔사유(PFO)의 피치 합성 시 압력조건에 따른 피치 특성 변화)

  • Seo, Sang Wan;Kim, Ji Hong;Lee, Young-Seak;Im, Ji Sun
    • Applied Chemistry for Engineering
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    • v.29 no.6
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    • pp.652-656
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    • 2018
  • In this study, effects of the reaction pressure were studied for petroleum-based pitch synthesis. A two-stage reaction process was performed based on different reaction pressure conditions. Each stage experiments for the two-stage reaction were consecutively carried out. The first stage was consisted of three different pressure conditions; high (10 bar), normal and low (0.1 bar). And the second stage was carried out at the normal and low (0.1 bar) pressure. The pitch synthesis was realized at $400^{\circ}C$ for 2 h. Thermal properties and molecular weight distributions of each samples were investigated by analyzing the softening point and MALDI-TOF data. Volatilized components during the pith synthesis were measured by GC-SIMDIS. In case of the first-step reaction with the high pressure condition, the low molecular weight component participated to the pitch formation more effectively and the pitch with the low softening point was obtained. However, for the case of the first-step with the low pressure, the low molecular weight component was vent outside and the partial coke formation occurred. Eventually, pitch properties such as the softening point and yield were controlled effectively by changing the pressure in the pitch synthesis reaction.

Electrochemical Performance of Graphite/Silicon/Pitch Anode Composites Bonded with Graphite Surface PVP and Silica Amine Function Group (흑연 표면의 PVP와 실리카의 아민 작용기로 결합된 흑연/실리콘/피치 음극 복합소재의 전기화학적 성능)

  • Lee, Su Hyeon;Lee, Jong Dae
    • Korean Chemical Engineering Research
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    • v.57 no.1
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    • pp.118-123
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    • 2019
  • In this study, the electrochemical characteristics of Graphite/Silicon/Pitch anode composites were analyzed to improve the low theoretical capacity of graphite as a lithium ion battery. The Graphite/Silica composites were synthesized by bonding silica onto polyvinylpyrrolidone coated graphite. The surface of used silica was treated with (3-Aminopropyl)triethoxysilane(APTES). Graphite/Silicon/Pitch composites were prepared by carbonization of petroleum pitch, the fabrication processes including the magnesiothermic reduction of nano silica to obtain silicon and varying the mass ratio of silica. The Graphite/Silicon/Pitch composites were analysed by XRD, SEM and XRD. Also the electrochemical performances of Graphite/Silicon/Pitch composite as the anode of lithium ion battery were investigated by constant current charge/discharge, rate performance, cyclic voltammetry and electrochemical impedance tests in the electrolyte of $LiPF_6$ dissolved in organic solvents (EC:DMC:EMC=1:1:1 vol%). The Graphite/Silicon/Pitch anode composite (silica 28.5 in weight) has better capacity (537 mAh/g). The cycle performance has an excellent capacity retention to 30th cycle of 95% and the retention rate capability of 98% in 0.1 C/0.2 C.

Electrochemical Characteristics of the Activated Carbon Electrode Modified with the Microwave Radiation in the Electric Double Layer Capacitor (전기이중층캐패시터에서 마이크로파에 의해 개질된 활성탄소전극의 전기화학적 특성)

  • Sun, Jin-Kyu;Um, Eui-Heum;Lee, Chul-Tae
    • Applied Chemistry for Engineering
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    • v.21 no.1
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    • pp.11-17
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    • 2010
  • Modifying surface of activated carbon for the electrode of EDLC with an organic electrolyte was investigated to improve the electrochemical performance of EDLC by the microwave radiation. Three kinds of activated carbons, prepared activated carbon from petroleum cokes and pitch cokes and commercial activated carbon BP-25, were used for this study. For all investigated activated carbons, hydrophilic functional groups-containing oxygen disappeared from the surface of activated carbon as microwave radiation. And as microwave radiation time was increased, the specific surface area and total pore volume of activated carbons were reduced and average pore diameter were increased. From theses effects, interfacial resistance of EDLC with the modified activated carbon electrode was drastically decreased, and discharge capacitance was increased although the specific surface area of activated carbon was reduced by this microwave radiation.

Charge-Discharge Characteristics of Carbonaceous Materials for a Negative Electrode in Lithium-Ion Batteries (리튬이온전직용 카본계부극재료의 충방전 특성)

  • 김정식;박영태;김상열;장영철
    • Journal of the Microelectronics and Packaging Society
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    • v.6 no.2
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    • pp.69-74
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    • 1999
  • Graphite and carbonaceous materials intercalate and deintercalate Li-ion reversibly into their layered structures. These materials show an excellent capacity for using a negative electrode in Li-ion batteries, because the electrochemical potential of Li-ion intercalated carbon is almost identical with that of lithium metal. Carbon used in this study was obtained by the pyrolysis of petroleum pitch, and heat-treated at the several temperatures between $700^{\circ}C$ and $1300^{\circ}C$. XRD analysis revealed that crystallization of carbon increased with increasing the heat treatment temperature. Charge/discharge properties were studied by a constant-current step at the rate of 0.1C, and the interfacial reaction between the electrolyte and the surface of carbon electrode was studied by cyclic voltammetry. Cell capacities were investigated in terms of the heat treatment temperature and the cycle number. Reversible capacity increased with the heat treatment temperature up to $1000^{\circ}C$, thereafter decreased continuously. Also, charge capacity decreased with the cycle number, while the reversibility improved with it.

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Effects of Pitch Softening Point-based on Soft Carbon Anode for Initial Efficiency and Rate Performance (피치계 소프트 카본 음극재 제조 시 피치의 연화점이 음극재 초기 효율 및 율속 특성에 미치는 영향)

  • Kim, Kyung Soo;Im, Ji Sun;Lee, Jong Dae;Kim, Ji Hong;Hwang, Jin Ung
    • Applied Chemistry for Engineering
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    • v.30 no.3
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    • pp.331-336
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    • 2019
  • In this study, required properties and optimized procedure conditions for the pitch based soft carbon anode of lithium ion battery was investigated for improving the initial efficiency and rate performance. Each petroleum residue was thermally treated at 360, 370, and $410^{\circ}C$ for 3 hours to synthesis a pitch and the corresponding pitch shows the softening point of 86, 98, and $152^{\circ}C$, respectively. The elemental analysis and thermal characteristics of the pitch were investigated by EA analysis and TGA. It was noted that the low H/C and improved thermal stability were obtained with the high softening point. The obtained pitch was carbonized at $1,200^{\circ}C$ for 1 hour to produce a soft carbon based anode. As a result of investigating the crystal structure by XRD analysis, it was found that the crystallinity of soft carbon increased with increasing the softening point. It was considered that relatively higher boiling components and decreases in the evaporation component resulted the components participation for cyclization during the heat treatment process. The soft carbon based anode with an improved crystallinity shows the enhanced initial efficiency and rate performance. The mechanism of both improvements was also discusssed based on the developed crystal structure of soft carbon based anode materials.

Electrochemical Characteristics of Silicon/Carbon Anode Materials using Petroleum Pitch (석유계 피치를 사용한 실리콘/탄소 음극소재의 전기화학적 특성)

  • Lee, Su Hyeon;Lee, Jong Dae
    • Korean Chemical Engineering Research
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    • v.56 no.4
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    • pp.561-567
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    • 2018
  • In this study, the electrochemical characteristics of Silicon/Carbon anode materials were analyzed to improve the cycle stability of silicon as an anode materials of lithium ion battery. Porous silicon was prepared from TEOS by the $st{\ddot{o}}ber$ method and the magnesiothermic reduction method. Silicon/Carbon anode materials were synthesized by varying the mass ratio between porous silicon and pitch. Physical properties of the prepared Silicon/Carbon anode materials were analyzed by XRD and TGA. Also the electrochemical performances of Silicon/Carbon anode materials were investigated by constant current charge/discharge, rate performance, cyclic voltammetry and electrochemical impedance tests in the electrolyte of $LiPF_6$ dissolved in organic solvents (EC : DEC = 1 : 1 vol%). The Silicon/Carbon anode composite (silicon : carbon = 5 : 95 in weight) has better capacity (453 mAh/g) than those of other composition cells. The cycle performance has an excellent capacity retention from 2nd cycle to 30th cycle.