Effect of coke orientation on the electrochemical properties of lithium-ion battery anode

Lee, Seung Eun; Kim, Ji Eun; Lee, Young-Seak; Im, Ji Sun

doi:10.1007/s10800-021-01581-x

Cited by 12 publications

(8 citation statements)

References 28 publications

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“…stored in irregular hexagonal planes and surface sites, and in clusters between graphene crystals [33]. The rate of performance (5 C/0.2 C) of the pyrolyzed pitch was 48.55%, which had a similar performance to that of CFG20 (48.26%), while it was greatly lower than that of CFG5 (80.58%).…”

Section: Reason For the Improved Electrochemical Performance Of Pitch...mentioning

confidence: 93%

“…The pyrolyzed pitch had a plateau at a low potential of 0.05 V as shown in Figure S4, which shows a similar behavior to a soft carbon structure. It has various lithium adsorption/desorption sites, and lithium ions can be stored in irregular hexagonal planes and surface sites, and in clusters between graphene crystals [33]. The rate of performance (5 C/0.2 C) of the pyrolyzed pitch was 48.55%, which had a similar performance to that of CFG20 (48.26%), while it was greatly lower than that of CFG5 (80.58%).…”

Section: Reason For the Improved Electrochemical Performance Of Pitch...mentioning

confidence: 96%

“…The particles are oriented in a direction perpendicular to the current collector under the force generated during the electrode rolling process [37][38][39]. The pitch coated on the graphite surface imparts a more spherical particle shape because of which the spherical particles are relieved of their orientation [33,40], thus facilitating the diffusion of lithium ions. The density and electronic conductivity were evaluated under loads varying from 400 to 2000 kgf using the powder resistivity measurement system, as shown in Figure S8.…”

Section: Reason For the Improved Electrochemical Performance Of Pitch...mentioning

confidence: 99%

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Effect and Mechanism of Pitch Coating on the Rate Performance Improvement of Lithium-Ion Batteries

Kim

2022

Materials

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This study evaluated the effect of pitch coating on graphite anode materials used in lithium-ion batteries and investigated the mechanism whereby pitch coating improves the electrochemical properties. The FG (flake graphite) and pitch were mixed in weight ratios of 95:5–80:20. The mixture was pressed and prepared into a block form. Additionally, heat treatment was performed at 900 °C for 1 h and pulverized in the size range of 10–25 μm. The results showed that the particles of uniform pitch-coated graphite became more spherical. However, when the pitch is added excessively, pitch aggregation occurs rather than a thicker coating, indicating a nonuniform particle shape. Pitch has a randomly oriented structure and a small crystal size. Therefore, pitch serves as a lithium-ion diffusion pathway, resulting in an improved rate of performance. Notably, the uniform pitch-coated graphite exhibited an outstanding rate of performance owing to the relieving of particle orientation in the electrode rolling process. During the rolling process, the particles are oriented perpendicular to the lithium-ion diffusion pathway, making it difficult for the lithium ions to diffuse. Adding an excessive amount of pitch was found to deteriorate the rate of performance. Pitch aggregation increased the interfacial resistance by forming a heterogeneous surface.

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Section: Reason For the Improved Electrochemical Performance Of Pitch...mentioning

confidence: 93%

Section: Reason For the Improved Electrochemical Performance Of Pitch...mentioning

confidence: 96%

Section: Reason For the Improved Electrochemical Performance Of Pitch...mentioning

confidence: 99%

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Effect and Mechanism of Pitch Coating on the Rate Performance Improvement of Lithium-Ion Batteries

Kim

2022

Materials

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“…In recent years, the gradual development of coal-based carbon materials has attracted the widespread attention of most scholars. As an important carbon material, needle coke has the characteristics of high mechanical strength, high conductivity, and low thermal expansion efficiency, which can be used to prepare high-power graphite electrodes, lithium-ion battery anode materials, and electrode materials for supercapacitors. − The raw materials for needle coke are divided into two types, including oil-based and coal-based. However, the supply of raw materials will be unstable with the increasing shortage of petroleum resources, which will affect the quality of needle coke .…”

Section: Introductionmentioning

confidence: 99%

Optimizing the Preparation Process of Refined Asphalt Based on the Response Surface and Preparation of Needle Coke

Wei,

Jiang

2024

ACS Omega

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Refined asphalt was prepared by solvent extraction sedimentation based on the response surface design, using washing oil and kerosene as solvents and the coal tar pitch as raw materials. The mathematical models of the refined asphalt yield, quinoline insoluble (QI) content, ash content, solvent-to-oil ratio, aromaticto-aliphatic hydrocarbon ratio, extraction temperature, and sedimentation time were proposed, analyzing the influence of each factor and their interactions on the response values. Therefore, the optimal combination of preparation process parameters and better operation window was obtained by optimizing the experiment. Meanwhile, refined asphalt with high QI content and low QI content was selected as raw material, and the needle coke was prepared through the process of carbonization and calcination. The influence of QI content on the composition and the structure of green coke and needle coke was investigated by X-ray diffraction (XRD), Raman spectra, and polarizing microscopy characterizations. The results showed that the solvent-to-oil ratio is 1.2, aromatic-to-aliphatic hydrocarbon ratio is 1.1, sedimentation time is 2 h, and extraction temperature is 110 °C, resulting in the yield of refined asphalt being 76%, QI content being less than 0.1%, and ash content being less than 0.05%, which meets the requirement of the high-quality needle coke. Otherwise, refined asphalt with lower QI content easily generates a mesophase with more fibers and a large structure in the thermal conversion process, and the corresponding green coke and needle coke have a relatively regular carbon microcrystalline structure.

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“…However, there are few reports on how to balance the carbon microcrystalline alignment structures and defect degree to obtain porous carbon-based electrode materials with a high graphitization, high SSA value, and large compaction density to achieve high mass loading of the electrode. Needle coke is an easily overlooked precursor of activated carbon with good optical anisotropy and dense needle-like fiber structures, which endow it with a large compaction density, high mechanical strength, low thermal expansion coefficient, good electrical conductivity, and ease of graphitization . The inherent anisotropy of needle coke can significantly enhance the electrical conductivity of the carbon material products, while the oriented needle fiber structures enable the porous carbon material to achieve the rapid transport of ions and electrons.…”

Section: Introductionmentioning

confidence: 99%

Short-Range Ordered Porous Carbon Derived from Confined-Region Activation Strategy Exhibits Excellent High-Loading Performance in Supercapacitors

Zhao,

Sun,

Sun

et al. 2024

ACS Sustainable Chem. Eng.

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Constructing high-loading (>10 mg/cm 2 ) carbon-based electrode materials is an effective way to simultaneously boost the gravimetric/volumetric energy density and power density of capacitors. However, porous carbon materials usually have high defect structures, low compaction density, and low graphitization degree, which severely hinder their electron/ion transport rates at high mass loading, thereby deteriorating the electrochemical performance. Thus, we first propose to construct short-range ordered porous carbon materials with high compaction density to enhance the detailed electrochemical performance without affecting the electron/ion transport rates. Herein, S, N codoped porous carbon (3SN-NAC-800) with a large specific surface area, high compaction density, and abundant short-range ordered structures was prepared by the confined-region activation method, in which needle coke was used as precursor, thiourea as the dopant, and KOH as the activator under 10 MPa pressure. The 3SN-NAC-800 electrode with 4 mg/cm 2 exhibits high capacities of 267.2 and 229.7 F/g under 2 and 50 A/g, respectively, and 92.9% capacitance retention for 20,000 cycles. When the mass loading was increased to 8, 12, and 14 mg/cm 2 , it still exhibited high capacities of 260.4, 257.5, and 250.4 F/g at 2 A/g, respectively. Besides, the electrode with 12 mg/cm 2 shows high gravimetric and areal capacitance values of 197.3 F/g and 2367.12 mF/cm 2 at 40 A/g, respectively, as well as 90.98% capacity retention for 20,000 cycles, showing excellent rate capability and cycling stability. Furthermore, it exhibits a maximum energy density of 0.11 mWh/cm 2 at 2.97 mW/cm 2 , and a maximum power density of 87.6 mW/cm 2 at 0.044 mWh/cm 2 . This work demonstrates an efficient strategy to prepare short-range ordered porous carbon materials for high-mass-loading capacitors.

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Effect of coke orientation on the electrochemical properties of lithium-ion battery anode

Cited by 12 publications

References 28 publications

Effect and Mechanism of Pitch Coating on the Rate Performance Improvement of Lithium-Ion Batteries

Effect and Mechanism of Pitch Coating on the Rate Performance Improvement of Lithium-Ion Batteries

Optimizing the Preparation Process of Refined Asphalt Based on the Response Surface and Preparation of Needle Coke

Short-Range Ordered Porous Carbon Derived from Confined-Region Activation Strategy Exhibits Excellent High-Loading Performance in Supercapacitors

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