Applied Chemistry for Engineering (공업화학)

The Korean Society of Industrial and Engineering Chemistry (한국공업화학회)
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Effect of Mesophase Content Formed During Polymerization of Pyrolysis Residue on the Electrochemical Properties of Synthetic Graphite

열분해 잔사유 중합과정에서 생성되는 이방성 함량이 인조흑연의 결정특성과 전기화학적 특성에 미치는 영향

  • Hye In Son (Chemical & Process Technology Division, Korea Research Institute of Chemical Technology) ;
  • Ji Sun Im (Chemical & Process Technology Division, Korea Research Institute of Chemical Technology)
  • 손혜인 (한국화학연구원 화학공정연구본부) ;
  • 임지선 (한국화학연구원 화학공정연구본부)
  • Received : 2025.08.14
  • Accepted : 2025.09.24
  • Published : 2025.10.10
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Abstract

This study explores the influence of mesophase content in petroleum-derived pitch on the structural and electrochemical properties of synthetic graphite intended for lithium-ion battery anodes. Pitch was synthesized from pyrolyzed fuel oil (PFO) at 360~420 ℃ for 1~5 h. The mesophase content was quantified using polarized optical microscopy and found to increase with elevated synthesis temperature and time. The synthesized pitch was subjected to graphitization at 2700 ℃, and the resulting synthetic graphite was characterized in terms of crystallinity using X-ray diffraction (XRD), Raman spectroscopy, and true density measurements via helium pycnometry. The results revealed that higher mesophase content in the pitch led to enhanced crystallinity in the synthetic graphite. Electrochemical performance was assessed by assembling coin-type half-cells employing lithium metal as the counter electrode. The capacity of synthetic graphite increased with improved crystallinity, while the rate performance showed a decreasing trend. These findings suggest that pitch with high mesophase content is favorable for applications requiring high energy density, whereas lower mesophase content is more suitable for high-rate performance. This work provides insights into tailoring pitch precursors for optimizing synthetic graphite performance in lithium-ion battery applications.

본 연구에서는 이차전지 음극재용 인조흑연 제조를 목적으로 피치의 이방성 함량이 인조흑연의 물성에 미치는 영향을 고찰하였다. 피치는 석유계 잔사유를 원료로 하여 360~420 ℃에서 1~5 h 동안 합성되었으며, 생성된 피치의 이방성 함량은 편광현미경 및 용제분류법을 통해 정성 및 정량적으로 분석되었다. 제조된 인조흑연은 해당 피치를 2700 ℃에서 흑연화하여 제조하였고, 그 결정특성은 X선 회절(X-ray diffraction), 라만 분광법(Raman spectroscopy), 헬륨 밀도 (He-density)를 통해 조사되었다. 그 결과, 열처리 온도 및 시간이 증가할수록 피치의 이방성 함량이 증가하였고, 이방성 함량이 높은 피치로부터 제조된 인조흑연은 향상된 결정특성을 나타냈다. 전기화학적 특성은 리튬 금속을 상대전극으로 한 반쪽 셀로 평가되었으며, 셀의 용량은 결정특성에 비례하여 증가하였다. 반면, 속도 특성은 결정특성이 증가할수록 저하되는 경향을 보였다. 따라서 고용량 특성이 요구되는 경우에는 이방성 함량이 높은 피치를, 고출력 특성이 필요한 경우에는 상대적으로 낮은 이방성 피치를 활용하는 것이 적합할 것으로 판단된다.

Keywords

Acknowledgement

본 연구는 기본사업(한국화학연구원, 저활용 탄소원 활용 수소 생산저장 통합 원천 기술 개발, 과제번호: KK2511-20, 대한민국)과 정부수탁사업(산업통상자원부, 열분해유 기반 배터리 음극소재용 중간원료 제조 기술 개발, 과제번호: TS257-33R, 대한민국)의 지원을 받아 수행되었습니다.

References

  1. H. Zhang, Y. Yang, D. Ren, L. Wang, and X. He, Graphite as anode materials: Fundamental mechanism, recent progress and advances, Energy Storage Mater., 36, 147-170 (2021).
  2. D. Hu, L. Chen, J. Tian, Y. Su, N. Li, G. Chen, Y. Hu, Y. Dou, S. Chen, and F. Wu, Research progress of lithium plating on graphite anode in lithium-ion batteries, Chin. J. Chem., 39, 165-173 (2021).
  3. H. J. Kwon, S. W. Woo, Y. J. Lee, J. Y. Kim, and S. M. Lee, Achieving high-performance spherical natural graphite anode through a modified carbon coating for lithium-ion batteries, Energies (Basel), 14, 1946 (2021).
  4. U. S. Im, J. U. Hwang, J. H. Yun, W. Ahn, K. S. Kim, and J. S. Im, The effect of mild activation on the electrochemical performance of pitch-coated graphite for the lithium-ion battery anode material, Mater. Lett., 278, 128421 (2020).
  5. S. Fischer, S. Doose, J. Müller, C. Höfels, and A. Kwade, Impact of Spheroidization of Natural Graphite on Fast-Charging Capability of Anodes for LIB, Batteries, 9, 305 (2023).
  6. M. xian Wang, C. Y. Wang, T. Q. Li, and Z. J. Hu, Preparation of mesophase-pitch-based carbon foams at low pressures, Carbon, 46, 84-91 (2008).
  7. A. Yadav, R. Kumar, G. Bhatia, and G. L. Verma, Development of mesophase pitch derived high thermal conductivity graphite foam using a template method, Carbon, 49, 3622-3630 (2011).
  8. H. Lee and I. Sohn, Global scrap trading outlook analysis for steel sustainability, J. Sustain. Metall., 1, 39-52 (2015).
  9. W. F. Lamb, T. Wiedmann, J. Pongratz, R. Andrew, M. Crippa, J. G. J. Olivier, D. Wiedenhofer, G. Mattioli, A. Al Khourdajie, J. House, S. Pachauri, M. Figueroa, Y. Saheb, R. Slade, K. Hubacek, L. Sun, S. K. Ribeiro, S. Khennas, S. De La Rue Du Can, L. Chapungu, S. J. Davis, I. Bashmakov, H. Dai, S. Dhakal, X. Tan, Y. Geng, B. Gu, and J. Minx, A review of trends and drivers of greenhouse gas emissions by sector from 1990 to 2018, Environ. Res. Lett., 16, 073005 (2021).
  10. J. R. Kershaw and K. J. T. Black, structural characterization of coal-tar and petroleum pitches, Energy Fuels, 7, 420-425 (1993).
  11. S. Lim, N. Lingappan, and W. Lee, Biased dual-exfoliation technique with expanded graphite for high-quality few-layer graphene sheets in electrochemical exfoliation, Carbon Lett., 35, 1205-1220 (2025).
  12. J. H. Cho and C. Bai, Effects of pressurized PFO-based pitch coking conditions on coke yield and graphite conductivity, Carbon Lett., 31, 921-927 (2021).
  13. N. D. Ristic, M. R. Djokic, E. Delbeke, A. Gonzalez-Quiroga, C.V. Stevens, K. M. Van Geem, and G. B. Marin, Compositional characterization of pyrolysis fuel oil from naphtha and vacuum gas oil, Energy Fuels, 32, 1276-1286 (2018).
  14. M. H. Wagner, H. Jäger, I. Letizia, and G. Wilhelmi, Quality assessment of binder pitches for carbon and graphite electrodes, Fuel, 67, 792-797 (1988).
  15. Y. Lü, L. Ling, D. Wu, L. Liu, B. Zhang, and I. Mochida, Preparation of mesocarbon microbeads from coal tar, J. Mater. Sci., 34, 4043-4050 (1999).
  16. C. Panaitescu and G. Predeanu, Microstructural characteristics of toluene and quinoline-insolubles from coal–tar pitch and their cokes, Int. J. Coal Geol., 71, 448-454 (2007).
  17. J. W. Stadelhofer, R. Marrett, and W. Gemmeke, The manufacture of high-value carbon from coal-tar pitch, Fuel, 60, 877-882 (1981).
  18. S. Y. Mun, J. Hwang, D. H. Yu, S. J. Baek, D. H. Um, D. G. Seong, and K. Y. Cho, Enhancing the frictional performance of lubricant oil-impregnated graphite via oxidation-induced pore expansion and hydrophobic silane treatment, Carbon Lett., Doi:10.1007/s42823-025-00966-8.
  19. H. Jin, C. Kim, S.M. Park, J.C. An, I. Yang, and D. Choi, Coal tar-coated artificial graphite anode derived from polyethylene for lithium-ion batteries, Carbon Lett., 35, 1259-1270 (2025).
  20. S. M. Shin, J. K. Park, and S. M. Jung, Changes of aromatic CH and aliphatic CH in in-situ FT-IR spectra of bituminous coals in the thermoplastic range, ISIJ Int., 55, 1591-1598 (2015).
  21. D. R. Ball, The influence of the type of quinoline insolubles on the quality of coal tar binder pitch, Carbon, 16, 205-209 (1978).
  22. I. Mochida, K. Maeda, and K. Takeshita, Structure of anisotropic spheres obtained in the course of needle coke formation, Carbon, 15, 17-23 (1977).
  23. I. Mochida, Y. Korai, C. H. Ku, F. Watanabe, and Y. Sakai, Chemistry of synthesis, structure, preparation and application of aromatic-derived mesophase pitch, Carbon, 38, 305-328 (2000).
  24. J. H. Kim, Y. J. Choi, J. S. Im, A. Jo, K. B. Lee, and B. C. Bai, Study of activation mechanism for dual model pore structured carbon based on effects of molecular weight of petroleum pitch, J. Ind. Eng. Chem., 88, 251-259 (2020).
  25. J. G. Kim, J. H. Kim, B. J. Song, Y. P. Jeon, C. W. Lee, Y. S. Lee, J. S. Im, Characterization of pitch derived from pyrolyzed fuel oil using TLC-FID and MALDI-TOF, Fuel, 167, 25-30 (2016).
  26. J. G. Kim, J. H. Kim, B. J. Song, C. W. Lee, and J. S. Im, Synthesis and its characterization of pitch from pyrolyzed fuel oil (PFO), J. Ind. Eng. Chem., 36, 293-297 (2016).
  27. J. H. Kim, J. G. Kim, C. W. Lee, K. B. Lee, and J. S. Im, Effect of added mesophase pitch during the pitch synthesis reaction of PFO, Carbon Lett., 23, 48-54 (2017).
  28. I. Mochida, K. Shimizu, Y. Korai, H. Otsuka, Y. Sakai, and S. Fujiyama, Preparation of mesophase pitch from aromatic hydrocarbons by the aid of HFBF3, Carbon, 28, 311-319 (1990).
  29. I. Mochida, K. Kudo, N. Fukuda, K. Takeshita, and R. Takahashi, Carbonization of pitches—IV: Carbonization of polycyclic aromatic hydrocarbons under the presence of aluminum chloride catalyst, Carbon, 13, 135-139 (1975).
  30. S. J. Kim and H. T. Jeong, Development of petroleum pitch/polymer composite binder for anode material of the lithium-ion battery, Carbon Lett., 34, 1031-1037 (2024).
  31. N. R. Calderon, M. Martínez-Escandell, J. Narciso, and F. Rodríguez-Reinoso, The combined effect of porosity and reactivity of the carbon preforms on the properties of SiC produced by reactive infiltration with liquid Si, Carbon, 47, 2200-2210 (2009).
  32. P. Torregrosa-Rodríguez, M. Martínez-Escandell, F. Rodríguez-Reinoso, H. Marsh, C. G. De Salazar, and E. R. Palazón, Pyrolysis of petroleum residues: II. Chemistry of pyrolysis, Carbon, 38, 535-546 (2000).
  33. A. G. Alvarez, M. Martínez-Escandell, M. Molina-Sabio, and F. Rodríguez-Reinoso, Pyrolysis of petroleum residues: analysis of semicokes by X-ray diffraction, Carbon, 37, 1627-1632 (1999).
  34. M. Martínez-Escandell, P. Torregrosa, H. Marsh, F. Rodríguez-Reinoso, R. Santamaría-Ramírez, C. Gómez-De-Salazar, and E. Romero-Palazón, Pyrolysis of petroleum residues: I. Yields and product analyses, Carbon, 37, 1567-1582 (1999).
  35. H. Marsh, M. Martínez-Escandell, and F. Rodríguez-Reinoso, Semicokes from pitch pyrolysis: mechanisms and kinetics, Carbon, 37, 363-390 (1999).
  36. J. J. Kim, S. H. Lee, U. S. Youn, S. U. Gwon, T. S. Byun, and J. S. Roh, Effect of mesophase formation from quinoline insoluble-containing coal tar pitch on physical properties of carbon blocks, Carbon Lett., 34, 1833-1844 (2024).
  37. F. R. Vieira, C. H. M. De Castro Dutra, and L. D. De Castro, Determining the anisotropic content in a petroleum pitch – Comparison of centrifugation and optical microscopy techniques, Fuel, 90, 908-911 (2011).
  38. L. Lu, V. Sahajwalla, C. Kong, and D. Harris, Quantitative X-ray diffraction analysis and its application to various coals, Carbon, 39, 1821-1833 (2001).
  39. B. Manoj and A. G. Kunjomana, Study of stacking structure of amorphous carbon by X-ray diffraction technique, Int. J. Electrochem. Sci., 7, 3127-3134 (2012).
  40. Z. W. Liang, Y. G. Lu, Z. L. Sun, and H. Luo, Polymerization kinetics and control of the components of a mesophase pitch, New Carbon Mater., 35, 591-598 (2020).
  41. X. Py and E. Daguerre, Pitch pyrolysis kinetics: isothermal heat treatment experiments and model, Fuel, 79, 591-598 (2000).
  42. A. Yang, Y. Wang, F. Yang, D. Wang, Y. Zi, K.L. Tsui, and B. Zhang, A comprehensive investigation of lithium-ion battery degradation performance at different discharge rates, J. Power Sources, 443, 227108 (2019).
  43. J. Du, W. Wang, H. Jia, T. Li, and K. Song, High-rate soft carbon anode for lithium storage: from modified pitch molecular structure to ordered carbon microcrystals, Ionics, 31, 151-163 (2025).
  44. S. S. Zhang, K. Xu, and T. R. Jow, EIS study on the formation of solid electrolyte interface in Li-ion battery, Electrochim. Acta, 51, 1636-1640 (2006).
  45. W. Choi, H. C. Shin, J. M. Kim, J. Y. Choi, and W. S. Yoon, Modeling and applications of electrochemical impedance spectroscopy (EIS) for lithium-ion batteries, J. Electrochem. Sci. Technol., 11, 1-13 (2020).
  46. X. Chen, Y. Huang, K. Zhang, X. S. Feng, and M. Wang, Synthesis and high-performance of carbonaceous polypyrrole nanotubes coated with SnS2 nanosheets anode materials for lithium ion batteries, Chem. Eng. J., 330, 470-479 (2017).
  47. P. Bernardo, J. M. Le Meins, L. Vidal, J. Dentzer, R. Gadiou, W. Märkle, P. Novák, M. E. Spahr, and C. Vix-Guterl, Influence of graphite edge crystallographic orientation on the first lithium intercalation in Li-ion battery, Carbon, 91, 458-467 (2015).