DOI QR코드

DOI QR Code

A Study on the Improvement of the Electrochemical Performance of Graphite Anode by Controlling Properties of the Coating Pitch

코팅 피치의 물성제어를 통한 흑연 음극재의 전기화학 성능 향상 연구

  • Kim, Bo Ra (C1 Gas & Carbon Convergent Research Center, Korea Research Institute of Chemical Technology) ;
  • Kim, Ji Hong (C1 Gas & Carbon Convergent Research Center, Korea Research Institute of Chemical Technology) ;
  • Kang, Seok Chang (C1 Gas & Carbon Convergent Research Center, Korea Research Institute of Chemical Technology) ;
  • Im, Ji Sun (C1 Gas & Carbon Convergent Research Center, Korea Research Institute of Chemical Technology)
  • 김보라 (한국화학연구원 C1가스탄소융합연구센터) ;
  • 김지홍 (한국화학연구원 C1가스탄소융합연구센터) ;
  • 강석창 (한국화학연구원 C1가스탄소융합연구센터) ;
  • 임지선 (한국화학연구원 C1가스탄소융합연구센터)
  • Received : 2022.06.24
  • Accepted : 2022.07.28
  • Published : 2022.10.10

Abstract

A pitch coating method was proposed for the purpose of improving the electrochemical properties of natural graphite. The synthesis conditions of pitch coating were optimized via measuring electrochemical properties of pitch-coated graphite anodes. As the synthesis temperature increased, the thermal stability was improved in addition to an increase in the softening point and residual carbon weight. However, the synthesis temperature of 430 ℃ resulted in the synthesis of a large amount of NI (NMP Insoluble) due to excessive condensation reaction. As the surface uniformity and coating thickness increased due to high thermal stability, the initial coulombic efficiency and rate capability of the pitch-coated graphite were improved. However, the graphite coated with the pitch containing excessive NI showed lower electrochemical properties than the uncoated graphite. NI had low dispersibility and formed spheres after heat treatment, so it formed the heterogeneous and thicker SEI layer. The optimum conditions for forming a uniform surface and an appropriate coating layer were investigated.

천연 흑연의 전기화학적 특성 향상을 목적으로 피치 코팅을 실시하였다. 최적 코팅용 피치의 합성조건을 알아보기 위해 다양한 온도에서 합성된 피치를 코팅하여 음극 특성을 알아보았다. 합성온도가 증가할수록 연화점, 잔탄율이 증가하며 열적 안정성이 높아졌으나, 430 ℃에서는 과한 축합반응으로 NI (NMP Insoluble)가 다량 합성되었다. 높은 열적 안정성으로 표면의 균일도와 코팅 두께가 증가함에 따라 제조된 음극재의 향상된 초기쿨롱효율과 출력특성의 결과를 얻을 수 있었다. 하지만 과한 NI가 함유된 피치로 코팅한 음극재는 코팅이 실시되지 않은 흑연보다 저하된 전기화학 특성을 나타냈다. NI는 분산성이 낮고 열처리 후 구체 형성의 영향으로 불균일한 SEI층 형성에 기인한다는 결과를 얻을 수 있었다. 피치 합성온도를 제어하여 균일한 표면과 적절한 코팅층 형성이 이루어지는 최적 조건을 도출하였다.

Keywords

Acknowledgement

이 연구는 2022년도 산업통상자원부 및 산업기술평가관리원(KEIT) 연구비 지원에 의한 연구임 ('20007171','20010193')

References

  1. J. Asenbauer, T. Eisenmann, M. Kuenzel, A. Kazzazi, Z. Chen, and D. Bresser, The success story of graphite as a lithium-ion anode material-fundamentals, remaining challenges, and recent developments including silicon (oxide) composites, Sustain. Energy Fuels, 4, 5387-5416 (2020). https://doi.org/10.1039/D0SE00175A
  2. A. Manthiram, An outlook on lithium ion battery technology, ACS Cent. Sci., 3, 1063-1069 (2017). https://doi.org/10.1021/acscentsci.7b00288
  3. D. Bar-Tow, E. Peled, and L. Burstein, A study of highly oriented pyrolytic graphite as a model for the graphite anode in Li-Ion batteries, J. Electrochem. Soc., 146, 824 (1999). https://doi.org/10.1149/1.1391688
  4. Y. J. Han, J. Kim, J. S. Yeo, J. C. An, I. P. Hong, K. Nakabayashi, J. Miyawaki, J. D. Jung, and S. H. Yoon, Coating of graphite anode with coal tar pitch as an effective precursor for enhancing the rate performance in Li-ion batteries: Effects of composition and softening points of coal tar pitch, Carbon, 94, 432-438 (2015). https://doi.org/10.1016/j.carbon.2015.07.030
  5. S. H. Choi, G. Nam, S. Chae, D. Kim, N. Kim, W. S. Kim, J. Ma, J. Sung, S. M. Han, and M. Ko, Robust pitch on silicon nanolayer-embedded graphite for suppressing undesirable volume expansion, Adv. Energy Mater., 9, 1803121 (2019). https://doi.org/10.1002/aenm.201803121
  6. Y. S. Ding, W. N. Li, S. Iaconetti, X. F. Shen, J. D. Carlo, F. S. Galasso, and S. L. Suib, Characteristics of graphite anode modified by CVD carbon coating, Surf. Coat. Technol., 200, 3041-3048 (2006). https://doi.org/10.1016/j.surfcoat.2005.05.040
  7. B. J. Kim, T. Kotegawa, Y. Eom, J. An, I. P. Hong, O. Kato, K. Nakabayashi, J. Miyawaki, B. C. Kim, and I. Mochida, Enhancing the tensile strength of isotropic pitch-based carbon fibers by improving the stabilization and carbonization properties of precursor pitch, Carbon, 99, 649-657 (2016). https://doi.org/10.1016/j.carbon.2015.12.082
  8. 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). https://doi.org/10.1016/S0008-6223(99)00176-1
  9. B. C. Bai, J. G. Kim, J. H. Kim, C. W. Lee, Y. S. Lee, and J. S. Im, Blending effect of pyrolyzed fuel oil and coal tar in pitch production for artificial graphite, Carbon Lett., 25, 78-83 (2018). https://doi.org/10.5714/CL.2018.25.078
  10. Y. J. Han, J. U. Hwang, K. S. Kim, J. H. Kim, J. D. Lee, and J. S. Im, Optimization of the preparation conditions for pitch based anode to enhance the electrochemical properties of LIBs, J. Ind. Eng. Chem., 73, 241-247 (2019). https://doi.org/10.1016/j.jiec.2019.01.031
  11. Y. Castrillejo, A. Martinez, R. Pardo, and G. Haarberg, Electrochemical behaviour of magnesium ions in the equimolar CaCl2-NaCl mixture at 550 ℃, Electrochim. Acta, 42, 1869-1876 (1997). https://doi.org/10.1016/S0013-4686(96)00399-4
  12. 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). https://doi.org/10.1016/j.jiec.2016.02.014
  13. J. H. Kim and H. G. Kim, Characterization of pitch derived from petroleum residue and coal-tar, Trans. Korean Hydrogen New Energy Soc., 27, 612-619 (2016). https://doi.org/10.7316/KHNES.2016.27.5.612
  14. X. H. Fan, W. Li, L. Chen, T. Ouyang, and Y. Fei, Sequential Extraction of Coal Tar Pitch and Structural Characterization of Enriched Large Polycyclic Aromatic Hydrocarbons, ChemistrySelect, 4, 4874-4882 (2019). https://doi.org/10.1002/slct.201900078
  15. Y. Lu, D. Kocaefe, Y. Kocaefe, X. A. Huang, and D. Bhattacharyay, The wettability of coke by pitches with different quinoline-insoluble contents, Fuel, 199, 587-597 (2017). https://doi.org/10.1016/j.fuel.2017.03.019
  16. J. Billaud, F. Bouville, T. Magrini, C. Villevieille, and A. R. Studart, Magnetically aligned graphite electrodes for high-rate performance Li-ion batteries, Nat. Energy, 1, 1-6 (2016).
  17. D. Y. Park, D. Y. Park, Y. S. Lim, and M. S. Kim, High rate capability of carbonaceous composites as anode electrodes for lithium-ion secondary battery, J. Ind. Eng. Chem., 15, 588-594 (2009). https://doi.org/10.1016/j.jiec.2009.03.001
  18. 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). https://doi.org/10.33961/jecst.2019.00528
  19. J. Y. Yang, Y. S. Kuk, M. K. Seo, and B. S. Kim, Thermo-rheological behaviors of Phenolic Resins Blended with Petroleum-based Pitches for High Temperature Carbon Composites, Compos. Res., 33, 329-335 (2020).