Applied Chemistry for Engineering (공업화학)

The Korean Society of Industrial and Engineering Chemistry (한국공업화학회)
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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
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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')

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