화학공학소재연구정보센터
홈 로그인 로그아웃 연락처 사이트맵
Korean Chemical Engineering Research, Vol.57, No.5, 672-678, October, 2019
DOI10.9713/kcer.2019.57.5.672  Export Citation
리튬이차전지 음극용 석유계 피치로 코팅된 천연 흑연의 전기화학적 특성
Electrochemical Properties of Natural Graphite coated with PFO-based Pitch for Lithium-ion Battery Anode
김근중, 조윤지, 이종대†
  • 충북대학교 화학공학과, 28644 충청북도 청주시 서원구 충대로 1
Geun Joong Kim, Yoon Ji Jo, and Jong Dae Lee†
  • Department of Chemical Engineering, Chungbuk National University, 1, Chungdaero, Seowon-gu, Cheongju-si, Chungcheongbuk-do, 28644, Korea
E-mail:
초록
리튬이차전지용 음극재로서 피치로 코팅된 천연흑연의 전기화학적 특성이 조사되었다. 천연흑연과 피치의 혼합물을 1000 °C에서 소성하여 음극재를 제조하였다. 다양한 연화점의 피치가 탄소전구체로 사용되었다. 제조된 음극재의 물리적 특성은 TGA, SEM, PSA 및 BET로 분석하였다. 피치의 연화점이 증가할수록 코팅 층의 두께가 증가하였고, 비표 면적이 감소하였다. 초기 충·방전 효율, 사이클, 순환전압전류, 속도 특성 및 임피던스 테스트를 통해 전기화학적 성능을 조사하였다. 연화점 250 °C의 피치로 탄소 코팅된 천연흑연은 초기 방전용량 361 mAh/g과 쿨롱 효율 92.6%을 보였다. 또한 출력 특성(5 C/0.2 C)은 코팅되지 않은 천연흑연에 비해 1.6배 향상되었으며, 0.5 C로 진행된 사이클 테스 트에서 50 사이클 후 90%의 용량 유지율을 나타내었다.
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 °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 °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.
Keywords:Natural graphite;THF;Pitch;Lithium ion battery;Anode
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