전기화학회지 (Journal of the Korean Electrochemical Society)

  • 제24권2호
  • /
  • Pages.28-33
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  • 2021
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  • 1229-1935(pISSN)
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  • 2288-9000(eISSN)
한국전기화학회 (The Korean Electrochemical Society)
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높은 에너지 밀도의 리튬이온 이차전지를 위한 PTFE 바인더를 적용한 고로딩 양극

Thick Positive Electrode using Polytetrafluorethylene (PTFE) Binder for High-Energy-Density Lithium-ion Batteries

  • 강정민 (한국산업기술대학교 생명화학공학과) ;
  • 김형우 (한국산업기술대학교 생명화학공학과) ;
  • 장영석 (한국산업기술대학교 생명화학공학과) ;
  • 김해빈 (한국산업기술대학교 지식기반기술.에너지대학원) ;
  • 류지헌 (한국산업기술대학교 지식기반기술.에너지대학원)
  • Kang, Jeong Min (Department of Chemical Engineering and Biotechnology, Korea Polytechnic University) ;
  • Kim, Hyoung Woo (Department of Chemical Engineering and Biotechnology, Korea Polytechnic University) ;
  • Jang, Young Seok (Department of Chemical Engineering and Biotechnology, Korea Polytechnic University) ;
  • Kim, Haebeen (Graduate School of Knowledge-Based Technology and Energy, Korea Polytechnic University) ;
  • Ryu, Ji Heon (Graduate School of Knowledge-Based Technology and Energy, Korea Polytechnic University)
  • 투고 : 2021.02.14
  • 심사 : 2021.03.25
  • 발행 : 2021.05.31
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초록

이차전지의 에너지 밀도를 높이기 위한 방법으로 전극의 로딩을 높이는 방법에 대하여 많은 시도가 이루어지고 있다. 본 연구에서는 리튬이온 이차전지용 양극에서 보편적으로 사용되어 온 기존의 polyvinylidene fluoride (PVdF) 바인더가 아닌 polytetrafluoroethylene (PTFE) 바인더를 적용하여 고로딩의 LiNi0.5Co0.2Mn0.3O2 (NCM523) 양극을 제조하였다. 기존의 슬러리 공정이 아닌 PTFE 현탁액을 이용한 반죽공정을 통하여 로딩을 높인 두꺼운 전극이 용이하게 제조되었다. PTFE 및 PVdF 기반의 전극을 5.0 mAh/cm2의 로딩레벨로 각각 제조한 결과로 PTFE를 적용한 전극이 좀 더 우수한 사이클 수명과 속도특성을 지니고 있음을 확인하였다. PTFE 바인더를 사용한 반죽공정으로 제조된 전극은 기공도가 커서 전극밀도가 높지 않기 때문에 압연을 상온이 아닌 120℃ 이상의 고온에서 진행함으로써 기공도를 낮출 수 있었으나, 이에 따른 사이클 성능의 차이는 크지 않았다. 또한, 전극조성에서 도전재의 함량을 높임으로써 고로딩 전극의 사이클 수명을 소폭 향상시킬 수 있었다. PTFE 바인더 적용으로 고로딩 전극의 성능을 향상시킬 수 있었으나, 추가적인 개선이 필요할 것이다.

Many researchers have increased the loading level of electrodes to improve the energy density of secondary batteries. In this study, high-loading NCM523 (LiNi0.5Co0.2Mn0.3O2) positive electrode is manufactured using a polytetrafluoroethylene (PTFE) binder, not the conventional polyvinylidene fluoride (PVdF) binder, which has been commonly used in lithium-ion batteries. Through the kneading process using PTFE suspension, not the conventional slurry process using PVdF solution in N-methyl-2-pyrrolidinone (NMP), thick electrodes with high loading are easily manufactured. When the PTFE and PVdF-based electrodes are prepared at a loading level of 5.0 mAh/cm2, respectively, the PTFE-based electrode shows better cycle performance and rate capability than those of PVdF-based electrodes. The electrode manufactured by the kneading process using a PTFE binder has high electrode porosity due to insufficient roll-press, but the porosity can be lowered by high temperature roll-press over 120℃. However, there is no significant difference in cycle performance according to the roll press temperature. In addition, the cycle performance of the high loading electrode is slightly improved by increasing the content of the conductive material. Overall, the PTFE binder can improve the performance of the high loading electrode, but additional solutions will be needed.

키워드

과제정보

이 논문은 2021년도 정부(산업통상자원부)의 재원으로 한국산업기술진흥원의 지원(P0002007, 2021년 산업혁신인재성장지원사업) 및 과학기술정보통신부의 재원으로 한국연구재단의 지원을 받아 수행된 이공분야기초연구사업(NRF-2019R1F1A1058642)의 지원을 받아 수행된 연구임.

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