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3차원 구조 모델링을 이용한 활물질 입자 크기 및 전극 밀도에 따른 복합 전극 내 물리적 특성 분석

Physical Property Analysis of Composite Electrodes with Different Active Material Sizes and Densities using 3D Structural Modeling

  • 양승원 (대구경북과학기술원 에너지공학전공) ;
  • 박주남 (대구경북과학기술원 에너지공학전공) ;
  • 변승우 (대구경북과학기술원 에너지공학전공) ;
  • 김나연 (대구경북과학기술원 에너지공학전공) ;
  • 유명현 (한밭대학교 화학생명공학과) ;
  • 이용민 (대구경북과학기술원 에너지공학전공)
  • Yang, Seungwon (Department of Energy Science and Engineering, Daegu Gyeongbuk Institute of Science and Technology (DGIST)) ;
  • Park, Joonam (Department of Energy Science and Engineering, Daegu Gyeongbuk Institute of Science and Technology (DGIST)) ;
  • Byun, Seoungwoo (Department of Energy Science and Engineering, Daegu Gyeongbuk Institute of Science and Technology (DGIST)) ;
  • Kim, Nayeon (Department of Energy Science and Engineering, Daegu Gyeongbuk Institute of Science and Technology (DGIST)) ;
  • Ryou, Myung-Hyun (Department of Chemical and Biological Engineering, Hanbat National University) ;
  • Lee, Yong Min (Department of Energy Science and Engineering, Daegu Gyeongbuk Institute of Science and Technology (DGIST))
  • 투고 : 2020.02.07
  • 심사 : 2020.04.10
  • 발행 : 2020.05.31

초록

이차전지용 전극은 일반적으로 전극 활물질, 도전재, 그리고 고분자 바인더가 혼합된 복합 전극의 형태를 갖는다. 따라서, 크기나 형태가 다른 각 성분의 조성 및 전극 내 분포에 따라 전극의 전기화학적 활성이 달라지게 되나, 이를 효율적으로 예측하고 설계하는 3차원 전극 구조 모델링 기술은 아직 활발히 연구되고 있지 못하다. 따라서, 본 논문에서는 3차원 구조 모델링 툴인 GeoDict를 이용하여, LiCoO2 전극 활물질 입자 크기와 복합 전극 밀도에 따른 입자 간 접촉 면적과 전기전도특성을 예측한 결과를 제시한다. 전극의 조성과 로딩은 LiCoO2 : Super P Li® : Polyvinylidene Fluoride (PVdF) = 93 : 3 : 4 (wt%)과 13 mg cm-2로 고정하고, LiCoO2 평균 입경은 10 ㎛과 20 ㎛로 전극 밀도는 2.8 g cm-3, 3.0 g cm-3, 3.2 g cm-3, 3.5 g cm-3, 4.0 g cm-3로 제어하여 가상의 3차원 전극 구조를 만들었다. 이 구조를 활용하여 LiCoO2 입경 증가에 따른 입자 간 접촉 면적 감소와 전기전도특성 증가 경향성이 정량화되었다. 또한, 전극 밀도가 증가함에 따라 입자 간 접촉 면적 및 전기전도특성 향상도 수치화 된 값으로 예상될 수 있다. 따라서, 본 논문에서는 3차원 전극 구조 분석 기법을 이용하면, 더 효율적인 복합 전극 설계가 가능함을 제시한다.

Composite electrodes for rechargeable batteries generally consist of active material, electric conductor, and polymeric binder. And their composition and distribution within the composite electrode determine the electrochemical activity in the electrochemical systems. However, it is not easy to quantify the physical properties of composite electrodes themselves using conventional experimental analysis tools. So, 3D structural modeling and simulation can be an efficient design tool by looking into the contact areas between particles and electric conductivity within the composite electrode. In this study, while maintaining the composition (LiCoO2 : Super P Li® : Polyvinylidene Fluoride (PVdF) = 93 : 3 : 4 by wt%) and loading level (13 mg cm-2) of the composite electrode, the effects of LiCoO2 size (10 ㎛ and 20 ㎛) and electrode density (2.8 g cm-3, 3.0 g cm-3, 3.2 g cm-3, 3.5 g cm-3, 4.0 g cm-3) on the physical properties are investigated using a GeoDict software. With this tool, the composite electrode can be efficiently designed to optimize the contact area and electric conductivity.

키워드

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