Korean Chemical Engineering Research

The Korean Institute of Chemical Engineers (한국화학공학회)
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Charge-Discharge Characteristics of Lithium Metal Polymer Battery Adopting PVdF-HFP/(SiO2, TiO2) Polymer Electrolytes Prepared by Phase Inversion Technique

상반전 기법으로 제조한 PVdF-HFP/(SiO2, TiO2) 고분자 전해질을 채용한 리튬금속 고분자 2차전지의 충방전 특성

  • Kim, Jin-Chul (School of Biotechnology and Bioengineering, and Institute of Bioscience and Biotechnology, Kangwon National University) ;
  • Kim, Kwang-Man (Ionics Devices Team, IT-NT Group, IT Convergence & Components Lab., Electronics & Telecommunications Research Institute (ETRI))
  • 김진철 (강원대학교 BT 특성화학부 대학 생물소재공학 전공) ;
  • 김광만 (한국전자통신연구원 IT 부품융합연구소 IT-NT 그룹 이오닉스소자팀)
  • Received : 2007.08.22
  • Accepted : 2007.09.04
  • Published : 2008.02.28
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Abstract

Silica- or titania-filled poly (vinylidene fluoride-co-hexafluoropropylene)-based polymer electrolytes were prepared by phase inversion technique using N-methyl-2-pyrrolidone and dimethyl acetamide as solvent and water as non-solvent. The polymer electrolytes were adopted to the lithium metal polymer battery using high-capacity cathode $Li[Ni_{0.15}Co_{0.10}Li_{0.20}Mn_{0.55}]O_2$ and lithium metal anode. After the repeated charge-discharge test for the cell, it was proved that the cell adopting the polymer electrolyte based on the phase-inversion membrane containing 40~50 wt% silica showed the highest discharge capacity (180 mAh/g) until 80th cycle and then abrupt capacity fade was just followed. The capacity fade might be due to the deposition of lithium dendrite on the polymer electrolyte, in which the capacity retention was no longer sustainable.

용매 N-methyl-2-pyrrolidone(NMP)과 dimethyl acetamide(DMAc)를 각각 사용하고 물을 비용매로 사용하는 상반전 기법에 의해, 실리카($SiO_2$)와 티타니아($TiO_2$) 나노입자가 각각 충진된 poly(vinylidene fluoride-co-hexafluoropropylene) (PVdF-HFP) 고분자 전해질을 제조하고, 이를 고용량 양극재료인 $Li[Ni_{0.15}Co_{0.10}Li_{0.20}Mn_{0.55}]O_2$를 주성분으로 하는 양전극과 리튬금속 음전극 사이에 채용하는 리튬금속 고분자 2차전지를 제작하여 그 충방전 특성을 조사하였다. 고분자 전해질 제조에 사용한 용매에 상관없이 실리카 충진재의 함량이 40~50 wt%인 상반전막을 고분자 전해질로 적용하였을 때 가장 높은 방전용량(180 mAh/g)을 나타내었으며, 이 경우 대개 80 사이클까지 초기용량의 99% 정도의 지속성을 보이다가 그 이후 급격한 용량 감소를 보였다. 이 용량 감소는 상반전막이 보장하는 용량 유지능력이 더이상 발휘될 수 없는 상태로 고분자 전해질에 리튬 dendrite가 침적되었기 때문이라 생각된다.

Keywords

References

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