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  • 08월 18일 17시 이후 : 초록수정 불가능, 일정확인 및 검색만 가능

제108회 대한화학회 학술발표회, 총회 및 기기전시회 안내 In situ XRD Studies of Mixed Cathode Materials for Li-ion Batteries

2011년 7월 27일 15시 26분 35초
ELEC-3 이곳을 클릭하시면 발표코드에 대한 설명을 보실 수 있습니다.
금 10시 : 10분
전기화학 - Energy related materials & Electrochemistry
저자 및
국민대학교 신소재공학과, Korea
The present commercial battery is based on a layered LiCoO2 cathode and a graphitized carbon anode. LiCoO2 is expensive but it has the advantage being easily manufactured in a reproducible manner. Other low cost layered compounds such as LiNiO2, LiNi0.85Co0.15O2 or cubic spinels such as LiMn2O4 have been studied as alternatives. However, these materials suffer from poor cycle life or thermal stability problems. Recently, some studies on mixing two different types of cathode materials to make a composite cathode have been reported, which were aimed at reducing cost and improving self-discharge. Numata et al. reported that when stored in a sealed can together with electrolyte at 80 ºC for 10 days, the concentrations of both HF and Mn2+ were lower in the can containing LiMn2O4 blended with LiNi0.8Co0.2O2 than that containing LiMn2O4 only. That reports clearly showed that this blending technique can prevent the decline in capacity caused by cycling or storage at elevated temperatures. However, not much work has been reported on the charge-discharge characteristics and phase transitions for these composite cathodes. In this presentation, we will report our in situ x-ray diffraction studies on this mixed composite cathode material during charge-discharge cycling. The structural changes of each component in the LiMn2O4-LiNi1/3Co1/3Mn1/3O2 composite cathode are studied separately in the half cell first and then compared with the composite cathode made by mixing spinel LiMn2O4 and layered LiNi1/3Co1/3Mn1/3O2 in 1:1 wt%. At the early stage of charge, the lithium extraction and structural changes take place in the LiNi1/3Co1/3Mn1/3O2 component only. When the cell voltage reaches at ~4.0 V vs. Li/Li+, lithium extraction from the spinel LiMn2O4 component starts and becomes the major contributor for the cell capacity due to the higher rate capability in addition to the voltage threshold of LiMn2O4. More detailed discussion will be presented at the meeting.