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  • 03월 02일 17시 이후 : 초록수정 불가능, 일정확인 및 검색만 가능

제109회 대한화학회 학술발표회, 총회 및 기기전시회 안내 Ab initio study of the sodium intercalation and intermediate phases in Na0.44MnO2

등록일
2012년 2월 16일 15시 23분 02초
접수번호
1039
발표코드
ELEC.P-1270 이곳을 클릭하시면 발표코드에 대한 설명을 보실 수 있습니다.
발표시간
4월 25일 (수요일) 18:00~21:00
발표형식
포스터
발표분야
전기화학
저자 및
공동저자
김희진
KAIST EEWS, Korea
The Na0.44MnO2 structure is a promising cathode material for sodium ion batteries due to a high capacity (~130mAh/g) and good cycle performance. In this work, we present the results of density functional theory (DFT) calculations on the structural and electrochemical properties of Na 0.44 MnO 2 , combined with experiments. Seven intermediate phases and the two-phase reactions among them were found, where the calculated voltage profile agreed well with experiments. We found that the S-shaped tunnel is not empty in the deintercalated Na 0.22 MnO 2 structure, but has a partial occupancy of sodium ions. The new sodium sites were found in a limited sodium composition range (x=0.44~0.55) which is attributed to the electrostatic interactions between sodium ions and manganese atoms. The asymmetric lattice evolution in Na 0.44 MnO 2 as a function of sodium insertion/deinsertion is shown to be due to the Jahn-Teller effects. Based on this interpretation, we suggest that the Cr substitution will reduce the volume change significantly.

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