Acta Phys. -Chim. Sin. ›› 2004, Vol. 20 ›› Issue (03): 233-236.doi: 10.3866/PKU.WHXB20040303

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The Structural Stability of S-M (M=Al, Co) Co-doped Spinel LiMn2O4 Cathode Materials

Zhao Shi-Xi;Min Xin-Min;Liu Han-Xing;Li Qiang;Ouyang Shi-Xi   

  1. Department of Chemistry, Tsinghua University, Beijing　100084; 2State Key Laboratory of Advanced Technology for Materials Synthesis and Processing, Wuhan University of Technology, Wuhan　430070
  • Received:2003-07-25 Revised:2003-10-21 Published:2004-03-15
  • Contact: Zhao Shi-Xi E-mail:zhaoshixi@tsinghua.org.cn

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Abstract: The structural stability of S-Al, S-Co co-doped spinel structure lithium manganese oxide was investigated with self-consistent-charge discrete variational(SCC-DV-Xα) method of quantum chemistry. The calculated results show that the average covalences of S-Al co-doped spinel [LixMn3Al3O20S6]n－ and S-Co co-doped spinel [LixMn3Co3O20S6]n－ both are stronger than that of undoped spinel [LixMn6O26]n－, and approach to that of MnO2, the charge of Mn in [LixMn3Al3O20S6]n－ also approaches to that in MnO2 model [Mn6O26]28－； the order of the charge density of Mn atom in various model is as fellows: MnO2≈[LixMn3Al3O20S6]n－≈[LixMn3Co3O20S6]n－< [LixMn6O26]n－. It is said that the state of Mn in [LixMn3Co3O20S6]n－ and[LixMn3Al3O20S6]n－ is similar to that in MnO2. These results revealed the reason that structural stability of S-Al, S-Co co-doped spinel structure lithium manganese oxide was enhanced during electrochemical cycle.

Key words: LiMn2O4 cathode materials, S-M (M=Al, Co) co-doped, Self-consistent-charge discrete variational (SCC-DV-Xα ) method