物理化学学报 >> 2004, Vol. 20 >> Issue (03): 233-236.doi: 10.3866/PKU.WHXB20040303

研究论文 上一篇    下一篇

S-M(M=Al, Co)复合掺杂LiMn2O4的结构稳定性

赵世玺;闵新民;刘韩星;李强;欧阳世翕   

  1. 清华大学化学系,北京 100084;武汉理工大学材料复合新技术国家重点实验室,武汉 430070
  • 收稿日期:2003-07-25 修回日期:2003-10-21 发布日期:2004-03-15
  • 通讯作者: 赵世玺 E-mail:zhaoshixi@tsinghua.org.cn

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

摘要: 应用量子化学电荷自洽离散变分Xα(SCC-DV-Xα)方法,研究了S-Al、S-Co复合掺杂增强尖晶石结构锂锰氧化物稳定性的作用机制.计算结果表明, S-Al复合掺杂锂锰尖晶石和S-Co复合掺杂锂锰尖晶石中的共价键强度均比未掺杂尖晶石LiMn2O4中的强,且与MnO2中的共价键强度相近; S-Al, S-Co复合掺杂尖晶石中Mn的电荷也与MnO2模型[Mn6O26]28-中十分接近. Mn原子的电荷密度次序是MnO2≈掺硫铝后锰锂尖晶石≈掺硫钴后的锂锰尖晶石< 锰锂尖晶石.即[LixMn3Co3O20S6]n-和[LixMn3Al3O20S6]n-中Mn的状态与MnO2中的Mn相似.上述结果揭示了S和非Jahn-Teller效应阳离子(Al3+,Co3+)复合掺杂尖晶石结构锂锰氧化物在电化学过程中不会发生Jahn-Teller畸变的内在原因.

关键词: LiMn2O4正极材料, S-M(M=Al, Co)复合掺杂, 电荷自洽离散变分Xα(SCC-DV-Xα)方法

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