Acta Phys. -Chim. Sin. ›› 2005, Vol. 21 ›› Issue (07): 725-729.doi: 10.3866/PKU.WHXB20050706

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The Effect of Ti4+, Mg2+ Co-doping on Performance of LiNi0.4Co0.2Mn0.4O2

HUANG You-yuan; ZHOU Heng-hui; CHEN Ji-tao; GAO De-shu; SU Guang-yao   

  1. College of Chemistry, Xiangtan University, Xiangtan 411105; College of Chemistry and Molecular Engineering, Peking University, Beijing 100871
  • Received:2004-11-17 Revised:2005-01-04 Published:2005-07-15
  • Contact: GAO De-shu

Abstract: The effect of co-doping with Ti and Mg ions in LiNi0.4Co0.2Mn0.4O2 on structure and electrochemical performance was investigated by using SEM, XRD, EIS and galvanostatic charge-discharge experiment. The XRD showed that some characteristic peak intensity ratios have significant change. The rate discharge capability and cycle stability of LiNi0.4Co0.2Mn0.4O2 can be improved significantly by a small amount of Ti, Mg ions co-doping (1% molar ratio). AC impedance was used to study the processes of charge-discharge cycle. The result showed that (Ti4+, Mg2+) multiple-ion dopant can evidently suppress the increasing of the electrochemical reaction resistant Rct at 1C & 2C discharge rates. Co-doping of metal ions with diferent valences is a useful method to improve large current discharge capability of the lithium insertion nickel cobalt manganese oxides.

Key words: LiNi0.4Co0.2Mn0.4O2, Layeredstructure, (Ti4+, Mg2+) multiple-ion dopant, Rate-capability, Lithium ion battery