J Mater Sci Technol ›› 2004, Vol. 20 ›› Issue (01): 46-48.

• Research Articles • Previous Articles     Next Articles

Synthesis and Structure Transformation of Orthorhombic LiMnO2 Cathode Materials by Sol-gel Method

Shixi ZHAO, Hanxing LIU, Qiang LI, Shixi OUYANG   

  1. Department of Chemistry, Tsinghua University, Beijing 100084, China ;State Key Laboratory of Advanced Technology for Materials Synthesis and Processing, Wuhan University of Technology, Wuhan 430070, China
  • Received:1900-01-01 Revised:1900-01-01 Online:2004-01-28 Published:2009-10-10
  • Contact: Shixi ZHAO

Abstract: Orthorhombic LiMnO2 cathode materials were synthesized successfully at lower temperature by sol-gel method. When LiMnO2 precursor prepared by sol-gel method was fired in air, the product was a mixture of spinel structure LiMn2O4 and rock-salt structure Li2MnO3, whereas in argon single-phase orthorhombic LiMnO2 could obtain at the range of 750℃ to 920℃. The substitution of Mn by Zn2+ or Co3+ in LiMnO2 led to the structure of LiMnO2 transiting to α-LiFeO2. The results of electrochemical cycles indicated that the discharged capacity of orthorhombic-LiMnO2 was smaller at the initial stages, then gradually increased with the increasing of cycle number, finally the capacity stabilized to certain value after about 10th cycles. This phenomenon reveals that there is an activation process for orthorhombic LiMnO2 cathode materials during electrochemical cycles, which is a phase transition process from orthorhombic LiMnO2 to tetragonal spinel Li2Mn2O4. The capacity of orthorhombic LiMnO2 synthesized at lower temperature is larger than that synthesized at high temperature.

Key words: Orthorhombic LiMnO2, Synthesis, Structure transformation, Sol-gel method