Acta Phys. -Chim. Sin. ›› 2013, Vol. 29 ›› Issue (04): 763-769.doi: 10.3866/PKU.WHXB201302211

• ELECTROCHEMISTRY AND NEW ENERGY • Previous Articles     Next Articles

Synthesis and Electrochemical Characterization of Ge4+, Sn4+ Doped Spinel LiMn2O4

XIONG Li-Long, XU You-Long, TAO Tao   

  1. Electronic Materials Research Laboratory, Key Laboratory of the Ministry of Education, Xi’an Jiaotong University, Xi’an 710049, P. R. China;International Center for Dielectric Research, Xi’an Jiaotong University, Xi’an 710049, P. R. China
  • Received:2012-12-03 Revised:2013-02-19 Published:2013-03-25
  • Supported by:

    The project was supported by the National Natural Science Foundation of China (21203145).

Abstract:

Spinel LiMn2O4 materials doped with tetravalent cations Ge4+ and Sn4+ were synthesized through solid-state reaction. Analysis of the materials by X-ray diffraction (XRD) and scanning electron microscopy (SEM) suggested that Ge4+ ions occupied octahedral sites by substituting Mn4+ ions in the spinel structure to form the solid solution LiMn2-xGexO4 (x=0.02, 0.04, 0.06), while Sn4+ ions were present at the surface of the spinel LiMn2O4 as SnO2. The substitution of Mn4+ with Ge4+ could suppress the long-range ordering of the Li+ ions in the spinel LiMn2O4, enhancing its stability. SnO2 on the surface of LiMn2O4 could reduce the acidity of the liquid electrolyte, suppressing acid etching of the LiMn2O4 active material. Galvanostatic charge/ discharge tests showed that both Ge4+ and Sn4+-modified spinel LiMn2O4 materials exhibited significantly higher capacity retention than LiMn2O4. The increased capacity retention should benefit the application of spinel LiMn2O4 as a cathode material for lithium-ion batteries.

Key words: Spinel LiMn2O4, Ge4+ doping, Sn4+ doping, Solid-state reaction, Cycleability

MSC2000: 

  • O646