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Structural and electrochemical studies on LiMn2O4 cathode material for LIBs coated with ceramic oxides
|Monika Michalska 1, Bartosz Hamankiewicz 2, Dominika Ziółkowska 3, Michał Krajewski 2, Mariusz Andrzejczuk 4, Ludwika Lipińska 1, Andrzej Czerwiński 2|
1. Institute of Electronic Materials Technology (ITME), Warszawa 01919, Poland
Spinel structured lithium manganese oxide (LiMn2O4) is one of the promising cathode material for transportation and large scale batteries due to its low cost and easy preparation, environmental friendliness, high discharge potential (4V vs. Li/Li+) and good safety compared with the lithium cobalt LiCoO2 or lithium nickel LiNiO2 oxides. Hovewer the LiMn2O4 electrodes at the 4V potential (vs. Li/Li+) region suffers from capacity fading during charge-discharge cycles, especially at elevated temperature (50-60°C), which limits the application in commercial lithium-ion batteries. The capacity loss could be attributed to three main factors: (1) dissolution of manganese Mn2+ ions; (2) Jahn-Teller (J-T) distortion effect; (3) decomposition of organic solvents in electrolyte. Recently, several investigations have been proposed to resolve this complicated problem including metal doping at Mn-sites (Fe, Ni, Cr) and surface coating with metal or ceramic oxides. Finally, it should to improve the capacity retention and minimize the surface area of LiMn2O4 contacting with the electrolyte.
In our current work, we investigated and compared the electrochemical performance of LiMn2O4 coated by various ceramic oxides. The low temperature chemical synthesis (LTCS) was used to modify the surface grains of LMO.
Firstly, pure stoichiometric nanopowder of LiMn2O4 was prepared by modified sol-gel method using lithium and manganese salts. Secondly, we used LTCS for the surface modification by ceramic oxides (like i.e. La2O3, CeO2, SiO2) of LMO spinel.
X-ray powder diffraction (XRD) and Raman spectroscopy were used to characterize the crystal structures of all samples. The particle size and morphology were observed by: SEM, HRSEM, TEM. Also the electrochemical tests were performed.
This work was :by The National Centre for Research and Development through the research grant PBS1 (contract no. PBS1/A1/4/2012). M. Michalska would like to thank for the scholarship awarded by the Mazovia Voivodeship Office through the Scientific Potential for the Economy of Mazovia PhD Program, co-funded by the European Social Fund.
Presentation: Poster at Nano and Advanced Materials Workshop and Fair, by Monika Michalska
See On-line Journal of Nano and Advanced Materials Workshop and Fair
Submitted: 2013-07-14 15:10 Revised: 2013-08-16 23:55