LiMn2O4/graphene oxide as a cathode material for lithium ion battery
|Monika Michalska 1, Dominika Ziółkowska 2, Jacek Jasiński 3, Ludwika Lipińska 1|
1. Institute of Electronic Materials Technology (ITME), Wólczyńska, Warsaw 01-919, Poland
Lithium manganese oxide (LMO, LiMn2O4) of spinel structure is very promising as a cathode material for secondary lithium ion batteries. This compound has several advantages like: low cost and easy preparation, non-toxicity, high discharge potential (4V vs. lithium metal), a satisfactory practical capacity (120 mAh/g), high-energy density and low self-discharge. One of the drawbacks of lithium manganese oxide is its modest electronic conductivity. There are several ways of enhance it: i) introducing metal particles onto LiMn2O4 internal surfaces, ii) coating the spinel particles by conducting polymers, iii) the most popular - using carbon either as thin layers or mixing as-synthesized LiMn2O4 with carbon species.
In our studies we used graphene oxide (GO) as a carbon species. The pristine nanocrystalline LiMn2O4 powder was synthesized by modified sol-gel method [1-3]. Graphene oxide was prepared by a modified Hummers method [4,5]. The wet low temperature chemical method was used to modify the LMO grains using graphene oxide.
The structure and morphology of the synthesised powders were characterized by: X-ray powder diffraction (XRD), Raman spectroscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS). The electrochemical charge-discharge tests were performed in three electrode cells with LiMn2O4/n-GO as working and lithium as a reference and counter electrode. A lithium hexafluorophosphate LiPF6 in a mixture of ethylene and dimethyl carbonates (1:1) was used as an electrolyte. The working and counter electrode was detached by Celgard 2400 separator. Every cell was cycled using constant current mode in potential range between 3.5 V and 4.5 V Charge – discharge current rates for LMO/n-GO tests varied from 1 C to 30 C, where 1 C corresponds to current density of 148 mA/g.
This work was supported by The National Centre for Research and Development through the research grant PBS1 (contract no. PBS1/A1/4/2012).
 B. Hamankiewicz, M. Michalska, M. Krajewski, D. Ziolkowska, L. Lipińska, M. Kamińska, A. Czerwinski, The effect of electrode thickness on electrochemical performance of LiMn2O4 cathode synthesized by modified sol-gel method, Solid State Ionics 262 (2014) 9-13.
 M. Michalska, L. Lipińska, M. Mirkowska, M. Aksienionek, R. Diduszko, M. Wasiucionek, Solid State Ionics 188 (2011) 160.
 Monika Michalska, Ludwika Lipińska, Ryszard Diduszko, Marta Mazurkiewicz, Artur Małolepszy, Leszek Stobinski, Krzysztof J. Kurzydłowski, Physica Status Solidi C 8 No. 7–8 (2011) 2538.
. W. S. Hummers, R. E. Offeman, J. Am. Chem. Soc., 80 (6) (1958) 1339.
 Ł Majchrzycki, M. Michalska, M. Walkowiak, Z. Wiliński, L. Lipińska, Polish Journal of Chemical Technology 15 3 (2013) 15.
Presentation: Oral at Nano PL 2014, Symposium A, by Monika Michalska
See On-line Journal of Nano PL 2014
Submitted: 2014-04-20 19:49 Revised: 2014-09-28 20:48