Decoration of lithium spinel oxides using graphene oxides

3^rd International Conference and Exhibition on Materials Science & Engineering

October 06-08, 2014 Hilton San Antonio Airport, USA

Monika Michalska, Bartosz Hamankiewicz, Dominika Ziołkowska, Michał Krajewski, Ludwika Lipinska and Andrzej Czerwinski

Accepted Abstracts: Material Sci Eng

Abstract :

Lithium manganese and lithium titanium oxides of spinel structure are very interesting and promising materials for lithium-ion batteries. Nevertheless, the low electronic and ionic conductivity which lead to poor rate capability still limit its practical usage. In this work we are focus on decoration of lithium manganese oxide (LiMn2O4) - cathode material and lithium titanium oxide (Li4Ti5O12) - anode material using grapheme oxide. The pristine nanocrystalline LiMn2O4 powder was synthesized by modified sol-gel method. The pristine Li4Ti5O12 was synthesized by three-step solid state synthesis. Graphene oxide was prepared by a modified Hummers method. The wet low temperature chemical method was used to modify the LMO and LTO grains using graphene oxide. All the synthesized materials have been characterized by several methods: X-ray powder diffraction (XRD), Raman spectroscopy, Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM). The electrochemical properties were investigated using a three-electrode (SWAGELOK® type) electrochemical cells with Li metal foil as a reference and counter electrode and working electrode made of LMO or LTO. Lithium hexafluorophosphate LiPF6 or lithium bis(trifluoromethanesulfonyl)imide LiTFSI salts dissolved in mixture of EC:DMC=1:1 were used as an electrolytes. The porous polymer Celgard® 2400 was applied as the separator. Every cell was cycled using constant current mode in potential range between 3.5 V and 4.5 V for LMO, and 1 V and 3 V for LTO. Charge-discharge current rates for LMO tests varied from 1 C to 30 C (where 1 C corresponds to current density of 148 mA/g) and for LTO tests varied from 1 C to 10 C (where 1 C corresponds to current density of 175 mA/g).

Biography :

Monika Michalska is a Vice President of NANONET Foundation. She is also Editor-in-Chief on NANONET Newsletter. She is a research assistant at the Institute of Electronic Materials Technology. She specializes in the field of materials science/chemistry/nanotechnology, including in particular the preparation of electrode (for cathode and anode) nanomaterials for lithium ion batteries and supercapacitors using various chemical methods. She also synthesizes composites with ceramic oxide or metallic materials and with carbon coatings: with graphene flakes, graphene oxide and reduced graphene oxide (which are produced in our laboratory).