Spinel-Type Lithium Titanium Oxide/Graphene Composite and Method of Preparing the Same

Abstract

A spinel-type lithium titanium oxide / graphene composite and a method of preparing the same are provided. The method can be useful in simplifying a manufacturing process and shortening a manufacturing time using microwave associated solvothermal reaction and post heat treatment, and the spinel-type lithium titanium oxide / graphene composite may have high electrochemical performances due to its excellent capacity and rate capability and long lifespan, and thus be used as an electrode material of the lithium secondary battery.

Description

CROSS-REFERENCE TO RELATED APPLICATION[0001]This application claims priority to and the benefit of Korean Patent Application No. 2010-0106929, filed Oct. 29, 2010, the disclosure of which is incorporated herein by reference in its entirety.BACKGROUND[0002]1. Field of the Invention[0003]The present invention relates to a spinel-type lithium titanium oxide (Li4Ti5O12) / reduced graphite oxide (graphene) composite and a method of preparing the same, and more particularly, to a method of preparing a spinel lithium titanium oxide / graphene composite having excellent electrochemical properties capable of simplifying a manufacturing process and shortening a manufacturing time using microwave associated solvothermal reaction and post heat treatment.[0004]2. Discussion of Related Art[0005]Graphene is a carbon structure composed of a two-dimensional (2-D) nanosheet single layer in which sp2 carbon atoms are formed into a hexagonal honeycomb lattice. Since graphene was separated from graphite usi...

AI Technical Summary

Benefits of technology

[0010]The present invention is directed to providing a method capable of manufacturing a lithium titanium oxide / graphene composite without performing a subsequent process of removing oxygen functional groups from a surface of graphene oxide and uniformly forming a transition metal oxide on a surface of graphene within a short period of time when the lithium titanium oxide / graphene composite is synthesized using a graphite oxide precursor.

[0011]Also, the present invention is directed to providing an anode material for lithium secondary batteries composed of the lithium titanium oxide / graphene composite to give high capacity and rate capability, and a lithium secondary battery including an electrode composed of the anode material.

Problems solved by technology

However, graphene is not easily peeled even when it is in a solution phase because of the van der Waals's interaction between graphene layers due to the presence of sp2 carbon bonds on a surface of the graphene.

Therefore, when a complex material with a transition metal oxide is synthesized in a solution phase using graphene as a precursor, it is difficult to use a high specific surface area of single layer graphene and to form a uniform complex structure, which serves as a factor preventing the use of the transition metal oxide.

However, since the various oxygen functional groups introduced into the surface of the graphene oxide through an oxidation process are generated by partial breakup of sp2 bonds of graphene, the electric conductivity may be degraded.

However, conventional Li4Ti5O12 having a spinel structure is difficult to manufacture on a nanosized scale due to its limits in manufacturing processes, and shows poor capacity and rate capability as the lithium battery anode material because of its poor conductivity.

In addition, since a large amount of time (for example, 24 hours) is required to synthesize Li4Ti5O12, many problems should be solved in advance for it to be applied to the lithium secondary battery.

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