Graphene nanometer sheet-cobaltous oxide composite negative electrode material of lithium ion battery and preparation method thereof

Abstract

The invention relates to a graphene nanometer sheet-cobaltous oxide composite negative electrode material of a lithium ion battery and a preparation method thereof, and belongs to the technical field of batteries. The negative electrode material consists of graphene nanometer sheets and cobaltous oxide, wherein the graphene nanometer sheets are distributed on cobaltous oxide particles in a staggering way; the mass fraction of the graphene nanometer sheets is 5 to 90 percent; the thickness of the graphene nanometer sheets is 1 to 50 nanometers; and the particle size of the cobaltous oxide is 10 to 500 nanometers. The preparation method comprises the following steps: dispersing graphite oxide in alcohol-water solution or aqueous solution with ultrasound or stirring; adding cobalt salt, alkali and a reducing agent into the mixture and pouring the mixture into a hydrothermal kettle after stirring; performing further sealing and synchronous hydrothermal reaction, washing, filtering and drying to obtain a graphene nanometer sheet-cobaltous oxide composite; and processing the graphene nanometer sheet-cobaltous oxide composite in the protective atmosphere to obtain the graphene nanometer sheet-cobaltous oxide composite negative electrode material. In the invention, when the material is charged or discharged by a current of 200mA / g, the reversible specific capacity of the material can be stabilized in a range of over 900mAh / g.

Description

technical field [0001] The invention relates to an electrode material in the field of battery technology and a preparation method thereof, in particular to a graphene nanosheet-cobaltous oxide composite negative electrode material for a lithium ion battery and a preparation method thereof. Background technique [0002] Since Nature 2000, 407, 496 reported the application of transition metal oxides as anode materials for lithium-ion batteries, many researchers have conducted in-depth studies on them. As a lithium-ion battery anode material, the theoretical specific capacity of CoO is as high as 715mAh / g, about twice that of graphitized carbon materials. Although the reported CoO has a high specific capacity, its initial efficiency and cycle performance are poor, as reported in the literature J. Power Sources 2002, 109, 142, and its reversible capacity after 20 cycles is only 270mAh / g. In addition, although the specific capacity and performance of CoO reported in the document...

AI Technical Summary

Problems solved by technology

Although the reported CoO has a high specific capacity, its initial efficiency and cycle performance are poor, as reported in the literature J. Power Sources 2002, 109, 142, and its reversible capacity after 20 cycles is only 270mAh / g

In addition, although the specific capacity and performance of CoO reported in the document J.Electrochemical Soc.2008, 155 (12), A903 and J.Power Sources 2005, 146, 482 are all good, the charge and discharge current used in the test is low (100mA / g)

Images