Vanadium dioxide-graphene compound and its use as lithium ion battery positive electrode material

A lithium-ion battery and graphene composite technology, applied in battery electrodes, secondary batteries, circuits, etc., can solve problems such as poor conductivity and poor cycle performance, and achieve high conductivity, large specific capacity, and excellent high-rate performance.

Active Publication Date: 2014-08-27
YADEA TECH GRP CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0005] The technical problem to be solved by the present invention is to overcome the disadvantages of poor conductivity and poor cycle performance of vanadium dioxide in the prior art, and to provide a vanadium dioxide with high capacity, high rate performance, excellent cycle performance, and can be used as the positive electrode material of lithium ion batteries. Vanadium dioxide-graphene composite

Method used

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  • Vanadium dioxide-graphene compound and its use as lithium ion battery positive electrode material
  • Vanadium dioxide-graphene compound and its use as lithium ion battery positive electrode material
  • Vanadium dioxide-graphene compound and its use as lithium ion battery positive electrode material

Examples

Experimental program
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Effect test

Embodiment 1

[0038] A vanadium dioxide-graphene composite, which is prepared through the following steps:

[0039] (1) Mix 1800mg of vanadium pentoxide and 400mg of graphene oxide (the mass ratio of the two is 4.5:1), disperse them into 200mL of water, then seal them in a hydrothermal kettle, and react at 180±5°C for 12 hours about;

[0040] (2) Add 2-10mL (35wt%) hydrazine hydrate to the system after step (1), and carry out the reduction reaction at 80±2°C for about 5 hours;

[0041] (3) Freeze-dry at -40°C to obtain a solid product, which is a vanadium dioxide-graphene composite.

[0042] Characterize the morphology of the obtained vanadium dioxide-graphene composite, the results can be found in figure 1 . The vanadium dioxide-graphene composite is composed of vanadium dioxide-graphene composite strips with an average length of 1-100 μm, a width of 20-500 nm, and a thickness of 1-50 nm, with a specific surface area of ​​420 m 2 / g.

[0043] Characterize the structure of the vanadiu...

Embodiment 2

[0046] Embodiment 2 provides a vanadium dioxide-graphene composite, the preparation method of which is basically the same as that of Embodiment 1, except that the mass ratio of the raw material vanadium oxide to graphene oxide is 3:1. The vanadium dioxide-graphene composite is made into a working electrode according to the method provided by the present invention and the corresponding electrochemical performance test is carried out. The results are as follows: the first Coulombic efficiency is more than 90%, and when charging and discharging at 1C, the stable specific capacity is 390mAh / g; when charging and discharging at 20C, the stable specific capacity is 295mAh / g; when charging and discharging at 200C, the stable specific capacity is 204mAh / g; when charging and discharging at the above rate, the capacity can be maintained after 1400 repeated charging and discharging More than 90% of the initial capacity.

Embodiment 3

[0048] This example provides a vanadium dioxide-graphene composite, the preparation method of which is basically the same as in Example 1, except that the mass ratio of vanadium oxide and graphene oxide as raw materials is 2:1.

[0049] The vanadium dioxide-graphene composite is made into a working electrode according to the method provided by the present invention and the corresponding electrical performance test is carried out. The results are as follows: the first coulombic efficiency is 92%, and when charging and discharging at 1C, the stable specific capacity is 370mAh / g; when charging and discharging at 20C, the stable specific capacity is 284mAh / g; when charging and discharging at 200C, the stable specific capacity is 194mAh / g; and when charging and discharging at the above rate, the capacity can be maintained after 1400 repeated charging and discharging More than 92% of the original capacity.

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Abstract

The invention relates to a vanadium dioxide-graphene compound and its use as a lithium ion battery positive electrode material. The compound is composed of vanadium dioxide-graphene compound bands or sheets, and the specific surface area of the compound is 20-800m<2> / g; vanadium dioxide in the compound is VO2(B),C2 / m structure crystals; graphene on the compound bands or sheets has a porous structure; and when the compound is used as the lithium ion battery positive electrode material, the charge and discharge platform is 2.5V, and the specific capacity of a battery using the positive electrode material is higher than 400mAh / g and 200mAh / g after the battery is repeated charged and discharged at 1C and 200C 110 times. The compound has the advantages of high conductivity, low dimensions, super excellent high-magnification performances and good cycle stability, is an ideal lithium ion battery positive electrode material; and additionally, the compound is prepared through a technology having the advantages of high repeatability, simple process and less time consumption by using cheap raw materials, and is suitable for industrial production.

Description

technical field [0001] The invention relates to a new vanadium dioxide-graphene compound which can be used as lithium ion electron cathode material. Background technique [0002] With the continuous breakthrough of electronic technology and the international attention to energy and environmental protection, new secondary energy is developing rapidly and vigorously worldwide. Among them, lithium-ion secondary batteries have become the preferred power source for portable electronic appliances such as cameras, mobile phones, and notebook computers due to their excellent characteristics, and are also ideal potential power systems for future space technology and high-end energy storage systems. Lithium-ion secondary batteries are mainly composed of positive electrodes, negative electrodes, separators and electrolytes, and have high charge storage density, fast charge and discharge characteristics, good charge and discharge efficiency and high cycle life, and low-cost lithium-ion ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M4/48H01M4/583
CPCH01M4/362H01M4/48H01M10/0525Y02E60/10
Inventor 张慧娟
Owner YADEA TECH GRP CO LTD
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