Lithium ion battery silicon/carbon negative electrode composite material and preparation method thereof

A technology of lithium ion battery and composite material, applied in the field of lithium ion battery silicon/carbon negative electrode composite material and its preparation, can solve problems such as poor electronic conductivity and slow lithium ion diffusion, achieve high specific capacity, improve diffusion performance, and increase rate Excellent performance

Active Publication Date: 2019-05-14
XINYANG NORMAL UNIVERSITY
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  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0007] In order to overcome the three main problems of the volume expansion of silicon materials during the charge and discharge process, the slow diffusion of lithium ions inside the silicon materials, and the poor electronic conductivity of silicon, the discharge specific capacity of silicon-based negative electrode materials, the charge-discharge cycle stability, As well as the rate performance, the invention provides a silicon / carbon negative electrode composite material for a lithium ion battery and a preparation method thereof

Method used

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  • Lithium ion battery silicon/carbon negative electrode composite material and preparation method thereof
  • Lithium ion battery silicon/carbon negative electrode composite material and preparation method thereof
  • Lithium ion battery silicon/carbon negative electrode composite material and preparation method thereof

Examples

Experimental program
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Effect test

Embodiment 1

[0033] (1) Using perlite as raw material, put perlite in a 100ml agate ball mill jar, add 50g of agate balls with a diameter of 20mm, 40g of agate balls with a diameter of 10mm, and 10g of agate balls with a diameter of 5mm. Among them, the mass ratio of agate balls to perlite is 20:1, the ball milling speed is 450 rpm, and the ball milling takes 48 hours to obtain micron-sized perlite particles.

[0034] (2) at 300o C preheat for 25 min, then at 1100 o C heating for 10s, and finally quickly transfer the material from the high temperature environment to 25 o Cool at room temperature around C, and then use 4M hydrochloric acid at 80 o C for 24 hours, washed, filtered, and dried to obtain a porous silica material.

[0035] (3) Mix 10g of porous silicon dioxide with 10g of magnesium powder at 700 o Under the atmosphere of C and Ar, the magnesothermic reduction reaction was carried out, and then treated with 1 M hydrochloric acid at 80 o C was treated for 4 hours to obtain a p...

Embodiment 2

[0044] Step (1-3) is the same as the preparation process of Example 1. In step (4), 3 g of porous silicon material is mixed with 3.5 g of cobalt acetate and 7.6 g of dicyandiamide, and mixed at 700 o Baking is carried out under the atmosphere of C and Ar to obtain the silicon / carbon negative electrode composite material in which the cobalt silicide connects the carbon nanotube and the porous silicon. In the composite material, the porous silicon material accounts for 43.2% of the total mass of the composite material wt %. The electrochemical performance of the composite material is shown in Table 1.

Embodiment 3

[0046] Step (1-3) is the same as the preparation process of Example 1. In step (4), 3 g of porous silicon material, 3.2 g of ferrous oxalate and 7.6 g of urea are mixed uniformly, and mixed at 700 o Baking is carried out under the atmosphere of C and Ar to obtain the silicon / carbon negative electrode composite material in which iron silicide is connected with carbon nanotubes and porous silicon. In the composite material, the porous silicon material accounts for 40.6% of the total mass of the composite material wt %. The electrochemical performance of the composite material is shown in Table 1.

[0047] Table 1. The charging and discharging performance of silicon / carbon negative electrode composite material in the embodiment

[0048]

[0049] It can be seen from the above table that the silicon / carbon negative electrode composite material in the present invention has a high discharge specific capacity and excellent cycle stability, and the capacity retention rate after ...

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Abstract

The invention discloses a lithium ion battery silicon / carbon negative electrode composite material. The lithium ion battery silicon / carbon negative electrode composite material is of a core shell structure, wherein a core is porous-structure silicon particle, a shell layer is a zigzagging carbon nanotube cluster having a large amount of gaps, and interfaces of the core and the shell layer are connected by a metal silicide. In the lithium ion battery silicon / carbon negative electrode composite material, the volume expansion of silicon during the charge-discharge process is remarkably reduced byporosity of the silicon particle, and the diffusion performance of lithium ions in the silicon is improved; with high conductivity of the carbon nanotube cluster, the defect of low conductivity of the silicon is overcome, meanwhile, the carbon nanotube cluster is used as a flexible external buffer layer, the volume expansion of the silicon is further reduced; and the metal silicide is used as a compact connection point, an electron transmission passage is built between the silicon and the carbon nanotube, and the carbon nanotube can be prevented from falling off during the charge-discharge process. The novel-structure silicon / carbon negative electrode composite material provided by the invention has the advantages of high specific capacity, good cycle property, excellent rate performanceand the like in application of a lithium ion battery and is low in fabrication cost and simple in method, and industrial production is easily achieved.

Description

technical field [0001] The invention relates to the technical field of negative electrode materials for lithium ion batteries, in particular to a silicon / carbon negative electrode composite material with a novel structure for lithium ion batteries and a preparation method thereof. Background technique [0002] Lithium-ion batteries have the advantages of high energy density, high working voltage, fast charging speed, long cycle life, environmental friendliness, safety and stability. They are currently the most promising green energy storage power sources and are widely used in mobile electronic devices and electric vehicles. and electronic fields. However, with the development needs of miniaturization, high energy, and portability of electronic appliances and the popularization and application of new energy electric vehicles, the requirements for various technical indicators of lithium-ion batteries are getting higher and higher. [0003] At present, the commonly used anode...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M4/36H01M4/38H01M4/62H01M10/0525
CPCY02E60/10
Inventor 陈明孙海斌许军旗王红军朱建军田永尚
Owner XINYANG NORMAL UNIVERSITY
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