Lithium ion battery silicon carbide composite anode material and preparation method thereof

A lithium-ion battery, silicon-carbon composite technology, applied in the direction of battery electrodes, circuits, electrical components, etc., can solve the problems of lack, slow structure damage, agglomeration, etc., achieve high safety, improve dispersion, improve first-time efficiency and The effect of cycle stability

Active Publication Date: 2012-08-29
BTR NEW MATERIAL GRP CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
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Problems solved by technology

However, the number of surface atoms, specific surface area and surface energy of nano-silicon will increase rapidly during charging and discharging. There are no adjacent atoms around the surface atoms, and there are many dangling bonds. It has unsaturated properties and is easy to combine with other atoms, so it has great Chemically active, prone to agglomeration during placement and use
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  • Lithium ion battery silicon carbide composite anode material and preparation method thereof
  • Lithium ion battery silicon carbide composite anode material and preparation method thereof
  • Lithium ion battery silicon carbide composite anode material and preparation method thereof

Examples

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preparation example Construction

[0022] The preparation method of the silicon-carbon composite negative electrode material of the lithium ion battery of the present invention uses a cationic dispersant to modify the surface of graphite to obtain a graphite dispersion, and at the same time uses an anionic dispersant to adsorb on the surface of nano-silicon particles to improve the silicon grinding liquid. Dispersion, and ultrasonically disperse the silicon grinding liquid; finally, use the interaction of positive and negative charges to attract each other, and mix the silicon grinding dispersion with the graphite dispersion by slowly dropping, and then adjust it with acid or alkali after mixing evenly The pH value of the entire system to achieve the best dispersion effect, thereby improving the uniformity of the material and improving the cycle performance of the silicon-carbon composite material, specifically including the following steps:

[0023] 1. The preparation of graphite dispersion liquid, add water to...

Embodiment 1

[0053] 1. Dissolve 2 grams of cationic dispersant hexadecyltrimethylammonium chloride in deionized water of 10 parts by mass of cationic dispersant, add solvent ethanol, adjust the pH value of the solution to 5.5, add the graphite core interphase Carbon microspheres MCMB 100g, average particle size 11μm, specific surface area 5.6m 2 / g, tap density 1.46g / cm 3 , rotating speed 2500r / min, stirring for 30min.

[0054] 2. Weigh 288 grams of silicon grinding liquid, the solid content is 11.55%, the average particle size of silicon particles is 180nm, add 0.17 grams of sodium lignosulfonate, ultrasonically disperse for 15 minutes, the frequency is 20KHZ, and the power density is 0.5W / cm 2 , to obtain a silicon grinding dispersion.

[0055] 3. Slowly add the silicon grinding dispersion to the graphite dispersion at a rotational speed of 2500r / min, and then add solvent ethanol to adjust the solid content of the entire dispersion system to 20%, and then adjust the pH of the system to...

Embodiment 2

[0067] 1. Dissolve 2 grams of cationic dispersant polyetherimide in deionized water with 10 parts by mass of cationic dispersant, add solvent ethanol, adjust the pH value of the solution to 5.5, add 100 grams of natural spherical graphite SG, and the average particle size The diameter is 11μm, and the specific surface area is 6.3m 2 / g, tap density 1.57g / cm 3 , rotating speed 1500r / min, stirring for 30min.

[0068] 2. Weigh 288 grams of silicon grinding liquid, the solid content is 11.55%, the average particle size of silicon particles is 150nm, add 0.17 grams of sodium lignosulfonate, ultrasonically disperse for 10 minutes, the frequency is 20KHZ, and the power density is 0.8W / cm 2 , to obtain a silicon grinding dispersion.

[0069]3. Slowly add the silicon grinding dispersion to the graphite dispersion at a rotational speed of 2500r / min, and then add solvent ethanol to adjust the solid content of the entire dispersion system to 20%, and then adjust the pH of the system to ...

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Abstract

The invention discloses a lithium ion battery silicon carbide composite anode material and a preparation method thereof and aims to solve the technical problem of improving the cycling stability of a silicon carbide cathode. The lithium ion battery silicon carbide composite anode material consists of the following components in percentage by mass: 85 to 75 percent of graphite and 15 to 25 percent of silica particles, wherein the nano silica particles are dispersed on a graphite carrier to form a nuclear shell structure and are 5 to 16 mum in granularity. The preparation method comprises the following steps of: preparing a graphite dispersing agent and a silicon grinding dispersing agent; adding the silicon grinding dispersing agent into the graphite dispersing agent; and performing thermal treatment. When the method is compared with the prior art, silicon atoms are dispersed on a graphite atomic nucleus by a cation-anion charge absorption method, so that the silicon atoms can uniformly wrap the surface of the graphite, the dispersity of silicon is effectively improved in a silicon carbide composite material preparing process, the initial efficiency and the cycling stability of the silicon carbide composite anode material are improved, and a battery using the material as an anode material has relatively high safety, multiplying power performance and cycle performance.

Description

technical field [0001] The invention relates to a lithium ion battery negative electrode material and a preparation method thereof, in particular to a silicon-carbon composite material and a preparation method thereof. Background technique [0002] Due to the rapid development and wide application of various portable electronic devices and electric vehicles, there is an urgent need for lithium-ion batteries with high energy and long cycle life. At present, graphite, the main negative electrode material of commercial lithium-ion batteries, has low theoretical capacity (372mAh / g) and poor high-rate charge and discharge performance, which limits the further improvement of lithium-ion battery energy. So far, silicon has the highest theoretical capacity among anode materials. Li and Si form an alloy Li x Si (0<x≤4.4), it is generally believed that at room temperature, the lithium-rich product produced by the alloying of silicon anode and lithium is mainly Li 3.75 Si phase, ...

Claims

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Application Information

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IPC IPC(8): H01M4/587H01M4/38H01M4/1395H01M4/1393
CPCH01M4/366H01M4/386H01M4/587Y02E60/10
Inventor 刘祥岳敏肖翠翠黄友元
Owner BTR NEW MATERIAL GRP CO LTD
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