Preparation method of rate-type lithium ion battery silicon composite oxide material

A technology of lithium-ion batteries and composite oxides, applied in battery electrodes, secondary batteries, electrochemical generators, etc., can solve the problems of inability to charge and discharge large currents, difficulty in making breakthroughs, small self-discharge, etc., and achieve the reduction of irreversible lithium The generation of oxygen compounds, the improvement of the first charge and discharge efficiency, and the effect of excellent rate performance

Inactive Publication Date: 2020-03-27
HEFEI GUOXUAN HIGH TECH POWER ENERGY
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Problems solved by technology

[0002] Compared with other types of secondary batteries, lithium-ion batteries have the advantages of higher energy density, longer cycle life, and smaller self-discharge. The field has a very wide range of applications; with the development of science and technology, electronic equipment has put forward higher requirements for battery energy density and power density. The traditional lithium-ion battery negative electrode material is mainly graphite, and its theoretical capacity is 372mAh / g. In practical applications The capacity of graphite can exceed 360mAh / g, which has basically reached the theoretical limit, and it is difficult to make a breakthrough from the perspective of technology
[0003] Compared with graphite materials, silicon is currently the material with the highest theoretical capacity among the anode materials of lithium-ion batteries. Silicon can form lithium-silicon alloy Li3.75Si with lithium ions, and the theoretical capacity is as high as 3752mAh / g, which is basically equivalent to ten times that of graphite materials. times, so the application of silicon materials can greatly increase the energy density of lithium-ion batteries; however, silicon materials face two problems in practical applications: one is that when lithium ions form lithium-silicon alloys with silicon, the volume will expand to the original 3 times, a huge internal stress is formed, which makes the silicon negative electrode detach from the current collector, causing the battery to fail; second, silicon is a semiconductor material with a much lower conductivity than graphite. Using silicon as the battery negative electrode material will cause battery internal The resistance is too large to charge and discharge with high current
[0004] In view of the above problems, the method of compounding silicon and carbon materials is currently used to alleviate the expansion of silicon, but the effect is limited. On the other hand, although the capacity of silicon oxide (SiOX) (about 1500mAh / g) is smaller than that of silicon There are many, but it is several times higher than the carbon-based negative electrode capacity (about 360mAh / g), and has a structure in which silicon nanocrystals are uniformly dispersed in a silicon dioxide matrix, which has gradually become a research hotspot

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  • Preparation method of rate-type lithium ion battery silicon composite oxide material
  • Preparation method of rate-type lithium ion battery silicon composite oxide material
  • Preparation method of rate-type lithium ion battery silicon composite oxide material

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preparation example Construction

[0024] The preparation method of the rate type lithium ion battery silicon composite oxide material according to the present invention comprises the following steps,

[0025] (1) Dispersion: Add 0.75-10g surfactant to 10-100mL deionized water, ultrasonically disperse for 1-2h to form a uniform mixture, then add 1.2-7g carbon nanotubes to the uniform mixture, ultrasonically disperse for 2- After 3h, a uniform carbon nanotube dispersion is formed; wherein, the surfactant is one of sodium dodecylbenzenesulfonate, sodium octadecyl sulfate, quaternary ammonium compound, lecithin, fatty acid glyceride ;

[0026] (2) Coating: add 5-10mL carbon nanotube dispersion liquid to 50-500mL ethanol solution, ultrasonically disperse for 1 hour, then add 2-20mL concentrated ammonia water, continue to stir to form a uniform solution, then add 5-20mL drop by drop to a concentration of 80% tetraethyl orthosilicate, stirred and reacted at room temperature for 0.5-10h, washed with deionized water a...

Embodiment 1

[0032] (1) 0.75g of sodium octadecyl sulfate is added to 50ml of deionized water, and a 300W supersonic dispersing machine with a power of 2h is used to form a homogeneous solution, and then 1.3g of carbon nanotubes are added to the mixed solution containing the surfactant. A 200W ultrasonic disperser was used to obtain a uniform carbon nanotube dispersion after ultrasonication for 3 hours;

[0033] (2) Take 5mL of the carbon nanotube dispersion in step (1), add it into 80mL of 30% ethanol solution, ultrasonically disperse it for 1h, add 5mL of 25% ammonia water into the solution, stir it evenly, and use dropwise Slowly add 5 mL of tetraethyl orthosilicate with a concentration of 80% dropwise into the tube, stir and react at room temperature for 2 h, after the reaction is completed, wash twice with deionized water and dry in a blast drying oven to obtain silica-coated carbon nanotubes;

[0034] (3) Take 0.15 g of silicon dioxide-coated carbon nanotubes prepared in step (2), u...

Embodiment 2

[0037](1) Add 1.1g of sodium dodecylbenzene sulfonate to 40mL of deionized water, use a power 250W ultrasonic disperser to sonicate for 2 hours to form a uniform solution, and then add 1.2g of carbon nanotubes to the mixed solution containing surfactant , using a power 300W ultrasonic disperser to obtain a uniform carbon nanotube dispersion after ultrasonication for 3 hours;

[0038] (2) Take 9ml of carbon nanotube dispersion and add it to 100mL of 30% ethanol solution, ultrasonically disperse for 100min, add 8mL of 25% ammonia water to the solution, stir evenly, and slowly add 7mL of concentration with a dropper It is 80% tetraethyl orthosilicate, stirred and reacted at room temperature for 6 hours, after the reaction is finished, washed with deionized water for 3 times, and then dried in a blast drying oven to obtain carbon nanotubes coated with silicon dioxide.

[0039] (3) Take 0.12 g of the silicon dioxide-coated carbon nanotubes prepared in step 2, use acetylene as the c...

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Abstract

The invention discloses a preparation method of a rate-type lithium ion battery silicon composite oxide material, which comprises the following steps: (1) dispersion: preparing a carbon nanotube dispersion liquid from a surfactant and carbon nanotubes; (2) coating: adding tetraethoxysilane into the carbon nanotube dispersion liquid prepared in the step (1), stirring for reaction at room temperature, and drying to obtain a silicon dioxide coated carbon nanotube; (3) chemical deposition: preparing a carbon-coated silicon dioxide carbon nanotube from the silicon dioxide carbon nanotube obtained in the step (2) by adopting a chemical deposition method; and (4) gas-phase reaction: grinding the carbon-coated silicon dioxide carbon nanotube prepared in the step (3) and magnesium powder in proportion, heating, keeping constant temperature, cooling to room temperature, pickling, washing and drying to obtain the rate-type lithium ion battery silicon composite oxide material. The silicon composite oxide material prepared by the method has excellent rate capability and cycle performance, and the preparation process is simple and practical.

Description

technical field [0001] The invention belongs to the field of lithium-ion battery production, and in particular relates to a method for preparing a silicon composite oxide material for a rate-type lithium-ion battery. Background technique [0002] Compared with other types of secondary batteries, lithium-ion batteries have the advantages of higher energy density, longer cycle life, and smaller self-discharge. The field has a very wide range of applications; with the development of science and technology, electronic equipment has put forward higher requirements for battery energy density and power density. The traditional lithium-ion battery negative electrode material is mainly graphite, and its theoretical capacity is 372mAh / g. In practical applications The capacity of graphite can exceed 360mAh / g, which has basically reached the theoretical limit, and it is difficult to make a breakthrough from the perspective of technology. [0003] Compared with graphite materials, silic...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M4/36H01M4/38H01M4/62H01M10/0525
CPCH01M4/362H01M4/386H01M4/625H01M10/0525H01M2004/027Y02E60/10
Inventor 张二冬李道聪夏昕闵长青张峥
Owner HEFEI GUOXUAN HIGH TECH POWER ENERGY
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