Lithium ion battery silicon oxide and carbon composite negative pole material and preparation method thereof

A lithium ion battery, silicon oxide technology, applied in battery electrodes, secondary batteries, electrochemical generators, etc., can solve the problems of high preparation cost, prone to agglomeration, expensive raw materials, etc. The effect of interfacial potential energy and high specific capacity

Active Publication Date: 2017-07-07
博尔特新材料(银川)有限公司
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Problems solved by technology

[0005] In the prior art, the research on silicon oxide-based composite materials is mainly obtained by physically mixing and covering silicon oxide, silicon, graphite or organic carbon sources. Since agglomeration and inhomogeneity are prone to occur during the dispersion process, the prepared The particle size distribution of the silica-based composite material is not uniform, which affects the first-time efficiency and cycle stability of the negative active material.
At the same time, commercial silicon and silicon oxide are directly used as raw materials, the raw materials are expensive, and the preparation cost is relatively high.
For example, CN103441250A discloses a lithium-ion secondary battery, a negative electrode material for the secondary battery, and a preparation method. The negative electrode material is a composite particle comprising silicon nanoparticles and conductive metal particles that can be dispersed in silicon oxide. Although the capacity can reach about 600mAh / g, the initial efficiency is less than 70%
CN103022446A discloses a lithium-ion battery silicon oxide / carbon negative electrode material and a preparation method thereof, a three-layer composite material with a core-shell structure, adopting graphite material as the core, porous silicon oxide as the middle layer, and organic pyrolytic carbon as The outermost cladding layer has good cycle performance and specific capacity, and the first Coulombic efficiency can reach 88%. However, the preparation process is complicated, the cost is high, the composite structure is difficult to control, and it is difficult to realize large-scale industrial production.
CN102208634A discloses a porous silicon / carbon composite material and a preparation method thereof, using ethyl orthosilicate, silicon tetrachloride, methyl silicone oil, and sodium silicide as raw materials to prepare porous silica, and then porous silica It is reduced to porous silicon, then coated with an organic carbon source, and then heat-treated in an inert atmosphere to prepare a porous silicon / carbon composite material. The first reversible capacity of the composite material can reach about 1245mAh / g, but the prepared composite material Large silicon particles lead to obvious volume expansion effect of the composite material, rapid capacity cycling decay, and the preparation process of this method is complicated

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  • Lithium ion battery silicon oxide and carbon composite negative pole material and preparation method thereof

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[0032] The preparation method of silicon oxide and carbon composite negative electrode material of lithium ion battery of the present invention comprises the following steps:

[0033] 1. Preparation of nano-silica sol

[0034] Under room temperature (20 ± 5 ℃), according to prior art preparation mass concentration is the alkaline aqueous solution of 5.0~20%, in alkaline aqueous solution, add the nonionic surface active agent that quality is alkaline aqueous solution 1.5~4.0%, control The rotation speed is 150-800r / min, after mechanically stirring the mixed solution for 25-55min, slowly add silicon tetrachloride under stirring, so as not to cause splashing and the mixed solution does not splash on the wall of the vessel where it is located, until the pH of the mixed solution is reached. The value is 6.5-7.5, continue to stir for 40-100 minutes, and then let stand for 2-8 hours to obtain nano-silica sol in a stable state.

[0035] The alkaline aqueous solution solute is more th...

Embodiment 1

[0067] 1. In 500g of sodium hydroxide aqueous solution with a mass concentration of 5.0%, add 7.5g of polyethylene glycol with a mass purity of 99% or more, control the rotation speed at 150r / min, and after mechanical stirring for 25min, slowly add tetrachloride under stirring Silica until the pH of the mixed solution is 6.5, continue to stir and react for 40 minutes, and then stand and age for 2 hours to obtain nano-silica sol in a stable state.

[0068] 2. Weigh the reducing agent zinc powder according to the molar ratio of metal zinc to silicon tetrachloride 0.5:1, mix it with spherical natural graphite powder at a mass ratio of 1:9, and place it in an ultrasonic reactor. Control the reactor at a temperature of 25°C and a speed of 800r / min, power density 0.45w / cm 2 , ultrasonically disperse for 30min at a frequency of 20KHz, disperse the mixed powder in absolute ethanol, configure a solution with a mass concentration of 35%, add nano-silica sol, continue ultrasonically dis...

Embodiment 2

[0076] 1. Add 10 g of fatty alcohol polyoxyethylene ether with a purity of 99% or more to 500 g of an aqueous solution of sodium carbonate with a mass concentration of 8.0%, control the speed at 280 r / min, and react with mechanical stirring for 31 min, then slowly add silicon tetrachloride under stirring to The pH value of the mixed solution was 6.5. After continuing to stir and react for 52 minutes, it was allowed to stand and age for 4 hours to obtain a stable nano-silica sol.

[0077] 2. Weigh the reducing agent zinc powder according to the molar ratio of metal zinc to silicon tetrachloride 0.65:1, mix it with the mesophase carbon microspheres at a mass ratio of 3:17, and place it in an ultrasonic reactor. The temperature of the reactor is controlled at 30°C and the speed is 570r / min, power density 0.42w / cm 2 , ultrasonically disperse for 44min at a frequency of 19KHz, disperse the mixed powder in methanol, configure a solution with a mass concentration of 43%, add nano-si...

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Abstract

The invention discloses a lithium ion battery silicon oxide and carbon composite negative pole material and a preparation method thereof. The technical purposes are improvement of first Coulomb effect, capacity and circulating properties and reduction of cost. According to the lithium ion battery silicon oxide and carbon composite negative pole material, a graphite-based silicon oxide composite material serves as a body, the body is wrapped with a pyrolytic carbon wrapping layer of an organic carbon source, and amorphous carbon in the graphite-based silicon oxide composite material is bonded with a silicon oxide and graphite with a nanoporous structure by means of Van der Waals force. The preparation method includes the steps of nano-silica sol preparation, ultrasonic dispersion, primary sintering, wrapping and secondary sintering. Compared with the prior art, stress generated by size change of the silicon oxide during high lithium intercalation and deintercalation is effectively reduced, and interfacial potential energy between materials is effectively reduced, so that the material has high specific capacity, and is suitable for high-rate charge and discharge, simple in preparation method, easy to control, low in cost and suitable for large-scale industrial production.

Description

technical field [0001] The invention relates to a novel energy material and a preparation method thereof, in particular to a lithium-ion battery composite negative electrode material and a preparation method thereof. Background technique [0002] Lithium-ion batteries commercialized in the prior art mainly use graphite-like carbon materials as negative electrode active materials, but the specific capacity of carbon materials is low, and the theoretical capacity is 372mAh / g. The energy density of the battery system composed of positive electrode materials is generally below 150Wh / Kg; at the same time, the lithium intercalation potential of graphite is close to the lithium deposition potential, and low-temperature charging or high-rate charging and discharging are easy to decompose lithium, causing safety problems. Therefore, the graphite-based anode materials in the prior art have been difficult to meet the requirements for the miniaturization of electronic equipment and the ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M4/36H01M4/583H01M4/48H01M4/62H01M10/0525B82Y30/00
CPCB82Y30/00H01M4/366H01M4/48H01M4/583H01M4/625H01M10/0525Y02E60/10
Inventor 王兴蔚马少宁侯春平侯佼
Owner 博尔特新材料(银川)有限公司
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