Three-dimensional spherical silicon-carbon composite negative electrode material and preparation method therefor

A silicon-carbon composite and anode material technology, applied in battery electrodes, electrical components, electrochemical generators, etc., can solve the problems of insufficient initial efficiency and cycle life, and achieve excellent cycle and rate performance, high specific capacity, and reduced ratio The effect of surface area

Inactive Publication Date: 2017-10-03
CHENGDU GUIBAO SCI & TECH +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0004] The present invention overcomes the deficiencies of the prior art, and provides a three-dimensional spherical silicon-carbon composite negative electrode material and its

Method used

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  • Three-dimensional spherical silicon-carbon composite negative electrode material and preparation method therefor
  • Three-dimensional spherical silicon-carbon composite negative electrode material and preparation method therefor

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0028] At room temperature, disperse 1g of nano-silicon with a particle size of 50-100nm in a mixture of 50mL of ethanol and water, the volume ratio of ethanol to water is 5:1, and then add 1g of phenolic resin and 0.5g of ten Hexaalkyltrimethylammonium bromide, and then electromagnetically stir the mixed solution at a speed of 200rpm for 60min; the resulting solution is spray-dried, the spray drying inlet air temperature is 170°C, the outlet air temperature is 100°C, and the feed rate is 5mL / min, the Si@C precursor is obtained; in an argon atmosphere, the Si@C precursor is heated to 700°C at a heating rate of 10°C / min, and sintered at 700°C for 3h, and the Si @C material; disperse 0.2g of Si@C material and 1g of graphite in a mixture of 60mL of ethanol and water, the volume ratio of ethanol to water is 5:1, and then add 0.06g of sodium lauryl sulfate to the mixture and 0.12g of phenolic resin, and the mixed solution was electromagnetically stirred at 120rpm for 60min; the res...

Embodiment 2

[0030] At room temperature, disperse 1g of nano-silicon with a particle size of 30-50nm in a mixture of 150mL of ethanol and water, the volume ratio of ethanol to water is 5:1, and then add 2g of phenolic resin and 1g of dodecane to the mixture. Sodium alkylbenzene sulfonate, then electromagnetically stir the mixed solution at a speed of 180rpm for 120min; the resulting solution is spray-dried, the spray-drying inlet air temperature is 250°C, the outlet air temperature is 120°C, and the feed rate is 8mL / min. The Si@C precursor was obtained; under a nitrogen atmosphere, the Si@C precursor was heated to 900°C at a heating rate of 2°C / min, and sintered at 900°C for 5 hours to obtain a Si@C material; 0.5g of Si@C material and 0.5g of graphite were dispersed in a mixture of 150mL of ethanol and water, the volume ratio of ethanol to water was 4:1, and then 1g of polyvinylpyrrolidone and 1g of phenolic resin were added to the mixture, and the speed was 200rpm Electromagnetically stir...

Embodiment 3

[0032]At room temperature, disperse 1g of nano-silicon with a particle size of 150-200nm in a mixture of 200mL of ethanol and water, the volume ratio of ethanol to water is 1:2, and then add 5g of glucose and 2g of carboxymethyl to the mixture Sodium cellulose, and then electromagnetically stirred the mixed solution at a speed of 120rpm for 80min; spray-dried the obtained solution, the spray-drying inlet air temperature was 220°C, the outlet air temperature was 110°C, and the feed rate was 15mL / min to obtain Si @C precursor; in an argon atmosphere, the Si@C precursor was heated to 800 °C at a heating rate of 5 °C / min, and sintered at 800 °C for 3 hours to obtain a Si@C material; 0.25 g The Si@C material and 0.75g graphite were dispersed in a mixture of 100mL ethanol and water, the volume ratio of ethanol and water was 1:2, and then 0.4g sodium alginate and 0.5g polyvinyl alcohol were added to the mixture, at 180rpm The rotating speed electromagnetically stirred the mixed solut...

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Abstract

The invention discloses a three-dimensional spherical silicon-carbon composite negative electrode material and a preparation method therefor, and belongs to the field of the lithium ion battery negative electrode material. The composite negative electrode material consists of graphite, silicon and amorphous state carbon, wherein graphite and silicon are coated in the amorphous state carbon. The preparation method comprises the steps of dispersing nanometer silicon and a carbon source into an organic solvent, performing spray drying to obtain a Si@C precursor, and performing carbonization to obtain a Si@C material, wherein the volume expansion effect of silicon can be effectively relieved by the surface carbon layer; and next, dispersing the Si@C material, graphite and the carbon source into the organic solvent, performing spray drying to obtain a silicon-carbon composite negative electrode material precursor, and performing carbonization to obtain the three-dimensional spherical silicon-carbon composite negative electrode material. By virtue of the dual-layer amorphous state carbon layers, the volume expansion effect of silicon in the charge-discharge process can be effectively relieved; the amorphous state carbon layer on the outer layer has small specific surface area, so that high irreversible capacity loss is avoided; and therefore, the obtained material has relatively high specific capacity and initial efficiency and excellent cycling stability.

Description

technical field [0001] The invention relates to the field of negative electrode materials for lithium ion batteries, and more specifically, the invention relates to a three-dimensional spherical silicon-carbon composite negative electrode material and a preparation method thereof. Background technique [0002] At present, the anode materials of commercial lithium-ion batteries use graphite-like carbon materials, which have the advantages of low lithium extraction potential, suitable reversible capacity, high initial efficiency and cycle stability, abundant resources, and low price. An ideal lithium-ion battery anode material. However, its theoretical specific capacity is only 372mAh / g, which is difficult to meet the growing demands of high specific energy 3C products and electric vehicles. Because of its high theoretical specific capacity (4200mAh / g), abundant reserves and low price, silicon can become one of the substitute materials for graphite anode materials. However, ...

Claims

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Application Information

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IPC IPC(8): H01M4/36H01M4/583H01M4/62H01M10/0525C01B32/20
CPCH01M4/366H01M4/583H01M4/625H01M10/0525Y02E60/10
Inventor 刘方明彭工厂刘圣洁万琦黄强刘文静王有治瞿美臻
Owner CHENGDU GUIBAO SCI & TECH
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