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Preparation method of high-performance silicon carbon-graphite composite negative electrode material for lithium ion batteries

A technology of silicon-carbon composite materials and lithium-ion batteries, applied in the preparation/purification of carbon, nanotechnology for materials and surface science, battery electrodes, etc., can solve the problems of silicon-carbon negative electrode cycle performance failure, nano-silicon easy to fall off, Weak adhesion and other problems, to achieve the effect of easy industrial production, low cost and long cycle life

Active Publication Date: 2020-02-28
HUNAN SHINZOOM TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

In this method, nano-silicon is only attached to the surface of graphite particles, the adhesion is weak, and nano-silicon is easy to fall off during the spheroidization process, and there is no space to provide expansion buffer for silicon, and nano-silicon is easy to pulverize, resulting in failure of silicon-carbon negative electrode cycle performance.

Method used

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  • Preparation method of high-performance silicon carbon-graphite composite negative electrode material for lithium ion batteries
  • Preparation method of high-performance silicon carbon-graphite composite negative electrode material for lithium ion batteries

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0028] ① Dissolve 100g pitch in 1000g diesel solution to make a solution, then add 100g 100nm nano silicon powder (purity 99.9%) and mix uniformly to make a dispersion; ②Put the dispersion into a vacuum-high pressure impregnation reactor and add 1800g 15μm flake graphite (Carbon content>99.0%), first immerse in a vacuum state for 0.5h (vacuum degree is -80kPa), then pressurize to 4.0MPa (pressurized gas is nitrogen), immerse for 4h, and vacuum dry at 120℃ to obtain silicon-carbon composite material Silicon-carbon composite material precursor; ③Transfer the silicon-carbon composite material precursor to the spheroidization equipment to obtain the spheroidized composite material precursor; ④The spheroidized composite material precursor is solid-coated with 5% pitch to obtain a coating Spheroidizing precursor 3; ⑤ Place the precursor 3 in a high-purity nitrogen atmosphere furnace for carbonization (flow 2000L / h), the heating rate of the carbonization furnace is 3°C / min, the tempera...

Embodiment 2

[0030] ① Dissolve 100g of chitosan in 1000g of anhydrous ethanol solution to prepare a solution, then add 100g of 30nm nano silicon powder (purity 99.9%) and mix uniformly to prepare a dispersion; ②Put the dispersion into a vacuum-high pressure impregnation reactor and add 1800g 15μm flake graphite (carbon content>99.0%), first immerse in a vacuum state for 0.3h (vacuum degree is -80kPa), then pressurize to 5.0MPa (pressurized gas is helium), immerse for 3h, and vacuum dry at 130°C Obtain the silicon-carbon composite material precursor; ③The silicon-carbon composite material precursor is transferred to the spheroidization equipment to obtain the spheroidized composite material precursor; ④The spheroidized composite material precursor is solid-coated with 6% phenolic resin , The coated spheroidizing precursor 3 was prepared; ⑤The coated spheroidizing precursor was carbonized in a high-purity nitrogen atmosphere furnace (flow rate 2000L / h), the heating rate of the carbonization fu...

Embodiment 3

[0032] ① Dissolve 100g phenolic resin in 1000g acetone solution to prepare a solution, then add 100g 30nm nano silicon powder (purity 99.9%) and mix uniformly to make a dispersion; ②Put the dispersion into a vacuum-high pressure impregnation reactor and add 1800g 15μm flakes Graphite (carbon content>99.0%), first immerse and react under vacuum for 0.5h (vacuum degree is -80kPa), then pressurize to 2.0MPa (pressurized gas is argon), immerse and react for 5h, vacuum dry at 150℃ to obtain silicon carbon Composite material silicon-carbon composite material precursor; ③Transfer the silicon-carbon composite material precursor to the spheroidization equipment to obtain the spheroidized composite material precursor; ④The spheroidized composite material precursor is solid-coated with 5% pitch to prepare Coating the spheroidizing precursor 3; ⑤ Place the precursor 3 in a high-purity nitrogen atmosphere furnace for carbonization (flow rate 2000L / h), the heating rate of the carbonization fu...

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Abstract

The invention discloses a preparation method of a high-performance silicon carbon-graphite composite negative electrode material for lithium ion batteries. The preparation method comprises the following steps: dissolving an organic carbon source in a solvent, adding nano silicon particles, uniformly mixing, adding crystalline flake graphite into an obtained mixture, carrying out continuous vacuum-high pressure impregnation reaction, and carrying out vacuum drying to obtain a silicon carbon composite material precursor; and spheroidizing the silicon carbon composite material precursor, carryingout surface solid-phase coating, and finally, carrying out sintering and screening to obtain the target product. According to the invention, the contact between nano silicon and electrolyte is greatly reduced to form a stable solid electrolyte membrane, and the target product has the characteristics of high first effect, long cycle and the like, and the application prospect is promising.

Description

Technical field [0001] The invention relates to the field of lithium ion battery negative electrode materials, in particular to a method for preparing a high-performance silicon carbon-graphite composite negative electrode material. Background technique [0002] Lithium-ion batteries are popular for their excellent performance such as high capacity, high voltage, high cycle stability, high energy density and no pollution to the environment. As a negative electrode material, silicon has the advantage of high specific capacity (4200mAh / g), but its significant disadvantage is the large volume expansion (up to 300%) after lithium ion intercalation. Repeated deintercalation of lithium ion will gradually pulverize the material and cause the structure to collapse. Finally, the cycle performance of the battery is greatly reduced. [0003] Natural graphite has the characteristics of high first effect, good electrolyte compatibility, and good cycle performance. Through the combination of na...

Claims

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Application Information

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IPC IPC(8): C01B33/02C01B32/05C01B32/20H01M4/38H01M4/587H01M4/62H01M10/0525B82Y30/00
CPCB82Y30/00C01B33/02C01B32/05C01B32/20H01M4/386H01M4/587H01M4/625H01M10/0525Y02E60/10
Inventor 黎建锋皮涛王志勇肖志平邵浩明曾仔明唐唯
Owner HUNAN SHINZOOM TECH
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