Preparation method of flexible self-supporting silicon/graphene cathode material of lithium ion battery

A lithium-ion battery, graphene negative electrode technology, applied in battery electrodes, nanotechnology for materials and surface science, secondary batteries, etc., can solve the problem of limiting the commercial application of silicon-based negative electrodes, reducing electrochemical performance, and hindering ion transport and other issues to achieve the effect of avoiding rapid decline, avoiding capacity, and ensuring high capacity

Inactive Publication Date: 2019-03-26
XIAN UNIV OF SCI & TECH
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  • Abstract
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  • Claims
  • Application Information

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Problems solved by technology

Due to the huge volume expansion (>300%) of silicon in the charging and discharging process of lithium-ion batteries, the pulverization and fragmentation of silicon itself occurs, and the continuous formation of SEI film on the surface of silicon is exposed to the electrolyte, resulting in rapid decline in capacity an...

Method used

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  • Preparation method of flexible self-supporting silicon/graphene cathode material of lithium ion battery
  • Preparation method of flexible self-supporting silicon/graphene cathode material of lithium ion battery
  • Preparation method of flexible self-supporting silicon/graphene cathode material of lithium ion battery

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Embodiment 1

[0032] The preparation method of the present embodiment comprises the following steps:

[0033]Step 1. Disperse 200 mg of nano-silicon particles in 250 mL of boiling mixed solution and heat for 40 minutes, then wash with deionized water for 3 times and then centrifuge; the size of the nano-silicon particles is 50 nm to 100 nm; Aqueous ammonia with a concentration of 25%, hydrogen peroxide and water with a mass concentration of 20% are prepared according to a volume ratio of 1:1:5;

[0034] Step 2. Disperse the precipitate obtained by centrifugation in step 1 in a polydiene dimethyl ammonium chloride solution at room temperature for ultrasonic treatment for 1 hour, and then wash it with deionized water for 5 times. Vacuum drying to obtain positively charged nano-silicon particles;

[0035] Step 3, the positively charged nano-silicon particles obtained in step 2 are formulated into 20 mL of nano-silicon solution with a concentration of 1 mg / mL and ultrasonically treated, and th...

Embodiment 2

[0043] The preparation method of the present embodiment comprises the following steps:

[0044] Step 1. Disperse 200 mg of nano-silicon particles in 250 mL of boiling mixed solution and heat for 40 min, then wash with deionized water for 3 times and then centrifuge; the mixed solution is composed of 25% ammonia water and 20% Hydrogen peroxide and water are prepared according to the volume ratio of 1:1:4;

[0045] Step 2. Disperse the precipitate obtained by centrifugation in step 1 in a polydiene dimethyl ammonium chloride solution at room temperature for ultrasonic treatment for 1 hour, and then wash it with deionized water for 5 times. Vacuum drying to obtain positively charged nano-silicon particles;

[0046] Step 3, the positively charged nano-silicon particles obtained in step 2 are formulated into 20 mL of nano-silicon solution with a concentration of 1 mg / mL and ultrasonically treated, and then added dropwise to 10 mL of a graphene oxide solution with a concentration o...

Embodiment 3

[0050] The preparation method of the present embodiment comprises the following steps:

[0051] Step 1. Disperse 200 mg of nano-silicon particles in 250 mL of boiling mixed solution and heat for 40 min, then wash with deionized water for 3 times and then centrifuge; the mixed solution is composed of 25% ammonia water and 20% Hydrogen peroxide and water are prepared according to the volume ratio of 1:1:5;

[0052] Step 2. Disperse the precipitate obtained by centrifugation in step 1 in a polydiene dimethyl ammonium chloride solution at room temperature for ultrasonic treatment for 1 hour, and then wash it with deionized water for 5 times. Vacuum drying to obtain positively charged nano-silicon particles;

[0053] Step 3, the positively charged nano-silicon particles obtained in step 2 are formulated into 20 mL of nano-silicon solution with a concentration of 1 mg / mL and ultrasonically treated, and then added dropwise to 10 mL of a graphene oxide solution with a concentration o...

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Abstract

The invention discloses a preparation method of a flexible self-supporting silicon/graphene cathode material of a lithium ion battery. The method comprises the following steps: I, dispersing nano silicon particles in a mixed solution to be heated and cleaned and centrifugalized; II, dispersing the centrifugalized precipitate in a polydiene dimethyl ammonium chloride solution to obtain the nano silicon particles with positive charges; III, dropwise adding the nano silicon particles into a graphene oxide solution and carrying out suction filtration to obtain a silicon/graphene oxide composite film; and IV, thermally treating the silicon/graphene oxide composite film at a high temperature to obtain the flexible self-supporting silicon/graphene cathode material. The nano silicon particles withpositive charges and the graphene oxide with negative charges are self-assembled statically to botain the flexible self-supporting silicon/graphene cathode material which is excellent in mechanical flexibility. An electrode of the lithium ion battery can be directly prepared without adding a binder and conducting carbon black, so that the problem that the electrochemical property is reduced by adding the binder is solved, and the service life of the lithium ion battery is prolonged while the high capacity of the lithium ion battery is ensured.

Description

technical field [0001] The invention belongs to the technical field of preparation of negative electrode materials of lithium ion batteries, and in particular relates to a preparation method of flexible self-supporting silicon / graphene negative electrode materials of lithium ion batteries. Background technique [0002] With the earth's energy crisis and the deteriorating environment, research on efficient, clean, and sustainable energy development has become the focus of energy development, and the development of flexible lithium-ion batteries has attracted great attention. However, the theoretical capacity (372mAh / g) of graphite anodes in commercial lithium-ion batteries is greatly limited and cannot meet the needs of applications in high-power devices. [0003] Silicon (Si) is considered as a promising anode material for lithium-ion batteries due to its highest theoretical capacity (4200mAh / g). Due to the huge volume expansion (>300%) of silicon in the charging and dis...

Claims

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Application Information

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IPC IPC(8): H01M4/36H01M4/38H01M4/62H01M10/0525B82Y30/00
CPCB82Y30/00H01M4/366H01M4/386H01M4/628H01M10/0525Y02E60/10
Inventor 张亚婷张凯博贾凯丽刘国阳李可可邱介山
Owner XIAN UNIV OF SCI & TECH
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