Method for preparation of graphene/nano-silicon lithium ion battery cathode material by liquid phase physical technique

A technology for lithium ion batteries and negative electrode materials, applied in battery electrodes, secondary batteries, circuits, etc., can solve problems such as hindering performance, easy stacking and re-agglomeration, application field limitations, etc., to overcome poor conductivity, simple process, overcome silicon The effect of large volume changes

Active Publication Date: 2015-10-21
BEIHANG UNIV
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

However, the preparation of graphene by liquid-phase physical method also has shortcomings, such as the defect that it is easy to stack and reunite, which will hinder its performance and limit its application field.

Method used

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  • Method for preparation of graphene/nano-silicon lithium ion battery cathode material by liquid phase physical technique
  • Method for preparation of graphene/nano-silicon lithium ion battery cathode material by liquid phase physical technique
  • Method for preparation of graphene/nano-silicon lithium ion battery cathode material by liquid phase physical technique

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Experimental program
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Effect test

Embodiment 1

[0034] Embodiment 1 Graphene and nano-silicon composite material preparation and electrochemical performance test

[0035] Preparation of graphene and nano-silicon composites

[0036] Step 1: take by weighing 40mg surface modifier CTAB, add 40mL deionized water, vigorously stir 12h, make surface modifier fully dissolve in water, obtain the solution (CTAB mass ratio for preparing graphene and nano-silicon composite material is 0.1%);

[0037] Step 2: Weigh 200mg of graphite powder (particle size less than 325 mesh) and 15mg of nano-silicon powder and add it to the prepared solution, stir until it is uniformly dispersed, and obtain a mixed dispersion of graphite powder and nano-silicon powder (the mass ratio of graphite powder is 0.5%, Nano silicon powder mass ratio 0.0375%), and it is packed in the screw-top glass bottle with lid;

[0038] Step 3: soak the screw-top glass bottle containing the graphite dispersion in the container of the ultrasonic cavitation generator (pre-fi...

Embodiment 2

[0049] Embodiment 2 Graphene and nano-silicon composite material preparation and electrochemical performance test

[0050] Preparation of graphene and nano-silicon composites

[0051] Step 1: Weigh 40 mg of surface modifier CTAB, add 40 mL of deionized water, and stir vigorously for 12 hours to fully dissolve the surface modifier in water to obtain a solution for preparing graphene and silicon composites (CTAB mass ratio is 0.1 %);

[0052] Step 2: Add 15 mg of nano-silica powder to the prepared solution, stir and ultrasonically disperse for 4 hours until it is uniformly dispersed, put it into a centrifuge for centrifugal separation, take the upper liquid to obtain a dispersion of nano-silica powder; the centrifugal speed is 2000rpm, and the centrifugal The time is 0.5h; then 200mg of graphite powder (particle size less than 325 mesh) is added to the nano-silicon powder dispersion (graphite powder mass ratio 0.5%), stirred until it is uniformly dispersed to obtain a mixed dis...

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Abstract

The invention relates to a method for preparation of a graphene/nano-silicon lithium ion battery cathode material by liquid phase physical technique. The preparation steps include: 1. dissolving a surfactant in deionized water in proportion to obtain a solution; 2. dispersing graphite powder and nano-silicon powder uniformly in the solution; 3. conducting ultrasonic cavitation treatment on the graphite powder and nano-silicon powder mixed dispersion solution; 4. carrying out centrifugal separation treatment on the solution; 5. standing the solution for certain time and taking the upper solution; 6. subjecting the supernatant to vacuum pumping filtration and drying to obtain grey powder; and 7. calcining the grey powder to obtain the graphene/nano-silicon composite material. The preparation process involved in the invention is simple and practicable, graphene and nano-silicon particles have good dispersibility, thus avoiding agglomeration of liquid phase method prepared graphene, and omitting secondary dispersion of liquid phase physical method prepared grapheme. Constant current charging-discharging result shows that the grapheme/silicon composite material overcomes the disadvantages of large volume change and poor electrical conductivity of silicon, and improves the performance of lithium ion battery cathode materials.

Description

Technical field: [0001] The invention relates to a method for preparing graphene / nano-silicon lithium-ion battery negative electrode material by a liquid-phase physical method, in particular to a method for directly preparing graphene and nano-silicon composite materials in an aqueous surface modifier solution and using it as a lithium-ion battery negative electrode material technology. It belongs to the new application field of graphene prepared by liquid phase physical method and used as lithium ion battery material. Background technique: [0002] Lithium-ion batteries dominate portable power supplies due to their advantages of high open circuit voltage, long cycle life, high energy density, low self-discharge, and no memory effect. In order to meet the requirements of miniaturization of electronic equipment and high power of large equipment, improving energy density and rate performance has become an important development direction of lithium-ion batteries. [0003] As ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M4/36H01M4/38H01M4/587H01M10/0525
CPCH01M4/364H01M4/386H01M4/587H01M10/0525Y02E60/10
Inventor 沈志刚刘虹张晓静麻树林
Owner BEIHANG UNIV
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