Graphite/silicon/graphene composite material and preparation method thereof

A silicon composite material and composite material technology, applied in electrical components, electrochemical generators, battery electrodes, etc., can solve the problems of limited development and practical application, deterioration of cycle performance, etc., to improve the first efficiency and cycle performance, and improve the volume. effect of effect

Active Publication Date: 2017-05-31
SHANDONG YUHUANG NEW ENERGY TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, the volume expansion of more than 300% will cause the deterioration of cycle performance, which severely limits the development and practical application of this material.

Method used

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  • Graphite/silicon/graphene composite material and preparation method thereof
  • Graphite/silicon/graphene composite material and preparation method thereof

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0028] 1) Weigh 100g of NMP solution and put it into a 500ml beaker, add 5g of graphene powder and 2g of polyvinylpyrrolidone into the beaker, put the beaker into an ultrasonic cleaner and vibrate ultrasonically for 20min to obtain a graphene dispersion;

[0029] 2) Weigh 87g of natural graphite, 3g of low-temperature coal tar pitch and 5g of nano-silicon powder into the mixer, set the temperature of the mixer at 70°C, and stir at this temperature for 5 hours to obtain a silicon / graphite composite material;

[0030] 3) Continue to stir the graphene dispersion obtained in step 1) and the graphite / silicon composite material obtained in step 2) in a mixer for 1 hour, and the taken out materials are dried, calcined, pulverized, and classified to obtain graphite / silicon / graphene composites.

Embodiment 2

[0032] 1) Weigh 100g of NMP solution into a 500ml beaker, add 7g of graphene powder and 3g of polyvinylpyrrolidone into the beaker, put the beaker into an ultrasonic cleaner and oscillate ultrasonically for 20min to obtain a graphene dispersion;

[0033] 2) Weigh 85g of graphite, 3g of medium-temperature coal tar pitch and 5g of nano-silicon powder into the mixer, set the temperature of the mixer at 90°C, and stir at this temperature for 5 hours to obtain a silicon / graphite composite material;

[0034] 3) Continue to stir the graphene dispersion obtained in step 1) and the graphite / silicon composite material obtained in step 2) in a mixer for 1 hour, and the taken out materials are dried, calcined, pulverized, and classified to obtain graphite / silicon / graphene composites.

Embodiment 3

[0036] 1) Weigh 100g of NMP solution into a 500ml beaker, add 10g of graphene powder and 4g of polyvinylpyrrolidone into the beaker, put the beaker into an ultrasonic cleaner and oscillate ultrasonically for 20min to obtain a graphene dispersion;

[0037] 2) Weigh 82g of graphite, 3g of medium-temperature coal tar pitch and 5g of nano-silicon powder into the mixer, set the temperature of the mixer at 100°C, and stir at this temperature for 5 hours to obtain a silicon / graphite composite material;

[0038] 3) Continue to stir the graphene dispersion obtained in step 1) and the graphite / silicon composite material obtained in step 2) in a mixer for 1 hour, and the taken out material can be dried, calcined, pulverized, and classified to obtain graphite / silicon composite material. Silicon / graphene composites.

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Abstract

The invention relates to the field of lithium ion battery negative pole materials, and particularly discloses a graphite / silicon / graphene composite material and a preparation method thereof. The invention is characterized in that the graphite / silicon / graphene composite material is in a three-layer sandwich structure which is sequentially composed of graphite, nano silicon and graphene from inside to outside. The three-layer structure is composed of 80-90 wt% of graphite, 1-5 wt% of nano silicon and 5-19 wt% of graphene. The graphite and graphene are compounded with the silicon to prepare the three-layer-sandwich-structure graphite / silicon / graphene composite material. The nano silicon is fixed between the graphite and graphene, and prepared by using the inner graphite as the framework and the outer graphene as the buffer layer. The design of the special structure improves the bulk effect of the silicon material in the charge-discharge process, and enhances the initial efficiency and cycle performance of the material.

Description

[0001] (1) Technical field [0002] The invention relates to the field of negative electrode materials for lithium ion batteries, in particular to a graphite / silicon / graphene composite material and a preparation method thereof. [0003] (2) Background technology [0004] Lithium-ion batteries are mainly composed of positive electrode materials, negative electrode materials, electrolyte, separator and other auxiliary materials. The specific capacity of positive and negative electrode materials directly determines the energy density of the battery. The theoretical specific capacity of graphite as the anode material of lithium-ion batteries is 372mAh / g, and the currently applicable commercial graphite has exceeded 360mAh / g, which is very close to its theoretical value, and there is no obvious room for improvement. To further increase the energy density of batteries, new anode materials must be used. Li can be formed when silicon is alloyed with metallic lithium 22 Si 5 At this ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M4/36H01M4/38H01M4/62H01M10/0525
CPCH01M4/366H01M4/386H01M4/62H01M4/625H01M4/628H01M10/0525Y02E60/10
Inventor 唐其伟赵成龙田海燕于恒杰田崇社张朋
Owner SHANDONG YUHUANG NEW ENERGY TECH
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