Sponge-like silicon graphene and carbon nano-tube composite negative electrode material preparation method

Abstract

The present invention discloses a sponge-like silicon graphene and carbon nano-tube composite negative electrode material preparation method, which comprises, by weight, 50-90% of silicon powder, 2-35% of graphene, and 1-25% of carbon nano-tubes. According to the present invention, the composite material prepared by using the freeze-drying or supercritical drying method retains the original skeleton structure, the carbon nano-tubes are adopted as the skeleton support unit and the graphene is adopted as the frame pore structure surface to co-support the three-dimensional electric conduction network composite structure having innumerable pores, and the silicon powder is adsorbed inside the pores; the composite material has characteristics of high conductivity, high structure elasticity, strong adsorption, effective inhibition of the volume expansion effect of the silicon during the charge and discharge process, and improvement of the cycle stability of the material; and the process is simple and environmental protection, and is suitable for industrial production.

Description

technical field

[0001] The invention relates to a lithium ion battery negative electrode material and a preparation method thereof, in particular to a preparation method of a spongy silicon graphene and carbon nanotube composite negative electrode material. Background technique

[0002] At present, the negative electrodes of commercial lithium-ion batteries mainly use carbonaceous materials such as natural graphite and artificial graphite, but the theoretical capacity of these graphitized carbonaceous materials is only 372mAh / g, and the high-rate charge and discharge performance is poor, especially the volume specific capacity. fairly limited. Therefore, there is very little space for further improving its specific capacity, which is far from meeting the needs of future high-capacity and long-life electronic equipment. In recent years, metals and alloys have been the most researched new high-efficiency lithium storage anode material systems, among which pure metal silicon a...

Examples

Embodiment 1

[0017] 1. Disperse 1g of graphene oxide and 1g of carboxylated single-walled carbon nanotubes in 200g of water, and stir evenly to obtain a dispersion of graphene-single-walled carbon nanotubes; then add 5g of silicon powder to the above-mentioned dispersion, stir, Obtain a dispersion of graphene oxide and carbon nanotubes; stir to obtain a mixed solution;

[0018] 2. Transfer the above mixed solution to a hydrothermal kettle, and conduct a hydrothermal reaction at a temperature of 150°C for 18 hours to obtain a graphene-carbon nanotube composite hydrogel containing silicon powder; then freeze-dry the hydrogel, The spongy graphene-carbon nanotube composite airgel material adsorbing silicon powder is obtained, that is, the spongy silicon graphene and carbon nanotube composite negative electrode material.

Embodiment 2

[0020] 1. Disperse 1g of graphene oxide and 1g of carboxylated multi-walled carbon nanotubes in 200g of water, stir evenly to obtain a dispersion of graphene-single-walled carbon nanotubes; then add 10g of silicon powder into the above-mentioned dispersion, stir, Obtain a dispersion of graphene oxide and carbon nanotubes; stir to obtain a mixed solution;

[0021] 2. Transfer the above mixed solution to a hydrothermal kettle, and conduct a hydrothermal reaction at a temperature of 200°C for 18 hours to obtain a graphene-carbon nanotube composite hydrogel containing silicon powder; then the hydrogel is frozen and critically After drying, the spongy graphene-carbon nanotube composite airgel material adsorbing silicon powder is obtained, that is, the spongy silicon graphene and carbon nanotube composite negative electrode material.

Embodiment 3

[0023] 1. Disperse 1g of graphene oxide and 0.5g of carboxylated single-walled carbon nanotubes in 400g of water, and stir evenly to obtain a dispersion of graphene-single-walled carbon nanotubes; then add 8g of silicon powder to the above-mentioned dispersion, and stir , to obtain a dispersion of graphene oxide and carbon nanotubes; stirring to obtain a mixed solution;

[0024] 2. Transfer the above mixed solution to a hydrothermal kettle, and conduct a hydrothermal reaction at a temperature of 200°C for 20 hours to obtain a graphene-carbon nanotube composite hydrogel containing silicon powder; then freeze-dry the hydrogel, The spongy graphene-carbon nanotube composite airgel material adsorbing silicon powder is obtained, that is, the spongy silicon graphene and carbon nanotube composite negative electrode material.

technical field

[0001] The invention relates to a lithium ion battery negative electrode material and a preparation method thereof, in particular to a preparation method of a spongy silicon graphene and carbon nanotube composite negative electrode material. Background technique

[0002] At present, the negative electrodes of commercial lithium-ion batteries mainly use carbonaceous materials such as natural graphite and artificial graphite, but the theoretical capacity of these graphitized carbonaceous materials is only 372mAh / g, and the high-rate charge and discharge performance is poor, especially the volume specific capacity. fairly limited. Therefore, there is very little space for further improving its specific capacity, which is far from meeting the needs of future high-capacity and long-life electronic equipment. In recent years, metals and alloys have been the most researched new high-efficiency lithium storage anode material systems, among which pure metal silicon a...

Examples

Embodiment 1

[0017] 1. Disperse 1g of graphene oxide and 1g of carboxylated single-walled carbon nanotubes in 200g of water, and stir evenly to obtain a dispersion of graphene-single-walled carbon nanotubes; then add 5g of silicon powder to the above-mentioned dispersion, stir, Obtain a dispersion of graphene oxide and carbon nanotubes; stir to obtain a mixed solution;

[0018] 2. Transfer the above mixed solution to a hydrothermal kettle, and conduct a hydrothermal reaction at a temperature of 150°C for 18 hours to obtain a graphene-carbon nanotube composite hydrogel containing silicon powder; then freeze-dry the hydrogel, The spongy graphene-carbon nanotube composite airgel material adsorbing silicon powder is obtained, that is, the spongy silicon graphene and carbon nanotube composite negative electrode material.

Embodiment 2

[0020] 1. Disperse 1g of graphene oxide and 1g of carboxylated multi-walled carbon nanotubes in 200g of water, stir evenly to obtain a dispersion of graphene-single-walled carbon nanotubes; then add 10g of silicon powder into the above-mentioned dispersion, stir, Obtain a dispersion of graphene oxide and carbon nanotubes; stir to obtain a mixed solution;

[0021] 2. Transfer the above mixed solution to a hydrothermal kettle, and conduct a hydrothermal reaction at a temperature of 200°C for 18 hours to obtain a graphene-carbon nanotube composite hydrogel containing silicon powder; then the hydrogel is frozen and critically After drying, the spongy graphene-carbon nanotube composite airgel material adsorbing silicon powder is obtained, that is, the spongy silicon graphene and carbon nanotube composite negative electrode material.

Embodiment 3

[0023] 1. Disperse 1g of graphene oxide and 0.5g of carboxylated single-walled carbon nanotubes in 400g of water, and stir evenly to obtain a dispersion of graphene-single-walled carbon nanotubes; then add 8g of silicon powder to the above-mentioned dispersion, and stir , to obtain a dispersion of graphene oxide and carbon nanotubes; stirring to obtain a mixed solution;

[0024] 2. Transfer the above mixed solution to a hydrothermal kettle, and conduct a hydrothermal reaction at a temperature of 200°C for 20 hours to obtain a graphene-carbon nanotube composite hydrogel containing silicon powder; then freeze-dry the hydrogel, The spongy graphene-carbon nanotube composite airgel material adsorbing silicon powder is obtained, that is, the spongy silicon graphene and carbon nanotube composite negative electrode material.