Modified graphite and its preparing method

Abstract

Modified graphite includes granules of graphite core material and amorphous carbon membrane layer. Distance of between micro crystal layers d002 as 0.335-0.340 nm. Specific surface area of modified graphite is 1.3-4.2m2 / g and average particle diameter is 8-35 micro. The preparing method includes following steps: dipping granules of graphite core material in solution of polymer coating materials; then through mixing, separating, sieving, solidifying and carbonizing steps. Advantages are: large current, higher reversible specific capacity, longer cycle life. Features are simple, low cost and easy for industrialization production.

Description

Technical field

[0001] The invention relates to a modified graphite and a preparation method thereof, more specifically to a modified graphite with excellent high-current performance and a preparation method thereof.

Background technique

[0002] With the rapid development of the electronics industry and the information industry, people have higher and higher requirements for the power supply of various electrical products. Lithium-ion secondary batteries have developed rapidly and are widely used in the past ten years due to their superior comprehensive performance.

[0003] As the functions of electrical products, especially portable electrical products, are becoming more and more complex, and the volume is becoming smaller and smaller, the requirements for the power supply are also increasing, which is reflected in: sufficiently high volumetric energy density, superior high-current performance, suitable cycle life and reliability. The safety performance, especially th...

Examples

preparation example Construction

[0047]In the present invention, the modified graphite is mainly obtained by surface modification treatment of natural graphite or artificial graphite with a relatively high degree of graphitization. The preparation method includes the following steps: pre-preparing an organic solution of a polymer surface modifier with a certain concentration (generally saturated or close to saturation); immersing the graphite core material in it and stirring it, the stirring speed is 100-2000rpm, and the stirring time 0.5~10h; then separate (filter or centrifuge) the graphite in it, dry the solvent involved in it, and sieve; finally, the dry graphite obtained is solidified and carbonized under a protective atmosphere without crushing process The modified graphite of the present invention can be obtained.

[0048] In the preparation method of modified graphite of the present invention, described surface modifier is a kind of very high organic matter of carbon content, can be coal pitch, coal t...

Embodiment 1

[0055] Weigh 8 g of petroleum tar, dissolve it in carbon tetrachloride, and prepare 200 ml of a 4% surface modifier solution for later use. Weigh 100g of dry natural graphite, dip it in the organic solution of the surface modifier, and stir it at a speed of 300rpm for 1 hour, so that a thin layer of surface modification film is formed on the surface of the graphite particles. Then filter to obtain graphite, dry, and pass through a 300-mesh sieve. Put the sieved graphite into a closed tubular high-temperature furnace, and pass high-purity N at a flow rate of 10 liters / min. 2 , the heating rate was raised to 400°C at a rate of 15°C / min, kept for 1 hour, and then raised to 1000°C at a rate of 10°C / min, kept at a temperature of 3 hours, and naturally cooled to room temperature to obtain surface-modified graphite. The graphite is D 50 The average particle size of the characterization is 13.8μm, and the distance between the crystallite layers is d 002 is 0.3365, and the specific ...

Embodiment 2

[0058] In this example, the surface modification agent is 5% coal tar pitch in tetrahydrofuran solution, except that, other processes are consistent with Example 1. The average particle diameter D of the modified graphite that present embodiment obtains 50 and crystallite interlayer spacing d 002 Basically consistent with Example 1.

Technical field

[0001] The invention relates to a modified graphite and a preparation method thereof, more specifically to a modified graphite with excellent high-current performance and a preparation method thereof.

Background technique

[0002] With the rapid development of the electronics industry and the information industry, people have higher and higher requirements for the power supply of various electrical products. Lithium-ion secondary batteries have developed rapidly and are widely used in the past ten years due to their superior comprehensive performance.

[0003] As the functions of electrical products, especially portable electrical products, are becoming more and more complex, and the volume is becoming smaller and smaller, the requirements for the power supply are also increasing, which is reflected in: sufficiently high volumetric energy density, superior high-current performance, suitable cycle life and reliability. The safety performance, especially th...

Examples

preparation example Construction

[0047]In the present invention, the modified graphite is mainly obtained by surface modification treatment of natural graphite or artificial graphite with a relatively high degree of graphitization. The preparation method includes the following steps: pre-preparing an organic solution of a polymer surface modifier with a certain concentration (generally saturated or close to saturation); immersing the graphite core material in it and stirring it, the stirring speed is 100-2000rpm, and the stirring time 0.5~10h; then separate (filter or centrifuge) the graphite in it, dry the solvent involved in it, and sieve; finally, the dry graphite obtained is solidified and carbonized under a protective atmosphere without crushing process The modified graphite of the present invention can be obtained.

[0048] In the preparation method of modified graphite of the present invention, described surface modifier is a kind of very high organic matter of carbon content, can be coal pitch, coal t...

Embodiment 1

[0055] Weigh 8 g of petroleum tar, dissolve it in carbon tetrachloride, and prepare 200 ml of a 4% surface modifier solution for later use. Weigh 100g of dry natural graphite, dip it in the organic solution of the surface modifier, and stir it at a speed of 300rpm for 1 hour, so that a thin layer of surface modification film is formed on the surface of the graphite particles. Then filter to obtain graphite, dry, and pass through a 300-mesh sieve. Put the sieved graphite into a closed tubular high-temperature furnace, and pass high-purity N at a flow rate of 10 liters / min. 2 , the heating rate was raised to 400°C at a rate of 15°C / min, kept for 1 hour, and then raised to 1000°C at a rate of 10°C / min, kept at a temperature of 3 hours, and naturally cooled to room temperature to obtain surface-modified graphite. The graphite is D 50 The average particle size of the characterization is 13.8μm, and the distance between the crystallite layers is d 002 is 0.3365, and the specific ...

Embodiment 2

[0058] In this example, the surface modification agent is 5% coal tar pitch in tetrahydrofuran solution, except that, other processes are consistent with Example 1. The average particle diameter D of the modified graphite that present embodiment obtains 50 and crystallite interlayer spacing d 002 Basically consistent with Example 1.

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