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A kind of silicon/graphite/lithium titanate composite negative electrode material and preparation method thereof

A negative electrode material, lithium titanate technology, applied in battery electrodes, electrical components, circuits, etc., can solve the problems of unstable SEI film and low coulombic efficiency of negative electrode materials, so as to avoid thickening, improve coulombic efficiency and cycle stability Effect

Active Publication Date: 2017-01-11
CHERY AUTOMOBILE CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0006] In the cycle process, the anode materials provided by the prior art tend to form an unstable and gradually thickened SEI film, resulting in low Coulombic efficiency of the anode materials

Method used

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  • A kind of silicon/graphite/lithium titanate composite negative electrode material and preparation method thereof
  • A kind of silicon/graphite/lithium titanate composite negative electrode material and preparation method thereof
  • A kind of silicon/graphite/lithium titanate composite negative electrode material and preparation method thereof

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preparation example Construction

[0038] On the one hand, an embodiment of the present invention provides a method for preparing a silicon / graphite / lithium titanate composite negative electrode material. The method includes the following steps:

[0039] Step 101: Perform surface hydroxylation treatment on the elemental silicon particles to obtain hydroxylated elemental silicon particles. That is, the surface of the elemental silicon particles is bonded with hydroxyl groups.

[0040] In order to effectively bind hydroxyl groups on the surface of silicon particles, preferably, the above-mentioned surface hydroxylation treatment of elemental silicon particles specifically includes: adding elemental silicon particles to a mixed solution composed of ammonia, hydrogen peroxide and water, heating to boiling, and stirring 10 -60 min, the surface of the elemental silicon particles is combined with hydroxyl groups, and then washed with water, filtered and vacuum dried at 80-120° C. for 2-12 hours to obtain hydroxylated eleme...

Embodiment 1

[0067] This embodiment provides a silicon / graphite / lithium titanate composite anode material, and the preparation steps are as follows:

[0068] Put 2.0g of silicon powder (with a particle size of 100nm) into a mixed solution consisting of 4ml of ammonia (25% mass fraction), 4ml of hydrogen peroxide (30% mass fraction) and 20ml of water, heat it to boiling, and then boil Stir for 30min under the state. Then the solid product was taken out, washed with water, filtered, and vacuum dried at 100° C. for 8 hours to obtain hydroxylated elemental silicon particles.

[0069] Add 1.0g of the hydroxylated elemental silicon particles to the absolute ethanol solution containing tetrabutyl titanate (the volume of the absolute ethanol is 10ml), stir for 6h, and then add 0.2ml to the absolute ethanol solution After stirring for 60 minutes, add 3.5g graphite (artificial graphite with a particle diameter of 5 microns) to the absolute ethanol solution. After stirring, add 0.287g lithium acetate to ...

Embodiment 2

[0076] This embodiment provides a silicon / graphite / lithium titanate composite anode material, and the preparation steps are as follows:

[0077] Put 2.0g of silicon powder (with a particle size of 50nm) into a mixed solution consisting of 4ml of ammonia (25% mass fraction), 4ml of hydrogen peroxide (30% mass fraction) and 20ml of water, heat it to boiling, and Stir for 10min under the state. Then the solid product was taken out, washed with water, filtered, and vacuum dried at 80° C. for 12 hours to obtain hydroxylated elemental silicon particles.

[0078] Add 1.0g of the hydroxylated elemental silicon particles to the absolute ethanol solution containing tetraisopropyl titanate (the volume of the absolute ethanol is 10ml), stir for 2h, and then add 0.2 to the absolute ethanol solution ml of water, continue to stir for 10 minutes, then add 5.65g graphite (natural graphite with a particle size of 1 micron) to the absolute ethanol solution, and after stirring, add 0.51g lithium nitr...

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Abstract

The invention discloses a silicon / graphite / lithium titanate composite negative electrode material and a preparation method thereof, belonging to the field of lithium ion battery negative electrode materials. The method comprises: after carrying out surface hydroxylation treatment on the elemental silicon particles, adding it into an anhydrous ethanol solution containing a titanium source, stirring for 2-10 hours, then adding water, continuing to stir for 15-75 minutes, and then adding graphite, After stirring evenly, then add the dehydrated ethanol solution containing lithium source, after stirring evenly, add glacial acetic acid, and stir until the reaction system changes from a sol system to a gel system; the gel system is aged for 8-14h, and the Dry it at 70-90°C for 8-16h; in an inert atmosphere, calcinate the dried gel system and cool it to room temperature naturally to obtain silicon / graphite / titanium with excellent coulombic efficiency and cycle stability Lithium Oxide Composite Anode Material.

Description

Technical field [0001] The invention relates to the field of negative electrode materials for lithium ion batteries, in particular to a silicon / graphite / lithium titanate composite negative electrode material and a preparation method thereof. Background technique [0002] Lithium battery (ie lithium ion battery) is a rechargeable battery that uses carbon active material as the negative electrode and lithium-containing compound as the positive electrode. The charging and discharging process is the intercalation and deintercalation process of lithium ions: during charging, lithium ions are deintercalated from the positive electrode, and inserted into the negative electrode through the electrolyte and separator. The more lithium ions are embedded in the negative electrode, the higher the charge capacity of the battery will be. ; On the contrary, when discharging, lithium ions are extracted from the negative electrode and inserted into the positive electrode through the electrolyte an...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H01M4/133H01M4/134H01M4/136H01M4/583H01M4/1393H01M4/1395H01M4/1397
CPCH01M4/133H01M4/134H01M4/136H01M4/1393H01M4/1395H01M4/1397H01M4/583Y02E60/10
Inventor 赵志刚朱广燕梅周盛
Owner CHERY AUTOMOBILE CO LTD