Negative electrode material, preparation method thereof and lithium ion battery

A lithium-ion battery, negative electrode material technology, applied in the direction of lithium battery, negative electrode, electrode manufacturing, etc., can solve the problem that the material cycle performance is difficult to meet the application requirements, the grain size is controlled at a suitable size, silicon and lithium silicate grains Large and other problems, to achieve good lithium ion conductivity, good rate performance, and guaranteed performance

Pending Publication Date: 2021-05-14
BTR NEW MATERIAL GRP CO LTD +1
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0005] However, the above three schemes for Li 2 Si 2 o 5 and Li 2 SiO 3 The impact of the grains of lithium silicate on the performance of the material has not been considered, and the crystallization process of lithium silicate will also promote the growth of silicon grains, and the cycle performance of the material is still difficult to meet the application requirements.
[0006] CN107112521A discloses a negative electrode active material, prepared by mixing silicon and lithium silicate, and reducing the grain size of the two by ball milling, etc. The grain size of the latter is controlled at an appropriate size, so the performance of the material needs to be further improved

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  • Negative electrode material, preparation method thereof and lithium ion battery
  • Negative electrode material, preparation method thereof and lithium ion battery
  • Negative electrode material, preparation method thereof and lithium ion battery

Examples

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Embodiment 1

[0052] The present embodiment prepares the negative electrode material according to the following method:

[0053] (1) Take 500 g of silicon oxycarbide coated on the surface with a carbon content of 3% wt, and heat-treat it at 700° C. for 4 hours under an argon atmosphere to obtain silicon dioxide after heat treatment;

[0054] (2) Under an argon atmosphere, the heat-treated silicon oxide and lithium metal are uniformly mixed in a mixing device at a molar ratio of 1.5:1 to obtain silicon oxide containing lithium inside;

[0055] (3) Under an argon atmosphere, sinter the silicon oxide containing lithium at 600° C. for 6 hours, and pickle the sintered product to obtain the negative electrode material.

[0056] The negative electrode materials prepared in this example include nano-silicon, silicon oxide and crystalline Li 2 Si 2 o 5 , the silicon oxide is SiOx, x is 0.2, nano-silicon is uniformly dispersed in SiOx and Li 2 Si 2 o 5 Among them, the average particle diameter ...

Embodiment 2

[0060] The present embodiment prepares the negative electrode material according to the following method:

[0061] (1) Take 500 g of silicon oxycarbide coated on the surface with a carbon content of 3% wt, and heat-treat it at 800° C. for 4 hours under an argon atmosphere to obtain silicon dioxide after heat treatment;

[0062] (2) Under an argon atmosphere, the heat-treated silicon oxide and lithium metal are uniformly mixed in a mixing device at a molar ratio of 1.5:1 to obtain silicon oxide containing lithium inside;

[0063] (3) Under an argon atmosphere, sinter the silicon oxide containing lithium at 600° C. for 6 h, and pickle the sintered product to obtain the final negative electrode material.

[0064] The negative electrode materials prepared in this example include nano-silicon, silicon oxide and crystalline Li 2 Si 2 o 5 , silicon oxide is SiOx, x is 0.3, nano-silicon is uniformly dispersed in SiOx and Li 2 Si 2 o 5 Among them, the average particle size of nan...

Embodiment 3

[0068] The present embodiment prepares the negative electrode material according to the following method:

[0069] (1) Take 300 g of surface-coated silicon oxide with carbon content of 10% wt and heat-treat it at 900° C. for 10 hours under a nitrogen atmosphere to obtain silicon oxide after heat treatment;

[0070] (2) Under a nitrogen atmosphere, the heat-treated silicon dioxide and lithium carbonate are uniformly mixed in a mixing device at a molar ratio of 4:1 to obtain silicon oxide containing lithium inside;

[0071] (3) Under a nitrogen atmosphere, sinter the silicon oxide containing lithium at 800° C. for 8 hours, and pickle the sintered product to obtain the final negative electrode material.

[0072] The negative electrode materials prepared in this example include nano-silicon, silicon oxide and crystalline Li 2 Si 2 o 5 , silicon oxide is SiOx, x is 0.7, nano-silicon is uniformly dispersed in SiOx and Li 2 Si 2 o 5 Among them, the average particle size of nano...

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Abstract

The invention provides a negative electrode material, a preparation method thereof and a lithium ion battery. The negative electrode material comprises nano silicon, silicon oxide and crystalline Li2Si2O5, wherein the grain size of the Li2Si2O5 is less than 20nm. The preparation method comprises the following steps: 1) carrying out heat treatment on a silica material in a protective atmosphere or vacuum to obtain a heat-treated silica material; and 2) in a protective atmosphere, mixing the heat-treated silica material with a lithium source, and sintering in the protective atmosphere to obtain the negative electrode material. According to the negative electrode material provided by the invention, lithium doping is performed on the silica material, so that the first coulombic efficiency of the material is greatly improved, and the cycle performance of the material is improved while the high first coulombic efficiency of the material is finally obtained by controlling the grain size of the generated lithium silicate. The lithium silicate is prepared into a small crystal grain size, so that the lithium ion can smoothly complete the lithium intercalation / deintercalation reaction, and good rate capability is shown.

Description

technical field [0001] The invention belongs to the technical field of energy storage materials, and relates to a negative electrode material, a preparation method thereof and a lithium ion battery. Background technique [0002] As a new type of lithium-ion secondary battery anode material, silicon-oxygen material has become a research hotspot due to its high capacity. However, compared with traditional graphite anode materials, the first Coulombic efficiency of silicon-oxygen materials is lower, and the cycle performance and rate performance are worse, thus limiting its commercial application. [0003] When the silicon-oxygen material is charged for the first time, lithium will be consumed to generate lithium silicate and lithium oxide which are not electrochemically active, resulting in a decrease in its first coulombic efficiency. Therefore, many researchers have improved this problem by pre-supplementing lithium. [0004] CN109155407A discloses a kind of containing SiO...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M4/48H01M4/485H01M10/0525
CPCH01M4/483H01M4/485H01M10/0525Y02E60/10H01M2004/027H01M4/364H01M4/386H01M4/366H01M4/587H01M4/625H01M4/5825H01M4/62H01M10/052H01M4/0471H01M4/48H01M2004/021
Inventor 邓志强屈丽娟庞春雷任建国贺雪琴
Owner BTR NEW MATERIAL GRP CO LTD
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