Negative electrode material, preparation method and application thereof

A negative electrode material and negative electrode technology, applied in the field of negative electrode material and its preparation, can solve the problems of large irreversible capacity, uneven distribution of slurry, and reduce material stability, and achieve the improvement of lithium ion transmission speed, elimination of polarization effect, and method. Simple and easy effects

Pending Publication Date: 2022-02-15
BATTERO TECH CORP LTD
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  • Claims
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AI Technical Summary

Problems solved by technology

However, silicon-oxygen materials have large irreversible capacity and low coulombic efficiency for the first time, which seriously hinders their commercial application; fortunately, researchers have adopted a lithium-supplementing process in advance, and lithium-supplemented silicon-oxygen materials are used as the main battery material It can achieve the same capacity as graphite when the first effect is exerted
However, the residual alkali content on the surface of the lithium-supplemented silicon-oxygen material is relatively high, and it is easy to interact with H in the air. 2 O and CO 2 A chemical reaction occurs that reduces the stability of the material
In addition, the negative electrode homogenate adopts a water-based formula, and the lithium-supplementing silicon-oxygen material will increase the overall pH value of the slurry, and the alkaline environment will promote the reaction of nano-Si particles inside the main material with water to generate H 2 In severe cases, a jelly-like slurry will be formed, which will increase the production cost of the enterprise; at the same time, the residual alkali precipitated in the lithium-supplementing silicon-oxygen material will also destroy some functional groups of the binder, affecting the bonding network of the pole piece, resulting in the slurry being in the pole piece. Uneven distribution on the chip, poor coating effect, and reduced production yield

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  • Negative electrode material, preparation method and application thereof
  • Negative electrode material, preparation method and application thereof
  • Negative electrode material, preparation method and application thereof

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preparation example Construction

[0037]According to another aspect of the present invention, the present invention also relates to the preparation method of described negative electrode material, comprises the following steps:

[0038] Mixing the negative electrode base material, stearic acid and dispersant;

[0039] The negative electrode substrate is a core-shell structure, wherein the inner core includes Si and SiO x , 0.5≤x≤2; the middle layer includes a lithium silicate compound; the shell layer includes carbon.

[0040] A stable lithium-supplementing silicon-oxygen material can be obtained after being uniformly dispersed by a mechanical mixing method.

[0041] Stearic acid is esterified with partially reversible lithium silicate and residual alkali LiOH in the negative electrode substrate at room temperature. The resulting reaction product has certain elasticity and can inhibit the volume expansion of the internal silicon oxide particles together with the carbon coating layer. , to ensure the integrit...

Embodiment 1

[0070] A preparation method of negative electrode material, comprising the following steps:

[0071] (1) Sample SiO after ball milling x Transfer to a tube furnace, pass through Ar to remove the air in the tube, heat to 700°C at a heating rate of 5°C / min, and then maintain a constant temperature for 2 hours; after the heat preservation is completed, change Ar to acetylene gas for CVD deposition, and control the flow rate of acetylene to make the sample The carbon coating content is 3wt%; then the atmosphere in the furnace is changed to Ar, and Si / SiO can be obtained by natural cooling x @C composite material (silicon-oxygen composite material coated with carbon, the same below), denoted as sample S1;

[0072] (2) 50g S1 sample and 10g Li 2 Mix the O powder evenly, transfer it to a tube furnace, pass it into Ar to remove the air in the tube, raise the temperature at 5°C / min to 400°C and keep it for 1 hour to complete the thermal doping lithium supplementation, and obtain lith...

Embodiment 2

[0075] A preparation method of negative electrode material, comprising the following steps:

[0076] (1) Sample SiO after ball milling x Transfer to a tube furnace, pass through Ar to remove the air in the tube, heat to 700°C at a heating rate of 5°C / min, and then maintain a constant temperature for 2 hours; after the heat preservation is completed, change Ar to acetylene gas for CVD deposition, and control the flow rate of acetylene to make the sample The carbon coating content is 1wt%; then the atmosphere in the furnace is changed to Ar, and Si / SiO can be obtained by natural cooling x @C composite material, denoted as sample S1;

[0077] (2) 50g S1 sample and 10g Li 2 Mix the O powder evenly, transfer it to a tube furnace, pass it into Ar to remove the air in the tube, raise the temperature at 5°C / min to 400°C and keep it for 1 hour to complete the thermal doping lithium supplementation, and obtain lithium supplementation silicon oxide material after cooling with the furna...

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Abstract

The invention relates to the technical field of batteries, in particular to a negative electrode material, a preparation method and application thereof. The negative electrode material is of a core-shell structure, wherein the core-shell structure sequentially comprises an inner core, a middle layer, a first protection layer and a second protection layer from inside to outside, the inner core comprises Si and SiOx, x is more than or equal to 0.5 and less than or equal to 2, the middle layer comprises a lithium silicate compound, the first protection layer comprises a carbon material, and the second protection layer comprises lithium stearate. According to the invention, the negative electrode material can fundamentally solve the problem of precipitation of residual alkali on the surface of a lithium supplement type silica material, the lithium stearate protection layer and the carbon coating layer can play a synergistic role, the lithium ion transmission speed of the material is improved, and the polarization effect is eliminated; and the lithium stearate layer has a long-chain hydrophobic group, so that the material can be further prevented from reacting with H2O, and the material stability is improved.

Description

technical field [0001] The invention relates to the technical field of batteries, in particular to a negative electrode material and a preparation method and application thereof. Background technique [0002] With the rapid development of the new energy electric vehicle industry, the market demand for lithium-ion batteries with higher energy density is increasing year by year. Graphite, as the most mature anode material in the current industry, has a theoretical capacity of only 372mAh / g, which is difficult to meet the high requirements of the market. Silicon materials have gradually become another research hotspot in the industry because of their high theoretical capacity (4200mAh / g), high lithium-intercalation platform, rich crustal storage content, and environmental friendliness. However, during the electrochemical cycle, the sharp change in the volume of Si material (400%) will not only lead to the separation of Si from the surrounding conductive carbon network, forming...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M4/62H01M4/36H01M4/38H01M4/48H01M4/13H01M4/134H01M10/0525
CPCH01M4/366H01M4/386H01M4/483H01M4/62H01M4/625H01M4/628H01M4/134H01M4/13H01M10/0525H01M2220/20H01M2004/027Y02E60/10
Inventor 廖星
Owner BATTERO TECH CORP LTD
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