Negative electrode active material, and preparation method and application thereof

A negative electrode active material, nano-silicon technology, applied in the direction of negative electrodes, nanotechnology for materials and surface science, active material electrodes, etc., can solve the problem of easy stacking of Mxene materials, affecting the performance of composite materials, and poor point-surface contact to achieve excellent mechanical properties, promote de-embedding and embedding, and high elastic modulus

Inactive Publication Date: 2020-12-04
HUI ZHOU BTR NEW MATERIAL TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] An existing silicon-Mxene composite anode material with a core-shell structure is used to disperse silicon and Mxene materials through mechanical high-energy ball milling. This method realizes the combination of silicon and

Method used

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

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preparation example Construction

[0087] Another embodiment of a method for preparing a negative electrode active material, the process flow chart of the preparation method can be found in Figure 5 , the method includes the following steps S100-S300:

[0088] Step S100: preparing lamellar Mxene material

[0089] Specifically, the preparation method of the lamellar Mxene material is: the Mxene material is mixed with an organic polymer solvent, and the layer expansion treatment is performed to obtain the lamellar Mxene material;

[0090] In this embodiment, the Mxene material is expanded to obtain a lamellar Mxene material with a low number of layers, which is beneficial to the surface layer adhesion of nano-silicon;

[0091] In some embodiments, the preparation method also includes the step of ultrasonic dispersion after layer expansion treatment; layer expansion and ultrasonic dispersion can even obtain a layered Mxene material with good dispersion, and the composite combination with nano-silicon has a good ...

Embodiment 1

[0147] (1) The ceramic phase precursor MAX raw material (Ti 3 AlC 2 ) immersed in the HCl+LiF mixed etchant for stirring etching, the stirring time is 15min, the stirring rate is 800rpm, the mass volume ratio of LiF and HCl is 1:15g / mL, the addition amount of the ceramic phase precursor MAX The mass ratio to LiF is 1:1.05 to obtain Mxene material;

[0148] (2) The Mxene material is added in a mixed solvent of chloroform and ethanol, wherein chloroform: the mass ratio of ethanol is 10:1, and the mass ratio of the Mxene material to chloroform is 0.5:5, using a stirrer to stir, stirring frequency Be 30Hz, stirring time 2h, then add deionized water and carry out the ultrasonic treatment that frequency is 15Hz, the mass ratio of described Mxene material and deionized water is 1:20, ultrasonic time is 5h, obtains lamellar Mxene material; The number of sheets of the lamellar Mxene material is a single layer;

[0149] (3) The purity is 99.9%, the median particle diameter is 50nm, a...

Embodiment 2

[0155] (1) The ceramic phase precursor MAX raw material (Ti 3 AlC 2 ) immersed in the HCl+LiF mixed etchant for stirring etching, the stirring time is 5min, the stirring rate is 200rpm, the mass volume ratio of LiF and HCl is 1:10g / mL, the addition amount of the ceramic phase precursor MAX The mass ratio with LiF is 1:1.05, and the Mxene material is obtained;

[0156] (2) Add the obtained Mxene material to a mixed solvent of chloroform and ethanol, wherein chloroform: the mass ratio of ethanol is 1:5, the mass ratio of the Mxene material to chloroform is 1:8, and the stirring frequency is 30Hz for 3h , then add deionized water and carry out ultrasonic treatment with a frequency of 15Hz, the mass ratio of the Mxene material to deionized water is 1:20, and the ultrasonic time is 5h to obtain the lamellar Mxene material; the lamellar Mxene material The average number of layers is 5 layers;

[0157] (3) The purity is 99.9%, the median particle diameter is 30nm, and the specific...

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Abstract

The invention relates to a negative electrode active material as well as a preparation method and application thereof. The negative electrode active material comprises an inner core and a carbon coating layer formed on the surface of the inner core, the inner core comprises nanometer silicon and a lamellar Mxene material, and the nanometer silicon is distributed on the surface of the lamellar Mxene material and/or between lamellas. The lamellar Mxene material disclosed by the invention is tightly combined with silicon and also has excellent combinability with a carbon coating layer, so that the conductivity of the silicon can be effectively improved, and de-intercalation and intercalation of lithium ions in the silicon are promoted; in addition, the lamellar Mxene material disclosed by theinvention is beneficial to surface layer adhesion of nano silicon, so that the nano silicon is uniformly dispersed in an Mxene material lamella; and finally, the lamellar Mxene material is combined with the carbon coating layer, so that excellent mechanical properties are achieved, and the stability of a composite structure is improved.

Description

technical field [0001] The invention belongs to the technical field of batteries, and in particular relates to a negative electrode active material, its preparation method and application. Background technique [0002] Lithium-ion batteries are one of the energy storage devices that will be developed in the future, and are also the core components of power vehicles. With the rapid development of the new energy market, people's requirements for power vehicles are getting higher and higher, which requires the power battery as the core component to have higher energy density and better cycle performance. At present, commercial lithium-ion batteries mainly use graphite-based negative electrode materials, but its theoretical specific capacity is only 372mAh / g, which cannot meet the demand for high energy density of lithium-ion batteries in the future. The theoretical capacity of silicon negative electrode is as high as 4200mAh / g, which is ten times that of graphite material, and...

Claims

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Application Information

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IPC IPC(8): H01M4/36H01M4/38H01M4/58H01M4/583H01M4/62H01M4/13H01M10/0525B82Y30/00
CPCH01M4/366H01M4/386H01M4/58H01M4/583H01M4/625H01M4/13H01M10/0525B82Y30/00H01M2004/027Y02E60/10
Inventor 肖称茂何鹏任建国贺雪琴杜宁杨德仁
Owner HUI ZHOU BTR NEW MATERIAL TECH
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