Lithium ion battery composite negative electrode material and preparation method thereof

A technology for lithium-ion batteries and negative electrode materials, applied in battery electrodes, secondary batteries, nanotechnology for materials and surface science, etc., can solve the problems of easy oxidation and abnormality of nano-silicon, and achieve high controllability, Improved storage performance and good mechanical properties

Inactive Publication Date: 2018-04-06
CENT SOUTH UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0007] Aiming at the above-mentioned technical problems in the related art, the present invention proposes a composite negative electrode material for lithium-ion batteries, which can utilize the native oxide layer on the surface of the nano-silicon material, and perform an in-situ chemical reaction on the surface of the nano-silicon by pre-adding a lithium source to generate a layer of silicon. Lithium acid coating layer can greatly improve the stability of the interface between nano-silicon and electrolyte, and at the same time, it can alleviate the damage of the electrode due to the volume change of silicon. The preparation process is simple and controllable, which solves the problems of easy oxidation of nano-silicon and abnormal capacity.

Method used

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  • Lithium ion battery composite negative electrode material and preparation method thereof
  • Lithium ion battery composite negative electrode material and preparation method thereof
  • Lithium ion battery composite negative electrode material and preparation method thereof

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0055] After 0.8 g of nano-silicon particles were placed in humid air for one week, the nano-silicon was dissolved in 50 mL of deionized water at 10°C. Then add 0.05g of lithium carbonate, stir evenly, disperse ultrasonically, control the temperature to be constant during the process, and then freeze-dry the solution to obtain the precursor.

[0056] The obtained precursor was placed in an argon atmosphere tube furnace, heated to 900°C at 5°C / min, kept at a constant temperature for 2h, and cooled naturally to obtain a nano-silicon material coated with lithium silicate.

[0057] Subsequently, the nano-silicon material coated with lithium silicate is washed with deionized water, centrifuged at a high speed, and vacuum-dried to obtain a lithium-ion battery composite negative electrode material.

[0058] The physical and chemical performance characterization of the obtained lithium-ion battery composite negative electrode material is shown in figure 1 , figure 2 , image 3 . ...

Embodiment 2

[0060] Take 0.5g of nano-silicon and add 50ml of 10% hydrogen peroxide, stir and ultrasonically disperse, filter and dry in vacuum at 80°C. At room temperature, dissolve the treated nano-silicon in 50ml of ethanol, stir and ultrasonically disperse, add 0.5g of anhydrous lithium acetate, continue to stir and ultrasonically disperse uniformly for 1h. The solution was then freeze-dried to obtain the precursor.

[0061] The obtained precursor was placed in an argon atmosphere tube furnace, heated to 700°C at 5°C / min, kept at a constant temperature for 5h, and cooled naturally to obtain nano-silicon materials coated with lithium silicate and carbon layers.

[0062] Subsequently, the nano-silicon material coated with lithium silicate and carbon layer is washed with deionized water, centrifuged at a high speed, and vacuum-dried to obtain a lithium-ion battery composite negative electrode material.

[0063] The microstructure characterization of the obtained lithium-ion battery compo...

Embodiment 3

[0065] Take nano-silicon and add 50ml of 10% hydrogen peroxide, stir and ultrasonically disperse, filter and dry in vacuum at 80°C. At room temperature, the treated nano-silicon and lithium oxalate were mixed in a mass ratio of 2:1. The mixture was milled in a high-speed vibrating ball mill at 1200 rpm for 3 h to obtain a precursor.

[0066] The obtained precursor was placed in an argon atmosphere tube furnace, heated to 900°C at 5°C / min, kept at a constant temperature for 5h, and cooled naturally to obtain a nano-silicon material coated with lithium silicate.

[0067] Subsequently, the nano-silicon material coated with lithium silicate is washed with deionized water, and vacuum-dried after high-speed centrifugation to obtain a lithium-ion battery composite negative electrode material.

[0068] Figure 6 It is the XRD spectrum of the obtained lithium-ion battery composite negative electrode material. The results show that the lithium-ion battery composite negative electrode ...

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Abstract

The invention discloses a lithium ion battery composite negative electrode material and a preparation method thereof. The surface of nanometer silicon is subjected to oxidization treatment to obtain nanometer silicon coated with silicon dioxide on the surface; the nanometer silicon coated with silicon dioxide on the surface is mixed with a lithium source uniformly to obtain a precursor; and the obtained precursor is placed into inert gas to be heated to obtain a nanometer silicon material coated with lithium silicate, and the product is subjected to washing, centrifugal separating and drying to obtain the lithium ion battery composite negative electrode material. By taking a uniform primary oxide layer on the surface of the nanometer silicon material as the substrate, an in-situ chemical reaction is performed to realize uniform coating of lithium silicate, so that stability between nanometer silicon and air or an electrolyte interface is improved effectively, thereby greatly improvingelectrochemical performance of the nanometer silicon material.

Description

technical field [0001] The invention relates to the technical field of lithium ion battery material preparation, in particular to a lithium ion battery composite negative electrode material and a preparation method thereof. Background technique [0002] With the development of human society, the energy crisis and environmental issues have increasingly become the focus of attention. The clean and efficient use of traditional energy and the development of new energy technologies have become the main trend. Lithium-ion batteries have high performance, safety and environmental protection It is currently the most promising high-energy green secondary battery for development and application prospects. However, in recent years, the demand for battery energy density in various fields has increased rapidly. In particular, the country has accelerated the promotion and application of new energy vehicles, and new high-energy Density batteries have become a hot spot in current research a...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M4/36H01M4/38H01M4/62H01M4/134H01M10/0525B82Y30/00
CPCB82Y30/00H01M4/134H01M4/366H01M4/386H01M4/624H01M4/628H01M10/0525Y02E60/10
Inventor 郭华军周玉李新海王志兴彭伟佳王接喜彭文杰胡启阳
Owner CENT SOUTH UNIV
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