Negative electrode material and preparation method thereof

A negative electrode material and mixed powder technology, which is applied in the field of negative electrode materials and its preparation, can solve the problems affecting the connection between the active material and the current collector in the battery, the decline in the cycle performance of the lithium battery, and the unfavorable capacity of the lithium battery, so as to improve the electrochemical performance. , easy industrial mass production, and the effect of improving cycle stability

Active Publication Date: 2020-01-31
SHANDONG YUHUANG NEW ENERGY TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] However, silicon-based negative electrode materials have serious volume effects during the charging and discharging process of lithium-ion batteries, and the volume expansion rate is 300-400%. However, the gradual pulverization and collapse will affect the connection between the active material and the current collector in the battery, which is not conducive to electron transmission; on the other hand, the volume effect will also gradually thicken the solid electrolyte interface film formed between the silicon-based negative electrode material and the electrolyte. , which is not conducive to improving the capacity of lithium batteries, resulting in a sharp decline in the cycle performance of lithium batteries

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0037] Embodiment 1: Composite material of silicon / iron / carbon

[0038] The composite material of present embodiment silicon / iron / carbon, preparation method is:

[0039] S1, prepare the mixed powder of silicon powder and organic salt:

[0040] S1.1. Weigh 50g of ferric citrate, stir and dissolve in 100mL of 60°C water to obtain ferric citrate solution;

[0041] S1.2, adding 13.5g of silicon powder with a particle size of 100nm to the ferric citrate solution obtained in step (1), stirring at a speed of 1000r / min for 1h, to prepare a mixed solution of silicon powder and ferric citrate;

[0042] S1.3. Stir the mixed solution at a rotational speed of 1000 r / min, and simultaneously heat and dry the mixed solution obtained in step S1.2 at 80° C. to obtain a mixed powder of silicon powder and ferric citrate;

[0043] S2, calcining the mixed powder in protective gas:

[0044] Put the mixed powder of silicon powder and ferric citrate prepared in step S1.3 in a tube furnace, blow nit...

Embodiment 2

[0048] Embodiment 2: Composite material of silicon / iron / carbon

[0049] S1, prepare the mixed powder of silicon powder and organic salt:

[0050]S1.1. Weigh 20g of ferric acetate and 25g of ferric citrate, stir and dissolve in 100mL of 100°C water to obtain ferric citrate solution;

[0051] S1.2, adding 13.5g of silicon powder with a particle size of 50nm to the ferric citrate solution obtained in step (1), stirring at a speed of 2000r / min for 2h, to prepare a mixed solution of silicon powder and ferric citrate;

[0052] S1.3. Spray-dry the mixed solution obtained in step S1.2 at 150° C. to obtain a mixed powder of silicon powder, iron acetate, and iron citrate;

[0053] S2, calcining the mixed powder in protective gas:

[0054] Put the mixed powder of silicon powder, iron acetate and iron citrate prepared in step S1.3 in a tunnel furnace, blow nitrogen, calcinate at 500°C for 6 hours, and collect the sintered phase;

[0055] S3, crushing the product obtained in step S2, an...

Embodiment 3

[0058] Embodiment 3: the composite material of silicon / cobalt, tin / carbon

[0059] Compared with Example 1, the following changes are made:

[0060] (3) 50g ferric citrate of step (1) is changed into 20g cobalt acetate and 20g tin acetate;

[0061] (4 other conditions and steps remain unchanged, and finally a composite material of silicon, cobalt, tin and carbon is obtained.

[0062] With reference to the method of Example 1, when the composite material of silicon / cobalt and tin / carbon obtained is used for the negative electrode sheet of lithium ion battery, the specific capacity of the composite material can reach 882mAh / g, the internal resistance of the battery is 35.4mΩ, and the first Coulombic efficiency reaches 89.6 %, the thickness expansion rate of the fully charged negative electrode is 39.9%; the specific capacity retention rate after 100 cycles is 95.6%.

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PUM

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Abstract

The invention discloses a negative electrode material and a preparation method thereof. The negative electrode material comprises a three-dimensional porous framework and elemental silicon loaded on the three-dimensional porous framework; the three-dimensional porous framework is a composite framework containing metal and carbon; and the metal and the carbon in the three-dimensional porous framework both exist in an elemental form; and the metal is selected from any one or more materials from copper, iron, manganese, cobalt, tin, nickel, magnesium, titanium, aluminum and zinc. According to thenegative electrode material, the composite framework formed by the metal and carbon has excellent toughness and an ordered pore structure, and therefore, the volume effect of the silicon in the intercalation and deintercalation process of lithium ions can be buffered, the structural stability of the negative electrode material is enhanced, and the cycling stability of a negative electrode is improved; and the metal and carbon have excellent conductivity, and when the metal and carbon are compounded with the silicon, the electrochemical performance of the negative electrode material is effectively improved.

Description

technical field [0001] The invention relates to a negative electrode material and a preparation method thereof, belonging to the technical field of battery negative electrodes. Background technique [0002] Due to its high working voltage, high specific energy, small size, light weight, and long cycle life, lithium-ion batteries have become the research focus of the battery industry, especially the focus of the development and competition of the automobile industry. Among them, the negative electrode is an important part of the lithium-ion battery, which affects the specific energy and cycle life of the lithium-ion battery. [0003] Traditional commercial lithium-ion batteries mainly use graphite-like carbon materials as negative electrode materials. The theoretical specific capacity of this graphite negative electrode is only 372mAh / g, which is difficult to meet the needs of use. The theoretical specific capacity of silicon-based negative electrode materials is as high as ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M4/38H01M4/62H01M10/0525
CPCH01M4/386H01M4/625H01M4/626H01M4/628H01M10/0525H01M2004/021H01M2004/027Y02E60/10
Inventor 张立君陈慧龙段恒志王念贵王瑛
Owner SHANDONG YUHUANG NEW ENERGY TECH
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