Porous silicon/graphite composite electrode material with low expansion rate and preparation method thereof

A low expansion rate, composite electrode technology, applied in battery electrodes, batteries, circuits, etc., can solve the problems of increasing material cost, electrode expansion, volume expansion, etc., and achieve the effect of increasing capacity, improving conductivity, and low expansion rate

Inactive Publication Date: 2017-05-31
山东泰纳新材料科技有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, the above-mentioned technology has the following disadvantages: firstly, as a means of high energy consumption and low productivity, the ball milling method will greatly increase the cost of materials
[0017] (1) First, the silicon particles are still attached to the surface of the graphite ball. When the silicon particles expand, the volume of the entire particle will still expand, resulting in the expansion of the entire electrode.

Method used

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  • Porous silicon/graphite composite electrode material with low expansion rate and preparation method thereof
  • Porous silicon/graphite composite electrode material with low expansion rate and preparation method thereof
  • Porous silicon/graphite composite electrode material with low expansion rate and preparation method thereof

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0053] (1) Preparation of alloy silicon spheres

[0054] Set the silicon content to 20% (such as figure 1 Shown) the aluminum-silicon alloy is sprayed, and the alloy ball with a diameter of 5 microns is obtained by controlling the ratio of the air flow and the material in the spraying process.

[0055] (2) Dealloying of alloy balls

[0056] Put the alloy balls obtained in step (1) into hydrochloric acid with a concentration of 1mol / L, and after corroding for 5 hours, filter the obtained solution, and dry the obtained powder to obtain porous silicon balls (such as figure 2 shown).

[0057] (3) Carbon coating of porous silicon spheres and mixing with graphite

[0058] Put the silicon spheres obtained in step (2) into CVD, pass through argon to evacuate, pass through methane and carbon dioxide to heat to 900 degrees Celsius, keep warm for ten minutes, and cool to room temperature to obtain graphene-coated porous silicon (such as image 3 Shown), porous silicon and graphite a...

Embodiment 2

[0060] (1) Preparation of alloy silicon spheres

[0061] Spray a magnesium-silicon alloy with a silicon content of 20%, and obtain alloy balls with a diameter of 10 microns by controlling the ratio of the air flow to the material during the spraying process.

[0062] (2) Dealloying of alloy balls

[0063] Put the alloy balls obtained in step (1) into sulfuric acid with a concentration of 5 mol / L, corrode for 10 hours, filter the obtained solution, and dry the obtained powder to obtain porous silicon balls.

[0064] (3) Carbon coating of silicon spheres and mixing with graphite

[0065] Put the silicon spheres obtained in step (2) into the sucrose solution, stir and mix thoroughly, then spray-dry the obtained solution, and carbonize the obtained sample under the protection of argon, the carbonization temperature is 500 degrees Celsius, and the time is 6 hours . The obtained amorphous carbon-coated porous silicon (such as Figure 4 shown) and graphite were added into the aqu...

Embodiment 3

[0067] (1) Preparation of alloy silicon spheres

[0068] The magnesium-silicon alloy with a component content of 5:95 is sprayed, and alloy balls with a diameter of 400 nanometers are obtained by controlling the ratio of air flow and material during the spraying process.

[0069] (2) Dealloying of alloy balls

[0070] Put the alloy balls obtained in step (1) into hydrochloric acid with a concentration of 1mol / L, corrode for 5 hours, filter the obtained solution, and dry the obtained powder to obtain porous silicon balls.

[0071] (3) Carbon coating of silicon spheres and mixing with graphite

[0072] The porous silicon and graphite obtained in step (2) are added to a low-speed ball mill in a weight ratio of 5:95 for thorough mixing (such as Figure 6 shown).

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Abstract

The invention discloses a porous silicon/graphite composite electrode material with low expansion rate and a preparation method thereof. The porous silicon/graphite composite electrode material is characterized in that porous silicon is prepared by a dealloying technology, so as to prepare nanometer silicon at low cost; by utilizing carbon coating, the conductivity and stability of the porous silicon are improved; the porous silicon is uniformly mixed with a graphite anode material according to a certain ratio, so as to prepare and design the porous silicon/graphite composite anode material. The porous silicon/graphite composite electrode material has the advantages that the space in the porous silicon can provide enough space for the expansion of silicon, so as to realize the low expansion rate of whole silicon and carbon anode, and ensure the low expansion rate of the electrode and the safety of a battery; the silicon is coated with carbon, and the carbon comprises graphite, amorphous cracking carbon and the like, so that the conductivity and stability of the porous silicon are improved; by adopting the low-cost dealloying method, the costs of silicon and whole composite anode are low.

Description

technical field [0001] The invention relates to the field of preparation of silicon / graphite composite negative electrode materials for lithium-ion batteries, in particular to a porous silicon / graphite composite electrode material with low expansion rate during charging and discharging and a preparation method thereof. Background technique [0002] At present, the commercial lithium-ion battery is a secondary battery system that uses graphite as the negative electrode and a lithium-containing compound as the positive electrode, and the positive and negative electrodes are separated by a separator to form a continuous charge-discharge secondary battery system. [0003] During the charging process, lithium ions deintercalate from the positive electrode, pass through the electrolyte and separator, reach the negative electrode, and form C with graphite. 6 Li compounds, during the discharge process, lithium ions are deintercalated from the negative electrode and pass through the ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M4/36H01M4/38H01M4/587H01M4/62H01M10/0525
CPCH01M4/364H01M4/366H01M4/386H01M4/587H01M4/625H01M4/628H01M10/0525H01M2220/20Y02E60/10
Inventor 慈立杰翟伟邵学智
Owner 山东泰纳新材料科技有限公司
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