Method for preparing silicon-iron powder through zinc-bismuth alloy coated magnesium-silicon-iron particles and silicon-iron composite powder

A magnesium-iron-silicon and bismuth alloy technology, applied in metal processing equipment, transportation and packaging, coating and other directions, can solve the problems of not forming nano-porous silicon morphology, unable to solve the problem of using crystalline silicon, etc., to reduce surface oxidation and ignition risk, elimination of powder overburning problems, uniformity of micropore voids

Active Publication Date: 2018-05-08
GUILIN ELECTRICAL EQUIP SCI RES INST
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

This method uses the carbon coating layer and the silicon-iron phase as a buffer layer to alleviate the volume expansion of silicon during charge and discharge, but does not form nanoporous silicon morphology, which cannot solve the problem of using crystalline silicon as a negative electrode.

Method used

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  • Method for preparing silicon-iron powder through zinc-bismuth alloy coated magnesium-silicon-iron particles and silicon-iron composite powder
  • Method for preparing silicon-iron powder through zinc-bismuth alloy coated magnesium-silicon-iron particles and silicon-iron composite powder
  • Method for preparing silicon-iron powder through zinc-bismuth alloy coated magnesium-silicon-iron particles and silicon-iron composite powder

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preparation example Construction

[0068] The preparation method of the embodiment of the present invention is not limited to the smelting, mixing and ball milling, heat treatment, and pickling methods described above, and can also be completed by methods known to those skilled in the art, and the ball milling medium in the powder crushing process is not limited to asphalt Acetone solution, asphalt tetrahydrofuran solution, polyvinyl alcohol aqueous solution and polyimide (PI) / N-methylpyrrolidone (NMP) solution, etc., can also add organic polymer compounds known to those skilled in the art to form on the surface of ferrosilicon powder Obtain a certain carbon conductive layer.

[0069]According to another aspect of the embodiments of the present invention, there is also provided a foamed ferrosilicon powder, which includes ferrosilicon powder particles, the ferrosilicon powder particles have a plurality of microporous structures, and the micropore size is 2 nm to 100 nm. The primary particle size of ferrosilicon...

Embodiment 1

[0075] (1) Choose a small vacuum furnace, according to the capacity of the smelting graphite crucible, prepare ferrosilicon powder and magnesium block at a weight ratio of 1:0.85 per furnace, heat the ingredients to 800°C in a vacuum atmosphere, and keep the temperature for 60 minutes to obtain magnesium silicon Iron composite particles;

[0076] (2) Under a dry air atmosphere, use a jaw crusher to roughly crush the magnesium-silicon-iron composite particles to a particle size of less than 5mm, then vibrate and ball mill under the protection of a nitrogen atmosphere, sieve and classify, and make magnesium-iron-silicon composite powder;

[0077] (3) Select 20-300 mesh magnesium-iron-silicon composite powder, preferably 200 grams of magnesium-silicon-iron composite powder with a particle size of 40-100 mesh, and equip 1000 grams of coated metal powder in a ratio of 1:5. The coated metal powder is preferably It is formed by mixing 50 grams of metal zinc powder with a particle siz...

Embodiment 2

[0087] (1)(2) is identical with embodiment one;

[0088] (3) The preferred particle size is 200 grams of magnesium-silicon-iron composite powder of 100-200 mesh, equipped with 800 grams of coated metal powder in a ratio of 1:4, and the coated metal powder preferably consists of 50 grams of metal zinc powder and metal powder with a particle size of less than 100 mesh Mix 750 grams of bismuth powder, put the above-mentioned silicon-iron-magnesium compound and coated metal powder into a stainless steel tank with a diameter of 185mm, and mix in cemented carbide balls 2-4 times the weight of the above-mentioned mixed powder. The diameter of the ball is 6-12mm, and it is filled with nitrogen or argon to protect the seal, and it is mixed and milled for 32 hours with a common rolling ball mill;

[0089] (4) same as embodiment one;

[0090] (5) same as embodiment one;

[0091] (6) The obtained powder after the diffusion heat treatment is packed into a tubular vacuum furnace, and the ...

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Abstract

The invention discloses a method for preparing foam-shaped silicon powder through zinc-bismuth alloy coated magnesium-silicon-iron particles. The method comprises the steps that magnesium-silicon-ironcomposite powder is prepared; the surface of the magnesium-silicon-iron composite powder is coated with a zinc-bismuth alloy layer; the magnesium-silicon-iron composite powder coated with the zinc-bismuth alloy layer is subjected to solid-phase diffusion heat treatment to promote zinc and bismuth metal in the coating layer to conduct reaction combination with magnesium and silicon; the magnesium-silicon-iron composite powder subjected to solid-phase diffusion heat treatment is subjected to oxidation treatment; and the magnesium-silicon-iron composite powder subjected to oxidation treatment issubjected to acid pickling to remove zinc, bismuth and magnesium. By adopting the zinc-bismuth alloy coated magnesium-silicon-iron composite particles not likely to be oxidized and with the melting point being lower than the ignition point of magnesium and by combining with the solid-phase diffusion treatment and low-oxygen oxidation treatment processes under a certain temperature, the foam silicon powder with a micropore structure is obtained, the preparation efficiency is improved, and the primary particle size of the foam silicon powder is small.

Description

technical field [0001] The present invention relates to a method for preparing foamy ferrosilicon powder, in particular to a method for preparing foamy ferrosilicon powder coated with zinc-bismuth alloy magnesium ferrosilicon particles, and also to a foamy ferrosilicon composite powder prepared by the method . Background technique [0002] Since silicon has a theoretical specific capacity (4200mAh / g) more than ten times higher than that of graphite anode, the use of silicon to replace the commonly used graphite anode has become the goal of high energy density power battery research. As a negative electrode, silicon has the disadvantages of large volume expansion, silicon particle breakage, pulverization, low coulombic efficiency for the first charge and discharge, and high impedance; in response to the above shortcomings, a series of improvement methods have been proven effective, such as the use of nanoscale silicon particles It can reduce the breakage of bulk silicon, the...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B22F9/16B22F1/02B22F1/00
CPCB22F1/0007B22F9/16B22F1/142B22F1/17
Inventor 王振宇朱凌云张天锦王奐然赵霞妍
Owner GUILIN ELECTRICAL EQUIP SCI RES INST
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