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Hollow porous micron-scale silicon sphere, silicon-based negative electrode material and preparation method of lithium ion battery

A silicon-based negative electrode material, lithium-ion battery technology, applied in the manufacture of electrolyte batteries, battery electrodes, secondary batteries, etc., can solve problems such as the inability to fundamentally suppress the volume effect, the pulverization and shedding of electrode electroactive materials, and volume expansion. , to solve the problem of cyclic charge and discharge life, eliminate pulverization and shedding, and inhibit volume expansion and contraction.

Active Publication Date: 2017-09-12
WUHU LION AUTOMOTIVE TECH CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, the silicon negative electrode is accompanied by serious volume expansion and contraction during the process of intercalating and removing lithium, which leads to the powdering and falling off of the electroactive material on the electrode, and finally leads to capacity fading.
The development of silicon-containing composite materials has gradually become the focus of people's research. The research idea is generally to form alloys of silicon and other inactive metals (such as Fe, Al, Cu, etc.). Carbon composite materials are used to prepare lithium-ion battery negative electrodes, or silicon materials are evenly dispersed into other active or inactive materials to form composite materials, such as Si-C, Si-TiN and other lithium-ion battery negative electrodes widely used in the prior art. Capacitive silicon-carbon composite materials. Although these existing silicon-based composite materials can improve their cycle stability and capacity fading as lithium-ion battery negative electrodes to a certain extent, their mechanisms are simple physical composite or high-temperature carbon coating. , can not fundamentally suppress the volume effect in the process of charge and discharge, after many cycles, the capacity will begin to decay rapidly

Method used

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  • Hollow porous micron-scale silicon sphere, silicon-based negative electrode material and preparation method of lithium ion battery

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preparation example Construction

[0029] First of all, the present invention provides a method for preparing hollow porous micron-sized silicon spheres. The method includes two major steps of metallothermic reduction and pickling to remove oxides. The specific steps are as follows:

[0030] Step 1, metallothermic reduction of hollow glass microspheres. Mix active metal powder and hollow glass microspheres 1 evenly according to a certain ratio, then transfer to a crucible, heat up to the thermal reduction reaction temperature under argon protection or vacuum conditions, keep warm for a certain period of time, and cool naturally to obtain active metal oxides / silicon / silicon dioxide composite, i.e. as attached figure 1 As shown in , hollow silicon spheres 4 embedded by metal oxide 2 are obtained. In the above-mentioned heat-reduced hollow glass microspheres, the particle size of the hollow glass microspheres is 3-100 μm, preferably 3-50 μm, and the active metal used includes metal aluminum, metal magnesium, met...

Embodiment 1

[0038] Preparation and performance testing of hollow porous micron-sized silicon spheres:

[0039] (1) Metal thermal reduction

[0040] Weigh 0.7 grams of lithium powder and 2.0 grams of hollow glass microspheres (particle size 3 microns), grind them evenly in an agate mortar in an argon glove box, transfer them to an alumina crucible, and then transfer them to a tube furnace, argon Heat up to 500°C under air protection and keep warm for 0.5 hour to get composite powder.

[0041] (2) Acid corrosion to remove oxides

[0042] Add the composite powder material obtained in step (1) into 20 mL of pure acetic acid, stir for 2 hours, filter, wash with water, and dry to obtain hollow porous micron-sized silicon spheres.

[0043] (3) Capacity test

[0044] The obtained hollow porous micron-sized silicon sphere material was mixed with conductive agent acetylene black and binder PVDF (polyvinylidene fluoride) according to the mass ratio of 80: 10: 10, and NMP (1-methyl-2-pyrrolidone) ...

Embodiment 2

[0046] Preparation and performance testing of hollow porous micron-sized silicon spheres:

[0047] (1) Metal thermal reduction

[0048] Weigh 0.9 grams of aluminum powder and 1.8 grams of hollow glass microspheres (particle size 10 microns), grind them evenly in an agate mortar, transfer them to an alumina crucible, and then transfer them to a tube furnace, and raise the temperature to 800 °C under the protection of argon. degree, heat preservation for 4 hours to obtain composite powder.

[0049] (2) Acid corrosion to remove oxides

[0050] Add the composite powder material obtained in step (1) into 100 mL of 10% hydrochloric acid solution, stir for 12 hours, filter, wash with water, and dry to obtain hollow porous micron-sized silicon spheres.

[0051] (3) Capacity test

[0052] The obtained hollow porous micron-sized silicon sphere material was mixed with conductive agent acetylene black and binder PVDF (polyvinylidene fluoride) according to the mass ratio of 80: 10: 10, ...

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Abstract

The invention provides a preparation method of hollow porous micron order silicon spheres, a silicon-based cathode material and a lithium ion battery. The preparation method comprises the following steps: reducing hollow glass beads by using active metals; then removing metal oxides by acid to obtain the hollow porous micron order silicon spheres; and preparing the silicon-based negative electrode and the lithium ion battery based on the hollow porous micron order silicon spheres. As the prepared hollow porous micron order silicon spheres have a lot of holes and pores in the porous walls and in the spheres, the specific discharge capacity of the battery is greatly improved, and volume explanation and shrinkage in a lithium insertion / extraction process are fully inhibited by means of the holes and pores in the porous walls and in the spheres. Moreover, as the spherical structures are very stable, pulverizing and falling phenomena of the electric active substances can be eliminated, so that the service life of the silicon-based cathode material is prolonged. The synthetic method of the hollow porous micron order silicon spheres is simple and the technical problem of capacity and service life of the high-capacity lithium ion battery is effectively solved.

Description

technical field [0001] The present invention relates to the preparation technology of lithium-ion battery negative electrode materials, in particular to a method for preparing hollow porous micron-sized silicon spheres, a method for preparing silicon-based negative electrode materials based on the hollow porous micron-sized silicon spheres, and a silicon-based negative electrode based on the described silicon-based negative electrode materials. Materials for the preparation of lithium-ion batteries. Background technique [0002] At present, the lithium-ion batteries used in production mainly use graphitized carbon as the negative electrode material, but the lithium storage capacity of the material is not high. As far as graphite-based negative electrode materials are concerned, their large layered structure voids not only provide a place for lithium storage, but also determine the characteristics of the material's low theoretical specific capacity (about 372mAh / g). Therefor...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H01M4/134H01M4/1395
CPCH01M4/386H01M10/0525H01M10/058Y02E60/10
Inventor 曾绍忠王秀田赵志刚陈效华
Owner WUHU LION AUTOMOTIVE TECH CO LTD
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