High capacity porous silicon material, preparation method and application thereof

A porous silicon, high-capacity technology, applied in the field of material science, can solve the problems of unfavorable high theoretical specific capacity, oxidation, and lower specific capacity of porous silicon, and achieve simple process, avoid oxidation, improve specific capacity and cycle stability Effect

Active Publication Date: 2016-08-10
浙江锂宸新材料科技有限公司
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

However, since magnesium silicide is decomposed at high temperature in the air, the decomposed silicon will inevitably be oxidized, which will reduce the specific capacity of porous silicon, which is not conducive to taking advantage of the high theoretical specific capacity of silicon.

Method used

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  • High capacity porous silicon material, preparation method and application thereof
  • High capacity porous silicon material, preparation method and application thereof
  • High capacity porous silicon material, preparation method and application thereof

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0026] 1) The magnesium silicide is heat-treated at 600° C. for 20 hours, and excessive high-purity nitrogen is used as the reaction gas during the heat treatment.

[0027] 2) Treat the product obtained in step 1) in a hydrochloric acid solution of a certain concentration for 10 hours, where the concentration of hydrochloric acid is 0.5 mol / L, wash it with deionized water 5 times after acid treatment, then centrifuge, and finally vacuum dry.

[0028] The relevant characterization results of the porous silicon prepared in this example are as follows figure 1 Shown. It can be seen from the figure that the particle size distribution of this porous silicon is narrow, the pore size is nanometer, the pore distribution is uniform, the particles are pure silicon, and the oxygen content is so low that the scanning electron microscope energy spectrometer (EDS) cannot detect oxygen.

[0029] The porous silicon prepared in this example was made into a button cell for performance testing, and the...

Embodiment 2

[0031] 1) The magnesium silicide is heat-treated at 700° C. for 15 hours, and excessive high-purity nitrogen is used as the reaction gas during the heat treatment.

[0032] 2) Treat the product obtained in step 1) in a hydrochloric acid solution of a certain concentration for 5 hours, where the concentration of hydrochloric acid is 2.0 mol / L, wash it with deionized water 7 times after acid treatment, then centrifuge, and finally vacuum dry.

[0033] The relevant characterization results of the porous silicon material prepared in this example are the same as figure 1 similar.

[0034] The porous silicon prepared in the examples was made into a button cell for performance testing, and the cycle specific capacity curve and the coulombic efficiency were obtained as image 3 Shown. It can be seen from the figure that the porous silicon prepared by this process not only has a higher initial capacity, but after 15 cycles, its capacity is still much higher than that of ordinary porous silico...

Embodiment 3

[0036] 1) The magnesium silicide is heat-treated at 800° C. for 10 hours, and excessive high-purity nitrogen is used as the reaction gas during the heat treatment.

[0037] 2) Treat the product obtained in step 1) in a hydrochloric acid solution of a certain concentration for 2 hours, where the concentration of hydrochloric acid is 5 mol / L. After acid treatment, it is washed with deionized water 8 times, centrifuged, and finally vacuum dried.

[0038] The relevant characterization results of the porous silicon material prepared in this example are the same as figure 1 similar.

[0039] The porous silicon prepared in the examples was made into a button cell for performance testing, and the cycle specific capacity curve and the coulombic efficiency were obtained as Figure 4 Shown. It can be seen from the figure that the porous silicon prepared by this process not only has a higher initial capacity, but after 15 cycles, its capacity is still much higher than that of ordinary porous si...

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Abstract

The invention discloses a preparation method of a high capacity porous silicon material. The method is characterized by specifically including: placing magnesium silicide powder in nitrogen atmosphere, conducting 600-800DEG C heat treatment, then performing pickling and aftertreatment to obtain the porous silicon material with high capacity. The preparation method of the high capacity porous silicon material provided by the invention uses nitrogen atmosphere to replace air atmosphere, avoids oxidation of silicon at the same time of porous silicon preparation, and has no need of high volatility hydrofluoric acid to conduct treatment, and the process is simple, efficient and environment-friendly. The prepared porous silicon has very low oxygen content, can be applied as a negative electrode material in a lithium ion battery to remarkably improve the specific capacity and cycle stability of the lithium ion battery.

Description

Technical field [0001] The invention belongs to the field of materials science, and specifically relates to a high-capacity porous silicon material and a preparation method and application thereof. Background technique [0002] Lithium-ion battery, referred to as lithium battery, is a rechargeable battery with high energy density. The charging and discharging cycle of lithium batteries is realized by the continuous insertion and extraction of lithium ions between the positive and negative materials. Therefore, the lithium battery is also called the rocking chair battery. The unit energy density of lithium batteries is very high, the charging speed is very fast, and the cycle performance is excellent, making it widely used in many aspects of modern life and production. [0003] Since the advent of lithium-ion batteries, due to the efforts of researchers, many types of materials suitable as negative electrodes of lithium-ion batteries have been discovered. However, due to various re...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M4/38H01M10/0525C01B33/021
CPCC01B33/021H01M4/386H01M10/0525Y02E60/10
Inventor 杜宁张亚光张辉杨德仁
Owner 浙江锂宸新材料科技有限公司
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