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A high purity and high crystallinity moo 2 preparation method

A h24mo7n6o24·4h2o, silicon powder technology, applied in the field of materials, can solve problems such as hindering battery rate performance, electrode capacity attenuation, limiting high specific capacity, etc., achieve good cycle stability and rate performance, less side reactions, and high product purity Effect

Active Publication Date: 2021-02-19
WUHAN UNIV OF TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] In the field of LIBs, anode materials are often plagued by large strain and low conductivity when performing electrochemical tests, resulting in rapid electrode capacity decay and hindering the rate performance of the battery.
Most electrode materials generally have low conductivity, for example: silicon electrodes have 4200mAhg -1 The ultra-high theoretical specific capacity, but its electrical conductivity is very low, and the structure is easy to collapse during the intercalation of lithium ions, which limits the release of its high specific capacity.
However, MoO 2 Almost no problem of low conductivity, bulk MoO 2 The resistivity at 300K is 8.8×10 -5 Ω·cm, belonging to the range of conductors

Method used

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  • A high purity and high crystallinity moo <sub>2</sub> preparation method

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Experimental program
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Effect test

Embodiment 1

[0031] Preparation of high-purity and high-crystallinity MoO 2 ,Proceed as follows:

[0032] 1) Preparation of Si / H 24 Mo 7 N 6 o 24 4H 2 O: Weigh 1g of silicon powder (submicron, average particle size is 100nm, purity>99.9%, specific surface area is 8.30m 2 / g, the bulk density is 1.89g / cm 3 , the crystal form is spherical) into a beaker filled with 200mL of absolute ethanol, and stirred at room temperature for 12h with a magnet until uniformly dispersed. Then add 1g ammonium molybdate tetrahydrate (H 24 Mo 7 N 6 o 24 4H 2 O), continue to stir with the magnet for 12h, so that the silicon powder and ammonium molybdate tetrahydrate are evenly dispersed. Then, the mixed solution was dried to obtain Si / H 24 Mo 7 N 6 o 24 4H 2 O.

[0033] 2) Preparation of SiO x / MoO 2 : Si / H 24 Mo 7 N 6 o 24 4H 2 O powder was placed in a tube furnace. Subsequently, it was annealed at 500° C. for 4 hours in Ar atmosphere, the heating rate was 5° C. / min; the cooling rate w...

Embodiment 2

[0038] Preparation of high-purity and high-crystallinity MoO 2 ,Proceed as follows:

[0039] 1) Preparation of Si / H 24 Mo 7 N 6 o 24 4H 2 O: Weigh 0.5g of silicon powder (submicron, average particle size is 100nm, purity>99.9%, specific surface area is 8.30m 2 / g, the bulk density is 1.89g / cm 3 , the crystal form is spherical) into a beaker filled with 200mL of absolute ethanol, and stirred at room temperature for 12h with a magnet until uniformly dispersed. Then add 1g ammonium molybdate tetrahydrate (H 24 Mo 7 N 6 o 24 4H 2 O), continue to stir with the magnet for 12h, so that the silicon powder and ammonium molybdate tetrahydrate are evenly dispersed. Then, the mixed solution was dried to obtain Si / H 24 Mo 7 N 6 o 24 4H 2 O.

[0040] 2) Preparation of SiO x / MoO 2 : Si / H 24 Mo 7 N 6 o 24 4H 2 O powder was placed in a tube furnace. Subsequently, it was annealed at 400° C. for 48 hours in Ar atmosphere, the heating rate was 1° C. / min; the cooling rat...

Embodiment 3

[0044] Preparation of high-purity and high-crystallinity MoO 2 ,Proceed as follows:

[0045] 1) Preparation of Si / H 24 Mo 7 N 6 o 24 4H 2 O: Weigh 3g silicon powder (submicron, average particle size is 100nm, purity>99.9%, specific surface area is 8.30m 2 / g, the bulk density is 1.89g / cm 3 , the crystal form is spherical) into a beaker filled with 200mL of absolute ethanol, and stirred at room temperature for 12h with a magnet until uniformly dispersed. Then add 1g ammonium molybdate tetrahydrate (H 24 Mo 7 N 6 o 24 4H 2 O), continue to stir with the magnet for 12h, so that the silicon powder and ammonium molybdate tetrahydrate are evenly dispersed. Then, the mixed solution was dried to obtain the Si / H 24 Mo 7 N 6 o 24 4H 2 O.

[0046] 2) Preparation of SiO x / MoO 2 : Si / H 24 Mo 7 N 6 o 24 4H 2 O powder was placed in a tube furnace. Subsequently, it was annealed at 1000° C. for 2 hours in an Ar atmosphere, the heating rate was 15° C. / min; the cooling ...

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Abstract

The invention discloses a high-purity and high-crystallinity MoO 2 method of preparation. Add the silicon powder into absolute ethanol and stir for more than 12 hours until it is uniformly dispersed; then add ammonium molybdate tetrahydrate and continue stirring for more than 12 hours to disperse the silicon powder and ammonium molybdate tetrahydrate evenly; dry the uniformly mixed solution to obtain powder; place the obtained powder in a tube furnace, heat up to 400-1000°C in an Ar atmosphere and anneal for 2-48 hours to obtain the powder; uniformly disperse the obtained powder in NaOH solution, and use deionized water for the precipitate Washed with ethanol and dried in vacuum to obtain MoO 2 . Compared with the hydrothermal method, the present invention has better crystallinity and higher purity. Interfacial redox method is a simple and efficient method for the synthesis of highly crystalline MoO 2 The way.

Description

technical field [0001] The invention belongs to the field of material technology, in particular to a high-purity and high-crystallinity MoO 2 A method for preparing a negative electrode material for a lithium ion battery. Background technique [0002] In recent decades, the electronic information industry has developed vigorously. The widespread use of devices such as electric vehicles, mobile phones, and laptop computers highlights the advantages of lithium-ion batteries (LIBs). LIBs have a promising prospect in theory due to their small size, long service life and good environmental compatibility. However, the specific capacity of the graphite negative electrode currently used in industrialization is only 372 mAhg -1 , hindering the application of LIBs in lightweight, high-power devices, such as electric vehicles. Therefore, improving the specific capacity of LIBs anode materials is a very important development direction. [0003] Molybdenum dioxide (MoO 2 ) has a de...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H01M4/38H01M4/485
CPCH01M4/386H01M4/485Y02E60/10
Inventor 熊传溪郑瑜环胡国华
Owner WUHAN UNIV OF TECH