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A preparation method of silica composite gel and a three-dimensional porous silicon negative electrode material prepared using the gel

A composite gel and silica technology, applied in battery electrodes, structural parts, electrical components, etc., can solve the problems of poor electrochemical reversibility, poor cycle stability, and low reversible capacity, and achieve easy scale production and slow down brittleness. The effect of cracking powder and simple preparation process

Active Publication Date: 2020-06-12
郑州中科新兴产业技术研究院
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

However, it introduces hydrofluoric acid when preparing porous silicon, which will cause serious harm to the environment
Chinese patent CN 106602022 A discloses a porous silicon / titanium dioxide composite negative electrode material prepared from diatomite. The composite material has regular pores and can provide a certain space for the volume expansion of silicon, but the material has a reversible capacity for the first time. Low, and poor cycle stability, poor electrochemical reversibility

Method used

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  • A preparation method of silica composite gel and a three-dimensional porous silicon negative electrode material prepared using the gel
  • A preparation method of silica composite gel and a three-dimensional porous silicon negative electrode material prepared using the gel

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Experimental program
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Embodiment 1

[0037] (1) Preparation of silica composite gel

[0038] (1) Weigh 3.603 g (0.2 mol) of water, 0.2304 g (0.005 mol) of urea, 0.1208 g (0.0005 mol) of copper nitrate trihydrate, add 24 g of ethanol, and ultrasonically obtain a uniform transparent blue solution, and then add 2.0833 g (0.010mol) tetraethyl orthosilicate was added to the above solution, and mixed to obtain a precursor solution;

[0039] (2) Transfer the obtained precursor solution to a reaction kettle with a polytetrafluoroethylene substrate, and react at 120 °C for 12 hours to obtain a blue silica-copper ion composite gel.

[0040] (2) Preparation of three-dimensional porous silicon anode materials

[0041] 1) Put the silica-copper ion composite gel prepared in (1) into a beaker, and add water to perform solvent replacement. Add 2.0 g of inorganic salt sodium chloride to the gel, stir vigorously to mix evenly, and freeze-dry (4.0 °C, 5 h) to obtain a uniformly mixed freeze-dried product;

[0042] 2) Mix 1.0 g f...

Embodiment 2

[0048] (1) Preparation of silica composite gel

[0049] (1) Weigh 3.603 g (0.2 mol) of water, 0.2304 g (0.005 mol) of urea, 0.1332 g (0.0005 mol) of chromium chloride hexahydrate, add 24 g of ethylene glycol, and ultrasonically obtain a uniform transparent green solution. 2. Add 0833 g (0.010 mol) tetraethyl orthosilicate to the above solution and mix to obtain a precursor solution;

[0050] (2) Transfer the obtained precursor solution to a polytetrafluoroethylene substrate reaction kettle, and react at 150 °C for 4 hours to obtain a green silica-chromium ion composite gel.

[0051] (2) Preparation of three-dimensional porous silicon anode materials

[0052] 1) Put the silica-chromium ion composite gel prepared in (1) into a beaker, and add water for solvent replacement, and then remove the inert solvent ethylene glycol to 1.0 g of silica-chromium ion Add 3.0 g of inorganic salt potassium chloride to the composite gel, stir vigorously and mix uniformly, and freeze-dry to obt...

Embodiment 3

[0055] (1) Preparation of silica composite gel

[0056] (1) Weigh 3.603 g (0.2 mol) of water, 0.2304 g (0.005 mol) of urea, 0.2027 g (0.00075 mol) of ferric chloride hexahydrate, add 24 g of methanol, and ultrasonically obtain a uniform transparent light yellow solution, and then add 2.0833 g (0.010mol) tetraethyl orthosilicate was added to the above solution, and mixed to obtain a precursor solution;

[0057] (2) The obtained precursor solution was transferred to a polytetrafluoroethylene-substrated reactor, and reacted for 6 hours at 140 °C to obtain a pale yellow silica-iron ion composite gel.

[0058] (2) Preparation of three-dimensional porous silicon anode materials

[0059] 1) Put the silica-iron ion composite gel prepared in (1) in a beaker, and add water to perform solvent replacement, and then remove the inert solvent methanol to 0.8 g of the silica-iron ion composite gel Add 4.0 g of inorganic salt magnesium chloride, stir vigorously and mix uniformly, and freeze-...

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Abstract

The invention discloses a preparation method of silicon dioxide plural gel and a three-dimensional porous silicon anode material utilizing the same. The preparation method of silicon dioxide plural gel includes (1) mixing a silicon source, a hydrolytic accelerating agent and divalent metal salt solution to prepare precursor solution; (2), subjecting the precursor solution to solvothermal reactionat a certain temperature for a certain time to obtain silicon dioxide plural gel with different compositions and structures. Preparation of the three-dimensional porous silicon anode material includes(1), mixing silicon dioxide plural gel with a reducing agent, namely magnesium powder and a heat absorbent, namely inorganic salt, and performing magnesium thermal reduction reaction in inert atmosphere to obtain magnesium thermal reaction products containing impurity such as magnesium oxide; (2), washing with acid solution to obtain the porous silicon material with regular shape. The preparationmethod is simple without generation of waste liquid of hydrofluoric acid and is easy to realize scale production; the porous material has good cycling stability and rate capability, and has good application prospect.

Description

technical field [0001] The invention relates to the field of negative electrode materials for lithium ion batteries, in particular to a method for obtaining porous silicon negative electrode materials by preparing silica composite gel. Background technique [0002] Lithium-ion batteries have been widely used in 3C fields such as mobile phones, digital cameras, and notebook computers, as well as new energy fields such as electric vehicles and electric buses. However, with the maturity of technology and social development, higher requirements have been put forward for lithium-ion batteries. According to "Made in China 2025", by 2020, the energy density of batteries in my country will reach 300 Wh / kg. To achieve this goal, a lot of research has been carried out in both industry and academia. Silicon-based anode materials are considered to be the most promising next-generation anode materials for lithium-ion batteries that have already begun commercial application. However, i...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H01M4/36H01M4/38
CPCH01M4/362H01M4/386Y02E60/10
Inventor 刘艳侠秦利娟刘凡阮晶晶张锁江刘福园张若涛范亚蒙
Owner 郑州中科新兴产业技术研究院