A kind of nano-silicon material and its application

A nano-silicon and nano-technology, which is applied in the application of negative electrode materials for lithium ion batteries, in the field of nano-silicon materials, can solve the problems of difficulty in synthesis, difficulty in meeting large-scale production, increase in synthesis cost, etc., and achieves low cost, easy amplification and synthesis, high yield effect

Active Publication Date: 2017-10-20
NANJING UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

However, the existing reports need to synthesize and provide a certain amount of nano-SiO 2 Precursor, which not only increases the synthesis cost, but also SiO with particle size less than 100nm 2 The synthesis of is also very difficult, so the existing magnesia thermal reduction of SiO 2 method is difficult to meet the needs of large-scale production

Method used

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  • A kind of nano-silicon material and its application
  • A kind of nano-silicon material and its application
  • A kind of nano-silicon material and its application

Examples

Experimental program
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Effect test

Embodiment 1

[0044]Step 1: Pass the untreated attapulgite through a 200-mesh molecular sieve, add 10 g to 300 mL of 2M HCl solution, and react at 70° C. for 30 h. Filtrate, wash with water until neutral, dry in an oven at 80°C, and heat-treat in a muffle furnace at 600°C for 4 hours to obtain nano-SiO with a rod-like structure 2 . Its scanning electron microscope pictures are as figure 1 As shown, the length is 300-800 nm and the width is 20-40 nm.

[0045] The second step: the Mg and SiO 2 The powder is ground evenly with a molar ratio of 2:1 (2g SiO 2 ), placed in a porcelain boat, reacted in a tube furnace at 680°C for 4h under an Ar atmosphere, and the product was stirred and reacted at room temperature for 5h and 10min respectively in 1M HCl and 6% HF to obtain a uniform particle size distribution less than 100nm Elemental silicon material (0.8g), its scanning electron microscope photo is as follows figure 2 shown. From its transmission electron microscope pictures (such as i...

Embodiment 2

[0050] The first step, the third step and the fourth step are shown in Example 1, and the second step is the second step Mg powder and SiO in Example 1 2 The molar ratio of 3:1 (2g SiO 2 ), where the magnesium powder is placed on the lower layer of the porcelain boat, SiO 2 Uniformly coated on the upper porous stainless steel mesh, reacted at 850°C for 5h. The charge-discharge performance and discharge capacity of the battery obtained are the same as those in Example 1.

Embodiment 3

[0052] See Example 1 for the first, second and fourth steps. In the third step, the source of C to coat Si comes from glucose, and the obtained elemental silicon material is ultrasonically dispersed in an ethanol solution dissolved with a certain amount of glucose, at 200°C Hydrothermal treatment for 5h. The filtered, washed and dried samples were heat-treated in a tube furnace at 700 °C for 3 h under an Ar atmosphere. The charge-discharge performance and discharge capacity of the battery obtained are the same as those in Example 1.

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Abstract

The invention discloses a nano-silicon material which is prepared by the following steps: using a rod-shaped nano SiO2 material with the length of 300-800nm and the width of 20-40nm, and preparing the nano-silicon material by virtue of a magnesiothermic reduction method, wherein the rod-shaped nano SiO2 material is prepared by the steps of taking attapulgite as a raw material, screening, pickling and performing high-temperature heat treatment. According to the nano-silicon material disclosed by the invention, cheap and natural attapulgite serves as a precursor, the rod-shaped nano SiO2 is purified from the attapulgite, an elemental silicon material with uniform particle size distribution is prepared in one step, amplified synthesis is easily realized in the method, gram-grade reaction can be achieved in a lab, and the cost is low; and moreover, the obtained elemental silicon material is high in yield, the elemental silicon material subjected to carbon coating treatment serves as a negative electrode material of a lithium ion battery, and excellent lithium storage performance is achieved.

Description

technical field [0001] The invention belongs to the field of nano-materials, and specifically relates to a nano-silicon material and its application, that is, extracting and synthesizing the nano-silicon material from natural attapulgite, and its application as a lithium-ion battery negative electrode material. Background technique [0002] Compared with the traditional graphite negative electrode lithium battery, the lithium ion battery of silicon negative electrode material has a series of advantages such as large specific capacity (~4000mAh / g), low discharge platform and abundant sources. Silicon replaces traditional graphite as the negative electrode of lithium ion battery Promising material. [0003] Although silicon materials have attractive prospects as lithium battery anodes, their disadvantages are also obvious, the most important being the formation of Li x Si alloys cause the volume of silicon to expand by nearly 400%, and such a large volume effect can cause the...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H01M4/38B82Y30/00
CPCB82Y30/00H01M4/386H01M4/48H01M4/625H01M10/0525Y02E60/10
Inventor 杜红宾孙林
Owner NANJING UNIV
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