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Negative active material and preparation method and application thereof

A negative electrode active material and carbon-based material technology, applied in the field of electrochemistry, can solve the problems of limiting the capacity and power performance of lithium-ion batteries, low volume specific capacity, and low tap density, and achieve battery capacity that is not easily attenuated and has high battery capacity , long service life effect

Inactive Publication Date: 2015-11-11
TSINGHUA UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, the above-mentioned negative electrode materials generally have the disadvantages of low tap density and low volume specific capacity, which limits the capacity and power performance of lithium-ion batteries per unit chip area. In addition, they are also difficult to be compatible with microelectronics manufacturing processes.

Method used

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  • Negative active material and preparation method and application thereof
  • Negative active material and preparation method and application thereof
  • Negative active material and preparation method and application thereof

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0056] The process of preparing negative electrode active materials by template method, such as figure 2 As mentioned, the specific method is as follows:

[0057] (a) Ultrasonically disperse 1.5g of silicon particles with an average particle size of 30-50nm in a system of 200mL of ethanol and 50mL of water, then add 10mL of 28%-30% ammonia water, and add 13.5g of tetraethyl orthosilicate (TEOS) dropwise , continuously stirred for 12 hours, hydrolyzed and oxidized on the surface of silicon particles to generate SiO 2 Layer, centrifuged and washed repeatedly to obtain composite particles;

[0058] (b) Mix the above-mentioned composite particles with 13.5g SU-8 photoresist evenly, and spin-coat on the silicon wafer;

[0059] (c) at 900°C, N 2 Carry out high-temperature carbonization of the material in the environment, and the SU-8 photoresist becomes a self-supporting porous carbon skeleton;

[0060] (d) The obtained material is immersed in 4wt% HF, 46wt% water, 50wt% ethano...

Embodiment 2

[0066] Utilize the negative electrode active material prepared in embodiment 1 to prepare button type half battery, concrete processing method is as follows:

[0067] (1) Get the negative electrode active material of silicon content 35% that the embodiment 1 of 4g prepares as active material, 0.5gSuperP is as conductive agent, 0.5g carboxymethyl cellulose (CMC) is as binding agent, is coated on after being dispersed uniformly placed on a copper foil and dried overnight in a vacuum oven at 80°C.

[0068] (2) the product that step (1) obtains at 100kg / cm 2 Down punched into pieces.

[0069] (3) The products stamped into sheets in step (2) are assembled in the glove box as image 3 The shown CR2025 button battery 1, wherein the above-mentioned material is used as the negative electrode, the lithium disc is used as the positive electrode, and the Celgard film is used as the diaphragm, 1mol / LLiPF 6 Mix solution with EC:DEC:DMC (volume ratio 1:1:1) as electrolyte.

[0070] Accor...

Embodiment 3

[0072] The CR2025 button battery obtained in Example 2 was electrochemically tested on a lithium battery charging and discharging system.

[0073] 1. Charge and discharge experiment

[0074] The button battery 1 with a silicon content of 35% obtained in Example 2 is subjected to a charge and discharge test, as follows:

[0075] (1) Test method

[0076] At room temperature, the button battery 1 was tested on a battery testing system (Newwell, CT-3008W).

[0077] Before the test, the battery needs to be aged for 24 hours to allow the electrolyte to fully infiltrate the electrode material.

[0078] The charge cut-off voltage is set to 1.2V, and the discharge cut-off voltage is set to 0.01V.

[0079] The first three cycles are charged and discharged with a small 0.1C rate (current 0.2mA), and the current is increased by 3 times in the subsequent cycle, and the charge and discharge are performed at a rate of 0.3C, that is, a current of 0.6mA. A total of 30 charge and discharge c...

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Abstract

The invention discloses a negative active material and a preparation method and application thereof. The negative active material comprises silica nanoparticles and a carbon-based material layer, wherein the carbon-based material layer is formed on at least part of outer surfaces of the silica nanoparticles, and gaps exist between at least one part of the carbon-based material layer and the outer surfaces of the silica nanoparticles. A battery prepared from the negative active material is high in capacity, good in circularity and long in service life, and is difficult to attenuate.

Description

technical field [0001] The present invention relates to the field of electrochemistry, in particular, to a negative electrode active material and its preparation method and application, more specifically, to a negative electrode active material, a method for preparing the negative electrode active material, a negative electrode and a battery. Background technique [0002] Due to the advantages of high open circuit voltage, high energy density, low self-discharge rate and no pollution, lithium-ion batteries are widely used in electronic equipment, electric transportation, aerospace, military, medical and other fields. The charging and discharging process of lithium-ion batteries is based on the repeated intercalation and deintercalation of lithium ions between the positive and negative electrode materials. At present, commercial lithium-ion batteries mainly use carbon materials as negative electrodes, and graphite is the most widely used due to its layered structure that faci...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M4/36H01M4/139H01M10/058
CPCH01M4/139H01M4/36H01M4/364H01M10/058Y02E60/10Y02P70/50
Inventor 王晓红李晓钊
Owner TSINGHUA UNIV
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