Method for preparing silicon-based anode material of lithium-ion battery

A technology for lithium-ion batteries and composite materials, applied in the field of preparation of silicon-based negative electrode composite materials for lithium-ion batteries, can solve problems affecting electrode cycle stability, achieve good electrochemical performance, low raw material cost, and simple process

Inactive Publication Date: 2009-09-16
UNIV OF SCI & TECH BEIJING
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, the negative electrode composed of pure Si powder will be accompanied by a large volume change during the lithium-deintercalation process, which will affect the cycle stability of the electrode.

Method used

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  • Method for preparing silicon-based anode material of lithium-ion battery
  • Method for preparing silicon-based anode material of lithium-ion battery
  • Method for preparing silicon-based anode material of lithium-ion battery

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0017] SiO 2 (≥98.5%) and Mg (>99.0%) are the initial raw materials, and the molar ratio is 1:2. 700°C, keep warm for 2 hours, then turn off the power, and cool down to room temperature naturally. The XRD phase analysis result ( figure 1 shown) shows that the synthesized products are Si, MgO and a small amount of Mg 2 Si and MgSiO 3 , Mg 2 SiO 4 , without the presence of other oxide impurity phases.

[0018] Mix the synthetic product, the conductive agent acetylene black, and the binder PVDF at a mass ratio of 75:15:15, add an appropriate amount of NMP to make a slurry, apply it evenly on the copper foil, and cut it into a circular pole piece after drying. The experimental battery composed of metal lithium was subjected to constant current charge and discharge experiments. The charge and discharge current was 100mA / g, and the charge and discharge voltage range was controlled between 0.01-1.5V. The first discharge specific capacity of the prepared Si / MgO composite negati...

Embodiment 2

[0020] SiO 2 (≥98.5%) and Mg (>99.0%) are the initial raw materials, and the molar ratio is 1:2 for batching, the mixture is put into a ball milling tank, the mass ratio of balls to the mixture is 20:1, and high-energy ball milling is carried out under an inert atmosphere 2 hours at 500 rpm. The XRD phase analysis result ( figure 2 Shown) shows that the synthesized products are mainly Si, MgO.

[0021] Mix the synthetic product, the conductive agent acetylene black, and the binder PVDF at a mass ratio of 75:15:15, add an appropriate amount of NMP to make a slurry, apply it evenly on the copper foil, and cut it into a circular pole piece after drying. The experimental battery composed of metal lithium was subjected to constant current charge and discharge experiments. The charge and discharge current was 100mA / g, and the charge and discharge voltage range was controlled between 0.01-1.5V. The first discharge specific capacity of the prepared Si / MgO composite negative electr...

Embodiment 3

[0023] SiO 2 (≥98.5%) and Mg (>99.0%) are the initial raw materials, and the molar ratio is 1:2. 650°C, keep warm for 4 hours, then turn off the power, and cool down to room temperature naturally.

[0024] Mix the synthetic product, the conductive agent acetylene black, and the binder PVDF at a mass ratio of 75:15:15, add an appropriate amount of NMP to make a slurry, apply it evenly on the copper foil, and cut it into a circular pole piece after drying. The experimental battery composed of metal lithium was subjected to constant current charge and discharge experiments. The charge and discharge current was 100mA / g, and the charge and discharge voltage range was controlled between 0.01-1.5V. The first discharge specific capacity of the prepared Si / MgO composite negative electrode material is about 1290mAh / g, and the first charge specific capacity is 980mAh / g.

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Abstract

The invention relates to a method for preparing a silicon-based anode material of a lithium-ion battery, belonging to the field of lithium-ion battery. Silicon oxide and Mg powder are weighed and matched, the adding amount of the magnesium powder and the silicon oxide is calculated according to the Mg / O atomic ratio of 0.1:1-1.3:1, the magnesium powder and the silicon oxide are evenly mixed and placed in flowing nitrogen or argon and other inert atmospheres, the needed temperature of 500-1000 DEG C is achieved by the temperature increase rate of 1-30 DEG C / min, and the temperature is kept for 0.5-6 hours. Then, the mixture is cooled to room temperature by program in a temperature-controlling manner or by power-off in a natural manner. Or the silicon oxide, the Mg and balls are weighed and matched, the mixture is arranged in a ball mill, the high energy ball milling is carried out under the inert atmosphere, the ratio of the balls to materials is 1:1-50:1, the rotational speed is 100-3000 turns, and the ball milling time is 0.5-100 hours. The method has the advantages of low material cost, simple process, less time consumption, high yield and good capacity and circulating performance of products.

Description

technical field [0001] The invention belongs to the technical field of lithium ion batteries, and provides a preparation method for silicon-based negative electrode composite materials of lithium ion batteries. Background technique [0002] Mobile communications, laptop computers and digital cameras are the three fastest-growing industries in the global electronic information industry. With the rapid development of these industries, lithium-ion batteries, one of the most important accessories of these three leading products, are undoubtedly It has also become a very promising sunrise industry. Compared with traditional Ni / Cd and Ni / MH batteries, lithium-ion batteries have the advantages of high energy density, high working voltage, good load characteristics, fast charging speed, safety and pollution-free, and are currently the fastest growing and brightest market prospect A secondary battery. [0003] Lithium transition metal oxide / graphite system is mostly used in commerc...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M4/04H01M4/38H01M4/62
CPCY02E60/12Y02E60/10
Inventor 赵海雷陈敬波王静何见超王梦微
Owner UNIV OF SCI & TECH BEIJING
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