Boron-doped silicon-based negative electrode material used for lithium ion battery

A silicon-based negative electrode material, lithium-ion battery technology, applied in battery electrodes, nanotechnology for materials and surface science, secondary batteries, etc., can solve the problem of not improving the electronic conductivity of silicon materials, and achieve follow-up processing methods Convenience, simple preparation process, natural and easy-to-obtain raw materials

Inactive Publication Date: 2017-09-22
HEFEI GUOXUAN HIGH TECH POWER ENERGY
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

However, these methods all use carbon materials or conductive polymers to improve the electronic conductivit

Method used

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  • Boron-doped silicon-based negative electrode material used for lithium ion battery
  • Boron-doped silicon-based negative electrode material used for lithium ion battery
  • Boron-doped silicon-based negative electrode material used for lithium ion battery

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0029] Add 1g of boron trioxide and 10g of silicon nanowires into a mortar, grind to make the materials evenly dispersed, put the materials into a porcelain boat, put them into a tube furnace with nitrogen, and heat up at a rate of 5°C / min Sinter at 900°C for 1h. Cool to room temperature, immerse the material in sodium hydroxide solution for 0.5 h, wash with deionized water and dry to obtain a silicon-based negative electrode material (boron-doped silicon nanowire).

[0030] The electrochemical performance test of the silicon-based negative electrode material was carried out with a semiconductor characteristic analysis system using two probes, and its conductivity is shown in Table 1 and figure 1 shown. The electronic conductivity of the boron-doped silicon nanowire material after sintering at 900℃ for 1h is 5.2×10 -4 S / cm, so the silicon-based negative electrode material prepared by the present invention has improved electronic conductivity after being doped with boron.

Embodiment 2

[0034] Add 1g of boron trioxide and 10g of silicon nanowires into the mortar, grind the material to disperse evenly, put the material into a porcelain boat, put it into a tube furnace with nitrogen gas, and raise the temperature to 5°C / min. Sinter at 1000°C for 1h. Cool to room temperature, immerse the material in sodium hydroxide solution for 0.5 h, wash with deionized water and dry to obtain a silicon-based negative electrode material (boron-doped silicon nanowire).

[0035] The semiconductor characteristic analysis system uses two probes to test the electrochemical performance of the material, and its conductivity is shown in Table 1 and figure 1 shown. The electronic conductivity of boron-doped silicon nanowire material after sintering at 1000℃ for 1h is 0.21S / cm. By comparison, it can be found that the electronic conductivity of the material after boron doping is improved, and to a certain extent increases with the increase of temperature.

[0036] Table 1 Electronic c...

Embodiment 3

[0039] Add 1g of diboron trioxide and 10g of nano-silicon particles into the mortar, grind the material to disperse evenly, put the material into a porcelain boat, put it into a tube furnace with nitrogen, and raise the temperature to 1000 at a heating rate of 20°C / min. Sintering at ℃ for 1h. Cool to room temperature, soak the material in sodium hydroxide solution for 0.5 h, wash with deionized water and dry to obtain a silicon-based negative electrode material (boron-doped nano-silicon).

[0040] figure 2 According to the EDS energy spectrum, it can be found that there is obvious boron element in the material.

[0041] Nano-silicon: SP: LA133 = 8:1:1 ratio was mixed and coated, and CR2016 button cells were assembled. The electrolyte was EC+DMC solution with 1mol / L LiPF6, and the electrochemical performance was tested.

[0042] Such as image 3 Shown are the charge-discharge curves of nano-silicon and boron-doped nano-silicon, from image 3 It can be seen that the first cha...

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Abstract

The invention discloses a boron-doped silicon-based negative electrode material used for a lithium ion battery. The boron-doped silicon-based negative electrode material is prepared from a boron-doped nanometer silicon material and graphite in a compounding manner, wherein the mass percentage of the boron-doped nanometer silicon material is 3-100%, and the balance is graphite. Diboron trioxide is gradually diffused to the silicon negative electrode material in a high-temperature sintering process to replace a part of silicon atoms to form displacement type doping, so that vacancy carrier concentration in the nanometer silicon material is improved, thereby improving the intrinsic electron conductivity of the silicon material; volume expansion of the silicon material can be buffered by graphite; and the boron-doped silicon-based negative electrode material has simple preparation process, convenience in operation, natural and easily available raw materials, low cost, convenience in subsequent processing mode, and easy realization of large-scale production.

Description

technical field [0001] The invention relates to the technical field of lithium ion batteries, in particular to a boron-doped silicon-based negative electrode material for lithium ion batteries. Background technique [0002] In recent years, with the continuous expansion of the application of lithium-ion batteries in high-power equipment such as electric tools, electric / hybrid vehicles, and energy storage power stations, traditional graphite negative electrodes (372mAh / g) have been difficult to meet human needs for high-energy-density batteries. Therefore, finding a next-generation lithium-ion battery anode material that can replace graphite has become one of the current research hotspots in lithium-ion batteries. The theoretical specific capacity of silicon material is 4200mAh / g, which is rich in resources, and will not co-intercalate with the electrolyte, and has a higher potential for lithium intercalation, which is safer. However, the silicon electrode material will expe...

Claims

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Application Information

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IPC IPC(8): H01M4/36H01M4/38H01M4/62H01M10/0525B82Y30/00
CPCB82Y30/00H01M4/362H01M4/386H01M4/625H01M10/0525Y02E60/10
Inventor 王辉郭桂略朱丽丽
Owner HEFEI GUOXUAN HIGH TECH POWER ENERGY
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