Silicon-carbon material serving as lithium ion battery anode and preparation method thereof

A technology of lithium-ion batteries and silicon-carbon materials, applied in battery electrodes, nanotechnology for materials and surface science, secondary batteries, etc., can solve the problems of accelerated capacity decay, attenuation, and inability to produce surface solid electrolyte membranes, etc. To achieve the effect of buffering volume expansion and enriching the pore structure

Inactive Publication Date: 2018-09-28
SOUTH CHINA UNIV OF TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, during the process of intercalating and deintercalating lithium, the Si material will expand by about 300% in volume, resulting in electrode powderization and rapid capacity decay, which affects the safety and cycle performance of lithium-ion batteries.
At the same time, due to the volume expansion effect of the Si material, it cannot produce a solid surface solid electrolyte film in the electrolyte, resulting in the destruction of the electrode structure, and the new solid electrolyte interfacial film (SEI) will continue to form on the newly exposed silicon surface. formation, resulting in reduced charge and discharge efficiency and accelerated capacity fading

Method used

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  • Silicon-carbon material serving as lithium ion battery anode and preparation method thereof
  • Silicon-carbon material serving as lithium ion battery anode and preparation method thereof

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Effect test

Embodiment 1

[0023] A method for preparing a new-structured silicon-carbon material for the negative electrode of a lithium ion battery, the specific steps are as follows:

[0024] (1) Preparation of porous silicon:

[0025] Polycrystalline silicon powder cleaning: Soak 350 mesh 5g silicon powder with a 9% HCl solution for 25 minutes to remove impurities; filter with a 100 mesh porous filter membrane and clean it with deionized water for later use;

[0026] Deposition of nano-Ag particles: Put the cleaned polysilicon powder into a mixed solution of 0.01mol / L AgNO3 and 1% HF, deposit Ag for 1 min, and coat the surface of silicon with nano-particle Ag; use 100 Purpose the porous filter membrane is filtered and cleaned with deionized water for use;

[0027] The appearance of porous silicon: the silicon powder deposited with Ag particles is placed in 5% HF and 1% H 2 O 2 In the mixed etching solution, at 20℃, react for 2h, Ag is used as a catalyst to accelerate the reaction of silicon around Ag partic...

Embodiment 2

[0034] A method for preparing a new-structured silicon-carbon material for the negative electrode of a lithium ion battery, the specific steps are as follows:

[0035] (1) Preparation of porous silicon:

[0036] Polycrystalline silicon powder cleaning: soak 8g of 400 mesh silicon powder for 30 minutes with a mass fraction of 10% HCl solution, the purpose is to remove impurities; filter with a 200 mesh porous membrane, and clean it with deionized water for later use;

[0037] Deposition of nano-Ag particles: Put the cleaned polysilicon powder into a mixed solution of 0.02mol / L AgNO3 and 2% HF, deposit Ag for 2min, and coat the surface of silicon with nano-particle Ag; use 200 Purpose the porous filter membrane is filtered and cleaned with deionized water for use;

[0038] The appearance of porous silicon: the silicon powder deposited with Ag particles is placed in 8% HF and 1% H 2 O 2 In the mixed etching solution, at 20℃, react for 2h. Ag is used as a catalyst to accelerate the reacti...

Embodiment 3

[0045] A method for preparing a new-structured silicon-carbon material for the negative electrode of a lithium ion battery, the specific steps are as follows:

[0046] (1) Preparation of porous silicon:

[0047] Polycrystalline silicon powder cleaning: Soak 10g silicon powder of 450 mesh with a mass fraction of 11% HCl solution for 35 minutes, the purpose is to remove impurities; filter with a 300 mesh porous filter membrane, and rinse with deionized water for use;

[0048] Deposit nano Ag particles: Put the cleaned polysilicon powder into 0.03mol / L AgNO 3 In the mixed solution of 3% HF and 3% HF, deposit Ag for 3 minutes, and plate the surface of the silicon with nano-particle Ag; filter with a 300 mesh porous filter membrane, and clean it with deionized water for use;

[0049] The appearance of porous silicon: the silicon powder deposited with Ag particles is placed in HF with a mass fraction of 10% and a mass fraction of 1.5% H 2 O 2 In the mixed etching solution, at 30℃, react for ...

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Abstract

The invention discloses a silicon-carbon material serving as a lithium ion battery anode and a preparation method thereof. The silicon-carbon material is of a structure that carbon coats porous silicon. The preparation method of the silicon-carbon material serving as the lithium ion battery anode comprises the following concrete steps: (1) preparing porous silicon; (2) preparing a carbonization precursor; and (3) obtaining an anode electrode material. The silicon-carbon material disclosed by the invention can effectively alleviate great volume change in a porous silicon electrode reaction process, and an electrode can be beneficially and fully wetted by electrolyte, so that energy storage efficiency is improved; and diffusion distance of lithium ions also can be shortened, and electron conduction in the porous silicon electrode is promoted, so that charge-discharge efficiency is improved. Meanwhile, a micro-sized carbon fiber and a nanoscale porous silicon lithium ion battery anode material which are manufactured by adopting the silicon-carbon material are large in specific surface area and length-diameter ratio and also have the advantages of small pore diameter, high porosity andhigh fiber uniformity, and the used raw materials are fewer and steps are simple, thereby being beneficial to industrial mass production.

Description

Technical field [0001] The invention relates to the technical field of lithium ion batteries, in particular to a silicon carbon material used for the negative electrode of a lithium ion battery and a preparation method thereof. Background technique [0002] Lithium-ion batteries are widely used as a new type of green secondary battery. Compared with other secondary batteries, they have higher energy density and environmentally friendly characteristics, and have high voltage, high energy density, good cycle performance, low self-discharge, Outstanding advantages such as no memory effect have been widely used in portable electronic equipment, transportation, defense industry and other fields. At present, in the commercial application of lithium-ion batteries, graphite-like carbon is generally used as a negative electrode material. However, the theoretical capacity of graphite is only 372 mAh / g, and the rate performance is not good, so the development of new high-capacity anode mat...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M4/36H01M4/38H01M4/62H01M10/0525B82Y30/00
CPCB82Y30/00H01M4/366H01M4/386H01M4/625H01M10/0525Y02E60/10
Inventor 袁伟王芷咏潘保有朱璟琦邱志强黄诗敏罗健汤勇
Owner SOUTH CHINA UNIV OF TECH
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