Silicon-based composite cathode material for lithium-ion battery and preparation method thereof

A technology for lithium-ion batteries and negative electrode materials, applied in battery electrodes, secondary batteries, circuits, etc., to achieve the effects of inhibiting agglomeration, inhibiting volume expansion, and improving first-week Coulombic efficiency and cycle performance

Active Publication Date: 2017-05-31
SHAANXI COAL & CHEM TECH INST
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Problems solved by technology

Utilizing the "zero strain" characteristics of titanium dioxide and the cavity structure to enhance the material's ability to withstand stress, while pyrolytic carbon provides a good conductive network, the negative electrode material not only exhibits a high specific capacity, but also has excellent first-week coulombic efficiency and Cycle stability performance, this method has not yet been reported in literature and patents

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  • Silicon-based composite cathode material for lithium-ion battery and preparation method thereof
  • Silicon-based composite cathode material for lithium-ion battery and preparation method thereof
  • Silicon-based composite cathode material for lithium-ion battery and preparation method thereof

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preparation example Construction

[0037] A method for preparing a silicon-based composite negative electrode material for a lithium-ion battery, comprising the following steps:

[0038] 1) Using the precipitation co-distillation method to coat the organic polymer layer on the surface of the nano-silicon particles to synthesize a composite material with a core-shell structure:

[0039] a) Disperse nano-silicon in the ammonia water-ethanol mixture (V:V, 1:20) according to 1~10g / L, and methacryloyl Oxypropyltrimethoxysilane MPS was slowly added to the mixed liquid, stirred and reacted for 12-24 hours, and modified Si-MPS silicon particles with active double bonds grafted on the surface were obtained;

[0040]b) The modified Si-MPS silicon particles obtained in step a) are based on the modified Si-MPS silicon and methacrylic acid monomer, ethylene glycol dimethacrylate crosslinking agent and azobisisobutyronitrile as the initiator mass The volume ratio is 1:(1~2):(0.5~2):(0.015~0.12) respectively add methacrylic ...

Embodiment 1

[0046] Disperse 0.8 g of silicon spheres with a diameter of about 50 nm into 800 mL of absolute ethanol solution, add 40 mL of 25% ammonia water under stirring conditions, and then slowly add 8 g of methacryloxypropyltrimethoxysilane (MPS) to the above silicon suspension Stir in the turbid solution for 12 hours, wash three times with alcohol and water respectively, and obtain Si-MPS particles with active double bonds grafted on the surface. The resulting 0.8 g Si-MPS particles were ultrasonically dispersed in 107 mL of acetonitrile, 0.8 mL of methacrylic acid (MAA) and 0.4 mL of ethylene glycol dimethacrylate (EGDMA) were added, and 0.012 mL of azobisiso Butyronitrile (AIBN) was used as the initiator, and the composite microspheres Si@PMAA with organic carboxylic acid shells on the surface were obtained by reflux at 90 °C for 1 h. Ultrasonically disperse 0.8g of composite microspheres at 1.0g / L in 800mL of acetonitrile and ethanol (V / V, 1:2) mixture, add 0.4g of cetyltrimethyl...

Embodiment 2

[0050] Disperse 1.6g of silicon spheres with a diameter of about 50nm into 800mL of absolute ethanol solution, add 40mL of 25% ammonia water under stirring conditions, and then slowly add 24g of methacryloxypropyltrimethoxysilane (MPS) to the above silicon in the suspension, stirred for 20 hours, and washed three times with alcohol and water respectively to obtain Si-MPS particles grafted with active double bonds on the surface. The resulting 1.6 g of Si-MPS particles were ultrasonically dispersed in 320 mL of acetonitrile, 2.4 mL of methacrylic acid (MAA) and 2.4 mL of ethylene glycol dimethacrylate (EGDMA) were added, and 0.048 mL of azobisisobutyl Nitrile (AIBN) was used as the initiator, and the composite microspheres Si@PMAA with organic carboxylic acid shells on the surface were obtained by reflux at 95 °C for 1.5 h. 2.0g of composite microspheres were ultrasonically dispersed in 800mL of acetonitrile and ethanol (V / V, 1:3) mixture according to 2.5g / L, and 3.2g of cetylt...

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Abstract

The invention discloses a silicon-based composite cathode material for a lithium-ion battery and a preparation method thereof. The silicon-based composite cathode material for the lithium-ion battery adopts a yolk-shell structure with nanometer silicon as the inner core and with porous titanium dioxide (p-TiO2(at)C), which is coated by pyrolytic carbon inside and outside, as the shell layer. The composite material Si(at)C-void(at)p-TiO2(at)C with the yolk-shell structure is prepared by using a precipitation-codistillation method to coat an organic layer on the surface of the nanometer silicon, using a soft template method to coat a mesoporous TiO2 inorganic layer on the surface of the organic layer in a hydrolyzed manner, coating an organic carbon source on the surface of the mesoporous TiO2 shell layer and carrying out high-temperature carbonization on the organic carbon source under the inert atmosphere. The prepared silicon-based composite cathode material for the lithium-ion battery has the advantages that the high capacity of the silicon material and the high stability of TiO2 are sufficiently utilized, the volume expansion of the nanometer silicon is effectively inhibited through a cavity core-shell structure, a conductive network is constructed within the material by using the pyrolytic carbon, and the first-week coulombic efficiency and cycling stability of the material are enhanced through the synergistic effect of the components; therefore, the silicon-based composite cathode material for the lithium-ion battery is an ideal lithium-ion battery cathode material.

Description

technical field [0001] The invention belongs to the technical field of lithium ion batteries, and in particular relates to a silicon-based composite negative electrode material for lithium ion batteries and a preparation method thereof. Background technique [0002] Lithium-ion batteries have the advantages of high working voltage, large specific energy, stable discharge, small size, and light weight. They have shown broad application prospects in portable electronic equipment, electric vehicles, space technology and other fields. material, the actual specific capacity is close to the theoretical value of 372mAh / g, it is difficult to meet the higher requirements of green energy technology and low-carbon economic development for the next generation of lithium-ion batteries, so the development of high specific capacity negative electrode materials has become a research topic for lithium-ion batteries. an important direction. [0003] Silicon can form alloys with lithium in va...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M4/36H01M4/38H01M4/62H01M10/0525
CPCH01M4/366H01M4/386H01M4/62H01M4/625H01M4/628H01M10/0525Y02E60/10
Inventor 沈晓辉范瑞娟张大鹏曹国林田占元邵乐
Owner SHAANXI COAL & CHEM TECH INST
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