A double-carbon structure modified silicon-carbon composite negative electrode material and a preparation method thereof

A technology of carbon-silicon composite and negative electrode materials, applied in structural parts, battery electrodes, electrical components, etc., can solve the problems of low conductivity of silicon materials and lithium ion migration rate, poor stability, and inability to meet the application requirements of high power density equipment , to achieve the effect of favorable cycle stability, stable Coulombic efficiency, and increase of effective reaction interface

Active Publication Date: 2019-01-04
WUHAN UNIV OF TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0004] However, silicon materials still face great challenges as anode materials for lithium-ion batteries. On the one hand, silicon materials undergo a large volume change (about 400%) during lithiation and delithiation, and repeated charging and discharging processes will lead to the pulverization of silicon particles. , loss of electrical contact with the current collector and inactivation will also cause the continuous production of the SEI film, causing its capacity to rapidly decay; Low utilization and low capacity retention
Therefore, although silicon materials have high specific capacity, they have poor stability and short cycle life, which cannot meet the application requirements of high power density devices.

Method used

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  • A double-carbon structure modified silicon-carbon composite negative electrode material and a preparation method thereof
  • A double-carbon structure modified silicon-carbon composite negative electrode material and a preparation method thereof
  • A double-carbon structure modified silicon-carbon composite negative electrode material and a preparation method thereof

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Effect test

Embodiment 1

[0037] (1) Disperse 300mg of silicon powder with a size of 100-120nm in an ethanol solution, and ultrasonicate for 2 hours to obtain a suspension; disperse 550mg of citric acid (CA) in an appropriate amount of ethanol solution to obtain a clear solution; add the silicon solution dropwise Enter the citric acid solution, stir at high speed, mix evenly, stir in a water bath at 65°C until all the solvent is evaporated; then raise the temperature to 270°C in a tube furnace under the protection of nitrogen, keep it for 4 hours, cool with the furnace, and grind to obtain Si@C(CA) material;

[0038] (2) Dissolve 150mg of polyacrylonitrile (PAN) in 5ml of dimethylformamide (DMF) solution, stir in an oil bath at 80°C for 2h; add 120mg of Si@C(CA) to the PAN / DMF mixed solution , ultrasonically for 2 hours to make it uniformly dispersed, and then placed on a magnetic stirrer to stir vigorously, and after 15 hours to form a uniformly mixed liquid; slowly add deionized water to the mixed so...

Embodiment 2

[0041] (1) Disperse 200mg of silicon powder with a size of 50-60nm in an ethanol solution, and ultrasonicate for 2 hours; disperse 300mg of citric acid (CA) in an appropriate amount of ethanol solution to obtain a clear solution; drop the silicon powder solution into citric acid In the solution, stir at a high speed, mix evenly, stir in a water bath at 70°C until all the solvent is evaporated; then raise the temperature to 250°C in a tube furnace under the protection of argon, keep it for 4 hours, cool with the furnace, and grind to obtain Si @C(CA)Material;

[0042] (2) Dissolve 150mg of polyacrylonitrile (PAN) in 5ml of dimethylformamide (DMF) solution, stir in an oil bath at 80°C for 2h; add 150mg of Si@C(CA) to the PAN / DMF mixed solution , ultrasonically for 2 hours to make it evenly dispersed, and then placed on a magnetic stirrer to stir vigorously, and a uniformly mixed liquid was formed after 16 hours; deionized water was slowly added dropwise to the mixed solution to ma...

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Abstract

The invention belongs to the field of lithium ion batteries, in particular to a double-carbon structure modified carbon-silicon composite negative electrode material and a preparation method thereof.Double-carbon structure modified carbon-silicon composite cathode material, which has two-stage carbon structure; The nano-silica-carbon clusters with core-shell structure were dispersed uniformly inthe three-dimensional conductive carbon network to form second-order micron-sized particles. The Coulomb efficiency of the battery fabricated by this special structure silicon matrix composite as active material is above 98% after cyclic charging and discharging, and it has good capacity stability. Moreover, the stability and impact resistance are better under different current densities, and themagnification performance is much better than that of simple silicon battery material.

Description

technical field [0001] The invention belongs to the field of lithium-ion batteries, and in particular relates to a silicon-carbon composite material modified with a double-carbon structure for negative electrodes of lithium-ion batteries and a preparation method thereof. Background technique [0002] Electrochemical energy storage is the cleanest technology used in energy storage technology today, and it is also the most promising development direction in the future. Among them, lithium-ion batteries have become high-efficiency energy storage devices for various portable electronic products such as mobile phones and notebook computers due to their advantages such as high energy density, good cycle performance, and no obvious self-discharge phenomenon, and have been applied in electric vehicles. It will even spread to high-end fields such as aerospace and military. [0003] For lithium-ion batteries, the negative electrode material largely determines the energy density of th...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M4/36H01M4/38H01M4/583H01M10/0525
CPCH01M4/366H01M4/386H01M4/583H01M10/0525Y02E60/10
Inventor 王雅东韩雯淼张悦张楠李线线何健威
Owner WUHAN UNIV OF TECH
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