Low-cost and stable lithium battery silicon negative electrode and preparation method thereof

A technology of silicon anode and lithium battery, applied in battery electrodes, secondary batteries, circuits, etc., can solve the problems of increased volume, high cost, complicated process, etc., and achieve the effect of reducing preparation cost, simple method and simplifying preparation process

Inactive Publication Date: 2019-04-23
CHENDU NEW KELI CHEM SCI CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0006] Aiming at the existing problems of complex silicon negative pole expansion process, high cost, and volume increase after porosity, the present invention provides a low-cost method for preparing a stable lithium battery silicon negative pole, by directly dispersing nano-silicon in the deformation memory The silicon negative electrode is prepared in silicone rubber, which greatly simplifies the preparation process, reduces the preparation cost, and better solves the problem of silicon expansion and fragmentation

Method used

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  • Low-cost and stable lithium battery silicon negative electrode and preparation method thereof

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Experimental program
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Effect test

Embodiment 1

[0026] (1) Silicon-based nanoparticles with a particle size of 80nm, a viscosity of less than 5000mpa·s, a tensile strength of 6MPa, and an elongation of 20kN·m -1 Liquid silicone rubber and ethylene-vinyl acetate copolymer with a weight-average molecular weight of 100,000 are mixed evenly at a mass ratio of 10:3:1, heated to 120°C and melted, and the stirring speed is controlled to 700r / min to stir evenly so that silicon-based nanoparticles are evenly dispersed in the melt. body;

[0027] (2) Add 18 parts by weight of MgO, 8 parts by weight of graphene powder, and 45 parts by weight of carbon fiber into the prefabricated melt in step (1), set the ultrasonic dispersion power to 400-600W, and disperse for 20 minutes to obtain a slurry thing;

[0028] (3) Apply the slurry in step (2) to the surface of the negative electrode current collector, cure at 80°C for 2 hours, dry, slitting, and sheet-making to obtain a silicon negative electrode for a lithium battery.

[0029]The nega...

Embodiment 2

[0031] (1) Silicon-based nanoparticles with a particle size of 56nm, a viscosity of less than 5000mpa·s, a tensile strength of 5.8MPa, and an elongation of 24kN·m -1 Liquid silicone rubber and ethylene-vinyl acetate copolymer with a weight-average molecular weight of 60,000 are mixed evenly at a mass ratio of 10:3:1, heated to 110°C and melted, and the stirring speed is controlled to 800r / min to stir evenly so that silicon-based nanoparticles are evenly dispersed in the melt. body;

[0032] (2) Add 13 parts by weight of a mixture of benzoyl peroxide and cumin hydroperoxide (the mass ratio of the two is 1:1), 7 parts by weight of graphene powder, and 45 parts by weight of carbon fiber into step (1) In the prefabricated melt, set the ultrasonic dispersion power to 600W, and disperse for 15 minutes to obtain a slurry;

[0033] (3) Apply the slurry in step (2) to the surface of the negative electrode current collector, cure at 80°C for 2 hours, dry, slitting, and sheet-making to ...

Embodiment 3

[0036] (1) Silicon-based nanoparticles with a particle size of 10nm, a viscosity of less than 5000mpa·s, a tensile strength of 5MPa, and an elongation of 25kN·m -1 Liquid silicone rubber and ethylene-vinyl acetate copolymer with a weight-average molecular weight of 5000 are mixed evenly at a mass ratio of 10:3:1, heated to 105°C and melted, and the stirring speed is controlled to 800r / min to stir evenly so that silicon-based nanoparticles are evenly dispersed in the melt. body;

[0037] (2) Add 24 parts by weight of a mixture of dicyandiamide and organic amide (the mass ratio of the two is 1:1), 10 parts by weight of graphene powder, and 24 parts by weight of carbon fiber into the prefabricated melt of step (1), Set the ultrasonic dispersion power to 400W, and the dispersion time is 25min to obtain a slurry;

[0038] (3) Apply the slurry in step (2) to the surface of the negative electrode current collector, cure at 80°C for 2 hours, dry, slitting, and sheet-making to obtain ...

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Abstract

The invention provides a low-cost and stable lithium battery silicon negative electrode and a preparation method thereof. Silicon-based nanoparticles, liquid silicone rubber and ethylene-vinyl acetatecopolymer are uniformly mixed up according to a mass ratio of 10: 3: 1, and then are heated, melted and dispersed. In this way, silicon-based nanoparticles are uniformly dispersed in the melt. Afterthat, a curing agent, graphene powders and carbon fibers are added into the melt prefabricated in the step (1), and the mixture is ultrasonically dispersed to obtain a slurry. The slurry is coated onthe surface of a negative current collector, and then is cured at 80 DEG C for 2 hours. After that, the material is dried, slit and tabletted to obtain the lithium battery silicon negative electrode.According to the invention, nano silicon is directly dispersed in the deformation memory silicone rubber to prepare the silicon negative electrode. The system has self-repairing performance and shapememory performance at a certain temperature. The problem of silicon expansion fragmentation is well solved. The preparation process is greatly simplified, and the preparation cost is reduced. The defects that an existing technology for solving the problem that a silicon negative electrode is prone to expansion is complex and high in cost, and the size is increased after porosity is achieved are overcome.

Description

technical field [0001] The invention relates to the technical field of lithium batteries, in particular to a low-cost preparation of a stable lithium battery silicon negative electrode and a preparation method thereof. Background technique [0002] Lithium-ion batteries have been widely used in various fields due to their excellent characteristics such as high energy density, high power density, good cycle performance, environmental friendliness, diverse structures, and low price. Lithium-ion battery is a secondary battery that mainly relies on Li + The transfer between the cathode and the anode generates an electric current. When charging, Li + It comes out of the positive electrode and enters the negative electrode through the electrolyte and diaphragm, and the negative electrode is in a lithium-rich state; the opposite is true during discharge, and the positive electrode is in a lithium-rich state. [0003] Anode materials are one of the important components of lithium...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M4/1395H01M4/62H01M4/134H01M10/0525
CPCH01M4/134H01M4/1395H01M4/628H01M10/0525Y02E60/10
Inventor 陈庆曾军堂
Owner CHENDU NEW KELI CHEM SCI CO LTD
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