Preparation method of lithium iron phosphate material anode sheet

A technology of lithium iron phosphate and positive electrode sheet, applied in the field of lithium ion battery preparation, can solve the problems of complex preparation process, unsuitable for large-scale preparation and high cost

Active Publication Date: 2013-03-06
内蒙古三信科技发展有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0004] Chinese patent 200610157460.0 improves the coating effect by treating the current collector aluminum foil with an alkaline solution; patent 200810031763.7 modifies the coating performance by treating the lithium iron phosphate material with an alkaline solution and adding a small amount of alkaline substances to the slurry; 200910213426.4 It is to bake all the materials for the conventional preparation of lithium iron phosphate slurry in an inert atmosphere and then add solvent to make pole pieces; patent 200910311361.7 uses modified gum arabic as a binder; 201010207504.2 uses chemical corrosion collectors and additive The method of organic conductive polymers; 201110253249.X uses lithium iron phosphate materials with different particle sizes to prepare slurries and coats them in stages to form two-layer pole pieces; 201110403724.7 adopts a novel idea of ​​preparing integrated electrodes in situ with three-dimensional foam structure metals; These methods have improved the coating performance of lithium iron phosphate to a certain extent, but some methods may not be suitable for large-scale preparation, some preparation processes are complicated, and some have high costs

Method used

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  • Preparation method of lithium iron phosphate material anode sheet
  • Preparation method of lithium iron phosphate material anode sheet
  • Preparation method of lithium iron phosphate material anode sheet

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Experimental program
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Effect test

Embodiment 1

[0021] The steps of preparing ultrafine and nanoscale lithium iron phosphate material positive electrode sheet are as follows:

[0022] (1) According to the mass ratio LiFePO4: acetylene black: conductive graphite: PVDF = 90: 2.5: 2.5: 5, accurately weigh 90g of LiFePO4 positive electrode material with an average particle size of about 2-3μm, 2.5g of acetylene black, and 2.5g of conductive graphite and 5g PVDF; 5g PVDF was prepared into 45ml 10% solution with NMP for use.

[0023] (2) First, mix 2.5g of acetylene black and 2.5g of conductive graphite in a dry glass vessel and place them in a 250ml sealed three-necked bottle with stirring, stirring at a speed of 80 rpm, gradually Add 20ml of NMP, continue to stir and disperse for 20 minutes, then add 90g of lithium iron phosphate material in batches, stir for 30 minutes, gradually add 10% PVDF solution, then add 35ml of NMP to make the solid content about 50%, and stop stirring for 30 minutes.

[0024] (3) scrape-coat the slur...

Embodiment 2

[0029] The steps of preparing ultrafine and nanoscale lithium iron phosphate material positive electrode sheet are as follows:

[0030] (1) According to the mass ratio LiFePO4: carbon nanotubes: conductive graphite: PVDF=90:0.2:4.8:5, accurately weigh 90g of LiFePO4 cathode material with a particle size of about 2-3μm, 0.2g of carbon nanotubes, and 4.8g of conductive graphite Graphite and 5g PVDF; 5g PVDF was prepared into 45ml of 10% solution with NMP for use; 0.5g of sorbitan fatty acid ester (SPAN80) was prepared into solution with 5ml of NMP in advance for use.

[0031] (2) First mix the weighed 0.2g carbon nanotubes and 4.8g conductive graphite in a dry glass vessel and place them in a 250ml sealed three-neck flask with stirring, add 25ml NMP solvent, and start the process at 80 rpm After stirring for 20 minutes, add (1) 5ml of SPAN80 NMP solution, continue to stir for 20 minutes, then add 10ml of NMP, stir and disperse for 30 minutes, gradually add 90g of lithium iron ph...

Embodiment 3

[0037] The steps of preparing ultrafine and nanoscale lithium iron phosphate material positive electrode sheet are as follows:

[0038] (1) According to the mass ratio LiFePO4: acetylene black: conductive graphite: PVDF = 90: 1.5: 3.5: 5, accurately weigh 90g of LiFePO4 positive electrode material with a particle size of about 100nm to 200nm, 1.5g of acetylene black, 3.5g of conductive graphite and 5 g of PVDF; 5 g of PVDF was prepared into 45 ml of a 10% solution with NMP for use; 0.1 g of polyacrylonitrile was pre-prepared into a solution with 10 ml of dimethylformamide for use.

[0039] (2) First, mix 1.5g of acetylene black and 3.5g of conductive graphite in a dry glass vessel and place them in a 250ml sealed three-necked flask with stirring, add 10ml of NMP solvent, and use 80 rpm Stir at high speed, stir for 20 minutes, add 10ml polyacrylonitrile dimethylformamide solution, continue stirring for 20 minutes, then add 10ml NMP, stir and disperse for 30 minutes, gradually a...

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Abstract

The invention relates to a coating method of a lithium iron phosphate material anode sheet, belonging to the technical field of preparation of a lithium ion battery. The invention aims to provide a preparation method of a superfine and nano lithium iron phosphate material anode sheet to improve an anode coating performance, improve a battery discharging performance and prolong the cycle life. The lithium iron phosphate material anode sheet prepared by the preparation method disclosed by the invention is coated uniformly; the surface of the lithium iron phosphate material anode sheet is smooth and has no grains; the surface density is obviously improved; and a discharging specific capacity of a prepared semi-battery under a 0.1 C multiplying power is more than 145 mAh/g and a discharging specific capacity under a 1C multiplying power is more than 135 mAh/g. According to the preparation method disclosed by the invention, the performance of a pole sheet can be improved through optimizing a slurry formula and adding an additive for increasing the bonding property; and the operation process is simple and the cost is low. The preparation method has the very great propelling effect on the actual application of superfine lithium iron phosphate and nano-scale lithium iron phosphate.

Description

technical field [0001] The invention belongs to the technical field of lithium ion battery preparation, and in particular relates to a preparation method of a lithium iron phosphate material positive electrode sheet. Background technique [0002] Lithium iron phosphate (LiFePO 4 ) battery is a lithium-ion battery developed in recent years with good safety, long cycle life, low cost and environmental friendliness. It has been widely used in various backup power supplies, electric tools and electric bicycle power supplies, and is being demonstrated in the fields of electric vehicles, wind energy, solar energy, and smart grids. [0003] However, as the current industrialized lithium iron phosphate battery, in addition to the influence of the intrinsic properties of the lithium iron phosphate material on the electrochemical performance of the battery, the battery preparation process also has a great impact on the battery performance, especially the lithium iron phosphate positi...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M4/62H01M4/1397H01M10/0525
CPCY02E60/122Y02E60/10
Inventor 万水田蒲薇华高俊强
Owner 内蒙古三信科技发展有限公司
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