Li-ion positive electrode slurry and preparation method thereof

A cathode slurry, lithium ion technology, used in battery electrodes, electrical components, circuits, etc., can solve the problems of poor slurry conductivity, poor slurry stability, and poor slurry uniformity, and achieve sedimentation. Small, good pulping effect, good uniformity effect

Inactive Publication Date: 2013-10-09
IRICO
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The preparation process is simple and easy, but it also has the following disadvantages: 1) Due to the difference in particle size and bulk density between the positive electrode material and the conductive agent, the uniformity of the slurry is not good; 2) The conductivity of the slurry is not good, The conductive agent is easy to agglomerate; 3) The stability of the slurry is not good, and the slurry is easy to settle after 2-5 hours

Method used

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  • Li-ion positive electrode slurry and preparation method thereof
  • Li-ion positive electrode slurry and preparation method thereof

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Experimental program
Comparison scheme
Effect test

Embodiment 1

[0032] 1) Weigh lithium iron phosphate, polyvinylidene fluoride, Super-P material and KS-6 respectively according to the mass ratio of 90:7:2:1;

[0033] 2) Dry powder mixing:

[0034] Clean and dry the slurry tank of the planetary mixer, add lithium iron phosphate, Super-P material and KS-6, then dry mix at a revolution speed of 5rpm and a stirring speed of 10rpm for 30min, and keep the stirring temperature at 20-40°C, and according to the situation, the stirring blade and the slurry tank need to be scraped in time to make the obtained dry powder mixture evenly mixed; during the stirring process, the lithium iron phosphate, Super-P material and KS are being mixed from the slurry tank -6 and 10 samples were randomly sampled from all directions in the inorganic conductive agent, and the powder resistance values ​​of these 10 samples were tested respectively. The deviation of the powder resistance value of each sample was less than 5%. At this time, it was considered to be unifo...

Embodiment 2

[0044] Step 1) to step 2) are the same as step 1) to step 2) in the embodiment;

[0045] 3) Step-by-step slurry preparation process:

[0046] According to the mass ratio of 8:100, dissolve polyvinylidene fluoride into N-methylpyrrolidone at 20-40°C to obtain PVDF colloidal liquid; divide PVDF colloidal liquid into four parts, and the first part of PVDF colloidal liquid Accounting for 32% of the total mass of PVDF jelly, the second PVDF jelly accounts for 15% of the total PVDF jelly, the third PVDF jelly accounts for 28% of the total PVDF jelly, and the fourth PVDF Colloidal liquid accounts for 25% of the total mass of PVDF colloidal liquid;

[0047] Add the first part of PVDF colloidal liquid to the dry powder mixture, and then stir at a revolution speed of 15rpm and a stirring speed of 28rpm at 20-40°C for 30min to make it uniform, and obtain a mixed slurry A; wherein, during the stirring process, according to the situation The stirring paddle and the slurry tank are scrape...

Embodiment 3

[0054] Step 1) to step 2) are the same as step 1) to step 2) in the embodiment;

[0055] 3) Step-by-step slurry preparation process:

[0056] According to the mass ratio of 8:100, dissolve polyvinylidene fluoride into N-methylpyrrolidone at 20-40°C to obtain PVDF colloidal liquid; divide PVDF colloidal liquid into four parts, and the first part of PVDF colloidal liquid Accounting for 35% of the total mass of PVDF gel, the second PVDF gel accounts for 18% of the total mass of PVDF gel, the third PVDF gel accounts for 30% of the total mass of PVDF gel, and the fourth PVDF Colloidal liquid accounts for 17% of the total mass of PVDF colloidal liquid;

[0057] Add the first part of PVDF colloidal liquid to the dry powder mixture, and then stir at 20-40°C at a revolution speed of 20rpm and a stirring speed of 35rpm for 40min to make the mixed slurry A uniform; The stirring paddle and the slurry tank are scraped in good time so that there is no dry powder in the obtained mixed slur...

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Abstract

The invention provides a Li-ion positive electrode slurry and a preparation method thereof. The preparation method comprises the following steps of: mixing lithium iron phosphate and dry inorganic conductive agent powder, wherein uniform mixing is judged by randomly sampling and measuring the resistance value of the powder, and is considered to be achieved when the difference of the resistance value of each sample powder is less than 5%; then adding PVDF (Polyvinylidene Fluoride) colloidal fluid into the mixture step by step; finally regulating the viscosity of the slurry by utilizing 1-Methyl-2-pyrrolidinone, thereby obtaining the Li-ion positive electrode slurry. The viscosity of the Li-ion positive electrode slurry is 3000-5000cps, and the Li-ion positive electrode slurry comprises 1-methyl-2-pyrrolidinone, as well as lithium iron phosphate, polyvinylidene fluoride and the inorganic conductive agent which are at a mass ratio of (85-95):(3-8):(2-10). According to the preparation method, whether the inorganic conductive agent is uniformly dispersed in lithium iron phosphate is determined by a method of randomly sampling dry powder, mixing samples and measuring the resistance values, and meanwhile, the PVDF colloidal fluid is added step by step in a substep slurry preparation process, so that the conventional thought of firstly mixing solid materials and adding the colloidal fluid in one step in a slurry preparation process in the field is broken through, and a favorable slurry preparation effect is achieved.

Description

technical field [0001] The invention belongs to the technical field of lithium ion batteries, and in particular relates to a lithium ion positive electrode slurry and a preparation method thereof. Background technique [0002] Lithium is the lightest element among metals, and its electrode potential is -3.045V, which is the most negative element among metal elements. Therefore, it has been greatly concerned by chemical power scientists for a long time. The deintercalation of lithium ions from the carbon material lattice occurs at an electrode potential close to metallic lithium (positive than the lithium electrode potential), and LiCoO 2 The electrode potential of the positive electrode reaction is about 4.0V (relative to the lithium electrode), so this new battery has a high working voltage and a high specific energy. In addition, it has the characteristics of low self-discharge rate, long cycle life, no memory effect and no pollution. [0003] Lithium-ion battery cathod...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M4/58H01M4/62
CPCY02E60/10
Inventor 高洪森
Owner IRICO
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