Preparation method of lithium iron phosphate positive electrode material slurry

A technology of lithium iron phosphate and positive electrode materials, which is applied in chemical instruments and methods, battery electrodes, phosphorus compounds, etc., and can solve problems such as high stirring speed requirements, large heat production, and difficulty in dispersing

Active Publication Date: 2015-06-03

WANXIANG 123 CO LTD

1 Cites 17 Cited by

AI-Extracted Technical Summary

Problems solved by technology

[0004] The invention aims to overcome the shortcomings of lithium iron phosphate positive electrode material that are not easy to disperse, require high stirring speed, a...

Abstract

The invention discloses a preparation method of a lithium iron phosphate positive electrode material slurry; the positive electrode material slurry is composed of lithium iron phosphate, a binder, a conductive agent and a solvent; the preparation method comprises the step of mixing the components in the positive electrode material slurry, wherein the mixing comprises four processes of adhesive solution preparation, conductive agent dispersion, lithium iron phosphate dispersion and dilution stabilizing. The conductive adhesive solution is added step by step into a lithium iron phosphate powder, and with use of shearing action of a device on a high-solid-content dispersion system, the acting force between particles and the acting force between the particles and the device are increased so as to achieve an excellent dispersion effect.

Application Domain

Cell electrodesSecondary cells +1

Technology Topic

SolventElectrode material +4

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Examples

Experimental program(3)

Example Embodiment

[0023] Example 1:

[0024] In a 50L planetary mixer, put 6 parts by weight of polyvinylidene fluoride powder into 69 parts by weight of N-methylpyrrolidone solvent, stir and wet at 15/300rpm at revolution/autobiography for 5 minutes, and then at revolution/autobiography Stirring and dispersing for 120 minutes at 25/1200 rpm, respectively, produced a glue solution with a solid content of 8%. Put 1 part by weight of vapor-grown carbon fiber and 3 parts by weight of conductive carbon black into the prepared glue, stir and wet at 15/300rpm for revolution/autobiography respectively for 5min, then stir at 25/1400 rpm for revolution/autobiography respectively Disperse for 30 minutes to obtain a conductive glue solution with a solid content of 12%. 100 parts by weight of lithium iron phosphate powder was put into a three-axis mixer, and the prepared conductive glue solution was divided into two equal parts. The first conductive glue solution was added to the three-axis mixer and dispersed for 30 minutes at a revolution/autobiography of 15/300 rpm respectively. Then add a second part of conductive glue solution, and disperse for 120 minutes at 25/800rpm for revolution/autobiography respectively. A slurry with a solid content of 61% was prepared. Then add 51 parts by weight of N-methylpyrrolidone to reduce the solid content to 48%, evacuate the mixer to -0.096MPa, stir and dilute at 25/1000rpm for 60 minutes at revolution/autobiography respectively, and stir evenly to obtain a suitable coating Lithium iron phosphate paste.

Example Embodiment

[0025] Example 2:

[0026] In a planetary mixer, put 5 parts by weight of polyvinylidene fluoride powder into 45 parts by weight of N-methylpyrrolidone solvent, stir and wet at 15/300rpm for 5 minutes at revolution/autobiography respectively, and then use revolution/autobiography respectively Stir and disperse at 25/1200 rpm for 120 minutes to obtain a glue with a solid content of 10%. Put 3 parts by weight of conductive carbon black into the prepared glue solution, stir and wet at 15/300rpm for revolution/autobiography respectively for 5min, and then stir and disperse for 30min at 25/1400 rpm for revolution/autobiography respectively to obtain a solid content of 15% conductive glue. 100 parts by weight of lithium iron phosphate powder was put into a three-axis mixer, the prepared conductive glue solution was divided into two equal parts, the first conductive glue solution was added to the three-axis mixer, and the revolution/autobiography were 15/400rpm for 30min dispersion. Then add a second part of conductive glue solution, and disperse for 120 minutes at 25/800rpm for revolution/autobiography respectively. A slurry with a solid content of 70% was prepared. Then add 55 parts by weight of N-methylpyrrolidone to reduce the solid content to 52%, evacuate the mixer to -0.095MPa, stir and dilute at 25/1000rpm for 60 minutes at revolution/autobiography, and stir evenly to obtain a suitable coating Lithium iron phosphate paste.

Example Embodiment

[0027] Example 3:

[0028] In a planetary mixer, put 7 parts by weight of polyvinylidene fluoride powder into 63 parts by weight of N-methylpyrrolidone solvent, stir and wet at 15/300rpm for 5 minutes at revolution/autobiography respectively, and then use revolution/autobiography respectively Stir and disperse at 25/1200 rpm for 120 minutes to obtain a glue with a solid content of 10%. Put 5 parts by weight of conductive carbon black into the glue solution, stir and wetting at 15/300rpm for revolution/autobiography respectively for 5min, and then stir and disperse for 30min at 25/1400 rpm for revolution/autobiography respectively to obtain a solid content of 16% conductive glue. 100 parts by weight of lithium iron phosphate powder is put into a three-axis mixer, the prepared conductive glue solution is divided into two equal parts, the first conductive glue solution is added to the three-axis mixer, and the revolution/autobiography are respectively 15/500rpm and dispersed for 30 minutes. Then add a second part of conductive glue, and disperse for 120 minutes at a revolution/autobiography of 25/1000rpm respectively. A slurry with a solid content of 64% was obtained. Then add 57 parts by weight of N-methylpyrrolidone to reduce the solid content to 48%, evacuate the mixer to -0.098MPa, stir and dilute at 25/1000rpm for 60 minutes at revolution/autobiography respectively, and stir evenly to obtain a suitable coating Lithium iron phosphate paste.

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