阅读说明：本技术 一种动力锂电池的隔膜材料 (Diaphragm material of power lithium battery ) 是由 胡伟 张德顺 李汪洋 吴磊 何祥燕 杨建军 张建安 陈曼 刘久逸 吴明元 吴庆云 于 2020-12-31 设计创作，主要内容包括：本发明涉及新材料加工技术领域,公开了一种动力锂电池的隔膜材料,将聚丙烯有机底膜浸渍在分散体中,该分散体系中含有的炭化玉米芯材料以及纳米级二氧化钛,炭化玉米芯材料中具有发达的三维孔道结构,可均匀的分散至二氧化钛醇溶液中,具有很强的吸附性能,进一步浸渍处理聚丙烯有机底膜,加工得到动力锂电池的隔膜材料,本发明制备得到的隔膜材料孔隙率高,孔径小,表面具有很好的力学性能和耐温性能,热收缩性好,使用安全性高,配合动力锂电池使用,具有大容量、高寿命、稳定均一输出等性能,为动力设备提供了足够的能量供应。(The invention relates to the technical field of new material processing, and discloses a diaphragm material of a power lithium battery.)

1. The diaphragm material of the power lithium battery is characterized in that the preparation method comprises the following steps:

(1) cleaning corncobs, placing the corncobs in an oven to dry until the water content is 6-9%, crushing, sieving with a 45-60-mesh sieve, then placing the corncobs in a sodium hydroxide solution to soak for 70-80 minutes at the soaking temperature of 30-32 ℃, filtering after soaking, placing the corncobs in the oven at the temperature of 70-80 ℃ to dry for 3-5 hours, sending the corncobs into a muffle furnace, heating to 550-570 ℃, preserving heat and carbonizing for 2-3 hours, continuing heating to 620-630 ℃, preserving heat for 10-15 minutes, naturally cooling to room temperature along with the furnace, and further grinding until the particle size is 0.4-0.8 micron;

(2) weighing 12.5-13.0 g of butyl titanate, placing the butyl titanate in a beaker, adding 33-36 ml of absolute ethyl alcohol in the beaker under the stirring at the speed of 200 plus 220 revolutions per minute, continuously stirring for 20-30 minutes, then adding 18-22 ml of acetic acid-ethanol mixed solution in the beaker, continuously stirring for 40-50 minutes, heating to 48-50 ℃, standing for 2-3 hours, then dropwise adding 5-6 ml of polyethylene glycol solvent in the beaker, then transferring to a hydrothermal reaction kettle, setting the reaction temperature to 200 plus 210 ℃, the reaction time to 14-16 hours, taking out the reaction kettle after the reaction, placing the reaction kettle in a ventilation cabinet, naturally cooling to room temperature, pouring out supernatant liquid, washing the obtained precipitate for 4-6 times by using ethanol and deionized water respectively, placing the precipitate in an oven at the temperature of 70-80 ℃ for drying for 6-8 hours, dispersing into absolute ethyl alcohol to form titanium dioxide alcoholic solution with mass fraction of 6.0-6.5%;

(3) adding the carbonized material prepared in the step (1) into the titanium dioxide alcohol solution prepared in the step (2), wherein the mass ratio of the material liquid to the alcohol solution is 1:7.0-7.4, rapidly stirring for 15-25 minutes at 600-650 rpm, then carrying out ultrasonic treatment for 2-3 minutes to obtain a dispersion, immersing the polypropylene organic basement membrane in the dispersion completely, soaking for 7-8 minutes at 30-35 ℃, taking out, drying for 8-10 hours at 55-60 ℃ under the condition that the relative humidity is 46-50%, and naturally cooling.

2. The separator material for lithium battery according to claim 1, wherein the concentration of the sodium hydroxide solution in step (1) is 4.0-4.5% by mass.

3. The separator material for a lithium battery according to claim 1, wherein the mass ratio of acetic acid to ethanol in the acetic acid-ethanol mixed solution in the step (2) is 1: 1.6-1.8.

4. The separator material for lithium battery according to claim 1, wherein the molecular weight of the polyethylene glycol in the step (2) is 400.

5. The separator material for a lithium-ion battery according to claim 1, wherein the particle size of the titanium dioxide in the alcoholic solution of titanium dioxide obtained in step (2) is between 16 and 30 nm.

Technical Field

The invention belongs to the technical field of new material processing, and particularly relates to a diaphragm material of a power lithium battery.

Background

In a mechanism consisting of a positive electrode, a diaphragm, an electrolyte and a negative electrode of the lithium ion battery, the cost of the diaphragm of the lithium ion battery accounts for about 1/3 of the cost of the battery, and the diaphragm is an electric insulating film with a porous structure and is a key inner-layer component of the lithium ion battery. The main function is to separate the positive and negative poles of the battery and prevent the two poles from direct contact and short circuit; the cell has the function of allowing ions to pass freely, and can also block current conduction in the cell through a closed-cell function when the cell is overheated. The performance of the separator determines the interface structure, internal resistance and the like of the battery, and directly influences the characteristics of the battery such as capacity, cycle performance, safety performance and the like.

At present, only a few countries such as the United states, Japan and the like have the production technical scheme of the lithium ion battery polymer diaphragm all over the world, and the large-scale production is realized. The lithium ion battery separator is started late in research and development of lithium ion battery separators in China, products still mainly depend on import, the average selling price of the separator is 8-15 yuan/square meter, the market price of the lithium ion battery is high, more than 80% of the separators in China are monopolized by the countries such as the United states, the Japanese and the like, and the domestic separators are mainly used in the middle-end and low-end markets. The battery diaphragm prepared by the dry method has low porosity and large aperture, and has the problems of uneven aperture distribution, general mechanical property, poor thermal shrinkage and the like.

Disclosure of Invention

The invention aims to provide a diaphragm material of a power lithium battery aiming at the existing problems, and the diaphragm material can meet the requirements of the power lithium battery in an all-round way.

The invention is realized by the following technical scheme:

the preferable scheme of the diaphragm material of the power lithium battery is that the preparation method of the diaphragm material comprises the following process steps:

(1) cleaning corncobs, placing the corncobs in an oven to dry until the water content is 6-9%, crushing, sieving with a 45-60-mesh sieve, then placing the corncobs in a sodium hydroxide solution with the mass concentration of 4.0-4.5% to soak for 70-80 minutes at the soaking temperature of 30-32 ℃, filtering after soaking, placing the corncobs in the oven with the temperature of 70-80 ℃ to dry for 3-5 hours, sending the corncobs into a muffle furnace, heating the corncobs to 550-570 ℃, carrying out heat preservation and carbonization for 2-3 hours, continuing heating the corncobs to 620-630 ℃, carrying out heat preservation for 10-15 minutes, naturally cooling the corncobs to room temperature along with the furnace, and further grinding the corncobs until the particle size is 0.4-;

(2) weighing 12.5-13.0 g of butyl titanate, placing the butyl titanate in a beaker, adding 33-36 ml of absolute ethyl alcohol in the beaker under the stirring at the speed of 200 plus 220 revolutions per minute, continuously stirring for 20-30 minutes, then adding 18-22 ml of acetic acid-ethanol mixed solution in the beaker, continuously stirring for 40-50 minutes, heating to 48-50 ℃, standing for 2-3 hours, then dropwise adding 5-6 ml of polyethylene glycol solvent in the beaker, then transferring to a hydrothermal reaction kettle, setting the reaction temperature to 200 plus 210 ℃, the reaction time to 14-16 hours, taking out the reaction kettle after the reaction, placing the reaction kettle in a ventilation cabinet, naturally cooling to room temperature, pouring out supernatant liquid, washing the obtained precipitate for 4-6 times by using ethanol and deionized water respectively, placing the precipitate in an oven at the temperature of 70-80 ℃ for drying for 6-8 hours, dispersing into absolute ethyl alcohol to form titanium dioxide alcoholic solution with mass fraction of 6.0-6.5%; in the acetic acid-ethanol mixed solution, the mass ratio of acetic acid to ethanol is 1: 1.6-1.8; the molecular weight of the polyethylene glycol is 400;

(3) adding the carbonized material prepared in the step (1) into the titanium dioxide alcohol solution prepared in the step (2), wherein the mass ratio of the material liquid to the alcohol solution is 1:7.0-7.4, rapidly stirring for 15-25 minutes at 600-650 rpm, then carrying out ultrasonic treatment for 2-3 minutes to obtain a dispersion, immersing the polypropylene organic basement membrane in the dispersion completely, soaking for 7-8 minutes at 30-35 ℃, taking out, drying for 8-10 hours at 55-60 ℃ under the condition that the relative humidity is 46-50%, and naturally cooling.

The grain size of the titanium dioxide in the prepared titanium dioxide alcohol solution is 16-30 nanometers.

Compared with the prior art, the invention has the following advantages: in order to solve the problem that the prior common lithium battery diaphragm material cannot meet the requirements of the performance of a power lithium battery, the invention provides the diaphragm material of the power lithium battery, which is prepared by dipping a polypropylene organic basement membrane in a dispersion, the carbonized corn core material and the nano-scale titanium dioxide contained in the dispersion system have developed three-dimensional pore canal structures, the prepared diaphragm material has high porosity, small aperture, good mechanical property and temperature resistance on the surface, good thermal shrinkage, high use safety, and the like, has the properties of large capacity, long service life, stability, uniformity, output and the like when being matched with a power lithium battery, and provides enough energy supply for power equipment.

Detailed Description

In order to make the objects, technical solutions and effects of the present invention clearer and clearer, the present invention is further described with reference to specific embodiments, and it should be understood that the specific embodiments described herein are only used for explaining the present invention and are not used for limiting the technical solutions provided by the present invention.

Example 1

A preparation method of a diaphragm material of a power lithium battery comprises the following process steps:

s1: cleaning corncobs, placing the corncobs in an oven to dry until the water content is 6-9%, crushing, sieving with a 45-mesh sieve, then placing the corncobs in a sodium hydroxide solution with the mass concentration of 4.0% to soak for 70 minutes at the soaking temperature of 30 ℃, filtering after soaking, placing the corncobs in the oven with the temperature of 70 ℃ to dry for 3 hours, sending the corncobs into a muffle furnace, heating to 550 ℃, carrying out heat preservation and carbonization for 2 hours, continuing heating to 620 ℃, carrying out heat preservation for 10 minutes, naturally cooling to room temperature along with the furnace, and further grinding until the particle size is 0.4-0.8 micron;

s2: weighing 12.5 g of butyl titanate, placing the butyl titanate in a beaker, adding 33 ml of absolute ethyl alcohol in the beaker under stirring at the speed of 200 revolutions per minute, continuously stirring for 20 minutes, then adding 18 ml of acetic acid-ethanol mixed solution in the beaker, continuously stirring for 40 minutes, heating to 48 ℃, standing for 2 hours, then dropwise adding 5 ml of polyethylene glycol solvent in the beaker, transferring the mixture to a hydrothermal reaction kettle, setting the reaction temperature to 200 ℃, the reaction time to 14 hours, taking out the reaction kettle after the reaction is finished, placing the reaction kettle in a ventilation cabinet, naturally cooling to room temperature, pouring out supernatant liquid, washing the obtained precipitate for 4 times respectively by using ethanol and deionized water, placing the precipitate in a 70 ℃ drying oven for drying for 6 hours, and dispersing the precipitate into absolute ethyl alcohol to form a titanium dioxide alcohol solution with the mass fraction of 6.0%; in the acetic acid-ethanol mixed solution, the mass ratio of acetic acid to ethanol is 1: 1.6; the molecular weight of the polyethylene glycol is 400;

s3: adding the carbonized material prepared in the step (1) into the titanium dioxide alcohol solution prepared in the step (2), wherein the mass ratio of the material liquid to the alcohol solution is 1:7.0, rapidly stirring for 15 minutes at 600 revolutions per minute, then carrying out ultrasonic treatment for 2 minutes to obtain a dispersion, immersing the polypropylene organic base membrane in the dispersion completely, immersing for 7 minutes at 30 ℃, taking out, drying for 8 hours at 55 ℃ and the relative humidity of 46%, and naturally cooling.

Further, the particle size of the titanium dioxide in the prepared titanium dioxide alcoholic solution is 16-30 nanometers.

Example 2

A preparation method of a diaphragm material of a power lithium battery comprises the following process steps:

s1: cleaning corncobs, placing the corncobs in an oven to dry until the water content is 6-9%, crushing, sieving with a 52-mesh sieve, then placing the corncobs in a sodium hydroxide solution with the mass concentration of 4.3% to soak for 75 minutes at the soaking temperature of 31 ℃, filtering after soaking, placing the corncobs in the oven with the temperature of 75 ℃ to dry for 4 hours, sending the corncobs into a muffle furnace, heating to 560 ℃, preserving heat and carbonizing for 2.5 hours, continuing heating to 625 ℃, preserving heat for 12 minutes, naturally cooling to room temperature along with the furnace, and further grinding until the particle size is 0.4-0.8 micron;

s2: weighing 12.8 g of butyl titanate, placing the butyl titanate in a beaker, adding 34 ml of absolute ethyl alcohol into the beaker under the stirring at the speed of 210 revolutions per minute, continuously stirring for 25 minutes, then adding 20 ml of acetic acid-ethanol mixed solution into the beaker, continuously stirring for 45 minutes, heating to 49 ℃, standing for 2.5 hours, then dropwise adding 5.5 ml of polyethylene glycol solvent into the beaker, then transferring the mixture into a hydrothermal reaction kettle, setting the reaction temperature to 205 ℃, the reaction time to 15 hours, taking out the reaction kettle after the reaction is finished, placing the reaction kettle in a ventilation cabinet to naturally cool to room temperature, pouring out supernatant liquid, washing the obtained precipitate with ethanol and deionized water for 5 times respectively, placing the precipitate in a 75 ℃ drying oven for 7 hours, and dispersing the dried alcohol solution into absolute ethyl alcohol to form titanium dioxide with the mass fraction of 6.2%; in the acetic acid-ethanol mixed solution, the mass ratio of acetic acid to ethanol is 1: 1.7; the molecular weight of the polyethylene glycol is 400;

s3: adding the carbonized material prepared in the step (1) into the titanium dioxide alcohol solution prepared in the step (2), wherein the mass ratio of the material liquid to the alcohol solution is 1:7.2, rapidly stirring for 20 minutes at 630 revolutions per minute, then carrying out ultrasonic treatment for 2.5 minutes to obtain a dispersion, immersing the polypropylene organic base membrane in the dispersion completely, soaking for 7.5 minutes at 32 ℃, taking out, drying for 9 hours at 58 ℃ under the condition that the relative humidity is 48%, and naturally cooling.

Further, the particle size of the titanium dioxide in the prepared titanium dioxide alcoholic solution is 16-30 nanometers.

Example 3

A preparation method of a diaphragm material of a power lithium battery comprises the following process steps:

s1: cleaning corncobs, placing the corncobs in an oven to dry until the water content is 6-9%, crushing, sieving with a 60-mesh sieve, then placing the corncobs in a sodium hydroxide solution with the mass concentration of 4.5% to soak for 80 minutes at the soaking temperature of 32 ℃, filtering after soaking, placing the corncobs in the oven at the temperature of 80 ℃ to dry for 5 hours, sending the corncobs into a muffle furnace, heating to 570 ℃, preserving heat and carbonizing for 3 hours, continuing heating to 630 ℃, preserving heat for 15 minutes, naturally cooling to room temperature along with the furnace, and further grinding until the particle size is 0.4-0.8 micron;

s2: weighing 13.0 g of butyl titanate, placing the butyl titanate in a beaker, adding 36 ml of absolute ethyl alcohol into the beaker under stirring at the speed of 220 revolutions per minute, continuously stirring for 30 minutes, then adding 22 ml of acetic acid-ethanol mixed solution into the beaker, continuously stirring for 50 minutes, heating to 50 ℃, standing for 3 hours, then dropwise adding 6 ml of polyethylene glycol solvent into the beaker, then transferring the mixture into a hydrothermal reaction kettle, setting the reaction temperature to 210 ℃ and the reaction time to 16 hours, taking out the reaction kettle after the reaction is finished, placing the reaction kettle in a ventilation cabinet, naturally cooling to room temperature, pouring out supernatant liquid, washing the obtained precipitate for 6 times by using ethanol and deionized water respectively, placing the precipitate in an oven at the temperature of 80 ℃ for drying for 8 hours, and dispersing the precipitate into absolute ethyl alcohol to form a titanium dioxide alcohol solution with the mass fraction of 6.5%; in the acetic acid-ethanol mixed solution, the mass ratio of acetic acid to ethanol is 1: 1.8; the molecular weight of the polyethylene glycol is 400;

s3: adding the carbonized material prepared in the step (1) into the titanium dioxide alcohol solution prepared in the step (2), wherein the mass ratio of the material liquid to the alcohol solution is 1:7.4, quickly stirring for 25 minutes at 650 revolutions per minute, then carrying out ultrasonic treatment for 3 minutes to obtain a dispersion, immersing the polypropylene organic base membrane in the dispersion completely, immersing for 8 minutes at 35 ℃, taking out, drying for 10 hours at 60 ℃ and the relative humidity of 50%, and naturally cooling.

Further, the particle size of the titanium dioxide in the prepared titanium dioxide alcoholic solution is 16-30 nanometers.

Comparative example 1

The difference from example 1 is that the preparation addition of the carbonized corncobs in step S1 is omitted, and the rest is kept consistent, and a power lithium battery diaphragm is prepared.

Comparative example 2

The difference from the embodiment 2 is that the preparation addition of the nano titanium dioxide in the step S2 is omitted, and the rest is consistent, so that the power lithium battery diaphragm is prepared.

Comparative example 3

The difference from example 3 is that a power lithium battery separator was prepared by using an equivalent amount of silica sol having a mass concentration of 28% instead of the titania alcohol solution described in example 3, and the rest was kept the same.

Control group

The porous polypropylene base membrane (thickness 25 μm, porosity 40%, average pore diameter 1.0 μm) prepared by the dry method was used as a power lithium battery separator.

Comparative experiment

The method comprises the following steps of preparing power lithium battery diaphragms according to the methods of examples 1-3, comparative examples 1-3 and a control group, preparing 5 samples in each group, and carrying out performance tests on the prepared diaphragm samples (the polypropylene organic base membranes adopted in the examples and the comparative examples are consistent with the control group), wherein the test standards are GB/T1040-2006 and GB/T12027-2004, independent variables are consistent in the tests, and the test results are shown in the following table:

the prepared diaphragm material has the advantages of high porosity, small pore diameter, uniform distribution, good mechanical property and temperature resistance on the surface, good thermal shrinkage, high use safety, high capacity, long service life, stable and uniform output and the like when being matched with a power lithium battery, and provides enough energy supply for power equipment.