CN115548581A - Lithium ion battery diaphragm with high ionic conductivity and preparation process thereof - Google Patents

Lithium ion battery diaphragm with high ionic conductivity and preparation process thereof Download PDF

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Publication number
CN115548581A
CN115548581A CN202211195858.9A CN202211195858A CN115548581A CN 115548581 A CN115548581 A CN 115548581A CN 202211195858 A CN202211195858 A CN 202211195858A CN 115548581 A CN115548581 A CN 115548581A
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nanotube
mos
lithium ion
ion battery
ionic conductivity
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李帆
张立斌
赵海玉
陈朝晖
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Jiangsu Housheng New Energy Technology Co Ltd
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Jiangsu Housheng New Energy Technology Co Ltd
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/40—Separators; Membranes; Diaphragms; Spacing elements inside cells
    • H01M50/409—Separators, membranes or diaphragms characterised by the material
    • H01M50/449—Separators, membranes or diaphragms characterised by the material having a layered structure
    • H01M50/457—Separators, membranes or diaphragms characterised by the material having a layered structure comprising three or more layers
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/40—Separators; Membranes; Diaphragms; Spacing elements inside cells
    • H01M50/403—Manufacturing processes of separators, membranes or diaphragms
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/40—Separators; Membranes; Diaphragms; Spacing elements inside cells
    • H01M50/409—Separators, membranes or diaphragms characterised by the material
    • H01M50/431—Inorganic material
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/40—Separators; Membranes; Diaphragms; Spacing elements inside cells
    • H01M50/489—Separators, membranes, diaphragms or spacing elements inside the cells, characterised by their physical properties, e.g. swelling degree, hydrophilicity or shut down properties
    • H01M50/497—Ionic conductivity
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/10—Energy storage using batteries

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  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Electrochemistry (AREA)
  • General Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Manufacturing & Machinery (AREA)
  • Inorganic Chemistry (AREA)
  • Cell Separators (AREA)

Abstract

The invention relates to the field of lithium ion batteries, in particular to a lithium ion battery diaphragm with high ionic conductivity and a preparation process thereof; the invention firstly prepares the MoS 2 The nano tube has good high temperature resistance and heat conduction performance, has a hollow structure, can effectively improve the conductivity of lithium ions, improves the surface area of the diaphragm and enhances the liquid absorption and retention capacity; on the basis, the invention further relates to MoS 2 Nanotube and flame retardant Mg (OH) 2 Through matching, moS with extremely high length-diameter ratio is prepared 2 Nanotube @ Mg (OH) 2 The coaxial composite material can form a mutually cross-linked net-shaped structure in the coating, thereby greatly improving the membrane machineIn addition, the invention also grafts methacrylic acid on the surface, and grafts carbon material on the surface by high-temperature carbonization, thereby enhancing the binding capacity of the invention and the COPNA resin adhesive and improving the performance of the diaphragm.

Description

Lithium ion battery diaphragm with high ionic conductivity and preparation process thereof
Technical Field
The invention relates to the technical field of lithium ion batteries, in particular to a lithium ion battery diaphragm with high ionic conductivity and a preparation process thereof.
Background
The polyolefin diaphragm is the most widely used diaphragm of the lithium battery at present, but the existing polyolefin diaphragm on the market has some disadvantages: (1) the ionic conductivity is low, so that the internal resistance of the battery is higher, and the charging and discharging of the lithium ion battery under the condition of high multiplying power are not facilitated; (2) the mechanical strength is low, the puncture resistance is poor, the battery is easy to puncture to cause the contact short circuit of the anode and the cathode of the battery, and thermal runaway is caused; (3) the melting point of the polyolefin material is very low, and the thermal runaway is more serious because the membrane is easily broken when the thermal runaway exists in the battery, so that the battery is burnt and even exploded; (4) the specific surface area is lower, and the liquid absorption and retention capacity is poorer. Aiming at the problems of low ionic conductivity, poor mechanical property and poor liquid absorption and retention capability of the polyolefin diaphragm, the main current solution is to coat a ceramic coating on one side or two sides of the polyolefin diaphragm; aiming at the problem of poor heat resistance of the polyolefin diaphragm, the high-temperature-resistant ceramic coating is coated on the surface of the polyolefin diaphragm, so that the pore closing of the diaphragm can be delayed to 150 ℃, but the pore closing temperature of 150 ℃ cannot completely avoid short circuit of a lithium battery at high temperature and spontaneous combustion caused by the short circuit, and therefore, the heat resistance of the diaphragm needs to be further improved, the risk of membrane rupture of the diaphragm is reduced, and the safety of the battery is improved. Therefore, the development of a lithium ion battery separator with high flame retardance, high electrolyte wettability and high ionic conductivity is a commonly pursued target in the industry.
Disclosure of Invention
The invention aims to provide a lithium ion battery diaphragm with high ionic conductivity and a preparation process thereof, so as to solve the problems in the background technology.
In order to solve the technical problems, the invention provides the following technical scheme: a lithium ion battery separator with high ionic conductivity has the following characteristics: the lithium ion battery diaphragm with high ionic conductivity consists of a base film and coating layers coated on two sides of the base film;
wherein the coating layer comprises the following components: 9-19% modified MoS 2 Nanotube @ Mg (OH) 2 Coaxial composite material, 0.2-0.6% of dispersing agent, 0.4-0.7% of thickening agent, 0.5-1% of adhesive, 0.05-0.2% of wetting agent and the balance of super-high-viscosity polyethylenePure water.
Further, the dispersant is hydrolyzed polymaleic anhydride (HPMA) dispersant; the thickening agent is a carboxymethyl cellulose sodium thickening agent.
Further, the adhesive is a COPNA resin adhesive; the wetting agent is a silanol nonionic surfactant.
Further, the modified MoS 2 Nanotube @ Mg (OH) 2 The coaxial composite material is made of MnCO 3 MnCO prepared from nanowires 3 The nanotube is prepared by reacting with magnesium sulfate and ammonia water, grafting methyl acrylate on the surface of the nanotube and calcining the nanotube;
wherein, mnCO 3 The nano-wire is prepared by the catalytic oxidation reaction of potassium permanganate and manganese chloride with hexadecyl trimethyl ammonium bromide and hydrogen peroxide.
A preparation process of a lithium ion battery diaphragm with high ionic conductivity comprises the following steps:
s1, preparing modified MoS 2 Nanotube @ Mg (OH) 2 A coaxial composite material;
s11, dissolving potassium permanganate and manganese chloride in deionized water, carrying out ultrasonic treatment for 20-30mim, adding hexadecyl trimethyl ammonium bromide and hydrogen peroxide, uniformly mixing, adding lithium carbonate, carrying out stirring reaction for 35-45min, heating to 180 ℃, carrying out high-temperature closed reaction for 18-24h, stopping heating after the reaction is finished, cooling to room temperature, filtering, alternately washing for 5-8 times by using absolute ethyl alcohol and deionized water, and carrying out vacuum drying to obtain MnCO 3 A nanowire;
s12, the MnCO prepared in the step S11 is subjected to 3 Dispersing the nano-wire into deionized water, dispersing and mixing for 2-3h, and adding Na 2 MoO 4 ·2H 2 Continuously dispersing O and L-cysteine for 1-2h, heating to 230-260 ℃, carrying out high-pressure closed reaction for 24-30h, stopping heating after the reaction is finished, cooling to room temperature, filtering, alternately washing with absolute ethyl alcohol and deionized water for 5-8 times, carrying out vacuum drying, soaking with hydrochloric acid for 36-48h, filtering, washing and precipitating to neutrality, and carrying out vacuum drying to obtain MoS 2 A nanotube;
MoS 2 the nanotube has a poleHigh length-diameter ratio, good heat conductivity and high temperature resistance, and MoS is used in coating slurry 2 Modified MoS with nanotube as matrix 2 Nanotube @ Mg (OH) 2 The coaxial composite material may utilize MoS 2 The high draw ratio of nanotube is crosslinked in the coating, forms 3-dimensional network structure to promote tensile resistance, strengthen its puncture resistance simultaneously, hinder the growth and the puncture of lithium dendrite, promote battery diaphragm's security performance.
S13, dissolving magnesium sulfate in ultrapure water to prepare a magnesium sulfate solution, and adding the MoS prepared in the step S12 2 Stirring and dispersing the nanotube for 40-60min, performing ultrasonic dispersion treatment for 3-4h, heating to 65-75 ℃, dropwise adding ammonia water, controlling the pH value of the reaction end point to be 8-10, filtering, alternately washing and precipitating by using absolute ethyl alcohol and ultrapure water to be neutral, and performing vacuum drying to obtain MoS 2 Nanotube @ Mg (OH) 2 A coaxial composite material;
Mg(OH) 2 the flame-retardant effect of (A) is derived from Mg (OH) 2 The crystal water is decomposed by heat and absorbs heat to form a carbonized layer. When the temperature rises to the decomposition temperature, mg (OH) 2 The water vapor is decomposed and released, latent heat is absorbed, and the concentration of oxygen and combustible gas near the surface of a combustion object is diluted, so that the surface combustion is difficult to carry out; the carbonized layer formed on the surface can prevent oxygen and heat from entering, and meanwhile, the magnesium oxide generated by decomposition of the carbonized layer is a good refractory material, has good high temperature resistance and heat conductivity, and can improve the capability of resisting open fire of the material.
S14, dissolving gamma-aminopropyl triethoxysilane in deionized water to prepare a gamma-aminopropyl triethoxysilane aqueous solution, and adding MoS 2 Nanotube @ Mg (OH) 2 Heating the coaxial composite material to 70-80 ℃, performing ultrasonic dispersion reaction for 12-18h, filtering, and collecting the filtered MoS 2 Nanotube @ Mg (OH) 2 Dispersing a coaxial composite material in ultrapure water, dropwise adding methyl acrylate, heating to 80-90 ℃, adding potassium persulfate, carrying out ultrasonic treatment reaction for 12-18h, filtering, protecting in an argon atmosphere, heating to 270-300 ℃, calcining for 1-2h, and cooling to room temperature to obtain the modified MoS 2 Nanotube @ Mg (OH) 2 A coaxial composite material;
the invention is also in MoS 2 Nanotube @ Mg (OH) 2 On the basis of the coaxial composite material, methyl acrylate is further grafted on the surface of the coaxial composite material. Firstly, the invention utilizes gamma-aminopropyl triethoxysilane in MoS 2 Nanotube @ Mg (OH) 2 Amino is grafted on the surface of the coaxial composite material, and methacrylic acid is grafted on the surface of the coaxial composite material by utilizing the amino with high reaction activity in the presence of potassium persulfate; then the invention carries out heating treatment on the resin, strictly limits the heating temperature in the argon atmosphere, carbonizes methacrylic acid on the surface of the resin at the decomposition temperature of materials such as magnesium hydroxide and the like, generates carbon materials on the surface, enhances the binding property of the rest COPNA resin and enhances the stability of the coating.
S2, modifying the MoS 2 Nanotube @ Mg (OH) 2 Adding the coaxial composite material and the dispersing agent into ultrapure water, premixing for 10-30min, adding the thickening agent, continuously dispersing for 20-60min, adding the binder, continuously mixing for 30-50min, adding the wetting agent, stirring for 20-40min, filtering for removing iron to obtain the modified MoS 2 Nanotube @ Mg (OH) 2 Coating the slurry;
s3, modifying the MoS 2 Nanotube @ Mg (OH) 2 Coating the coating slurry on two sides of the base film, baking for 1-3min at 70-80 ℃, and rolling to obtain the lithium ion battery diaphragm with high ionic conductivity.
Further, in the step S11, the mass ratio of potassium permanganate, manganese chloride and deionized water is (0.08-0.12): (0.25-0.3): (43-48).
Further, the mass ratio of the deionized water to the hexadecyl trimethyl ammonium bromide to the hydrogen peroxide to the lithium carbonate is (43-48): (0.12-0.15): (0.5-0.6): (0.09-0.12).
Further, in step S12, mnCO is added in parts by weight 3 Nanowire, deionized water, na 2 MoO 4 ·2H 2 The mass ratio of O to L-cysteine is (0.4-0.5): (75-80): (0.62-0.68): (2.5-2.8).
Further, in step S13, the concentration of the magnesium sulfate solution is 1.8-2.1mol/L; the concentration of ammonia water is 2-2.5mol/L.
Further, in step S14, gamma-aminopropyltriethoxysilane, moS are added in parts by weight 2 Nanotube @ Mg (OH) 2 The mass ratio of the coaxial composite material to the methyl acrylate to the potassium persulfate is (3.6-4.5): (1.2-1.56): (0.2-0.3): (0.02-0.03).
Compared with the prior art, the invention has the following beneficial effects: the invention firstly prepares the MoS 2 The nano tube has good high temperature resistance and heat conduction performance, has a hollow structure, can effectively improve the conductivity of lithium ions, improves the surface area of the diaphragm and enhances the liquid absorption and retention capacity; on the basis, the invention further relates to MoS 2 Nanotube and flame retardant Mg (OH) 2 Matching to prepare MoS with extremely high length-diameter ratio 2 Nanotube @ Mg (OH) 2 The coaxial composite material can form a mutually cross-linked net structure in the coating layer, thereby greatly improving the mechanical strength and the heat shrinkage performance of the diaphragm.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all embodiments. All other embodiments, which can be obtained by a person skilled in the art without making any creative effort based on the embodiments in the present invention, belong to the protection scope of the present invention.
In the comparative example of the embodiment of the invention, the thickening agent is sodium carboxymethyl cellulose; the dispersant is hydrolyzed maleic anhydride HPMA sold by Shandong Wanhuatian and New materials Co., ltd; the wetting agent is silanetriol trehalose ether; the polyolefin diaphragm is a PE film;
the adhesive is B-stage COPNA resin, and is prepared according to the content disclosed in the literature of' Jiangxing, chengxiang, songhuan, yueyongde, tangfeng, wangxing, yaxi and bamboo tar based COPNA resin synthesis and performance research [ J ] charcoal technology, 2016,35 (04): 41-44.DOI.
Example 1.
A preparation process of a lithium ion battery diaphragm with high ionic conductivity is characterized by comprising the following steps:
s1, preparing modified MoS 2 Nanotube @ Mg (OH) 2 A coaxial composite material;
s11, dissolving 0.088g of potassium permanganate and 0.267g of manganese chloride in 45ml of deionized water, performing ultrasonic treatment on 20mim, adding 0.13g of hexadecyl trimethyl ammonium bromide and 0.52ml of 30% hydrogen peroxide, uniformly mixing, adding 0.095g of lithium carbonate, stirring for reacting for 35min, transferring the mixed solution into a high-pressure reaction kettle with a polytetrafluoroethylene lining, then placing the high-pressure reaction kettle into an oven, keeping the temperature of the high-pressure reaction kettle at 180 ℃ for 20h, stopping heating after the reaction is finished, cooling to room temperature, filtering, alternately washing 5 times by using absolute ethyl alcohol and deionized water, and performing vacuum drying to obtain MnCO 3 A nanowire;
s12, 0.4138g of MnCO prepared in the step S11 is added 3 Dispersing the nano-wire into 78ml deionized water, stirring and mixing for 40min, then carrying out ultrasonic dispersion for 2h, adding 0.6533g Na 2 MoO 4 ·2H 2 O and 2.5080g of L-cysteine, continuously stirring for 20min, performing ultrasonic dispersion treatment for 40min, heating to 230 ℃, performing high-pressure closed reaction for 26h, stopping heating after the reaction is finished, cooling to room temperature, filtering, alternately washing for 5 times by using absolute ethyl alcohol and deionized water, performing vacuum drying, performing soaking treatment for 40h by using hydrochloric acid with the concentration of 2.0mol/L, filtering, washing and precipitating to be neutral, and drying for 12h at the temperature of 80 ℃ in vacuum to obtain MoS 2 A nanotube;
s13, magnesium sulfate is dissolved in 200ml of ultrapure water to prepare a magnesium sulfate solution with the concentration of 1.88mol/L, and 1.59g of MoS prepared in the step S12 is added 2 Stirring and dispersing the nanotube for 60min, performing ultrasonic dispersion treatment for 3h, heating to 70 ℃, dropwise adding 2mol/L ammonia water at a dropwise adding rate of 44ml/min, controlling the pH value of the reaction end point to be 8-10, filtering, alternately washing and precipitating to be neutral by using absolute ethyl alcohol and ultrapure water, drying for 12h at the temperature of 80 ℃ in vacuum to obtain MoS 2 Nanotube @ Mg (OH) 2 A coaxial composite material;
s14, dissolving 3.805g of gamma-aminopropyl triethoxysilane in 45ml of deionized water to prepare a gamma-aminopropyl triethoxysilane aqueous solution, and adding 1.59g of MoS 2 Nanotube @ Mg (OH) 2 Heating the coaxial composite material to 75 ℃, performing ultrasonic dispersion reaction for 16h, filtering, and collecting the filtered MoS 2 Nanotube @ Mg (OH) 2 Dispersing the coaxial composite material in ultrapure water, dropwise adding 0.252g of methyl acrylate, heating to 85 ℃, adding 0.02g of potassium persulfate, carrying out ultrasonic treatment reaction for 12 hours, filtering, protecting in argon atmosphere, heating to 270 ℃, calcining for 1 hour, and cooling to room temperature to obtain the modified MoS 2 Nanotube @ Mg (OH) 2 A coaxial composite material;
s2, modifying 9g of MoS 2 Nanotube @ Mg (OH) 2 Adding a coaxial composite material and 0.2g of dispersing agent into 89.23g of ultrapure water, premixing at 300rpm for 30min, adding 0.66g of thickening agent, continuing to disperse at 400rpm for 45min, adding 0.79g of binding agent, continuing to mix at 420rpm for 40min, adding 0.12g of wetting agent, stirring at 550rpm for 35min, filtering to remove iron, and thus obtaining the modified MoS 2 Nanotube @ Mg (OH) 2 Coating the slurry;
s3, modifying the MoS 2 Nanotube @ Mg (OH) 2 Coating the coating slurry on two sides of a polyolefin diaphragm with the thickness of 9 mu m, wherein the thickness of one side coating is 3 mu m, baking for 3min at 70 ℃, and rolling to obtain the lithium ion battery diaphragm with high ionic conductivity.
Example 2.
This example adds the modified MoS in step S2 compared to example 1 2 Nanotube @ Mg (OH) 2 The addition amount of the coaxial composite material;
a preparation process of a lithium ion battery diaphragm with high ionic conductivity is characterized by comprising the following steps:
s1, preparing modified MoS 2 Nanotube @ Mg (OH) 2 A coaxial composite material;
s11, dissolving 0.088g of potassium permanganate and 0.267g of manganese chloride in 45ml of deionized water, carrying out ultrasonic treatment on 20mim, adding 0.13g of hexadecyl trimethyl ammonium bromide and 0.52ml of 30% hydrogen peroxide, uniformly mixing, adding 0.095g of lithium carbonate, stirring for reacting for 35min, and dissolving the mixtureTransferring the solution into a high-pressure reaction kettle with a polytetrafluoroethylene lining, then placing the reaction kettle in an oven, keeping the temperature at 180 ℃ for 20 hours, stopping heating after the reaction is finished, cooling to room temperature, filtering, alternately washing with absolute ethyl alcohol and deionized water for 5 times, and drying in vacuum to obtain MnCO 3 A nanowire;
s12, 0.4138g of MnCO prepared in the step S11 is added 3 Dispersing the nano-wire into 78ml deionized water, stirring and mixing for 40min, then carrying out ultrasonic dispersion for 2h, adding 0.6533g Na 2 MoO 4 ·2H 2 O and 2.5080g of L-cysteine, continuously stirring for 20min, performing ultrasonic dispersion treatment for 40min, heating to 230 ℃, performing high-pressure closed reaction for 26h, stopping heating after the reaction is finished, cooling to room temperature, filtering, alternately washing for 5 times by using absolute ethyl alcohol and deionized water, performing vacuum drying, soaking for 40h by using hydrochloric acid with the concentration of 2.0mol/L, filtering, washing and precipitating to be neutral, and drying for 12h at the temperature of 80 ℃ in vacuum to obtain MoS 2 A nanotube;
s13, dissolving magnesium sulfate in 200ml of ultrapure water to prepare a magnesium sulfate solution with the concentration of 1.88mol/L, and adding 1.59g of MoS prepared in the step S12 2 Stirring and dispersing the nanotube for 60min, performing ultrasonic dispersion treatment for 3h, heating to 70 ℃, dropwise adding ammonia water with the concentration of 2mol/L at the dropping speed of 44ml/min, controlling the pH value of the reaction end point to be 8-10, filtering, alternately washing and precipitating to be neutral by using absolute ethyl alcohol and ultrapure water, drying for 12h at the temperature of 80 ℃ in vacuum to obtain MoS 2 Nanotube @ Mg (OH) 2 A coaxial composite material;
s14, dissolving 3.805g of gamma-aminopropyl triethoxysilane in 45ml of deionized water to prepare a gamma-aminopropyl triethoxysilane aqueous solution, and adding 1.59g of MoS 2 Nanotube @ Mg (OH) 2 Heating the coaxial composite material to 75 ℃, performing ultrasonic dispersion reaction for 16h, filtering, and collecting the filtered MoS 2 Nanotube @ Mg (OH) 2 Dispersing a coaxial composite material in ultrapure water, dropwise adding 0.252g of methyl acrylate, heating to 85 ℃, adding 0.02g of potassium persulfate, carrying out ultrasonic treatment reaction for 12 hours, filtering, protecting in an argon atmosphere, heating to 270 ℃, calcining for 1 hour, and cooling to room temperature to obtain the modified MoS 2 Nanotube @ Mg (OH) 2 A coaxial composite material;
s2, modifying 14g of MoS 2 Nanotube @ Mg (OH) 2 Adding a coaxial composite material and 0.2g of dispersing agent into 84.23g of ultrapure water, premixing at 300rpm for 30min, adding 0.66g of thickening agent, continuing to disperse at 400rpm for 45min, adding 0.79g of binding agent, continuing to mix at 420rpm for 40min, adding 0.12g of wetting agent, stirring at 550rpm for 35min, filtering to remove iron, and thus obtaining the modified MoS 2 Nanotube @ Mg (OH) 2 Coating the slurry;
s3, modifying the MoS 2 Nanotube @ Mg (OH) 2 Coating the slurry on two sides of a polyolefin diaphragm with the thickness of 9 mu m, wherein the thickness of the coating on one side is 3 mu m, baking at 70 ℃ for 3min, and rolling to obtain the lithium ion battery diaphragm with high ionic conductivity.
Example 3.
This example added the modified MoS in step S2 compared to example 1 2 Nanotube @ Mg (OH) 2 The addition amount of the coaxial composite material;
a preparation process of a lithium ion battery diaphragm with high ionic conductivity is characterized by comprising the following steps:
s1, preparing modified MoS 2 Nanotube @ Mg (OH) 2 A coaxial composite material;
s11, dissolving 0.088g of potassium permanganate and 0.267g of manganese chloride in 45ml of deionized water, performing ultrasonic treatment on 20mim, adding 0.13g of hexadecyl trimethyl ammonium bromide and 0.52ml of 30% hydrogen peroxide, uniformly mixing, adding 0.095g of lithium carbonate, stirring for reacting for 35min, transferring the mixed solution into a high-pressure reaction kettle with a polytetrafluoroethylene lining, then placing the high-pressure reaction kettle into an oven, keeping the temperature of the high-pressure reaction kettle at 180 ℃ for 20h, stopping heating after the reaction is finished, cooling to room temperature, filtering, alternately washing 5 times by using absolute ethyl alcohol and deionized water, and performing vacuum drying to obtain MnCO 3 A nanowire;
s12, mixing 0.4138g of MnCO prepared in the step S11 3 Dispersing the nano-wire into 78ml deionized water, stirring and mixing for 40min, then carrying out ultrasonic dispersion for 2h, adding 0.6533g Na 2 MoO 4 ·2H 2 O and 2.5080g of L-cysteine, continuously stirring for 20min, performing ultrasonic dispersion treatment for 40min, heating to 230 ℃, performing high-pressure closed reaction for 26h, and stopping after the reaction is finishedStopping heating, cooling to room temperature, filtering, alternately washing with anhydrous ethanol and deionized water for 5 times, vacuum drying, soaking with 2.0mol/L hydrochloric acid for 40 hr, filtering, washing precipitate to neutrality, vacuum drying at 80 deg.C for 12 hr to obtain MoS 2 A nanotube;
s13, magnesium sulfate is dissolved in 200ml of ultrapure water to prepare a magnesium sulfate solution with the concentration of 1.88mol/L, and 1.59g of MoS prepared in the step S12 is added 2 Stirring and dispersing the nanotube for 60min, performing ultrasonic dispersion treatment for 3h, heating to 70 ℃, dropwise adding ammonia water with the concentration of 2mol/L at the dropping speed of 44ml/min, controlling the pH value of the reaction end point to be 8-10, filtering, alternately washing and precipitating to be neutral by using absolute ethyl alcohol and ultrapure water, drying for 12h at the temperature of 80 ℃ in vacuum to obtain MoS 2 Nanotube @ Mg (OH) 2 A coaxial composite material;
s14, dissolving 3.805g of gamma-aminopropyl triethoxysilane in 45ml of deionized water to prepare a gamma-aminopropyl triethoxysilane aqueous solution, and adding 1.59g of MoS 2 Nanotube @ Mg (OH) 2 Heating the coaxial composite material to 75 ℃, performing ultrasonic dispersion reaction for 16h, filtering, and collecting the filtered MoS 2 Nanotube @ Mg (OH) 2 Dispersing the coaxial composite material in ultrapure water, dropwise adding 0.252g of methyl acrylate, heating to 85 ℃, adding 0.02g of potassium persulfate, carrying out ultrasonic treatment reaction for 12 hours, filtering, protecting in argon atmosphere, heating to 270 ℃, calcining for 1 hour, and cooling to room temperature to obtain the modified MoS 2 Nanotube @ Mg (OH) 2 A coaxial composite material;
s2, modifying 19g of modified MoS 2 Nanotube @ Mg (OH) 2 Adding a coaxial composite material and 0.2g of dispersing agent into 79.23g of ultrapure water, premixing at 300rpm for 30min, adding 0.66g of thickening agent, continuously dispersing at 400rpm for 45min, adding 0.79g of binding agent, continuously mixing at 420rpm for 40min, adding 0.12g of wetting agent, stirring at 550rpm for 35min, filtering to remove iron, and thus obtaining the modified MoS 2 Nanotube @ Mg (OH) 2 Coating the slurry;
s3, modifying the MoS 2 Nanotube @ Mg (OH) 2 Coating slurry on both sides of a polyolefin diaphragm with the thickness of 9 mu m, wherein the thickness of a single-side coating is 3 mu m, baking at 70 ℃ for 3min, and rolling to obtain the lithium ion battery with high ionic conductivityA cell membrane.
Comparative example 1.
This comparative example used only a polyolefin separator as a coating layer as a lithium ion battery separator.
And (3) detection: examples 1-3 and comparative example 1 were tested according to the test standard GB/T36363-2018, and the air permeability was measured by a Gurley air permeameter, and the peel strength and the puncture strength were measured by a universal tester;
the liquid absorption rate test method comprises the following steps: preparing a battery diaphragm into a sample of 50mm multiplied by 50mm, drying for 24 hours, taking out and weighing, and recording as M; it was immersed in a beaker containing the electrolyte, taken out after 10 minutes of immersion and immediately weighed, recorded as M1. The liquid absorption rate is measured by mass fraction, namely the liquid absorption rate = (M1-M)/M;
the liquid retention rate detection method comprises the following steps: preparing a battery diaphragm into a sample of 50mm multiplied by 50mm, drying for 24 hours, taking out and weighing, and recording as M; immersing the mixture in a beaker filled with electrolyte, taking out after soaking for 10 minutes, suspending the mixture for 3 minutes to remove part of the electrolyte, weighing, and recording as M2. The liquid absorption rate is measured by mass fraction, namely the liquid absorption rate = (M2-M)/M;
specific data are shown in the following table;
Figure BDA0003870580240000081
from the above, it can be seen that:
as can be seen by comparing examples 1 to 3 with comparative example 1, moS 2 Nanotube @ Mg (OH) 2 The mechanical strength (needling strength) of the diaphragm is greatly improved by the modification of (2); when examples 1 to 3 and comparative example 1 were compared, it was found that MoS was contained in the slurry 2 Nanotube @ Mg (OH) 2 When the mass ratio of the composite diaphragm is gradually increased from 9% to 19%, the liquid absorption rate and the liquid retention rate of the corresponding composite diaphragm are better and better, namely the wettability of the electrolyte is better and better, and the wettability of the electrolyte is far higher than that of a pure polyolefin diaphragm without a coating, and the MoS is proved 2 Nanotube @ Mg (OH) 2 The electrolyte wettability of the diaphragm can be effectively improved through the modification; when examples 1 to 3 and comparative example 1 were compared, it was found that MoS was contained in the slurry 2 Nano-meterPipe @ Mg (OH) 2 When the mass ratio of (2) is gradually increased from 9% to 19%, the ionic conductivity of the corresponding composite diaphragm is higher and higher, and the ionic conductivity is far higher than that of a pure polyolefin diaphragm without a coating layer, and the MoS is proved 2 Nanotube @ Mg (OH) 2 The modification of (2) can effectively improve the ionic conductivity of the diaphragm; comparing examples 1-3 with comparative example 1, it can be seen that MoS is present in the slurry 2 Nanotube @ Mg (OH) 2 When the mass ratio of the composite membrane is gradually increased from 9% to 19%, the thermal shrinkage performance of the corresponding composite membrane is better and better, and the composite membrane is far superior to a pure polyolefin membrane without a coating, and the MoS is proved 2 Nanotube @ Mg (OH) 2 The heat resistance is improved.
Comparing examples 1-3 with comparative example 1, it can be seen that MoS is present in the slurry 2 Nanotube @ Mg (OH) 2 When the mass ratio of (2) is gradually increased from 9% to 14%, the air permeability of the corresponding composite membrane is deteriorated, and when MoS is used 2 Nanotube @ Mg (OH) 2 When the mass ratio of (b) is further increased to 19%, the air permeability of the corresponding composite separator is seriously deteriorated and is inferior to that of a pure polyolefin separator without coating, and thus MoS is a trade-off in various properties of the composite separator 2 Nanotube @ Mg (OH) 2 The amount of (A) is moderate, and more is not preferable; by comparing examples 1-3 with comparative example 1, moS 2 Nanotube @ Mg (OH) 2 The oxygen index of the modified composite separator was much greater than that of the uncoated pure polyolefin separator, confirming MoS 2 Nanotube @ Mg (OH) 2 The flame retardant property of the diaphragm can be effectively improved.
Finally, it should be noted that: although the present invention has been described in detail with reference to the foregoing embodiments, it will be apparent to those skilled in the art that changes may be made in the embodiments and/or equivalents thereof without departing from the spirit and scope of the invention. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims (10)

1. A lithium ion battery separator with high ionic conductivity is characterized in that: the lithium ion battery diaphragm with high ionic conductivity consists of a base film and coating layers coated on two sides of the base film;
wherein the coating layer comprises the following components: 9-19% modified MoS 2 Nanotube @ Mg (OH) 2 The composite material comprises a coaxial composite material, 0.2-0.6% of a dispersing agent, 0.4-0.7% of a thickening agent, 0.5-1% of an adhesive, 0.05-0.2% of a wetting agent and the balance of ultrapure water.
2. The high ionic conductivity lithium ion battery separator according to claim 1, wherein: the dispersant is hydrolyzed polymaleic anhydride (HPMA) dispersant; the thickening agent is a carboxymethyl cellulose sodium thickening agent.
3. The high ionic conductivity lithium ion battery separator according to claim 1, wherein: the adhesive is a COPNA resin adhesive; the wetting agent is a silanol nonionic surfactant.
4. The lithium ion battery separator with high ionic conductivity according to claim 1, wherein: the modified MoS 2 Nanotube @ Mg (OH) 2 The coaxial composite material is made of MnCO 3 MnCO prepared from nanowires 3 The nanotube is prepared by reacting with magnesium sulfate and ammonia water, grafting methyl acrylate on the surface of the nanotube and calcining the nanotube;
wherein, mnCO 3 The nano-wire is prepared by the catalytic oxidation reaction of potassium permanganate and manganese chloride with hexadecyl trimethyl ammonium bromide and hydrogen peroxide.
5. A preparation process of a lithium ion battery diaphragm with high ionic conductivity is characterized by comprising the following steps:
s1, preparing modified MoS 2 Nanotube @ Mg (OH) 2 A coaxial composite material;
s11, dissolving potassium permanganate and manganese chloride in deionized water, and performing ultrasonic treatmentTreating for 20-30mimn, adding hexadecyl trimethyl ammonium bromide and hydrogen peroxide, uniformly mixing, adding lithium carbonate, stirring and reacting for 35-45min, heating to 180 ℃, carrying out high-temperature closed reaction for 18-24h, stopping heating after the reaction is finished, cooling to room temperature, filtering, alternately washing for 5-8 times by using absolute ethyl alcohol and deionized water, and carrying out vacuum drying to obtain MnCO 3 A nanowire;
s12, the MnCO prepared in the step S11 is added 3 Dispersing the nano-wire into deionized water, dispersing and mixing for 2-3h, and adding Na 2 MoO 4 ·2H 2 Continuously dispersing O and L-cysteine for 1-2h, heating to 230-260 ℃, carrying out high-pressure closed reaction for 24-30h, stopping heating after the reaction is finished, cooling to room temperature, filtering, alternately washing with absolute ethyl alcohol and deionized water for 5-8 times, carrying out vacuum drying, soaking with hydrochloric acid for 36-48h, filtering, washing and precipitating to neutrality, and carrying out vacuum drying to obtain MoS 2 A nanotube;
s13, dissolving magnesium sulfate in ultrapure water to prepare a magnesium sulfate solution, and adding the MoS prepared in the step S12 2 The method comprises the steps of dispersing nanotubes for 40-60min by stirring, performing ultrasonic dispersion treatment for 3-4h, heating to 65-75 ℃, dropwise adding ammonia water, controlling the pH value of the reaction end point to be 8-10, filtering, alternately washing the precipitate to be neutral by using absolute ethyl alcohol and ultrapure water, and performing vacuum drying to obtain MoS 2 Nanotube @ Mg (OH) 2 A coaxial composite material;
s14, dissolving gamma-aminopropyl triethoxysilane in deionized water to prepare a gamma-aminopropyl triethoxysilane aqueous solution, and adding MoS 2 Nanotube @ Mg (OH) 2 Heating the coaxial composite material to 70-80 ℃, performing ultrasonic dispersion reaction for 12-18h, filtering, and collecting the filtered MoS 2 Nanotube @ Mg (OH) 2 Dispersing a coaxial composite material in ultrapure water, dropwise adding methyl acrylate, heating to 80-90 ℃, adding potassium persulfate, carrying out ultrasonic treatment reaction for 12-18h, filtering, protecting in an argon atmosphere, heating to 270-300 ℃, calcining for 1-2h, and cooling to room temperature to obtain the modified MoS 2 Nanotube @ Mg (OH) 2 A coaxial composite material;
s2, modifying the MoS 2 Nanotube @ Mg (OH) 2 Coaxial composite material and dispersant additionPremixing ultrapure water for 10-30min, adding thickener, continuously dispersing for 20-60min, adding binder, continuously mixing for 30-50min, adding wetting agent, stirring for 20-40min, filtering to remove iron to obtain modified MoS 2 Nanotube @ Mg (OH) 2 Coating the slurry;
s3, modifying the MoS 2 Nanotube @ Mg (OH) 2 Coating the coating slurry on two sides of the base film, baking for 1-3min at 70-80 ℃, and rolling to obtain the lithium ion battery diaphragm with high ionic conductivity.
6. The preparation process of the lithium ion battery separator with high ionic conductivity according to claim 5, wherein the preparation process comprises the following steps: in step S11, the mass ratio of potassium permanganate, manganese chloride and deionized water is (0.08-0.12): (0.25-0.3): (43-48).
7. The preparation process of the lithium ion battery separator with high ionic conductivity according to claim 5, wherein the preparation process comprises the following steps: the mass ratio of the deionized water to the hexadecyl trimethyl ammonium bromide to the hydrogen peroxide to the lithium carbonate is (43-48): (0.12-0.15): (0.5-0.6): (0.09-0.12).
8. The preparation process of the lithium ion battery separator with high ionic conductivity according to claim 5, wherein the preparation process comprises the following steps: in step S12, in parts by weight, mnCO 3 Nanowire, deionized water, na 2 MoO 4 ·2H 2 The mass ratio of O to L-cysteine is (0.4-0.5): (75-80): (0.62-0.68): (2.5-2.8).
9. The preparation process of the lithium ion battery separator with high ionic conductivity according to claim 5, wherein the preparation process comprises the following steps: in step S13, the concentration of the magnesium sulfate solution is 1.8-2.1mol/L; the concentration of ammonia water is 2-2.5mol/L.
10. The preparation process of the lithium ion battery separator with high ionic conductivity according to claim 5, wherein the preparation process comprises the following steps: in step S14, in parts by weight, a gamma-aminopropyl groupTriethoxysilane, moS 2 Nanotube @ Mg (OH) 2 The mass ratio of the coaxial composite material to the methyl acrylate to the potassium persulfate is (3.6-4.5): (1.2-1.56): (0.2-0.3): (0.02-0.03).
CN202211195858.9A 2022-09-29 2022-09-29 Lithium ion battery diaphragm with high ionic conductivity and preparation process thereof Pending CN115548581A (en)

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