CN213026385U - Lithium ion battery is with multi-functional two-sided heterogeneous Janus diaphragm - Google Patents

Lithium ion battery is with multi-functional two-sided heterogeneous Janus diaphragm Download PDF

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CN213026385U
CN213026385U CN202021743442.2U CN202021743442U CN213026385U CN 213026385 U CN213026385 U CN 213026385U CN 202021743442 U CN202021743442 U CN 202021743442U CN 213026385 U CN213026385 U CN 213026385U
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王杰
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Beijing Yucheng Technology Co ltd
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Abstract

Disclosed herein is a multifunctional double-sided heterogeneous Janus separator for a lithium ion battery. The double-sided heterogeneous Janus diaphragm is formed by compounding a polyolefin single-sided inorganic coating diaphragm layer, a bonding layer and a high-temperature-resistant polymer nanofiber film layer which are sequentially arranged, wherein the bonding layer and the nanofiber film layer are positioned on one side of the polyolefin diaphragm, which is not an inorganic coating; the thickness of the polyolefin single-sided inorganic coating diaphragm is 4-25 mu m; the thickness of the high-temperature resistant polymer nanofiber membrane is 0.4-11 mu m; the thickness of the bonding layer is 0.4-4 μm; the total thickness of the Janus diaphragm is 5-40 mu m. In the composite diaphragm, the inorganic coating can improve the whole lithium dendrite puncture resistance of the diaphragm, the nanofiber layer provides high-temperature dimensional stability and high liquid retention property, and the polyolefin diaphragm can play a hole closing role at high temperature to block lithium ion transmission. The utility model discloses process is simple and easy, and bonding strength is high between nanofiber layer and the polyolefin diaphragm layer, and thermal dimension stability and electrolyte infiltration nature are excellent, and application prospect is good.

Description

Lithium ion battery is with multi-functional two-sided heterogeneous Janus diaphragm
Technical Field
The utility model belongs to the technical field of novel lithium ion battery diaphragm, especially, relate to a lithium ion battery is with multi-functional two-sided heterogeneous Janus diaphragm.
Background
The lithium ion battery diaphragm is an important component in the lithium ion battery, on one hand, the ion transmission is ensured, and on the other hand, the anode and the cathode are isolated to prevent short circuit. In recent years, with the development of new energy vehicles and other fields, the capacity and power of lithium ion batteries are increasing, and the safety of lithium ion batteries is receiving more and more attention. The traditional polyolefin diaphragm such as PP and PE has great influence on the safety of the battery due to the defects of lower melting point, poorer thermal dimensional stability, poorer wettability of electrolyte and the like, and becomes a short plate for limiting the development of the power lithium ion battery. Therefore, the novel lithium ion battery diaphragm with high mechanical strength, high temperature resistance and high wettability is particularly important for a high-capacity and high-specific-performance lithium ion battery.
In order to solve the problem, a ceramic coating modified polyolefin composite diaphragm is developed on the basis of a polyolefin diaphragm, namely, inorganic ceramic materials such as alumina, silica and boehmite and other auxiliary agents such as a binder and a solvent are prepared into ceramic slurry, and the ceramic slurry is uniformly coated on one side or two sides of a polyolefin base film by a coating mode such as a tape casting method or a dip coating method. The ceramic coating diaphragm not only has excellent mechanical properties of polyolefin diaphragms, but also has greatly improved properties such as thermal safety, electrolyte wetting and the like, thereby being widely applied. However, the ceramic separator has a problem of large surface density, and inevitably reduces the energy density of the lithium ion battery. In addition, a polyolefin composite diaphragm with a high-temperature-resistant polymer coating is developed, but the coating does not have high mechanical strength, so that the thermal dimensional stability of the composite diaphragm cannot be guaranteed when a polyolefin base film is heated and melted. The polymer nanofiber membrane prepared based on the electrostatic spinning method, such as PAN, PVDF, PI and the like, has the characteristics of high porosity, high liquid absorption, high temperature resistance and the like, and has a great prospect when being used for modifying a polyolefin diaphragm. For example, patent CN104681764A discloses spinning a nanofiber membrane directly on the surface of a ceramic separator to prepare a composite lithium ion battery separator, wherein the nanofiber membrane can reinforce and bound ceramic particles to prevent falling off, and can also be used as a soft buffer layer to improve the contact between the separator and the electrode surface.
SUMMERY OF THE UTILITY MODEL
The utility model provides a lithium ion battery is with multi-functional two-sided heterogeneous Janus diaphragm. The utility model discloses pass through the tie coat with polyolefin single face inorganic coating diaphragm and nanofiber membrane and combine together, can realize multiple functions: the inorganic coating can provide lithium dendrite puncture resistance for the whole composite diaphragm, the nanofiber layer provides high-temperature dimensional stability and high liquid retention, and the polyolefin diaphragm layer can play a hole closing role at high temperature to prevent short circuit inside the battery. The preparation method comprises the specific steps of firstly preparing a high-temperature-resistant polymer nanofiber membrane by an electrostatic spinning method, then compounding the high-temperature-resistant polymer nanofiber membrane on one side of a non-inorganic coating of a commercially available polyolefin single-sided inorganic coating membrane by a gluing process or a rolling process, and finally obtaining the multifunctional double-sided heterogeneous Janus membrane with one surface being an inorganic coating and the other surface being a nanofiber membrane.
A multifunctional double-sided heterogeneous Janus diaphragm for a lithium ion battery is formed by compounding a polyolefin single-sided inorganic coating diaphragm layer, a bonding layer and a high-temperature-resistant polymer nanofiber membrane layer which are sequentially arranged, wherein the bonding layer and the nanofiber membrane layer are positioned on one side of the polyolefin diaphragm, which is not an inorganic coating; the thickness of the polyolefin single-sided inorganic coating diaphragm is 4-25 mu m; the thickness of the high-temperature resistant polymer nanofiber membrane is 0.4-11 mu m; the thickness of the bonding layer is 0.4-4 mu m; the total thickness of the Janus diaphragm is 5-40 mu m.
The polyolefin single-sided inorganic coating diaphragm is one of a polypropylene (PP) single-sided inorganic coating diaphragm, a Polyethylene (PE) single-sided inorganic coating diaphragm and a polypropylene/polyethylene/polypropylene (PP/PE/PP) single-sided inorganic coating diaphragm; the inorganic coating is one of a ceramic coating, boehmite, and a solid electrolyte.
The bonding layer is any one or combination of polyvinyl alcohol, polyethylene glycol, aqueous polyvinylpyrrolidone, carboxymethyl cellulose, PVDF and copolymers thereof.
Wherein the high temperature resistant polymer nanofiber membrane is one or more of aramid fiber, P84, Polyetherimide (PEI), polyvinylidene fluoride (PVDF), Polyacrylonitrile (PAN) and Polyimide (PI).
A multifunctional double-sided heterogeneous Janus membrane comprising the steps of:
a: adding the thermoplastic high-temperature-resistant polymer into an organic solvent for dissolving to obtain a thermoplastic high-temperature-resistant polymer electrostatic spinning solution with the solid content of 3-30%; carrying out solution polycondensation on diamine and dicarboxylic anhydride in an organic solvent to obtain a thermosetting polyimide precursor, namely polyamic acid electrostatic spinning solution with the solid content of 3-30%;
b: b, performing electrostatic spinning on the electrostatic spinning solution obtained in the step A by using an electrostatic spinning machine to obtain a polymer nanofiber membrane, wherein the obtained polyamide acid nanofiber membrane needs to be subjected to heat treatment to obtain a thermosetting polyimide nanofiber membrane;
c: preparing a water-soluble high molecular polymer into a bonding layer solution with the solid content of 0.1-3%;
d: coating the bonding layer solution obtained in the step C on one side of the non-inorganic coating of the polyolefin diaphragm;
e: and D, directly attaching the nanofiber membrane obtained in the step B to the surface of the bonding layer treated in the step D, and drying to obtain the double-sided heterogeneous Janus diaphragm.
Wherein, the organic solvent in the step A is one or more of DMF, DMAC, NMP and DMSO.
Wherein the electrostatic spinning conditions in the step B are as follows: the spinning distance is 3-25cm, preferably 5-20cm, and the spinning voltage is 10-100kV, preferably 15-50 kV; the heat treatment temperature of the polyamic acid nanofiber membrane is 200-400 ℃, and the treatment time is 0.5-2 h.
In the step C, the water-soluble high molecular polymer is any one or combination of polyvinyl alcohol, polyethylene glycol, aqueous polyvinylpyrrolidone and carboxymethyl cellulose.
The coating mode in the step D is any one of spraying, flat plate coating, micro-gravure coating and transfer coating.
In the step E, the drying temperature is 30-90 ℃, preferably 40-80 ℃, and the drying time is 4-15 hours, preferably 5-12 hours. A multifunctional double-sided heterogeneous Janus membrane comprising the steps of:
a: adding the thermoplastic high-temperature-resistant polymer into an organic solvent for dissolving to obtain a thermoplastic high-temperature-resistant polymer electrostatic spinning solution with the solid content of 3-30%; carrying out solution polycondensation on diamine and dicarboxylic anhydride in an organic solvent to obtain a thermosetting polyimide precursor, namely polyamic acid electrostatic spinning solution with the solid content of 3-30%;
b: b, performing electrostatic spinning on the electrostatic spinning solution obtained in the step A by using an electrostatic spinning machine to obtain a polymer nanofiber membrane, wherein the obtained polyamide acid nanofiber membrane needs to be subjected to heat treatment to obtain a thermosetting polyimide nanofiber membrane;
c: adding PVDF and copolymer colloidal particles thereof, a dispersing agent and an aqueous binder into deionized water to obtain colloidal particle coating liquid;
d: uniformly coating the colloidal particle coating solution prepared in the step C on one side of the polyolefin diaphragm non-inorganic coating, and drying;
e: and D, compounding the nanofiber membrane obtained in the step B on the surface of the colloidal particle bonding layer through a rolling process to obtain the double-sided heterogeneous Janus diaphragm.
Wherein, the organic solvent in the step A is one or more of DMF, DMAC, NMP and DMSO.
Wherein the electrostatic spinning conditions in the step B are as follows: the spinning distance is 3-25cm, preferably 5-20cm, and the spinning voltage is 10-100kV, preferably 15-50 kV; the heat treatment temperature of the polyamic acid nanofiber membrane is 200-400 ℃, and the treatment time is 0.5-2 h.
The solid content of the colloidal particle coating liquid in the step C is 3-30%; the dispersing agent is a cellulose derivative, and the binder is an acrylate binder.
The coating mode in the step D is any one of spraying, flat plate coating, micro-gravure coating and transfer coating; the drying temperature is 30-90 ℃, preferably 50-80 ℃, and the drying time is 4-15 hours, preferably 5-12 hours.
In the step E, the rolling process conditions are as follows: the temperature is 40-110 deg.C, preferably 50-100 deg.C, the pressure is 0.1-2.5MPa, preferably 0.2-2MPa, and the time is 5-70s, preferably 10-60 s.
Compared with the prior art, the utility model discloses following good effect has:
1: the utility model provides a pair of lithium ion battery is with multi-functional two-sided heterogeneous Janus diaphragm, the cohesiveness on nanofiber layer and polyolefin layer is strong, is difficult for droing, and is lighter than two-sided inorganic coating diaphragm weight, is favorable to battery energy density's promotion.
2: the utility model provides a pair of lithium ion battery has multiple efficiency with multi-functional two-sided heterogeneous Janus diaphragm: the nanofiber layer has the functions of high-temperature dimensional stability and high liquid retention; the polyolefin diaphragm layer can play a role of closing the pores at high temperature besides the diaphragm function at normal temperature; the inorganic coating may increase the overall lithium dendrite puncture resistance of the separator.
Description of the drawings:
fig. 1 is a schematic structural diagram of a double-sided heterogeneous Janus diaphragm provided in embodiment 1 of the present invention;
fig. 2 is a schematic structural diagram of a double-sided heterogeneous Janus diaphragm provided in embodiment 2 of the present invention;
fig. 3 is a schematic structural diagram of a double-sided heterogeneous Janus diaphragm provided in embodiment 3 of the present invention;
fig. 4 is a schematic structural diagram of a double-sided heterogeneous Janus diaphragm provided in embodiment 4 of the present invention;
fig. 5 is a schematic structural diagram of a double-sided heterogeneous Janus membrane provided in embodiment 5 of the present invention;
fig. 6 is a schematic structural diagram of a double-sided heterogeneous Janus diaphragm provided in embodiment 6 of the present invention;
fig. 7 is a schematic structural diagram of a double-sided heterogeneous Janus diaphragm provided in embodiment 7 of the present invention.
The specific implementation mode is as follows:
the following describes the present invention with reference to specific embodiments. It should be noted that: the following examples are only for illustrating the present invention and are not intended to limit the technical solutions described in the present invention. Thus, although the present invention has been described in detail with reference to the following examples, it will be understood by those skilled in the art that the present invention may be modified and equivalents may be substituted; all such modifications and variations are intended to be included herein within the scope of this disclosure and the present invention and within the scope of the following claims.
Example 1
A double-sided heterogeneous Janus diaphragm is formed by bonding and compounding a polyolefin single-sided inorganic coating diaphragm layer 11 and a high-temperature-resistant polymer nanofiber membrane layer 13 through a bonding layer 12 by using a gluing process. Wherein, the total thickness of the Janus diaphragm is 25.5 μm, the thickness of the polyolefin single-sided inorganic coating diaphragm layer is 15 μm (wherein, the thickness of the polyethylene layer is 12 μm, the thickness of the ceramic coating layer is 3 μm), the thickness of the bonding layer is 0.5 μm, and the thickness of the high-temperature resistant polymer nanofiber membrane layer is 10 μm. The preparation method of the Janus membrane comprises the following steps:
the method comprises the following steps: weighing 10g of PAN powder, adding the PAN powder into 90g of N, N Dimethylformamide (DMF), and stirring at 60 ℃ until PAN is completely dissolved to obtain PAN electrostatic spinning solution with solid content of 10%;
step two: electrospinning the spinning solution through an electrostatic spinning machine to obtain a PAN high-temperature-resistant nanofiber membrane layer, wherein the spinning parameters of the spinning machine are as follows: the spinning distance is 15cm, the spinning voltage is 20kV, and the spinning time is 6 h;
step three: weighing 0.5g of polyvinyl alcohol powder, adding the polyvinyl alcohol powder into 49.5g of deionized water, and stirring at 90 ℃ until the polyvinyl alcohol is completely dissolved to obtain a bonding layer solution with the solid content of 1%;
step four: uniformly coating the bonding layer solution on one side of the non-inorganic coating of the polyolefin diaphragm in a flat plate coating mode;
step five: and directly attaching the PAN nanofiber membrane to the surface of the bonding layer, and placing the PAN nanofiber membrane in an oven at 80 ℃ for 5 hours to obtain the double-sided heterogeneous Janus diaphragm.
Example 2
A double-sided heterogeneous Janus diaphragm is formed by bonding and compounding a polyolefin single-sided inorganic coating diaphragm layer 21 and a high-temperature-resistant polymer nanofiber membrane layer 23 through a bonding layer 22 by using a gluing process. Wherein, the total thickness of the Janus diaphragm is 25.5 μm, the thickness of the polyolefin single-sided inorganic coating diaphragm layer is 15 μm (wherein, the thickness of the polyethylene layer is 12 μm, the thickness of the ceramic coating layer is 3 μm), the thickness of the bonding layer is 0.5 μm, and the thickness of the high-temperature resistant polymer nanofiber membrane layer is 10 μm. The preparation method of the Janus membrane comprises the following steps:
the method comprises the following steps: weighing 15g of P84 resin powder, adding the resin powder into 85g of N, N Dimethylformamide (DMF), and stirring at 60 ℃ until P84 is completely dissolved to obtain a P84 electrostatic spinning solution with the solid content of 15%;
step two: electrospinning the spinning solution by using an electrostatic spinning machine to obtain a P84 high-temperature-resistant nanofiber membrane layer, wherein the spinning parameters of the spinning machine are as follows: the spinning distance is 15cm, the spinning voltage is 30kV, and the spinning time is 6 h;
step three: weighing 0.5g of polyvinyl alcohol powder, adding the polyvinyl alcohol powder into 49.5g of deionized water, and stirring at 90 ℃ until the polyvinyl alcohol is completely dissolved to obtain a bonding layer solution with the solid content of 1%;
step four: uniformly coating the bonding layer solution on one side of the non-inorganic coating of the polyolefin diaphragm in a flat plate coating mode;
step five: and (3) directly attaching the P84 nanofiber membrane to the surface of the bonding layer, and placing the bonding layer in an oven at 80 ℃ for 5 hours to obtain the double-sided heterogeneous Janus diaphragm.
Example 3
A double-sided heterogeneous Janus diaphragm is formed by bonding and compounding a polyolefin single-sided inorganic coating diaphragm layer 31 and a high-temperature-resistant polymer nanofiber membrane layer 33 through a bonding layer 32 by using a gluing process. Wherein, the total thickness of the Janus diaphragm is 25.5 μm, the thickness of the polyolefin single-sided inorganic coating diaphragm layer is 15 μm (wherein, the thickness of the polyethylene layer is 12 μm, the thickness of the ceramic coating layer is 3 μm), the thickness of the bonding layer is 0.5 μm, and the thickness of the high-temperature resistant polymer nanofiber membrane layer is 10 μm. The preparation method of the Janus membrane comprises the following steps:
the method comprises the following steps: weighing 15g of PEI resin particles, adding the PEI resin particles into 85g of N-methylpyrrolidone (NMP), and stirring at 80 ℃ until PEI is completely dissolved to obtain a PEI electrostatic spinning solution with the solid content of 15%;
step two: electrospinning the spinning solution through an electrostatic spinning machine to obtain a PEI high-temperature-resistant nanofiber membrane layer, wherein the spinning parameters of the spinning machine are as follows: the spinning distance is 15cm, the spinning voltage is 25kV, and the spinning time is 6 h;
step three: weighing 0.5g of polyethylene glycol powder, adding the polyethylene glycol powder into 49.5g of deionized water, and stirring at 90 ℃ until polyvinyl alcohol is completely dissolved to obtain a bonding layer solution with the solid content of 1%;
step four: uniformly coating the bonding layer solution on one side of the non-inorganic coating of the polyolefin diaphragm in a flat plate coating mode;
step five: and directly adhering the PEI nanofiber membrane to the surface of the bonding layer, and placing the PEI nanofiber membrane in an oven at 80 ℃ for 5 hours to obtain the double-sided heterogeneous Janus membrane.
Example 4
A double-sided heterogeneous Janus diaphragm is formed by bonding and compounding a polyolefin single-sided inorganic coating diaphragm layer 41 and a high-temperature-resistant polymer nanofiber film layer 43 through a bonding layer 42 by using a rolling process. Wherein, the total thickness of the Janus diaphragm is 21 μm, the thickness of the polyolefin single-sided inorganic coating diaphragm layer is 15 μm (wherein, the thickness of the polyethylene layer is 12 μm, the thickness of the ceramic coating layer is 3 μm), the thickness of the bonding layer is 1 μm, and the thickness of the high-temperature resistant polymer nanofiber film layer is 5 μm. The preparation method of the Janus membrane comprises the following steps:
the method comprises the following steps: weighing 15g of PEI resin particles, adding the PEI resin particles into 85g of N-methylpyrrolidone (NMP), and stirring at 80 ℃ until PEI is completely dissolved to obtain a PEI electrostatic spinning solution with the solid content of 15%;
step two: electrospinning the spinning solution through an electrostatic spinning machine to obtain a PEI high-temperature-resistant nanofiber membrane layer, wherein the spinning parameters of the spinning machine are as follows: the spinning distance is 15cm, the spinning voltage is 30kV, and the spinning time is 6 h;
step three: adding PVDF and copolymer colloidal particles thereof, sodium carboxymethyl cellulose and acrylate emulsion into deionized water to obtain colloidal particle coating liquid with the solid content of 20%;
step four: uniformly coating the colloidal particle coating solution on one side of the polyolefin diaphragm, which is not an inorganic coating, in a flat plate coating mode, and placing the polyolefin diaphragm in a 50 ℃ oven for 5 hours to remove excessive moisture;
step five: and compounding the PEI nanofiber membrane with the colloidal particle layer, and rolling and forming to obtain the double-sided heterogeneous Janus diaphragm, wherein the rolling condition is that the temperature is 50 ℃, the pressure is 0.8MPa, and the time is 100 s.
Example 5
A double-sided heterogeneous Janus diaphragm is formed by bonding and compounding a polyolefin single-sided inorganic coating diaphragm layer 51 and a high-temperature-resistant polymer nanofiber film layer 53 through a bonding layer 52 by using a rolling process. Wherein, the total thickness of the Janus diaphragm is 21 μm, the thickness of the polyolefin single-sided inorganic coating diaphragm layer is 15 μm (wherein, the thickness of the polyethylene layer is 12 μm, the thickness of the ceramic coating layer is 3 μm), the thickness of the bonding layer is 1 μm, and the thickness of the high-temperature resistant polymer nanofiber film layer is 5 μm. The preparation method of the Janus membrane comprises the following steps:
the method comprises the following steps: weighing 15g of P84 resin particles, adding the resin particles into 85g of N, N Dimethylformamide (DMF), and stirring at 60 ℃ until P84 is completely dissolved to obtain a P84 electrostatic spinning solution with the solid content of 15%;
step two: electrospinning the spinning solution by using an electrostatic spinning machine to obtain a P84 high-temperature-resistant nanofiber membrane layer, wherein the spinning parameters of the spinning machine are as follows: the spinning distance is 15cm, the spinning voltage is 25kV, and the spinning time is 6 h;
step three: adding PVDF and copolymer colloidal particles thereof, sodium carboxymethyl cellulose and acrylate emulsion into deionized water to obtain colloidal particle coating liquid with the solid content of 20%;
step four: uniformly coating the colloidal particle coating solution on one side of the polyolefin diaphragm, which is not an inorganic coating, in a flat plate coating mode, and placing the polyolefin diaphragm in a 50 ℃ oven for 5 hours to remove excessive moisture to form a colloidal particle bonding layer;
step five: and compounding the P84 nanofiber membrane with the colloidal particle bonding layer, and rolling and forming to obtain the double-sided heterogeneous Janus diaphragm, wherein the rolling condition is that the temperature is 50 ℃, the pressure is 0.8MPa, and the time is 100 s.
Example 6
A double-sided heterogeneous Janus diaphragm is formed by bonding and compounding a polyolefin single-sided inorganic coating diaphragm layer 61 and a high-temperature-resistant polymer nanofiber film layer 63 through a bonding layer 62 by using a rolling process. Wherein, the total thickness of the Janus diaphragm is 21 μm, the thickness of the polyolefin single-sided inorganic coating diaphragm layer is 15 μm (wherein, the thickness of the polyethylene layer is 12 μm, the thickness of the ceramic coating layer is 3 μm), the thickness of the bonding layer is 1 μm, and the thickness of the high-temperature resistant polymer nanofiber film layer is 5 μm. The preparation method of the Janus membrane comprises the following steps:
the method comprises the following steps: weighing 10g of PAN powder, adding the PAN powder into 90g of N, N Dimethylformamide (DMF), and stirring at 60 ℃ until PAN is completely dissolved to obtain PAN electrostatic spinning solution with solid content of 10%;
step two: electrospinning the spinning solution through an electrostatic spinning machine to obtain a PAN high-temperature-resistant nanofiber membrane layer, wherein the spinning parameters of the spinning machine are as follows: the spinning distance is 15cm, the spinning voltage is 20kV, and the spinning time is 6 h;
step three: adding PVDF and copolymer colloidal particles thereof, sodium carboxymethyl cellulose and acrylate emulsion into deionized water to obtain colloidal particle coating liquid with the solid content of 15%;
step four: uniformly coating the colloidal particle coating solution on one side of the polyolefin diaphragm, which is not an inorganic coating, in a flat plate coating mode, and placing the polyolefin diaphragm in a 50 ℃ oven for 5 hours to remove excessive moisture to form a colloidal particle bonding layer;
step five: and compounding the PAN nanofiber membrane with the colloidal particle bonding layer, and performing roll forming to obtain the double-sided heterogeneous Janus diaphragm, wherein the roll forming condition is that the temperature is 100 ℃, the pressure is 0.6MPa, and the time is 100 s.
Example 7
A double-sided heterogeneous Janus diaphragm is formed by bonding and compounding a polyolefin single-sided inorganic coating diaphragm layer 71 and a high-temperature-resistant polymer nanofiber film layer 73 through a bonding layer 72 by using a rolling process. Wherein, the total thickness of the Janus diaphragm is 21 μm, the thickness of the polyolefin single-sided inorganic coating diaphragm layer is 15 μm (wherein, the thickness of the polyethylene layer is 12 μm, the thickness of the ceramic coating layer is 3 μm), the thickness of the bonding layer is 1 μm, and the thickness of the high-temperature resistant polymer nanofiber film layer is 5 μm. The preparation method of the Janus membrane comprises the following steps:
the method comprises the following steps: 2.016g of pyromellitic dianhydride (PMDA) and 1.850g of 4, 4' -diaminodiphenyl ether (ODA) in a molar ratio of 1:1 are weighed and subjected to solution polycondensation reaction in 30ml of N, N-Dimethylformamide (DMF) to obtain a polyamic acid electrostatic spinning solution with the solid content of 12 percent;
step two: electrospinning the spinning solution by an electrostatic spinning machine to obtain the polyamic acid nanofiber membrane, wherein the spinning parameters of the spinning machine are as follows: the spinning distance is 15cm, the spinning voltage is 20kV, and the spinning time is 6 h; and (3) placing the obtained polyamic acid nanofiber membrane in a 300 ℃ heating furnace for 2h to perform thermal imidization reaction to obtain the thermosetting polyimide nanofiber membrane.
Step three: adding PVDF and copolymer colloidal particles thereof, sodium carboxymethyl cellulose and acrylate emulsion into deionized water to obtain colloidal particle coating liquid with the solid content of 15%;
step four: uniformly coating the colloidal particle coating solution on one side of the polyolefin diaphragm, which is not an inorganic coating, in a flat plate coating mode, and placing the polyolefin diaphragm in a 50 ℃ oven for 5 hours to remove excessive moisture to form a colloidal particle bonding layer;
step five: and compounding the polyimide nanofiber membrane with the colloidal particle bonding layer, and performing roll forming to obtain the double-sided heterogeneous Janus diaphragm, wherein the roll forming condition is that the temperature is 100 ℃, the pressure is 0.6MPa, and the time is 100 s.
Comparative example 1
The adhesive layer in example 7 was removed, and the polyimide nanofiber membrane and the polyolefin separator were directly hot-press molded without changing other conditions to obtain the composite membrane of comparative example 1.
The double-sided heterogeneous Janus diaphragms prepared in examples 1-7 and comparative example 1 and the commercially available 12+2+2 double-sided ceramic coated battery diaphragm serving as comparative example 2 are subjected to performance tests such as porosity, mechanical property, peeling property, thermal dimensional stability and the like, and the lithium iron phosphate serving as a cathode material is adopted to assemble a half-cell to perform electrical performance tests, and the test results are shown in the following table:
TABLE 1 Performance of separator prepared in examples and comparative examples
Figure BDA0002641000600000081
Figure BDA0002641000600000091
TABLE 2 Performance of separator batteries prepared in examples and comparative examples
Figure BDA0002641000600000092
Compared with the prior art, the utility model provides a two-sided heterogeneous Janus diaphragm, for the two-sided ceramic coating battery diaphragm of the present general market 12+2+2 in this field and comparative example, porosity, peel strength, thermal shrinkage all have obvious improvement, do not have obvious influence to tensile strength. In the aspect of electrical property, the cycle life of the rate performance is greatly prolonged.
The above description is only an example of the preferred embodiment of the present invention, and not intended to limit the scope of the present invention, and those skilled in the art should be able to realize the equivalent alternatives and obvious variations of the present invention.

Claims (4)

1. The multifunctional double-sided heterogeneous Janus diaphragm for the lithium ion battery is characterized in that the double-sided heterogeneous Janus diaphragm is formed by compounding a polyolefin single-sided inorganic coating diaphragm layer, a bonding layer and a high-temperature-resistant polymer nanofiber film layer which are sequentially arranged, wherein the bonding layer and the nanofiber film layer are positioned on one side of the polyolefin diaphragm, which is not an inorganic coating; the thickness of the polyolefin single-sided inorganic coating diaphragm is 4-25 mu m; the thickness of the high-temperature resistant polymer nanofiber membrane is 0.4-11 mu m; the thickness of the bonding layer is 0.4-4 μm; the total thickness of the Janus diaphragm is 5-40 mu m.
2. The multifunctional double-sided heterogeneous Janus membrane as claimed in claim 1, wherein the polyolefin single-sided inorganic coating membrane is one of a polypropylene single-sided inorganic coating membrane, a polyethylene single-sided inorganic coating membrane and a polypropylene/polyethylene/polypropylene single-sided inorganic coating membrane, and the inorganic coating is one of a ceramic coating, boehmite and a solid electrolyte.
3. The multifunctional double-sided heterogeneous Janus membrane as claimed in claim 1, wherein the bonding layer is any one or more of polyvinyl alcohol, polyethylene glycol, aqueous polyvinylpyrrolidone, carboxymethyl cellulose, PVDF and copolymers thereof.
4. The multifunctional double-sided heterogeneous Janus membrane as claimed in claim 1, wherein the high temperature resistant polymer nanofiber membrane is any one or combination of aramid, P84, polyetherimide, polyvinylidene fluoride, polyacrylonitrile and polyimide.
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Cited By (1)

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Publication number Priority date Publication date Assignee Title
CN111916622A (en) * 2020-08-19 2020-11-10 北京宇程科技有限公司 Multifunctional double-sided heterogeneous Janus diaphragm for lithium ion battery and preparation method thereof

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN111916622A (en) * 2020-08-19 2020-11-10 北京宇程科技有限公司 Multifunctional double-sided heterogeneous Janus diaphragm for lithium ion battery and preparation method thereof

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