Application of flexible polysulfonamide composite film in preparation of flexible battery current collector

Abstract

The invention relates to the technical field of battery current collector preparation, and discloses application of a flexible polysulfonamide composite film in preparation of a flexible battery current collector, the flexible polysulfonamide composite film reduces the impedance value of the current collector and improves the specific capacity, and the flexible polysulfonamide composite film is formed by compounding polysulfonamide fibers and polysulfonamide fibrids; a plurality of pore channels are distributed between the polysulfonamide fibers and the polysulfonamide fibrids; the pore channels are filled with the whisker carbon nanotubes; the porous film is provided with a plurality of micropores, the micropores penetrate through the film, the micropores are distributed on the surface of the porous film in an array mode, and the micropores are communicated with the pore channels; the micropores and the pore channels which are communicated are used for conveying and accommodating electrolyte and an electrode active material; the content of the whisker carbon nanotubes in the flexible battery current collector is 30-60 wt%; the diameter of the polysulfonamide fiber is 8-12 [mu] m; the flexible polysulfonamide composite film reduces the impedance value of the current collector to 236-281 omega, and the specific capacity of the current collector is increased to 674-980 mAh / g. The flexible battery current collector is low in interface resistance, internal pore channels can adsorb electrolyte and form electron and ion transmission channels, the charging and discharging performance of a lithium battery can be improved, the flexible battery current collector can be folded and bent at will, and the use requirement of portable wearable electronic equipment can be effectively met.

Description

Technical Field

[0001] The present invention relates to the technical field of flexible battery current collector preparation, and in particular to the application of a flexible aromatic sulfone composite film in the preparation of a flexible battery current collector. Background Art

[0002] Lithium-ion batteries have the advantages of high energy, high battery voltage, wide operating temperature range and long storage life, and are widely used in electrical appliances. The lithium-ion batteries currently used are composed of a positive electrode sheet, a separator, a negative electrode sheet and an electrolyte. The positive electrode sheet is composed of a current collector with a positive electrode active material coated on the surface, and the negative electrode sheet is composed of a current collector with a negative electrode active material coated on the surface.

[0003] The function of the current collector is to collect the current generated by the active materials of the battery so as to form a larger current for external output. In existing lithium-ion batteries, metal copper foil or metal aluminum foil is usually used as the current collector. These metal current collectors have high density, poor acid and alkali resistance and high temperature resistance, and low bonding strength between the battery active materials and these metal current collectors, resulting in high interface resistance of the metal current collectors. In addition, the active materials are easy to fall off, and the flexibility is poor. They cannot be bent or squeezed, so they cannot effectively meet the use requirements of portable wearable electronic devices.

[0004] At present, there is a technology that applies aramid paper-carbon nanotubes to lithium-ion batteries, but aramid paper is mainly made by mixing short aramid fibers and precipitated fibers, and then wet-making and hot-pressing. This kind of aramid paper has certain compression resistance, heat resistance, acid and alkali resistance, but it cannot effectively reduce the interface resistance, and the effect is not ideal.

[0005] Therefore, how to effectively reduce the interfacial resistance of the metal current collector and improve the specific capacity is a technical problem that technical personnel in this field urgently need to solve. Summary of the invention

[0006] In view of the above problems, one of the objects of the present invention is to provide a first object is to provide the use of a flexible sulfone composite film in the preparation of a flexible battery current collector. Since the flexible battery current collector can not only be folded and bent at will, but also has a low interface resistance, and the internal pores can also adsorb electrolyte, therefore, the current collector impedance value can be significantly reduced to 236-281Ω; the specific capacity is increased to 674-980mAh / g.

[0007] To achieve this object, the present invention adopts the following technical solutions:

[0008] On the one hand, an embodiment of the present invention provides an application of a flexible sulfone composite film in the preparation of a flexible battery collector, wherein the flexible sulfone composite film reduces the impedance value of the collector, wherein the flexible sulfone composite film is composited by sulfone fibers and sulfone precipitated fibers; a plurality of pores are distributed between the sulfone fibers and the sulfone precipitated fibers; the whisker carbon nanotubes are filled in the pores; the porous film is provided with a plurality of micropores, the micropores penetrate the porous film, a plurality of the micropores are arrayed on the surface of the porous film, and the micropores are connected with the pores; the connected micropores and the pores are used to transport and contain electrolytes and electrode active materials; the content of whisker carbon nanotubes in the flexible battery collector is 30-60wt%; the diameter of the sulfone fibers is 8-12μm; the flexible sulfone composite film reduces the impedance value of the collector to 236-281Ω.

[0009] Furthermore, the weight ratio of the aromatic sulfone fiber to the aromatic sulfone fibril is 1:1.

[0010] Furthermore, the pore size of the micropores is 10-60 μm, and the distance between two micropores is 0.5-5 mm.

[0011] Furthermore, the thickness of the porous film is 0.03-0.08 mm.

[0012] The beneficial effects of the above technical scheme of the present invention are as follows: the flexible battery current collector has a large number of micro-nanoscale channels distributed in the porous film, the surface of the porous film is composed of a multi-microporous structure arranged in an array, and the channels and micropores are interconnected. When a slurry containing an electrode active material is coated on the surface of the flexible battery current collector, the slurry penetrates into the channels inside the porous film through the micropores, so that the electrode active material is firmly combined with the whisker carbon nanotubes in the channels, so that there is no obvious interface between the flexible battery current collector and the electrode active material in the channels, thereby greatly reducing the interface resistance of the flexible battery current collector in operation. These channels can also adsorb electrolytes and form transmission channels for electrons and ions, thereby improving the charging and discharging performance of lithium batteries using the flexible battery current collector. The flexible battery current collector can also be folded and bent at will, thereby effectively meeting the use requirements of portable wearable electronic devices.

[0013] Moreover, the present invention is the first to use the flexible aramid fiber composite film made of aramid fiber and aramid fiber precipitation for flexible battery current collector, which is completely different from the aramid paper in the prior art. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying creative work.

[0015] Figure 1 This is a SEM image of the surface of the flexible battery current collector of the present invention, with a magnification of 2000;

[0016] Figure 2 This is a SEM image of the surface structure of the aromatic sulfone composite film of the present invention, with a magnification of 1000;

[0017] Figure 3 This is a SEM image of the cross section of the aromatic sulfone fiber composite film of the present invention, with a magnification of 5000;

[0018] Figure 4 for Figure 3 A local enlarged view with a magnification of 20,000;

[0019] Figure 5 The SEM image of the surface of the flexible battery current collector of the present invention coated with the positive electrode active material SnO2;

[0020] Figure 6 is a SEM image of a cross section of a flexible battery current collector of the present invention coated with a positive electrode active material SnO2;

[0021] Figure 7 This is an optical photograph of the flexible battery current collector of the present invention;

[0022] Figure 8 The specific capacity cycle stability curve of the lithium battery of the flexible battery current collector of Examples 1, 2 and 3 coated with the positive electrode active material SnO2 of the present invention and the metal copper foil current collector;

[0023] Fig. 9 This is an impedance comparison diagram of lithium batteries using flexible battery current collectors and metal copper foil current collectors according to Examples 1, 2 and 3 of the present invention. DETAILED DESCRIPTION

[0024] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0025] The technical solution of the present invention is further illustrated below through specific implementation methods.

[0026] In the description of this specification, the description with reference to the terms "embodiment", "example", etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0027] Although the embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the claims and their equivalents.

[0028] A flexible battery current collector comprising whisker carbon nanotubes and a porous film;

[0029] The porous film is composited by aramid fiber and aramid fibril; a plurality of pores are distributed between the aramid fiber and the aramid fibril; the whisker carbon nanotubes are filled in the pores; the porous film is provided with a plurality of micropores, the micropores penetrate the porous film, the plurality of micropores are arranged on the surface of the porous film in an array, and the micropores are connected with the pores; the connected micropores and pores are used to transport and contain electrolyte and electrode active materials.

[0030] The flexible battery current collector of the present invention has a large number of micro-nanoscale channels distributed in the porous film. The surface of the porous film is composed of a multi-microporous structure arranged in an array, and the channels are interconnected with the micropores. When a slurry containing an electrode active material is coated on the surface of the flexible battery current collector, the slurry penetrates into the channels inside the porous film through the micropores, so that the electrode active material is firmly combined with the whisker carbon nanotubes in the channels. This makes it so that there is no obvious interface between the flexible battery current collector and the electrode active material in the channels, thereby greatly reducing the interface resistance of the flexible battery current collector in operation. These channels can also adsorb electrolytes and form transmission channels for electrons and ions, thereby improving the charging and discharging performance of lithium batteries using the flexible battery current collector. The flexible battery current collector can also be folded and bent at will, thereby effectively meeting the use requirements of portable wearable electronic devices.

[0031] Specifically, the weight ratio of the aromatic sulfone fiber to the aromatic sulfone fibrid is 1:1.

[0032] The porosity of the porous film formed by the composite of aramid fiber and aramid fiber precipitation fiber in a weight ratio of 1:1 can reach 40-60%.

[0033] Preferably, the diameter of the micropores is 10-60 μm, and the distance between two micropores is 0.5-5 mm.

[0034] The higher the density of the array-like micropores on the surface of the porous film, the more conducive it is for the slurry to penetrate into the pores inside the porous film through the micropores; however, if the number of micropores distributed in the porous film is too large and the spacing is too small, it is easy to cause the porous film to be damaged during use. Therefore, it is more appropriate to limit the pore size of the micropores to 10-60μm and the spacing between two micropores to 0.5-5mm.

[0035] Preferably, the content of whisker carbon nanotubes in the flexible battery current collector is 30-60wt%; and the diameter of the aromatic sulfone fiber is 8-12 μm.

[0036] Aromatic sulfone fibers with a diameter of 8-12 μm have a large surface area.

[0037] After the aramid sulfone fiber is composited with the aramid sulfone fiber, cross-overlapping pores are formed, and 30-60wt% of nano-scale whisker carbon nanotubes are adsorbed in the pores, which can keep the surface resistance of the flexible battery collector below 60.

[0038] Preferably, the thickness of the porous film is 0.03-0.08 mm.

[0039] The total amount of pores in the porous film is positively correlated with the thickness of the porous film. The thickness of the porous film can be configured according to the total mass of whisker carbon nanotubes that need to be filled per unit area of ​​the porous film.

[0040] Furthermore, the present invention provides a method for preparing a flexible battery current collector, which is used to prepare the flexible battery current collector described above, comprising the following steps:

[0041] S1) grinding the whisker carbon nanotubes in a grinder for 12-25 hours, adding deionized water and a dispersant, and mixing them evenly to obtain a carbon fiber slurry;

[0042] S2) mixing the aramid fiber and the aramid fibrid in a weight ratio of 1:1, and pressing the mixture of the aramid fiber and the aramid fibrid into a film using a papermaking device at a feeding rate of 1000-1200 g / min to obtain a porous film;

[0043] S3) placing the carbon fiber slurry in a dispersion tank equipped with a shear disperser and an ultrasonic disperser, and then placing the porous film in the dispersion tank, and in the process of shear dispersion, the carbon fiber slurry is infiltrated into the porous film by the action of ultrasound to obtain an aromatic sulfone film;

[0044] S4) drying the arylsulfone film and then hot pressing to obtain an arylsulfone composite film;

[0045] S5) using a laser drilling device to open a microporous matrix arranged in an array on the surface of the aromatic sulfone composite film, thereby obtaining the flexible battery current collector.

[0046] The preparation method of the flexible battery current collector of the present invention uses a porous film as a carrier, and uses ultrasonic treatment to make whisker carbon nanotubes penetrate and adsorb into the pores in the porous film, and then uses laser drilling equipment to open a microporous matrix arranged in an array in the hot-pressed aromatic sulfone film, so that the flexible battery current collector has channels for transporting and adsorbing electrolytes and electrode active materials, so that the lithium battery equipped with the flexible battery current collector has lower impedance, and thus has better charge and discharge performance than the lithium battery equipped with a copper foil current collector, thereby effectively improving the charge and discharge efficiency of the lithium battery.

[0047] Specifically, in step S1), the carbon fiber slurry is composed of 50-60% whisker carbon nanotubes, 1-3% dispersant and the balance deionized water, calculated by weight percentage; the dispersant is polyvinylidene fluoride.

[0048] The dispersant used is polyvinylidene fluoride, referred to as PVDF. The whisker carbon nanotubes are dispersed in the aqueous solution by the dispersant, which can prevent the whisker carbon nanotubes from agglomerating.

[0049] Preferably, in step S3), the rotation speed of the shearing disperser is 5000 r / min; the frequency of the ultrasonic wave is 80 kHz, and the ultrasonic treatment time is 200 min.

[0050] The whisker carbon nanotubes are uniformly dispersed in the aqueous solution by high-speed shearing at a rotation speed of 5000 r / min, and then the whisker carbon nanotubes are infiltrated into the aromatic sulfone film by ultrasonic treatment.

[0051] Preferably, in step S4), the drying temperature is 60-80° C. and the drying time is 10-15 hours; the hot pressing temperature is 250-300° C. and the hot pressing pressure is 100-180 MPa.

[0052] Drying at 60-80℃ for 10-15 hours allows the aramid film to remain stretched and the moisture on the surface and inside of the aramid film to evaporate completely.

[0053] The sulfone precipitated fibers and the aromatic sulfone fibers are cross-overlapped and bonded together by hot pressing, thereby improving the tensile strength of the porous film.

[0054] Example 1

[0055] The flexible battery current collector of Example 1 was prepared according to the following steps:

[0056] S1) grinding the whisker carbon nanotubes in a grinder for 12 hours, adding deionized water and a dispersant, and mixing them evenly to obtain a carbon fiber slurry;

[0057] S2) mixing the aramid fiber and the aramid fibrid in a weight ratio of 1:1, and pressing the mixture of the aramid fiber and the aramid fibrid into a film using a papermaking device at a feeding rate of 1000-1200 g / min to obtain a porous film;

[0058] S3) placing the carbon fiber slurry in a dispersion tank equipped with a shear disperser and an ultrasonic disperser, and then placing the porous film in the dispersion tank, and in the process of shear dispersion, the carbon fiber slurry is infiltrated into the porous film by the action of ultrasound to obtain an aromatic sulfone film;

[0059] S4) drying the arylsulfone film and then hot pressing to obtain an arylsulfone composite film.

[0060] S5) using a laser drilling device to open a microporous matrix arranged in an array on the surface of the aromatic sulfone composite film, thereby obtaining the flexible battery current collector;

[0061] In step S1), the carbon fiber slurry is composed of 50% whisker carbon nanotubes, 1% dispersant and the balance deionized water, calculated by weight percentage;

[0062] The dispersant is polyvinylidene fluoride;

[0063] The thickness of the porous film obtained in step S2) is 0.06-0.07 mm and the porosity is 40%;

[0064] In step S3), the speed of the shearing disperser is 5000 r / min; the frequency of the ultrasonic wave is 80 kHz, and the ultrasonic treatment time is 200 min;

[0065] In step S4), the drying temperature is 60-70°C for 10 hours; the hot pressing temperature is 250-260°C and the hot pressing pressure is 160-180 MPa;

[0066] In step S5), the pore size of the micropores is 10-15 μm, and the distance between two micropores is 0.5-0.6 mm.

[0067] The content of whisker carbon nanotubes in the flexible battery current collector is 50wt%; the diameter of the aromatic sulfone fiber is 8-12μm.

[0068] The SEM image of the surface of the flexible battery current collector of Example 1 is as follows: Figure 1 As shown, Figure 2 , Figure 3 and Figure 4 Shown are the SEM images of the surface structure of the arylsulfone composite film of Example 1 and the SEM images of the cross section of the arylsulfone composite film of Example 1.

[0069] The SEM image of the surface of the flexible battery current collector of the present invention coated with the positive electrode active material SnO2 is shown in Figure 5 ; The cross-sectional SEM image of the flexible battery current collector of the present invention coated with the positive electrode active material SnO2 is shown Figure 6 ; The optical photograph of the flexible battery current collector of the present invention is shown in Figure 7 .

[0070] Example 2

[0071] The flexible battery current collector of Example 2 was prepared according to the following steps:

[0072] S1) grinding the whisker carbon nanotubes in a grinder for 25 hours, adding deionized water and a dispersant, and mixing them evenly to obtain a carbon fiber slurry;

[0073] S2) mixing the aramid fiber and the aramid fibrid in a weight ratio of 1:1, and pressing the mixture of the aramid fiber and the aramid fibrid into a film using a papermaking device at a feeding rate of 1000-1200 g / min to obtain a porous film;

[0074] S3) placing the carbon fiber slurry in a dispersion tank equipped with a shear disperser and an ultrasonic disperser, and then placing the porous film in the dispersion tank, and in the process of shear dispersion, the carbon fiber slurry is infiltrated into the porous film by the action of ultrasound to obtain an aromatic sulfone film;

[0075] S4) drying the arylsulfone film and then hot pressing to obtain an arylsulfone composite film;

[0076] S5) using a laser drilling device to open a microporous matrix arranged in an array on the surface of the aromatic sulfone composite film, thereby obtaining the flexible battery current collector;

[0077] In step S1), the carbon fiber slurry is composed of 60% whisker carbon nanotubes, 3% dispersant and the balance deionized water, calculated by weight percentage; the dispersant is polyvinylidene fluoride;

[0078] The thickness of the porous film obtained in step S2) is 0.03-0.04 mm, and the porosity is 60%;

[0079] In step S3), the speed of the shearing disperser is 5000 r / min; the frequency of the ultrasonic wave is 80 kHz and the ultrasonic treatment time is 200 min;

[0080] In step S4), the drying temperature is 60-80°C for 15 hours; the hot pressing temperature is 250-300°C and the hot pressing pressure is 100-130MPa;

[0081] In step S5), the pore size of the micropores is 30-35 μm, and the distance between two micropores is 2.5-3.5 mm.

[0082] The content of whisker carbon nanotubes in the flexible battery current collector is 60wt%; the diameter of the aromatic sulfone fiber is 8-12μm.

[0083] Example 3

[0084] The flexible battery current collector of Example 3 was prepared according to the following steps:

[0085] S1) grinding the whisker carbon nanotubes in a grinder for 20 hours, adding deionized water and a dispersant, and mixing them evenly to obtain a carbon fiber slurry;

[0086] S2) mixing the aramid fiber and the aramid fibrid in a weight ratio of 1:1, and pressing the mixture of the aramid fiber and the aramid fibrid into a film using a papermaking device at a feeding rate of 1000-1200 g / min to obtain a porous film;

[0087] S3) placing the carbon fiber slurry in a dispersion tank equipped with a shear disperser and an ultrasonic disperser, and then placing the porous film in the dispersion tank, and in the process of shear dispersion, the carbon fiber slurry is infiltrated into the porous film by the action of ultrasound to obtain an aromatic sulfone film;

[0088] S4) drying the arylsulfone film and then hot pressing to obtain an arylsulfone composite film;

[0089] S5) using a laser drilling device to open a microporous matrix arranged in an array on the surface of the aromatic sulfone composite film, thereby obtaining the flexible battery current collector;

[0090] In step S1), the carbon fiber slurry is composed of 30% whisker carbon nanotubes, 2% dispersant and the balance of deionized water, calculated by weight percentage; the dispersant is polyvinylidene fluoride;

[0091] The thickness of the porous film obtained in step S2) is 0.04-0.05 mm, and the porosity is 50%;

[0092] In step S3), the speed of the shearing disperser is 5000 r / min; the frequency of the ultrasonic wave is 80 kHz, and the ultrasonic treatment time is 200 min;

[0093] In step S4), the drying temperature is 60-70°C for 13 hours; the hot pressing temperature is 260-280°C and the hot pressing pressure is 100-130MPa;

[0094] In step S5), the pore size of the micropores is 55-60 μm, and the distance between two micropores is 4.5-5 mm.

[0095] The content of whisker carbon nanotubes in the flexible battery current collector is 30wt%; the diameter of the aromatic sulfone fiber is 8-12μm.

[0096] Performance Testing

[0097] 1. The surface resistance of the sulfone composite films of Examples 1-3 was tested by a heavy hammer test method using an ACL-800 surface resistance tester. The surface resistances of the sulfone composite films of Examples 1-3 were measured to be 22Ω, 15Ω and 40Ω, respectively.

[0098] 2. The flexible battery current collectors of Example 1, Example 2 and Example 3 were used as positive electrode current collectors, SnO2 was used as positive electrode active material, and lithium sheet was used as negative electrode to prepare lithium ion half-cell 1, lithium ion half-cell 2 and lithium ion half-cell 3; the copper foil was used as positive electrode current collector, SnO2 was used as positive electrode active material, and lithium sheet was used as negative electrode to prepare lithium ion half-cell 4.

[0099] 3. The charge and discharge performance of lithium ion half-cell 1, lithium ion half-cell 2, lithium ion half-cell 3 and lithium ion half-cell 4 were tested according to the following method:

[0100] The charge and discharge performance of the above four lithium-ion half-cells was determined by cyclic voltammetry. Using an AutolabPGSTAT-204 electrochemical workstation, cyclic voltammetry (CV) measurements of the four lithium-ion half-cells were performed in the range of 1.7-2.7V at a scan rate of 0.1mVs-1. The measurement results are shown in Figure 8 .

[0101] 4. The impedance of lithium ion half-cell 1, lithium ion half-cell 2, lithium ion half-cell 3 and lithium ion half-cell 4 was tested as follows: The electrochemical impedance spectroscopy (EIS) of the above lithium ion half-cells was tested using an Autolab PGSTAT-204 electrochemical workstation with a frequency range of 500kHz-0.1Hz and an interference amplitude of 10mV. The measurement results are shown in Fig. 9 .

[0102] According to the above experimental results, the analysis is as follows:

[0103] like Figure 8 As shown, it can be seen that the half-cell using the flexible sulfone composite film of the embodiment of the present invention as the current collector has a significant improvement in specific capacity and cycle stability compared with copper foil. At the same time, with the increase of CNT content in the sulfone composite film, the specific capacity of the lithium battery will gradually increase. After 60 cycles, the specific capacity of Example 2 (60wt% CNT content) can reach 980mAh / g. The specific capacity of Example 1 (50wt% CNT content) can reach 824mAh / g. The specific capacity of Example 3 (30wt% CNT content) can reach 674mAh / g. The specific capacity of copper foil is only 74mAh / g. It can be seen from this that the flexible sulfone composite film current collector of the present invention can significantly improve the specific capacity and cycle stability of lithium batteries.

[0104] Fig. 9 Shown are the electrochemical impedance diagrams of the flexible current collectors and copper foil lithium-ion half-cells of Examples 1, 2, and 3 of the present invention. Under the open circuit voltage state, the charge transfer resistance of the copper foil is the highest, exceeding 600Ω. The current collector impedance value of Example 2 is 236Ω, the current collector impedance value of Example 1 is 267Ω, and the current collector impedance value of Example 3 is 281Ω. It can be seen that the flexible current collector of the embodiment of the present invention can significantly reduce the impedance value of the lithium battery, and as the CNT content in the flexible current collector increases, the impedance value is further reduced. This is mainly because the higher the CNT content, the better the conductivity of the flexible current collector, and at the same time, it will increase the adsorption capacity of the internal pores for the electrolyte, so that the lithium battery has a lower impedance, thereby improving the charge and discharge performance and cycle stability of the lithium battery.

[0105] In summary, the flexible battery current collector has low interfacial resistance, and the internal pores can adsorb electrolyte and form transmission channels for electrons and ions, which can improve the charging and discharging performance of the lithium battery. It can also be folded and bent at will, which can effectively meet the use requirements of portable wearable electronic devices.

[0106] Furthermore, the preparation method of the flexible battery current collector proposed in the present invention uses a porous film as a carrier, and uses ultrasonic treatment to make the whisker carbon nanotubes penetrate and adsorb into the pores in the porous film, and then uses a laser punching device to open an array-arranged microporous matrix in the hot-pressed aromatic sulfone film, so that the flexible battery current collector has channels for transporting and adsorbing electrolytes and electrode active materials, so that the lithium battery equipped with the flexible battery current collector has lower impedance, and thus has better charge and discharge performance than the lithium battery equipped with a copper foil current collector, thereby effectively improving the charge and discharge efficiency of the lithium battery.

[0107] The various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the various embodiments can be referenced to each other.

[0108] The above description of the disclosed embodiments enables one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. Application of flexible arylsulfone composite film in the preparation of flexible battery current collector, characterized in that: The flexible sulfone composite film reduces the current collector impedance value and improves the specific capacity, wherein the flexible sulfone composite film is composited by sulfone fibers and sulfone precipitated fibers; a plurality of pores are distributed between the sulfone fibers and the sulfone precipitated fibers; the whisker carbon nanotubes are filled in the pores; the porous film is provided with a plurality of micropores, the micropores penetrate the porous film, a plurality of the micropores are arrayed on the surface of the porous film, and the micropores are connected with the pores; the connected micropores and the pores are used to transport and contain electrolyte and electrode active materials; the content of whisker carbon nanotubes in the flexible battery current collector is 30-60wt%; the diameter of the sulfone fibers is 8-12μm; the flexible sulfone composite film reduces the current collector impedance value to 236-281Ω, and the specific capacity is increased to 674-980mAh / g.

2. The use according to claim 1, characterized in that: The weight ratio of the aramidsulfone fiber to the aramidsulfone fibrid is 1:

1.

3. The use according to claim 1, characterized in that: The pore size of the micropores is 10-60 μm, and the distance between two micropores is 0.5-5 mm.

4. The use according to claim 1, characterized in that: The thickness of the porous film is 0.03-0.08 mm.

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