WO2021179740A1

WO2021179740A1 - Diaphragm-negative electrode material of integrated structure and preparation method therefor, and secondary battery

Info

Publication number: WO2021179740A1
Application number: PCT/CN2020/139234
Authority: WO
Inventors: 唐永炳; 李晋; 李翔; 龚德才; 欧学武
Original assignee: 深圳先进技术研究院
Priority date: 2020-03-10
Filing date: 2020-12-25
Publication date: 2021-09-16
Also published as: CN111446422A

Abstract

A diaphragm-negative electrode material of an integrated structure, and a preparation method therefor. The preparation method comprises the following steps: preparing a high-molecular polymer solution and putting same in an injector (2) of an electrostatic spinning apparatus; and placing a metal negative electrode (4) inside the electrostatic spinning apparatus, setting the power source voltage of electrostatic spinning to be 5-30 kV, and the distance between the injector (2) and the metal negative electrode (4) to be 5-50 cm, controlling the flow rate of the high-molecular polymer solution to be 300-1000 μL/h, and preparing a high-molecular diaphragm layer (3) on the surface of the metal negative electrode (4) by means of electrostatic spinning, so as to obtain a diaphragm-negative electrode material of an integrated structure.

Description

Diaphragm negative electrode material of integrated structure, preparation method thereof and secondary battery

Technical field

The present invention relates to the field of lithium ion batteries, and in particular to a diaphragm negative electrode material with an integrated structure, a preparation method thereof, and a secondary battery.

Background technique

As a new type of energy storage device, lithium-ion batteries have the advantages of high energy density, long cycle life, no memory effect, and small self-discharge, and are widely used in various portable mobile devices and electric vehicles. Lithium-ion batteries are mainly composed of positive and negative electrodes, separators, electrolyte and other parts, and are assembled by stacking negative electrodes, separators, and positive electrodes in sequence. When charging, lithium ions are removed from the positive electrode material and migrate to the negative electrode active material; when discharging, lithium ions are removed from the negative electrode active material and return to the positive electrode. Traditional lithium-ion battery negative electrodes usually use graphite as the active material and metal copper foil as the current collector. Recent studies have shown that the use of metal foil as the negative electrode and the integrated design of the negative electrode active material and the negative current collector. This new type of battery system can effectively reduce the weight and volume of the battery, and significantly improve the quality and volume energy density of the battery. .

However, the use of metal foil as a negative electrode has the above advantages, but it also has the following problems: (1) The alloying/dealloying process of the metal negative electrode is likely to cause volume expansion and pulverization; (2) The metal negative electrode is The burrs produced in the process of swelling and pulverization may pierce the separator and cause safety problems; (3) The SEI film formed on the surface of the metal negative electrode is continuously generated-broken-regenerated, consuming a large amount of ions and electrolyte, and causing the coulomb of the battery. low efficiency.

In order to solve the above problems, there are many related solutions, including polymer coating, porous design, high-concentration electrolyte and so on. If there is a research report on a method of polymer coating to improve the performance of aluminum anode. The coated polymer coating inhibits the expansion and pulverization of the aluminum negative electrode during charging and discharging, and at the same time, the coating can effectively isolate the electrolyte and the aluminum negative electrode, and prevent the aluminum negative electrode from being corroded and reacted. This technology ensures the integrity of the aluminum anode structure and alleviates the capacity attenuation caused by the volume expansion and pulverization of the aluminum anode and the continuous regeneration of the unstable SEI film. However, the polymer coating can inhibit the volume expansion and pulverization during the charging and discharging process of the aluminum anode, and effectively isolate the electrolyte from the aluminum anode, and improve the capacity attenuation caused by the continuous regeneration of the SEI film. However, the polymer coating under this technology The combination performance with the metal negative electrode is general, the effect is limited, and the operation process is more complicated. Another example is a three-dimensional porous metal negative electrode, the porous structure of the negative electrode is designed to have high porosity and excellent spatial structure. It is helpful to alleviate the problem of metal negative electrode expansion and powdering caused by stress concentration. At the same time, the structure has a high specific surface area, which can enhance the storage and transport capacity of the electrolyte during the charge and discharge process, facilitate the progress of the electrochemical reaction, and improve the utilization efficiency of the metal negative electrode. However, although the metal anode with a three-dimensional porous structure can play a role in alleviating the volume expansion of the anode during the charge and discharge process, the synthesis and preparation process of this porous structure is more complicated, and the problem of capacity attenuation caused by the continuous regeneration of the SEI film still exists.

For another example, a method for improving the cycle life of a metal negative electrode using a high-concentration electrolyte. In the process of charging and discharging, the high-concentration electrolyte can form a structurally stable SEI film on the surface of the metal negative electrode, thereby improving the service life of the metal negative electrode material and the specific capacity and cycle stability of the new battery. In addition, the use of high-concentration electrolyte can effectively increase the electrochemical window of the electrolyte. However, although the use of high-concentration electrolyte can also improve the cycle stability of the metal negative electrode, the high-concentration electrolyte has insufficient wettability for conventional separator materials, which is not ideal in actual use. Therefore, the current preparation method still cannot completely solve the problems existing in the metal negative electrode.

Summary of the invention

The purpose of the present invention is to provide a separator negative electrode material with an integrated structure, a preparation method thereof, and a secondary battery. Poor battery safety performance and low Coulomb efficiency.

In order to achieve the above-mentioned purpose of the invention, the technical solutions adopted by the present invention are as follows:

A method for preparing a separator anode material with an integrated structure. The preparation method includes the following steps:

Prepare the high molecular polymer solution and place it in the syringe of the electrostatic spinning device;

Place the metal negative electrode in an electrospinning device, set the electrospinning power supply voltage to be 5-30kV, the distance between the syringe and the metal negative electrode is 5-50cm, and control the polymer solution The flow rate is 300-1000 μL/h, and the polymer diaphragm layer is prepared by electrostatic spinning on the surface of the metal negative electrode to obtain the diaphragm negative electrode material of the integrated structure.

And, an integrated structured separator negative electrode material, the integrated structured separator negative electrode material includes a metal negative electrode, and a polymer separator layer bonded on any side of the metal negative electrode.

And, a secondary battery, the secondary battery comprising a positive electrode, an integrated structure of the separator negative electrode material and an electrolyte; wherein the integrated structure of the separator negative electrode material is made of the integrated structure of the separator negative electrode material The preparation method is prepared or obtained by the separator negative electrode material of the integrated structure.

The preparation method of the diaphragm negative electrode material of the integrated structure of the present invention firstly prepares a high molecular polymer solution, adopts the preparation method of electrostatic spinning, and controls the power supply voltage of the electrostatic spinning and the distance between the syringe and the metal negative electrode. And the flow rate of the high molecular polymer solution to prepare the integrated structure of the negative electrode material for the diaphragm. Porosity and controllable porosity can better suppress the volume expansion and pulverization of the negative metal negative electrode during use, and ensure that the metal negative electrode will not form burrs and pierce the separator, ensuring the safety performance of the secondary battery; secondly, through The electrospinning process is combined with the metal negative electrode to form an integrated structure, so that the diaphragm and the metal negative electrode are combined, which further increases the effective contact between the polymer diaphragm layer and the metal negative electrode, and makes the obtained integrated structure The thickness and shape of the structured separator anode material can be designed at will, and the flexibility is good, which to a certain extent inhibits the problem of expansion and pulverization of the metal foil anode during the cycle of the secondary battery, and improves the safety performance and coulomb efficiency of the secondary battery. . The preparation method materials are easily available, the production method is environmentally friendly, and the production process is simple and the conditions are controllable.

According to the integrated structure of the negative electrode material of the separator of the present invention, the negative electrode material of the integrated structure of the separator includes a metal negative electrode, a polymer separator layer bonded to any side of the metal negative electrode, and the separator layer is a polymer separator layer, The polymer separator layer has good flexibility, and has a certain degree of toughness and controllable porosity, which can better inhibit the volume expansion and powdering of the negative metal negative electrode during use, and ensure that the metal negative electrode will not form burrs and thorns. Wear the diaphragm to ensure the safety performance of the secondary battery; and the polymer diaphragm layer is directly combined with the metal negative electrode, which further increases the effective contact between the diaphragm and the metal negative electrode, and makes the thickness of the prepared integrated structure of the diaphragm negative electrode material And the shape can be designed at will, the flexibility is good, to a certain extent, the secondary battery cycle, the metal foil negative electrode is easy to cause the problem of swelling and powdering, and the safety performance and coulomb efficiency of the secondary battery are improved.

In the secondary battery of the present invention, the secondary battery includes a positive electrode, an integrated structured separator negative electrode material and an electrolyte; wherein the integrated structured separator negative electrode material is composed of the integrated structured separator negative electrode material The preparation method is obtained by the preparation method or is the separator negative electrode material with the integrated structure. The use of the above-mentioned integrated structure of the diaphragm negative electrode material or the battery negative electrode prepared by the preparation method of the above-mentioned integrated structure of the diaphragm negative electrode material is used as the negative electrode material of the secondary battery, which simplifies the internal structure and assembly process of the battery, and greatly improves the metal The interface contact characteristics of the negative electrode and the separator, the prepared secondary battery ensures that the metal negative electrode material is not easy to pulverize and can maintain integrity; at the same time, the effective contact distance between the metal negative electrode and the separator is increased, and the cycle stability of the secondary battery is enhanced. Coulomb efficiency.

Description of the drawings

FIG. 1 is a schematic diagram of the structure of a separator negative electrode material with an integrated structure provided by an embodiment of the present invention.

Fig. 2 is an equipment diagram of an electrospinning device provided by an embodiment of the present invention.

FIG. 3 is a schematic structural diagram of a separator negative electrode material with an integrated structure including two polymer separator layers provided by Embodiment 4 of the present invention.

4 is a schematic structural diagram of a separator negative electrode material with an integrated structure including three polymer separator layers provided by Embodiment 5 of the present invention.

Fig. 5 is a schematic structural diagram of a secondary battery provided by an embodiment of the present invention.

Fig. 6 is an electron micrograph of a separator negative electrode material with an integrated structure provided by an embodiment of the present invention.

FIG. 7 is a cross-sectional view of a separator negative electrode material with an integrated structure provided by an embodiment of the present invention.

FIG. 8 is a performance analysis diagram of charging and discharging of the secondary battery provided in Example 1 of the present invention.

Fig. 9 is a performance analysis diagram of the charging and discharging of the secondary battery provided by the comparative example of the present invention.

FIG. 10 is an analysis diagram of the wettability of the separator negative electrode material of the integrated structure provided in the embodiment 1 and the embodiment 2 of the present invention.

Detailed ways

In order to make the objectives, technical solutions and technical effects of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be described clearly and completely below. Obviously, the described embodiments are part of the embodiments of the present invention, not All examples. In combination with the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative work shall fall within the protection scope of the present invention.

In the description of the present invention, it should be understood that the terms "first" and "second" are only used for description purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include one or more of these features. In the description of the present invention, "plurality" means two or more than two, unless otherwise specifically defined.

An example of the present invention provides a separator negative electrode material with an integrated structure. As shown in FIG. Wherein, the polymer diaphragm layer is combined with the metal negative electrode through a spinning process to form an integrated structure.

According to the integrated structure of the negative electrode material of the separator of the present invention, the negative electrode material of the integrated structure of the separator includes a metal negative electrode, a polymer separator layer bonded to any side of the metal negative electrode, and the separator layer is a polymer separator layer, The polymer separator layer has good flexibility, and has a certain degree of toughness and controllable porosity, which can better suppress the volume expansion and pulverization of the negative metal negative electrode during use, and ensure that the metal negative electrode will not form burrs and thorns. Wear the diaphragm to ensure the safety performance of the secondary battery; and the polymer diaphragm layer is directly combined with the metal negative electrode, which further increases the effective contact between the diaphragm and the metal negative electrode, and makes the thickness of the prepared integrated structure of the diaphragm negative electrode material And the shape can be designed at will, the flexibility is good, to a certain extent, the secondary battery cycle, the metal foil negative electrode is easy to cause the problem of swelling and powdering, and the safety performance and coulomb efficiency of the secondary battery are improved.

Preferably, the metal negative electrode is selected from a metal negative electrode in which a negative electrode current collector and a negative electrode material are integrated, and the metal negative electrode is used as a negative electrode current collector and a negative electrode material at the same time, and the negative electrode active material and the current collector are integratedly designed as a new type of battery system , Can effectively reduce the weight and volume of the battery, significantly improve the quality and volume energy density of the battery, and greatly reduce the production cost of the battery.

Preferably, the material of the metal negative electrode is selected from one of aluminum, tin, magnesium, zinc, copper, iron, nickel, titanium, manganese, antimony, bismuth, etc. that undergo alloying battery reactions, or contains at least one of the metals The alloy of the elements. Further preferably, the thickness of the metal negative electrode is 10-1000 μm. In a preferred embodiment of the present invention, the material of the gold substrate is selected from aluminum materials with a thickness of 50 μm.

Preferably, the metal negative electrode is selected from a metal negative electrode that has not undergone pretreatment or a metal negative electrode that has undergone pretreatment. Further preferably, the pretreated metal negative electrode is selected from any one of a polished metal negative electrode, a polished metal negative electrode, a sandblasted metal negative electrode, and a plasma-treated metal negative electrode. Selecting the pretreated metal negative electrode as the negative electrode material can further improve the binding capacity of the metal negative electrode and the polymer separator layer, improve the overall performance of the prepared integrated structure separator negative electrode material, and ensure stronger adhesion. It is not easy to fall off between the metal negative electrode and the polymer separator layer.

Specifically, combined with the polymer separator layer on either side of the metal negative electrode, the polymer separator layer has good flexibility, and has certain toughness and controllable porosity, which can better inhibit the use of the negative metal negative electrode. The problem of medium volume expansion and pulverization ensures that the metal negative electrode will not form burrs and pierce the separator, ensuring the safety performance of the secondary battery.

Preferably, the material of the polymer diaphragm layer is selected from polymethyl methacrylate, tetrahydroperfluorooctyl acrylate, polyvinyl alcohol, polyvinyl phenol, polyvinyl chloride, polyvinyl carbazole, polyvinylidene fluoride At least one of ethylene, polyvinylidene fluoride-hexafluoropropylene, polyacrylonitrile, and polylactic acid. Select high molecular polymers that can exhibit a certain degree of flexibility, toughness and controllable porosity as the raw material of the polymer membrane layer to ensure that the prepared polymer membrane layer has good flexibility, and has certain toughness and flexibility. The controlled porosity can better suppress the volume expansion and pulverization of the negative metal negative electrode during use.

Preferably, the thickness of the polymer membrane layer is 50 μm to 150 μm. If the thickness of the polymer separator layer is too thin, the separator layer is easy to break down or break, thereby affecting the safety performance of the prepared secondary battery; if the thickness of the polymer separator layer is too thick, it will cause The ionic conductivity of the prepared secondary battery will decrease, which affects the performance of the battery.

Preferably, the integrated structure of the separator negative electrode material includes a metal negative electrode, and a polymer separator layer bonded to either side of the metal negative electrode, wherein the polymer separator layer is formed by combining with the metal negative electrode through a spinning process Integrated structure. In a preferred embodiment of the present invention, the spinning process is selected from the electrospinning process.

The separator anode material with the integrated structure provided by the embodiment of the present invention can be prepared by the following method.

Correspondingly, the embodiment of the present invention also provides a method for preparing a separator negative electrode material with an integrated structure. The method includes the following steps:

S01. Prepare a high molecular polymer solution and place it in the syringe of the electrostatic spinning device;

S02. Place the metal negative electrode in the electrospinning device, set the electrospinning power supply voltage to be 5-30kV, the distance between the syringe and the metal negative electrode is 5-50cm, and control the polymer The flow rate of the solution is 300-1000 μL/h, and the polymer diaphragm layer is prepared by electrostatic spinning on the surface of the metal negative electrode to obtain the diaphragm negative electrode material of the integrated structure.

Specifically, in the above step S01, a high-molecular polymer solution is prepared. Preferably, the high-molecular polymer solution includes a high-molecular polymer solute, an additive, and a solvent.

Preferably, the high molecular polymer solution includes a high molecular polymer solute selected from the group consisting of polymethyl methacrylate, tetrahydroperfluorooctyl acrylate, polyvinyl alcohol, polyvinyl phenol, At least one of polyvinyl chloride, polyvinylcarbazole, polyvinylidene fluoride, polyvinylidene fluoride-hexafluoropropylene, polyacrylonitrile, and polylactic acid. Select high molecular polymers that can exhibit a certain degree of flexibility, toughness and controllable porosity as the raw material of the polymer membrane layer to ensure that the prepared polymer membrane layer has good flexibility, and has certain toughness and flexibility. The controlled porosity can better suppress the volume expansion and pulverization of the negative metal negative electrode during use.

Preferably, the high molecular polymer solution includes additives, and the purpose of adding the additives is to enhance the conductivity of the ions and further improve the conductivity of the prepared secondary battery. The additives are selected from Al ₂ O ₃ , SiO ₂ , materials with perovskite configuration ABO ₃ such as Li _0.5 La _0.5 TiO ₃ , materials with LISICON structure such as Li ₁₄ Zn(GeO ₄ ) ₄ , such as Na ₃ Zr ₂ Si ₂ PO ₁₂ NASICON structure material, such as at least one kind of _{Li 7} La ₃ Zr ₂ O _{12 garnet type oxide material.}

Preferably, the high-molecular polymer solution includes a solvent, and the addition of the solvent can better dissolve the high-molecular polymer for preparation of the high-molecular polymer solution. The solvent is selected from at least one of tetrahydrofuran, acetone, dimethylformamide, dimethylacetamide, toluene, water, dichloromethane, and chloroform.

Preferably, the volume percentage concentration of the high molecular polymer solution is 1%-30%. If the concentration of the solution is too low, the adhesion amount of the polymer on the surface of the metal negative electrode will be less. Too little adhesion will affect the flexibility of the polymer diaphragm layer, and also cause the thickness of the prepared polymer diaphragm layer to be too thin , Affect the prepared integrated structure of the separator anode material. If the concentration of the solution is too high, the solubility of the high molecular polymer will be poor, which will easily lead to uneven dissolution of the prepared high molecular polymer solution, which in turn affects the properties of the polymer membrane layer and the integrated structure obtained The separator anode material.

Preferably, the preparation of the high molecular polymer solution includes the following steps: mixing the selected high molecular polymer, additives, and solvent according to the volume percentage concentration of the high molecular polymer solution, and performing the mixing treatment at a temperature between 50 and 80°C to ensure that each The substance dissolves. Further preferably, the time of the mixing treatment is 12 to 48 hours. In a preferred embodiment of the present invention, the mixing treatment method includes, but is not limited to, conventional methods such as stirring.

Further, after the clear high molecular polymer solution is formed, the high molecular polymer solution is placed in the syringe of the electrostatic spinning device for standby.

Specifically, in the above step S02, the metal negative electrode is placed in the electrospinning device, the power supply voltage for electrospinning is set to 5-30kV, and the distance between the syringe and the metal negative electrode is 5-50cm, The flow rate of the high molecular polymer solution is controlled to be 300-1000 μL/h, and a high molecular diaphragm layer is prepared by electrostatic spinning on the surface of the metal negative electrode to obtain the diaphragm negative electrode material of the integrated structure.

Preferably, the material of the metal negative electrode is selected from one of aluminum, tin, magnesium, zinc, copper, iron, nickel, titanium, manganese, antimony, bismuth, etc. that undergo alloying battery reactions, or contains at least one of the metals The alloy of the elements.

Preferably, placing the metal negative electrode in the electrospinning device includes the following steps: cutting the metal negative electrode to obtain an appropriate size, and fixing the metal negative electrode to the collection screen in the electrospinning device. surface.

In a preferred embodiment of the present invention, the electrospinning device is shown in FIG. 2. As shown in FIG. 2, 1 is a high-voltage power supply, 2 is a syringe containing a polymer solution, and 3 is the polymer diaphragm layer. , 4 is the metal negative electrode, and 5 is the receiving screen.

Specifically, the electrospinning power supply voltage is set to 5-30kV, the distance between the syringe and the metal negative electrode is 5-50cm, and the flow rate of the polymer solution is controlled to be 300-1000μL/h. The surface of the metal negative electrode is electrostatically spun to prepare a polymer diaphragm layer to obtain the diaphragm negative electrode material of the integrated structure. In the electrospinning work, the electrospinning power supply voltage, the distance between the syringe and the metal negative electrode, and the flow rate of the polymer solution are important factors that jointly determine whether the spinning solution can be ejected smoothly and reach the collection screen. Therefore, , Limiting the above conditions is conducive to the smooth progress of the test.

Furthermore, the power supply voltage for electrospinning is set to 5-30kV, and the voltage is 5-30kV for the spinning solution to be sprayed smoothly during work. If the power supply voltage is too low, an effective electric field cannot be formed, resulting in the solution not being sprayed. , The product cannot be prepared; if the power supply voltage is too high, it will affect the normal spinning process, and there is a certain degree of danger. Further, the distance between the syringe and the metal negative electrode is 5-50 cm. If the distance between the syringe and the metal negative electrode is too far, it will affect the preparation of the diaphragm layer structure, resulting in the thickness of the diaphragm layer structure being too thin, and thus affecting A membrane negative electrode material with an integrated structure; in a preferred embodiment of the present invention, the distance between the syringe and the metal negative electrode is 10-20 cm. Further, the flow rate of the high-molecular polymer solution is 300-1000 μL/h. If the flow rate of the high-molecular polymer solution is too fast, the uniformity of the spun fiber on the surface of the metal negative electrode will be affected, and the integration will be affected. The performance of the structured diaphragm negative electrode material affects the contact between the polymer diaphragm layer and the metal negative electrode, and cannot well suppress the problem of volume expansion and pulverization of the negative metal negative electrode during use, thereby affecting the safety performance of the secondary battery; If the flow rate of the high molecular polymer solution is too slow, it will affect the continuity of the spinning fiber and cause the high molecular diaphragm layer to be easily broken, and thus it cannot be guaranteed that the metal negative electrode will not form burrs and pierce the diaphragm, affecting the The performance of the separator anode material of the integrated structure leads to the poor safety performance of the secondary battery.

Preferably, the polymer membrane layer is a polymer spinning structure layer or a multi-layer polymer spinning structure layer. Further preferably, the multi-layer polymer spinning structure layer is a multi-layer spinning structure layer of the same polymer material or a multi-layer spinning structure layer of different polymer materials. In some embodiments of the present invention, the integrated structure of the separator negative electrode material includes a metal negative electrode, and a polymer separator layer bonded to any side of the metal negative electrode, wherein the polymer separator layer is a layer of polymer spun Silk structure layer. Combining a polymer spinning structure layer on the surface of the metal negative electrode as a polymer separator layer can better suppress the problem of volume expansion and pulverization of the negative metal negative electrode during use. In some embodiments of the present invention, the membrane negative electrode material of the integrated structure includes a metal negative electrode, and a polymer membrane layer bonded to any side of the metal negative electrode, wherein the polymer membrane layer is a multilayer of the same polymer. Material spinning structure layer. The polymer separator layer is set as a multi-layer spinning structure layer of the same polymer material to form a separator material with higher flexibility, and further suppress the problem of volume expansion and powdering of the metal negative electrode. In some embodiments of the present invention, the integrated structure of the separator negative electrode material includes a metal negative electrode, and a polymer separator layer bonded to any side of the metal negative electrode, wherein the polymer separator layer is a multilayer of different polymers. Material spinning structure layer. The polymer membrane layer is set as a multi-layer spinning structure layer of different polymer materials. According to different needs, different polymer materials are selected to prepare different spinning structure layers, and the formed polymer membrane layer can be different The advantages of polymer spinning are combined to effectively optimize the performance of the integrated structure of the separator anode material, such as adjusting the binding force, wettability, porosity, flexibility and other properties, which is more conducive to a wide range of applications.

Preferably, the method further includes drying the negative electrode material of the separator with the integrated structure under the condition of 30-100°C. More preferably, the dried material is cut into a certain size to prepare an integrated structure of the separator negative electrode material.

Correspondingly, the present invention also provides a secondary battery. The secondary battery includes a positive electrode, an integrated structured separator negative electrode material and an electrolyte; wherein the integrated structured separator negative electrode material is composed of the integrated structure The structured separator negative electrode material is prepared by the preparation method or is the integrated structure separator negative electrode material.

Specifically, as shown in FIG. 5, the secondary battery includes a positive electrode, a separator negative electrode material with an integrated structure, and an electrolyte.

Specifically, the integrated structured separator negative electrode material is the integrated structured separator negative electrode material or is prepared by the integrated structured separator negative electrode material preparation method.

In the integrated structure of the negative electrode material of the separator of the present invention, the negative electrode material of the integrated structure includes a metal negative electrode, and a polymer separator layer bonded to any side of the metal negative electrode. On the one hand, the separator layer is a polymer The diaphragm layer and the polymer diaphragm layer have good flexibility, certain toughness and controllable porosity, which can better suppress the volume expansion and powdering of the negative metal negative electrode during use, and ensure that the metal negative electrode will not form The burr pierces the diaphragm to ensure the safety performance of the secondary battery; on the other hand, the polymer diaphragm layer is combined with the metal negative electrode through a spinning process to form an integrated structure, so that the diaphragm and the metal negative electrode are combined, It further increases the effective contact between the separator and the metal negative electrode, and makes the thickness and shape of the prepared integrated structure of the separator negative electrode material can be designed at will, with good flexibility, and to a certain extent inhibit the metal The foil negative electrode is easy to cause the problem of swelling and pulverization, which improves the safety performance and coulomb efficiency of the secondary battery.

Preferably, the positive electrode is made by coating a positive electrode material on a metal foil current collector. Preferably, the positive electrode material is selected from lithium-containing metal oxides, lithium manganese oxide, lithium cobalt oxide, lithium iron phosphate, ternary materials, natural graphite, activated carbon, carbon nanotubes, graphene, activated carbon fibers, carbon molecular sieves, mesoporous At least one of carbon, carbon foam, and expanded graphite. Preferably, the metal foil current collector is selected from any one of aluminum, tin, magnesium, zinc, copper, iron, nickel, titanium, manganese, antimony, and bismuth, or an alloy containing at least one of the foregoing metal elements. Further preferably, the thickness of the metal foil current collector is 10-1000 μm.

Preferably, the electrolyte level contains a solution of a certain concentration of electrolyte salt. Preferably, the concentration of the electrolyte salt in the electrolyte is 0.1-10 mol/L.

Further preferably, the electrolyte salt is selected from one or more of lithium salt, sodium salt, potassium salt, and calcium salt. In a preferred embodiment of the present invention, the decomposing salt is selected from lithium hexafluorophosphate, potassium hexafluorophosphate, sodium hexafluorophosphate, calcium hexafluorophosphate, lithium tetrafluoroborate, potassium tetrafluoroborate, sodium tetrafluoroborate, lithium fluoride , One or more of lithium perchlorate, lithium oxalate borate, lithium difluorooxalate borate, etc.

Preferably, the solvent of the electrolyte is selected from organic solvents or ionic liquids. Further preferably, the organic solvent is selected from one or more of esters, ethers, sulfones, and nitriles. In some embodiments of the present invention, the organic solvent is selected from propylene carbonate (PC), ethylene carbonate (EC), fluoroethylene carbonate (FEC), dimethyl carbonate (DMC), diethyl carbonate ( DEC), ethyl methyl carbonate (EMC), ethyl acetate (EA), methyl acetate (MA), methyl formate (MF), methyl propionate (MP), ethyl propionate (EP), tetrahydrofuran ( THF), Dimethoxymethane (DMM), 1,3-Dioxolane (DOL), 4-Methyl-1,3-dioxolane (4MeDOL), 1,2-Dimethoxypropane (DMP), dimethyl ether (DME), triethylene glycol dimethyl ether (DG), dimethyl sulfite (DMS), vinyl sulfite (ES), propylene sulfite (PS), two sulfite One or more of ethyl ester (DES), etc. In some embodiments of the present invention, the ionic liquid includes 1-ethyl-3-methylimidazole-hexafluorophosphate, 1-butyl-1-methylpyrrolidine-bistrifluoromethylsulfonimide Salt, 1-ethyl-3-methylimidazole-tetrafluoroborate, 1-butyl-1-methylimidazole-hexafluorophosphate, 1-propyl-3-methylimidazole-hexafluorophosphate , N-methyl, butyl piperidine-bistrifluoromethanesulfonimide salt, N-methyl-N-propylpyrrolidine-bistrifluoromethanesulfonimide salt, 1-propyl-3 -Methylimidazole-bistrifluoromethanesulfonimide salt, 1-propyl-3-methylimidazole-tetrafluoroborate, 1-ethyl-3-methylimidazole-bistrifluoromethanesulfonate Imide salt, 1-butyl-1-methylimidazole-tetrafluoroborate, N-butyl-N-methylpyrrolidine-bistrifluoromethanesulfonimide salt, N-methyl, propyl One or more of piperidine-bistrifluoromethanesulfonimide salt and the like.

Correspondingly, the present invention also provides a method for preparing a secondary battery, which includes the following steps:

G01. Grind the positive electrode active material, binder and conductive carbon black into a slurry according to a certain ratio, and coat it on the metal foil current collector, then dry and cut to obtain the desired size of the positive electrode;

G02. Add a certain electrolyte salt to the corresponding solvent to prepare the electrolyte;

G03. Provide the diaphragm negative electrode material of the integrated structure of the present invention, and cut the diaphragm negative electrode material of the integrated structure to obtain the diaphragm negative electrode material of the integrated structure of a suitable size;

G04. Assemble the positive electrode, the electrolyte, the diaphragm negative electrode material of an integrated structure of suitable size, and other packaging components to obtain the secondary battery.

Charge and discharge the secondary battery prepared by the preparation method of the secondary battery, and set different cycle times of charge and discharge, and further test and analyze the performance of the secondary battery.

Specific examples are further described below.

Example 1

Preparation of diaphragm anode material with integrated structure

According to the volume mass concentration of 10%, dissolve polyacrylonitrile (PAN) in dimethylformamide (DMF), stir it evenly and use it as a high molecular polymer solution. Take 3 ml of the solution and place it in the syringe of the electrospinning device. ；

Provide a metal aluminum foil as a metal negative electrode, cut the metal negative electrode to obtain a material of a suitable size, wipe the surface clean with alcohol, and fix it on the substrate of the electrostatic spinning device;

The electrospinning power supply voltage is set to 15kV, the distance between the syringe and the metal negative electrode is 15cm, and the flow rate of the polymer solution is controlled to 600μL/h. In the integrated structure of the separator negative electrode material, the integrated structure of the separator negative electrode material is a single-layered polymer material with a spinning structure layer.

Dual-ion battery for preparing lithium

A new battery is assembled by using the separator negative electrode material of the integrated structure prepared in the above-mentioned Example 1 through matching with the positive electrode.

Add 0.8g of natural graphite, 0.1g of polyvinylidene fluoride, and 0.1g of conductive carbon black to 2mL of nitrogen-methylpyrrolidone, coat the uniform slurry obtained by grinding on the surface of the carbon-coated aluminum foil, vacuum dry at 80°C for 12 hours, and cut Cut into electrode pieces.

Weigh a certain amount of lithium hexafluorophosphate in the glove box and add it to ethyl methyl carbonate to prepare a 4M lithium hexafluorophosphate electrolyte.

The prepared positive electrode, positive electrode battery case, integrated structure of the separator and negative electrode materials are closely stacked in a certain order, the electrolyte is dripped to completely infiltrate the separator, and finally the assembly of the lithium ion battery is completed by packaging.

Example 2

Preparation of diaphragm anode material with integrated structure

According to the volume mass concentration of 10%, dissolve polyacrylonitrile (PAN) and polyvinylidene fluoride (PVDF) with a volume mass concentration of 7%: 3% in dimethylformamide (DMF), and stir evenly As a high-molecular polymer solution, take 3 ml of the solution and place it in the syringe of the electrospinning device;

Add 0.8g of natural graphite, 0.1g of polyvinylidene fluoride, and 0.1g of conductive carbon black to 2mL of nitrogen-methylpyrrolidone; coat the uniform slurry obtained by grinding on the surface of the carbon-coated copper foil, and vacuum dry at 80°C for 12 hours to obtain the metal For the negative electrode, cut the metal negative electrode to obtain a material of a suitable size, wipe the surface clean with alcohol, and fix it on the substrate of the electrostatic spinning device;

Preparation of lithium-ion batteries

A new battery is assembled by using the integrated structure separator negative electrode material prepared in the above-mentioned Example 2 through matching with the positive electrode.

0.8 g of lithium iron phosphate, 0.1 g of polyvinylidene fluoride, and 0.1 g of conductive carbon black were added to 2 mL of nitrogen-methylpyrrolidone. The uniform slurry obtained by grinding was coated on the surface of the aluminum foil, dried in a vacuum at 80° C. for 12 hours, and cut into electrode sheets as positive electrodes.

Weigh a certain amount of lithium hexafluorophosphate in the glove box, add it to ethylene carbonate (EC), ethyl methyl carbonate (EMC), and dimethyl carbonate (DMC) in a volume ratio of 1:1:1 to form 1M lithium hexafluorophosphate Electrolyte.

The prepared positive electrode and the positive electrode battery case, the integrated structure of the separator and negative electrode materials are closely stacked in a certain order, the electrolyte is dripped to make the separator completely infiltrated, and finally the assembly of the lithium ion battery is completed by packaging.

Example 3

Preparation of diaphragm anode material with integrated structure

Provide a metal tin foil as a metal negative electrode, cut the metal negative electrode to obtain a material of a suitable size, wipe the surface clean with alcohol, and fix it on the substrate of the electrostatic spinning device;

Double ion battery for preparing potassium

Using the integrated structure of the separator negative electrode material prepared in the foregoing Example 3, a new battery can be assembled by matching with the positive electrode.

0.8 g of natural graphite, 0.1 g of polyvinylidene fluoride, and 0.1 g of conductive carbon black were added to 2 mL of nitrogen-methylpyrrolidone. The uniform slurry obtained by grinding was coated on the surface of the carbon-coated aluminum foil, dried in a vacuum at 80° C. for 12 hours, and cut into electrode sheets as the positive electrode.

Weigh a certain amount of potassium hexafluorophosphate in the glove box, add it to ethylene carbonate: dimethyl carbonate (v/v=1:1), and configure it into 0.8M potassium hexafluorophosphate electrolyte.

The prepared positive electrode, the positive electrode battery case, the integrated structure of the separator and the negative electrode material are closely stacked in a certain order, the electrolyte is dripped to make the separator completely infiltrated, and finally the potassium dual-ion battery is assembled by packaging.

Example 4

Preparation of diaphragm anode material with integrated structure

According to the volume mass concentration of 10%, respectively dissolve polyvinyl alcohol (PVA) and polyacrylonitrile (PAN) in dimethylformamide (DMF), stir them evenly, and make polymer solution No. 1 in sequence And high molecular polymer solution No. 2, and take 3 ml of the solution and place it in the syringe of the electrospinning device;

Set the power supply voltage of electrospinning to 15kV, the distance between the syringe and the metal negative electrode is 15cm, and the flow rate of the high molecular polymer solution is controlled to 600 μL/h, first take 3 ml of high molecular polymer solution one No. 2 is prepared. After the preparation is complete, take 3 ml of high molecular polymer solution No. 2 for preparation, and then perform drying treatment, and cut to obtain the diaphragm negative electrode material of the integrated structure, as shown in FIG. 3, wherein the integrated structure The structured separator negative electrode material 3 is composed of two spinning structure layers of different polymer materials, namely a spinning structure layer 3-1 of polyvinyl alcohol material and a spinning structure layer 3-2 of polyacrylonitrile material.

Dual-ion battery for preparing lithium

Using the integrated structure of the separator negative electrode material prepared in the foregoing Example 4, a new battery can be assembled by matching with the positive electrode.

0.8 g of natural graphite, 0.1 g of polyvinylidene fluoride, and 0.1 g of conductive carbon black were added to 2 mL of nitrogen-methylpyrrolidone. The uniform slurry obtained by grinding is coated on the surface of the carbon-coated aluminum foil, dried in a vacuum at 80° C. for 12 hours, and cut into electrode sheets.

Example 5

Preparation of diaphragm anode material with integrated structure

According to the volume mass concentration of 10%, respectively dissolve polyvinyl phenol (PVP), polyvinyl alcohol (PVA), and polyacrylonitrile (PAN) in dimethylformamide (DMF), stir them evenly, and prepare them in sequence. Make high-molecular polymer solution No. 1, high-molecular polymer solution No. 2 and high-molecular polymer solution No. 3. Take 3 ml of the solution and place it in the syringe of the electrostatic spinning device;

Set the power supply voltage of electrospinning to 15kV, the distance between the syringe and the metal negative electrode is 15cm, and the flow rate of the high molecular polymer solution is controlled to 600 μL/h, first take 3 ml of high molecular polymer solution one After the preparation is completed, take 3 ml of high molecular polymer solution No. 2 for preparation, and then take 3 ml of high molecular polymer solution No. 3 for preparation, and then perform drying treatment, and cut to obtain the integrated structure diaphragm The negative electrode material, as shown in Figure 4, wherein the integrated structure of the separator negative electrode material 3 is three layers of spinning structure layers of different polymer materials, namely the polyvinyl phenol material structure layer 3-3, polyvinyl alcohol The spinning structure layer 3-1 of the material and the spinning structure layer 3-2 of the polyacrylonitrile material.

Dual-ion battery for preparing lithium

Using the integrated structure of the separator negative electrode material prepared in the above embodiment 5, a new battery can be assembled by matching with the positive electrode.

Example 6

Compared with Example 1, in the process of preparing an integrated structure of the separator negative electrode material, the volume mass concentration of the polymer solution was changed from "10%" to "5%". All other steps, materials used, and The process parameters are the same, and the diaphragm negative electrode material with the integrated structure is prepared.

Compared with Example 1, in the process of preparing a lithium dual-ion battery, "Using the integrated structure of the separator anode material prepared in Example 1 above, through matching with the positive electrode, assemble a new battery" is modified to "Using the above The membrane negative electrode material of the integrated structure prepared in Example 6 is matched with the positive electrode to assemble a new battery". All other steps, materials used and process parameters are the same to prepare a lithium dual-ion battery.

Example 7

Compared with Example 1, in the process of preparing the membrane negative electrode material of the integrated structure, the volume mass concentration of the polymer solution was changed from "10%" to "6%". All other steps, materials used and The process parameters are the same, and the diaphragm negative electrode material with the integrated structure is prepared.

Compared with Example 1, in the process of preparing a lithium dual-ion battery, "Using the integrated structure of the separator anode material prepared in Example 1 above, through matching with the positive electrode, assemble a new battery" is modified to "Using the above The membrane negative electrode material of the integrated structure prepared in Example 7 is matched with the positive electrode to assemble a new battery". All other steps, materials used and process parameters are the same to prepare a lithium dual-ion battery.

Example 8

Compared with Example 1, in the process of preparing the membrane negative electrode material of the integrated structure, the volume mass concentration of the polymer solution was changed from "10%" to "7%". All other steps, materials used and The process parameters are the same, and the diaphragm negative electrode material with the integrated structure is prepared.

Compared with Example 1, in the process of preparing a lithium dual-ion battery, "Using the integrated structure of the separator anode material prepared in Example 1 above, through matching with the positive electrode, assemble a new battery" is modified to "Using the above The membrane negative electrode material of the integrated structure prepared in Example 8 is matched with the positive electrode to assemble a new battery". All other steps, materials used and process parameters are the same to prepare a lithium dual-ion battery.

Example 9

Compared with Example 1, in the process of preparing the membrane negative electrode material of the integrated structure, the volume mass concentration of the polymer solution was changed from "10%" to "8%". All other steps, materials used and The process parameters are the same, and the diaphragm negative electrode material with the integrated structure is prepared.

Compared with Example 1, in the process of preparing a lithium dual-ion battery, "Using the integrated structure of the separator anode material prepared in Example 1 above, through matching with the positive electrode, assemble a new battery" is modified to "Using the above The membrane negative electrode material of the integrated structure prepared in Example 9 is matched with the positive electrode to assemble a new battery". All other steps, materials used and process parameters are the same to prepare a lithium dual-ion battery.

Example 10

Compared with Example 1, in the process of preparing the membrane negative electrode material of the integrated structure, the volume mass concentration of the polymer solution was changed from "10%" to "9%". All other steps, materials used and The process parameters are the same, and the diaphragm negative electrode material with the integrated structure is prepared.

Compared with Example 1, in the process of preparing a lithium dual-ion battery, "Using the integrated structure of the separator anode material prepared in Example 1 above, through matching with the positive electrode, assemble a new battery" is modified to "Using the above The membrane negative electrode material of the integrated structure prepared in Example 10 is matched with the positive electrode to assemble a new battery". All other steps, materials used, and process parameters are the same to prepare a lithium dual-ion battery.

Example 11

Compared with Example 1, in the process of preparing the membrane negative electrode material of the integrated structure, the volume mass concentration of the polymer solution was changed from "10%" to "11%". All other steps, materials used, and The process parameters are the same, and the diaphragm negative electrode material with the integrated structure is prepared.

Compared with Example 1, in the process of preparing a lithium dual-ion battery, "Using the integrated structure of the separator anode material prepared in Example 1 above, through matching with the positive electrode, assemble a new battery" is modified to "Using the above The membrane negative electrode material of the integrated structure prepared in Example 11 is matched with the positive electrode to assemble a new battery". All other steps, materials used and process parameters are the same to prepare a lithium dual-ion battery.

Example 12

Compared with Example 1, in the process of preparing an integrated structure of the negative electrode material for the separator, the volume mass concentration of the polymer solution was changed from "10%" to "12%". All other steps, materials used, and The process parameters are the same, and the diaphragm negative electrode material with the integrated structure is prepared.

Compared with Example 1, in the process of preparing a lithium dual-ion battery, "Using the integrated structure of the separator anode material prepared in Example 1 above, through matching with the positive electrode, assemble a new battery" is modified to "Using the above The membrane negative electrode material of the integrated structure prepared in Example 12 is matched with the positive electrode to assemble a new battery". All other steps, materials used and process parameters are the same to prepare a lithium dual-ion battery.

Example 13

Compared with Example 1, in the process of preparing the membrane negative electrode material of the integrated structure, the volume mass concentration of the polymer solution was changed from "10%" to "13%". All other steps, materials used and The process parameters are the same, and the diaphragm negative electrode material with the integrated structure is prepared.

Compared with Example 1, in the process of preparing a lithium dual-ion battery, "Using the integrated structure of the separator anode material prepared in Example 1 above, through matching with the positive electrode, assemble a new battery" is modified to "Using the above The membrane negative electrode material of the integrated structure prepared in Example 13 is matched with the positive electrode to assemble a new battery". All other steps, materials used and process parameters are the same to prepare a lithium dual-ion battery.

Example 14

Compared with Example 1, in the process of preparing the membrane negative electrode material of the integrated structure, the volume mass concentration of the polymer solution was changed from "10%" to "14%". All other steps, materials used and The process parameters are the same, and the diaphragm negative electrode material with the integrated structure is prepared.

Compared with Example 1, in the process of preparing a lithium dual-ion battery, "Using the integrated structure of the separator anode material prepared in Example 1 above, through matching with the positive electrode, assemble a new battery" is modified to "Using the above The membrane negative electrode material of the integrated structure prepared in Example 14 is matched with the positive electrode to assemble a new battery". All other steps, materials used and process parameters are the same to prepare a lithium dual-ion battery.

Example 15

Compared with Example 1, in the process of preparing an integrated structure of the separator negative electrode material, the volume mass concentration of the polymer solution was changed from "10%" to "15%", and all other steps, materials used, and The process parameters are the same, and the diaphragm negative electrode material with the integrated structure is prepared.

Compared with Example 1, in the process of preparing a lithium dual-ion battery, "Using the integrated structure of the separator anode material prepared in Example 1 above, through matching with the positive electrode, assemble a new battery" is modified to "Using the above The membrane negative electrode material of the integrated structure prepared in Example 15 is matched with the positive electrode to assemble a new battery". All other steps, materials used and process parameters are the same to prepare a lithium dual-ion battery.

Example 16

Compared with Example 1, the volume mass concentration of the high molecular polymer solution is the same as 10%, and a separate separator material is prepared, and the separator and the negative electrode are not integrated materials.

Compared with Example 1, in the process of preparing a lithium dual-ion battery, a lithium dual-ion battery assembled in the form of a separator and a negative electrode separated is used.

Example 17

Compared with Example 2, in the process of preparing the membrane negative electrode material of the integrated structure, "polyacrylonitrile (PAN) and polyvinylidene fluoride (PVDF) are dissolved in two at a volume mass concentration of 7%: 3%. "Methylformamide (DMF)" is amended to "Dissolve polyacrylonitrile (PAN) and polyvinylidene fluoride (PVDF) with a volume mass concentration of 1%: 9% in dimethylformamide (DMF) ", all other steps, materials used, and process parameters are the same, and the separator negative electrode material with the integrated structure is prepared.

Compared with Example 2, in the process of preparing a lithium ion battery, "Using the integrated structure of the separator negative electrode material prepared in the above Example 2 to assemble a new battery by matching with the positive electrode" is modified to "Using the above embodiment 17. The prepared negative electrode material of the integrated structure of the separator is matched with the positive electrode to assemble a new battery". All other steps, materials used and process parameters are the same to prepare a lithium ion battery.

Example 18

Compared with Example 2, in the process of preparing the membrane negative electrode material of the integrated structure, "polyacrylonitrile (PAN) and polyvinylidene fluoride (PVDF) are dissolved in two at a volume mass concentration of 7%: 3%. "Methylformamide (DMF)" is revised to "Dissolve polyacrylonitrile (PAN) and polyvinylidene fluoride (PVDF) with a volume mass concentration of 2%: 8% in dimethylformamide (DMF) ", all other steps, materials used, and process parameters are the same, and the separator negative electrode material with the integrated structure is prepared.

Compared with Example 2, in the process of preparing a lithium ion battery, "Using the integrated structure of the separator negative electrode material prepared in the above Example 2 to assemble a new battery by matching with the positive electrode" is modified to "Using the above embodiment 18 The prepared negative electrode material of the integrated structure of the separator is matched with the positive electrode to assemble a new battery". All other steps, materials used and process parameters are the same to prepare a lithium ion battery.

Example 19

Compared with Example 2, in the process of preparing the membrane negative electrode material of the integrated structure, "polyacrylonitrile (PAN) and polyvinylidene fluoride (PVDF) are dissolved in two at a volume mass concentration of 7%: 3%. "Methylformamide (DMF)" is amended to "Dissolve polyacrylonitrile (PAN) and polyvinylidene fluoride (PVDF) at a volume mass concentration of 3%: 7% concentration in dimethylformamide (DMF) ", all other steps, materials used, and process parameters are the same, and the separator negative electrode material with the integrated structure is prepared.

Compared with Example 2, in the process of preparing a lithium ion battery, "Using the integrated structure of the separator negative electrode material prepared in the above Example 2 to assemble a new battery by matching with the positive electrode" is modified to "Using the above embodiment 19 The prepared negative electrode material of the integrated structure of the separator is matched with the positive electrode to assemble a new battery". All other steps, materials used and process parameters are the same to prepare a lithium ion battery.

Example 20

Compared with Example 2, in the process of preparing the membrane negative electrode material of the integrated structure, "polyacrylonitrile (PAN) and polyvinylidene fluoride (PVDF) are dissolved in two at a volume mass concentration of 7%: 3%. "Methylformamide (DMF)" is amended to "Dissolve polyacrylonitrile (PAN) and polyvinylidene fluoride (PVDF) at a volume mass concentration of 4%: 6% concentration in dimethylformamide (DMF) ", all other steps, materials used, and process parameters are the same, and the separator negative electrode material with the integrated structure is prepared.

Compared with Example 2, in the process of preparing a lithium ion battery, "Using the integrated structure of the separator negative electrode material prepared in the above Example 2 to assemble a new battery by matching with the positive electrode" is modified to "Using the above embodiment 20. The prepared negative electrode material of the integrated structure of the separator is matched with the positive electrode to assemble a new battery". All other steps, materials used and process parameters are the same to prepare a lithium ion battery.

Example 21

Compared with Example 2, in the process of preparing the membrane negative electrode material of the integrated structure, "polyacrylonitrile (PAN) and polyvinylidene fluoride (PVDF) are dissolved in two at a volume mass concentration of 7%: 3%. "Methylformamide (DMF)" amended to "Dissolve polyacrylonitrile (PAN) and polyvinylidene fluoride (PVDF) at a volume mass concentration of 5%: 5% concentration in dimethylformamide (DMF) ", all other steps, materials used, and process parameters are the same, and the separator negative electrode material with the integrated structure is prepared.

Compared with Example 2, in the process of preparing a lithium ion battery, "Using the integrated structure of the separator negative electrode material prepared in the above Example 2 to assemble a new battery by matching with the positive electrode" is modified to "Using the above embodiment 21. The prepared negative electrode material of the integrated structure of the separator is matched with the positive electrode to assemble a new battery". All other steps, materials used and process parameters are the same to prepare a lithium ion battery.

Example 22

Compared with Example 2, in the process of preparing the membrane negative electrode material of the integrated structure, "polyacrylonitrile (PAN) and polyvinylidene fluoride (PVDF) are dissolved in two at a volume mass concentration of 7%: 3%. "Methylformamide (DMF)" is amended to "Dissolve polyacrylonitrile (PAN) and polyvinylidene fluoride (PVDF) with a volume mass concentration of 6%: 4% in dimethylformamide (DMF) ", all other steps, materials used, and process parameters are the same, and the separator negative electrode material with the integrated structure is prepared.

Compared with Example 2, in the process of preparing a lithium ion battery, "Using the integrated structure of the separator negative electrode material prepared in the above Example 2 to assemble a new battery by matching with the positive electrode" is modified to "Using the above embodiment 22. The prepared negative electrode material of the integrated structure of the separator is matched with the positive electrode to assemble a new battery". All other steps, materials used and process parameters are the same to prepare a lithium ion battery.

Example 23

Compared with Example 2, in the process of preparing the membrane negative electrode material of the integrated structure, "polyacrylonitrile (PAN) and polyvinylidene fluoride (PVDF) are dissolved in two at a volume mass concentration of 7%: 3%. "Methylformamide (DMF)" is amended to "Dissolve polyacrylonitrile (PAN) and polyvinylidene fluoride (PVDF) at a volume mass concentration of 8%: 2% in dimethylformamide (DMF) ", all other steps, materials used, and process parameters are the same, and the separator negative electrode material with the integrated structure is prepared.

Compared with Example 2, in the process of preparing a lithium ion battery, "Using the integrated structure of the separator negative electrode material prepared in the above Example 2 to assemble a new battery by matching with the positive electrode" is modified to "Using the above embodiment 23. The prepared negative electrode material of the integrated structure of the separator is matched with the positive electrode to assemble a new battery". All other steps, materials used and process parameters are the same to prepare a lithium ion battery.

Example 24

Compared with Example 2, in the process of preparing the membrane negative electrode material of the integrated structure, "polyacrylonitrile (PAN) and polyvinylidene fluoride (PVDF) are dissolved in two at a volume mass concentration of 7%: 3%. "Methylformamide (DMF)" is revised to "Dissolve polyacrylonitrile (PAN) and polyvinylidene fluoride (PVDF) with a volume mass concentration of 9%:1% in dimethylformamide (DMF) ", all other steps, materials used, and process parameters are the same, and the separator negative electrode material with the integrated structure is prepared.

Compared with Example 2, in the process of preparing a lithium ion battery, "Using the integrated structure of the separator negative electrode material prepared in the above Example 2 to assemble a new battery by matching with the positive electrode" is modified to "Using the above embodiment 24. The prepared negative electrode material of the integrated structure of the separator is matched with the positive electrode to assemble a new battery". All other steps, materials used and process parameters are the same to prepare a lithium ion battery.

Example 25

Compared with Example 2, "Polyacrylonitrile (PAN) and polyvinylidene fluoride (PVDF) are dissolved in dimethylformamide (DMF) at a concentration of 7% by volume mass concentration: 3%". The preparation Separate separator material, separator and negative electrode are not integrated materials.

Compared with Example 2, in the process of preparing a lithium dual-ion battery, a lithium-ion battery assembled with a separator and a negative electrode separated is used.

Example 26

Compared with Example 3, in the process of preparing the membrane negative electrode material of the integrated structure, the volume mass concentration of the polymer solution was changed from "10%" to "3%". All other steps, materials used and The process parameters are the same, and the diaphragm negative electrode material with the integrated structure is prepared.

Compared with Example 3, in the preparation of a potassium dual-ion battery, "Using the integrated structure of the separator anode material prepared in the above Example 3, through matching with the positive electrode, to assemble a new battery" is modified to "Using the above embodiment 26 The prepared negative electrode material of the integrated structure of the separator is matched with the positive electrode to assemble a new battery. All other steps, materials used and process parameters are the same to prepare a potassium dual-ion battery.

Example 27

Compared with Example 3, in the process of preparing the membrane negative electrode material of the integrated structure, the volume mass concentration of the polymer solution was changed from "10%" to "4%". All other steps, materials used and The process parameters are the same, and the diaphragm negative electrode material with the integrated structure is prepared.

Compared with Example 3, in the preparation of a potassium dual-ion battery, "Using the integrated structure of the separator anode material prepared in the above Example 3, through matching with the positive electrode, to assemble a new battery" is modified to "Using the above embodiment 27. The prepared negative electrode material of the integrated structure of the separator is matched with the positive electrode to assemble a new battery". All other steps, materials used and process parameters are the same to prepare a potassium dual-ion battery.

Example 28

Compared with Example 3, in the process of preparing the membrane negative electrode material of the integrated structure, the volume mass concentration of the polymer solution was changed from "10%" to "5%". All other steps, materials used and The process parameters are the same, and the diaphragm negative electrode material with the integrated structure is prepared.

Compared with Example 3, in the preparation of a potassium dual-ion battery, "Using the integrated structure of the separator anode material prepared in the above Example 3, through matching with the positive electrode, to assemble a new battery" is modified to "Using the above embodiment 28 The prepared negative electrode material of the integrated structure of the separator is matched with the positive electrode to assemble a new battery". All other steps, materials used and process parameters are the same to prepare a potassium dual-ion battery.

Example 29

Compared with Example 3, in the process of preparing the membrane negative electrode material of the integrated structure, the volume mass concentration of the polymer solution was changed from "10%" to "6%". All other steps, materials used and The process parameters are the same, and the diaphragm negative electrode material with the integrated structure is prepared.

Compared with Example 3, in the preparation of a potassium dual-ion battery, "Using the integrated structure of the separator anode material prepared in the above Example 3, through matching with the positive electrode, to assemble a new battery" is modified to "Using the above embodiment 29. The prepared negative electrode material of the integrated structure of the separator is matched with the positive electrode to assemble a new battery". All other steps, materials used and process parameters are the same to prepare a potassium dual-ion battery.

Example 30

Compared with Example 3, in the process of preparing the membrane negative electrode material of the integrated structure, the volume mass concentration of the polymer solution was changed from "10%" to "7%". All other steps, materials used and The process parameters are the same, and the diaphragm negative electrode material with the integrated structure is prepared.

Compared with Example 3, in the preparation of a potassium dual-ion battery, "Using the integrated structure of the separator anode material prepared in the above Example 3, through matching with the positive electrode, to assemble a new battery" is modified to "Using the above embodiment 30 The prepared integrated structure of the separator negative electrode material is matched with the positive electrode to assemble a new battery." All other steps, materials used and process parameters are the same, and a potassium dual-ion battery is prepared.

Example 31

Compared with Example 3, in the process of preparing the membrane negative electrode material of the integrated structure, the volume mass concentration of the polymer solution was changed from "10%" to "8%". All other steps, materials used and The process parameters are the same, and the diaphragm negative electrode material with the integrated structure is prepared.

Compared with Example 3, in the preparation of a potassium dual-ion battery, "Using the integrated structure of the separator anode material prepared in the above Example 3, through matching with the positive electrode, to assemble a new battery" is modified to "Using the above embodiment 31. The prepared integrated structure of the diaphragm negative electrode material is matched with the positive electrode to assemble a new battery." All other steps, materials used and process parameters are the same, and a potassium dual-ion battery is prepared.

Example 32

Compared with Example 3, in the process of preparing the membrane negative electrode material of the integrated structure, the volume mass concentration of the polymer solution was changed from "10%" to "9%". All other steps, materials used and The process parameters are the same, and the diaphragm negative electrode material with the integrated structure is prepared.

Compared with Example 3, in the preparation of a potassium dual-ion battery, "Using the integrated structure of the separator anode material prepared in the above Example 3, through matching with the positive electrode, to assemble a new battery" is modified to "Using the above embodiment 32 The prepared negative electrode material of the integrated structure of the separator is matched with the positive electrode to assemble a new battery". All other steps, materials used and process parameters are the same to prepare a potassium dual-ion battery.

Example 33

Compared with Example 3, in the process of preparing the membrane negative electrode material of the integrated structure, the volume mass concentration of the polymer solution was changed from "10%" to "11%". All other steps, materials used and The process parameters are the same, and the diaphragm negative electrode material with the integrated structure is prepared.

Compared with Example 3, in the preparation of a potassium dual-ion battery, "Using the integrated structure of the separator anode material prepared in the above Example 3, through matching with the positive electrode, to assemble a new battery" is modified to "Using the above embodiment 33. The prepared negative electrode material of the integrated structure of the separator is matched with the positive electrode to assemble a new battery." All other steps, materials used and process parameters are the same to prepare a potassium dual-ion battery.

Example 34

Compared with Example 3, in the process of preparing an integrated structure of the separator negative electrode material, the volume mass concentration of the polymer solution was changed from "10%" to "12%". All other steps, materials used, and The process parameters are the same, and the diaphragm negative electrode material with the integrated structure is prepared.

Compared with Example 3, in the preparation of a potassium dual-ion battery, "Using the integrated structure of the separator anode material prepared in the above Example 3, through matching with the positive electrode, to assemble a new battery" is modified to "Using the above embodiment 34 The prepared negative electrode material of the integrated structure of the diaphragm is matched with the positive electrode to assemble a new battery". All other steps, materials used and process parameters are the same to prepare a potassium dual-ion battery.

Example 35

Compared with Example 3, in the process of preparing the membrane negative electrode material of the integrated structure, the volume mass concentration of the polymer solution is changed from "10%" to "13%". All other steps, materials used and The process parameters are the same, and the diaphragm negative electrode material with the integrated structure is prepared.

Compared with Example 3, in the preparation of a potassium dual-ion battery, "Using the integrated structure of the separator anode material prepared in the above Example 3, through matching with the positive electrode, to assemble a new battery" is modified to "Using the above embodiment 35. The prepared negative electrode material of the integrated structure of the separator is matched with the positive electrode to assemble a new battery". All other steps, materials used and process parameters are the same to prepare a potassium dual-ion battery.

Example 36

Compared with Example 3, in the process of preparing an integrated structure of the negative electrode material for the separator, the volume mass concentration of the polymer solution was changed from "10%" to "14%". All other steps, materials used, and The process parameters are the same, and the diaphragm negative electrode material with the integrated structure is prepared.

Compared with Example 3, in the preparation of a potassium dual-ion battery, "Using the integrated structure of the separator anode material prepared in the above Example 3, through matching with the positive electrode, to assemble a new battery" is modified to "Using the above embodiment 36 The prepared negative electrode material of the integrated structure of the separator is matched with the positive electrode to assemble a new battery". All other steps, materials used and process parameters are the same to prepare a potassium dual-ion battery.

Example 37

Compared with Example 3, in the process of preparing the membrane negative electrode material of the integrated structure, the volume mass concentration of the polymer solution was changed from "10%" to "15%". All other steps, materials used and The process parameters are the same, and the diaphragm negative electrode material with the integrated structure is prepared.

Compared with Example 3, in the preparation of a potassium dual-ion battery, "Using the integrated structure of the separator anode material prepared in the above Example 3, through matching with the positive electrode, to assemble a new battery" is modified to "Using the above embodiment 37 The prepared negative electrode material of the integrated structure of the separator is matched with the positive electrode to assemble a new battery". All other steps, materials used and process parameters are the same to prepare a potassium dual-ion battery.

Example 38

Compared with Example 3, "the volume mass concentration of the polymer solution is 10%" is the same, and a separate separator material is prepared, and the separator and the negative electrode are not an integrated material.

Compared with Example 3, in the process of preparing the potassium dual ion battery, a potassium ion battery assembled in the form of separation of the separator and the negative electrode is used.

Comparative example 1

The secondary battery is prepared by using PP material as the separator, and the separator of the secondary battery is separated from the negative electrode material.

Result analysis

The secondary batteries prepared in the foregoing Examples 1 to 3 were respectively subjected to charge and discharge tests, and analyzed and compared.

The secondary batteries prepared in Example 1, Example 4, Example 5, and Example 6 to Example 16 were respectively subjected to charge and discharge tests, and analyzed and compared. The results are shown in Table 1 below, which can be obtained from Table 1. The secondary battery prepared in Example 1 is a single-layer polymer material spun structure layer integrated structure separator anode material. When the number of cycles is 300, the capacity retention rate is 84%, and the coulombic efficiency is 95%; The secondary battery prepared in Example 4 is an integrated structure of the separator anode material with a double-layer spinning structure layer of different polymer materials. When the number of cycles is 300, the capacity retention rate is 75% , The coulombic efficiency is 90.1%; the secondary battery prepared in Example 5 is an integrated structure of the separator anode material with three layers of different polymer material spinning structure layers. When the number of cycles is 300, the capacity is maintained The rate is 70%, and the Coulomb efficiency is 87.2%. Through the analysis of the secondary batteries prepared in Example 1, Example 4, and Example 5, it can be found that when the integrated structure of the separator anode material is a single-layer polymer material When the spinning structure layer is used, the prepared secondary battery has the highest capacity retention rate and coulombic efficiency, reaching 84% and 95.0%, respectively, which ensures that the prepared secondary battery has better battery performance.

The secondary batteries prepared in Analyzing Example 1, Example 6 to Example 15 can be obtained from Table 1. When preparing an integrated structure of the separator negative electrode material, when the volume of the polyacrylonitrile (PAN) is When the mass concentration increases from 5% to 10%, the capacity retention and coulombic efficiency of the secondary battery prepared accordingly show an upward trend. When the volume mass concentration of the polyacrylonitrile (PAN) increases from 10% to 15% %, the capacity retention and coulombic efficiency of the secondary battery prepared accordingly show a downward trend. When the volume mass concentration of the polyacrylonitrile (PAN) is 10%, the prepared secondary battery (the prepared in Example 1 The capacity retention rate and coulombic efficiency of the secondary battery reached the maximum value, which were 84% and 95%, respectively.

Analyze the secondary batteries prepared in Example 1 and Example 16. Among them, the volume mass concentration of polyacrylonitrile (PAN) used in Example 16 is the same as that in Example 1. The difference is that Example 16 is a diaphragm and The method of separating the negative electrode can be obtained from Table 1. The capacity retention rate and coulombic efficiency of the secondary battery prepared in Example 16 are 60% and 80%, respectively, which are far lower than the capacity of the secondary battery prepared in Example 1. The retention rate and the Coulomb efficiency, therefore, indicate that the use of an integrated structure of the separator anode material can greatly improve the battery charge and discharge performance and safety performance of the secondary battery.

Table 1

The secondary batteries prepared in Example 2 and Example 17 to Example 25 were respectively subjected to charge and discharge tests, and analyzed and compared. The results are shown in Table 2 below. The secondary battery can be obtained from Table 2. For the secondary battery prepared in Example 2, when the number of battery cycles is 200, the capacity retention rate and coulombic efficiency of the secondary battery are 82% and 91.2, respectively %. In the process of preparing an integrated structure of the separator negative electrode material, when the volume mass concentration of the polymer PAN and PVDF changes, the capacity retention rate and coulombic efficiency of the secondary battery prepared accordingly also change. From the concentration ratio of PAN and PVDF from (1%: 9%) to (7%: 3%), the capacity retention rate and coulombic efficiency of the secondary battery prepared accordingly show an upward trend, when the concentration ratio of PAN and PVDF From (7%: 3%) to (9%: 1%), the capacity retention and coulombic efficiency of the secondary battery prepared accordingly show a downward trend, when the concentration ratio of PAN and PVDF is 7%: 3 % The capacity retention rate and coulombic efficiency of the secondary battery prepared in Example 2 (the secondary battery prepared in Example 2) reached the maximum values, which were 82% and 91.2%, respectively.

Analyze the secondary batteries prepared in Example 2 and Example 25. Among them, the concentration ratio of PAN and PVDF used in Example 25 is the same as that in Example 2. The difference is that Example 25 uses a method in which the separator is separated from the negative electrode. As shown in Table 2, the capacity retention rate and coulombic efficiency of the secondary battery prepared in Example 25 are 63% and 76.1%, respectively, which are far lower than the capacity retention rate and coulombic efficiency of the secondary battery prepared in Example 2 Therefore, it shows that the use of an integrated structure of the separator anode material can greatly improve the battery charge and discharge performance and safety performance of the secondary battery.

Table 2

The secondary batteries prepared in Example 3 and Example 26 to Example 38 were respectively subjected to charge and discharge tests, and analyzed and compared. The results are shown in Table 3 below. The results are prepared in Example 3 and Example 26 to Example 37 The secondary battery can be obtained from Table 3. For the secondary battery prepared in Example 3, when the number of cycles of the battery is 300, the capacity retention rate and the coulombic efficiency of the secondary battery are 80% and 81.0, respectively %. In the process of preparing an integrated structure of the separator negative electrode material, when the volume mass concentration of the polymer PAN changes, the capacity retention rate and coulombic efficiency of the secondary battery prepared accordingly also change. When the volume mass concentration of PAN rises from 3% to 10%, the capacity retention and coulombic efficiency of the secondary battery prepared accordingly show an upward trend. When the volume mass concentration of PAN rises from 10% to 15%, the correspondingly prepared The capacity retention rate and coulombic efficiency of the secondary battery show a downward trend. When the volume mass concentration of the PAN is 10%, the capacity retention rate and coulombic efficiency of the secondary battery prepared in Example 3 (the secondary battery prepared in Example 3) reach The maximum values are 80% and 81%, respectively.

Analyze the secondary batteries prepared in Example 3 and Example 38. Among them, the volume mass concentration of PAN used in Example 38 is the same as that in Example 3. The difference is that Example 38 uses a method in which the separator is separated from the negative electrode. From Table 3, the capacity retention rate and coulombic efficiency of the secondary battery prepared in Example 38 are 60% and 70%, respectively, which are far lower than the capacity retention rate and coulombic efficiency of the secondary battery prepared in Example 3 Therefore, it is explained that the use of an integrated structure of the separator negative electrode material can greatly improve the battery charging and discharging performance and safety performance of the secondary battery.

table 3

The integrated structure diaphragm anode material and the secondary battery prepared in Example 1 are further analyzed, and the integrated structure diaphragm anode material prepared in Example 1 is analyzed, and it can be obtained from the electron microscope analysis that the integrated structure The morphology of the polymer spinning structure layer of the separator negative electrode material is shown in Figure 6, and the cross-sectional schematic diagram of the polymer spinning structure layer of the integrated structure separator negative electrode material is shown in Figure 7, from Figures 6 and 7 The morphology of the separator anode material with integrated structure can be clearly analyzed. Further analysis of the charge-discharge cycle stability performance of the secondary battery containing the separator negative electrode material of the integrated structure prepared in Example 1 and the secondary battery whose separator material is a PP separator. It can be seen from Figure 8 that the secondary battery prepared in Example 1, when the number of cycles is 650, the charge and discharge specific capacity of the secondary battery can still maintain 75-80 mAh/g; its coulombic efficiency can also be maintained In 95-96%. It can be seen from Figure 9 that the secondary battery with the separator material made of PP separator, when the number of cycles is 400, the specific capacity of the secondary battery for charging and discharging gradually decreases, only 10-15 mAh/g; its Coulomb efficiency is also Only 80%.

Further compare the wettability of the separator anode material of the integrated structure prepared in Example 1 and Example 2 and the separator of the PP material, as shown in FIG. 10, (a) is the integrated structure of Example 1 The spun separator of the negative electrode material of the separator, (b) is the spun separator of the integrated structure of the negative electrode material of the separator described in Example 2, (c) is the PP separator, which can be judged by the color in Figure 8, (a) And (b) infiltration is more thorough, and the infiltration effect is better than (c).

Therefore, in the integrated structure of the negative electrode material of the separator of the present invention, the negative electrode material of the integrated structure of the separator includes a metal negative electrode, and a polymer separator layer bonded to either side of the metal negative electrode. On the one hand, the separator layer is The polymer membrane layer, the polymer membrane layer has good flexibility, and has a certain degree of toughness and controllable porosity, which can better inhibit the volume expansion and pulverization of the negative metal negative electrode during use, and ensure that the metal negative electrode is not It will form burrs and pierce the diaphragm to ensure the safety performance of the secondary battery; on the other hand, the polymer diaphragm layer is combined with the metal negative electrode through a spinning process to form an integrated structure, so that both the diaphragm and the metal negative electrode are combined. The combination further increases the effective contact between the separator and the metal negative electrode, and the thickness and shape of the prepared integrated structure separator negative electrode material can be designed at will, and the flexibility is good, which to a certain extent prevents the secondary battery from cycling. , The metal foil negative electrode is easy to cause the problem of swelling and pulverization, which improves the safety performance and coulomb efficiency of the secondary battery.

The above descriptions are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modification, equivalent replacement and improvement made within the spirit and principle of the present invention shall be included in the protection of the present invention. Within range.

Claims

A method for preparing a separator negative electrode material with an integrated structure is characterized in that the preparation method includes the following steps:

Prepare the high molecular polymer solution and place it in the syringe of the electrostatic spinning device;

Place the metal negative electrode in an electrospinning device, set the electrospinning power supply voltage to be 5-30kV, the distance between the syringe and the metal negative electrode is 5-50cm, and control the polymer solution The flow rate is 300-1000 μL/h, and the polymer diaphragm layer is prepared by electrostatic spinning on the surface of the metal negative electrode to obtain the diaphragm negative electrode material of the integrated structure.
The method for preparing an integrated structure separator negative electrode material according to claim 1, wherein the polymer separator layer is a layer of a polymer spinning structure layer or a multi-layer polymer spinning structure layer; and/or ,

The metal negative electrode is selected from a metal negative electrode in which a negative electrode current collector and a negative electrode material are integrated.
The method for preparing a separator negative electrode material with an integrated structure according to claim 1, wherein the high molecular polymer solution comprises a high molecular polymer solute, an additive and a solvent; and/or,

The material of the metal negative electrode is selected from one of aluminum, tin, magnesium, zinc, copper, iron, nickel, titanium, manganese, antimony, bismuth, etc. that undergo alloying battery reactions or an alloy containing at least one of the metal elements .
The method for preparing an integrated structured separator negative electrode material according to claim 3, wherein the volume percentage concentration of the high molecular polymer in the high molecular polymer solution is 1%-30%.
The method for preparing an integrated structure separator negative electrode material according to claim 3, wherein the high molecular polymer solute is selected from the group consisting of polymethyl methacrylate, tetrahydroperfluorooctyl acrylate, polyvinyl alcohol, At least one of polyvinylphenol, polyvinyl chloride, polyvinylcarbazole, polyvinylidene fluoride, polyvinylidene fluoride-hexafluoropropylene, polyacrylonitrile, and polylactic acid; and/or,

The additives are selected from Al 2 O 3 , SiO 2 , materials with perovskite configuration ABO 3 such as Li 0.5 La 0.5 TiO 3 , materials with LISICON structure such as Li 14 Zn(GeO 4 ) 4 , such as Na 3 Zr 2 At least one of the NASICON structure material of Si 2 PO 12 , such as the garnet type oxide material of Li 7 La 3 Zr 2 O 12; and/or,

The solvent is selected from at least one of tetrahydrofuran, acetone, dimethylformamide, dimethylacetamide, toluene, water, dichloromethane, and chloroform.
The method for preparing an integrated structured separator negative electrode material according to any one of claims 1 to 5, characterized in that it further comprises drying the obtained integrated structured separator negative electrode material at 30-100°C. Dry treatment.
A diaphragm negative electrode material with an integrated structure is characterized in that the diaphragm negative electrode material with an integrated structure comprises a metal negative electrode and a polymer diaphragm layer combined on any side of the metal negative electrode.
The integrated structure separator anode material according to claim 7, wherein the material of the polymer separator layer is selected from the group consisting of polymethyl methacrylate, tetrahydroperfluorooctyl acrylate, polyvinyl alcohol, polyethylene At least one of base phenol, polyvinyl chloride, polyvinyl carbazole, polyvinylidene fluoride, polyvinylidene fluoride-hexafluoropropylene, polyacrylonitrile, and polylactic acid.
7. The integrated structure separator negative electrode material according to claim 7, wherein the thickness of the polymer separator layer is 50 μm to 150 μm.
A secondary battery, characterized in that the secondary battery comprises a positive electrode, an integrated structure of the diaphragm negative electrode material and an electrolyte; wherein the integrated structure of the diaphragm negative electrode material is composed of any one of claims 1 to 6 The preparation method of the integrated structure of the negative electrode material of the separator is obtained by the preparation method or the negative electrode material of the integrated structure of any one of claims 7-9.