Electrode, preparation method therefor, and use thereof

Abstract

Provided in the present application are an electrode, a preparation method therefor, and the use thereof. The electrode comprises a current collector, a fibrous network layer and an active material layer that are stacked. The fibrous network layer is disposed between the current collector and the active material layer; the fibrous network layer comprises conductive polymer fibers, and the conductive polymer fibers are interwoven into a network structure. The electrode provided in the present application is provided with the fibrous network layer disposed between the current collector and the active material layer, and the fibrous network layer has conductive polymer fibers with good conductivity, thus helping to improve the bonding strength between the active material layer and the current collector, and improve the conductivity and cycle stability.

Description

Electrode, preparation method and application thereof

[0001] Cross-reference to related applications

[0002] The present application claims priority from the Chinese patent application No. 2024108693971 filed on June 29, 2024, and entitled "Electrode, preparation method and application thereof", the content of which is incorporated herein by reference in its entirety. TECHNICAL FIELD

[0003] The present application relates to the field of battery, in particular to an electrode, a preparation method and application thereof. BACKGROUND

[0004] At present, the electrode includes a current collector and an active material layer arranged on the surface of the current collector. During the charging and discharging process of the battery, the active material layer may fall off, which reduces the service life and stability of the battery. In the related art, a binder can be added to the active material layer to improve the binding capacity of the active material layer and the current collector. However, too much binder will reduce the conductivity of the electrode and the capacity of the battery, which is not conducive to improving the electrochemical performance of the battery. Therefore, there is a need for an electrode with good binding force between the active material layer and the current collector, high conductivity and good cycle stability.

[0005] SUMMARY

[0006] In view of this, the present application provides an electrode, a preparation method and application thereof. The electrode has a fiber network layer between the current collector and the active material layer, which includes conductive polymer fibers with good conductivity. The fiber network layer can improve the binding force between the current collector and the active material layer, and improve the conductivity and cycle stability of the electrode.

[0007] In a first aspect, the present application provides an electrode, which includes a current collector, a fiber network layer and an active material layer arranged in layers. The fiber network layer is arranged between the current collector and the active material layer. The fiber network layer includes conductive polymer fibers, which are interwoven into a network structure.

[0008] Optionally, the conductivity of the conductive polymer fibers is 50 S / cm-500 S / cm.

[0009] Optionally, the conductive polymer fibers include one or more of polyaniline fibers, polypyrrole fibers and polythiophene fibers.

[0010] Optionally, the diameter of the conductive polymer fibers is 10 nm-200 nm.

[0011] Optionally, the porosity of the fiber network layer is 40%-75%.

[0012] Optionally, the average pore size of the fiber network layer is 1-30 microns.

[0013] Optionally, the conductive polymer fibers are interwoven into a three-dimensional network structure.

[0014] Optionally, the active material layer comprises an active material, and the fiber network layer is distributed with the active material on one side close to the active material layer.

[0015] Optionally, in the fiber network layer, the depth of distribution of the active material is 100 nm-1.8 microns.

[0016] Optionally, the active material layer comprises an active material, and the active material is a positive electrode active material or a negative electrode active material.

[0017] Optionally, the positive electrode active material comprises one or more of lithium cobalt oxide material, nickel cobalt manganese ternary material, nickel cobalt aluminum ternary material, lithium nickel cobalt manganese aluminum oxide, lithium iron phosphate material, lithium manganese phosphate material, lithium vanadium phosphate material, lithium manganate material, and lithium-rich manganese-based material.

[0018] Optionally, the negative electrode active material comprises one or more of artificial graphite, natural graphite, hard carbon, soft carbon, and graphene.

[0019] The electrode provided by the present application has a fiber network layer with good conductivity, which is conducive to improving the bonding force, electrical conductivity, and cycle performance of the electrode.

[0020] In a second aspect, the present application provides a method for preparing an electrode, comprising:

[0021] forming the fiber network layer on the surface of the current collector;

[0022] placing an active material on the surface of the fiber network layer to obtain the electrode.

[0023] Optionally, the conductive polymer solution is used to form the fiber network layer on the surface of the current collector by electrospinning, melt spinning, solution spinning, gel spinning, or template method.

[0024] Optionally, the conductive polymer solution comprises a conductive polymer, and the conductive polymer comprises one or more of conductive polyaniline, conductive polypyrrole, and conductive polythiophene.

[0025] Optionally, in the conductive polymer solution, the mass percentage of the conductive polymer is 2-10%.

[0026] Optionally, the conductive polymer solution further comprises a solvent.

[0027] Optionally, the solvent comprises one or more of concentrated sulfuric acid, N,N-dimethylformamide, N-methylpyrrolidone and methyl chloride.

[0028] Optionally, the preparation method further comprises, after the active material is arranged on the surface of the fiber network layer, rolling the active material.

[0029] Optionally, the temperature of the rolling is 60-90℃.

[0030] The preparation method of the electrode provided by the application is novel, the preparation process is simple, the electrode active material layer and the current collector prepared by the method have good binding force, good electrical conductivity and excellent cycle performance.

[0031] In a third aspect, the application provides a battery, which comprises a positive electrode and a negative electrode, and a separator arranged between the positive electrode and the negative electrode, wherein the negative electrode and / or the positive electrode comprises the electrode of the first aspect or the electrode prepared by the preparation method of the second aspect.

[0032] The battery provided by the application has excellent electrochemical performance and long service life.

[0033] In a fourth aspect, the application provides an electrical equipment, which comprises the battery of the third aspect.

[0034] The electrical equipment provided by the application has excellent comprehensive performance, greatly improved safety performance and strong product competitiveness. BRIEF DESCRIPTION OF DRAWINGS

[0035] In order to more clearly illustrate the technical solutions in the embodiments of the application or the prior art, the drawings needed to be used in the embodiments or the prior art description will be briefly introduced. The specific embodiments described herein are only used to explain the application, and are not used to limit the application.

[0036] Fig. 1 is a schematic view of the cross-sectional structure of the electrode provided by an embodiment of the application;

[0037] Fig. 2 is a flowchart of the preparation method provided by an embodiment of the application. DETAILED DESCRIPTION

[0038] The technical solutions in the embodiments of the application will be described clearly and completely below with reference to the drawings in the embodiments of the application. Obviously, the described embodiments are only some of the embodiments of the application, but not all the embodiments of the application. Based on the embodiments in the application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the application.

[0039] Referring to FIG. 1, a cross-sectional structure of an electrode provided in an embodiment of the present application is shown. The electrode 100 includes a current collector 11, a fiber network layer 12 and an active material layer 13 arranged in layers. The fiber network layer 12 is arranged between the current collector 11 and the active material layer 13. The fiber network layer 12 includes conductive polymer fibers which are interwoven into a network structure. In the present application, the fiber network layer arranged between the active material layer and the current collector can improve the binding ability between the active material layer and the current collector, preventing the active material layer from peeling off during use of the battery. The conductive polymer fibers in the fiber network layer have high tensile strength and excellent conductivity, which can improve the flexibility and electrical conductivity of the electrode, reduce the impedance of the electrode, and help improve the cycle stability and electrochemical performance of the electrode. The conductive polymer fibers have a filamentous structure. The fiber network layer 12 includes a plurality of conductive polymer fibers which are interwoven and entangled with each other, and the plurality of conductive polymer fibers are interwoven to form a network structure, which can improve the binding force between the current collector and the active material layer. The electrode provided in the present application has strong binding force between the active material layer and the current collector, high electrical conductivity and good cycle stability, which helps improve the electrochemical performance and service life of the battery.

[0040] In the present application, the current collector converts chemical energy into electrical energy for output, improving the electrical conductivity of the electrode. The current collector is a positive electrode current collector or a negative electrode current collector. When the electrode is a positive electrode, the current collector is a positive electrode current collector. When the electrode is a negative electrode, the current collector is a negative electrode current collector. In an embodiment of the present application, the positive electrode current collector can be, but is not limited to, one or more of copper, aluminum, nickel and stainless steel. The negative electrode current collector can include, but is not limited to, one or more of copper, aluminum, nickel and stainless steel. In an embodiment of the present application, when the current collector is a positive electrode current collector, the electrode is a positive electrode, and the current collector can be an aluminum foil. In another embodiment of the present application, when the current collector is a negative electrode current collector, the electrode is a negative electrode, and the current collector can be a copper foil.

[0041] In the present application, the active material in the active material layer 13 is a positive electrode active material or a negative electrode active material. When the electrode is a positive electrode, the active material layer 13 is a positive electrode active material layer, and the active material in the active material layer 13 is a positive electrode active material. When the electrode is a negative electrode, the active material layer 13 is a negative electrode active material layer, and the active material in the active material layer 13 is a negative electrode active material. In an embodiment of the present application, the positive electrode active material can include, but is not limited to, one or more of doped or undoped lithium cobaltate material, nickel-cobalt-manganese ternary material, nickel-cobalt-aluminum ternary material, lithium nickel cobalt manganese aluminum oxide, lithium iron phosphate material, lithium manganese phosphate material, lithium vanadium phosphate material, lithium manganese oxide material, and lithium-rich manganese-based material. The negative electrode active material can include, but is not limited to, one or more of artificial graphite, natural graphite, hard carbon, soft carbon, and graphene. In an embodiment of the present application, when the active material is a positive electrode active material, the active material can be a lithium iron phosphate material. In another embodiment of the present application, when the active material is a negative electrode active material, the active material can be artificial graphite.

[0042] In an embodiment of the present application, the active material layer further includes a conductive agent and a binder. The conductive agent can improve the conductivity of the electrode, and the binder can improve the binding ability between the components of the active material layer and between the active material layer and the current collector, thereby improving the mechanical properties of the electrode.

[0043] In an embodiment of the present application, the conductive agent can include, but is not limited to, one or more of carbon nanotubes, acetylene black, graphene, conductive graphite, and carbon black. In an embodiment of the present application, the conductive agent is conductive graphite. In another embodiment of the present application, the conductive agent can be carbon nanotubes.

[0044] In an embodiment of the present application, the binder can include, but is not limited to, one or more of polyvinylidene fluoride, polyvinylidene fluoride, polytetrafluoroethylene, polyethylene, polypropylene, polystyrene, polybutadiene, acrylic resin, epoxy resin, polyethylene oxide, sodium carboxymethyl cellulose, and butadiene-styrene latex. In an embodiment of the present application, the binder is polyvinylidene fluoride. In another embodiment of the present application, the binder is polytetrafluoroethylene.

[0045] In the present application, the fiber network layer 12 is arranged between the current collector 11 and the active material layer 13. Through mechanical interlocking, the binding ability between the current collector 11 and the active material layer 13 can be improved, the peeling strength and mechanical strength of the electrode can be improved, and the peeling of the active material layer 13 can be prevented. The fiber network layer 12 includes a plurality of conductive polymer fibers interwoven and wound with each other. The conductive polymer fibers have good conductive performance, can reduce the contact resistance between the current collector 11 and the active material layer 13, improve the kinetic performance of the electrode tab, improve the conductive ability of the fiber network layer 12, and be beneficial to improve the electrical conductivity of the electrode 100. At the same time, the fiber structure has high tensile strength, which can improve the flexibility of the electrode.

[0046] In an embodiment of the present application, the conductive polymer fiber is in a filamentous structure, and the fiber network layer 12 comprises a plurality of conductive polymer fibers interwoven with each other, the plurality of conductive polymer fibers being interwoven to form a network structure, which can enhance the binding force between the current collector and the active material layer; the conductive polymer fiber has a conductive ability, a high electrical conductivity, and can reduce the impedance of the electrode; the conductive polymer fiber has excellent tensile strength, and can improve the flexibility of the electrode. Specifically, the conductive polymer fiber can include, but is not limited to, one or more of polyaniline fiber, polypyrrole fiber and polythiophene fiber. In an embodiment of the present application, the conductive polymer fiber includes polyaniline fiber. In another embodiment of the present application, the conductive polymer fiber includes polypyrrole fiber.

[0047] In an embodiment of the present application, the conductive polymer fiber has an electrical conductivity of 50 S / cm-500 S / cm, which is conducive to improving the electrical conductivity of the electrode. Specifically, the electrical conductivity of the conductive polymer fiber can be, but is not limited to, 50 S / cm, 100 S / cm, 200 S / cm, 300 S / cm, 400 S / cm or 500 S / cm, etc. In an embodiment of the present application, the electrical conductivity of the conductive polymer fiber can be 50 S / cm-300 S / cm. In another embodiment of the present application, the electrical conductivity of the conductive polymer fiber can be 250 S / cm-500 S / cm.

[0048] In an embodiment of the present application, the conductive polymer fiber has a diameter of 10 nm-200 nm, and the fiber surface at the nanometer level has a high energy, which can be embedded into the active material layer to improve the binding force between the active material layer and the current collector. Through the mechanical interlocking effect of the nanometer structure of the conductive polymer fiber, the additional adhesion between the current collector and the active material layer can be improved, the peeling strength and the mechanical strength of the electrode can be improved, and the active material layer can be prevented from falling off during the charging and discharging process. Specifically, the diameter of the conductive polymer fiber can be, but is not limited to, 10 nm, 50 nm, 80 nm, 100 nm, 120 nm, 140 nm, 160 nm, 180 nm or 200 nm. In an embodiment of the present application, the diameter of the conductive polymer fiber can be 20 nm-100 nm, which is conducive to further improving the binding force and the electrical conductivity of the electrode.

[0049] In an embodiment of the present application, the porosity of the fiber network layer 12 is 40%-75%, the fiber network layer has a large number of pores, forms a network structure, can relieve stress and strain generated during charging and discharging, and improve the service life of the electrode; can promote the ion and / or electron transmission rate, and improve the conductivity of the fiber network layer. Specifically, the porosity of the fiber network layer can be, but is not limited to, 40%, 45%, 50%, 55%, 60%, 65%, 70%, or 75%, etc. In an embodiment of the present application, the porosity of the fiber network layer can be 45%-70%, which can further relieve stress and strain during charging and discharging, and is beneficial to improve the service life of the electrode.

[0050] In an embodiment of the present application, the average pore size of the fiber network layer 12 is 1 μm-30 μm, and the appropriate average pore size can improve the mechanical properties of the electrode and the electrical conductivity between the active material layer and the current collector. Specifically, the average pore size of the fiber network layer can be, but is not limited to, 1 μm, 5 μm, 10 μm, 15 μm, 20 μm, 25 μm, or 30 μm, etc. In an embodiment of the present application, the average pore size of the fiber network layer can be 5 μm-20 μm, which can further improve the mechanical properties of the electrode.

[0051] In an embodiment of the present application, the fiber network layer 12 has active material distributed on the side close to the active material layer 13. The fiber network layer 12 has a certain porosity, and part of the active material in the electrode is filled in the pores of the fiber network layer, which improves the bonding force between the fiber network layer and the active material layer, and further improves the bonding ability between the active material layer and the current collector, and improves the structural stability of the electrode.

[0052] In an embodiment of the present application, in the fiber network layer, the distribution depth of the active material is 100 nm-1.8 μm, which improves the bonding force between the fiber network layer and the active material layer, and further improves the bonding ability between the active material layer and the current collector, and improves the structural stability of the electrode. Specifically, in the fiber network layer, the distribution depth of the active material can be, but is not limited to, 100 nm, 500 nm, 1 μm, 1.2 μm, 1.5 μm, or 1.8 μm, etc. In an embodiment of the present application, in the fiber network layer, the distribution depth of the active material can be 100 nm-1.1 μm. In another embodiment of the present application, in the fiber network layer, the distribution depth of the active material can be 1 μm-1.8 μm.

[0053] In an embodiment of the present application, the thickness of the fiber network layer 12 is 100 nm-2 μm, and a suitable thickness can maintain excellent binding capacity and electrical conductivity of the electrode, and reduce the impedance of the electrode. Specifically, the thickness of the fiber network layer can be, but is not limited to, 100 nm, 200 nm, 500 nm, 800 nm, 1 μm, 1.5 μm, or 2 μm, etc. In an embodiment of the present application, the thickness of the fiber network layer can be 400 nm-1 μm, which can further improve the binding capacity and electrical conductivity of the electrode.

[0054] Referring to FIG. 2, a flow chart of a preparation method provided in an embodiment of the present application is shown, which includes:

[0055] S101: forming a fiber network layer on the surface of the current collector;

[0056] S102: disposing an active material on the surface of the fiber network layer to obtain an electrode. The preparation method provided in the present application is novel, and the preparation process is simple, and an electrode with high electrical conductivity, strong binding capacity, and good cycle stability can be prepared. The electrode described in any one of the above embodiments can be prepared by the method.

[0057] In an embodiment of the present application, the conductive polymer solution includes a conductive polymer, and the conductive polymer solution is used to form the fiber network layer on the surface of the current collector by electrospinning, melt spinning, solution spinning, gel spinning, or template method. Specifically, the conductive polymer can include, but is not limited to, one or more of conductive polyaniline, conductive polypyrrole, and conductive polythiophene. In an embodiment of the present application, the conductive polymer can be conductive polyaniline. In another embodiment of the present application, the conductive polymer can be conductive polypyrrole and conductive polythiophene. In an embodiment of the present application, the method of using the conductive polymer solution to form the fiber network layer on the surface of the current collector can be melt spinning.

[0058] In an embodiment of the present application, the mass percentage of the conductive polymer in the conductive polymer solution is 2%-10%, and a suitable amount of the conductive polymer can improve the binding capacity and conductive capacity of the fiber network layer. Specifically, the mass percentage of the conductive polymer can be, but is not limited to, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, or 10%, etc. In an embodiment of the present application, the mass percentage of the conductive polymer in the conductive polymer solution can be 2%-6%. In another embodiment of the present application, the mass percentage of the conductive polymer in the conductive polymer solution can be 5%-10%.

[0059] In an embodiment of the present application, the preparation method of the conductive polymer solution includes:

[0060] adding a polymer monomer to a protonic acid solution, adding an oxidizing agent, and obtaining the conductive polymer after reaction;

[0061] The conductive polymer is dissolved in a solvent to obtain a conductive polymer solution.

[0062] In an embodiment of the present application, the polymer monomer can include, but is not limited to, one or more of aniline, pyrrole, and thiophene. In an embodiment of the present application, the polymer monomer can be aniline. In another embodiment of the present application, the polymer monomer can be pyrrole and thiophene.

[0063] In an embodiment of the present application, the protonic acid solution can convert the non-conductive polymer monomer into a conductive polymer under the action of the oxidizing agent, improve the conductivity of the polymer, and be conducive to improving the electrical conductivity of the fiber network layer. Specifically, the protonic acid solution can include, but is not limited to, one or more of hydrochloric acid, sulfuric acid, camphor sulfonic acid, and dodecyl benzene sulfonic acid. In an embodiment of the present application, the protonic acid can be sulfuric acid. In another embodiment of the present application, the protonic acid can be hydrochloric acid.

[0064] In an embodiment of the present application, the polymer monomer is added to the protonic acid solution and then stirred for 20 minutes to 60 minutes, which can promote the dispersion of the polymer monomer in the protonic acid solution, promote the reaction, and improve the conductivity of the conductive polymer. Specifically, the stirring time can include, but is not limited to, 20 minutes, 30 minutes, 40 minutes, 45 minutes, 50 minutes, 55 minutes, or 60 minutes, etc. In an embodiment of the present application, the stirring time can be 20 minutes to 40 minutes. In another embodiment of the present application, the stirring time can be 30 minutes to 60 minutes.

[0065] In an embodiment of the present application, the stirring temperature is less than or equal to 5°C, which can avoid the adverse effects of overheating on the reaction. Specifically, the stirring temperature can include, but is not limited to, less than or equal to 5°C, less than or equal to 3°C, less than or equal to 1°C, or less than or equal to 0°C, etc. In an embodiment of the present application, the stirring temperature can be less than or equal to 2°C. In another embodiment of the present application, the stirring temperature can be less than or equal to 0°C.

[0066] In an embodiment of the present application, the oxidizing agent can cause the organic compound to undergo a redox reaction in the protonic acid solution, form a protonic acid-doped polymer, produce a highly delocalized polycation or / and polyanion, improve the conductivity of the polymer, and be conducive to improving the electrical conductivity of the fiber network layer. Specifically, the oxidizing agent can include, but is not limited to, one or more of ammonium persulfate, hydrochloric acid, sulfuric acid, p-toluenesulfonic acid, and trifluoroacetic acid. In an embodiment of the present application, the oxidizing agent can be ammonium persulfate.

[0067] In an embodiment of the present application, the standing treatment is performed after the addition of the oxidizing agent, and the standing treatment is performed for 20-30 hours, which can promote the complete redox reaction. Specifically, the standing treatment can be performed for 20, 22, 24, 26, 28 or 30 hours, but is not limited thereto. In an embodiment of the present application, the standing treatment can be performed for 20-26 hours. In another embodiment of the present application, the standing treatment can be performed for 25-30 hours.

[0068] In the present application, the conductivity of the conductive polymer can be adjusted by adjusting the reaction conditions, such as the standing time.

[0069] In an embodiment of the present application, the washing is performed using a washing liquid after the standing treatment, and the washing liquid can remove the unreacted oxidizing agent and the protonic acid solution. Specifically, the washing liquid can be water and / or acetone, but is not limited thereto. In an embodiment of the present application, the washing liquid includes water and acetone, and the washing is performed using water and acetone after the standing treatment, which can improve the conductivity of the conductive polymer solution.

[0070] In an embodiment of the present application, the drying treatment is performed after the washing, and the drying treatment is performed at a temperature of 40-80°C for 12-36 hours. Specifically, the drying treatment can be performed at a temperature of 40, 45, 50, 55, 60, 70 or 80°C for 12, 15, 18, 20, 22, 25, 28, 30 or 36 hours, but is not limited thereto. In an embodiment of the present application, the drying treatment can be performed at a temperature of 40-70°C for 12-25 hours. In another embodiment of the present application, the drying treatment can be performed at a temperature of 50-80°C for 20-36 hours.

[0071] In an embodiment of the present application, the solvent can promote the complete dissolution of the polymer precursor, which can facilitate the deposition of the fiber network layer. Specifically, the solvent can be one or more of concentrated sulfuric acid, N,N-dimethylformamide, N-methylpyrrolidone and chloromethane, but is not limited thereto. In an embodiment of the present application, the solvent can be concentrated sulfuric acid. In an embodiment of the present application, the solvent can be N-methylpyrrolidone.

[0072] In an embodiment of the present application, the method for forming the fiber network layer on the surface of the current collector using the conductive polymer solution is an electrospinning method, and the electrospinning voltage is 10-30 kV. Specifically, the electrospinning voltage can be 10, 15, 20, 25 or 30 kV, but is not limited thereto. In an embodiment of the present application, the electrospinning voltage can be 10-25 kV. In another embodiment of the present application, the electrospinning voltage can be 20-30 kV.

[0073] In an embodiment of the present application, the polymer conductive solution is filled into the spray head, and the distance between the spray head and the current collector is 10-20 cm. Specifically, the distance between the spray head and the current collector can be, but is not limited to, 10 cm, 12 cm, 14 cm, 16 cm, 18 cm or 20 cm, etc. In an embodiment of the present application, the distance between the spray head and the current collector can be 10-18 cm. In another embodiment of the present application, the distance between the spray head and the current collector can be 14-20 cm.

[0074] In an embodiment of the present application, the diameter of the spray head is 0.6-1.6 mm, which is beneficial to control the diameter of the fibers in the fiber network layer and improve the conductivity and binding capacity of the fiber network layer. Specifically, the diameter of the spray head can be, but is not limited to, 0.6 mm, 0.8 mm, 1 mm, 1.2 mm, 1.4 mm or 1.6 mm, etc. In an embodiment of the present application, the diameter of the spray head can be 0.6-1.2 mm. In another embodiment of the present application, the diameter of the spray head can be 1-1.6 mm.

[0075] In the present application, the porosity or pore size of the fiber network layer can be adjusted by adjusting the conditions of electrospinning, such as the electrospinning time, the electrospinning voltage or the concentration of the conductive polymer solution, etc.

[0076] In an embodiment of the present application, the drying temperature is 60-100℃, which is beneficial to the formation of the fiber network layer and improves the binding force between the current collector and the active material layer. Specifically, the drying temperature can be, but is not limited to, 60℃, 70℃, 80℃, 90℃ or 100℃, etc. In an embodiment of the present application, the drying temperature can be 60-80℃, and the drying mode can be vacuum drying. In another embodiment of the present application, the drying temperature can be 80-100℃.

[0077] In an embodiment of the present application, the electrode slurry is a positive electrode slurry or a negative electrode slurry. When the electrode slurry is a positive electrode slurry, the electrode is a positive electrode. When the electrode slurry is a negative electrode slurry, the electrode is a negative electrode. In an embodiment of the present application, when the electrode slurry is a positive electrode slurry, the electrode slurry comprises a positive active material (lithium iron phosphate material), a positive conductive agent (carbon black) and a positive binder (polyvinylidene fluoride). In another embodiment of the present application, when the electrode slurry is a negative electrode slurry, the electrode slurry comprises a negative active material (graphite), a negative conductive agent (carbon black) and a negative binder (sodium carboxymethyl cellulose and styrene butadiene rubber emulsion).

[0078] In an embodiment of the present application, after the electrode slurry is coated on the surface of the fiber network layer to form the active material layer, the electrode is obtained by rolling. The rolling can promote the active material in the active material layer to be embedded in the fiber network layer, the filamentous structure of the fiber and the active material layer form a mechanical action, the bonding capacity between the fiber network layer and the active material layer is improved, the active material layer is not easy to fall off, and the structural stability and service life of the electrode are improved.

[0079] In an embodiment of the present application, the temperature of the rolling is 60-90°C. The suitable rolling temperature can further improve the bonding capacity between the fiber network layer and the active material layer, and improve the structural stability of the electrode. Specifically, the temperature of the rolling can be, but is not limited to, 60°C, 65°C, 70°C, 75°C, 80°C, 85°C or 90°C, etc. In an embodiment of the present application, the temperature of the rolling can be 65-85°C, which can further promote the bonding of the active material layer and the fiber network layer, improve the bonding capacity therebetween, and improve the peeling strength and mechanical strength of the electrode.

[0080] The present application also provides a battery comprising a positive electrode and a negative electrode, and a separator arranged between the positive electrode and the negative electrode, wherein the positive electrode and / or the negative electrode is prepared by the electrode of any one of the above embodiments or the preparation method of any one of the above embodiments. The electrode provided by the present application has high bonding capacity, high electrical conductivity and good cycle stability, which is beneficial to improve the service life and electrochemical performance of the battery.

[0081] In an embodiment of the present application, the separator can be ion-exchanged to form a complete ion conduction path. Specifically, the separator can be, but is not limited to, a woven film, a non-woven fabric, a microporous film, a composite film, a rolled film or a separator paper, etc. In an embodiment of the present application, the battery further comprises an electrolyte. At least part of the positive electrode and at least part of the negative electrode are soaked in the electrolyte. The electrolyte of the present application is not particularly limited, and can be, but is not limited to, various substances capable of being used as a battery electrolyte in the art.

[0082] The present application also provides a power consuming device comprising the battery of any one of the above embodiments. The power consuming device provided by the present application has good cycle performance, high safety performance and strong market competitiveness. The power consuming device includes a vehicle, an electronic device, an energy storage system, etc. The electronic device can be, for example, a mobile phone, a tablet, a watch, a VR glasses, etc. In an embodiment of the present application, the battery can be used in a vehicle, which can improve the service life and charging rate of the vehicle, improve the wide application of new energy vehicles, and is beneficial to the construction of green and environmentally friendly environment. In another embodiment of the present application, the battery can also be applied to a mobile phone, which can reduce the preparation cost of the battery and improve the use safety of the battery. The above battery of the present application can be arranged in the power consuming device in the form of a single battery, a battery module, a battery pack, etc.

[0083] The effect of the technical scheme of the present application is further described below through specific examples.

[0084] Example 1

[0085] The organic compound (aniline) is dissolved in a protic acid solution (sulfuric acid), stirred for 30 min, then placed in an ice water bath (as low as 5℃ or below), an oxidizing agent (ammonium persulfate) is added, and placed in an ice water bath for 20-30h, washed with water and acetone several times, and vacuum dried at 60℃ for 24h to obtain a conductive polymer (polyaniline) with a conductivity of 50S / cm.

[0086] The conductive polymer is dissolved in a solvent (N-methyl pyrrolidone) to obtain a conductive polymer solution, wherein the mass percentage of the conductive polymer is 5%;

[0087] The conductive polymer solution is loaded into an electrospinning jet head, and the conductive polymer solution is sprayed onto the positive current collector (aluminum foil) through an electrospinning device to obtain a fiber network layer, wherein the diameter of the conductive polymer fiber is 100nm, the average pore size of the fiber network layer is 10μm, the thickness of the fiber network layer is 2μm, and the porosity of the fiber network layer is 40%;

[0088] The positive electrode slurry (LiFePO4, polyvinylidene fluoride, and carbon black with a mass ratio of 100:2.3:1) is coated on the fiber network layer to form a positive active material layer, and the thickness of the positive active material layer is 150μm, and physical heat rolling is performed at 70℃ to obtain a positive electrode.

[0089] Example 2

[0090] The difference from Example 1 is that the thickness of the fiber network layer is 2μm, and the porosity of the fiber network layer is 75%.

[0091] Example 3

[0092] The difference from Example 1 is that the thickness of the fiber network layer is 1μm, and the porosity of the fiber network layer is 45%.

[0093] Example 4

[0094] The difference from Example 1 is that the thickness of the fiber network layer is 1μm, and the porosity of the fiber network layer is 72%.

[0095] Example 5

[0096] The difference from Example 1 is that the thickness of the fiber network layer is 400nm, and the porosity of the fiber network layer is 40%.

[0097] Example 6

[0098] The difference from Example 1 is that the thickness of the fiber network layer is 400 nm, and the porosity of the fiber network layer is 75%.

[0099] Example 7

[0100] The difference from Example 1 is that the thickness of the fiber network layer is 100 nm, and the porosity of the fiber network layer is 65%.

[0101] Example 8

[0102] The difference from Example 1 is that the conductivity of the conductive polymer is 200 S / cm.

[0103] Example 9

[0104] The difference from Example 1 is that the conductivity of the conductive polymer is 500 S / cm.

[0105] Example 10

[0106] The difference from Example 1 is that the fiber network layer is disposed on the negative electrode current collector (copper foil), and the negative electrode active material layer is disposed on the fiber network layer to obtain a negative electrode, and the negative electrode active material layer comprises a negative electrode active material (graphite), a negative electrode conductive agent (carbon black), and a negative electrode binder (sodium carboxymethyl cellulose and styrene butadiene rubber) at a mass ratio of 100:0.8:3.2.

[0107] Comparative Example 1

[0108] The difference from Example 1 is that the positive electrode slurry is directly coated on the positive electrode current collector to obtain a positive electrode.

[0109] Comparative Example 2

[0110] The difference from Example 1 is that the conductive polymer solution is directly coated on the positive electrode current collector without forming a fiber network layer.

[0111] Comparative Example 3

[0112] The difference from Example 10 is that the negative electrode slurry is directly coated on the negative electrode current collector to obtain a negative electrode.

[0113] Comparative Example 4

[0114] The difference from Example 10 is that the conductive polymer solution is directly coated on the negative electrode current collector without forming a fiber network layer.

[0115] Performance detection

[0116] The conductive polymer prepared in the above Examples 1-10 was ground to obtain a conductive polymer powder, which was pressed into a die-circular sheet with a diameter of 14 mm and a thickness of 0.5 mm, and the conductivity of the sheet was tested by using a full-automatic four-probe tester. The testing process was as follows: the sheet was placed in the center of a sample table, and the thickness of the sheet was input. Then, the four-probe probe was slowly lowered to just contact the sample, and the current indicator of the four-probe tester showed a value. After the value was adjusted to be consistent with the value given by the computer, the testing was started. The sheet was tested at five positions, i.e., the middle, the top, the bottom, the left and the right, and the conductivity value of the sheet was obtained.

[0117] The electrodes prepared in the above Examples 1-10 and Comparative Examples 1-4 were subjected to a peeling force test. The testing process was as follows: an adhesive tape was attached to the surface of the electrode, and the electrode was flattened. The sample with the attached tape was cut into a size of 5 cm x 10 cm, and the cut sample was rolled by a roll machine for two rounds (the rolling pressure was 2 kg). The sample was attached to a testing fixture by using a double-sided adhesive tape, and a tensile testing machine was used to test the 180° peeling between the current collector and the fiber network layer. The testing results are shown in Table 1.

[0118] The electrodes prepared in the above Examples 1-10 and Comparative Examples 1-4 were subjected to a resistivity test. The testing process was as follows: the electrodes were cut into samples with a size of 4 cm x 10 cm, and the samples were placed in a two-probe resistivity testing table. The testing pressure was set to 25 kPa, and the pressure holding time was set to 40 s. Each sample was tested at six points, and the average value was taken. The testing results are shown in Table 1.

[0119] The electrodes prepared in the above Examples 1-10 and Comparative Examples 1-4 were subjected to a porosity test. The testing process was as follows: the sample was cut into a suitable size, and then was placed into a sample tube / dilatometer. The sample tube / dilatometer was placed into a mercury injection testing apparatus, and the volume of mercury injection and discharge was measured by using a metal jacket and an electrode cap. According to the data of the pressure and the volume of mercury at different pressures, the average pore size distribution and the porosity were obtained.

[0120] The positive electrodes prepared in the above Examples 1-9 and Comparative Examples 1-2, the negative electrodes (the negative electrodes included copper foils and negative active material layers disposed on the copper foils, and the negative active material layers included graphite, carbon black and a binder (the binder included sodium carboxymethyl cellulose and styrene-butadiene rubber) at a mass ratio of 100:0.8:3.2), separators (polyethylene / polypropylene composite membranes) and electrolytes (the electrolytes were LiPF6 solutions with a concentration of 1.0 mol / L) were assembled to form batteries. The negative electrodes prepared in Examples 10 and Comparative Examples 3-4, the positive electrodes (the positive electrodes included aluminum foils and positive active materials disposed on the aluminum foils, and the positive active materials included LiFePO4, polyvinylidene fluoride and carbon black at a mass ratio of 100:2.3:1), separators (polyethylene / polypropylene composite membranes) and electrolytes (the electrolytes were LiPF6 solutions with a concentration of 1.0 mol / L) were assembled to form batteries.

[0121] The positive or negative electrode of Examples 1-10 and Comparative Examples 1-4 above were assembled into batteries and tested for cycle performance. The test procedure was as follows: 0.5C constant current charging to 3.8V at 45°C, 10 min rest, 0.5C constant current discharging to 2.0V, 10 min rest, and so on for one cycle. After 1000 cycles, the capacity retention rate was calculated as (discharge capacity of the 1000th cycle / discharge capacity of the 1st cycle) x 100%. The test results are shown in Table 2.

[0122] The electrodes of Examples 1-10 and Comparative Examples 1-4 above were tested for mixing capacity. The test procedure was as follows: the electrode mass minus the current collector mass was the mixing mass; the battery of each example and comparative example was assembled and tested for cycle performance. The test procedure was as follows: 0.5C constant current charging to 3.8V at 45°C, 10 min rest, 0.5C constant current discharging to 2.0V, 10 min rest, and so on for one cycle. The mixing capacity was the discharge capacity of the 3rd cycle divided by the mixing mass. The test results are shown in Table 2.

[0123] The batteries of Examples 1-10 and Comparative Examples 1-4 above were tested for internal resistance. The test procedure was as follows: 1 / 3C discharging to 2.0V, 1 / 3C charging to 50% SOC, 2h rest at 25°C, recording the voltage value U1; 1.5C discharging for 30s, recording the voltage value U2; 1h rest, 0.1C charging for 450s, 1h rest; 50% SOC DC internal resistance (DCIR) = (U1-U2) / I, test rate 1.5C, at this time, I = 1.5 x battery capacity. The test results are shown in Table 2.

[0124] Table 1 Performance Test

[0125] Table 2 Battery Performance Test

[0126] According to the embodiments 1-10 and the comparative examples 1-4, it can be seen that the electrode provided by the present application includes the fiber network layer containing the conductive polymer fiber, which can improve the binding force between the active material layer and the current collector, and improve the electrical conductivity and cycle stability of the electrode. According to the embodiments 1 and 10, it can be seen that the fiber network layer can be applied to the positive electrode and the negative electrode, and both can improve the electrical conductivity and mechanical properties. According to the embodiments 1 and 2-9, it can be seen that the appropriate thickness, porosity and electrical conductivity of the conductive polymer of the fiber network layer can improve the binding force between the active material layer and the current collector, improve the electrical conductivity of the motor, and be beneficial to improve the electrochemical performance of the battery. According to the embodiments 1, 10 and the comparative examples 1-4, it can be seen that the fiber network layer containing the conductive polymer fiber can improve the binding force between the active material layer and the current collector, reduce the internal resistance of the battery, and improve the cycle stability of the battery.

[0127] The above describes the preferred embodiments of the present application, but should not be construed as limiting the scope of the present application. It should be noted that for those skilled in the art, without departing from the principles of the present application, a number of improvements and refinements can be made, which are also considered within the scope of protection of the present application.

Claims

1. An electrode (100), characterized in that, The electrode (100) includes a current collector (11), a fiber network layer (12) and an active material layer (13) stacked together. The fiber network layer (12) is disposed between the current collector (11) and the active material layer (13). The fiber network layer (12) includes conductive polymer fibers, which are interwoven into a network structure.

2. The electrode (100) as claimed in claim 1, characterized in that, The conductivity of the conductive polymer fiber is 50S / cm-500S / cm.

3. The electrode (100) as described in claim 1 or 2, characterized in that, The conductive polymer fiber includes one or more of polyaniline fiber, polypyrrole fiber, and polythiophene fiber; and / or The diameter of the conductive polymer fiber is 10nm-200nm.

4. The electrode (100) as claimed in claim 1, characterized in that, The porosity of the fiber network layer (12) is 40%-75%; and / or The average pore size of the fiber network layer (12) is 1μm-30μm.

5. The electrode (100) as claimed in claim 1, characterized in that, The thickness of the fiber network layer (12) is 100nm-2μm.

6. The electrode (100) as claimed in claim 1, characterized in that, The conductive polymer fibers are interwoven into a three-dimensional network structure; The active material layer (13) includes active materials, and the active materials are distributed on the side of the fiber network layer (12) close to the active material layer (13); In the fiber network layer (12), the distribution depth of the active material is 100nm-1.8μm.

7. The electrode (100) as claimed in claim 1 or 6, characterized in that, The active material layer (13) includes an active material, which is a positive electrode active material or a negative electrode active material; The positive electrode active material includes one or more of the following: lithium cobalt oxide material, nickel-cobalt-manganese ternary material, nickel-cobalt-aluminum ternary material, lithium nickel-cobalt-manganese-aluminum oxide, lithium iron phosphate material, lithium manganese phosphate material, lithium vanadium phosphate material, lithium manganese oxide material, and lithium-rich manganese-based material. The negative electrode active material includes one or more of artificial graphite, natural graphite, hard carbon, soft carbon, and graphene.

8. A method for preparing an electrode (100) as described in any one of claims 1-7, characterized in that, include: The fiber network layer (12) is formed on the surface of the current collector (11); The active material is disposed on the surface of the fiber network layer (12) to obtain the electrode (100).

9. The preparation method according to claim 8, characterized in that, The conductive polymer solution is used to form the fiber network layer (12) on the surface of the current collector (11) by electrospinning, melt spinning, solution spinning, gel spinning or template method.

10. The preparation method according to claim 9, characterized in that, The conductive polymer solution comprises a conductive polymer, which includes one or more of conductive polyaniline, conductive polypyrrole, and conductive polythiophene; and / or The conductive polymer solution contains 2%-10% by mass of the conductive polymer.

11. The preparation method according to claim 9, characterized in that, The conductive polymer solution also includes a solvent; The solvent includes one or more of concentrated sulfuric acid, N,N-dimethylformamide, N-methylpyrrolidone, and methyl chloride.

12. The preparation method according to claim 8, characterized in that, The process of setting the active material on the surface of the fiber network layer (12) includes coating the surface of the fiber network layer (12) with an electrode (100) slurry containing the active material.

13. The preparation method according to claim 8, characterized in that, The preparation method further includes rolling the active material after it is placed on the surface of the fiber network layer (12); the rolling temperature is 60℃-90℃.

14. A battery, characterized in that, The battery includes a positive electrode and a negative electrode, and a separator disposed between the positive electrode and the negative electrode, wherein the negative electrode and / or the positive electrode includes an electrode (100) as described in any one of claims 1-7 or an electrode (100) prepared by the preparation method as described in any one of claims 8-13.

15. An electrical appliance, characterized in that, The electrical device includes the battery as described in claim 14.

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