Secondary battery and electronic device

Abstract

To provide a secondary battery and an electronic device in order to improve the coulomb efficiency and cycle characteristic of the secondary battery.SOLUTION: A secondary battery includes a negative electrode piece and a separator. The negative electrode piece includes a three-dimensional skeleton. The three-dimensional skeleton includes a first layer skeleton and a second layer skeleton. The first layer skeleton includes a one-dimensional conductive fiber. The second layer skeleton incudes a zero-dimensional material, a one-dimensional material, and a two-dimensional material. The zero-dimensional material is a lithium-affinity material. Adjusting the thicknesses of the three-dimensional skeleton, the first layer skeleton, and the second layer skeleton, the mass percentage of the zero-dimensional material, and the mass ratio of the one-dimensional material to the two-dimensional material in the range according to the present invention is advantageous in constructing the lithium affinity gradient in the three-dimensional skeleton. Accordingly, lithium metal is advanced into the three-dimensional skeleton and deposited in a bottom-up manner, and the coulomb efficiency and cycle characteristic of the secondary battery are further improved.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to the electrochemical technical field, particularly to secondary batteries and electronic devices. [Background technology]

[0002] Secondary batteries, such as lithium-ion batteries, are widely used in consumer electronics due to their advantages of high energy density, high operating voltage, low self-discharge rate, small volume, and light weight. Lithium metal has the smallest relative atomic mass (6.94) and lowest standard electrode potential (-3.045 V) of all metallic elements. Its theoretical specific capacity reaches 3860 mAh / g, making it one of the metals with the highest specific energy levels discovered to date. In contrast to lithium metal batteries, which incorporate lithium metal into the anode, the use of high-energy-density positive electrode materials (e.g., lithium cobalt oxide, lithium iron phosphate, lithium manganese oxide, lithium nickel cobalt manganese oxide, and lithium nickel cobalt aluminate) can increase the energy density and operating voltage of lithium metal batteries. However, lithium metal continually accumulates during charging, resulting in lithium dendrites and dead lithium. Lithium metal constantly expands and contracts during charging and discharging, which can cause the solid electrolyte interfacial membrane (SEI) to peel off and fracture, thereby affecting the coulombic efficiency and cycle characteristics of lithium metal batteries. Summary of the Invention

[0003] The present invention aims to provide a secondary battery and an electronic device for improving the coulombic efficiency and cycle characteristics of the secondary battery. Specific technical solutions are as follows.

[0004] In the Summary of the Invention, the present invention will be described using a lithium metal battery as an example of a secondary battery, but the secondary battery of the present invention is not limited to a lithium metal battery.

[0005] A first aspect of the present invention provides a secondary battery comprising a negative electrode piece and a separator, the negative electrode piece comprising a three-dimensional skeleton, the three-dimensional skeleton comprising a first layer skeleton and a second layer skeleton, the first layer skeleton comprising one-dimensional conductive fibers, the second layer skeleton comprising a zero-dimensional material, a one-dimensional material, and a two-dimensional material, the zero-dimensional material being a lithiophilic material, the three-dimensional skeleton having a thickness of 10 μm to 200 μm, the first layer skeleton having a thickness of 0 μm to 10 μm, and the second layer skeleton having a thickness of 10 μm to 200 μm, preferably 30 μm to 180 μm, and 30 μm to 80 μm. The zero-dimensional material accounts for 1% to 30% by mass of the second-layer framework, preferably 1% to 10% by mass, and the mass ratio of the one-dimensional material to the two-dimensional material is 1:7 to 20:1. Adjusting the thickness of the three-dimensional framework, the thickness of the first-layer framework, the thickness of the second-layer framework, the mass percentage of the zero-dimensional material, and the mass ratio of the one-dimensional material to the two-dimensional material within the above ranges is advantageous for establishing a lithium affinity gradient in the three-dimensional framework, thereby allowing lithium metal to penetrate the interior of the three-dimensional framework and deposit bottom-up, reducing the formation of lithium dendrites and dead lithium, and further improving the coulombic efficiency and cycle characteristics of secondary batteries. Furthermore, the deposition of lithium metal in the voids of the three-dimensional framework suppresses the volumetric expansion of lithium metal, thereby improving the expansion characteristics of secondary batteries.

[0006] In some embodiments of the present invention, the negative electrode piece includes a metallic lithium layer, the second layer skeleton is located between the first layer skeleton and the metallic lithium layer, and the metallic lithium layer has a thickness of 1 μm to 100 μm, preferably 5 μm to 50 μm. Introducing a metallic lithium layer into the negative electrode piece and adjusting the thickness of the metallic lithium layer within the range of the present invention is advantageous for offsetting lithium loss due to irreversible reactions during the initial charging of the secondary battery, thereby advantageous for improving the cycle characteristics of the secondary battery.

[0007] In some embodiments of the present invention, the particle size of the zero-dimensional material is 0.1 μm to 5 μm, preferably 0.1 μm to 1 μm. Adjusting the particle size of the zero-dimensional material within the range of the present invention is advantageous for inducing lithium metal deposition, which is advantageous for improving the coulombic efficiency and cycle characteristics of the secondary battery.

[0008] In some embodiments of the present invention, the one-dimensional material has a diameter of 1 nm to 2000 nm and an aspect ratio of 0.1 to 20000, preferably a diameter of 1 nm to 300 nm and an aspect ratio of 0.67 to 20000, and more preferably a diameter of 1 nm to 50 nm and an aspect ratio of 5000 to 20000. Adjusting the diameter and aspect ratio of the one-dimensional material within the ranges of the present invention is advantageous for improving electronic conduction in the three-dimensional framework, which is therefore advantageous for improving the Coulombic efficiency and cycle characteristics of the secondary battery.

[0009] In some embodiments of the present invention, the particle size of the zero-dimensional material is 0.1 μm to 5 μm, and the one-dimensional material has a diameter of 0.001 μm to 2 μm and an aspect ratio of 0.1 to 20,000, preferably the particle size of the zero-dimensional material is 0.1 μm to 1 μm, and the one-dimensional material has a diameter of 0.001 μm to 0.3 μm and an aspect ratio of 0.67 to 20,000. Adjusting the particle size of the zero-dimensional material, the diameter of the one-dimensional material, and the aspect ratio of the one-dimensional material within the above ranges is advantageous for inducing lithium metal deposition and for improving electronic conduction in the three-dimensional framework, which is advantageous for improving the Coulombic efficiency and cycle characteristics of the secondary battery.

[0010] In some embodiments of the present invention, the two-dimensional material comprises a titanium element, a carbon element, and a surface group, the surface group comprising at least one of -F, -O, and -OH. The selection of the two-dimensional material is advantageous for uniforming the flow of lithium ions and improving the uniformity of lithium metal deposition, thereby improving the coulombic efficiency and cycle characteristics of the secondary battery.

[0011] In some embodiments of the present invention, when the electrical conductivity of the one-dimensional material is a, a≧1×10 -6 S / cm, and when the conductivity of the 2D material is b, b satisfies b≧2 S / cm, and a and b satisfy b>a. The conductivity of the 1D and 2D materials within the above ranges indicates that the 1D and 2D materials have good electronic conductivity. At the same time, by adjusting a, b, and the relationship between a and b within the above ranges, the 1D material forms a conductive network in the second layer framework, improving the electronic conductivity of the 3D framework. The different structures of the 0D, 1D, and 2D materials result in differences in electrical conductivity and lithium affinity. This allows the 3D framework to have a specific electronic conductivity gradient and lithium affinity gradient, and lithium metal is further deposited bottom-up. Therefore, the secondary battery provided by the present invention has high Coulombic efficiency and good cycle characteristics.

[0012] In some embodiments of the present invention, the one-dimensional conductive fiber comprises at least one of a multi-walled carbon nanotube, a carbon nanofiber, a silver thread, and a nickel thread; the zero-dimensional material comprises at least one of a metal material, an oxide, a nitride, a sulfide, and a carbide; the metal material comprises at least one of Ag, Au, Zn, and alloys thereof; the oxide comprises at least one of TiO2, SiO2, ZnO, SnO2, Co3O4, and Fe2O3; the nitride comprises Mo2N3 and / or Fe6N3; the sulfide comprises MoS2 and / or SnS2; the carbide comprises FeC; the one-dimensional material comprises at least one of a multi-walled carbon nanotube, a carbon nanofiber, a silver thread, and a nickel thread; and the two-dimensional material comprises MXene and / or graphene (Gr). By selecting the above-mentioned one-dimensional conductive fibers, zero-dimensional materials, one-dimensional materials, and two-dimensional materials, it is advantageous to construct a dual gradient of electronic conductivity and lithium affinity in the three-dimensional framework, which is advantageous to improve the electronic conduction in the negative electrode piece, induce lithium metal to penetrate into the three-dimensional framework and deposit from the bottom up, and also advantageous to reduce the formation of lithium dendrites and dead lithium, and further improve the coulombic efficiency and cycle characteristics of the secondary battery.

[0013] In some embodiments of the present invention, the surface of the zero-dimensional material comprises a wetting group, the wetting group comprising at least one of -OH, -COOR, -COOH, -NH, and -SOH, where R in -COOR is selected from the group consisting of a methyl group, an ethyl group, a propyl group, a vinyl group, and an ethynyl group. The wetting group is advantageous for guiding lithium metal deposition and improving the uniformity of lithium metal deposition, thereby improving the coulombic efficiency and cycle characteristics of the secondary battery.

[0014] In some embodiments of the present invention, the porosity of the three-dimensional framework satisfies a porosity of ≥ 80%, which is advantageous for providing space for lithium metal deposition, thereby improving the coulombic efficiency and cycle characteristics of the secondary battery.

[0015] In some embodiments of the invention, the three-dimensional framework is 2 When lithium metal is deposited on the three-dimensional framework, the thickness change rate is less than 10%, which indicates that the volume change of the three-dimensional framework is small during the process of lithium deposition on the three-dimensional framework, which is advantageous for reducing the thickness expansion rate of the negative electrode piece, and indicates that the secondary battery provided by the present invention has a low thickness expansion rate.

[0016] A second aspect of the present invention provides an electronic device including the secondary battery according to any one of the preceding embodiments. The secondary battery provided by the present invention has high coulombic efficiency and cycle characteristics, and the resulting secondary battery has high coulombic efficiency and cycle characteristics.

[0017] Beneficial effects of the present invention: The present invention provides a secondary battery comprising a negative electrode piece and a separator, the negative electrode piece comprising a three-dimensional skeleton, the three-dimensional skeleton comprising a first layer skeleton and a second layer skeleton, the first layer skeleton comprising one-dimensional conductive fibers, the second layer skeleton comprising a zero-dimensional material, a one-dimensional material, and a two-dimensional material, the zero-dimensional material being a lithium affinity material, the thickness of the three-dimensional skeleton being 10 μm to 200 μm, the thickness of the first layer skeleton being 0 μm to 10 μm, the thickness of the second layer skeleton being 10 μm to 200 μm, the zero-dimensional material being 1% to 30% by mass relative to the mass of the second layer skeleton, and the mass ratio of the one-dimensional material to the two-dimensional material being 1:7 to 20:1. The negative electrode piece of the secondary battery provided by the present invention comprises a three-dimensional skeleton. Adjusting the thickness of the three-dimensional framework, the thickness of the first layer framework, the thickness of the second layer framework, the mass percentage of the zero-dimensional material, and the mass ratio of the one-dimensional material to the two-dimensional material within the above ranges is advantageous for establishing a lithium affinity gradient in the three-dimensional framework, thereby allowing lithium metal to penetrate the interior of the three-dimensional framework and deposit bottom-up, reducing the formation of lithium dendrites and dead lithium, and further improving the coulombic efficiency, cycle performance, and safety characteristics of secondary batteries. Specifically, the first layer framework is advantageous for improving the electronic conductivity of the three-dimensional framework. Regarding the second layer framework, the zero-dimensional material has a tip effect and is a lithium affinity material. It is dispersed in the two-dimensional material, which can reduce the nucleation overpotential of lithium metal and induce lithium metal deposition. Meanwhile, the zero-dimensional material is a lithium affinity material, which can uniformly distribute lithium ions and improve the uniformity of lithium metal deposition. Furthermore, the different structures of the zero-dimensional, one-dimensional, and two-dimensional materials result in differences in lithium affinity. This allows the 3D framework to have a specific lithium affinity gradient, allowing lithium metal to be deposited bottom-up. Furthermore, the 2D material is a matrix of the 0D and 1D materials, and the resulting 3D framework has high porosity and a high specific surface area, providing space for lithium metal deposition.Therefore, the formation of lithium dendrites and dead lithium is reduced, and the coulombic efficiency, cycle characteristics, and safety characteristics of the secondary battery provided by the present invention are improved. In addition, the deposition of lithium metal in the voids in the three-dimensional framework suppresses the volume expansion of lithium metal, thereby improving the expansion characteristics of the secondary battery.

[0018] Of course, any product or method embodying the present invention need not necessarily achieve all of the above advantages simultaneously. [Brief explanation of the drawings]

[0019] In order to more clearly describe the embodiments of the present invention or the technical solutions of the prior art, the following will briefly describe the drawings that need to be used in the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments of the present invention, and those skilled in the art can also obtain other embodiments based on these drawings. [Figure 1] FIG. 1 is a schematic diagram of the structure of a three-dimensional scaffold according to some embodiments of the present invention. [Figure 2] FIG. 2 is a scanning electron microscope photograph of the three-dimensional framework according to Example 1 of the present invention. [Figure 3] FIG. 3 shows capacity fade curves of the lithium metal batteries according to Example 1 of the present invention and Comparative Example 4. DETAILED DESCRIPTION OF THE INVENTION

[0020] The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the drawings in the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments in the present invention, all other embodiments that those skilled in the art can obtain based on the present invention fall within the protection scope of the present invention.

[0021] In the Summary of the Invention, the present invention will be described using a lithium metal battery as an example of a secondary battery, but the secondary battery of the present invention is not limited to a lithium metal battery.

[0022] The present invention provides a secondary battery and an electronic device for improving the coulomb efficiency and cycle life of the secondary battery. Specific technical solutions are as follows:

[0023] A first aspect of the present invention provides a secondary battery comprising a negative electrode piece and a separator, wherein the negative electrode piece comprises a three-dimensional skeleton, wherein the three-dimensional skeleton comprises a first layer skeleton and a second layer skeleton, wherein the first layer skeleton comprises one-dimensional conductive fibers, and the second layer skeleton comprises a zero-dimensional material, a one-dimensional material, and a two-dimensional material, wherein the zero-dimensional material is a lithium affinity material, and wherein the thickness of the three-dimensional skeleton is 10 μm to 200 μm, the thickness of the first layer skeleton is 0 μm to 10 μm, and the thickness of the second layer skeleton is 10 μm to 200 μm, preferably 30 μm to 180 μm, and 30 μm to 80 μm. For example, the thickness of the three-dimensional scaffold may be 10 μm, 20 μm, 30 μm, 40 μm, 60 μm, 80 μm, 100 μm, 120 μm, 140 μm, 160 μm, 180 μm, 200 μm, or a range consisting of any two values ​​therein. For example, the thickness of the first layer scaffold may be 0 μm, 2 μm, 4 μm, 6 μm, 8 μm, 10 μm, or a range consisting of any two values ​​therein. For example, the thickness of the second layer scaffold may be 10 μm, 20 μm, 30 μm, 40 μm, 60 μm, 80 μm, 100 μm, 120 μm, 140 μm, 160 μm, 180 μm, 200 μm, or a range consisting of any two values ​​therein. The mass percentage of the zero-dimensional material relative to the mass of the second layer framework is 1% to 30%, preferably 1% to 10%. For example, the mass percentage of the zero-dimensional material may be 1%, 5%, 10%, 15%, 20%, 25%, 30%, or any two-value range therein. The mass ratio of the one-dimensional material to the two-dimensional material is 1:7 to 20:1. For example, the mass ratio of the one-dimensional material to the two-dimensional material may be 1:7, 2:1, 4:1, 6:1, 8:1, 10:1, 12:1, 14:1, 16:1, 18:1, 20:1, or any two-value range therein. In the present invention, the lithium affinity material refers to a material that can interact with lithium ions and induce lithium deposition. A zero-dimensional material refers to a particulate material, and the particles may be regular, e.g., spherical, or irregular, resembling a sphere. A one-dimensional material refers to a wire-like material. A two-dimensional material refers to a sheet-like material.

[0024] FIG. 1 is a schematic diagram illustrating a three-dimensional framework according to some embodiments of the present invention. Zero-dimensional material 11 is shown in particle form, one-dimensional material 12 is shown in wire form, and two-dimensional material 13 is shown in sheet form. It can be seen that zero-dimensional material 11, one-dimensional material 12, and two-dimensional material 13 together constitute a three-dimensional framework. Here, the one-dimensional conductive fibers in the first layer framework are advantageous for improving the electronic conductivity of the three-dimensional framework. Regarding the second layer framework, the zero-dimensional material has a tip effect and is a lithium-affinity material. It is dispersed in the two-dimensional material, which can reduce the nucleation overpotential of lithium metal and induce lithium metal deposition. Meanwhile, the zero-dimensional material is a lithium-affinity material, which can uniformly distribute lithium ions and improve the uniformity of lithium metal deposition. Furthermore, the different compositions of the zero-dimensional material, one-dimensional material, and two-dimensional material result in differences in lithium affinity. This allows the three-dimensional framework to have a specific lithium affinity gradient, allowing lithium metal to be deposited bottom-up. Furthermore, the 2D material, acting as a matrix for the 0D and 1D materials, forms a 3D framework with high porosity and a high specific surface area, providing space for lithium metal deposition. This reduces the formation of lithium dendrites and dead lithium, improving the coulombic efficiency, cycle characteristics, and safety characteristics of the secondary battery provided by the present invention. Furthermore, the deposition of lithium metal in the voids in the 3D framework suppresses the volumetric expansion of the lithium metal, thereby improving the expansion characteristics of the secondary battery.

[0025] Specifically, if the thickness of the three-dimensional framework is too small (e.g., less than 10 μm), the lithium affinity gradient formed in the framework is not obvious, resulting in a low energy difference, which is unfavorable for lithium metal deposition, thereby affecting the Coulombic efficiency and cycle characteristics of the secondary battery. If the thickness of the three-dimensional framework is too large (e.g., more than 200 μm), it is unfavorable for electron conduction in the framework, affecting the current density of the secondary battery and causing side reactions, thereby affecting the Coulombic efficiency and cycle characteristics of the secondary battery. If the thickness of the first layer framework is too large (e.g., more than 10 μm), it affects the transport of electrons and lithium ions, thereby affecting the Coulombic efficiency and cycle characteristics of the secondary battery. If the thickness of the second layer framework is too small (e.g., less than 10 μm), it does not provide enough space for lithium metal deposition, thereby affecting the Coulombic efficiency and cycle characteristics of the secondary battery. If the thickness of the second layer framework is too large (e.g., greater than 200 μm), it will reduce the current density of the secondary battery and cause side reactions, thereby affecting the coulombic efficiency of the secondary battery. If the mass percentage of the zero-dimensional material is too small (e.g., less than 1%), it will be unfavorable to induce lithium metal deposition in the three-dimensional framework, thereby affecting the cycle characteristics of the secondary battery. If the mass percentage of the zero-dimensional material is too large (e.g., greater than 30%), the zero-dimensional materials will easily aggregate with each other, and because the zero-dimensional material is a lithium-affinity material, too much lithium ion will be consumed, thereby affecting the coulombic efficiency and cycle characteristics of the secondary battery. If the mass ratio of the one-dimensional material to the two-dimensional material in the three-dimensional framework is small (e.g., less than 1:7), i.e., if the one-dimensional material is too little, it will be difficult to form a lithium-affinity gradient, which will affect the deposition of lithium metal. If the mass ratio of the one-dimensional material to the two-dimensional material in the three-dimensional framework is large (e.g., greater than 20:1), i.e., if there is too little two-dimensional material, the two-dimensional material will be unable to support the three-dimensional framework, and the distribution uniformity of the zero-dimensional material in the three-dimensional framework will be reduced, thereby affecting the coulombic efficiency and cycle characteristics of the secondary battery.Therefore, adjusting the thickness of the three-dimensional framework, the thickness of the first layer framework, the thickness of the second layer framework, the mass percentage of the zero-dimensional material, and the mass ratio of the one-dimensional material to the two-dimensional material within the above ranges is advantageous for establishing a lithium affinity gradient in the three-dimensional framework, thereby inducing lithium metal to enter the three-dimensional framework and deposit it bottom-up, which is advantageous for reducing the formation of lithium dendrites and dead lithium, and further improving the coulombic efficiency and cycle characteristics of the secondary battery.

[0026] In some embodiments of the present invention, the negative electrode piece includes a metallic lithium layer, and a second layer skeleton is located between the first layer skeleton and the metallic lithium layer. The thickness of the metallic lithium layer is 1 μm to 100 μm, preferably 5 μm to 50 μm. For example, the thickness of the metallic lithium layer may be 1 μm, 20 μm, 40 μm, 60 μm, 80 μm, 100 μm, or a range consisting of any two values ​​therein. Introducing a metallic lithium layer into the negative electrode piece and adjusting the thickness of the metallic lithium layer within the range of the present invention is advantageous in offsetting lithium loss due to irreversible reactions during the initial charge of the secondary battery, thereby improving the cycle characteristics of the secondary battery.

[0027] In some embodiments of the present invention, the particle size of the zero-dimensional material is 0.1 μm to 5 μm, preferably 0.1 μm to 1 μm. For example, the particle size of the zero-dimensional material may be 0.1 μm, 1 μm, 2 μm, 3 μm, 4 μm, 5 μm, or a range consisting of any two of these values. Adjusting the particle size of the zero-dimensional material within the range of the present invention is advantageous for inducing lithium metal deposition and improving the uniformity of lithium metal deposition, which is therefore advantageous for improving the coulombic efficiency and cycle characteristics of the secondary battery.

[0028] In some embodiments of the present invention, the one-dimensional material has a diameter of 1 nm to 2000 nm and an aspect ratio of 0.1 to 20000, preferably a diameter of 1 nm to 300 nm and an aspect ratio of 0.67 to 20000, and more preferably a diameter of 1 nm to 50 nm and an aspect ratio of 5000 to 20000. For example, the diameter of the one-dimensional material is 1 nm, 1.5 nm, 2 nm, 2.5 nm, 3 nm, 5 nm, 10 nm, 50 nm, 100 nm, 250 nm, 500 nm, 1000 nm, 1500 nm, 2000 nm, or a range consisting of any two numbers therein. For example, the aspect ratio of the one-dimensional material may be 0.1, 0.67, 1, 1000, 2500, 5000, 6000, 7000, 7500, 8500, 9500, 10000, 12500, 13500, 14500, 15000, 17500, 20000, or a range consisting of any two values ​​therein. Adjusting the diameter and aspect ratio of the one-dimensional material within the range of the present invention is advantageous for improving electronic conduction in the three-dimensional framework, which is therefore advantageous for improving the coulombic efficiency and cycle characteristics of the secondary battery.

[0029] In some embodiments of the present invention, the particle size of the zero-dimensional material is 0.1 μm to 5 μm. The one-dimensional material has a diameter of 0.001 μm to 2 μm and an aspect ratio of 0.1 to 20,000, preferably 0.1 μm to 1 μm. The one-dimensional material has a diameter of 0.001 μm to 0.3 μm and an aspect ratio of 0.67 to 20,000. Adjusting the particle size of the zero-dimensional material, the diameter of the one-dimensional material, and the aspect ratio of the one-dimensional material within the above ranges is advantageous for inducing lithium metal deposition and for improving electronic conduction in the three-dimensional framework, which is advantageous for improving the Coulombic efficiency and cycle characteristics of the secondary battery.

[0030] In some embodiments of the present invention, the two-dimensional material comprises a titanium element, a carbon element, and a surface group, the surface group comprising at least one of -F, -O, and -OH. The selection of the two-dimensional material is advantageous for uniformly facilitating the flow of lithium ions and improving the uniformity of lithium metal deposition, thereby improving the coulombic efficiency and cycle characteristics of the secondary battery.

[0031] In some embodiments of the present invention, the electrical conductivity of the one-dimensional material is a, where a is greater than or equal to 1×10 -6 S / cm, and when the conductivity of the two-dimensional material is b, b satisfies b≧2S / cm, and a and b satisfy b>a. Preferably, when the conductivity of the one-dimensional material is a, a is 1×10 -6 S / cm≦a≦5000S / cm is satisfied, and the conductivity of the two-dimensional material is b, then b satisfies 2S / cm≦b≦50000S / cm. For example, the conductivity of a one-dimensional material is 1×10 -6 S / cm, 1×10 -5 S / cm, 1×10 -4 S / cm, 1×10 -3 S / cm, 1×10 -2 S / cm, 1×10 -1S / cm, 1S / cm, 40S / cm, 60S / cm, 80S / cm, 86S / cm, 90S / cm, 95S / cm, 100S / cm, 105S / cm, 150S / cm, 200S / cm, 300S / cm, 400S / cm, 500S / cm, 2000S / cm, 5000S / cm, or a range consisting of any two of these values. For example, the conductivity of a two-dimensional material may be 2 S / cm, 5 S / cm, 50 S / cm, 150 S / cm, 300 S / cm, 450 S / cm, 500 S / cm, 600 S / cm, 700 S / cm, 750 S / cm, 800 S / cm, 850 S / cm, 900 S / cm, 1000 S / cm, 5000 S / cm, 50,000 S / cm, or a range consisting of any two values ​​therein. The conductivity of one-dimensional and two-dimensional materials within these ranges indicates that the one-dimensional and two-dimensional materials have good electronic conductivity. At the same time, adjusting a, b, and the relationship between a and b within these ranges allows the one-dimensional material to form a conductive network in the second layer framework, improving the electronic conductivity of the three-dimensional framework. Note that the different structures of zero-dimensional, one-dimensional, and two-dimensional materials result in differences in electrical conductivity and lithium affinity. This allows the three-dimensional framework to have a specific electron conductivity gradient and lithium affinity gradient, and lithium metal to be deposited bottom-up, resulting in a secondary battery with high coulombic efficiency and good cycle characteristics.

[0032] In some embodiments of the present invention, the one-dimensional conductive fibers include at least one of multi-walled carbon nanotubes (CNTs), carbon nanofibers (CNFs), silver threads, and nickel threads. The zero-dimensional materials include at least one of metal materials, oxides, nitrides, sulfides, and carbides. The metal materials include at least one of Ag, Au, Zn, and alloys thereof. The oxides include at least one of TiO2, SiO2, ZnO, SnO2, Co3O4, and Fe2O3. The nitrides include Mo2N3 and / or Fe6N3. The sulfides include MoS2 and / or SnS2. The carbides include FeC. The one-dimensional materials include at least one of multi-walled carbon nanotubes, carbon nanofibers, silver threads, and nickel threads. The two-dimensional materials include MXene and / or graphene (Gr). The zero-dimensional materials are good lithium affinity materials, and the one-dimensional and two-dimensional materials are good electrical conductors with good electronic conductivity. The selection of the above-mentioned one-dimensional conductive fibers, zero-dimensional materials, one-dimensional materials, and two-dimensional materials is advantageous in constructing a dual gradient of electronic conductivity and lithium affinity in the three-dimensional framework, which is advantageous in improving electronic conduction in the anode piece, inducing lithium metal to penetrate the three-dimensional framework and deposit it bottom-up, and also advantageous in reducing the formation of lithium dendrites and dead lithium, further improving the coulombic efficiency and cycle characteristics of the secondary battery. In the present invention, the diameter and aspect ratio of the one-dimensional conductive fibers are not particularly limited as long as the objectives of the present invention are achieved. For example, the one-dimensional conductive fibers may have a diameter of 0.001 μm to 2 μm and an aspect ratio of 0.1 to 20,000.

[0033] In some embodiments of the present invention, the surface of the zero-dimensional material comprises a wetting group, the wetting group comprising at least one of -OH, -COOR, -COOH, -NH, and -SOH, where R in -COOR is at least one selected from the group consisting of a methyl group, an ethyl group, a propyl group, a vinyl group, and an ethynyl group. The wetting group is advantageous for guiding lithium metal deposition and improving the uniformity of lithium metal deposition, thereby improving the coulombic efficiency and cycle characteristics of the secondary battery.

[0034] In some embodiments of the present invention, the porosity of the three-dimensional framework satisfies a porosity of ≥ 80%. For example, the porosity of the three-dimensional framework may be 80%, 84%, 86%, 88%, 90%, 92%, or a range consisting of any two values ​​therein. Adjusting the porosity of the three-dimensional framework within this range is advantageous in providing space for lithium metal deposition, thereby improving the coulombic efficiency and cycle characteristics of the secondary battery.

[0035] In some embodiments of the invention, the three-dimensional framework contains 5 mAh / cm 2 When lithium metal is deposited on the three-dimensional framework, the thickness change rate of the three-dimensional framework is less than 10%. For example, the thickness change rate of the three-dimensional framework may be 1%, 2%, 4%, 6%, 8%, 10%, or a range consisting of any two values ​​therein. This indicates that the volume of the three-dimensional framework changes little during the process of lithium deposition on the three-dimensional framework, which is advantageous for reducing the thickness expansion rate of the negative electrode piece, and indicates that the secondary battery provided by the present invention has a reduced thickness expansion rate.

[0036] In some embodiments of the present invention, the metallic lithium layer is obtained by pre-replenishing with lithium, and the present invention does not particularly limit the manner of pre-replenishing with lithium as long as the objectives of the present invention can be achieved. Exemplarily, the manner of pre-replenishing with lithium may include, but is not limited to, cold pressing, hot pressing, electrochemical lithium replenishment, or physical vapor deposition (PVD) lithium replenishment.

[0037] In the present invention, the 3D framework is prepared by suction filtration. For example, first, 0D material, 1D material, and 2D material are added to deionized water and ultrasonically dispersed until uniformly dispersed, obtaining Solution 1. Then, 1D conductive fibers are dispersed in deionized water using ultrasonic dispersion and ultrasonically dispersed until uniformly dispersed, obtaining Solution 2. Solution 1 is suction filtered using a suction filtration device. After suction filtration of Solution 1 is completed, Solution 2 is added and suction filtered. After suction filtration is completed, the mixture is dried to obtain film pieces. Optionally, the film pieces are composited with lithium metal by cold pressing to obtain negative electrode pieces. The suction filtration device and suction filtration process are all known in the art and are not limited thereto. In the present invention, the solid content of Solution 1 and Solution 2 is not particularly limited and can be selected according to actual circumstances as long as the objectives of the present invention are achieved. In the present invention, there are no particular limitations on the pressure when compounding by cold pressing, as long as the object of the present invention can be achieved. For example, the pressure when compounding by cold pressing may be 0.1 to 3 tons.

[0038] Generally, the solids content of Solution 1 can be adjusted by adjusting the volume of deionized water in Solution 1, and the thickness of the second layer skeleton can be adjusted by adjusting the solids content of Solution 1 or the amount of Solution 1 charged and the suction filtration time when suction filtering Solution 1. For example, if the volume of Solution 1 suctioned and the suction filtration time remain unchanged and the solids content of Solution 1 increases, the thickness of the second layer skeleton increases. If the volume of Solution 1 suctioned and the suction filtration time remain unchanged and the solids content of Solution 1 decreases, the thickness of the second layer skeleton decreases. If the solids content of Solution 1 suctioned and the suction filtration time remain unchanged and the volume of Solution 1 suctioned and / or the suction filtration time decreases, the thickness of the second layer skeleton increases. If the solids content of Solution 1 suctioned and the suction filtration time remain unchanged and the volume of Solution 1 suctioned and / or the suction filtration time increases, the thickness of the second layer skeleton increases. If the solids content of Solution 1 suctioned and the suction filtration time remains unchanged and the volume of Solution 1 suctioned and / or the suction filtration time increases, the thickness of the second layer skeleton decreases.

[0039] Generally, the solids content of Solution 2 can be adjusted by adjusting the volume of deionized water in Solution 2, and the thickness of the first layer skeleton can be adjusted by adjusting the solids content of Solution 2 or the amount of Solution 2 charged and the suction filtration time when suction filtering Solution 2. For example, if the volume of Solution 2 suctioned and the suction filtration time remain unchanged and the solids content of Solution 2 increases, the thickness of the first layer skeleton increases. If the volume of Solution 2 suctioned and the suction filtration time remain unchanged and the solids content of Solution 2 decreases, the thickness of the first layer skeleton decreases. If the solids content of Solution 2 suctioned and the suction filtration time remain unchanged and the volume of Solution 2 suctioned and / or the suction filtration time decreases, the thickness of the first layer skeleton increases. If the solids content of Solution 2 suctioned and the suction filtration time remain unchanged and the volume of Solution 2 suctioned and / or the suction filtration time increases, the thickness of the first layer skeleton increases. If the solids content of Solution 2 suctioned and the suction filtration time remains unchanged and the volume of Solution 2 suctioned and / or the suction filtration time increases, the thickness of the first layer skeleton decreases.

[0040] The thickness of the three-dimensional skeleton increases as the thickness of the first layer skeleton and / or the thickness of the second layer skeleton increases, and decreases as the thickness of the first layer skeleton and / or the thickness of the second layer skeleton decreases.

[0041] In the present invention, the zero-dimensional materials with different particle sizes and the one-dimensional materials with different diameter-to-major axis ratios are all obtained by purchasing, and in the present invention, there are no particular restrictions on their origins, as long as the object of the present invention can be achieved.

[0042] The secondary battery of the present invention is not particularly limited and may include a device in which an electrochemical reaction occurs. For example, the secondary battery may include, but is not limited to, a lithium metal secondary battery, a lithium ion secondary battery, a sodium ion secondary battery, a lithium polymer secondary battery, or a lithium ion polymer secondary battery.

[0043] The secondary battery of the present invention may include a positive electrode piece. However, the present invention is not particularly limited to the positive electrode piece, as long as the objectives of the present invention are achieved. For example, the positive electrode piece typically includes a positive electrode current collector and a positive electrode material layer. The positive electrode material layer may be provided on one surface of the positive electrode current collector in the thickness direction, or on both surfaces of the positive electrode current collector in the thickness direction. Note that the "surface" may be the entire area of ​​the positive electrode current collector or a portion of the area of ​​the positive electrode current collector. In the present invention, the positive electrode current collector is not particularly limited, as long as the objectives of the present invention are achieved. For example, the positive electrode current collector may include, but is not limited to, aluminum foil, aluminum alloy foil, or a composite current collector (e.g., an aluminum-carbon composite current collector). In the present invention, the thickness of the positive electrode current collector is not particularly limited, as long as the objectives of the present invention are achieved. For example, the thickness is 8 μm to 20 μm.

[0044] In the present invention, the positive electrode layer includes a positive electrode material. The positive electrode material is not particularly limited as long as it achieves the object of the present invention, and may include, for example, at least one of lithium and a composite oxide of a transition metal element. The transition metal element is not particularly limited as long as it achieves the object of the present invention, and may include, for example, at least one of nickel, manganese, cobalt, and iron. Specifically, the positive electrode material may include at least one of lithium nickel cobalt manganese oxide, lithium nickel cobalt aluminate, lithium iron phosphate, lithium-rich manganese material, lithium cobalt oxide, lithium manganese oxide, lithium iron manganese phosphate, and lithium titanate.

[0045] In the present invention, the positive electrode material layer may include a positive electrode conductive agent. The positive electrode conductive agent is not particularly limited as long as it can achieve the objectives of the present invention. For example, the positive electrode conductive agent may include at least one of conductive carbon black (Super P), carbon nanotubes (CNTs), carbon fiber, acetylene black, flake graphite, Ketjen black, graphene, a metal material, and a conductive polymer, but is not limited to these. The carbon nanotubes may include, but are not limited to, single-walled carbon nanotubes and / or multi-walled carbon nanotubes. The carbon fiber may include, but is not limited to, vapor-grown carbon fiber (VGCF) and / or carbon nanofibers. The metal material may include, but is not limited to, metal powder and / or metal fiber. Specifically, the metal may include, but is not limited to, at least one of copper, nickel, aluminum, and silver. The conductive polymer may include, but is not limited to, at least one of polyphenylene derivatives, polyaniline, polythiophene, polyacetylene, and polypyrrole. In the present invention, the positive electrode material layer may contain a positive electrode binder. In the present invention, there are no particular limitations on the positive electrode binder as long as the object of the present invention can be achieved. For example, the positive electrode binder may contain at least one of polyacrylic acid, sodium polyacrylate, potassium polyacrylate, lithium polyacrylate, polyimide, polyvinyl alcohol, carboxymethyl cellulose, sodium carboxymethyl cellulose, lithium carboxymethyl cellulose, polyamide imide, styrene butadiene rubber, and polyvinylidene fluoride, but is not limited to these.

[0046] Optionally, the positive electrode piece may include a conductive layer, which is located between the positive electrode current collector and the positive electrode material layer. In the present invention, the composition of the conductive layer is not particularly limited, and may be a conductive layer commonly used in the art, for example, but not limited to, the positive electrode conductive agent and the positive electrode binder.

[0047] The secondary battery of the present invention further includes a separator. The separator is not particularly limited in the present invention and can be selected by those skilled in the art based on their practical needs, as long as the objectives of the present invention can be achieved. For example, the separator material may include, but is not limited to, at least one of polyolefins (PO) mainly consisting of polyethylene (PE) and polypropylene (PP), polyester (e.g., polyethylene terephthalate (PET)), cellulose, polyimide (PI), polyamide (PA), spandex, and aramid. The separator type may include, but is not limited to, at least one of woven membranes, nonwoven membranes, microporous membranes, composite membranes, separator paper, rolled membranes, and spun membranes. For example, the separator may include a substrate layer and a surface treatment layer. The substrate layer may be a nonwoven fabric, membrane, or composite membrane having a porous structure, and the substrate layer material may include at least one of polyethylene, polypropylene, polyethylene terephthalate, polyimide, etc. Optionally, a polypropylene porous membrane, a polyethylene porous membrane, a polypropylene nonwoven fabric, a polyethylene nonwoven fabric, or a polypropylene-polyethylene-polypropylene porous composite membrane may be used. Optionally, a surface treatment layer is provided on at least one surface of the substrate layer. The surface treatment layer may be a polymer layer, an inorganic layer, or a layer formed by mixing a polymer and an inorganic material. For example, the inorganic layer may contain inorganic particles and a binder. The inorganic particles are not particularly limited and may include at least one of alumina, silicon oxide, magnesium oxide, titanium oxide, hafnium dioxide, tin oxide, cerium oxide, nickel oxide, zinc oxide, calcium oxide, zirconium oxide, yttrium oxide, silicon carbide, boehmite, aluminum hydroxide, magnesium hydroxide, calcium hydroxide, and barium sulfate.The binder is not particularly limited and may include, for example, at least one of polyvinylidene fluoride, a copolymer of vinylidene fluoride and hexafluoropropylene, polyamide, polyacrylonitrile, polyacrylic acid ester, polyacrylic acid, polyacrylate, polyvinylpyrrolidone, polyvinyl ether, polymethyl methacrylate, polytetrafluoroethylene, and polyhexafluoropropylene. The polymer layer includes a polymer, and the polymer material includes at least one of polyamide, polyacrylonitrile, an acrylic acid ester polymer, polyacrylic acid, polyacrylate, polyvinylpyrrolidone, polyvinyl ether, polyvinylidene fluoride, and poly(vinylidene fluoride-hexafluoropropylene).

[0048] The secondary battery of the present invention further includes an electrolyte. The electrolyte is not particularly limited and can be selected by those skilled in the art based on their practical needs, as long as the objectives of the present invention are achieved. For example, the electrolyte includes an organic solvent and a lithium salt. The types and contents of the organic solvent and the lithium salt are not particularly limited and can be selected as long as the objectives of the present invention are achieved. For example, the organic solvent may include, but is not limited to, at least one of a carbonate ester compound, a carboxylic acid ester compound, an ether compound, and other organic solvents. The carbonate ester compound may include, but is not limited to, at least one of a chain carbonate ester compound, a cyclic carbonate ester compound, and a fluorocarbonate ester compound. The chain carbonate ester compound may include, but is not limited to, at least one of dimethyl carbonate (DMC), diethyl carbonate (DEC), dipropyl carbonate (DPC), methyl propyl carbonate (MPC), ethyl propyl carbonate (EPC), and ethyl methyl carbonate (EMC). The cyclic carbonate ester may include, but is not limited to, at least one of ethylene carbonate (EC), propylene carbonate (PC), butylene carbonate (BC), and vinyl ethylene carbonate (VEC). The fluorocarbonate ester compound may include, but is not limited to, at least one of fluoroethylene carbonate (FEC), 1,2-difluoroethylene carbonate, 1-difluoroethylene carbonate, 1,1,2-trifluoroethylene carbonate, 1,1,2,2-tetrafluoroethylene carbonate, fluoro-2-methylethylene carbonate, fluoro-methylethylene carbonate, 1,2-difluoro-methylethylene carbonate, 1,1,2-trifluoro-2-methylethylene carbonate, and trifluoromethylethylene carbonate. The carboxylic acid ester compound may include, but is not limited to, at least one of methyl formate, methyl acetate, ethyl acetate, n-propyl acetate, tert-butyl acetate, methyl propionate, ethyl propionate, propyl propionate, γ-butyrolactone, decalactone, valerolactone, and caprolactone.The ether compound may include, but is not limited to, at least one of dibutyl ether, tetraethylene glycol dimethyl ether, diethylene glycol dimethyl ether, 1,2-dimethoxyethane, 1,2-diethoxyethane, acetaldehyde ethyl methyl acetal, 2-methyltetrahydrofuran, and tetrahydrofuran. The other organic solvent may include, but is not limited to, at least one of dimethyl sulfoxide, 1,2-dioxolane, sulfolane, methyl sulfolane, 1,3-dimethyl-2-imidazolidone, N-methyl-2-pyrrolidone, dimethylformamide, acetonitrile, trimethyl phosphate, triethyl phosphate, and trioctyl phosphate. Exemplarily, the lithium salt may include at least one of LiTFSI, LiPF, LiBF, LiAsF, LiClO, LiB(C H ), LiCH SO, LiCF SO, LiC(SO CF), LiSiF, lithium bis(oxalato)borate (LiBOB), and lithium difluoroborate, but is not limited to these.

[0049] The process for preparing the secondary battery of the present invention is well known to those skilled in the art and is not particularly limited in the present invention. For example, the process may include, but is not limited to, stacking a positive electrode piece, a separator, and a negative electrode piece in order, and optionally rolling or folding the stack to obtain a wound electrode assembly, placing the electrode assembly in a packaging bag, injecting an electrolyte into the packaging bag, and sealing the packaging bag to obtain a secondary battery; or stacking a positive electrode piece, a separator, and a negative electrode piece in order, securing the four corners of the entire stack with tape to obtain a stacked electrode assembly, placing the electrode assembly in a packaging bag, injecting an electrolyte into the packaging bag, and sealing the packaging bag to obtain a secondary battery. Furthermore, to prevent internal pressure buildup and overcharging and discharging of the secondary battery, an overcurrent protection element, lead plates, etc. may be provided in the packaging bag as needed. Here, the packaging bag is a packaging bag known in the art, and therefore the present invention is not limited thereto.

[0050] A second aspect of the present invention provides an electronic device including the secondary battery described in the above embodiment. The electronic device is not particularly limited and may be any known electronic device used in the prior art. For example, the electronic device may include, but is not limited to, laptop computers, pen-input computers, mobile computers, electronic book players, mobile phones, portable facsimiles, portable copiers, portable printers, stereo headsets, video recorders, LCD televisions, portable vacuum cleaners, portable CD players, mini CDs, walkie-talkies, electronic notebooks, calculators, memory cards, portable tape recorders, radios, backup power supplies, motors, automobiles, motorcycles, auxiliary bicycles, bicycles, lighting equipment, toys, game consoles, watches, power tools, flashlights, cameras, large household storage batteries, and lithium-ion capacitors.

[0051] Example Hereinafter, the embodiments of the present invention will be described in more detail with reference to Examples and Comparative Examples. Various tests and evaluations were carried out according to the following methods.

[0052] Measurement methods and equipment: Coulombic efficiency measurement: The lithium metal battery was placed in a thermostatic chamber at 20°C and allowed to stand for 30 minutes to allow the battery to reach a constant temperature. The lithium metal battery was charged at a constant current of 0.2C until the voltage reached 3.7V, then charged at a constant voltage of 0.025C at 3.7V, allowed to stand for 5 minutes, and then discharged at a constant current of 0.2C until the voltage reached 2.8V, and allowed to stand for 5 minutes. This constituted one cycle. The capacity of the initial discharge was defined as 100%, and the charge-discharge cycle was repeated until the electrical capacity had decayed to 80%. The measurement was then stopped, and the average ratio of the discharge capacity to the charge capacity for each cycle was calculated as the Coulombic efficiency.

[0053] Measurement of cycle characteristics: The lithium metal battery was placed in a thermostatic chamber at 25°C ± 2°C and allowed to stand for two hours to allow the lithium-ion battery to reach a constant temperature. For cycle process 1, the lithium metal battery was charged at a constant current of 0.2 C until the voltage reached 3.7 V, then charged at a constant voltage of 0.5 C at 3.7 V, allowed to stand for five minutes, and then discharged at a constant current of 1 C until the voltage reached 2.8 V. This constituted one charge-discharge cycle. The discharge capacity of the lithium metal battery was recorded after the first cycle, and then the charge-discharge cycle was repeated according to cycle process 1, with the discharge capacity recorded after each cycle. At the 50th, 100th, 150th, 200th, and 250th cycles, a charge-discharge cycle was performed according to cycle process 2. For cycle process 2, one charge-discharge cycle consisted of charging at a constant current of 0.05 C until the voltage reached 3.7 V, then charging at a constant voltage of 0.025 C at 3.7 V, leaving the battery standing for 5 minutes, and then discharging at a constant current of 0.05 C until the voltage reached 2.8 V. The discharge capacity after each cycle was recorded.

[0054] Lithium metal battery cycle capacity retention rate = discharge capacity after each cycle / discharge capacity after the first cycle × 100%.

[0055] When the cycle capacity retention rate of the lithium metal battery reached 80%, the number of cycles at that time was recorded. In the examples and comparative examples, 10 lithium metal batteries were measured, and the average number of cycles was used as the final result.

[0056] Porosity measurement: The three-dimensional scaffolds prepared in the examples and comparative examples were cut into round sheets with a diameter of 10 mm, and the surfaces of the round sheets were flat without chips. The true volume V1 of the round sheets was obtained using a true density tester, and the apparent volume V2 = S × H (S is the surface area of ​​the sample, and H is the thickness of the sample), and the porosity = (V2 - V1)V2 × 100%.

[0057] In this measurement method, the true volume was defined as the volume of the sample excluding pores, and the porosity was defined as the ratio of the pore volume of the sample to the apparent volume of the sample. The porosity reflects the number of voids in the sample, which has an important effect on ion transport in lithium metal batteries.

[0058] Scanning electron microscope measurements: Measurements were made using a Philips XL-30 field emission scanning electron microscope.

[0059] Measurement of 3D skeleton, 1st layer skeleton, and 2nd layer skeleton thickness: Solution 1 was filtered by suction using a suction filtration device. After suction filtration of Solution 1 was completed, Solution 2 was added and filtered by suction. After suction filtration was completed, the solution was dried to obtain a film piece. The thickness of the film piece was measured with a micrometer and labeled H0. Solution 1 was filtered by suction using a suction filtration device. After suction filtration was completed, the solution was dried to obtain a film piece. The thickness of the film piece 1 was measured with a micrometer and labeled H1. The thickness of the three-dimensional skeleton was H0, the thickness of the first layer skeleton was H0-H1, and the thickness of the second layer skeleton was H1. Here, Solution 1 and Solution 2 were Solution 1 and Solution 2 in each Example or Comparative Example.

[0060] Thickness change measurement: The prepared three-dimensional scaffold was cut to obtain a cross section, and a Philips XL-30 field emission scanning electron microscope was used to photograph the cross section of the three-dimensional scaffold. The scanning electron micrograph of the cross section of the three-dimensional scaffold was obtained and imported into Nano Measurer software to measure the thickness of the three-dimensional scaffold, which was designated as H2.

[0061] Lithium metal deposition rate of 5mAh / cm 2 The lithium metal battery in each example or comparative example was set to 0.2 mA / cm 2The lithium metal battery was disassembled, the pole pieces were washed with DME, and cross sections were cut out. The cross sections of the three-dimensional skeletons in the pole pieces were photographed using a Philips XL-30 field emission scanning electron microscope. The scanning electron micrographs of the cross sections of the three-dimensional skeletons in the pole pieces were then imported into Nano Measurer software, and the thickness of the three-dimensional skeletons in the pole pieces was measured and recorded as H3. Here, T0 in Examples 1 to 24 and Comparative Examples 1 to 10 was 25 hours. Thickness change rate = (H3-H2) / H2 x 100%.

[0062] Conductivity measurement: Measurements were carried out in accordance with the Chinese national standard "Conductivity Meter Test Method" (GB11007-89).

[0063] Example 1 <Preparation of negative electrode pieces> m1 = 7 mg of multi-walled carbon nanotubes (manufacturer: Shanghai Aladdin Biochemical Technology Co., Ltd., model number: 308068-56-6), a one-dimensional material, and m2 = 1 mg of MXene (manufacturer: Nanjing Xianfeng Nanomaterial Technology Ltd., model number: 12363-89-2), a two-dimensional material, were added to 100 mL of deionized water and thoroughly ultrasonically dispersed. m0 = 0.16 mg of tin dioxide particles, a zero-dimensional material, were added and ultrasonically dispersed until uniformly dispersed, obtaining Solution 1. The particle diameter of the zero-dimensional material was 0.3 μm, and the one-dimensional material had a diameter of 2 nm and an aspect ratio of 10,000. It was 12,000.

[0064] 1 mg of multi-walled carbon nanotubes (manufacturer: Shanghai Aladdin Biochemical Technology Co., model: 308068-56-6), which are one-dimensional conductive fibers, was dispersed in 20 mL of deionized water using ultrasonic waves until uniformly dispersed, to obtain solution 2.

[0065] A1 = 100 mL of Solution 1 was added using a vacuum filtration device and vacuum filtered for t1 = 180 minutes. After vacuum filtration of Solution 1 was completed, A2 = 20 mL of Solution 2 was added and vacuum filtered for t2 = 30 minutes. After vacuum filtration was completed, the film was placed in an 80 °C oven and dried for 24 hours to obtain a film. The film was then combined with 20 μm of lithium metal by cold pressing to obtain a negative electrode. Here, the first layer skeleton was 5 μm thick, the second layer skeleton was 50 μm thick, and the three-dimensional skeleton was 55 μm thick. The cold pressing pressure was 0.2 T. The negative electrode was then punched into a round sheet with a diameter of 18 mm.

[0066] <Preparation of positive electrode piece> The positive electrode active materials, lithium iron phosphate (LiFePO4), conductive carbon black (Super P), and polyvinylidene fluoride (PVDF), were mixed in a weight ratio of 97.5:1.0:1.5, and N-methylpyrrolidone (NMP) was added as a solvent to prepare a slurry with a solids content of 75 wt%. The slurry was then uniformly mixed. The slurry was uniformly applied to one surface of a 10 μm-thick aluminum foil positive electrode current collector and dried at 90°C to obtain a positive electrode piece coated with a positive electrode material layer on one side. The positive electrode material layer was 50 μm thick. The same process was then repeated on the other surface of the positive electrode piece, resulting in a positive electrode piece coated with a positive electrode material layer on both sides. The positive electrode piece was then cold-pressed and punched into a round sheet with a diameter of 14 mm.

[0067] <Preparation of electrolyte> In a dry argon atmosphere, dioxolane (DOL) and dimethyl ether (DME) were mixed in a volume ratio of DOL:DME = 1:1 to obtain an organic solvent, and then lithium salt LiTFSI was added to the organic solvent, dissolved, and mixed uniformly to obtain an electrolyte solution with a lithium salt concentration of 1 mol / L.

[0068] <Separator> A 15 μm thick polyethylene (PE) film (provided by Celgard) was used.

[0069] <Preparation of Lithium Metal Batteries> In a vacuum glove box, the open side of the positive electrode case of the button battery case was placed facing up, and the gasket and the prepared positive electrode pieces were placed in that order. An electrolyte was dripped onto the surface of the positive electrode piece, and then the separator was placed on top of the positive electrode piece. After the surface of the separator was wetted with the electrolyte, the prepared negative electrode piece, the gasket, and the elastic sheet were placed on top of the separator in that order. The negative electrode case of the button battery case was then covered, and the resulting product was sealed and pressed using a sealing machine to obtain a button battery. The gasket and elastic sheet can be purchased, but the present invention is not limited thereto.

[0070] Example 2 When preparing the negative electrode pieces, the mass m1 of the multi-walled carbon nanotubes, which are the one-dimensional material in solution 1, was 10.5 mg, the mass m2 of the two-dimensional material MXene was 1.5 mg, the mass m0 of the tin dioxide particles, which are the zero-dimensional material, was 0.24 mg, the volume of deionized water was 150 mL, the mass of the multi-walled carbon nanotubes, which are the one-dimensional conductive fibers in solution 2, was 1.5 mg, and the volume of deionized water was 30 mL. When suction filtration was performed, the amount A1 of solution 1 was 150 mL, the suction filtration time t1 was 288 minutes, the amount A2 of solution 2 was 20 mL, and the diameter and aspect ratio of the one-dimensional material were adjusted according to Table 1, except as in Example 1.

[0071] Example 3 When preparing the negative electrode pieces, the mass m1 of the multi-walled carbon nanotubes, which are the one-dimensional material in solution 1, was 14 mg, the mass m2 of the two-dimensional material MXene was 2 mg, the mass m0 of the tin dioxide particles, which are the zero-dimensional material, was 0.32 mg, the volume of deionized water was 200 mL, the mass of the multi-walled carbon nanotubes, which are the one-dimensional conductive fibers in solution 2, was 2 mg, and the volume of deionized water was 40 mL. When suction filtration was performed, the amount A1 of solution 1 was 200 mL, the suction filtration time t1 was 360 minutes, the amount A2 of solution 2 was 20 mL, and the diameter and aspect ratio of the one-dimensional material were adjusted according to Table 1, except that the same procedure as in Example 1 was performed.

[0072] Example 4 When preparing the negative electrode pieces, the procedure was the same as in Example 1, except that the amount A1 of solution 1 used in suction filtration was 20 mL, the suction filtration time t1 was 36 minutes, and the diameter and aspect ratio of the one-dimensional material were adjusted according to Table 1.

[0073] Example 5 When preparing the negative electrode pieces, the mass m1 of the multi-walled carbon nanotubes (1D material) in Solution 1 was 28 mg, the mass m2 of the 2D material MXene was 4 mg, the mass m0 of the tin dioxide particles (0D material) was 0.64 mg, the volume of deionized water was 400 mL, when suction filtering was performed, only Solution 1 was suction filtered and Solution 2 was not suction filtered, the amount A1 of Solution 1 was 400 mL, the suction filtering time t1 was 720 minutes, and the diameter and aspect ratio of the 1D material were adjusted according to Table 1, except for the same as in Example 1.

[0074] Example 6 When preparing the negative electrode pieces, the mass m1 of the multi-walled carbon nanotubes (1D material) in Solution 1 was 14 mg, the mass m2 of the 2D material MXene was 2 mg, and the mass m0 of the tin dioxide particles (0D material) was 0.32 mg. The volume of deionized water was 200 mL. When performing suction filtration, the amount A1 of Solution 1 was 108 mL, the suction filtration time t1 was 200 minutes, the amount A2 of Solution 2 was 4 mL, the suction filtration time t2 was 10 minutes, and the diameter and aspect ratio of the 1D material were adjusted according to Table 1. The procedure was the same as in Example 1.

[0075] Example 7 When preparing the negative electrode pieces, the mass m1 of the multi-walled carbon nanotubes (1D material) in Solution 1 was 14 mg, the mass m2 of the 2D material MXene was 2 mg, and the mass m0 of the tin dioxide particles (0D material) was 0.32 mg. The volume of deionized water was 200 mL. When performing suction filtration, the amount A1 of Solution 1 was 104 mL, the suction filtration time t1 was 188 minutes, the amount A2 of Solution 2 was 12 mL, the suction filtration time t2 was 18 minutes, and the diameter and aspect ratio of the 1D material were adjusted according to Table 1. The procedure was the same as in Example 1.

[0076] Example 8 When preparing the negative electrode pieces, the mass of the multi-walled carbon nanotubes, which are one-dimensional conductive fibers, in solution 2 was 2 mg, the volume of deionized water was 40 mL, and when suction filtration was performed, the amount A1 of solution 1 was 80 mL, the suction filtration time t1 was 168 minutes, the amount A2 of solution 2 was 40 mL, the suction filtration time t2 was 60 minutes, and the diameter and aspect ratio of the one-dimensional material were adjusted according to Table 1, except that the procedure was the same as in Example 1.

[0077] Example 9 When preparing the negative electrode pieces, the mass m1 of the multi-walled carbon nanotubes (1D material) in Solution 1 was 16 mg, the mass m2 of the 2D material MXene was 2 mg, the mass m0 of the tin dioxide particles (0D material) was 0.36 mg, the volume of deionized water was 200 mL, when suction filtration was performed, the amount A1 of Solution 1 was 115 mL, the suction filtration time t1 was 198 minutes, no Solution 2 was added, and the diameter and aspect ratio of the 1D material were adjusted according to Table 1, except as in Example 1.

[0078] Example 10 When preparing the negative electrode pieces, the mass m0 of the tin dioxide particles, which is the zero-dimensional material in solution 1, was 0.08 mg; when suction filtering was performed, the suction filtering time t1 of solution 1 was 180 minutes; and the diameter and aspect ratio of the one-dimensional material were adjusted according to Table 1, which was the same as in Example 1.

[0079] Example 11 When preparing the negative electrode pieces, the mass m0 of the tin dioxide particles, which is the zero-dimensional material in solution 1, was 0.4 mg; when suction filtering was performed, the suction filtering time t1 of solution 1 was 180 minutes; and the diameter and aspect ratio of the one-dimensional material were adjusted according to Table 1, which was the same as in Example 1.

[0080] Example 12 When preparing the negative electrode pieces, the mass m0 of the tin dioxide particles, which is the zero-dimensional material in solution 1, was 0.8 mg, and when suction filtering was performed, the suction filtering time t1 of solution 1 was 180 minutes, and the aspect ratio of the one-dimensional material was adjusted according to Table 1, except that the procedure was the same as in Example 1.

[0081] Example 13 When preparing the negative electrode pieces, the mass m0 of the tin dioxide particles, which is the zero-dimensional material in solution 1, was 2.7 mg, and when suction filtering was performed, the suction filtering time t1 of solution 1 was 180 minutes, except that the procedure was the same as in Example 1.

[0082] Example 14 The negative electrode pieces were prepared in the same manner as in Example 1, except that the mass m1 of the multi-walled carbon nanotube, which is the one-dimensional material in Solution 1, was 7.57 mg, the mass m2 of the MXene, which is the two-dimensional material, was 0.43 mg, and the diameter and aspect ratio of the one-dimensional material were adjusted according to Table 1.

[0083] Example 15 When preparing the negative electrode pieces, the mass m1 of the multi-walled carbon nanotube, which is the one-dimensional material in Solution 1, was 2 mg, the mass m2 of the MXene, which is the two-dimensional material, was 6 mg, and the diameter and aspect ratio of the one-dimensional material were adjusted according to Table 1, except that the procedure was the same as in Example 1.

[0084] Example 16 When preparing the negative electrode pieces, the mass m1 of the multi-walled carbon nanotube, which is the one-dimensional material in Solution 1, was 1 mg, the mass m2 of the MXene, which is the two-dimensional material, was 7 mg, and the diameter and aspect ratio of the one-dimensional material were adjusted according to Table 1, except that the procedure was the same as in Example 1.

[0085] Example 17 The negative electrode pieces were prepared in the same manner as in Example 1, except that the one-dimensional material in solution 1 and the one-dimensional conductive fiber in solution 2 were both carbon nanofibers (manufacturer: Nanjing Xianfeng Nanomaterial Technology Ltd., model: 1333-86-4), and the diameter and aspect ratio of the one-dimensional material were adjusted according to Table 1.

[0086] Example 18 The negative electrode pieces were prepared in the same manner as in Example 1, except that graphene (manufacturer: Nanjing Xianfeng Nanomaterial Technology Ltd., model: 7440-44-0) was used as the two-dimensional material in Solution 1, and the diameter and aspect ratio of the one-dimensional material were adjusted according to Table 1.

[0087] Example 19 The preparation of the negative electrode pieces was the same as in Example 1, except that SiO2 was used as the zero-dimensional material in Solution 1, and the diameter and aspect ratio of the one-dimensional material were adjusted according to Table 1.

[0088] Example 20 The preparation of the negative electrode pieces was the same as in Example 1, except that TiO2 was used as the zero-dimensional material in Solution 1, and the diameter and aspect ratio of the one-dimensional material were adjusted according to Table 1.

[0089] Example 21 When preparing the negative electrode pieces, Ag powder (manufacturer: Shanghai Aladdin Biochemical Technology Co., model: 7440-22-4) was used as the zero-dimensional material in solution 1, and the particle diameter of the Ag powder was 0.1 μm to 1 μm. The diameter and aspect ratio of the one-dimensional material were adjusted according to Table 1, except that the procedure was the same as in Example 1.

[0090] Examples 22 to 24 The negative electrode pieces were prepared in the same manner as in Example 1, except that after the film pieces were dried, they were further subjected to a roller cold press treatment, and the diameter and aspect ratio of the one-dimensional material were adjusted according to Table 1. The pressures of the roller cold press treatment were 0.8t, 1.2t, and 1.5t, respectively.

[0091] Example 25 <Preparation of modified Fe6N3> The Fe6N3 was sintered at 500°C for 2 hours in an NH3 atmosphere to obtain Fe6N3 containing -NH2 wettable groups on the surface, i.e., modified Fe6N3.

[0092] When preparing the negative electrode piece, the same procedure as in Example 1 was carried out, except that modified Fe6N3 was used as the zero-dimensional material in solution 1, and the diameter and aspect ratio of the one-dimensional material were adjusted according to Table 1.

[0093] Comparative Example 1 When preparing the negative electrode pieces, only 10 mg of one-dimensional material, multi-walled carbon nanotubes, was added to solution 1, and when suction filtering was performed, only solution 1 was suction filtered and solution 2 was not suction filtered. The amount A1 of solution 1 was 100 mL, the suction filtering time t1 was 198 minutes, and the diameter and aspect ratio of the one-dimensional material were adjusted according to Table 1, except that the procedure was the same as in Example 1.

[0094] Comparative Example 2 When preparing the negative electrode pieces, only multi-walled carbon nanotubes, which are one-dimensional materials, with m1 of 10 mg, and tin dioxide particles, which are zero-dimensional materials, with m0 of 0.2 mg, are added to solution 1, and when suction filtering is performed, only solution 1 is suction filtered and solution 2 is not suction filtered. The amount A1 of solution 1 is 100 mL, the suction filtering time t1 is 198 minutes, and the diameter and aspect ratio of the one-dimensional material are adjusted according to Table 1, except that the same as in Example 1.

[0095] Comparative Example 3 When preparing the negative electrode pieces, only 10 mg of the two-dimensional material MXene was added to solution 1, and when suction filtering was performed, only solution 1 was suction filtered and solution 2 was not suction filtered. The amount A1 of solution 1 was 100 mL, and the suction filtering time t1 was 198 minutes, all except for the same procedure as in Example 1.

[0096] Comparative Example 4 The negative electrode piece was the same as in Example 1, except that a commercially available 50 μm lithium-copper composite tape pre-replenished with lithium was used.

[0097] Comparative Example 5 When preparing the negative electrode pieces, the mass m1 of the multi-walled carbon nanotubes (1D material) in Solution 1 was 4.61 mg, the mass m2 of the MXene (2D material) was 0.66 mg, and the mass m0 of the tin dioxide particles (0D material) was 2.89 mg. The diameter and aspect ratio of the 1D material were adjusted according to Table 1, but the procedure was the same as in Example 1.

[0098] Comparative Example 6 When preparing the negative electrode pieces, the mass m1 of the multi-walled carbon nanotubes, which are one-dimensional materials, in Solution 1 was 7.69 mg, the mass m2 of the MXene, which are two-dimensional materials, was 0.31 mg, and the mass m0 of the tin dioxide particles, which are zero-dimensional materials, was 0.16 mg. The diameter and aspect ratio of the one-dimensional materials were adjusted according to Table 1, but the process was the same as in Example 1.

[0099] Comparative Example 7 When suction filtration was performed, the amount A1 of solution 1 was 10 mL, the suction filtration time t1 was 180 minutes, and the diameter and aspect ratio of the one-dimensional material were adjusted according to Table 1, except that the procedure was the same as in Example 1.

[0100] Comparative Example 8 When preparing the negative electrode pieces, the mass m1 of the multi-walled carbon nanotubes (1D material) in Solution 1 was 35 mg, the mass m2 of the 2D material MXene was 5 mg, the mass m0 of the tin dioxide particles (0D material) was 0.8 mg, the volume of deionized water was 500 mL, and when suction filtration was performed, the amount A1 of Solution 1 was 500 mL, the suction filtration time t1 was 180 minutes, and the diameter and aspect ratio of the 1D material were adjusted according to Table 1, except as in Example 1.

[0101] Comparative Example 9 When preparing the negative electrode pieces, the mass m1 of the multi-walled carbon nanotubes (1D material) in Solution 1 was 23.2 mg, the mass m2 of the 2D material MXene was 3.32 mg, the mass m0 of the tin dioxide particles (0D material) was 14.28 mg, the volume of deionized water was 500 mL, and when suction filtration was performed, the amount A1 of Solution 1 was 500 mL, the suction filtration time t1 was 180 minutes, and the diameter and aspect ratio of the 1D material were adjusted according to Table 1, except as in Example 1.

[0102] Comparative Example 10 When preparing the negative electrode pieces, the mass m1 of the multi-walled carbon nanotubes (1D material) in Solution 1 was 25.5 mg, the mass m2 of the 2D material MXene was 1.02 mg, the mass m0 of the tin dioxide particles (0D material) was 14.28 mg, the volume of deionized water was 500 mL, and when suction filtration was performed, the amount A1 of Solution 1 was 500 mL, the suction filtration time t1 was 180 minutes, and the diameter and aspect ratio of the 1D material were adjusted according to Table 1, except as in Example 1.

[0103] The preparation parameters and performance measurements for each example and comparative example are shown in Table 1.

[0104] [Table 1]

[0105] [Table 2]

[0106] As can be seen from Examples 1 to 25 and Comparative Examples 1 to 10, the lithium metal batteries using the 3D frameworks prepared in the examples of the present invention have higher coulombic efficiency and a longer cycle life, indicating that the lithium metal batteries in the examples of the present invention have higher coulombic efficiency and better cycle characteristics. At the same time, the expansion characteristics of the lithium metal batteries are also improved due to the low thickness change rate of the 3D frameworks.

[0107] Specifically, Figure 2 is a scanning electron microscope photograph of the three-dimensional skeleton of Example 1. As can be seen from the drawing, the three-dimensional skeleton has a three-dimensional structure and voids exist in the three-dimensional skeleton. Figure 3 shows the capacity decay curves of the lithium metal batteries of Example 1 and Comparative Example 4. As can be seen from the drawing, the lithium metal battery of Comparative Example 4 had a capacity retention rate of 80% after 24 cycles, while the lithium metal battery of Example 1 maintained a capacity retention rate of approximately 90% or more after 250 cycles, indicating that the lithium metal battery provided by the present invention has better cycle characteristics.

[0108] As can be seen from Example 1 and Comparative Examples 1 to 4, when the second layer framework simultaneously contains zero-dimensional materials, one-dimensional materials, and two-dimensional materials, the lithium metal battery has higher coulombic efficiency and better cycle characteristics.

[0109] As can be seen from Example 1, Examples 10 to 13, and Comparative Example 5, when the mass percentage of the zero-dimensional material is within the range of the present invention, the lithium metal battery has higher coulombic efficiency and better cycle characteristics.

[0110] As can be seen from Example 1, Examples 14 to 16, and Comparative Example 6, when the mass ratio of the one-dimensional material to the two-dimensional material is within the range of the present invention, the lithium metal battery has higher coulombic efficiency and better cycle characteristics.

[0111] As can be seen from Example 1, Comparative Example 7, and Comparative Example 8, when the thickness of the second layer framework and the three-dimensional framework are within the range of the present invention, the lithium metal battery has higher coulombic efficiency and better cycle characteristics.

[0112] As can be seen from Example 1, Comparative Example 9, and Comparative Example 10, when the thickness of the three-dimensional framework, the thickness of the first layer framework, the thickness of the second layer framework, the mass percentage of the zero-dimensional material, and the mass ratio of the one-dimensional material to the two-dimensional material are all within the ranges of the present invention, the lithium metal battery has higher coulombic efficiency and better cycle characteristics.

[0113] The thickness of the first layer skeleton generally affects the performance of a lithium metal battery. As can be seen from Examples 1, 6 to 9, when the thickness of the first layer skeleton is within the range of the present invention, the lithium metal battery has high coulombic efficiency and good cycle characteristics.

[0114] The type of 1D conductive fiber used in the first layer skeleton and the types of 1D, 2D, and 0D materials used in the second layer skeleton generally affect the performance of lithium metal batteries. As can be seen from Examples 1, 17-21, and 25, when the type of 1D conductive fiber used in the first layer skeleton and the types of 1D, 2D, and 0D materials used in the second layer skeleton are within the ranges of the present invention, the lithium metal battery exhibits high Coulombic efficiency and good cycle characteristics. As can be seen from Examples 1-25, when the thickness of the 3D skeleton, the thickness of the first layer skeleton, the thickness of the second layer skeleton, the mass percentage of the 0D material, and the mass ratio of the 1D material to the 2D material are all within the ranges of the present invention, the 3D skeleton exhibits high porosity and low thickness change, and the 1D and 2D materials exhibit high electrical conductivity, resulting in a lithium metal battery exhibiting high Coulombic efficiency and good cycle characteristics.

[0115] The particle size of the zero-dimensional material and the diameter and aspect ratio of the one-dimensional material generally affect the performance of lithium metal batteries. As can be seen from Examples 1 to 25, when the particle size of the zero-dimensional material and the diameter and aspect ratio of the one-dimensional material are within the ranges of the present invention, the lithium metal battery has high coulombic efficiency and good cycle characteristics.

[0116] It should be noted that, in this specification, relational terms such as "first," "second," etc. are used only to distinguish one entity or operation from another, and do not necessarily require or imply that any actual relationship or ordering exists between those entities or operations. And, the term "comprises," or any other variation thereof, is intended to include non-exclusive elements, such that a process, method, article, or apparatus comprising a set of elements not only includes those elements, but also includes other elements not expressly listed or elements inherent in such process, method, article, or apparatus.

[0117] Each embodiment in this specification is described in a related manner, and the same and similar parts between the embodiments may be referred to each other, and each embodiment will be described with an emphasis on the differences from other embodiments.

[0118] The above is merely a preferred embodiment of the present invention, and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent replacements, improvements, etc. made without departing from the spirit and principles of the present invention are all included in the scope of protection of the present invention.

Claims

1. a negative electrode piece and a separator; The negative electrode piece includes a three-dimensional skeleton, the three-dimensional skeleton including a first layer skeleton and a second layer skeleton; the first layer skeleton includes one-dimensional conductive fibers; the second layer framework comprises a zero-dimensional material, a one-dimensional material, and a two-dimensional material, the zero-dimensional material being a lithophilic material; The thickness of the three-dimensional skeleton is more than 10 μm and not more than 200 μm, the thickness of the first layer skeleton is more than 0 μm and not more than 10 μm, and the thickness of the second layer skeleton is 10 μm or more and less than 200 μm; The zero-dimensional material is 1% to 30% by mass percentage relative to the mass of the second layer skeleton; the mass ratio of the one-dimensional material to the two-dimensional material is between 1:7 and 20:1; the one-dimensional conductive fiber includes at least one of a multi-walled carbon nanotube and a carbon nanofiber; The zero-dimensional material refers to a particulate material, and the zero-dimensional material includes at least one of a metal material, an oxide, and a nitride. The lithophilic material refers to a material that can interact with lithium ions and induce lithium deposition. The one-dimensional material means a linear material, and the one-dimensional material includes at least one of a multi-walled carbon nanotube and a carbon nanofiber; A secondary battery, wherein the two-dimensional material means a sheet-like material, and the two-dimensional material includes MXene and / or graphene.

2. The negative electrode piece includes a metallic lithium layer, the second layer skeleton is located between the first layer skeleton and the metallic lithium layer; 2. The secondary battery according to claim 1, wherein the metallic lithium layer has a thickness of 1 μm to 100 μm.

3. 3. The secondary battery according to claim 2, wherein the metallic lithium layer has a thickness of 5 μm to 50 μm.

4. (a) the thickness of the three-dimensional skeleton is greater than 30 μm and less than 80 μm, and the thickness of the second layer skeleton is greater than or equal to 30 μm and less than 80 μm; (b) the zero-dimensional material is 1% to 10% by mass; (c) the particle size of the zero-dimensional material is 0.1 μm to 5 μm; (d) the one-dimensional material has a diameter of 1 nm to 2000 nm and an aspect ratio of 0.1 to 20000; The secondary battery according to claim 1 , which satisfies at least one of the following characteristics:

5. (e) the particle size of the zero-dimensional material is 0.1 μm to 1 μm; (f) the one-dimensional material has a diameter of 1 nm to 300 nm and an aspect ratio of 0.67 to 20,000; (g) the one-dimensional material has a diameter of 1 nm to 50 nm and an aspect ratio of 5000 to 20000; The secondary battery according to claim 1 , which satisfies at least one of the following characteristics:

6. (h) the two-dimensional material comprises a titanium element, a carbon element, and a surface group, the surface group comprising at least one of —F, —O, and —OH; (i) When the conductivity of the one-dimensional material is a, a is greater than or equal to 1×10 －６ S / cm, and when the conductivity of the two-dimensional material is b, b satisfies b≧2S / cm, and a and b satisfy b>a; The secondary battery according to claim 1 , which satisfies at least one of the following characteristics:

7. The metal material includes at least one of Ag, Au, Zn, and alloys thereof; The oxide is TiO ２ , SiO ２ , ZnO, SnO ２ , Co ３ O ４ , and Fe ２ O ３ and The nitride is Mo ２ N ３ , and / or Fe ６ N ３ The secondary battery according to claim 1 , comprising:

8. the surface of the zero-dimensional material comprises wettable groups; The wetting groups are -OH, -COOR, -COOH, -NH ２ , and -SO ３ H, 8. The secondary battery according to claim 7, wherein R in the --COOR is selected from the group consisting of a methyl group, an ethyl group, a propyl group, a vinyl group, and an ethynyl group.

9. The secondary battery according to claim 1 , wherein the porosity of the three-dimensional framework satisfies porosity≧80%.

10. 5 mAh / cm ２ 2. The secondary battery according to claim 1, wherein the thickness change rate of the three-dimensional framework is less than 10% when lithium metal is deposited.

11. An electronic device comprising the secondary battery according to any one of claims 1 to 10.

12. A method for manufacturing a secondary battery including a negative electrode piece, comprising: The method for manufacturing the negative electrode piece includes: a. Preparing a solution 2 containing one-dimensional conductive fibers and a solution 1 containing zero-dimensional, one-dimensional, and two-dimensional materials, respectively; b) filtering one of the solution 1 and the solution 2 under suction, and after the suction filtration is completed, adding the other solution and filtering it under suction, and after the suction filtration is completed, drying to obtain a three-dimensional skeleton including a first layer skeleton and a second layer skeleton; c) Composite the three-dimensional framework with lithium metal to obtain lithium metal anode pieces; At least the one-dimensional conductive fiber includes at least one of a multi-walled carbon nanotube and a carbon nanofiber; The zero-dimensional material means a particulate material, and the zero-dimensional material includes at least one of a metal material, an oxide, and a nitride; The one-dimensional material means a linear material, and the one-dimensional material includes at least one of a multi-walled carbon nanotube and a carbon nanofiber; The two-dimensional material refers to a sheet-like material, and the two-dimensional material includes MXene and / or graphene. A method for manufacturing a secondary battery comprising the steps of:

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