Nanocomposite layer, method for forming a nanocomposite layer, and battery

Abstract

A nanocomposite layer includes a nanocarbon tube composite and a lithium salt polymer composite. The nanocarbon tube composite includes surface-modified nanocarbon tubes with positive electric groups and a plurality of nanoparticles with negative electric groups, wherein the plurality of nanoparticles are adsorbed to the surface-modified nanocarbon tubes. The lithium salt polymer composite coats the nanocarbon tube composite and includes a first polymer, a second polymer, and a lithium salt. The nanocomposite layer can improve the lithium ion conductivity of a battery.

Description

Technical Field

[0001] This disclosure relates to a nanocomposite layer, a method for forming the nanocomposite layer, and a battery. Specifically, the nanocomposite layer can be applied to a battery and disposed on the negative electrode of the battery. Background Technology

[0002] Lithium-ion batteries are widely used in electronic devices such as mobile phones and laptops. Currently, lithium-ion batteries are also used in electric vehicles as their power source. A lithium-ion battery typically consists of a positive electrode, a negative electrode, and an electrolyte. The positive electrode undergoes a reduction reaction during discharge, releasing conductive ions (such as Li₂)... + The cathode is reduced to uncharged atoms (such as Li) during discharge. The anode, on the other hand, undergoes an oxidation reaction during discharge and is called the anode.

[0003] However, lithium-ion batteries still face many challenges. For example, uneven lithium-ion deposition after repeated charging and discharging causes dendrite formation on the negative electrode surface. If these dendrites penetrate the electrode separator, they can lead to short circuits, thermal failure, and fires. Therefore, improving energy density and safety is the future direction for lithium-ion battery development. Summary of the Invention

[0004] According to various embodiments of the present invention, a nanocomposite layer is provided. The nanocomposite layer comprises a carbon nanotube composite material and a lithium salt polymer composite. The carbon nanotube composite material includes surface-modified carbon nanotubes with positively charged groups and a plurality of nanoparticles with negatively charged groups, wherein the plurality of nanoparticles are adsorbed onto the surface-modified carbon nanotubes. The lithium salt polymer composite coating is used to coat the carbon nanotube composite material, wherein the lithium salt polymer composite comprises a first polymer, a second polymer, and a lithium salt, wherein the first polymer is a piezoelectric polymer, and the second polymer is a dopant molecule miscible with the first polymer, configured to modify the crystal structure of the first polymer.

[0005] According to certain embodiments of the present invention, the surface of surface-modified carbon nanotubes has amide groups.

[0006] According to certain embodiments of the present invention, the plurality of nanoparticles include silver nanoparticles, gold nanoparticles, aluminum nanoparticles, alumina nanoparticles, or combinations thereof.

[0007] According to certain embodiments of the present invention, the plurality of nanoparticles have an average particle size of about 10 nm to 120 nm.

[0008] According to certain embodiments of the present invention, the first polymer is a piezoelectric polymer comprising polyvinylidene fluoride, polydimethylsiloxane, polyimide, polyvinyl acetate or a combination thereof, and the second polymer is a doped molecule comprising polymethyl methacrylate, polyglutamic acid phenyl ester, 4,4'-oxydiphthalic anhydride or a combination thereof with a ceramic perovskite material.

[0009] According to various embodiments of the present invention, a battery is provided, comprising a negative current collector, a negative electrode located on the negative current collector, a nanocomposite layer located on the negative electrode, a solid electrolyte located on the nanocomposite layer, a positive electrode located on the solid electrolyte, and a positive current collector located on the positive electrode.

[0010] According to certain embodiments of the present invention, the nanocomposite layer has a thickness of about 25 to about 50 micrometers.

[0011] According to various embodiments of the present invention, a negative electrode-free battery is provided, comprising a negative electrode current collector, a nanocomposite layer on the negative electrode current collector, a solid electrolyte on the nanocomposite layer, a positive electrode on the solid electrolyte, and a positive electrode current collector on the positive electrode.

[0012] According to various embodiments of the present invention, a method for forming a nanocomposite layer is provided, comprising mixing a carbon nanotube composite material with an organic solvent, a first polymer, a second polymer, and a lithium salt to form a nanocomposite colloid; and baking the nanocomposite colloid. The carbon nanotube composite material includes surface-modified carbon nanotubes with positively charged groups and a plurality of nanoparticles with negatively charged groups, wherein the plurality of nanoparticles are adsorbed onto the surface-modified carbon nanotubes. The first polymer is a piezoelectric polymer. The second polymer is a dopant molecule miscible with the first polymer, configured to alter the crystal structure of the first polymer.

[0013] According to certain embodiments of the present invention, the method further includes forming the carbon nanotube composite material, including surface treating the carbon nanotubes to form surface-modified carbon nanotubes with positively charged groups; mixing the surface-modified carbon nanotubes with an aqueous solution of nanoparticles to form a mixture; and drying the mixture.

[0014] According to certain embodiments of the present invention, the nanocomposite colloid comprises about 10 wt% to about 20 wt% of a first polymer, about 1.5 wt% to about 3 wt% of a second polymer, and about 5 wt% to about 20 wt% of a lithium salt. Attached Figure Description

[0015] The various aspects of this disclosure will be fully understood from the following detailed description when reading the accompanying drawings. It is worth noting that, according to standard industry practice, the various features are not drawn to scale. In fact, for clarity of discussion, the dimensions of the various features may be arbitrarily increased or decreased.

[0016] Figure 1 A flowchart illustrating a method for forming a nanocomposite layer according to certain embodiments of the present invention.

[0017] Figure 2 A schematic diagram illustrating a carbon nanotube composite material according to certain embodiments of the present invention.

[0018] Figure 3 A schematic diagram illustrating the structure of a nanocomposite layer according to certain embodiments of the present invention.

[0019] Figure 4 A cross-sectional view of a battery according to certain embodiments of the present invention.

[0020] Figure 5 A cross-sectional view of a negative electrode-free half-cell with a nanocomposite layer, illustrated according to an experimental example of the present invention.

[0021] Figure 6 This is a potential-time curve of a negative electrode-free half-cell with a nanocomposite layer according to an experimental example of the present invention.

[0022] Figure 7 This is a potential-time curve of a negative electrode-free half-cell without a nanocomposite layer according to a comparative example of the present invention. Detailed Implementation

[0023] The following describes several embodiments of the present invention with reference to the accompanying drawings. For clarity, many practical details will be described in the following description. However, it should be understood that these practical details are not intended to limit the invention. That is, in some embodiments of the invention, these practical details are not essential. Furthermore, for clarity, the size or thickness of elements may be exaggerated and not drawn to their original dimensions. In addition, for the sake of simplicity, some conventional structures and elements will be shown in the drawings in a simplified schematic manner.

[0024] Spatial relative terms, such as "below," "under," "above," and "above," are used in this document to facilitate the description of the relative relationship between one element or feature and another, as illustrated in the figure. The true meaning of these spatial relative terms includes other orientations. For example, when the figure is rotated 180 degrees vertically, the relationship between one element and another may change from "below" or "under" to "above" or "above." Furthermore, the spatial relative descriptions used in this document should be interpreted in the same way.

[0025] Although the methods disclosed herein are illustrated using a series of operations or steps, the order in which these operations or steps are shown should not be construed as a limitation of the invention. For example, some operations or steps may be performed in a different order and / or simultaneously with other steps. Furthermore, not all illustrated operations, steps, and / or features are required to achieve embodiments of the invention. Additionally, each operation or step described herein may comprise several sub-steps or actions.

[0026] Figure 1 A flowchart illustrating a method for forming a nanocomposite layer according to certain embodiments of the present invention. Figure 1 As shown, method 10 includes operations 12, 14, and 16.

[0027] Please refer to Figure 1 and Figure 2 In operation 12 of method 10, a carbon nanotube composite material 100 is formed. For example... Figure 2 As shown, the carbon nanotube composite material 100 includes surface-modified carbon nanotubes 102 with positively charged groups and multiple nanoparticles 104 with negatively charged groups, and the multiple nanoparticles 104 are adsorbed on the surface-modified carbon nanotubes 102. Specifically, the surface-modified carbon nanotubes 102 and the nanoparticles 104 form covalent bonds.

[0028] In some embodiments, forming the carbon nanotube composite material 100 may include the following operations. First, the carbon nanotubes (not shown) are surface-treated to form surface-modified carbon nanotubes 102. In some embodiments, the surface treatment includes carboxylation, acyl chloride reaction, and amidation reaction of the carbon nanotubes. For example, after carboxylation, the surface of the carbon nanotubes has -COOH groups. Subsequently, after acyl chloride reaction, the -COOH groups are replaced with -COCl groups. Next, after amidation reaction, the -Cl in the -COCl groups on the surface of the carbon nanotubes is replaced with -NH(CH2)2-NH3. + Groups. After multi-layer functionalization, carbon nanotubes can have positively charged groups on their surface. In some embodiments, the surface of the surface-modified carbon nanotubes 102 has amide groups. In some embodiments, the surface-modified carbon nanotubes 102 can be achieved by subjecting carboxylated carbon nanotubes to high temperatures (>350°C). o C) Direct generation using ethylenediamine under high pressure (>6 MPa). In other embodiments, carbon nanotubes are plasma-treated, for example using hydrogen-oxygen plasma, to generate -COOH groups on the surface of the carbon nanotubes, followed by ammonia plasma treatment to generate positively charged NH3 groups.

[0029] In some embodiments, the surface-modified carbon nanotubes 102 comprise multi-walled carbon nanotubes, double-walled carbon nanotubes, single-walled carbon nanotubes, or combinations thereof. In some embodiments, the surface-modified carbon nanotubes 102 have a length of about 5 to 15 micrometers. Carbon nanotubes longer than 15 micrometers are difficult to obtain; while carbon nanotubes shorter than 5 micrometers lose continuity, which is problematic when the resulting nanocomposite layer is subsequently applied to a battery (e.g., ...). Figure 4 The nanocomposite layer 200 shown will lead to an increase in impedance.

[0030] Subsequently, the surface-modified carbon nanotubes 102 and the aqueous solution of nanoparticles 104 can be mixed to form a mixture. In some embodiments, an ultrasonic oscillator can be used to mix the powdered surface-modified carbon nanotubes 102 and the aqueous solution of nanoparticles 104. In some embodiments, the nanoparticles 104 are lithiophilic. In some embodiments, the nanoparticles 104 include silver nanoparticles, gold nanoparticles, aluminum nanoparticles, alumina nanoparticles, or combinations thereof. In some embodiments, the nanoparticles 104 are formed via a hydration method. In some embodiments, the nanoparticles 104 can be formed by reducing metal ions with a reducing agent. For example, the nanoparticles 104 can be... Figure 2 The silver citrate nanoparticles shown have a slightly negatively charged surface (5-15 mV). These nanoparticles are formed by reducing silver ions in an aqueous solution of silver nitrate with sodium citrate, creating bonds that encapsulate silver atoms with citric acid molecules. In other embodiments, sodium borohydride and a mixture of formate and sodium hydroxide can be used instead of sodium citrate as the reducing agent. In some embodiments, multiple nanoparticles 104 have an average particle size of approximately 10 nm to 120 nm. If the particle size of nanoparticles 104 is greater than 120 nm, they tend to aggregate during synthesis and are less likely to form strong adsorption bonds with surface-modified carbon nanotubes 102 to form covalent bonds. When the resulting nanocomposite layer is subsequently applied to a battery, it will affect the stability of the silver particles during charging and discharging. If the particle size of nanoparticles 104 is less than 10 nm, it indicates that silver nitrate has not been completely reduced to silver nanoparticles. In some embodiments, the weight ratio of the surface-modified carbon nanotubes 102 to the aqueous solution of nanoparticles 104 is from 1:10 to about 1:20.

[0031] Next, the above mixture is dried. In some embodiments, the mixture can be dried by baking to form a powder. The powder is then dissolved in an organic solvent and pulverized by an emulsifier to form the carbon nanotube composite material 100. It should be understood that, for ease of understanding, Figure 2The carbon nanotube composite material 100 is illustrated as negatively charged silver citrate nanoparticles 104 adsorbed on the surface of surface-modified carbon nanotubes 102 having positively charged amide groups, but the present invention is not limited thereto.

[0032] Please continue to refer to Figure 1 In step 14 of method 10, the carbon nanotube composite material 100 is mixed with an organic solvent, a first polymer, a second polymer, and a lithium salt to form a nanocomposite colloid. In some embodiments, the carbon nanotube composite material 100 may be mixed uniformly with the organic solvent, the first polymer, and the second polymer before being mixed with the lithium salt. The nanocomposite colloid can be coated onto a suitable substrate (such as the negative electrode of a battery).

[0033] In some embodiments, the organic solvent comprises N-methylpyrrolidone, ethylene carbonate, polycarbonate, dimethyl carbonate, dimethylacetamide, diethyl carbonate, or combinations thereof.

[0034] In some embodiments, the first polymer is a piezoelectric polymer with a high dipole moment and a tendency to form a crystalline structure. In some embodiments, the first polymer is a piezoelectric polymer comprising polyvinylidene fluoride (PVDF), polydimethylsiloxane (PDMS), polyimide (PI), polyvinyl acetate (PVA), or combinations thereof. In some embodiments, the nanocomposite colloid comprises about 10 wt% to about 20 wt% of the first polymer. When the content of the first polymer is too high, the colloidal rheological properties of the nanocomposite colloid become excessively high, affecting the film-forming properties of the subsequently formed nanocomposite layer.

[0035] In some embodiments, the second polymer is a dopant molecule that increases the mechanical strength of the first polymer, changes its viscosity, or increases its piezoelectric properties, and is miscible with the first polymer. The crystal structure of the first polymer can be altered by controlling the doping amount and morphology of the second polymer. In some embodiments, the second polymer is a dopant molecule comprising poly(methyl methacrylate) (PMMA), poly(γ-benzyl-L-glutamate), 4,4'-oxydiphthalic anhydride, or a combination of the above polymers and ceramic perovskite materials. In some embodiments, the nanocomposite colloid contains about 1.5 wt% to about 3 wt% of the second polymer. When the content of the second polymer is too high, the dipole-dipole interaction between the second polymer and the first polymer is greater, resulting in excessively low rheological properties of the nanocomposite colloid. This makes the nanocomposite colloid difficult to coat, and the resulting coating becomes brittle and loses its protective function due to excessive stress.

[0036] The first and second polymers can improve the surface coating of carbon nanotubes, thereby reducing agglomeration. Furthermore, the first and second polymers can adjust the viscosity of the nanocomposite colloid. Specifically, when the surface-modified carbon nanotubes 102 and nanoparticles 104 form covalent bonds, the overall structure remains electrically neutral, losing the electrically bilayer dispersion characteristics inherent in the positively charged surface-modified carbon nanotubes 102. Therefore, the quality of polymer coating affects the overall dispersion characteristics of the nanocomposite colloid. Poor dispersion results in too low a viscosity, causing the formed nanocomposite layer to lose its protective properties. Conversely, excessively high viscosity makes the nanocomposite colloid difficult to coat. Therefore, the coating characteristics of the polymer on the carbon nanotube composite material 100 and the viscosity of the nanocomposite colloid have a significant impact on the application of the nanocomposite layer.

[0037] In some embodiments, the lithium salt comprises lithium bis(fluorosulfonyl)imide, lithium bis(oxalato)borate, lithium tetrafluoroborate, lithium difluorooxalato)borate, lithium bis(fluorosulfonyl)imide, lithium difluorophosphate, lithium tetrafluorooxalatophosphate, or combinations thereof. In some embodiments, the nanocomposite colloid comprises about 5 wt% to about 20 wt% of the lithium salt. The lithium salt can increase the lithium-ion conductivity of the nanocomposite colloid to assist lithium-ion conduction and facilitate its intermetallic reaction with adjacent metal nanoparticles to achieve dynamic equilibrium.

[0038] Please refer to Figure 1 In step 16 of method 10, the nanocomposite colloid is baked. In some embodiments, after the nanocomposite colloid is coated onto the substrate, it is baked at 120-150°C. o Baking the nanocomposite colloid at C causes the organic solvent to dry and form Figure 3 The nanocomposite layer 200 is shown. In some embodiments, the nanocomposite layer 200 can be used in a battery. For example, the nanocomposite layer 200 can be formed on the negative electrode of the battery, as will be discussed later. Figure 4 Detailed explanation follows.

[0039] Figure 3 A schematic diagram illustrating the structure of a nanocomposite layer 200 according to certain embodiments of the present invention. Figure 3 As shown, the nanocomposite layer 200 includes a carbon nanotube composite material 100 and a lithium salt polymer composite 110.

[0040] The carbon nanotube composite material 100 includes surface-modified carbon nanotubes 102 with positively charged groups and multiple nanoparticles 104 with negatively charged groups, wherein the multiple nanoparticles 104 are adsorbed on the surface-modified carbon nanotubes 102. The carbon nanotube composite material 100 can be any carbon nanotube composite material 100 as described above, and will not be repeated here.

[0041] A lithium salt polymeric complex 110 coats a carbon nanotube composite material 100. In some embodiments, the lithium salt polymeric complex 110 comprises a first polymer, a second polymer, and a lithium salt. Specifically, the first polymer and the second polymer described above can form a complex with the lithium salt. Examples of the first polymer, the second polymer, and the lithium salt can be any of the examples described above, and will not be repeated here.

[0042] Another aspect of the present invention is a battery. Figure 4 A cross-sectional view of a battery 1000 illustrated according to certain embodiments of the present invention. Figure 4 As shown, battery 1000 includes a negative current collector 310, a negative electrode 300, a nanocomposite layer 200, a solid electrolyte 400, a positive electrode 500, and a positive current collector 510. In some embodiments, battery 1000 can be a lithium-ion battery. For example, battery 1000 can be a lithium cobalt (LCO) battery, a lithium nickel cobalt manganese (NCM) battery, a lithium iron phosphate (LFP) battery, a lithium cobalt binary battery, a ternary battery, or the like.

[0043] In some embodiments, the negative current collector 310 can be any suitable material, such as copper foil. The negative electrode 300 is disposed on the negative current collector 310. In some embodiments, the negative electrode 300 comprises any suitable material, such as lithium metal, graphite, or silicon carbide. In some embodiments, the negative electrode 300 may be omitted.

[0044] A nanocomposite layer 200 is disposed between the negative electrode 300 and the solid electrolyte 400. The nanocomposite layer 200 can be formed by drying the aforementioned nanocomposite colloid. The nanocomposite layer 200 comprises a carbon nanotube composite material 100 and a lithium salt polymer composite 110. The nanocomposite layer 200 can be any nanocomposite layer 200 as described above. In some embodiments, the battery is a negative electrode-less battery, in which case the nanocomposite layer 200 is disposed on the negative electrode current collector 310.

[0045] The carbon nanotube composite material 100 includes surface-modified carbon nanotubes 102 with positively charged groups and multiple nanoparticles 104 with negatively charged groups, wherein the multiple nanoparticles 104 are adsorbed onto the surface-modified carbon nanotubes 102, such as... Figure 2 As shown, the covalent bonds formed between the surface-modified carbon nanotubes 102 and the nanoparticles 104 result in a very strong attraction between them. When lithium ions are inserted and extracted during the charging and discharging process of the battery 1000, the metal nanoparticles 104 undergo volume changes due to the formation of an intermetallic compound by intermingling with the lithium ions. At this time, the interaction force between the surface-modified carbon nanotubes 102 and the metal nanoparticles 104 can stabilize the metal nanoparticles 104 (e.g., ...). Figure 2 The silver nanoparticles shown reduce the agglomeration of silver nanoparticles into ineffective particles due to desorption from the surface-modified carbon nanotubes 102. Furthermore, the surface-modified carbon nanotubes 102 can also increase the conductivity of the nanocomposite layer 200. The carbon nanotube composite material 100 can be used to homogenize the rate and concentration of lithium ions migrating between the positive electrode 500 and the negative electrode 300.

[0046] The lithium salt polymer complex 110 comprises the first polymer, the second polymer, and the lithium salt as described above. By mixing lithium ions from the lithium salt with the metal nanoparticles 104, it is possible to promote the formation of an intermetallic compound with the metal nanoparticles 104 during the migration of lithium ions at the interface of the negative electrode 300, thereby achieving a dynamic equilibrium of lithium ions.

[0047] The nanocomposite layer 200 formed on the negative electrode 300 of the battery 1000 can effectively improve lithium-ion conductivity, enhance the battery's cycle performance under high-rate discharge, and reduce lithium dendrite formation. In some embodiments, the nanocomposite layer 200 has a thickness of about 25 to about 50 micrometers. If the thickness of the nanocomposite layer 200 is greater than 50 micrometers, it will increase the device impedance. If the thickness is less than 25 micrometers, it is easy to lose its protective effect on the negative electrode due to uneven coating.

[0048] Please continue to refer to this. Figure 4A solid electrolyte 400 is disposed on the nanocomposite layer 200. In some embodiments, the solid electrolyte 400 comprises any suitable solid electrolyte material. A positive electrode 500 is disposed on the solid electrolyte 400. In some embodiments, the positive electrode 500 comprises any suitable positive electrode material. A positive current collector 510 is disposed on the positive electrode 500. In some embodiments, the positive current collector 510 comprises any suitable material, such as aluminum foil.

[0049] The following embodiments are provided to illustrate specific aspects of the present invention and to enable those skilled in the art to practice the invention. However, the following embodiments should not be construed as limiting the invention.

[0050] Experimental Example 1: A half-cell without a negative electrode and having a nanocomposite layer

[0051] Figure 5 This is a cross-sectional view of a 2000 half-cell without a negative electrode and featuring a nanocomposite layer. Figure 5 As shown, the half-cell 2000 includes a negative current collector 310, a nanocomposite layer 200, a separator 400', and a positive electrode 500.

[0052] The negative current collector 310 is a copper foil with a thickness of approximately 8 micrometers. The nanocomposite layer 200 is manufactured by the above method and has a thickness of approximately 15 micrometers. The nanocomposite layer 200 is composed of 0.2 wt% of... Figure 2 The carbon nanotube composite material shown is composed of a lithium salt polymer complex containing 11.5 wt% polyvinylidene fluoride, 1.6 wt% polymethyl methacrylate, and 8.2 wt% lithium bis(trifluoromethanesulfonyl)imide. The separator 400' is manufactured by W-scope and has a thickness of approximately 20 micrometers. The positive electrode 500 is lithium metal and has a thickness of approximately 200 micrometers. This electrodeless half-cell demonstrates the use of a liquid electrolyte (not shown in the figure).

[0053] Comparative Example 1: Half-cell without a negative electrode and without a nanocomposite layer

[0054] The half-cell structure of Comparative Example 1 is similar to that of the half-cell 2000 of Example 1, except that the half-cell of Comparative Example 1 does not have a nanocomposite layer 200.

[0055] The above experimental example 1 and comparative example 1 were subjected to an A / cm test at 0.5 mA / cm. 2 Electroplating tests were conducted at current density to evaluate the battery characteristics when the nanocomposite layer is used in a battery. The results are as follows: Figure 6 and Figure 7 As shown. During the electroplating process, lithium ions move from the lithium metal positive electrode 500 to the copper negative electrode current collector 310 and deposit on the surface of the copper negative electrode current collector 310. At this time, a significant decrease in potential can be observed. Figure 6As shown, silver ions in the nanocomposite layer 200 of Experimental Example 1 can react with lithium ions at the interface of the negative electrode current collector 310 to produce a mesometallic compound. Figure 7 Comparative Example 1 shown does not have a nanocomposite layer 200, so no intermetallic reaction occurs at the interface.

[0056] The electroplating process can include ion passage, electrolyte diffusion, charge transfer, atomic surface adsorption, surface diffusion, grain nucleation, and grain growth. Grain nucleation and grain growth have clearly quantifiable activation energies (voltages below 0 volts), denoted as overpotentials. The smaller the overpotential, the more uniform the electroplated film, and the closer it is to two-dimensional growth (i.e., a thin film); while the larger the overpotential, the closer it is to one-dimensional growth, and the easier it is to form lithium dendrites. Please refer to [reference needed]. Figure 6 and Figure 7 The overpotential of Experimental Example 1 was about 50 mV, and the overpotential of Comparative Example 1 was about 95 mV. Therefore, Experimental Example 1 with the nanocomposite layer 200 can form a thin film with a more uniform thickness, rather than lithium dendrites.

[0057] As described above, according to embodiments of the present invention, a nanocomposite layer, a method for forming the same, and a battery comprising the aforementioned nanocomposite layer are provided. The nanocomposite layer is disposed between the negative electrode and the solid electrolyte of the battery. The nanocomposite layer of the present invention is formed by drying a nanocomposite colloid comprising a carbon nanotube composite material, an organic solvent, a first polymer, a second polymer, and a lithium salt. The carbon nanotube composite material comprises surface-modified carbon nanotubes with positively charged groups and a plurality of nanoparticles with negatively charged groups. The nanoparticles and the surface-modified carbon nanotubes are covalently bonded and have a very strong attraction to each other. Therefore, under high-rate discharge of the battery, the nanoparticles have good stability and can prevent them from desorbing from the surface-modified carbon nanotubes. In addition, the nanocomposite layer can effectively improve lithium-ion conductivity, improve the cycle performance of the battery under high-rate discharge, and reduce the formation of lithium dendrites.

[0058] Although the present invention has been disclosed above by way of embodiments, it is not intended to limit the present invention. Those skilled in the art can make various modifications and refinements without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention shall be determined by the appended claims.

[0059] [Symbol Explanation]

[0060] 10: Method

[0061] 12, 14, 16: Operations

[0062] 100: Carbon nanotube composite materials

[0063] 102: Surface-modified carbon nanotubes

[0064] 104: Nanoparticles

[0065] 110: Lithium salt polymer complex

[0066] 200: Nanocomposite layer

[0067] 300: Negative electrode

[0068] 310: Negative current collector

[0069] 400: Solid electrolyte

[0070] 400': Diaphragm

[0071] 500: Positive electrode

[0072] 510: Positive current collector

[0073] 1000: Battery.

Claims

1. A nanocomposite layer for a battery, characterized by, Comprising: A nanocarbon tube composite material includes surface-modified nanocarbon tubes with positive electric groups and a plurality of nanoparticles with negative electric groups, wherein the plurality of nanoparticles are adsorbed to the surface-modified nanocarbon tubes, and the surface of the surface-modified nanocarbon tubes has NH(CH2)2-NH3 + groups, the plurality of nanoparticles include silver nanoparticles, gold nanoparticles, aluminum nanoparticles, aluminum oxide nanoparticles, or a combination thereof; and a lithium salt polymer complex coated on the nanocarbon tube composite, wherein the lithium salt polymer complex comprises a first polymer, a second polymer, and a lithium salt, wherein the first polymer is a piezoelectric polymer, and the second polymer is a dopant molecule that is miscible with the first polymer, configured to change a crystal structure of the first polymer.

2. The nanocomposite layer of claim 1, wherein The plurality of nanoparticles has an average particle size of 10 nm to 120 nm.

3. The nanocomposite layer of claim 1, wherein, The piezoelectric polymer comprises polyvinylidene fluoride, polydimethylsiloxane, polyimide, polyvinyl acetate, or a combination thereof, and the dopant molecule comprises polymethyl methacrylate, polyphenyl glutamate, 4,4'-oxybisphthalic anhydride, or a combination thereof with a ceramic perovskite material.

4. A battery, characterized by Comprising: a negative current collector; a negative electrode on the negative current collector; the nanocomposite layer according to any one of claims 1 to 3 on the negative electrode; a solid-state electrolyte on the nanocomposite layer; a positive electrode on the solid-state electrolyte; and a positive current collector on the positive electrode.

5. The battery of claim 4, wherein, The nanocomposite layer has a thickness of 25 to 50 micrometers.

6. A non-aqueous electrolyte secondary battery characterized by comprising: Comprising: a negative current collector; the nanocomposite layer according to any one of claims 1 to 3 on the negative current collector; a solid-state electrolyte on the nanocomposite layer; a positive electrode on the solid-state electrolyte; and a positive current collector on the positive electrode.

7. A method of forming a nanocomposite layer, characterized by, Comprising: A nanocomposite gel is formed by mixing a nanotube composite material, an organic solvent, a first polymer, a second polymer, and a lithium salt, wherein the nanotube composite material includes surface-modified nanotubes with positive groups and a plurality of nanoparticles with negative groups, the plurality of nanoparticles are adsorbed on the surface-modified nanotubes, and the surface of the surface-modified nanotubes has NH(CH2)2-NH3 groups + The first polymer is a piezoelectric polymer, the second polymer is a doping molecule that is miscible with the first polymer and is configured to change the crystal structure of the first polymer, and the plurality of nanoparticles include silver nanoparticles, gold nanoparticles, aluminum nanoparticles, aluminum oxide nanoparticles, or a combination thereof. baking the nanocomposite colloid.

8. The method of claim 7, wherein, Also comprising forming the nanocarbon tube composite, comprising: surface-treating nanocarbon tubes to form the surface-modified nanocarbon tubes with positively charged groups; mixing the surface-modified nanocarbon tubes with an aqueous solution of nanoparticles to form a mixture; and drying the mixture.

9. The method according to claim 7 or 8, characterized in that, The nanocomposite colloid comprises 10 wt% to 20 wt% of the first polymer, 1.5 wt% to 3 wt% of the second polymer, and 5 wt% to 20 wt% of the lithium salt.

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