Functional current collector with improved thermal stability and preparation method thereof, pole piece and battery

Abstract

The application discloses a functional current collector with improved thermal stability, a preparation method thereof, a pole piece and a battery. The structural composition of the functional current collector comprises a polymer base layer, wherein the polymer base layer contains a negative thermal expansion material; an aluminum oxide primer layer is arranged on both sides of the polymer base layer; and an aluminum metal plating layer is arranged on both sides of the aluminum oxide primer layer. The negative thermal expansion material is an X-MOF / rGO composite material, wherein X is selected from any one of Cu, Fe, Ni and Co; and the ligand of the MOF is aspartic acid. The X-MOF / rGO introduced in the polymer base layer realizes the synergistic improvement of the thermal stability, interface durability and conductivity.

Description

Technical Field

[0001] This invention relates to the field of battery technology, specifically to a functional current collector for improving thermal stability, its preparation method, an electrode, and a battery. Background Technology

[0002] The functional current collector exhibits significant advantages in battery safety and energy density through an innovative sandwich structure design of a metal conductive layer-polymer substrate-metal conductive layer. The middle layer uses polymer materials such as PET or PP, whose insulating and flame-retardant properties can quickly form a melt-break isolation when the battery suffers mechanical damage, effectively blocking the thermal runaway chain reaction. This structural design not only solves the short-circuit risk caused by burrs in traditional metal current collectors, but also significantly reduces the overall weight through lightweight material replacement. At the same time, the thinner structure provides more space for active materials, significantly improving the battery's energy density.

[0003] However, this technology faces challenges in thermal stability, primarily due to the significant differences in the coefficients of thermal expansion of the various layers. The difference in expansion stress between the polymer substrate and the metal layer during temperature changes can easily lead to interfacial delamination and coating peeling, affecting battery cycle life and high-rate performance. This thermomechanical mismatch is particularly pronounced under high-temperature conditions or during rapid charge and discharge processes, becoming a key bottleneck restricting the reliability of functional current collectors. Summary of the Invention The purpose of this invention is to provide a functional current collector with improved thermal stability, its preparation method, electrode, and battery. By optimizing the polymer substrate in the sandwich structure, the thermal stability of the functional current collector is improved, thereby increasing the product yield.

[0004] This invention is achieved through the following technical solution: The first aspect of this application provides a functional current collector that improves thermal stability, comprising: A polymer substrate layer, wherein the polymer substrate layer contains a negative thermal expansion material; An alumina underlayer is disposed on both sides of a polymer substrate layer; An aluminum metal coating, wherein the aluminum metal coating is disposed on both sides of an aluminum oxide underlayer; The negative thermal expansion material is an X-MOF / rGO composite material, wherein X is selected from any one of Cu, Fe, Ni, and Co; and the ligand of MOF is aspartic acid.

[0005] The thickness of the polymer substrate is 4~10μm.

[0006] To optimize the above technical solution, the specific measures also include: The second aspect of this application provides a method for preparing a functional current collector with improved thermal stability, comprising the following steps: S1: Prepare a polymeric substrate layer containing a negative thermal expansion material; S2: Prepare an alumina underlayer on both sides of the polymer substrate layer; S3: Prepare aluminum metal coatings on both sides of the aluminum oxide underlayer; The method for preparing the polymer substrate layer containing negative thermal expansion material in step S1 is as follows: S1.1: Mix a compound containing Cu, Fe, Ni or Co with aspartic acid and a base; S1.2: The mixture from step S1.1 is mixed with an excess of rGO suspension to obtain an X-MOF / rGO composite material, where X is selected from Cu, Fe, Ni, and Co. S1.3: Mix the X-MOF / rGO composite material with a polymer material, and then stretch, shape and cut it to obtain a polymer base layer containing a negative thermal expansion material.

[0007] The compound containing Cu, Fe, Ni or Co mentioned in step S1.1 is a nitrate.

[0008] Furthermore, in step S1.1, the mass ratio of the compound containing Cu, Fe, Ni, or Co to aspartic acid and the base is 5~7:2:0.5~1.5.

[0009] Further, in step S1.1, the compound containing Cu, Fe, Ni or Co is mixed with aspartic acid and a base, and then water is added to make the solid-liquid ratio 2.5~3.5:1. The mixture is stirred and filtered to obtain a mixed product.

[0010] Furthermore, in step S1.3, the mixing mass ratio of the X-MOF / rGO composite material to the polymer material is 1.2~1.4:1.

[0011] Furthermore, in step S1.3, the heating temperature used for shaping is 190~210℃, the time is 3~6 seconds, and after shaping, it is air-cooled to 45~55℃.

[0012] A third aspect of this application provides an electrode comprising a functional current collector with improved thermal stability prepared by the above method.

[0013] A fourth aspect of this application provides a battery comprising the aforementioned electrode.

[0014] Compared with the prior art, the beneficial effects of the present invention are: This invention achieves a synergistic improvement in thermal stability, interfacial durability, and electrical conductivity by introducing X-MOF / rGO into the polymer substrate layer: Introducing X-MOF / rGO composite material (X=Cu / Fe / Ni / Co) into the polymer substrate layer effectively counteracts the thermal expansion of the substrate by utilizing its negative thermal expansion characteristics. This characteristic significantly reduces the coating peeling problem caused by the difference in thermal expansion coefficients during thermal cycling, thereby improving the adhesion between the coating and the substrate. Furthermore, the X-MOF / rGO composite material itself is conductive, which makes the base film conductive, thereby improving the conductivity of the composite aluminum foil and enhancing its rate performance.

[0015] The synergistic effect of the three-dimensional conductive network formed by rGO in the composite material and the metal nodes enables the base film itself to have conductive function, allowing for the use of thinner metal coatings and increasing the loading of active materials; the combination of nitrate and aspartic acid ligands ensures uniform dispersion of metal ions, stable MOF crystal growth quality, high yield, and reduced overall production cost. Detailed Implementation The present invention will be further described in detail below through specific embodiments, but it should not be construed as limiting the scope of the subject matter of the present invention to the following embodiments. All technologies implemented based on the above content of the present invention fall within the scope of the present invention.

[0016] Unless otherwise specified, the experimental methods used in the following examples are conventional methods, and the reagents, methods and equipment used are conventional reagents, methods and equipment in this technical field.

[0017] This invention provides a functional current collector that improves thermal stability, comprising: The polymer base layer contains a negative thermal expansion material; Alumina is used as the underlayer, and the alumina underlayer is set on both sides of the polymer substrate layer; Aluminum metal coating, which is applied to both sides of the aluminum oxide underlayer; The negative thermal expansion material is an X-MOF / rGO composite material, where X is selected from any one of Cu, Fe, Ni, and Co; and the ligand of MOF is aspartic acid.

[0018] In some embodiments, the thickness of the polymer substrate layer is 4~10 μm.

[0019] This invention also provides a method for preparing a functional current collector with improved thermal stability, comprising the following steps: S1: Prepare a polymeric substrate layer containing a negative thermal expansion material; S2: Prepare an alumina underlayer on both sides of the polymer substrate layer; S3: Prepare aluminum metal coatings on both sides of the aluminum oxide underlayer; The method for preparing the polymer substrate layer containing negative thermal expansion material in step S1 is as follows: S1.1: Mix a compound containing Cu, Fe, Ni or Co with aspartic acid and a base; S1.2: The mixture from step S1.1 is mixed with an excess of rGO suspension to obtain an X-MOF / rGO composite material, where X is selected from Cu, Fe, Ni, and Co. S1.3: Mix the X-MOF / rGO composite material with a polymer material, and then stretch, shape and cut it to obtain a polymer base layer containing a negative thermal expansion material.

[0020] In some embodiments, the compound containing Cu, Fe, Ni or Co in step S1.1 is a nitrate; the alkali is selected from sodium hydroxide or other similar alkaline substances.

[0021] In some embodiments, the mass ratio of the compound containing Cu, Fe, Ni or Co in step S1.1 to aspartic acid and the base is 5~7:2:0.5~1.5.

[0022] In some embodiments, in step S1.1, the compound containing Cu, Fe, Ni or Co is mixed with aspartic acid and a base, and then water is added to make the solid-liquid ratio 2.5~3.5:1. The mixture is stirred and filtered to obtain a mixed product.

[0023] In some embodiments, in step S1.3, the mixing mass ratio of the X-MOF / rGO composite material to the polymer material is 1.2~1.4:1.

[0024] In some embodiments, step S1.3, stretching includes longitudinal stretching and transverse stretching. The longitudinal stretching preheating roller is set to a temperature of 60-80°C, the slow stretching roller to 80-85°C, the fast stretching roller to 30°C, and the cooling rollers to 30°C and 50°C. The longitudinal stretching ratio is set to 3-3.5 times. The transverse stretching preheating roller is set to a temperature of 80-100°C, the slow stretching roller to 100-105°C, and the longitudinal stretching ratio is set to 3-3.5 times.

[0025] In some embodiments, in step S1.3, the heating temperature used for shaping is 190~210℃, the time is 3~6 seconds, and after shaping, it is air-cooled to 45~55℃.

[0026] The main material of the polymer substrate layer of the present invention can be selected from polyethylene terephthalate (PET), polypropylene (PP), polybutylene terephthalate (PBT), polyethylene naphthalate (PEN), polyethylene (PE), polypropylene, polyvinyl chloride (PVC), polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), polyphenylene sulfide (PPS), polyphenylene ether (PPO), polystyrene (PS), polyimide (PI), etc.

[0027] This invention introduces the negative thermal expansion material X-MOF / rGO composite material into the polymer substrate layer, reducing the thermal expansion coefficient of the polymer substrate layer, thereby reducing the generation of thermal stress and the coating delamination caused by the difference in expansion coefficients during high-temperature cycling; and the X-MOF / rGO composite material itself is conductive, thereby making the base film conductive, thereby improving the conductivity of the composite aluminum foil and improving the rate performance.

[0028] In X-MOF / rGO composite materials, X is selected from Cu, Fe, Ni, and Co. These metal MOF materials (such as Cu-MOF, Fe-MOF, etc.) can form composite materials with negative thermal expansion characteristics through the combination of ligand aspartic acid and rGO, effectively offsetting the expansion stress of the polymer substrate at high temperature. The d electron orbital characteristics of transition metals (Cu / Fe / Ni / Co) enable their MOF structures to have tunable thermal expansion coefficients.

[0029] In steps S2 and S3 of this invention, the alumina underlayer and the aluminum metal coating are prepared by vapor deposition. When preparing the alumina underlayer, at high temperature, some Al atoms in the aluminum vapor will replace the X atoms in the X-MOF / rGO composite material before being oxidized, thereby forming the Al-MOF / rGO composite material and forming chemical bonds, which further enhances the bonding force between the underlayer and the base film.

[0030] The synergistic effect of the three-dimensional conductive network formed by rGO in the composite material and the metal nodes endows the base film with conductive properties. This allows for the use of thinner metal coatings, which can be reduced to 1~2μm (compared to the traditional 3~6μm), and also increases the loading of active materials.

[0031] This invention employs aspartic acid ligands. The interaction between the carboxyl group in aspartic acid and rGO can enhance interfacial bonding, while the coordination ability of transition metals, such as Cu... 2+ The strong binding with carboxyl groups can improve the structural stability of composite materials; Compared to other ligands, such as terephthalic acid ligands, which are prone to carbonization at high temperatures, aspartic acid ligands have better thermal stability; and imidazole ligands, which have weak interfacial binding with rGO, aspartic acid ligands enhance complexation through multiple interactions.

[0032] Preferably, the compound containing Cu, Fe, Ni or Co in this invention is a nitrate. Nitrates have high solubility in aqueous solution, which can ensure that the metal ions and aspartic acid ligands are in full contact, promoting the uniform nucleation and growth of MOF crystals. The weak coordination of nitrate ions can reduce the interference with the coordination environment of the metal center, which is beneficial to the directional binding of aspartic acid carboxyl groups to metal ions.

[0033] The present invention also provides an electrode comprising a functional current collector with improved thermal stability prepared by the above method.

[0034] The present invention also provides a battery comprising the above-described electrode.

[0035] The technical solution of the present invention will be further described in detail below with reference to specific embodiments: Example 1 In this embodiment, Cu-MOF / rGO composite material and PET are combined in a 1:1 mass ratio, with a total base film thickness of 6 μm. The film is then deposited by vapor deposition. The specific steps are as follows: First, copper nitrate, aspartic acid, and sodium hydroxide were mixed in a mass ratio of 6:2:1, and water (equivalent to 1 / 3 of the solid mass) was added (solid-liquid ratio 3:1). The mixture was stirred at 50°C for 30 minutes and then filtered. The solid particles were then mixed with the rGO suspension (solid ratio 5:1), ultrasonically dispersed for 15 minutes, and filtered again. The composite material was washed with ethanol and vacuum dried at 80°C for 6 hours, and finally ground into a fine powder. Next, all the raw materials for the PET film were dried, and then the Cu-MOF / rGO composite material was added. The mass ratio of Cu-MOF / rGO composite material to PET was 1:1, and the mixture was stirred for 1 hour.

[0036] The film is initially formed by extrusion through a die, and then subjected to longitudinal and transverse stretching: the longitudinal stretching preheating roller is set to a temperature of 70°C, the slow stretching roller to a temperature of 85°C, the fast stretching roller to a temperature of 30°C, and the cooling rollers to temperatures of 30°C and 50°C, with a longitudinal stretching ratio of 3.2; the transverse stretching preheating roller is set to a temperature of 90°C, the slow stretching roller to a temperature of 105°C, with a longitudinal stretching ratio of 3.2, a heat setting temperature of 200°C, a time of 4 seconds, and then air-cooled to 50°C after setting.

[0037] After the formed film is slit, measured, and corona treated, it is then magnetron sputtering / evaporation deposited onto the film. The unwinding end is at 120N and the winding end at 100N. After the winding carriage enters the evaporation chamber, a vacuum of 5*10 is applied. -3 At Pa, the winding carriage is started, with the speed controlled at 290 m / min. Simultaneously, the evaporation boat is heated and aluminum wire is fed at a speed of 330 mm / min. Oxygen is then introduced to deposit aluminum oxide on the base film surface, with a thickness of 50 nm. The vacuum level is controlled at 5*10. -2 Pa; then, after breaking the vacuum, an aluminum layer with a thickness of 1 μm was deposited in the same manner.

[0038] Example 2 The scheme in this embodiment is basically the same as that in embodiment 1, except that the mass ratio of Cu-MOF / rGO composite material to PET is 1.2:1.

[0039] Example 3 The scheme in this embodiment is basically the same as that in embodiment 1, except that the mass ratio of Cu-MOF / rGO composite material to PET is 1.4:1.

[0040] Example 4 The scheme in this embodiment is basically the same as that in Embodiment 1, except that the mass ratio of Cu-MOF / rGO composite material to PET is 1.6:1.

[0041] Example 5 The scheme in this embodiment is basically the same as that in embodiment 1, except that the mass ratio of Cu-MOF / rGO composite material to PET is 1.8:1.

[0042] Example 6 The scheme of this embodiment is basically the same as that of embodiment 1, except that: in this embodiment, Fe-MOF / rGO composite material and PET are combined, the mass ratio of Fe-MOF / rGO composite material and PET is 1.2:1, the total thickness of the base film is 6μm, and then the film is deposited by vapor deposition; that is, the raw material copper nitrate in embodiment 1 is replaced with iron nitrate, and everything else is the same as in embodiment 1.

[0043] Example 7 The scheme of this embodiment is basically the same as that of embodiment 1, except that: in this embodiment, Ni-MOF / rGO composite material and PET are combined, the mass ratio of Ni-MOF / rGO composite material and PET is 1.2:1, the total thickness of the base film is 6μm, and then the film is deposited by vapor deposition; that is, the raw material copper nitrate in embodiment 1 is replaced with nickel nitrate, and everything else is the same as in embodiment 1.

[0044] Example 8 The scheme of this embodiment is basically the same as that of embodiment 1, except that: in this embodiment, the Co-MOF / rGO composite material and PET are combined, the mass ratio of Co-MOF / rGO composite material and PET is 1.2:1, the total thickness of the base film is 6μm, and then the film is deposited by vapor deposition; that is, the raw material copper nitrate in embodiment 1 is replaced with cobalt nitrate, and everything else is the same as in embodiment 1.

[0045] Comparative Example 1 The scheme of this comparative example is basically the same as that of Example 1, except that aspartic acid is not used as the ligand, but 2-methylimidazole is used instead; that is, aspartic acid in Example 1 is replaced with 2-methylimidazole, and everything else is the same as that of Example 1.

[0046] Comparative Example 2 The scheme of this comparative example is basically the same as that of Example 1, except that: aspartic acid is not used as the ligand, but terephthalic acid is used instead; that is, the aspartic acid in Example 1 is replaced with terephthalic acid, and everything else is the same as that of Example 1.

[0047] Comparative Example 3 This comparative example does not use a combination of the composite and PET; instead, PET is used directly as the base film with a thickness of 6 μm. The film is then deposited via vapor deposition, and the specific steps are as follows: First, all raw materials are dried to remove moisture. Then, the PET film raw material is hot-melted at 270±5℃. Next, the molten shape memory polymer is added into the mold and extruded through the mold to form the initial shape of the film. Then, longitudinal and transverse stretching are performed: the temperature of the preheating roller for longitudinal stretching is set at 70℃, the temperature of the slow stretching roller is 85℃, the temperature of the fast stretching roller is 30℃, and the temperature of the cooling rollers is 30℃ and 50℃, with a longitudinal stretching ratio of 3.2. The temperature of the preheating roller for transverse stretching is set at 90℃, the temperature of the slow stretching roller is 105℃, the longitudinal stretching ratio is set at 3.2, the heat setting temperature is 200℃, the time is 4 seconds, and after setting, it is air-cooled to 50℃.

[0048] After the formed film is slit, measured, and corona treated, it is then magnetron sputtering / evaporation deposited onto the film. The unwinding end is at 120N and the winding end at 100N. After the winding carriage enters the evaporation chamber, a vacuum of 5*10 is applied. -3 At Pa, the winding carriage is started, with the speed controlled at 290 m / min. Simultaneously, the evaporation boat is heated and aluminum wire is fed at a speed of 330 mm / min. Oxygen is then introduced to deposit aluminum oxide on the base film surface, with a thickness of 50 nm. The vacuum level is controlled at 5*10. -2 Pa; then, after breaking the vacuum, an aluminum layer with a thickness of 1 μm was deposited in the same manner.

[0049] Conductivity test: Using the Probe Technology RTS-7 four-probe tester, cut the sample into 10*10cm pieces and place them under the probes. Test each sample three times and take the average value. According to the formula, resistivity ρ=V / I*2πS, conductivity σ=1 / ρ. Residual stress testing: The residual stress of the functional current collector was measured using a μ-360s X-ray residual stress analyzer from QUANTUM Quantum Scientific Instruments Trading (Beijing) Co., Ltd. The specific procedure was as follows: the functional current collector was placed in an oven and heated at 80°C for 1 hour; then, the sample was cut and placed in the test chamber, and X-rays were applied to the sample. After a single-angle incident radiation, a complete Debye ring was obtained using a two-dimensional detector; the change in interplanar spacing under stress and the corresponding stress were calculated by comparing the difference between the Debye ring without stress and the deformed Debye ring under stress.

[0050] The above-mentioned functional current collectors were immersed in electrolyte and their peel strength was tested. Electrolyte soaking: Cut the functional current collector into 6*8cm pieces and seal them with aluminum-plastic film, with 2 composite films per bag; then inject 10ml of ternary electrolyte into each bag of samples in a glove box and seal them. After different number of days (1 / 3 / 7 / 15 / 30), take out the samples and soak them in ethanol in a fume hood to clean the surface electrolyte.

[0051] Peel strength test: Take a test sample with a size of 15*100mm, attach 3M-9080A-15mm tape to a stainless steel plate, then evenly attach the test sample to the double-sided tape, and use a 2kg standard small pressure roller to press back and forth twice. Then attach 3M-9080A-14mm tape to the sample surface, and use a 2kg standard small pressure roller to press back and forth twice. After that, take the pressed sample to a tensile testing machine and stretch it 180° at a speed of 100mm / min and a width of 15mm. The result is taken as the maximum value.

[0052] Table 1 Physical data of composite membranes in various cases

[0053] Table 2 shows the peel force data of the composite film in the examples.

[0054] As can be seen from Examples 1 to 5, when the X-MOF / rGO content ratio is between 1:1 and 1.8:1, the conductivity-thermal stability balance test data shows that Example 1 has the lowest sheet resistance, but the stress increase is significant after heating; Example 5 has an increased sheet resistance, but the stress increase is slower, indicating that high content composite material can buffer thermal expansion, but excessive content may hinder the conductive path; the optimal ratio is 1.2:1 to 1.4:1, which can achieve the best balance between sheet resistance and stress increase.

[0055] As shown in Examples 1 and 6-8, among the MOF metal elements (Cu / Fe / Ni / Co), the electrical conductivity is as follows: the Cu-MOF / rGO system has the lowest sheet resistance because its d-electron orbital characteristics are more conducive to carrier migration; the Fe-MOF / rGO system is second, and the Ni / Co system is slightly higher, possibly related to the difference in redox activity of metal ions. Thermal stability: the Cu system shows a significant increase in stress after heating, while the Co-MOF / rGO system shows the smallest increase in stress, indicating that the coordination structure of Co is more resistant to thermal expansion stress. As can be seen from Examples 1 and Comparative Examples 1 and 2, in the comparison of ligands, the coating adhesion is as follows: the peel force of the aspartic acid ligand is always higher than 1500 N / m, and it is still >1300 N / m after 30 days of immersion. However, the 2-methylimidazole coating of Comparative Example 1 and the terephthalic acid coating of Comparative Example 2 completely peel off within 15 days. The carboxyl group of aspartic acid has a stronger interface binding with rGO. The use of terephthalic acid and 2-methylimidazole can easily lead to the failure of the coating-base film interface.

[0056] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Any simple modifications, equivalent substitutions, and improvements made by those skilled in the art to the above embodiments without departing from the scope of the technical solution of the present invention, based on the technical essence of the present invention, shall still fall within the protection scope of the technical solution of the present invention.

Claims

1. A functional current collector for improving thermal stability, characterized in that, include: A polymer substrate layer, wherein the polymer substrate layer contains a negative thermal expansion material; An alumina underlayer is disposed on both sides of a polymer substrate layer; An aluminum metal coating, wherein the aluminum metal coating is disposed on both sides of an aluminum oxide underlayer; The negative thermal expansion material is an X-MOF / rGO composite material, wherein X is selected from any one of Cu, Fe, Ni, and Co; and the ligand of MOF is aspartic acid.

2. The functional current collector for improving thermal stability according to claim 1, characterized in that: The thickness of the polymer substrate is 4~10μm.

3. A method for preparing a functional current collector with improved thermal stability, characterized in that, Includes the following steps: S1: Prepare a polymeric substrate layer containing a negative thermal expansion material; S2: Prepare an alumina underlayer on both sides of the polymer substrate layer; S3: Prepare aluminum metal coatings on both sides of the aluminum oxide underlayer; The method for preparing the polymer substrate layer containing negative thermal expansion material in step S1 is as follows: S1.1: Mix a compound containing Cu, Fe, Ni or Co with aspartic acid and a base; S1.2: The mixture from step S1.1 is mixed with an excess of rGO suspension to obtain an X-MOF / rGO composite material, where X is selected from Cu, Fe, Ni, and Co. S1.3: After mixing the X-MOF / rGO composite material with the polymer material, the mixture is stretched, shaped and slit to obtain a polymer base layer containing negative thermal expansion material.

4. The method for preparing a functional current collector with improved thermal stability according to claim 3, characterized in that: The compound containing Cu, Fe, Ni or Co mentioned in step S1.1 is a nitrate.

5. The method for preparing a functional current collector with improved thermal stability according to claim 3, characterized in that: In step S1.1, the mass ratio of the compound containing Cu, Fe, Ni, or Co to aspartic acid and the base is 5~7:2:0.5~1.

5.

6. The method for preparing a functional current collector with improved thermal stability according to claim 3, characterized in that: Step S1.1 The compound containing Cu, Fe, Ni or Co is mixed with aspartic acid and a base, and then water is added to make the solid-liquid ratio 2.5~3.5:

1. The mixture is stirred and filtered to obtain a mixed product.

7. The method for preparing a functional current collector with improved thermal stability according to claim 3, characterized in that: In step S1.3, the mixing mass ratio of the X-MOF / rGO composite material to the polymer material is 1.2~1.4:

1.

8. The method for preparing a functional current collector with improved thermal stability according to claim 3, characterized in that: In step S1.3, the heating temperature used for shaping is 190~210℃, the time is 3~6 seconds, and after shaping, it is air-cooled to 45~55℃.

9. An electrode sheet, characterized in that: The present invention comprises the functional current collector with improved thermal stability as described in claim 1 or 2, or the functional current collector with improved thermal stability prepared by the method described in any one of claims 3 to 8.

10. A battery, characterized in that: It includes the electrode sheet as described in claim 9.

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