Battery cell based on composite current collector, preparation method of battery cell, electrochemical device and electronic device

Abstract

The invention relates to a battery cell based on a composite current collector, a preparation method of the battery cell, an electrochemical device and an electronic device, and belongs to the technical field of methods or devices for directly converting chemical energy into electric energy. The preparation method of the battery cell based on the composite current collector comprises the following steps: S1, welding a metal foil on the surface of one side of the composite current collector in a blank area of a pole piece by adopting ultrasonic roll welding to obtain the pole piece with a metal foil tab; s2, winding the pole piece with the metal foil tab in the step S1 and other battery cell components to form a bare roll core, performing ultrasonic opposite rolling welding on a blank area of the tab in the winding process, and enabling the metal foil tab to be in contact with the surface of the other side of the composite current collector after welding; and S3, carrying out tab welding, packaging and liquid injection on the bare roll core in the S2 to obtain the battery cell. According to the method, double-sided metal film conduction of the composite current collector can be realized under the condition that the overall thickness of the tab is not increased, so that the energy density of the battery cell is improved.

Description

Technical Field

[0001] This invention relates to the field of methods or devices for directly converting chemical energy into electrical energy, and particularly to a battery cell based on a composite current collector, its preparation method, an electrochemical device, and an electronic device. Background Technology

[0002] Currently, most current collectors in new energy batteries are metal current collectors. However, metal current collectors do not provide energy during battery operation, and they account for about 15% of the weight of the battery module, severely restricting the improvement of battery energy density. Furthermore, due to the poor flexibility of metal current collectors, they are prone to wrinkling and breakage during battery manufacturing. Moreover, metal current collectors have lower safety; when a short circuit occurs inside the battery, it can easily lead to internal self-discharge and subsequent thermal runaway.

[0003] To address these issues, composite current collectors, consisting of a polymer film and a metal coating, have been introduced to replace conventional metal current collectors. However, the polymer film forms the middle layer of the composite current collector, preventing the metal coatings on both sides of the polymer film from conducting, thus affecting the battery's high-rate charge and discharge capabilities. Current technology typically uses two layers of metal foil to sandwich the tab portion of the composite current collector for welding. While this method achieves conductivity between the metal coatings on both sides of the composite current collector, it significantly increases the overall thickness of the tab, hindering subsequent tab connection welding and easily leading to problems such as tab tearing and incomplete soldering, thus affecting the tab's overcurrent capacity and internal resistance. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of the prior art and provide a battery cell based on a composite current collector, its preparation method, electrochemical device, and electronic device.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows: In a first aspect, the present invention provides a method for preparing a battery cell based on a composite current collector, comprising the following steps: S1. Using ultrasonic roll welding, metal foil is welded to the surface of the composite current collector side in the blank area of ​​the electrode sheet to obtain an electrode sheet with metal foil tabs; the electrode sheet is a positive electrode sheet and / or a negative electrode sheet; S2. The electrode sheet with metal foil tabs described in S1 is made into a bare core by winding with other battery cell components. During the winding process, the blank area of ​​the electrode sheet is ultrasonically rolled and welded. After welding, the metal foil tabs are in contact with the surface on the other side of the composite current collector. S3. The bare core described in S2 is subjected to tab welding, encapsulation, and electrolyte injection to obtain a battery cell.

[0006] This invention employs ultrasonic roll welding to weld metal foil onto the surface of the composite current collector side in the blank area of ​​the electrode sheet to achieve single-sided tab lead-out. The electrode sheet and separator are wound into a bare core by winding. During the winding process, a second ultrasonic roll welding is performed on the blank area of ​​the core tab to make the metal film at the tab of the adjacent composite current collector layer conduct on both sides. This achieves double-sided conduction of the composite current collector without increasing the tab thickness, which can improve the energy density and high-rate charge and discharge performance of the battery, and also achieve continuous and efficient tab welding, improving production line efficiency. At the same time, the tab welding process can also improve the tearing and cold solder joint of the tab.

[0007] Meanwhile, the inventors discovered that, compared to other welding methods (such as spot welding or laser welding), ultrasonic roller welding can better adapt to the structural characteristics of composite current collectors, and can better achieve interlayer conductive connection of composite current collectors and continuous welding of electrode tabs and current collectors by using "continuous rolling + high-frequency vibration".

[0008] The blank area of ​​the electrode sheet in step S1 refers to a blank area left in the width direction of the electrode sheet where the positive or negative electrode paste is not coated. This area is the foil electrode tab, which is used for subsequent electrode tab welding.

[0009] The composite current collector in step S1 includes a first metal foil layer, a polymer layer, and a second metal foil layer that are sequentially stacked and bonded together; wherein, the polymer layer is selected from any one of polyethylene terephthalate (PET), polypropylene (PP), and polyimide (PI); and the first metal foil layer and the second metal foil layer are copper or aluminum.

[0010] In a preferred embodiment of the method for preparing a battery cell based on a composite current collector according to the present invention, the width of the metal foil in step S1 is 'a', and the width of the blank area of ​​the electrode sheet is 'b', where 5mm ≤ ab ≤ 20mm. For example, ab can be, but is not limited to, 5mm, 6mm, 7mm, 8mm, 9mm, 10mm, 11mm, 12mm, 13mm, 14mm, 15mm, 16mm, 17mm, 18mm, 19mm, or 20mm, or fall within any two of the above values. By controlling the difference (ab) between the width of the metal foil and the width of the blank area of ​​the electrode sheet to be within the above range, it is more beneficial to the subsequent electrode tab welding to better ensure welding strength, while also avoiding the influence of redundant electrode tabs on subsequent assembly.

[0011] In a preferred embodiment of the method for preparing a battery cell based on a composite current collector according to the present invention, the width of the welding head in the ultrasonic roll welding in step S1 is c, and the width of the blank area of ​​the electrode sheet is b, where 1mm ≤ cb ≤ 2mm. For example, cb can be, but is not limited to, 1mm, 1.1mm, 1.2mm, 1.3mm, 1.4mm, 1.5mm, 1.6mm, 1.7mm, 1.8mm, 1.9mm, or 2mm, or fall within any two of the above values. By adjusting the difference (cb) between the width of the welding head and the width of the blank area of ​​the electrode sheet in the ultrasonic roll welding to be within the above range, it is not only more beneficial to improve the firmness of the roll welding to reduce the risk of metal foil detachment, but also to better ensure the consistency of the welding effect.

[0012] In a preferred embodiment of the method for preparing a battery cell based on a composite current collector according to the present invention, the thickness of the metal foil in step S1 is 4 μm to 8 μm, for example, but not limited to 4 mm, 4.2 mm, 4.4 mm, 4.6 mm, 4.8 mm, 5 mm, 5.2 mm, 5.4 mm, 5.6 mm, 5.8 mm, 6 mm, 6.2 mm, 6.4 mm, 6.6 mm, 6.8 mm, 7 mm, 7.2 mm, 7.4 mm, 7.6 mm, 7.8 mm or 8 mm, or within the range of any two of the above values.

[0013] In a preferred embodiment of the method for preparing a battery cell based on a composite current collector according to the present invention, the width of the blank area of ​​the electrode sheet in step S1 is 3mm to 20mm, for example, but not limited to 3mm, 4mm, 5mm, 6mm, 7mm, 8mm, 9mm, 10mm, 11mm, 12mm, 13mm, 14mm, 15mm, 16mm, 17mm, 18mm, 19mm or 20mm, or within the range of any two of the above values.

[0014] In a preferred embodiment of the method for preparing a battery cell based on a composite current collector according to the present invention, during ultrasonic rolling welding in step S1, the metal foil is aligned with the blank area of ​​the electrode sheet and the deviation of the rolling weld mark from the edge is controlled within ±0.2mm.

[0015] In a preferred embodiment of the method for preparing a battery cell based on a composite current collector according to the present invention, the metal foil in step S1 is any one of copper foil, aluminum foil, copper-nickel alloy foil, and aluminum-manganese alloy foil.

[0016] Secondly, the present invention provides a battery cell prepared by the above-described preparation method.

[0017] Thirdly, the present invention provides an electrochemical device comprising the aforementioned battery cell.

[0018] Fourthly, the present invention provides an electronic device comprising the electrochemical device described above.

[0019] Compared with the prior art, the beneficial effects of the present invention are as follows: This invention employs ultrasonic roll welding to weld metal foil onto the surface of the composite current collector side in the blank area of ​​the electrode sheet to achieve single-sided tab lead-out. The electrode sheet and separator are wound into a bare core by winding. During the winding process, a second ultrasonic roll welding is performed on the blank area of ​​the core tab to make the metal film at the tab of the adjacent composite current collector layer conduct on both sides. This achieves double-sided conduction of the composite current collector without increasing the tab thickness, which can improve the energy density and high-rate charge and discharge performance of the battery, and also achieve continuous and efficient tab welding, improving production line efficiency. At the same time, the tab welding process can also improve the tearing and cold solder joint of the tab. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of ultrasonic roller welding in step S1 of Example 1; Figure 2 This is a schematic diagram of the electrode travel direction during ultrasonic rolling welding in step S1 of Example 1; Figure 3 This is a schematic diagram of the cross-sectional structure of the electrode sheet obtained after step S1 of Example 1; Figure 4 This is a schematic diagram of the structure of the bare core obtained after step S2 of Example 1.

[0021] Explanation of reference numerals in the attached figures: 1. Active material layer; 2. Metal foil layer of composite current collector; 3. Polymer layer of composite current collector; 4. Metal foil material. Detailed Implementation

[0022] To better illustrate the purpose, technical solution, and advantages of the present invention, the present invention will be further described below in conjunction with specific embodiments.

[0023] Unless otherwise specified, all other materials and reagents used in the examples are commercially available.

[0024] Example 1 <Preparation of the positive electrode> The positive electrode active material (LiMn) 0.6 Fe 0.4PO4, binder (polyvinylidene fluoride) and conductive agent (acetylene black) are added to N-methylpyrrolidone (NMP) in a mass ratio of 97:1.5:1.5 and mixed evenly to obtain a positive electrode slurry. The positive electrode slurry is then coated onto an aluminum foil with a thickness of 12μm. During coating, care should be taken to leave a 10±1mm area in the width direction as a blank area for the electrode sheet. The foil is then vacuum dried at 100℃, rolled and sliced ​​to obtain the positive electrode sheet.

[0025] <Preparation of Negative Electrode Sheets> The negative electrode active material (graphite), binder (polyvinylidene fluoride) and conductive agent (acetylene black) are added to deionized water at a mass ratio of 92:4:4 and mixed evenly to obtain a negative electrode slurry. Then, the negative electrode slurry is coated onto a composite current collector (copper film layer (1μm) / PET layer (2.5μm) / copper film layer (1μm)) with a thickness of 4.5μm. When coating, it is necessary to leave a 4±1mm area in the width direction as a blank area for the electrode sheet. The electrode sheet is then vacuum dried at 100℃, rolled and sliced ​​to obtain the negative electrode sheet.

[0026] <Preparation of Electrolyte> The electrolyte is 1 mol / L LiPF6, in which the solvent is composed of ethylene carbonate (EC), ethyl methyl carbonate (DMC), and methyl ethyl carbonate (EMC) in a volume ratio of EC:DMC:EMC=3:3:4.

[0027] <Preparation of the diaphragm> The diaphragm is a PE diaphragm with a thickness of 12μm.

[0028] <Cell Fabrication> S1. Using ultrasonic roll welding, metal foil (4.5μm thick copper foil) is welded to the surface of the composite current collector side in the blank area of ​​the negative electrode sheet (e.g., Figure 1 and Figure 2 As shown), an electrode sheet with metal foil tabs is obtained (e.g. Figure 3 (as shown) The width of the metal foil is 18±1mm, the width of the ultrasonic roller welding head is 5mm, and the metal foil must be aligned with the blank area of ​​the electrode during roller welding to avoid missed welding and misaligned welding. The deviation between the roller welding mark and the edge must be controlled within ±0.2mm. At the same time, an additional CCD (charge-coupled device) online detection system is used to monitor the roller welding status to meet the requirements of welding accuracy and consistency. S2. The negative electrode sheet with metal foil tabs from S1, the aforementioned positive electrode sheet, and the separator are wound together to form a bare core. During the winding process, the blank areas of the electrode sheet are ultrasonically rolled together. After welding, the metal foil tabs contact the surface on the other side of the composite current collector (e.g., Figure 4 (as shown) S3. The bare core from S2 is subjected to a short-circuit test (test voltage is 50V to 350V). After passing the test, the metal foil tabs outside the roll-welded area are welded to the current collector. Then, the encapsulation process is carried out. After sealing, the sealing performance needs to be tested. If the sealing performance meets the requirements, the process is transferred to the baking process. After baking, the electrolyte is injected (the electrolyte is the one mentioned above). Then, aging, formation, capacity testing and OCV voltage screening are carried out to obtain the battery cell.

[0029] Example 2 Except for the preparation of the positive electrode, the negative electrode, and the battery cell, which are different from those in Example 1, the rest are the same as in Example 1.

[0030] <Preparation of the positive electrode> The positive electrode active material (LiMn) 0.6 Fe 0.4 PO4, binder (polyvinylidene fluoride) and conductive agent (acetylene black) are added to N-methylpyrrolidone (NMP) in a mass ratio of 97:1.5:1.5 and mixed evenly to obtain a positive electrode slurry. Then, the positive electrode slurry is coated onto a composite current collector (aluminum film layer (1μm) / PET layer (4.5μm) / aluminum film layer (1μm)) with a thickness of 6.5μm. When coating, it is necessary to leave a 5±1mm area in the width direction as a blank area for the electrode. The electrode is vacuum dried at 100℃, rolled and sliced ​​to obtain the positive electrode sheet.

[0031] <Preparation of Negative Electrode Sheets> The negative electrode active material (graphite), binder (polyvinylidene fluoride) and conductive agent (acetylene black) are added to deionized water at a mass ratio of 92:4:4 and mixed evenly to obtain a negative electrode slurry. The negative electrode slurry is then coated onto a copper foil with a thickness of 6.5 μm. During coating, care should be taken to leave a 4±1 mm area in the width direction as a blank area for the electrode sheet. The electrode sheet is then vacuum dried at 100℃, rolled, and sliced ​​to obtain the negative electrode sheet.

[0032] <Cell Fabrication> S1. Using ultrasonic rolling welding, metal foil (aluminum foil with a thickness of 6μm) is welded to the surface of the composite current collector side in the blank area of ​​the positive electrode sheet to obtain an electrode sheet with metal foil tabs. The width of the metal foil is 15±1mm, the width of the ultrasonic roller welding head is 5mm, and the metal foil must be aligned with the blank area of ​​the electrode during roller welding to avoid missed welding and misaligned welding. The deviation between the roller welding mark and the edge must be controlled within ±0.2mm. At the same time, an additional CCD (charge-coupled device) online detection system is used to monitor the roller welding status to meet the requirements of welding accuracy and consistency. S2. The positive electrode sheet with metal foil tabs in S1, the negative electrode sheet and the separator are made into a bare core by winding. During the winding process, the blank area of ​​the electrode sheet is ultrasonically rolled and welded. After welding, the metal foil tabs are in contact with the surface on the other side of the composite current collector. S3. The bare core from S2 is subjected to a short-circuit test (test voltage is 50V to 350V). After passing the test, the metal foil tabs outside the roll-welded circuit are welded to the current collector. Then, the encapsulation process is carried out. After sealing, the sealing performance needs to be tested. If the sealing performance meets the requirements, the process is transferred to the baking process. After baking, the electrolyte is injected. Then, aging, formation, capacity testing and OCV voltage screening are carried out to obtain the battery cell.

[0033] Example 3 Except for the positive electrode active material in "Preparation of Positive Electrode Sheet" which is ternary (LiNi) 0.8 Mn 0.1 Co 0.1 O2), the rest is the same as in Example 1.

[0034] Example 4 Except for the positive electrode active material in "Preparation of Positive Electrode Sheet" which is ternary (LiNi) 0.8 Mn 0.1 Co 0.1 O2), the rest is the same as in Example 2.

[0035] Example 5 Except for the preparation of the positive electrode, the negative electrode, and the battery cell, which are different from those in Example 1, the rest are the same as in Example 1.

[0036] <Preparation of the positive electrode> The positive electrode active material (LiMn) 0.6 Fe 0.4 PO4, binder (polyvinylidene fluoride) and conductive agent (acetylene black) are added to N-methylpyrrolidone (NMP) in a mass ratio of 97:1.5:1.5 and mixed evenly to obtain a positive electrode slurry. Then, the positive electrode slurry is coated onto a composite current collector (aluminum film layer (1μm) / PET layer (4.5μm) / aluminum film layer (1μm)) with a thickness of 6.5μm. When coating, it is necessary to leave a 5±1mm area in the width direction as a blank area for the electrode. The electrode is vacuum dried at 100℃, rolled and sliced ​​to obtain the positive electrode sheet.

[0037] <Preparation of Negative Electrode Sheets> The negative electrode active material (graphite), binder (polyvinylidene fluoride) and conductive agent (acetylene black) are added to deionized water at a mass ratio of 92:4:4 and mixed evenly to obtain a negative electrode slurry. Then, the negative electrode slurry is coated onto a composite current collector (copper film layer (1μm) / PET layer (2.5μm) / copper film layer (1μm)) with a thickness of 4.5μm. When coating, it is necessary to leave a 4±1mm area in the width direction as a blank area for the electrode sheet. The electrode sheet is then vacuum dried at 100℃, rolled and sliced ​​to obtain the negative electrode sheet.

[0038] <Cell Fabrication> S1. Using ultrasonic rolling welding, a metal foil (copper foil with a thickness of 4.5μm) is welded to the surface of the composite current collector side in the blank area of ​​the negative electrode sheet to obtain an electrode sheet with metal foil tabs (the width of the metal foil is 18±1mm). Ultrasonic rolling welding is used to weld metal foil (aluminum foil with a thickness of 6μm) onto the surface of the composite current collector side in the blank area of ​​the positive electrode sheet to obtain an electrode sheet with metal foil tabs (the width of the metal foil is 15±1mm). The ultrasonic roller welding head is 5mm wide. During roller welding, the metal foil must be aligned with the blank area of ​​the electrode to avoid missed welding and misalignment. The deviation between the roller welding mark and the edge must be controlled within ±0.2mm. At the same time, an additional CCD (charge-coupled device) online detection system is used to monitor the roller welding status to meet the requirements of welding accuracy and consistency. S2. The negative electrode sheet with metal foil tabs, the positive electrode sheet with metal foil tabs and the separator in S1 are made into a bare core by winding. During the winding process, the blank area of ​​the electrode sheet is ultrasonically rolled and welded. After welding, the metal foil tabs are in contact with the surface on the other side of the composite current collector. S3. The bare core from S2 is subjected to a short-circuit test (test voltage is 50V to 350V). After passing the test, the metal foil tabs outside the roll-welded circuit are welded to the current collector. Then, the encapsulation process is carried out. After sealing, the sealing performance needs to be tested. If the sealing performance meets the requirements, the process is transferred to the baking process. After baking, the electrolyte is injected. Then, aging, formation, capacity testing and OCV voltage screening are carried out to obtain the battery cell.

[0039] Example 6 Except for the positive electrode active material in "Preparation of Positive Electrode Sheet" which is ternary (LiNi) 0.8 Mn 0.1 Co 0.1 O2), the rest is the same as in Example 5.

[0040] Comparative Example 1 Except for the preparation of the negative electrode sheet, which differs from Example 1, the rest is the same as Example 1.

[0041] <Preparation of Negative Electrode Sheets> The negative electrode active material (graphite), binder (polyvinylidene fluoride) and conductive agent (acetylene black) are added to deionized water at a mass ratio of 92:4:4 and mixed evenly to obtain a negative electrode slurry. The negative electrode slurry is then coated onto a copper foil with a thickness of 6.5 μm. During coating, care should be taken to leave a 4±1 mm area in the width direction as a blank area for the electrode sheet. The electrode sheet is then vacuum dried at 100℃, rolled, and sliced ​​to obtain the negative electrode sheet.

[0042] Comparative Example 2 Except for the <Preparation of Battery Cells>, which differs from Example 1, the rest is the same as Example 1.

[0043] <Cell Fabrication> S1. Using ultrasonic rolling welding, two layers of metal foil (copper foil with a thickness of 4.5μm) are welded to the surfaces on both sides of the composite current collector in the blank area of ​​the above negative electrode sheet to obtain an electrode sheet with two layers of metal foil tabs. The width of the metal foil is 18±1mm, the width of the ultrasonic roller welding head is 5mm, and the metal foil must be aligned with the blank area of ​​the electrode during roller welding to avoid missed welding and misaligned welding. The deviation between the roller welding mark and the edge must be controlled within ±0.2mm. At the same time, an additional CCD (charge-coupled device) online detection system is used to monitor the roller welding status to meet the requirements of welding accuracy and consistency. S2. The negative electrode sheet with two layers of metal foil tabs in S1, the above-mentioned positive electrode sheet and the separator are made into a bare core by winding. S3. The bare core from S2 is subjected to a short-circuit test (test voltage is 50V to 350V). After passing the test, the metal foil tabs outside the roll-welded area are welded to the current collector. Then, the encapsulation process is carried out. After sealing, the sealing performance needs to be tested. If the sealing performance meets the requirements, the process is transferred to the baking process. After baking, the electrolyte is injected (the electrolyte is the one mentioned above). Then, aging, formation, capacity testing and OCV voltage screening are carried out to obtain the battery cell.

[0044] The performance of the battery cells prepared in each embodiment and comparative example is shown in Table 1.

[0045] 1) Mass energy density test method: The battery energy density test method shall be performed in accordance with GB / T 31467-2023 "Test Method for Electrical Performance of Lithium-ion Power Battery Packs and Systems for Electric Vehicles".

[0046] 2) Internal resistance test method: The battery internal resistance test is conducted according to the battery internal resistance test method in GB / T 31467-2023 "Test Method for Electrical Performance of Lithium-ion Power Battery Packs and Systems for Electric Vehicles", with a temperature of 25℃ and a SOC of 50%.

[0047] Table 1 According to the data in Table 1, the mass energy density of the cells in Examples 1 to 6 reaches over 221 Wh / kg, while the internal resistance is less than or equal to 0.60 mΩ. This indicates that the method for preparing the cell based on the composite current collector of the present invention can achieve double-sided metal film conductivity of the composite current collector without increasing the overall thickness of the electrode tab, thus enabling the cell to have high energy density and low internal resistance. Furthermore, according to Examples 1, Comparative Examples 1 and 2, it can also be found that replacing the metal current collector with a composite current collector and using two layers of metal foil to sandwich a layer of composite current collector for welding, although it can also improve the mass energy density of the cell, the improvement effect is limited and it increases the internal resistance of the cell.

[0048] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the essence and scope of the technical solutions of the present invention.

Claims

1. A method of making a composite current collector based cell, characterized by, The method comprises the following steps: S1, using ultrasonic butt welding to weld the metal foil on the surface of one side of the composite current collector in the blank area of the pole piece to obtain a pole piece with a metal foil tab; the pole piece is a positive pole piece and / or a negative pole piece; S2, the pole piece with a metal foil tab in S1 and other cell components are wound to form a bare roll core, and ultrasonic butt welding is performed on the blank area of the pole piece during winding; after welding, the metal foil tab is in contact with the surface of the other side of the composite current collector; S3, the bare roll core in S2 is tab welded, packaged, and liquid injected to obtain a cell.

2. The production method according to claim 1, wherein In step S1, the width of the metal foil is a, and the width of the blank area of the pole piece is b, 5mm≤a-b≤20mm.

3. The production method according to claim 1, wherein In step S1, the width of the welding head of the ultrasonic butt welding is c, and the width of the blank area of the pole piece is b, 1mm≤c-b≤2mm.

4. The production method according to any one of claims 1 to 3, wherein In step S1, the thickness of the metal foil is 4μm to 8μm.

5. The production method according to any one of claims 1 to 3, wherein In step S1, the width of the blank area of the pole piece is 3mm to 20mm.

6. The production method according to claim 1, wherein In step S1, during ultrasonic butt welding, the metal foil is aligned with the blank area of the pole piece, and the deviation of the rolling weld mark from the edge is controlled within ±0.2mm.

7. The production method according to claim 1, wherein In step S1, the metal foil is any one of copper foil, aluminum foil, copper-nickel alloy foil, and aluminum-manganese alloy foil.

8. The cell prepared by the method of any one of claims 1 to 7.

9. An electrochemical device, characterized by, The cell of claim 8.

10. An electronic device, comprising: The electrochemical device of claim 9.

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