Positive pole piece and battery
By forming an unevenly distributed aluminum oxide layer on the aluminum film and coating the graphene oxide layer, the bonding force between the conductive material and the aluminum film is improved by using physical force, the problem of easy fall off of the conductive material is solved, reducing costs and improving battery life.
Patent Information
- Application Number
- CN202420655150.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-04-01
- Publication Date
- 2025-05-02
- Estimated Expiration
- 2034-04-01
AI Technical Summary
In the prior art, the conductive active material coated on the aluminum film is prone to fall off, and other auxiliary materials such as binders are used, resulting in higher costs and reduced battery performance.
By forming an unevenly distributed aluminum oxide layer on the aluminum film and uniformly coating the graphene oxide layer on its surface, the binding force of the conductive material and the aluminum film is improved by relying on the physical action force between metal aluminum and graphene oxide, as well as the alumina and graphene oxide.
It effectively solves the problem that conductive active materials are prone to fall off, reduces the degradation of battery performance caused by adhesives, reduces production costs, and improves the service life of the battery.
Smart Images
Figure CN222826426U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the technical field of vacuum coating, in particular to a positive electrode sheet and a battery. Background Art
[0002] Aluminum film refers to a film with aluminum material on the surface, which can be either pure aluminum foil or composite aluminum foil. Currently, aluminum foil or composite aluminum foil is used in many types of batteries, mainly by coating active conductive materials on aluminum film to form positive electrode sheets. However, the current coating process of coating active conductive materials on aluminum film is mostly complicated, and other auxiliary materials such as adhesives are used. In addition, the active conductive materials coated on the aluminum film in this way are easy to fall off, and the cost is relatively high. Utility Model Content
[0003] In view of this, the purpose of the embodiments of the utility model is to provide a positive electrode plate and a battery to solve the problem that the conductive active material coated on the aluminum film in the prior art is easy to fall off.
[0004] In order to achieve the above-mentioned object, the embodiment of the utility model provides a positive electrode sheet, and the positive electrode sheet comprises:
[0005] An aluminum film, an aluminum oxide layer with holes arranged on the surface of the aluminum film, and a graphene oxide layer arranged on the surface of the oxide layer.
[0006] In some possible implementations, the aluminum oxide layer is formed by subjecting the aluminum film to alkaline corrosion treatment with an alkaline etching solution and then forming a discontinuously distributed aluminum oxide layer on the surface of the aluminum film.
[0007] In some possible implementations, the aluminum oxide layer has a thickness of 10 nm to 100 nm.
[0008] In some possible implementations, the thickness of the aluminum film is 3 um to 8 um.
[0009] In some possible implementations, the graphene oxide layer has a thickness of 10 nm to 2 um.
[0010] In some possible implementations, the aluminum film is pure aluminum foil or composite aluminum foil.
[0011] In some possible implementations, the composite aluminum foil includes an insulating layer and aluminum layers disposed on both sides of the insulating layer.
[0012] In some possible implementations, the insulating layer is made of at least one of PP film, PE film and PET film.
[0013] In a second aspect, an embodiment of the utility model further provides a battery, wherein the battery comprises any one of the positive electrode plates described above.
[0014] The beneficial technical effects of the above technical solution are:
[0015] The utility model provides a positive electrode plate and a battery, the positive electrode plate comprising: an aluminum film, an aluminum oxide layer unevenly distributed on the surface of the aluminum film, and a graphene oxide layer uniformly arranged on the surface of the oxide layer. The utility model relies on the physical force between metal aluminum and graphene oxide, and between aluminum oxide and graphene oxide to improve the bonding force between the conductive material and the aluminum film, instead of using a binder to improve the bonding force, thereby solving the problem of easy detachment of the conductive active material coated on the aluminum film in the prior art, and also reducing the problem of battery performance degradation caused by the binder. BRIEF DESCRIPTION OF THE DRAWINGS
[0016] In order to more clearly illustrate the embodiments of the utility model or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the utility model. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.
[0017] Figure 1 This is a schematic diagram of the overall structure of a positive electrode sheet provided in this practical embodiment;
[0018] Figure 2 It is a schematic diagram of the structure of the aluminum film after alkali corrosion in the embodiment of the utility model;
[0019] Figure 3 It is a structural schematic diagram of a composite aluminum foil according to an embodiment of the utility model.
[0020] Description of Figure Numbers:
[0021] 1. Aluminum film; 2. Aluminum oxide layer; 3. Graphene oxide layer; 11. Insulating layer; 12. Aluminum layer. DETAILED DESCRIPTION
[0022] The features and exemplary embodiments of various aspects of the utility model will be described in detail below. In the detailed description below, many specific details are proposed in order to provide a comprehensive understanding of the utility model. However, it is obvious to those skilled in the art that the utility model can be implemented without the need for some of these specific details. The following description of the embodiment is only to provide a better understanding of the utility model by illustrating an example of the utility model. In the drawings and the following description, at least part of the known structures and technologies are not shown in order to avoid unnecessary ambiguity to the utility model; and, for clarity, the size of some structures may be exaggerated. In addition, the features, structures or characteristics described below may be combined in one or more embodiments in any suitable manner.
[0023] Figure 1 is a schematic diagram of the overall structure of a positive electrode sheet provided in this practical embodiment, such as Figure 1 As shown, the positive electrode plate includes: an aluminum film 1, an aluminum oxide layer 2 with holes arranged on the surface of the aluminum film 1, and a graphene oxide layer 3 arranged on the surface of the aluminum oxide layer 2. Optionally, the graphene oxide layer 3 is uniformly arranged on the surface of the aluminum oxide layer 2.
[0024] Specifically, in the present embodiment, a loose natural aluminum oxide layer 2 with holes is provided on the aluminum film 1, and a graphene oxide layer 3 is provided on the aluminum oxide layer 2. Through the cooperation of the graphene oxide and aluminum oxide, the graphene oxide coated on the aluminum film 1 is not easy to fall off. Because both graphene oxide and aluminum oxide are negatively charged and aluminum metal is positively charged, the loose natural aluminum oxide on the surface of the aluminum film 1 can produce hydrogen bonds with the oxygen-containing functional groups on the surface of the graphene oxide. The aluminum oxide can also protect the internal metallic aluminum, making it not easily corroded and reacted in the electrolyte. The place where the natural aluminum oxide on the surface of the aluminum foil is missing will expose a part of the positively charged aluminum metal. There is a force between the aluminum metal and the graphene oxide, which greatly enhances the bonding force between the graphene oxide and the aluminum film 1.
[0025] This embodiment relies on the physical forces between metallic aluminum and graphene oxide, and between aluminum oxide and graphene oxide to improve the bonding strength between the conductive material and the aluminum film 1, rather than using an adhesive to improve the bonding strength. This solves the problem in the prior art that the conductive active material coated on the aluminum film 1 is easy to fall off, and also reduces the problem of battery performance degradation caused by the adhesive.
[0026] In some embodiments, the aluminum oxide layer 2 is a natural aluminum oxide layer 2 that is discontinuously distributed and formed on the surface of the aluminum film 1 after the aluminum film 1 is subjected to alkaline etching treatment with an alkaline etching solution.
[0027] Figure 2Schematic diagram of the structure of the aluminum film 1 after alkali corrosion in the embodiment of the utility model. Figure 2 As shown, in this embodiment, after the aluminum film 1 is treated with alkaline etching, a natural aluminum oxide layer 2 will be formed in the air. The naturally formed aluminum oxide film 1 is thin and porous, and is distributed discontinuously on the surface of the aluminum foil. Specifically, the surface of the aluminum film 1 has uneven pits and protrusions left after being treated with alkali solution. Aluminum oxide is arranged in the pits, while there is no aluminum oxide at the protrusions or the thickness of the aluminum oxide should be thinner than the aluminum oxide in the pits. Because the aluminum oxide at the protrusions is easy to fall off, the aluminum oxide layer 2 is more formed at the pits, and the protrusions are thinner or even have no aluminum oxide film 1. Therefore, this naturally formed aluminum oxide layer 2 is very thin and not dense (i.e., thin and porous), and is unevenly distributed on the surface of the aluminum foil. The metal aluminum foil will be exposed where the aluminum oxide layer 2 is not formed or the aluminum oxide at the protrusions falls off. In addition, after the aluminum film 1 is treated with alkaline corrosion, graphene oxide needs to be directly coated on its surface, and the graphene oxide is evenly coated on the surface of the corroded aluminum film 1 to form a graphene oxide layer 3, so as to reduce the contact time between the aluminum foil and the air and avoid the generation of more, thicker and uneven aluminum oxide films.
[0028] In this embodiment, since graphene oxide and aluminum oxide are negatively charged, aluminum metal is positively charged, and the structure of natural aluminum oxide itself is porous and similar to a honeycomb structure, the loose natural aluminum oxide on the surface of the aluminum film 1 can produce hydrogen bonds with the oxygen-containing functional groups on the surface of graphene oxide, and graphene oxide is negatively charged. The uneven and porous aluminum oxide on the surface of the aluminum foil will expose a portion of positively charged aluminum metal, and there may be an interaction between them to enhance the bonding strength of graphene oxide and alkaline-etched aluminum foil. In addition, the surface of the corroded aluminum film 1 has a certain degree of roughness, which can further increase the adhesion of the active material graphene oxide on the surface of the aluminum film 1.
[0029] In this embodiment, the aluminum film 1 is coated with the conductive material graphene oxide after being alkali-etched, which can avoid the problem of directly mixing the alkali-etching reagent into the conductive material and the produced gas penetrating the aluminum foil. In addition, the conductive material on the surface of the alkali-etched aluminum film 1 is evenly distributed, which can effectively inhibit the formation of lithium dendrites during the charging and discharging process of the lithium battery and improve the battery life.
[0030] Optionally, the thickness of the aluminum oxide layer 2 can be 10nm to 100nm, specifically, the thickness of the aluminum oxide layer 2 is 10nm or 20nm or 30nm or 80nm or 100nm, or any value between 10nm and 2um. The thickness of the aluminum film 1 can be 3um to 8um, specifically, the thickness of the aluminum film 1 is 4um or 5um or 6um or 7um, etc., or any value between 3um and 8um. The thickness of the graphene oxide layer 3 can be 10nm to 2um. Specifically, the thickness of the graphene oxide layer 3 is 10nm or 20nm or 30nm or 80nm or 100nm or 200nm or 500nm or 1um or 1.5um, or any value between 10nm and 2um.
[0031] In some embodiments, the alkaline etching solution includes 20-30 g / L Na2CO3, 10-20 g / L NaOH and pure water. Since the solvent used in this embodiment is water or ethanol solution, the cost is lower than that of solvents such as NMP or isopropanol used in the prior art.
[0032] In some embodiments, the aluminum film 1 is pure aluminum foil or composite aluminum foil. Figure 3 Schematic diagram of the structure of a composite aluminum foil of the utility model embodiment. Figure 3 As shown, the composite aluminum foil includes an insulating layer 11 and aluminum layers 12 arranged on both sides of the insulating layer 11. The insulating layer 11 is made of PP film, PE film, or PET film.
[0033] In this embodiment, the process flow for preparing the positive electrode sheet is as follows:
[0034] 1. Alkali etching process: The alkaline etching solution is composed of 20-30 g / L Na2CO3, 10-20 g / L NaOH and pure water. The mixed solution is heated to 40-50°C. After the aluminum foil is treated in the solution for 4-5 minutes, it is immediately washed with pure water for 60-90 seconds and dried to obtain an alkaline-etched aluminum film 1 with a relatively rough surface, that is, an unevenly distributed natural aluminum oxide layer 2 is formed on the surface of the aluminum film 1.
[0035] 2. Active material graphene oxide coating process: After drying the alkali-etched aluminum film 1, immediately coat it with a proper amount of ethanol-graphene oxide mixed solution, and wait for the mixed solution to dry naturally or heat and dry.
[0036] The process for preparing the positive electrode sheet provided in this embodiment solves the problems of complex coating process of active materials on the positive electrode current collector aluminum film 1, high cost and short battery life;
[0037] This embodiment only requires two steps to prepare a positive electrode sheet with good conductivity, and the solvent used is water or ethanol solution, which has lower cost than solvents such as NMP or isopropyl alcohol in other inventions.
[0038] This embodiment relies on the physical forces between metallic aluminum and graphene oxide, and between aluminum oxide and graphene oxide to improve the bonding strength between the conductive material and the aluminum film 1, rather than using an adhesive to improve the bonding strength, thereby reducing problems such as battery performance degradation caused by the adhesive.
[0039] The aluminum foil of the present invention is coated with a conductive material after being alkali-etched, which can avoid the problem that the alkali-etching agent is directly mixed into the conductive material, and the produced gas penetrates the aluminum foil. The conductive material on the surface of the alkali-etched aluminum foil of the present invention is evenly distributed, which can effectively inhibit the formation of lithium dendrites during the charging and discharging process of the lithium battery and improve the battery life. Moreover, the conductive material on the surface of the alkali-etched aluminum film is evenly distributed, which can effectively inhibit the formation of lithium dendrites during the charging and discharging process of the lithium battery and improve the battery life.
[0040] In the description of the embodiments of the present utility model, it should be noted that the directions or positional relationships indicated by the terms "upper, lower, inner and outer" are based on the directions or positional relationships shown in the drawings, and are only for the convenience of describing the present utility model and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore cannot be understood as limiting the present utility model. In addition, the terms "first, second or third" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance.
[0041] In the embodiments of the present invention, unless otherwise clearly specified and limited, the terms "install, connect, connect" should be understood in a broad sense, for example: it can be a fixed connection, a detachable connection or an integral connection; it can also be a mechanical connection, an electrical connection or a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.
[0042] Although the present invention has been described with reference to preferred embodiments, various modifications may be made thereto and parts thereof may be replaced with equivalents without departing from the scope of the present invention. In particular, the various technical features mentioned in the various embodiments may be combined in any manner as long as there is no structural conflict. The present invention is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.
Claims
1. A positive electrode sheet, characterized in that: The positive electrode sheet comprises: An aluminum film (1), an aluminum oxide layer (2) with holes arranged on the surface of the aluminum film (1), and a graphene oxide layer (3) arranged on the surface of the aluminum oxide layer (2) away from the aluminum film (1).
2. The positive electrode sheet according to claim 1, characterized in that: The aluminum oxide layer (2) is formed by subjecting the aluminum film (1) to alkaline corrosion treatment with an alkaline etching solution and is discontinuously distributed on the surface of the aluminum film (1).
3. The positive electrode sheet according to claim 1 or 2, characterized in that: The thickness of the aluminum oxide layer (2) is 10 nm to 100 nm.
4. The positive electrode sheet according to claim 3, characterized in that: The thickness of the aluminum film (1) is 3 um to 8 um.
5. The positive electrode sheet according to any one of claims 1, 2 or 4, characterized in that: The thickness of the graphene oxide layer (3) is 10 nm to 2 um.
6. The positive electrode sheet according to any one of claims 1, 2 or 4, characterized in that: The aluminum film (1) is pure aluminum foil or composite aluminum foil.
7. The positive electrode sheet according to claim 6, characterized in that: The composite aluminum foil comprises an insulating layer (11) and aluminum layers (12) arranged on both sides of the insulating layer (11).
8. The positive electrode sheet according to claim 7, characterized in that: The material of the insulating layer (11) is any one of PP film, PE film and PET film.
9. A battery, characterized in that: The battery comprises the positive electrode sheet according to any one of claims 1 to 8.