Polymer and active particle material, battery pole piece, battery and electric equipment
By constructing a single-ion conductor polymer protective layer on the surface of the lithium/silicon anode, the problems of volume change and insufficient SEI protection in the lithium/silicon anode are solved, achieving uniform lithium-ion transport and high-efficiency battery cycle performance.
Patent Information
- Application Number
- CN202410742223.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-06-07
- Publication Date
- 2025-12-09
AI Technical Summary
During cycling, lithium/silicon anodes break due to volume changes and the SEI (Self-Electrically Insulated Electrode) cannot effectively protect them, leading to capacity decay and side reactions, which affect the performance of lithium-ion batteries.
Polymer materials with polyoxanthracene containing single-ion conductors or self-porous polyimide as the main chain backbone are used to construct lithium-ion transport channels through microporous structure and single-ion conductor side chains, thereby improving ionic conductivity and mechanical properties and forming a uniform protective layer.
It achieves uniform lithium-ion transport, reduces concentration polarization, suppresses interfacial side reactions, and improves battery cycle performance and interfacial stability.
Smart Images
Figure CN121086202A_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of polymer materials technology, and in particular to a polymer and active particulate material, battery electrode, battery and electrical device. Background Technology
[0002] Lithium-ion batteries are characterized by high specific energy, long cycle life, high operating voltage, and wide operating temperature range, and are widely used in portable electronic devices, electric vehicles, and other fields. With rapid societal development, the requirements for the energy density of lithium-ion batteries are increasing, while traditional graphite anode materials are gradually approaching their theoretical energy density limit. Therefore, there is an urgent need to develop anode materials with high specific capacity. Lithium metal has a high theoretical specific capacity (3860 mAh / g) and extremely low electrochemical potential (-3.04 V vs. SHE), while silicon also has a high theoretical specific capacity (3579 mAh / g, Li...). 15 Si4) and lower redox potential (0.4V vs. Li / Li + It is a preferred anode material for next-generation high-energy-density batteries.
[0003] However, lithium / silicon anodes face two main problems during cycling: first, the significant volume change leads to anode breakage, causing the active material to lose electrical contact and resulting in rapid capacity decay; second, the solid-electrolyte interface (SEI) cannot effectively protect the anode material, leading to severe side reactions, continuous consumption of electrolyte and active material, and reduced coulombic efficiency and cycling performance, significantly hindering the commercialization of lithium / silicon anodes. Research has found that interface properties are crucial for suppressing side reactions in lithium / silicon anodes. The main reason is that the spontaneously formed original SEI is very fragile and easily broken, repeatedly forming, breaking, and thickening during cycling, consuming large amounts of active lithium and electrolyte. Therefore, designing a continuous, dense, structurally stable, and uniformly ionized artificial SEI layer to replace the original SEI for protecting the lithium / silicon anode is a commonly used modification method.
[0004] Generally, artificial SEI layers can be mainly divided into three categories: organic, inorganic, and organic-inorganic composite protective layers. Organic polymer materials, due to their good processability, can form a continuous and stable protective layer on the surface of active materials, preventing direct contact between the electrolyte and the active material and reducing side reactions, making them the preferred choice for artificial SEI layers. However, organic polymers have poor ion conductivity, which hinders lithium-ion transport, increases interfacial impedance, and affects the performance of both positive and negative electrode materials. Furthermore, traditional organic polymer materials generally achieve lithium-ion transport through chain segment movement, resulting in polymers with ion conductivity typically having poor mechanical properties; it is difficult to simultaneously achieve good ionic conductivity and mechanical properties in polymers. Summary of the Invention
[0005] This application provides a polymer and active particulate material, a battery electrode, and a secondary battery. The polymer material, through its own micropores and single-ion conductor side chains, can achieve high ionic conductivity, promote uniform lithium-ion transport, and effectively solve the problem of poor ion conductivity of organic artificial SEI layers.
[0006] In a first aspect, this application provides a polymer comprising at least one of a polyoxanthracene with a single ion conductor and a self-microporous polyimide with a single ion conductor. The polyoxanthracene with a single ion conductor comprises a polyoxanthracene backbone and a single ion conductor side chain, while the self-microporous polyimide with a single ion conductor comprises a self-microporous polyimide backbone and a single ion conductor side chain. It should be noted that the polyimide provided in this application is a self-microporous polyimide.
[0007] By using polyoxanthracene or microporous polyimide as the main chain backbone of the polymer, a large number of micropores can be constructed, providing channels for cation transport in the battery, such as lithium-ion transport, without hindering electrochemical performance. Simultaneously, polyoxanthracene or microporous polyimide itself possesses excellent mechanical and processing properties, allowing for uniform coating on its surface and adapting to volume changes during battery cycling without cracking. Furthermore, by adding single-ion conductor side chains to the polymer with polyoxanthracene or microporous polyimide as the main chain backbone, the conductivity and transference number of cations (e.g., lithium-ions) can be improved, achieving uniform cation transport and reducing concentration polarization, effectively addressing the problem of poor ion conductivity in organic layers.
[0008] In one possible embodiment of the first aspect of this application, the single-ion conductor side chain includes a carboxylic acid group, a sulfonic acid group, or a sulfonamide group functional group.
[0009] By using carboxylic acid, sulfonic acid, or sulfonamide functional groups as single-ion conductor side chains of polymers, selection can be made from existing materials. These functional groups can improve cation conductivity and lithium-ion transference number, achieve uniform cation transport, and reduce concentration polarization.
[0010] In one possible embodiment of the first aspect of this application, the structure of the polyoxanthracene with a single-ion conductor is as follows.
[0011]
[0012] In the formula, A is the functional group of the polymer backbone with a benzene ring, and R f It is a fluorinated carbon chain with 2-12 carbon atoms, and R is a single-ion conductor functional group.
[0013] In one possible embodiment of the first aspect of this application, the polymer backbone functional group A containing a benzene ring is selected from at least one of the following structures:
[0014]
[0015] In one possible embodiment of the first aspect of this application, the self-porous polyimide structure with a single-ion conductor is as follows:
[0016]
[0017] In the formula, B1 is the functional group of the dianhydride residue backbone after the polymerization of the polymer monomer, B2 is the functional group of the diamine residue polymer backbone after the polymerization of the monomer, and R f It is a fluorinated carbon chain with 2-12 carbon atoms, and R is a single-ion conductor functional group.
[0018] In one possible embodiment of the first aspect of this application, the dianhydride residue backbone functional group B1 after monomer polymerization is selected from at least one of the following structures:
[0019]
[0020] In one possible embodiment of the first aspect of this application, the dianhydride residue backbone functional group B2 after monomer polymerization is selected from at least one of the following structures:
[0021]
[0022] In one possible embodiment of the first aspect of this application, the fluorocarbon chain R f The chemical formula is (CF2). m O(CF2) n , where 0 < m or n ≤ 6, and m / n is an integer.
[0023] In one possible embodiment of the first aspect of this application, the single-ion conductor functional group R is selected from one of the following structures:
[0024]
[0025] In one possible embodiment of the first aspect of this application, X in the single-ion conductor functional group R structure is H, Li, Na or K.
[0026] In one possible embodiment of the first aspect of this application, the specific area of the polymer is ≥80m². 2 / g.
[0027] Secondly, this application provides a positive / negative electrode active particle structure, including a protective layer composed of a polymer as described in any possible embodiment of the first aspect of this application, and a core of positive / negative electrode active particle material.
[0028] Thirdly, this application provides a positive / negative electrode structure, including a protective layer composed of a polymer as described in any possible embodiment of the first aspect of this application, and positive / negative electrode sheets.
[0029] The single-ion conductor microporous polymer material provided in this application serves as a protective layer for the positive / negative electrode active materials and positive / negative electrode sheets in a battery, thereby maintaining good interfacial performance, suppressing interfacial side reactions, and improving the battery's cycle performance during battery cycling.
[0030] Fourthly, this application provides a separator structure, including a coating composed of a polymer as described in any possible embodiment of the first aspect of this application, and a battery separator.
[0031] Fifthly, this application provides a battery comprising a positive electrode, a negative electrode, a separator located between the positive and negative electrodes, and an electrolyte. The positive and negative electrodes comprise the positive and negative electrode active particle structure provided in the second aspect of this application and the positive and negative electrode sheet structure provided in the third aspect of this application, and the separator comprises the separator structure provided in the fifth aspect of this application. The battery provided by this application maintains good interfacial performance and suppresses interfacial side reactions during cycling, exhibiting excellent cycle performance.
[0032] Sixthly, this application provides an electrical device, which includes an electrical component and a power supply component. The power supply component supplies power to the electrical component and includes the battery provided in the fifth aspect of this application. Attached Figure Description
[0033] Figure 1 This is a schematic diagram of the structure of a positive / negative electrode active particle material provided in an embodiment of this application;
[0034] Figure 2a A projection electron microscope image of a negative electrode active particulate material provided in an embodiment of this application;
[0035] Figure 2b Another projection electron microscope image of the negative electrode active particulate material provided in the embodiments of this application;
[0036] Figure 3 A first discharge curve of a button cell provided in an embodiment of this application;
[0037] Figure 4 A cycle performance curve of a coin cell provided in an embodiment of this application;
[0038] Figure 5A schematic diagram of a positive / negative electrode structure provided in an embodiment of this application;
[0039] Figure 6a A schematic diagram of an electron microscope image of a lithium button battery provided in an embodiment of this application;
[0040] Figure 6b A schematic diagram of an electron microscope image of another lithium button battery provided in an embodiment of this application;
[0041] Figure 7a This is a schematic photograph of the lithium deposition morphology of a lithium coin cell provided in an embodiment of this application.
[0042] Figure 7b A schematic photograph of the lithium deposition morphology of another lithium coin cell provided in an embodiment of this application;
[0043] Figure 8 Cycle curve of a lithium button battery provided for an embodiment of this application;
[0044] Figure 9 This is a schematic diagram of a diaphragm structure provided in an embodiment of this application. Detailed Implementation
[0045] To make the objectives, technical solutions, and advantages of this invention clearer and more explicit, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.
[0046] In this application, the term "and / or" describes the relationship between related objects, indicating that three relationships can exist, for example...
[0047] For example, A and / or B can represent: the existence of A alone, the existence of both A and B, or the existence of B alone. A and B can be singular or plural. The character " / " generally indicates that the preceding and following objects have an "OR" relationship.
[0048] In this application, "at least one" means one or more, and "more than one" means two or more. "At least one of the following" or similar expressions refer to any combination of these items, including any combination of single or multiple items. For example, "at least one of a, b, or c", or "at least one of a, b, and c", can both mean: a, b, c, ab (i.e., a and b), ac, bc, or abc, where a, b, and c can be single or multiple.
[0049] It should be understood that in the various embodiments of this application, the order of the above processes does not imply the order of execution. Some or all steps may be executed in parallel or sequentially. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of this application.
[0050] The terminology used in the embodiments of this application is for the purpose of describing particular embodiments only and is not intended to be limiting of this application. The singular forms “a,” “the,” and “the” used in the embodiments of this application and the appended claims are also intended to include the plural forms unless the context clearly indicates otherwise.
[0051] The terms “comprising,” “including,” “containing,” “having,” “comprising,” or other variations thereof are intended to cover non-closed inclusion, and no distinction is made between these terms. The term “comprising” means additional steps and components that may be added without affecting the final result. The term “comprising” also includes the terms “consisting of” and “substantially consisting of”. The compositions and methods / processes of this application comprise, consist of, and substantially consist of the essential elements and limitations described herein, as well as any additional or optional ingredients, components, steps, or limitations described herein.
[0052] All numerical values or expressions relating to component amounts, process conditions, etc., used in the specification and claims are to be understood to be modified with “about” in all cases. All ranges relating to the same component or property include endpoints that can be independently combined. Because these ranges are continuous, they include every value between the minimum and maximum values. It should also be understood that any numerical range referenced in this application is intended to include all subranges within that range.
[0053] The weights of the relevant components mentioned in the embodiments of this application can refer not only to the specific content of each component, but also to the proportional relationship between the weights of the components. Therefore, any scaling up or down of the content of the relevant components according to the embodiments of this application is within the scope disclosed in the embodiments of this application. Specifically, the mass described in the embodiments of this application can be a mass unit known in the chemical industry, such as μg, mg, g, or kg.
[0054] Organic polymer materials, due to their excellent processability, can form a continuous and stable protective layer on the surface of active materials, preventing direct contact between the electrolyte and the active material and reducing side reactions, making them a preferred option for artificial SEI layers. However, organic polymers have poor ion conductivity, which hinders lithium-ion transport, increases interfacial impedance, and affects the performance of both positive and negative electrode materials. Furthermore, traditional organic polymer materials generally achieve lithium-ion transport through chain segment movement, resulting in polymers with ion conductivity typically having poor mechanical properties; it is difficult to simultaneously achieve high ion conductivity and high mechanical properties in polymers. Therefore, this application provides a novel polymer that can combine high ion conductivity and high mechanical properties.
[0055] The polymers provided in this application include self-polymerizing microporous polyimides with single-ion conductors and polyoxanthracenes with single-ion conductors. Polyimides (PI) are a class of polymers containing an imide ring (-CO-NR-CO-) in their main chain, and are organic polymer materials. Polyimides possess repeating imide units and have advantages such as wide operating temperature, chemical resistance, and high strength. Based on the chemical structure of the repeating units, polyimides can be classified into aliphatic, semi-aromatic, and aromatic polyimides. Based on thermal properties, they can be classified into thermoplastic and thermosetting polyimides. Based on whether the polyimide main chain has micropores, they can be classified into polyimides with micropores and polyimides without micropores. The polyimide provided in this application is a self-polymerizing microporous polyimide.
[0056] The polyoxanthracene provided in this application is an aromatic polymer prepared by polyhydroxy alkylation. The oxanthracene unit is formed by the fusion of a pyran ring and two benzene rings, which results in the inclusion of rigid planar tricyclic aromatic heterocycles in the polymer backbone, thus leading to inherent microporosity. It is a novel microporous polymer.
[0057] The single-ion conductor provided in this application is an ion conductor in which only one type of charged ion can be effectively transported under the influence of an electric field, while almost no counterion migration occurs. Single-ion conductors have potential applications in fields such as ion batteries, fuel cells, and solar cells. In these fields, the migration or transport of one type of ion is advantageous, while the migration or transport of ions with opposite charges is disadvantageous. For example, the main function of the electrolyte material in lithium-ion batteries is to transport lithium cations. However, commonly used soluble salt electrolyte materials also contain migratable anions. These anions often exhibit a higher migration rate than cations due to their weaker interaction with the matrix material. The direct result is that a large portion of the conductivity is ineffective conductivity generated by anion migration. Using a single-ion conductor as the electrolyte material can solve this problem.
[0058] Specifically, the polymer provided in this application embodiment comprises at least one of polyoxanthracene with a single ion conductor and a self-microporous polyimide with a single ion conductor. That is, the polymer can be polyoxanthracene with a single ion conductor, a self-microporous polyimide with a single ion conductor, or a combination of both. Typically, polyoxanthracene and self-microporous polyimide form the main chain structure, while the single ion conductor is a side chain structure. The polyoxanthracene with a single ion conductor and the self-microporous polyimide with a single ion conductor will be described in detail below.
[0059] Polyoxane with single-ion conductors comprises a polyoxane backbone and single-ion conductor side chains, as shown in the following formula, illustrating the single-ion conductor...
[0060]
[0061] The polyoxoanthracene structure of the conductor, by introducing single-ion conductor side chains, can improve lithium-ion conductivity and lithium-ion transference number, achieve uniform lithium-ion transport, and reduce concentration polarization, effectively solving the problem of poor ion conductivity of organic layers.
[0062] In one possible implementation, A is a functional group of the polymer backbone with a benzene ring. For example, the functional group A of the polymer backbone with a benzene ring can be selected from the following functional groups:
[0063]
[0064] In one possible implementation, R f It is a fluorocarbon chain, where R is a single-ion conductor functional group. For example, R f It can be a fluorinated carbon chain with 2-12 carbon atoms.
[0065] A polyimide with a single-ion conductor, comprising a polyimide backbone and single-ion conductor side chains, as shown in the following formula, illustrates a self-porous polyimide structure with a single-ion conductor. By introducing single-ion conductor side chains, lithium-ion conductivity and lithium-ion transference number can be improved.
[0066]
[0067] This achieves uniform lithium-ion transport and reduces concentration polarization, effectively solving the problem of poor ion conductivity in organic layers.
[0068] In one possible implementation, B1 is a functional group of the dianhydride residue polymer backbone after monomer polymerization. For example, the functional group B1 of the dianhydride residue polymer backbone after monomer polymerization can be selected from the following functional groups:
[0069]
[0070] In one possible implementation, B2 is a functional group of the main chain of the diamine residue polymer after monomer polymerization. For example, the functional group B2 of the main chain of the diamine residue polymer after monomer polymerization can be selected from the following functional groups:
[0071] In one possible implementation, R f It is a fluorocarbon chain, where R is a single-ion conductor functional group. For example, R f It can be a fluorinated carbon chain with 2-12 carbon atoms.
[0072] This application embodiment achieves high ionic conductivity by introducing single-ion conductor side chains into the polymer, which promotes uniform lithium-ion transport, reduces concentration polarization, and does not hinder the electrochemical performance of the positive and negative electrode materials, effectively solving the problem of poor ion conductivity of organic artificial SEI layers.
[0073] The properties of the polymer with single-ion conductors of this application will be further described below with reference to specific embodiments and comparative examples.
[0074] like Figure 1 The diagram illustrates a positive / negative electrode active particle material structure with a polymer material having a single-ion conductor as a protective layer, as provided in this application. The structure includes a core of positive / negative electrode active particles and a protective layer disposed on the surface of the core. The protective layer is the polymer material provided in this application. In one possible implementation, the core of the positive / negative electrode active particles can be spherical or blocky. This application does not limit the shape of the core. The polymer material provided in this application is coated on the surface of the core. These positive / negative electrode active particles can be used to fabricate the positive / negative electrode sheets of a battery. The battery in this embodiment can be a rechargeable battery, including lithium-ion batteries and sodium-ion batteries.
[0075] In one possible implementation, a single-ion conductor polyoxanthracene is used as a protective layer for the active particulate material, for example, as a protective layer for the negative electrode active particulate material. For example, the negative electrode active particulate material in this embodiment is a silicon-based active particulate material, wherein the silicon-based material includes one or more of elemental silicon, silicon alloys, silicon oxides, and silicon-carbon composite materials, and the silicon-carbon composite material includes a composite of at least one of elemental silicon, silicon alloys, and silicon oxides with a carbon material. The negative electrode active particulate material can also be graphite, hard carbon, soft carbon, or a lithium metal-based material, wherein the lithium metal-based material includes one or more of lithium metal, lithium-containing lithium alloys, and lithium-carbon composite materials, and the lithium-carbon composite material includes a composite of at least one of lithium metal and lithium-containing lithium alloys with a carbon material. The preparation steps of this negative electrode active particulate material structure are as follows:
[0076] S10: Take 10g of single-ion conductor polyoxoanthracene material, structural formula SC-PX-1, and measure the specific surface area of SC-PX-1 using nitrogen adsorption method, which is 380m². 2 / g, its weight-average molecular weight is approximately 104,000;
[0077] S11: Add the SC-PX-1 obtained in step S10 to a beaker, then add 90g of organic solvent N-methyl-2-pyrrolidone (NMP), stir for 4 hours to obtain a polymer solution in which SC-PX-1 is completely dissolved, with a solid content of 10wt%.
[0078] S12: Under mechanical stirring, 490g of silicon-carbon composite material powder is added in small amounts to a beaker containing the above polymer solution, and the powder adhering to the inner wall of the beaker is rinsed with NMP. The overall solid content is adjusted to 25wt%, and the mixture is stirred for 8 hours to obtain a uniformly mixed slurry.
[0079] S13: Place the above slurry in a spray dryer for spray drying and granulation. Set a suitable feeding speed and heating temperature. When the oxygen content and temperature are low, start feeding and spray drying are carried out simultaneously to obtain the dried powder material, i.e., the composite negative electrode active particle material. Its core is a silicon-carbon composite material, and the surface of the core is provided with a polyoxanthracene SC-PX-1 protective layer with a single ion conductor.
[0080] It should be noted that the method for fabricating positive electrode active particles with a polymer protective layer is similar to steps S10-S13, and will not be repeated in this embodiment. Optionally, the positive electrode active particle material includes lithium cobalt oxide (LCO), lithium iron phosphate (LFP), ternary cathode (NCM / NCA), lithium-rich manganese-based cathode (LMO), and sulfur-containing cathode.
[0081] In one possible implementation, a negative electrode sheet is made by preparing a composite negative electrode active particle material through steps S10-S13. The prepared composite negative electrode active particle material is mixed with a conductive agent and a binder in a certain proportion. After thorough mixing, a negative electrode slurry is obtained. The negative electrode slurry is coated on a current collector, dried under vacuum, and then rolled to obtain a negative electrode sheet.
[0082] In one possible implementation, this embodiment provides a method for manufacturing a lithium button battery. A lithium button battery is manufactured using the aforementioned negative electrode sheet. The negative electrode sheet is cut into circular pieces with a diameter of, for example, 13 mm. A lithium metal sheet is used as the counter electrode, Celgard 2400 is used as the separator, and a 1 mol / L LiPF6 ethylene carbonate (EC) and diethyl carbonate (EMC) (v / v = 1:1) mixed solution is used as the electrolyte solution. The battery is assembled into a CR2032 type button battery in an argon-filled glove box.
[0083] like Figure 2a The image shown is a projection electron microscope image of the negative electrode active particle material with a polymer as a protective layer and a single-ion conductor. It can be seen that there is a clear protective layer on the surface of the composite negative electrode active material.
[0084] like Figure 2b The image shown is a projection electron microscope image of a negative electrode active particulate material with a polymer without single-ion conductors as a protective layer.
[0085] As can be seen from the comparison of the two figures, the polymer with single-ion conductors can be used as a protective layer to achieve uniform and dense coating of silicon-carbon composite materials, thereby hindering the direct contact between the electrolyte and the active material and suppressing side reactions.
[0086] like Figure 3 Figure a shows the first discharge curve of a coin cell battery made of negative electrode active particles with a polymer protective layer containing a single-ion conductor; Figure b shows the first discharge curve of another coin cell battery made of negative electrode active particles without a polymer protective layer containing a single-ion conductor. Comparing the two curves shows that the initial charge capacity and initial coulombic efficiency of the negative electrode active particles with the polymer protective layer containing a single-ion conductor are consistent with those of the negative electrode active particles without a single-ion conductor. This indicates that the polymer with a single-ion conductor does not hinder the performance of the active material, demonstrating that the polymer material with a single-ion conductor has excellent lithium-ion conductivity.
[0087] like Figure 4As shown, curve a is a cycle performance curve of a coin cell made of negative electrode active particles without a polymer with a single-ion conductor as a protective layer; curve b is a cycle performance curve of another type of coin cell made of negative electrode active particles with a polymer with a single-ion conductor as a protective layer. Comparing the two curves, it can be seen that after 160 cycles, the coin cell made with the polymer with a single-ion conductor retains 88.06% of its capacity, while the coin cell made without the polymer with a single-ion conductor retains only 79.57%. This indicates that the silicon-carbon composite material protected by the polymer with a single-ion conductor maintains better interfacial performance and particle morphology during cycling, thus demonstrating that the single-ion conductor microporous polymer material can significantly improve the cycle performance of silicon-carbon composite materials.
[0088] Figure 5 This is a schematic diagram of a positive / negative electrode sheet with a microporous polymer having a single-ion conductor as a protective layer, as provided in this application.
[0089] The structure consists of a protective layer disposed on the surface of the positive / negative electrode plates of the battery, and the positive / negative electrode plates themselves. The protective layer is made of a polymer material with single-ion conductors. The battery in this embodiment can be a rechargeable battery, including lithium-ion batteries and sodium-ion batteries.
[0090] In one possible implementation, embodiments of this application provide a method for preparing positive / negative electrode protective layers using a self-porous polyimide with a single-ion conductor. The self-porous polyimide with a single-ion conductor has micropores, and the preparation steps are as follows:
[0091] S20: Take 10g of a single-ion conductor, self-porous polyimide material, structurally denoted as SC-PI-1. The specific surface area of SC-PI-1, measured by nitrogen adsorption, is 350m². 2 / g, its weight-average molecular weight is approximately 153,000;
[0092] S21: Add the above SC-PI-1 to a beaker, then add 90g of organic solvent NMP, stir for 4 hours to obtain a polymer solution in which SC-PI-1 is completely dissolved, with a solid content of 10wt%.
[0093] S22: The polymer solution obtained in step S21 is uniformly coated onto the surface of the lithium metal negative electrode sheet by means of scraping, spin coating or spraying, and heated at 60°C for 8 hours in a vacuum oven to obtain the dried negative electrode sheet, i.e., the composite negative electrode sheet, which is a lithium metal negative electrode. The surface of the electrode sheet is provided with a polyimide SC-PI-1 protective layer of single ion conductor.
[0094] In one possible implementation, this embodiment provides a method for manufacturing a lithium button cell battery. The composite negative electrode sheet obtained in steps S20-S22 is cut into circular sheets with a diameter of 13 mm. The materials used for the negative electrode sheet include graphite electrode sheets, hard carbon electrode sheets, soft carbon electrode sheets, silicon-based material electrode sheets, and lithium metal-based material electrode sheets. The silicon-based material used includes one or more of elemental silicon, silicon alloys, silicon oxides, and silicon-carbon composite materials. The silicon-carbon composite material includes a composite formed by at least one of elemental silicon, silicon alloys, and silicon oxides with a carbon material. Furthermore, the lithium metal-based material used includes one or more of lithium metal, lithium-containing lithium alloys, and lithium-carbon composite materials. The lithium-carbon composite material includes a composite formed by at least one of lithium metal and lithium-containing lithium alloys with a carbon material.
[0095] Using lithium cobalt oxide (LCO) electrodes as the counter electrode, the positive electrode materials include lithium cobalt oxide (LCO) electrodes, lithium iron phosphate (LFP) electrodes, ternary positive electrode NCM / NCA electrodes, lithium-rich manganese-based LMO electrodes, and sulfur-containing positive electrode electrodes; Celgard 2400 is used as the separator, and a 1 mol / L LiPF6 ethylene carbonate (EC) and diethyl carbonate (EMC) (v / v = 1:1) mixed solution is used as the electrolyte solution. The CR2032 coin cell is assembled in an argon-filled glove box.
[0096] like Figure 6a The image shown is an electron microscope image of a lithium button cell made using an unprotected lithium metal anode. The microscope image shows that the surface of the lithium metal anode is uneven and the microstructure is irregular.
[0097] like Figure 6b The image shown is a schematic electron microscope image of a lithium coin cell made with a lithium metal anode with a polyimide protective layer containing a single-ion conductor. It can be seen that the surface of the anode sheet is uniform and smooth, without obvious unevenness.
[0098] Therefore, it can be seen that the microporous polyimide protective layer with single-ion conductor can form a uniform and dense protective layer on the surface of lithium metal anode sheet, improve the uniformity of the electrode surface, and at the same time hinder the direct contact between the electrolyte and the active material, thus avoiding side reactions.
[0099] like Figure 7a The image shown is a photograph of the lithium deposition morphology of a lithium coin cell made using an unprotected lithium metal anode. It can be seen that the lithium metal anode exhibits obvious lithium dendrite morphology after lithium deposition, which is detrimental to the cycle performance of the lithium metal anode.
[0100] like Figure 7bThe image shown is a photograph of the lithium deposition morphology of a lithium coin cell made using a lithium metal anode with a microporous polyimide protective layer and a single-ion conductor. It can be seen that the composite anode sheet maintains a uniform and dense lithium deposition morphology without obvious dendrite formation.
[0101] Therefore, it can be seen that the microporous polyimide protective layer with single-ion conductor can form a uniform and dense protective layer on the surface of lithium metal anode sheet, which can effectively promote the uniform transport of lithium ions, inhibit the growth of lithium dendrites, and further avoid side reactions.
[0102] like Figure 8 The curve shown in Figure a is the cycling curve of a lithium coin cell made with an unprotected lithium metal anode. When the capacity retention of the coin cell decays to 80%, the number of cycles is only 81.
[0103] like Figure 8 The curve shown in Figure b is a cycle curve of a lithium coin cell made using a lithium metal anode with a polyimide protective layer containing a single-ion conductor. When the capacity retention of the coin cell decays to 80%, the composite anode electrode has 130 cycles.
[0104] Therefore, it can be seen that lithium metal anodes with single-ion conductor polymer materials can effectively protect lithium metal anodes, reduce the loss of active lithium and the generation of dead lithium, and improve the cycle performance of lithium metal anodes.
[0105] Figure 9 This is a schematic diagram of a membrane structure with a single-ion conductor polymer material as a coating, as provided in this application.
[0106] The structure consists of a battery separator and a coating disposed on at least one surface of the battery separator. The coating is made of a polymer material with single-ion conductors. The battery in this embodiment can be a rechargeable battery, including lithium-ion batteries and sodium-ion batteries.
[0107] In one possible implementation, embodiments of this application provide a method for preparing a battery separator coating using polyoxanthracene with a single-ion conductor. For example, the battery separator uses polypropylene (PP) and polyethylene (PE) as examples, and the specific preparation steps are as follows:
[0108] S30: Take 10g of single-ion conductor polyoxanthracene material, with the structural formula SC-PX-2. The specific surface area of SC-PX-2 was measured to be 400m2 / g by nitrogen adsorption method, and its weight-average molecular weight was approximately 206,000.
[0109] S31: Add the SC-PX-2 obtained in step S30 to a beaker, then add 90g of organic solvent NMP, stir for 4 hours to obtain a polymer solution in which SC-PX-2 is completely dissolved, with a solid content of 10wt%.
[0110] S32: The polymer solution obtained in step S31 is uniformly coated onto any one or two surfaces of the PP / PE separator by means of scraping / spinning / spraying, etc., and heated in a vacuum oven at 60°C for 8 hours to obtain the dried separator, i.e., the composite separator. Any one or two surfaces of the separator are provided with a single-ion conductor polyoxoanthracene SC-PX-2 protective layer.
[0111] In one possible implementation, this application provides a method for preparing a lithium button battery, the specific steps of which are: the composite separator obtained in steps S30-S32 is combined with positive and negative electrode sheets, and a mixed solution of ethylene carbonate (EC) and diethyl carbonate (EMC) (v / v = 1:1) of 1 mol / L LiPF6 is used as the electrolyte solution to assemble a CR2032 type button battery in an argon-filled glove box.
[0112] For the same technical purpose, embodiments of this application also provide a battery, including at least one of the positive / negative electrode active particle structure, positive / negative electrode sheet structure, and separator structure provided in embodiments of this application. This battery can be a secondary battery, such as a lithium-ion battery, or a lithium button battery, or a sodium-ion battery. This application does not limit the type or form of the battery.
[0113] This application also provides an electrical device, which includes an electrical component and a power supply component. The power supply component supplies power to the electrical component and includes the battery provided in this application embodiment. The electrical device includes electronic devices, such as mobile terminals: mobile phones, cameras, watches, and tablet computers, as well as electric vehicles, electric cars, electric motorcycles, electric bicycles, and electric tricycles, and energy storage devices, etc.
[0114] The above are merely specific embodiments of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.
Claims
1. A polymer, characterized in that, The polymer includes at least one of polyoxanthracene with a single ion conductor and a self-microporous polyimide with a single ion conductor; the polyoxanthracene with a single ion conductor includes a polyoxanthracene main chain and a single ion conductor side chain, and the self-microporous polyimide with a single ion conductor includes a polyimide main chain and the single ion conductor side chain.
2. The polymer according to claim 1, characterized in that, The single-ion conductor side chain includes a carboxylic acid group, a sulfonic acid group, or a sulfonamide group.
3. The polymer according to claim 1 or 2, characterized in that, The structure of the polyoxanthracene with a single ion conductor is as follows. In Formula 1, A is a functional group in the polymer backbone containing a benzene ring, and R... f It is a fluorinated carbon chain with 2-12 carbon atoms, and R is a single-ion conductor functional group.
4. The polymer according to claim 3, characterized in that, The benzene ring-containing polymer backbone functional group A is selected from at least one of the following structures:
5. The polymer according to claim 1, characterized in that, The self-porous polyimide structure with a single-ion conductor is as follows: In the formula, B1 is the functional group of the dianhydride residue backbone after monomer polymerization, B2 is the functional group of the diamine residue polymer backbone after monomer polymerization, and R f It is a fluorinated carbon chain with 2-12 carbon atoms, and R is a single-ion conductor functional group.
6. The polymer according to claim 5, characterized in that, The functional group B1 of the dianhydride residue backbone after monomer polymerization is selected from at least one of the following structures:
7. The polymer according to claim 5, characterized in that, The B2 functional group of the diamine residue polymer backbone after monomer polymerization is selected from at least one of the following structures.
8. The polymer according to any one of claims 3-7, characterized in that, The R f The chemical formula is (CF2). m O(CF2) n , where 0 < m or n ≤ 6, and m / n is an integer.
9. The polymer according to any one of claims 3-7, characterized in that, R is selected from one of the following structures:
10. The polymer according to claim 9, characterized in that, X is H, Li, Na, or K.
11. The polymer according to any one of claims 1-10, characterized in that, The specific area of the polymer is ≥80m². 2 / g.
12. A positive / negative electrode active particle structure, characterized in that, It includes a protective layer composed of a polymer as described in any one of claims 1-11 and a core of positive / negative electrode active particulate material.
13. A positive / negative electrode structure, characterized in that, It includes a protective layer composed of a polymer as described in any one of claims 1-11, and positive / negative electrode sheets.
14. A diaphragm structure, characterized in that, It includes a coating composed of a polymer as described in any one of claims 1-11, and a battery separator.
15. A battery, characterized in that, Includes the structure as described in any one of claims 12-14.
16. An electrical appliance, characterized in that, It includes a power-consuming component and a power supply component, wherein the power supply component supplies power to the power-consuming component, and the power supply component includes the battery as described in claim 15.