Optimized undercoat functional current collector and preparation method thereof, pole piece and battery

Abstract

The application discloses a kind of function fluid of optimizing primer layer and its preparation method, pole piece and battery, including high polymer base film layer, recrystallization primer layer outside high polymer base film layer and metal layer outside recrystallization primer layer;The composition of recrystallization primer layer is the recrystallization product of metal oxide.This application repairs lattice defect by recrystallization, forms dense and continuous crystal net, and can optimize metal deposition behavior by recrystallization primer layer, and its dense crystal structure forms physical barrier layer, can effectively inhibit electrolyte penetration, and block corrosive ions and erode base film, and by constructing recrystallization primer layer, optimize electronic transmission path, avoid local current concentration.This application improves the comprehensive performance of current collector by the dual action of interface stability and process adaptability.

Description

Technical Field

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

[0002] Current collectors, as the core carriers of electron transport in the positive and negative electrode materials of lithium-ion batteries, are an important component of the battery structure. Composite current collectors employing a "metal-polymer-metal" sandwich structure have shown significant potential in improving battery safety and energy density due to their unique structural advantages. Current fabrication processes for composite aluminum current collectors are mainly based on polymer thin film substrates, using techniques such as vacuum evaporation or magnetron sputtering to deposit nanoscale metal oxide layers and metal coatings.

[0003] The performance advantages of composite current collector materials have been experimentally verified, but several technical bottlenecks remain due to limitations in equipment precision and process maturity. Specifically, metal oxide layers formed by vacuum evaporation and magnetron sputtering often exhibit insufficient crystallinity and microstructural defects, leading to complex surface morphology. This structural characteristic weakens the interfacial bonding strength between the metal layer and the polymer base film, while also reducing the adhesion between different coatings. In the battery operating environment, such bonding defects significantly reduce the material's resistance to electrolyte corrosion, causing interfacial delamination between the metal coating and the base film. Metal delamination not only directly damages the conductive network of the current collector, leading to a significant decrease in the conductivity of the electrode material, but also exacerbates the increase in battery internal resistance, ultimately creating safety hazards. Summary of the Invention

[0004] The purpose of this invention is to provide an optimized functional current collector for the substrate, its preparation method, electrode, and battery, thereby solving the above-mentioned problems by improving the performance of the functional current collector.

[0005] To achieve the above objectives, the technical solution provided by the present invention is as follows:

[0006] The first aspect of this application provides an optimized underlayer functional current collector, including a polymer base film layer, a recrystallized underlayer outside the polymer base film layer, and a metal layer outside the recrystallized underlayer.

[0007] The recrystallized underlayer is composed of recrystallized products of metal oxides.

[0008] The second aspect of this application provides a method for preparing an optimized functional current collector for the substrate, comprising the following steps:

[0009] S1: Prepare a metal oxide layer on the surface of a polymer-based film;

[0010] S2: The metal oxide layer is recrystallized using an oxidizing agent to form a recrystallized underlayer on the surface of the polymer base film layer;

[0011] S3: Prepare a metal layer on the surface of the recrystallized base layer.

[0012] To optimize the above technical solution, the specific measures also include:

[0013] Furthermore, the metal oxide layer is prepared by physical vapor deposition, chemical vapor deposition, or in-situ molding.

[0014] Furthermore, the thickness of the metal oxide layer is 2–20 nm.

[0015] Furthermore, the oxidant is selected from at least one of sodium periodate, potassium periodate, potassium permanganate, potassium dichromate, potassium chlorate, hydrogen peroxide, trivalent cobalt salt, and oxyacid salt.

[0016] Preferably, the recrystallization reaction using an oxidant specifically comprises:

[0017] The metal oxide layer is oxidized using a solution of oxidizing agent, and then baked at 80-120°C to form a recrystallized base layer.

[0018] Furthermore, the oxidation of the metal oxide layer using an oxidizing agent solution can be carried out by any one of coating, spraying, electrophoresis, or dip coating.

[0019] Furthermore, the metal oxide underlayer is selected from any one of nickel oxide, aluminum oxide, and silicon oxide.

[0020] A third aspect of this application provides an electrode comprising the aforementioned functional current collector.

[0021] A fourth aspect of this application provides a battery comprising the aforementioned electrode.

[0022] Compared with the prior art, the beneficial effects of the present invention are:

[0023] This invention involves recrystallizing the metal oxide layer of a functional current collector to form a recrystallized underlayer between the polymer base film and the metal layer. This recrystallized underlayer improves the bonding force between the metal layer and the polymer base film, as well as between the metal layers themselves. This reduces problems such as discontinuity and localized detachment of the metal layer caused by poor bonding between the metal layer and the polymer base film, thereby enhancing the electrolyte corrosion resistance of the functional current collector.

[0024] This invention repairs lattice defects through recrystallization, forming a dense and continuous crystal network, thereby strengthening the chemical bonding of the organic-inorganic interface. The recrystallized underlayer of this invention can optimize metal deposition behavior, and its dense crystal structure forms a physical barrier layer that can effectively inhibit electrolyte penetration and block the erosion of the base film by corrosive ions. The recrystallized underlayer of this invention also significantly optimizes the electron transport path by eliminating amorphous interface phases, avoiding local current concentration.

[0025] Thus, the synergistic effect of the structure and function of the present invention achieves a systematic improvement in the mechanical strength, interface stability and corrosion resistance of the current collector. Attached Figure Description

[0026] Figure 1 : A schematic diagram of the optimized bottom layer functional current collector of the present invention.

[0027] In the diagram: 1-Polymer base film layer, 2-Recrystallized base layer, 3-Metal layer. Detailed Implementation

[0028] The present invention will be further described in detail below through specific embodiments, but it should not be construed as limiting the scope of the subject matter of the present invention to the following embodiments. All technologies implemented based on the above content of the present invention fall within the scope of the present invention.

[0029] Unless otherwise specified, the experimental methods used in the following examples are conventional methods, and the reagents, methods and equipment used are conventional reagents, methods and equipment in this technical field.

[0030] For the sake of brevity, this article only discloses some numerical values ​​and the range of options. However, any lower limit can be combined with any upper limit to form an unspecified range; and any lower limit can be combined with other lower limits to form an unspecified range. Similarly, any upper limit can be combined with any other upper limit to form an unspecified range; the options in the range of options can also be combined arbitrarily.

[0031] Unless otherwise stated, the terms used in this application have their common meanings as commonly understood by those skilled in the art. Unless otherwise stated, the numerical values ​​of the parameters mentioned in this application can be measured using various measurement methods commonly used in the art.

[0032] This invention provides an optimized bottom-layer functional collector, such as... Figure 1 As shown, it includes a polymer base film layer 1, a recrystallized underlayer 2 on the outside of the polymer base film layer, and a metal layer 3 on the outside of the recrystallized underlayer.

[0033] The composition of the recrystallized base layer 2 is a recrystallized product of metal oxides.

[0034] This invention also provides a method for preparing an optimized functional current collector for the underlayer, comprising the following steps:

[0035] S1: Prepare a metal oxide layer on the surface of a polymer-based film;

[0036] S2: The metal oxide layer is recrystallized using an oxidizing agent to form a recrystallized underlayer on the surface of the polymer base film layer;

[0037] S3: Prepare a metal layer on the surface of the recrystallized base layer.

[0038] This invention enhances the conductivity of the material through recrystallization with an oxidizing agent and significantly improves the interfacial bonding strength between the substrate and the underlayer by forming stable chemical bonds with oxygen-containing functional groups in the polymer base film. Furthermore, the optimized underlayer structure strengthens the anchoring ability of subsequent metal layer ions at the interface, thereby progressively increasing the interlayer adhesion and ultimately achieving a systematic enhancement of overall interfacial stability.

[0039] This technology effectively solves defects such as incomplete deposition and pinholes in metal layer preparation processes, such as vacuum evaporation, while significantly suppressing metal layer detachment, cracking, and discontinuity in functional current collectors in electrolyte environments. Through the dual improvement in interface stability and process adaptability, this solution enables the current collector to meet the stringent requirements for high-reliability materials in the new energy field.

[0040] This invention constructs a functional recrystallization transition layer between a polymer base film and a metal layer through an oxidant-induced recrystallization process, achieving multi-scale interface control and structural optimization.

[0041] During recrystallization, the oxidant first acts as a lattice activator in the phase transition of the metal oxide layer. By releasing active oxygen species, it promotes the dissociation and recombination of aluminum-oxygen bonds, driving the transformation of amorphous or low-crystallinity oxides into a highly ordered crystal structure. This reconstruction process effectively repairs lattice defects, forming a dense and continuous crystal network. The grain orientation of this network forms a topological match with the surface morphology of the polymer base film, enhancing the interface anchoring ability through mechanical interlocking. Simultaneously, the reconstructed crystal surface exposes a large number of unsaturated oxygen atoms and metal active sites, which chemically adsorb onto the polar functional groups of the polymer base film. Through oxidant-induced hydroxylation reactions, a stable hydrogen bond network is formed, achieving chemical bonding strengthening of the organic-inorganic interface.

[0042] The structural characteristics of the recrystallized underlayer further optimize the metal deposition behavior. Its regularly arranged crystal faces provide an epitaxial growth template for metal atoms, significantly reducing the lattice mismatch stress at the heterogeneous interface. Metal atoms form strong covalent bonds with oxygen vacancies in the oxide lattice, fundamentally solving the problem of insufficient adhesion caused by physical adhesion in traditional coatings. This strengthened interface effectively inhibits electrolyte penetration, and its dense crystal structure forms a physical barrier layer, blocking corrosive ions from eroding the base film. Simultaneously, the high crystallinity surface reduces the density of electrochemically active sites, inhibiting the oxidation and dissolution of the metal layer through a passivation effect. Under dynamic operating conditions, the gradient-designed difference in the coefficient of thermal expansion endows this transition layer with stress buffering capabilities, absorbing the volumetric deformation energy during electrode cycling and preventing the propagation of metal layer cracks caused by interfacial fatigue.

[0043] From the perspective of electrochemical performance, the recrystallized layer also significantly optimizes the electron transport path by eliminating the amorphous interface phase. Its three-dimensional interconnected crystal structure reduces the Schottky barrier at the contact interface and promotes carrier tunneling. The anisotropic conductivity guides the metal layer to form a uniform deposition morphology, avoiding dendrite growth caused by local current concentration.

[0044] This synergistic effect of structure and function ultimately achieves a systematic improvement in the mechanical strength, interface stability, and corrosion resistance of the current collector, providing a solution for the long-term cycle reliability of high-energy-density batteries.

[0045] In some preferred embodiments, the metal oxide layer is prepared by physical vapor deposition or chemical vapor deposition.

[0046] Specifically, physical vapor deposition is preferably vacuum evaporation or magnetron sputtering; chemical vapor deposition is preferably atmospheric pressure chemical vapor deposition or plasma-enhanced chemical vapor deposition; other optional methods can also be used in this invention, such as in-situ forming of a metal oxide passivation layer on the surface of the metal layer.

[0047] The metal layer in this invention can preferably be prepared by commonly used methods such as vacuum evaporation or magnetron sputtering.

[0048] The polymer base film layer in this invention can be selected from at least one of PET (polyethylene terephthalate), PE (polyethylene), PP (polypropylene), PEN (polyethylene naphthalate), PPTA (para-aromatic polyamide), PI (polyimide), PC (polycarbonate), PEEK (polyether ether ketone), POM (polyoxymethylene), PPS (polyphenylene sulfide), PPO (polyphenylene oxide), PVC (polyvinyl chloride), PA (polyamide) or PTFE (polytetrafluoroethylene), preferably PET (polyethylene terephthalate).

[0049] In some embodiments, the thickness of the metal oxide layer is 2 to 20 nm, preferably 3 to 15 nm.

[0050] The thickness of the polymer base film and the metal layer can be limited by the thickness of conventional functional current collectors, such as 2-10 μm for the polymer base film and 1-8 μm for the metal layer.

[0051] In some embodiments, the oxidant is, non-limitingly, selected from at least one of sodium periodate, potassium periodate, potassium permanganate, potassium dichromate, potassium chlorate, hydrogen peroxide, trivalent cobalt salts, and oxoacid salts.

[0052] In some embodiments, the reaction for recrystallization using an oxidizing agent is specifically as follows:

[0053] The metal oxide layer is oxidized using a solution of oxidizing agent, and then baked at 80-120°C to form a recrystallized base layer.

[0054] The oxidation of the metal oxide layer is carried out using an oxidizing agent solution, and the method adopted is any one of coating, spraying, electrophoresis or spray coating.

[0055] The oxidant solution of the present invention is a high-concentration solution, and those skilled in the art can select and formulate it according to the different strengths and solubilities of each oxidant.

[0056] In some embodiments, the metal oxide underlayer is selected from any one of nickel oxide, aluminum oxide, and silicon oxide.

[0057] The functional current collector in this invention is preferably an aluminum functional current collector.

[0058] The present invention also provides an electrode comprising the above-described functional current collector.

[0059] The present invention also provides a battery comprising the above-described electrode.

[0060] The technical solution of the present invention will be further described in detail below with reference to specific embodiments:

[0061] Example 1

[0062] The specific steps for preparing a high-performance aluminum functional current collector are as follows:

[0063] (1) A 7 nm thick nickel oxide layer was prepared on a 6 μm thick PET substrate film by magnetron sputtering to obtain the first intermediate material; the parameters of the magnetron sputtering were argon flow rate: 800 sccm and power: 15 kW.

[0064] (2) The first intermediate material is treated by solution coating with a sodium periodate solution of 2.0 mol / L at a winding speed of 200 m / min and a solution flow rate of 1 L / min. The coated film roll is then heated and baked at 100°C to obtain the second intermediate material.

[0065] (3) A 2μm thick aluminum layer is prepared on the surface of the second intermediate material obtained in step (2) by vacuum evaporation to obtain an aluminum functional current collector, wherein the wire feed rate is 350mm / min and the winding speed is 13m / min.

[0066] Example 2

[0067] The scheme in this embodiment is basically the same as that in embodiment 1, except that: in step (1), a 7nm thick aluminum oxide is prepared by magnetron sputtering.

[0068] Example 3

[0069] The scheme in this embodiment is basically the same as that in embodiment 1, except that: in step (1), a 7nm thick aluminum oxide is prepared by vacuum evaporation.

[0070] Example 4

[0071] The scheme in this embodiment is basically the same as that in embodiment 1, except that step (2) uses a 0.015 mol / L potassium periodate solution.

[0072] Comparative Example 1

[0073] The difference between this comparative example and Example 1 is that the aluminum functional current collector is not prepared by the bottom layer recrystallization process, i.e., it does not include step (2), while everything else is the same as Example 1.

[0074] Comparative Example 2

[0075] The difference between this comparative example and Example 3 is that the aluminum functional current collector is not prepared by the bottom layer recrystallization treatment, i.e., it does not include step (2), while everything else is the same as Example 3.

[0076] This application conducted multiple experiments under the conditions of the above embodiments and comparative examples, and the average value of the test results under each condition of the embodiments and comparative examples was taken. The results are shown in Table 1.

[0077] Test method:

[0078] 1. Electrolyte immersion test: Cut 6*8cm samples, seal them with aluminum-plastic film, inject 10ml of lithium iron phosphate / ternary electrolyte into each bag of samples in a glove box, seal the samples with a sealing machine and place them in the glove box for 3 days; after 3 days, take out the samples, immerse them in ethanol in a fume hood to clean off the surface electrolyte, and then perform a coating peel strength test on the samples.

[0079] 2. Coating peel force is measured using an electronic peel force tester (model BLD-200H): Cut a 120×50mm sample, attach the sample to a steel plate with 3M double-sided adhesive, roll it, then attach 3M transparent adhesive to the sample, roll it again, and place the sample on the fixture of the electronic peel force tester to test the sample adhesion force value.

[0080] 3. The number of pinholes is measured by a defect detector: Cut a 1×1m sample, place the sample on the detection surface of the defect detector, ensure that the surrounding area is opaque, turn off the indoor lights, observe from a height distance of about 0.5 meters, and count the visible pinholes on the sample;

[0081] Table 1. Measurement results of each embodiment and comparative example.

[0082]

[0083] The comparison of Examples 1 to 4 shows that the underlayers prepared by different process methods can all be effectively optimized by recrystallization with oxidants. Different oxidants can achieve similar results, and this solution can be achieved for both nickel oxide and aluminum oxide underlayers.

[0084] By comparing Example 1 and Comparative Examples 1 and 2, it can be seen that compared with the ordinary oxide undercoat without oxidation recrystallization in the prior art, the solution of this application can significantly improve the peel strength of the coating and the peel strength of the coating after immersion in electrolyte, and greatly reduce the number of pinholes, almost achieving pinhole-free, thus significantly improving the overall performance of the current collector.

[0085] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Any simple modifications, equivalent substitutions, and improvements made by those skilled in the art to the above embodiments without departing from the scope of the technical solution of the present invention, based on the technical essence of the present invention, shall still fall within the protection scope of the technical solution of the present invention.

Claims

1. A functional collector for optimizing the underlying layer, characterized in that, It includes a polymer base film layer, a recrystallized underlayer outside the polymer base film layer, and a metal layer outside the recrystallized underlayer. The recrystallized underlayer is composed of recrystallized products of metal oxides; The formation of the recrystallized underlayer is as follows: the metal oxide layer is oxidized using a solution of an oxidizing agent, and then baked at 80~120℃ to form the recrystallized underlayer.

2. A method for preparing an optimized functional current collector for layering, characterized in that, Includes the following steps: S1: Prepare a metal oxide layer on the surface of a polymer-based film; S2: The metal oxide layer is recrystallized using an oxidizing agent to form a recrystallized underlayer on the surface of the polymer base film layer; S3: Prepare a metal layer on the surface of the recrystallized underlayer; The specific reaction involving recrystallization using an oxidizing agent is as follows: The metal oxide layer is oxidized using a solution of oxidizing agent, and then baked at 80~120℃ to form a recrystallized base layer.

3. The method for preparing the optimized underlayer functional current collector according to claim 2, characterized in that: The metal oxide layer is prepared by physical vapor deposition, chemical vapor deposition or in-situ molding.

4. The method for preparing the optimized underlay functional current collector according to claim 2, characterized in that: The thickness of the metal oxide layer is 2~20nm.

5. The method for preparing the optimized underlayer functional current collector according to claim 2, characterized in that: The oxidant is selected from at least one of sodium periodate, potassium periodate, potassium permanganate, potassium dichromate, potassium chlorate, and hydrogen peroxide.

6. The method for preparing the optimized underlayer functional current collector according to claim 2, characterized in that: The oxidation of the metal oxide layer using an oxidizing agent solution can be carried out by any one of coating, spraying, electrophoresis, or spraying.

7. The method for preparing the optimized underlayer functional current collector according to claim 2, characterized in that: The metal oxide underlayer is selected from any one of nickel oxide, aluminum oxide, and silicon oxide.

8. An electrode sheet, characterized in that: The optimized layer-forming functional current collector is prepared by the method described in claim 1 or any one of claims 2 to 7.

9. A battery, characterized in that: It includes the electrode sheet as described in claim 8.

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