Functional current collector with high-binding-force priming layer

Abstract

The invention discloses a functional current collector with a high-binding-force bottoming layer, and relates to the technical field of battery materials. According to the invention, different nickel-containing hydroxides, namely alpha-Ni (OH) 2 powder, beta-Ni (OH) 2 powder and gamma-NiOOH powder, are introduced into a high-temperature hot-melt polymer to generate NiO with different crystal structures; alpha-Ni (OH) 2, gamma-NiOOH and beta-Ni (OH) 2 are different nickel-containing hydroxides generated from nickel salt at a low temperature, and different nickel-containing hydroxides can be dehydrated at a high temperature to generate alpha-NiO, gamma-NiO and beta-NiO with different crystal forms and NiO with different crystal structures, so that the crystal state generated by the base membrane is promoted, and the base membrane chemically reacts with surface functional groups to form coordinate bonds in the production process of the base membrane; and the adhesive force between the coating and a metal layer, the coating binding force and the electrolyte corrosion resistance are effectively improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of battery materials, and particularly relates to a functional current collector with a high-bonding-force base layer. BACKGROUND

[0002] The current collector is a structure or component for collecting current in a lithium ion battery, and the current collector collects the current generated by the active material of the battery to form a larger current output, thereby realizing the process of converting chemical energy into electrical energy. In the field of lithium ion batteries, the current collector is an important component of the lithium ion battery. Compared with a single current collector, the functional current collector has a significant advantage due to its "sandwich structure", which can improve the safety of the battery by virtue of the "short circuit effect", and can also improve the energy density by reducing the surface density, thereby improving the comprehensive performance of the lithium ion battery in terms of safety, high specific energy and long service life.

[0003] However, the functional current collector has excellent performance compared with the traditional current collector, but still has certain technical difficulties: firstly, the base layer in the prior art is mainly attached to the surface of the base film by evaporation, and only ordinary mechanical bonding is formed between the two, which leads to insufficient bonding force between the base layer and the base film, weak interlayer bonding force, metal layer delamination, and a significant decrease in the cycle life of the battery cell, and even performance "dive" phenomenon; secondly, there is a lack of effective crystallization promotion technical scheme in the preparation process of the current functional current collector, which leads to insufficient crystallinity of the base film, affects the physical stability of the base film itself, and further limits the interfacial bonding strength between the base layer and the base film, and it is difficult to meet the long-term stability requirement of the high-reliability battery on the current collector.

[0004] In view of the above problems, it is of great practical significance to prepare a functional current collector with a high-bonding-force base layer. SUMMARY

[0005] The present application aims to provide a functional current collector with a high-bonding-force base layer to solve the problems raised in the background.

[0006] In order to solve the above technical problems, the present application provides the following technical scheme: A functional current collector with a high-bonding-force base layer, the functional current collector comprising a base film and a base layer, the base film containing different crystal structures of nickel oxide, and the different crystal structures of nickel oxide comprising one or more of alpha-NiO, beta-NiO and gamma-NiO.

[0007] More preferably, the thickness of the base film is 2-6 mu m, and the thickness of the base layer is 0.1-2 mu m.

[0008] More preferably, the different crystal forms of nickel oxide are composed of two of alpha-NiO, beta-NiO and gamma-NiO, and the mass ratio of the two is 1:1.

[0009] More preferably, the preparation of the functional current collector fluid comprises the following steps: Step 1: dry the base film raw material, high-temperature hot melt to obtain a hot melt polymer; add different nickel-containing hydroxide powders once, stir and melt to heat to obtain a mixed polymer; transfer it to a mold, add different nickel-containing hydroxide powders again, cover the surface of the mixed polymer; heat, longitudinally stretch, transversely stretch, and heat set to obtain a base film; Step 2: slit the base film, measure the thickness, and perform corona treatment; then coat aluminum oxide on the surface to obtain a primer layer; then coat aluminum to obtain a functional current collector fluid.

[0010] More preferably, in step 1, the temperature during the high-temperature hot melting process is set to 270-300°C, and the time is 1-3 minutes; the heating temperature is 195-205°C, and the time is 4-6 minutes.

[0011] More preferably, in step 1, the total amount of different nickel-containing hydroxide powders added once is 0.4-0.6% of the mass of the hot melt polymer; the total amount of different nickel-containing hydroxide powders added again is 0.1-0.3% of the mass of the mixed polymer.

[0012] More preferably, in step 1, the longitudinal stretching preheating roller is set to a temperature of 63-68°C, the slow stretching roller is set to a temperature of 83-86°C, the fast stretching roller is set to a temperature of 32-38°C, the cooling roller is set to a temperature of 35-45°C, and the longitudinal stretching ratio is set to 2.3-2.8 times; the transverse stretching preheating roller is set to a temperature of 83-87°C, the slow stretching roller is set to a temperature of 93-98°C, and the transverse stretching ratio is set to 3.2-3.7 times.

[0013] More preferably, in step 1, the heat setting temperature is 190-200°C, the time is 3-6 seconds, and after setting, the wind cooling temperature is 43-48°C.

[0014] More preferably, in step 2, the coating of aluminum oxide and aluminum is performed by one of magnetic control or vacuum evaporation; the coating of aluminum is performed by one of magnetic control or vacuum evaporation.

[0015] More preferably, the specific process parameters of the vacuum evaporation are: the film unwinding end tension is controlled at 110-130 N, the winding end tension is controlled at 120-140 N; after the winding trolley enters the evaporation chamber, vacuum is drawn to 4.8×10 -3 ~5.2×10 -3 Pa, the winding trolley is started, the speed is controlled at 290-310 m / min, oxygen is introduced for evaporation, and the vacuum degree is controlled at 4.8×10 -2 ~5.2×10 -2 Pa.

[0016] Compared with the prior art, the present application has the advantages that: The present application introduces different nickel-containing hydroxides: alpha-Ni(OH)2 powder, beta-Ni(OH)2 powder, gamma-NiOOH powder into high-temperature hot-melt polymers to generate NiO with different crystal structures; alpha-Ni(OH)2, beta-Ni(OH)2, gamma-NiOOH are different nickel-containing hydroxides generated at low temperature from nickel salts, and different nickel-containing hydroxides can generate alpha-NiO, beta-NiO, gamma-NiO with different crystal forms by dehydration at high temperature; different crystal structures of NiO promote the crystallization state of the base film generation, and chemical reactions occur between the surface functional groups during the production of the base film and form coordination bonds, effectively increasing the adhesion between the metal layer, the plating layer bonding force and the electrolyte corrosion resistance.

[0017] For the improvement of the adhesion between the primer layer and the base film, different crystal structures of alpha-NiO, beta-NiO, gamma-NiO generated by different nickel-containing hydroxides form chemical bonds between the base film and the primer layer through structural complementation and chemical action, breaking through the simple mechanical combination of traditional evaporation process. When the three are compounded in pairs, a multi-level chemical bond network can be formed between the base film and the primer layer. When alpha-Ni(OH)2 powder and gamma-NiOOH powder are compounded, the regular crystal structure of alpha-NiO formed by high-temperature hot-melt of alpha-Ni(OH)2 powder induces the base film to form large-size, high-orientation crystalline regions, and the amorphous or porous structure of gamma-NiO formed by high-temperature hot-melt of gamma-NiOOH powder promotes the base film to form small-size, high-density microcrystalline nuclei; the rigid crystal lattice of the former provides mechanical support, and the flexible adsorption layer of the latter strengthens the interface adsorption, and the two compounds can refine the grain size and improve the crystallinity, thereby enhancing the physical stability of the base film, and the two compounds construct a "rigid-flexible" dual-functional interface layer that effectively prevents the primer layer from delaminating due to mechanical stress or electrolyte corrosion, greatly enhancing the chemical adhesion between the primer layer and the base film.

[0018] For the aspect of improving the crystallinity of the base film, different crystal structures of α-NiO, β-NiO and γ-NiO promote the crystallization state of the base film generation, increase the crystallinity of the base film to increase the adhesion to the metal layer, and can play a synergistic effect by regulating the crystallization behavior of the base film. α-NiO, β-NiO and γ-NiO will chemically react with the functional groups on the surface of the base film to form coordination bonds, further strengthening the crystalline interface. Different crystal structures of α-NiO, β-NiO and γ-NiO generated by different nickel-containing hydroxide compounding strategies not only enhance the mechanical properties of the base film itself, but also provide a more stable adhesion foundation for the primer layer by increasing the interfacial activity sites and chemical bonding sites, improve the interfacial bonding strength, and meet the long-term stability requirements of high-reliability batteries for current collectors. In summary, by regulating the combination of nickel-containing hydroxides, different crystal structures of α-NiO, β-NiO and γ-NiO are generated to improve the comprehensive performance of the functional current collector. DETAILED DESCRIPTION

[0019] The technical solutions in the embodiments of the present application will be described below in a clear and complete manner. Obviously, the described embodiments are only a part of the embodiments of the present application, not all embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative labor fall within the scope of the present application.

[0020] It should be noted that the following parts are by weight, and there is no special restriction on the purchase of all raw materials involved in the present application. Exemplary raw materials include: in the following embodiments, α-Ni(OH)2(type number: 12054-48-3, provided by Wuhan Jiyesheng Chemical Co., Ltd.), β-Ni(OH)2(type number: 212054-48-6, provided by Wuhan Jiyesheng Chemical Co., Ltd.), γ-NiOOH(type number: 12054-48-10, provided by Wuhan Jiyesheng Chemical Co., Ltd.), polyolefin(POE, CAS: 100-46-9), glass fiber(fiber diameter: 15μm), alumina(CAS: 1344-28-1).

[0021] Example 1: Introduce α-Ni(OH)2and γ-NiOOH powders during the production of the base film, and then perform vacuum evaporation to obtain a functional current collector, including the following steps: Step 1: 40 parts of polyethylene terephthalate, 20 parts of glass fiber, 10 parts of polyolefin, and 10 parts of 2,6-dibromophenylene ether are mixed, dried, and then hot melted at 280°C to obtain a hot melt polymer; α-Ni(OH)2and γ-NiOOH powders (mass ratio 1:1) are added once, with an amount of 0.5%wt of the hot melt polymer, and the temperature is set to 300°C for 2 min of melting heating to obtain a mixed polymer; it is transferred to a mold, and α-Ni(OH)2and γ-NiOOH powders (mass ratio 1:1) are added twice to cover the surface of the mixed polymer, with an amount of 0.2%wt of the mixed polymer, and heated at 200°C for 5 min; longitudinal and transverse stretching is performed, the longitudinal stretching preheating roller is set to 65°C, the slow stretching roller is set to 85°C, the fast stretching roller is set to 35°C, the cooling roller is set to 35°C and 45°C, the longitudinal stretching ratio is set to 2.5 times, the transverse stretching preheating roller is set to 85°C, the slow stretching roller is set to 95°C, the longitudinal stretching ratio is set to 3.5 times, the heat setting temperature is set to 195°C, the time is set to 4 s, and after setting, air cooling is performed to 45°C to obtain a base film; Step 2: The base film is cut, measured in thickness, and subjected to corona treatment; then aluminum oxide is vacuum evaporated on the surface of the base film, with the film end tension controlled at 110N, the winding end tension controlled at 120N, the winding trolley entering the evaporation chamber, the vacuum degree extracted to 5×10 -3 Pa, the winding trolley speed controlled at 300m / min, oxygen introduced at the same time, and aluminum oxide evaporated on the surface of the base film at a vacuum degree of 5×10 -2 Pa to obtain a primer layer; then aluminum is vacuum evaporated to obtain a functional current collector.

[0022] Example 2: β-Ni(OH)2and γ-NiOOH powders are introduced during the production of the base film, and a functional current collector is obtained by vacuum evaporation, including the following steps: Step 1: 40 parts of polyethylene terephthalate, 20 parts of glass fiber, 10 parts of polyolefin, and 10 parts of 2,6-dibromophenylene ether are mixed, dried, and then subjected to high-temperature hot melting at 280°C to obtain a hot-melt polymer; β-Ni(OH)2and γ-NiOOH powders (mass ratio 1:1) are added once, with an amount of 0.5%wt of the hot-melt polymer, and the temperature is set to 300°C for 2 min of melting heating to obtain a mixed polymer; the mixed polymer is transferred to a mold, and β-Ni(OH)2and γ-NiOOH powders (mass ratio 1:1) are added twice to cover the surface of the mixed polymer, with an amount of 0.2%wt of the mixed polymer, and heated at 200°C for 5 min; longitudinal and transverse stretching is performed, the longitudinal stretching preheating roller is set to 65°C, the slow stretching roller is set to 85°C, the fast stretching roller is set to 35°C, the cooling roller is set to 35°C and 45°C, and the longitudinal stretching ratio is set to 2.5 times; the transverse stretching preheating roller is set to 85°C, the slow stretching roller is set to 95°C, and the longitudinal stretching ratio is set to 3.5 times, the heat setting temperature is 195°C, the time is 4s, and the wind cooling temperature after setting is 45°C to obtain a base film; Step 2: The base film is cut, measured in thickness, and subjected to corona treatment; then aluminum oxide is vacuum evaporated on the surface of the base film, with the film end tension controlled at 110N and the winding end tension controlled at 120N, the winding trolley enters the evaporation chamber, vacuum is drawn to 5×10 -3 Pa, the winding trolley speed is controlled at 300m / min, oxygen is introduced, and aluminum oxide is evaporated on the surface of the base film at a vacuum degree of 5×10 -2 Pa to obtain a primer layer; then aluminum is vacuum evaporated to obtain a functional current collector.

[0023] Example 3: α-Ni(OH)2powder and β-Ni(OH)2powder are introduced during the production of the base film, and a functional current collector is obtained by vacuum evaporation, including the following steps: Step 1: Mix 40 parts polyethylene terephthalate, 20 parts glass fiber, 10 parts polyolefin, and 10 parts 2,6-dibromophenylene ether, dry the mixture, and then heat-melt it at 280℃ to obtain a hot-melt polymer. Add α-Ni(OH)₂ and β-Ni(OH)₂ powders (mass ratio 1:1) at a rate of 0.5% wt of the hot-melt polymer, set the temperature to 300℃, and heat for 2 minutes to obtain a mixed polymer. Transfer this mixture to a mold, and add α-Ni(OH)₂ and β-Ni(OH)₂ a second time. Powder (mass ratio 1:1) was added to the surface of the mixed polymer at a rate of 0.2% wt of the mixed polymer, and heated at 200℃ for 5 min. Longitudinal and transverse stretching were then performed. For longitudinal stretching, the preheating roller temperature was set to 65℃, the slow stretching roller temperature to 85℃, the fast stretching roller temperature to 35℃, and the cooling roller temperatures to 35℃ and 45℃, with a longitudinal stretching ratio of 2.5. For transverse stretching, the preheating roller temperature was set to 85℃, the slow stretching roller temperature to 95℃, the longitudinal stretching ratio to 3.5, the heat setting temperature was 195℃, and the time was 4 s. After heat setting, the film was air-cooled to 45℃ to obtain the base film. Step 2: The base film is slit, thickness measured, and corona-treated; then, alumina is vacuum-deposited onto its surface, with the tension at the unwinding end controlled at 110N and the tension at the winding end controlled at 120N. The winding trolley enters the evaporation chamber, and a vacuum of 5×10⁻⁶ is applied. -3 Pa, the speed of the winding trolley is controlled at 300 m / min, and oxygen is introduced simultaneously at 5 × 10 -2 Alumina is vapor-deposited onto the base film surface under a vacuum of Pa to obtain the underlayer; then aluminum is vapor-deposited under vacuum to obtain the functional current collector.

[0024] Example 4: Introducing α-Ni(OH)2 powder into the base film production process, followed by vacuum evaporation to deposit a functional current collector, including the following steps: Step 1: Mix 40 parts polyethylene terephthalate, 20 parts glass fiber, 10 parts polyolefin, and 10 parts 2,6-dibromophenylene ether, dry the mixture, and then heat-melt it at 280℃ to obtain a hot-melt polymer. Add α-Ni(OH)₂ powder once, at a weight of 0.5% wt of the hot-melt polymer, and heat at 300℃ for 2 minutes to obtain a mixed polymer. Transfer the mixture to a mold, and then add α-Ni(OH)₂ powder a second time to cover the mixed polymer. The surface was treated with 0.2%wt of the mixed polymer and heated at 200℃ for 5 min. Longitudinal and transverse stretching were then performed. For longitudinal stretching, the preheating roller was set to 65℃, the slow stretching roller to 85℃, the fast stretching roller to 35℃, and the cooling rollers to 35℃ and 45℃, with a longitudinal stretching ratio of 2.5. For transverse stretching, the preheating roller was set to 85℃, the slow stretching roller to 95℃, the longitudinal stretching ratio to 3.5, the heat setting temperature was 195℃, and the time was 4 s. After heat setting, the film was air-cooled to 45℃ to obtain the base film. Step 2: The base film is slit, thickness measured, and corona-treated; then, alumina is vacuum-deposited onto its surface, with the tension at the unwinding end controlled at 110N and the tension at the winding end controlled at 120N. The winding trolley enters the evaporation chamber, and a vacuum of 5×10⁻⁶ is applied. -3 Pa, the speed of the winding trolley is controlled at 300 m / min, and oxygen is introduced simultaneously at 5 × 10 -2 Alumina is vapor-deposited onto the base film surface under a vacuum of Pa to obtain the underlayer; then aluminum is vapor-deposited under vacuum to obtain the functional current collector.

[0025] Example 5: Introducing β-Ni(OH)2 powder into the base film production process, followed by vacuum evaporation to deposit a functional current collector, including the following steps: Step 1: Mix 40 parts polyethylene terephthalate, 20 parts glass fiber, 10 parts polyolefin, and 10 parts 2,6-dibromophenylene ether, dry the mixture, and then heat-melt it at 280℃ to obtain a hot-melt polymer. Add β-Ni(OH)2 powder once, at an amount of 0.5% wt of the hot-melt polymer, and set the temperature to 300℃. Melt and heat for 2 minutes to obtain a mixed polymer. Transfer the mixture to a mold, and add β-Ni(OH)2 powder a second time to cover the mixed polymer. The surface was treated with 0.2%wt of the mixed polymer and heated at 200℃ for 5 min. Longitudinal and transverse stretching were then performed. For longitudinal stretching, the preheating roller was set to 65℃, the slow stretching roller to 85℃, the fast stretching roller to 35℃, and the cooling rollers to 35℃ and 45℃, with a longitudinal stretching ratio of 2.5. For transverse stretching, the preheating roller was set to 85℃, the slow stretching roller to 95℃, the longitudinal stretching ratio to 3.5, the heat setting temperature was 195℃, and the time was 4 s. After heat setting, the film was air-cooled to 45℃ to obtain the base film. Step 2: The base film is slit, thickness measured, and corona-treated; then, alumina is vapor-deposited onto its surface, with the tension at the unwinding end controlled at 110N and the tension at the winding end controlled at 120N. The winding trolley enters the evaporation chamber, and a vacuum of 5×10⁻⁶ is applied. -3 Pa, the speed of the winding trolley is controlled at 300 m / min, and oxygen is introduced simultaneously at 5 × 10 -2 Alumina is vapor-deposited onto the base film surface under a vacuum of Pa to obtain the underlayer; then aluminum is vapor-deposited under vacuum to obtain the functional current collector.

[0026] Example 6: Introducing γ-NiOOH powder into the base film production process, followed by vacuum evaporation to deposit a functional current collector, including the following steps: Step 1: Mix 40 parts polyethylene terephthalate, 20 parts glass fiber, 10 parts polyolefin, and 10 parts 2,6-dibromophenylene ether, dry the mixture, and then heat-melt it at 280℃ to obtain a hot-melt polymer. Add γ-NiOOH powder once, at an amount of 0.5% wt of the hot-melt polymer, and set the temperature to 300℃. Melt and heat for 2 minutes to obtain a mixed polymer. Transfer the mixture to a mold, and add γ-NiOOH powder a second time to cover the surface of the mixed polymer. The amount added was 0.2%wt of the mixed polymer, and heated at 200℃ for 5 min; longitudinal stretching and transverse stretching were performed. The longitudinal stretching preheating roller was set at 65℃, the slow stretching roller at 85℃, the fast stretching roller at 35℃, and the cooling rollers at 35℃ and 45℃, with a longitudinal stretching ratio of 2.5; the transverse stretching preheating roller was set at 85℃, the slow stretching roller at 95℃, the longitudinal stretching ratio of 3.5, the heat setting temperature was 195℃, and the time was 4s. After setting, it was air-cooled to 45℃ to obtain the base film. Step 2: The base film is slit, thickness measured, and corona-treated; then, alumina is vapor-deposited onto its surface, with the tension at the unwinding end controlled at 110N and the tension at the winding end controlled at 120N. The winding trolley enters the evaporation chamber, and a vacuum of 5×10⁻⁶ is applied. -3 Pa, the speed of the winding trolley is controlled at 300 m / min, and oxygen is introduced simultaneously at 5 × 10 -2 Alumina is vapor-deposited onto the base film surface under a vacuum of Pa to obtain the underlayer; then aluminum is vapor-deposited under vacuum to obtain the functional current collector.

[0027] Comparative Example 1: Based on Example 1, the composition of the base film was adjusted by adding conventional NiO powder. The specific steps are as follows: Step 1: Mix 40 parts polyethylene terephthalate, 20 parts glass fiber, 10 parts polyolefin, and 10 parts 2,6-dibromophenylene ether, dry the mixture, and then heat-melt it at 280℃ to obtain a hot-melt polymer. Add conventional NiO powder once, at a rate of 0.5% wt of the hot-melt polymer, and heat at 300℃ for 2 minutes to obtain a mixed polymer. Transfer this mixture to a mold, and then add conventional NiO powder a second time to cover the surface of the mixed polymer. The feed amount is 0.2%wt of the hot melt polymer, and it is heated at 200℃ for 5 min. Longitudinal stretching and transverse stretching are performed. For longitudinal stretching, the preheating roller temperature is set to 65℃, the slow stretching roller temperature is 85℃, the fast stretching roller temperature is 35℃, and the cooling roller temperature is 35℃ and 45℃. The longitudinal stretching ratio is set to 2.5 times. For transverse stretching, the preheating roller temperature is set to 85℃, the slow stretching roller temperature is 95℃, the longitudinal stretching ratio is set to 3.5 times, the heat setting temperature is 195℃, the time is 4s, and after setting, it is air-cooled to 45℃ to obtain the base film. Step 2: The base film is slit, thickness measured, and corona-treated; then, alumina is vapor-deposited onto its surface, with the tension at the unwinding end controlled at 110N and the tension at the winding end controlled at 120N. The winding trolley enters the evaporation chamber, and a vacuum of 5×10⁻⁶ is applied. -3 Pa, the speed of the winding trolley is controlled at 300 m / min, and oxygen is introduced simultaneously at 5 × 10 -2 Alumina is vapor-deposited onto the base film surface under a vacuum of Pa to obtain the underlayer; then aluminum is vapor-deposited under vacuum to obtain the functional current collector.

[0028] Comparative Example 2: Based on Example 1, the composition of the base film was adjusted without adding metal oxides. The specific steps are as follows: Step 1: Mix 40 parts polyethylene terephthalate, 20 parts glass fiber, 10 parts polyolefin, and 10 parts 2,6-dibromophenylene ether, dry the mixture, and then heat-melt it at 280℃ to obtain a hot-melt polymer. Perform longitudinal and transverse stretching. For longitudinal stretching, set the preheating roller temperature to 65℃, the slow stretching roller temperature to 85℃, the fast stretching roller temperature to 35℃, and the cooling roller temperatures to 35℃ and 45℃, with a longitudinal stretching ratio of 2.5. For transverse stretching, set the preheating roller temperature to 85℃, the slow stretching roller temperature to 95℃, the longitudinal stretching ratio to 3.5, the heat setting temperature to 195℃, and the time to 4s. After heat setting, air-cool to 45℃ to obtain the base film. Step 2: The base film is slit, thickness measured, and corona-treated; then, alumina is vacuum-deposited onto its surface, with the tension at the unwinding end controlled at 110N and the tension at the winding end controlled at 120N. The winding trolley enters the evaporation chamber, and a vacuum of 5×10⁻⁶ is applied. -3 Pa, the speed of the winding trolley is controlled at 300 m / min, and oxygen is introduced simultaneously at 5 × 10 -2 Alumina is vapor-deposited onto the base film surface under a vacuum of Pa to obtain the underlayer; then aluminum is vapor-deposited under vacuum to obtain the functional current collector.

[0029] Performance testing: The above functional current collectors were immersed in electrolyte and the peel force was tested. (1) Electrolyte immersion: The functional current collectors were cut into 6×8cm pieces and packaged with aluminum-plastic film, with 2 composite films in each bag. Afterwards, 10mL of ternary electrolyte was injected into each bag of samples in the glove box and sealed. After different number of days (1 / 3 / 7 / 15 / 30), the samples were taken out and the surface electrolyte was cleaned by ethanol immersion in the fume hood. (2) Peel force test: Take a test sample with a size of 15×100mm, stick 3M-9080A-15mm tape on a stainless steel plate, then evenly stick the test sample on double-sided tape, use a 2kg standard small pressure roller to squeeze back and forth twice, then stick 3M-9080A-14mm tape on the sample surface, use a 2kg standard small pressure roller to squeeze back and forth twice, then take the pressed sample to the tensile testing machine and stretch it at 180°, speed 100mm / min, width set to 15mm, and take the maximum value of the result.

[0030] Table 1. Relevant data on performance testing of examples and comparative examples

[0031] Conclusion: Comparing the performance test data of the examples and comparative examples, it can be seen from Examples 1-6 that while using a single NiO with different crystal structures can promote the crystallization state of the base film and increase its crystallinity, thereby increasing its adhesion to the metal layer, it is significantly less effective than the combination of the three in pairs. Among the examples of the two-pair combinations, the chemical bond formed between the mixed powder of α-Ni(OH)2 and γ-NiOOH and the base film is the strongest, and its resistance to electrolyte corrosion is also the strongest. Because the α-NiO formed by α-Ni(OH)2 has high stability, its stable lattice provides mechanical support for the base film and inhibits electrolyte corrosion. The interfacial expansion caused by infiltration, and the γ-NiO formed by γ-NiOOH, have high specific surface area and adsorption characteristics. The two form a bifunctional interfacial layer of "rigid framework-flexible adsorption". The combination of the two greatly promotes the crystal formation of the base film. The oxide and surface functional groups react chemically to form coordination bonds, which increases the coating adhesion and resistance to electrolyte corrosion. With the addition of oxide, the chemical bonds formed enhance the electrolyte corrosion resistance. After immersion in electrolyte for 30 days, the peeling force is still very high. This combination can maximize the adhesion between the substrate and the base film, which can greatly improve the application of functional current collectors in the cell.

[0032] Compared to Examples 1-6, Comparative Example 1, with the addition of only conventional NiO, showed a significant decrease in peel strength after 3 days of immersion during the base film production process, and the coating detached directly after 7 days of immersion. In Comparative Example 2, without the addition of metal oxides, the peel strength of the coating decreased sharply with longer immersion time during base film production, leading to coating detachment. This demonstrates that NiO with different crystal structures can effectively form interfacial chemical bonds, strengthening the bond between the base film and the substrate, and resisting electrochemical environmental damage. In summary, this invention, through a compounding strategy to adjust the NiO crystal structure combination, achieves multi-dimensional optimization of interfacial bonding strength and corrosion resistance, comprehensively improving the peel strength of the functional current collector base film and the bond strength between the base film and the substrate.

[0033] Finally, it should be noted that the above descriptions are merely preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A functional current collector with high bonding strength for the underlayer, characterized in that: The functional current collector includes a base film and an underlayer. The base film contains nickel oxide with different crystal structures, including one or more of α-NiO, β-NiO, and γ-NiO.

2. The functional current collector with high bonding strength for layering as described in claim 1, characterized in that: The thickness of the base film is 2~6μm, and the thickness of the underlayer is 0.1~2μm.

3. A functional current collector with high bonding strength for layering as described in claim 1, characterized in that: The different crystalline nickel oxides are composed of two of α-NiO, β-NiO, and γ-NiO, with a mass ratio of 1:

1.

4. A functional manifold with high bonding strength for layering, as described in claim 1, characterized in that: The preparation of the functional current collector includes the following steps: Step 1: Dry the base film raw material and heat-melt it at high temperature to obtain a hot-melt polymer; add different nickel hydroxide powders at one time, stir, melt and heat to obtain a mixed polymer; transfer it to a mold, add different nickel hydroxide powders at another time to cover the surface of the mixed polymer; heat, stretch longitudinally, stretch transversely and heat-set to obtain the base film; Step 2: Cut the base film, measure its thickness, and corona discharge it; then coat its surface with aluminum oxide to obtain the underlayer; then coat it with aluminum to obtain the functional current collector.

5. A functional current collector with high bonding strength for layering according to claim 4, characterized in that: In step 1, during the high-temperature hot melting process, the temperature is set to 270~300℃ and the time is 1~3 minutes; the heating temperature is 195~205℃ and the time is 4~6 minutes.

6. A functional current collector with high bonding strength for layering as described in claim 4, characterized in that: In step 1, the total amount of different nickel hydroxides added in the first addition is 0.4 to 0.6% of the mass of the hot melt polymer; the total amount of different nickel hydroxides added in the second addition is 0.1 to 0.3% of the mass of the mixed polymer.

7. A functional current collector with high bonding strength for layering as described in claim 4, characterized in that: In step 1, the longitudinal stretching preheating roller is set to a temperature of 63~68℃, the slow stretching roller to a temperature of 83~86℃, the fast stretching roller to a temperature of 32~38℃, and the cooling roller to a temperature of 35~45℃, with a longitudinal stretching ratio of 2.3~2.8 times; the transverse stretching preheating roller is set to a temperature of 83~87℃, the slow stretching roller to a temperature of 93~98℃, with a longitudinal stretching ratio of 3.2~3.7 times.

8. A functional current collector with high bonding strength for layering according to claim 4, characterized in that: In step 1, the heat setting temperature is 190~200℃, the time is 3~6 seconds, and after setting, it is air-cooled to 43~48℃.

9. A functional current collector with high bonding strength for layering according to claim 4, characterized in that: In step 2, the aluminum oxide coating is either magnetron sputtering or vacuum evaporation; the aluminum coating method is either magnetron sputtering or vacuum evaporation.

10. A functional manifold with high bonding strength for layering, as described in claim 9, characterized in that: The specific process parameters for the vacuum evaporation are as follows: the tension at the unwinding end is controlled at 110~130N, and the tension at the winding end is controlled at 120~140N; after the winding carriage enters the evaporation chamber, a vacuum of 4.8×10⁻⁶ is applied. -3 ~5.2×10 -3 Pa, start the winding carriage, control the speed at 290~310m / min, and simultaneously start the oxygen intake for vapor deposition, controlling the vacuum degree at 4.8×10 -2 ~5.2×10 -2 Pa.

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