A composite material, a method of manufacture, a current collector high pressure corrosion resistant coating and use thereof

Abstract

The application provides a composite material, a preparation method, a high-pressure corrosion-resistant coating of a current collector and application thereof, and the composite material comprises a carrier, the surface of the carrier is dispersed with Al2O3 nanoparticles, and the surface of the Al2O3 nanoparticles is coated with graphene oxide. The composite material of the application is used for preparing a high-pressure corrosion-resistant coating, Al2O3 dispersed on the surface of the carrier can form a three-dimensional anticorrosion barrier in the coating, under the synergistic effect of graphene oxide (GO) and Al2O3, the coating has a shielding corrosion effect on the corrosion medium, and thus, the coating has excellent corrosion resistance and long service life in the high-voltage charging and discharging process of a lithium battery. The application further provides a preparation method of the composite material, a high-pressure corrosion-resistant coating of a current collector and application thereof.

Description

Technical Field

[0001] This invention belongs to the field of electrode material technology, specifically relating to a composite material, its preparation method, a high-pressure corrosion-resistant coating for current collectors, and its application. Background Technology

[0002] Lithium-ion batteries are widely used in various industries, and the performance requirements for them are constantly increasing. High safety and high energy density have become the research directions for the development of next-generation lithium-ion batteries. Developing a high-voltage positive electrode is one of the effective ways to achieve high-energy-density lithium-ion batteries. However, the commercially available electrolytes commonly used in lithium-ion batteries currently contain lithium salt LiPF6. This lithium salt easily decomposes in water to generate HF, which corrodes and destroys the structural stability of the positive electrode current collector under high voltage, causing battery capacity decay. Furthermore, volatile and flammable carbonate solvents under high voltage pose serious safety hazards to lithium-ion batteries.

[0003] Under high pressure, achieving corrosion resistance of the positive electrode current collector in lithium-ion batteries is a current research focus. One method is to improve the stability of the positive electrode current collector under high voltage by preparing a high-pressure corrosion-resistant coating through surface protection technology. This protective layer is characterized by its simple and convenient preparation, low cost, high pressure resistance, and long-lasting effect. Therefore, high-pressure corrosion-resistant coatings have excellent advantages in improving the corrosion resistance of lithium-ion battery positive electrode current collectors. Currently used preparation methods mainly include surface modification technologies such as magnetron sputtering, chemical plating, and organic coating.

[0004] Organic coating technology is the most effective, and it is also less expensive than techniques such as magnetron sputtering and electroless plating. However, the performance of the resulting coatings is not ideal and still needs further improvement. Summary of the Invention

[0005] The present invention aims to at least solve one of the aforementioned technical problems existing in the prior art. To this end, the present invention provides a composite material, the current collector coating prepared from this composite material exhibits excellent corrosion resistance and long lifespan during high-voltage charging and discharging of lithium batteries.

[0006] The present invention also provides a method for preparing a composite material.

[0007] The present invention also provides a high-pressure corrosion-resistant coating for current collectors.

[0008] The present invention also provides a battery positive electrode.

[0009] The present invention also provides a lithium-ion battery.

[0010] A first aspect of the present invention provides a composite material comprising a carrier having Al2O3 nanoparticles dispersed on its surface, the Al2O3 nanoparticles being coated with graphene oxide.

[0011] One technical solution of the present invention relating to composite materials has at least the following beneficial effects:

[0012] Organic coatings can be effectively improved by adding different fillers to enhance the performance of composite materials, thereby increasing the chemical and physical stability of the coating itself to meet the stringent requirements of lithium battery cathode current collectors under high voltage. Common fillers are mainly inorganic nanomaterials, and oxide ceramic powder particles and two-dimensional layered materials are often added to the coating as fillers to improve the corrosion resistance of the cathode current collector under high voltage. In the composite material of this invention, Al2O3 nanoparticles are dispersed on the carrier surface, and the surface of the Al2O3 nanoparticles is coated with graphene oxide. When this composite material is used to prepare a high-voltage corrosion-resistant coating, the Al2O3 dispersed on the carrier surface can form a three-dimensional anti-corrosion barrier inside the coating. Under the synergistic effect of graphene oxide (GO) and Al2O3, the coating will have a shielding effect against corrosive media. Therefore, the coating exhibits excellent corrosion resistance and long life during the high-voltage charging and discharging process of lithium batteries.

[0013] According to some embodiments of the present invention, the carrier comprises conductive carbon black.

[0014] Conductive carbon black is a carbon black material with excellent electrical conductivity. Adding an appropriate amount of conductive carbon black to the current collector coating can significantly improve the coating's conductivity, allowing current to be transferred more effectively from the electrode current collector to the electrochemically active material. Furthermore, in electrochemical energy storage and conversion devices (such as lithium-ion batteries and fuel cells), the catalyst on the electrode is a key factor in promoting electrochemical reactions. As a component of the current collector coating, conductive carbon black can act as a carrier, increasing surface area and improving reaction efficiency, thereby increasing energy conversion efficiency. Moreover, in batteries, the current collector coating is used to collect current and transfer it to the entire electrode surface. The addition of conductive carbon black helps achieve a uniform current distribution, avoiding current concentration in localized areas and reducing losses and safety risks caused by uneven current distribution. Finally, especially during charge-discharge cycles, the current collector may be subject to mechanical stress. The addition of conductive carbon black can also increase the mechanical strength and stability of the current collector coating, which is crucial for the long-term stable operation of electrochemical devices.

[0015] A second aspect of the present invention provides a method for preparing the composite material, comprising the following steps: dispersing dopamine hydrochloride-modified graphene oxide in a solvent, adding silane coupling agent-modified Al2O3 / carrier composite material, stirring, and then washing and drying the product to obtain the composite material.

[0016] One technical solution of the present invention relating to the preparation method of composite materials has at least the following beneficial effects:

[0017] The preparation method of the present invention does not require expensive equipment and complex process control, the reaction conditions are not harsh, the raw materials are readily available, the production cost is low, and it is easy to industrialize.

[0018] GO was modified with dopamine hydrochloride to obtain dopamine hydrochloride-modified graphene oxide (denoted as DA-GO). Using conductive carbon black as a carrier, Al2O3 particles were grown in situ on its surface to obtain a powder dispersed on the carrier surface (denoted as Al2O3@S). Then, a silane coupling agent was used to graft and modify the surface of the Al2O3@S powder to obtain a silane coupling agent-modified Al2O3 / carrier composite material (denoted as K-Al2O3@S). DA-GO and K-Al2O3@S attracted each other electrostatically and assembled to form the composite material of this invention (denoted as DA-GO / K-Al2O3@S), a powder filler.

[0019] The preparation method of the present invention achieves dispersion and compatibility of GO and Al2O3.

[0020] According to some embodiments of the present invention, the preparation method of the dopamine hydrochloride modified graphene oxide includes the following steps: adding dopamine hydrochloride to a graphene oxide dispersion, stirring, and then washing and drying the product to obtain the product.

[0021] According to some embodiments of the present invention, the preparation method of the dopamine hydrochloride modified graphene oxide includes the following steps:

[0022] Add 1.2-1.5g of tris(hydroxymethyl)aminomethane (Tris) to 800-1000mL of deionized water and titrate the solution with dilute hydrochloric acid to set the pH to 8.5;

[0023] Adding 0.1-0.2g of GO to the buffer solution and sonicating for 40-60 minutes will clearly show that the GO has been completely and uniformly dispersed.

[0024] Add 0.1-0.2g of powdered dopamine hydrochloride to the GO dispersion, and stir the mixture at 30-60℃ and 1000-2000r / min for 12-24 hours. The solution will change from brownish-yellow to black.

[0025] The solution was centrifuged at 3000-4500 rpm, then washed three times with ethanol and deionized water, and the resulting product was vacuum dried to obtain the DA-GO composite material.

[0026] According to some embodiments of the present invention, the preparation method of the silane coupling agent modified Al2O3 / carrier composite material includes the following steps:

[0027] (1) After dispersing Al(NO3)3·9(H2O) and surfactant in a solvent, add the carrier and Li2CO3, react and calcine to obtain Al2O3 / carrier composite material;

[0028] (2) The Al2O3 / carrier composite material is grafted and modified by adding a silane coupling agent to obtain the silane coupling agent modified Al2O3 / carrier composite material.

[0029] The main function of Al(NO3)3·9(H2O) is to provide an aluminum source, which is a raw material for the subsequent formation of Al2O3.

[0030] Li2CO3 reacts with Al(NO3)3·9(H2O) to form aluminum carbonate, which is a precursor for the subsequent formation of Al2O3.

[0031] The silane coupling agent is mainly grafted onto Al2O3 to avoid agglomeration and facilitates uniform binding and dispersion with DA-GO in the subsequent process.

[0032] According to some embodiments of the present invention, the silane coupling agent includes KH550.

[0033] According to some embodiments of the present invention, the surfactant comprises sodium dodecylbenzenesulfonate.

[0034] Surfactants play a role in dispersing intermediate and final reaction products and preventing agglomeration during the preparation of Al2O3@S powder.

[0035] According to some embodiments of the present invention, the calcination temperature is 400°C to 700°C.

[0036] According to some embodiments of the present invention, the preparation method of the silane coupling agent modified Al2O3 / carrier composite material includes the following steps:

[0037] (1) Weigh 0.6-0.8g of aluminum nitrate nonahydrate Al(NO3)3·9(H2O), 0.2-0.3g of lithium carbonate (Li2CO3), 0.3-0.4g of sodium dodecylbenzenesulfonate, and then weigh 1.2-1.5g of conductive carbon black (SuperP, abbreviated as "S") material;

[0038] Dissolve aluminum nitrate nonahydrate and sodium dodecylbenzenesulfonate in deionized water, then sonicate for 2-10 minutes. Add conductive carbon black (SuperP) material to the solution and continue sonicating for another 2-10 minutes.

[0039] Then transfer the above mixture to a mixer and stir rapidly for 0.5-1 hour, and add lithium carbonate solution dropwise at a rate of 1.5 seconds per drop.

[0040] After the dripping is complete, stir for 1 hour, then filter and dry, and then calcine at a certain temperature (400℃-700℃) for a certain time to obtain Al2O3@S composite material;

[0041] (2) Dry the Al2O3@S composite material at 90-120℃ for 2-4 hours;

[0042] Weigh 1.2-1.5g of Al2O3@S composite material into a beaker, pour in 75% anhydrous ethanol solution, and add an appropriate amount of acetic acid to adjust the pH of the solution to 5-7.

[0043] Add 0.24-0.3g of silane coupling agent (KH550) and sonicate for about 1-2 hours;

[0044] Then, use a high-speed mixer to stir at 50-80℃ for 4-6 hours at a stirring speed of 500-1000 r / min.

[0045] After the reaction was complete, the reactants were removed, centrifuged, washed, and then dried in a vacuum oven for 12-24 hours to obtain the K-Al2O3@S composite material.

[0046] According to some embodiments of the present invention, the method for preparing the composite material is as follows:

[0047] Add the DA-GO composite material to 100 mL of deionized water, and then add 1.2-1.5 g of K-Al2O3 / @S to the mixture;

[0048] Magnetic stirring 24;

[0049] The mixture was centrifuged, filtered, washed, and vacuum dried to obtain the DA-GO / K-Al2O3@S composite material.

[0050] A third aspect of the present invention provides a high-pressure corrosion-resistant coating for a current collector, the components of which include the aforementioned composite material.

[0051] One of the technical solutions of the present invention regarding the high-pressure corrosion-resistant coating for current collectors has at least the following beneficial effects:

[0052] The high-pressure corrosion-resistant coating for current collectors of the present invention uses the composite material of the present invention as a filler, wherein Al2O3 nanoparticles are dispersed on the surface of the carrier, and the surface of the Al2O3 nanoparticles is coated with graphene oxide. When the composite material is used to prepare the high-pressure corrosion-resistant coating, the Al2O3 dispersed on the surface of the carrier can form a three-dimensional anti-corrosion barrier inside the coating. Under the synergistic effect of graphene oxide (GO) and Al2O3, the coating will have the effect of shielding corrosion from corrosive media. Thus, the coating exhibits excellent corrosion resistance and long life during the high-voltage charging and discharging process of lithium batteries.

[0053] According to some embodiments of the present invention, the components of the high-pressure corrosion-resistant coating for the current collector also include a conductive agent and a binder.

[0054] DA-GO / K-Al2O3@S, combined with conductive agents, binders, and solvents, can form a protective high-voltage corrosion-resistant coating when coated on the positive electrode current collector. DA-GO / K-Al2O3@S can form a three-dimensional corrosion barrier within the coating. Through the synergistic effect of GO and Al2O3, this coating provides a barrier against corrosive media. Benefiting from these advantages, the coating exhibits excellent corrosion resistance and long lifespan during the high-voltage charging and discharging process of lithium batteries.

[0055] According to some embodiments of the present invention, the thickness of the high-pressure corrosion-resistant coating on the current collector is 5 μm to 10 μm.

[0056] According to some embodiments of the present invention, the positive current collector is an aluminum foil current collector.

[0057] According to some embodiments of the present invention, the method for preparing a high-pressure corrosion-resistant coating for a current collector is as follows:

[0058] A slurry is prepared by mixing 1.2-1.5g of DA-GO / K-Al2O3@S powder, 0.15-0.2g of polyvinylidene fluoride (PVDF), 0.15-0.2g of conductive carbon black (SuperP), and 3-5mL of methylpyrrolidone (NMP). This slurry is then coated onto the surface of the positive electrode current collector aluminum foil, vacuum dried, and rolled to form a high-pressure corrosion-resistant coating with a thickness of 10-15μm on the aluminum foil surface.

[0059] The above process can produce a high-pressure corrosion-resistant coating in the positive electrode current collector, which has excellent corrosion resistance.

[0060] A fourth aspect of the present invention provides a battery positive electrode comprising the aforementioned current collector high-pressure corrosion-resistant coating.

[0061] One of the technical solutions of the present invention concerning the positive electrode of a battery has at least the following beneficial effects:

[0062] The positive electrode of the battery of the present invention, having contained the high-pressure corrosion-resistant coating for the current collector of the present invention, thus possesses at least all the technical effects of the high-pressure corrosion-resistant coating for the current collector, specifically:

[0063] The positive electrode of the battery of the present invention has a high-pressure corrosion-resistant coating on its current collector using the composite material of the present invention as filler. Al2O3 nanoparticles are dispersed on the surface of the carrier, and the surface of the Al2O3 nanoparticles is coated with graphene oxide. When the composite material is used to prepare the high-pressure corrosion-resistant coating, the Al2O3 dispersed on the surface of the carrier can form a three-dimensional anti-corrosion barrier inside the coating. Under the synergistic effect of graphene oxide (GO) and Al2O3, the coating will have the effect of shielding corrosion from corrosive media. As a result, the lithium battery using the positive electrode of the present invention exhibits excellent corrosion resistance and long life during high-voltage charging and discharging.

[0064] A fifth aspect of the present invention provides a lithium-ion battery, comprising the current collector high-pressure corrosion-resistant coating or the battery positive electrode.

[0065] The lithium-ion battery of the present invention, by containing the current collector high-voltage corrosion-resistant coating or the battery positive electrode of the present invention, thereby possesses at least all the technical effects of the current collector high-voltage corrosion-resistant coating or the battery positive electrode, specifically:

[0066] The lithium-ion battery of the present invention uses the composite material of the present invention as a filler for the high-pressure corrosion-resistant coating of the current collector on the positive electrode. Al2O3 nanoparticles are dispersed on the surface of the carrier, and the surface of the Al2O3 nanoparticles is coated with graphene oxide. When the composite material is used to prepare the high-pressure corrosion-resistant coating, the Al2O3 dispersed on the surface of the carrier can form a three-dimensional anti-corrosion barrier inside the coating. Under the synergistic effect of graphene oxide (GO) and Al2O3, the coating will have the effect of shielding corrosion from corrosive media. Therefore, the lithium battery of the present invention exhibits excellent corrosion resistance and long life during high-voltage charging and discharging. Attached Figure Description

[0067] Figure 1 This is a microscopic morphology diagram of Al2O3 particles growing in situ on the surface of conductive carbon black.

[0068] Figure 2 This is a microscopic morphology diagram of DA-GO coated on the surface of Al2O3 particles.

[0069] Figure 3 The constant current polarization curves are shown for the positive current collector (aluminum foil) surface with a high-pressure corrosion-resistant coating and the positive current collector (aluminum foil).

[0070] Figure 4The image shows the constant potential polarization curves of the positive current collector (aluminum foil) with a high-voltage corrosion-resistant coating.

[0071] Figure 5 The results are from the first three CV cycle tests of the positive electrode current collector (aluminum foil) with a high-pressure corrosion-resistant coating.

[0072] Figure 6 A comparison of impedance spectra of the positive electrode current collector (aluminum foil) with a high-pressure corrosion-resistant coating and the positive electrode current collector (aluminum foil).

[0073] Figure 7 The results are from 100 constant current charge-discharge cycles on the surface of the positive electrode current collector (aluminum foil) with a high-voltage corrosion-resistant coating. Detailed Implementation

[0074] The following are specific embodiments of the present invention, and the technical solutions of the present invention will be further described in conjunction with the embodiments, but the present invention is not limited to these embodiments.

[0075] In some embodiments of the present invention, the present invention provides a composite material comprising a carrier, wherein Al2O3 nanoparticles are dispersed on the surface of the carrier, and the surface of the Al2O3 nanoparticles is coated with graphene oxide.

[0076] It is understandable that organic coatings can effectively improve the performance of composite materials by adding different fillers, thereby enhancing the chemical and physical stability of the coating itself to meet the stringent requirements of lithium battery cathode current collectors under high voltage. Common fillers are mainly inorganic nanomaterials, and oxide ceramic powder particles and two-dimensional layered materials are often added to the coating as fillers, which is beneficial to improving the corrosion resistance of the cathode current collector under high voltage. In the composite material of this invention, Al2O3 nanoparticles are dispersed on the carrier surface, and the surface of the Al2O3 nanoparticles is coated with graphene oxide. When this composite material is used to prepare a high-voltage corrosion-resistant coating, the Al2O3 dispersed on the carrier surface can form a three-dimensional anti-corrosion barrier inside the coating. Under the synergistic effect of graphene oxide (GO) and Al2O3, the coating will have a shielding effect against corrosive media. Therefore, the coating exhibits excellent corrosion resistance and long life during the high-voltage charging and discharging process of lithium batteries.

[0077] In some embodiments of the present invention, the carrier comprises conductive carbon black.

[0078] It is understandable that conductive carbon black, a type of carbon black material with excellent electrical conductivity, can significantly improve the conductivity of the current collector coating by adding an appropriate amount of conductive carbon black. This allows current to be transferred more effectively from the electrode current collector to the electrochemically active material. Furthermore, in electrochemical energy storage and conversion devices (such as lithium-ion batteries and fuel cells), the catalyst on the electrode is a key factor in promoting electrochemical reactions. As a component of the current collector coating, conductive carbon black can act as a carrier, increasing surface area and improving reaction efficiency, thereby increasing energy conversion efficiency. Moreover, in batteries, the current collector coating is used to collect current and transfer it to the entire electrode surface. The addition of conductive carbon black helps achieve a uniform current distribution, avoiding current concentration in localized areas and reducing losses and safety risks caused by uneven current distribution. Finally, especially during charge-discharge cycles, the current collector may be subject to mechanical stress. The addition of conductive carbon black can also increase the mechanical strength and stability of the current collector coating, which is crucial for the long-term stable operation of electrochemical devices.

[0079] In some other embodiments of the present invention, the present invention provides a method for preparing a composite material, comprising the following steps: dispersing dopamine hydrochloride-modified graphene oxide in a solvent, adding silane coupling agent-modified Al2O3 / carrier composite material, stirring, and then washing and drying the product to obtain the composite material of the present invention.

[0080] It should be noted that the preparation method of the present invention does not require expensive equipment and complex process control, the reaction conditions are not harsh, the raw materials are readily available, the production cost is low, and it is easy to industrialize.

[0081] Specifically, graphene oxide (GO) is modified with dopamine hydrochloride to obtain dopamine hydrochloride-modified graphene oxide (DA-GO). Using conductive carbon black as a carrier, Al2O3 particles are grown in situ on its surface to obtain powder dispersed on the carrier surface (denoted as Al2O3@S). Then, a silane coupling agent is used to graft and modify the surface of the Al2O3@S powder to obtain a silane coupling agent-modified Al2O3 / carrier composite material (denoted as K-Al2O3@S). DA-GO and K-Al2O3@S are electrostatically attracted to each other and assembled into the composite material of this invention (denoted as DA-GO / K-Al2O3@S), a powder filler.

[0082] Therefore, the preparation method of the present invention achieves dispersion and compatibility of GO and Al2O3.

[0083] In some embodiments of the present invention, the preparation method of dopamine hydrochloride modified graphene oxide includes the following steps: adding dopamine hydrochloride to a graphene oxide dispersion, stirring, and then washing and drying the product to obtain the product.

[0084] In some embodiments of the present invention, the preparation method of dopamine hydrochloride modified graphene oxide includes the following steps:

[0085] Add 1.2-1.5g of tris(hydroxymethyl)aminomethane (Tris) to 800-1000mL of deionized water and titrate the solution with dilute hydrochloric acid to set the pH to 8.5;

[0086] Adding 0.1-0.2g of GO to the buffer solution and sonicating for 40-60 minutes will clearly show that the GO has been completely and uniformly dispersed.

[0087] Add 0.1-0.2g of powdered dopamine hydrochloride to the GO dispersion, and stir the mixture at 30-60℃ and 1000-2000r / min for 12-24 hours. The solution will change from brownish-yellow to black.

[0088] The solution was centrifuged at 3000-4500 rpm, then washed three times with ethanol and deionized water, and the resulting product was vacuum dried to obtain the DA-GO composite material.

[0089] In some embodiments of the present invention, the preparation method of the silane coupling agent modified Al2O3 / carrier composite material includes the following steps:

[0090] (1) After dispersing Al(NO3)3·9(H2O) and surfactant in a solvent, add support and Li2CO3, react and calcine to obtain Al2O3 / support composite material;

[0091] (2) The Al2O3 / carrier composite material was grafted with a silane coupling agent to obtain the silane coupling agent modified Al2O3 / carrier composite material.

[0092] In some embodiments of the present invention, the surfactant includes sodium dodecylbenzenesulfonate.

[0093] In some embodiments of the present invention, the calcination temperature is 400°C to 700°C.

[0094] In some embodiments of the present invention, the preparation method of the silane coupling agent modified Al2O3 / carrier composite material includes the following steps:

[0095] (1) Weigh 0.6-0.8g of aluminum nitrate nonahydrate Al(NO3)3·9(H2O), 0.2-0.3g of lithium carbonate (Li2CO3), 0.3-0.4g of sodium dodecylbenzenesulfonate, and then weigh 1.2-1.5g of conductive carbon black (SuperP) material;

[0096] Dissolve aluminum nitrate nonahydrate and sodium dodecylbenzenesulfonate in deionized water, then sonicate for 2-10 minutes. Add conductive carbon black (SuperP) material to the solution and continue sonicating for another 2-10 minutes.

[0097] Then transfer the above mixture to a mixer and stir rapidly for 0.5-1 hour, and add lithium carbonate solution dropwise at a rate of 1.5 seconds per drop.

[0098] After the dripping is complete, stir for 1 hour, then filter and dry, and then calcine at a certain temperature (400℃-700℃) for a certain time to obtain Al2O3@S composite material;

[0099] (2) Dry the Al2O3@S composite material at 90-120℃ for 2-4 hours;

[0100] Weigh 1.2-1.5g of Al2O3@S composite material into a beaker, pour in 75% anhydrous ethanol solution, and add an appropriate amount of acetic acid to adjust the pH of the solution to 5-7.

[0101] Add 0.24-0.3g of silane coupling agent (KH550) and sonicate for about 1-2 hours;

[0102] Then, use a high-speed mixer to stir at 50-80℃ for 4-6 hours at a stirring speed of 500-1000 r / min.

[0103] After the reaction was complete, the reactants were removed, centrifuged, washed, and then dried in a vacuum oven for 12-24 hours to obtain the K-Al2O3@S composite material.

[0104] In some embodiments of the present invention, the method for preparing the composite material is as follows:

[0105] Add the DA-GO composite material to 100 mL of deionized water, and then add 1.2-1.5 g of K-Al2O3@S to the mixture;

[0106] Magnetic stirring 24;

[0107] The mixture was centrifuged, filtered, washed, and vacuum dried to obtain the DA-GO / K-Al2O3@S composite material.

[0108] In other embodiments of the present invention, a high-pressure corrosion-resistant coating for a current collector is provided, the components of which include the composite material of the present invention.

[0109] It is understood that the high-pressure corrosion-resistant coating for current collectors of the present invention uses the composite material of the present invention as a filler, wherein Al2O3 nanoparticles are dispersed on the surface of the carrier, and the surface of the Al2O3 nanoparticles is coated with graphene oxide. When the composite material is used to prepare the high-pressure corrosion-resistant coating, the Al2O3 dispersed on the surface of the carrier can form a three-dimensional anti-corrosion barrier inside the coating. Under the synergistic effect of graphene oxide (GO) and Al2O3, the coating will have the effect of shielding corrosion from corrosive media. Thus, the coating exhibits excellent corrosion resistance and long life during the high-voltage charging and discharging process of lithium batteries.

[0110] In some embodiments of the present invention, the components of the high-pressure corrosion-resistant coating for the current collector also include conductive agents and binders.

[0111] Specifically, DA-GO / K-Al2O3@S, combined with conductive agents, binders, and solvents, can be coated onto the positive electrode current collector to form a protective high-voltage corrosion-resistant coating. DA-GO / K-Al2O3@S can form a three-dimensional corrosion barrier within the coating. Through the synergistic effect of GO and Al2O3, this coating provides a barrier against corrosive media. Benefiting from these advantages, the coating exhibits excellent corrosion resistance and long lifespan during the high-voltage charging and discharging process of lithium batteries.

[0112] In some embodiments of the present invention, the thickness of the high-pressure corrosion-resistant coating on the current collector is 5 μm to 10 μm.

[0113] In some embodiments of the present invention, the positive current collector is an aluminum foil current collector.

[0114] In some embodiments of the present invention, the method for preparing the high-pressure corrosion-resistant coating for the current collector is as follows:

[0115] A slurry is prepared by mixing 1.2-1.5g of DA-GO / K-Al2O3@S powder, 0.15-0.2g of polyvinylidene fluoride (PVDF), 0.15-0.2g of conductive carbon black (SuperP), and 3-5mL of methylpyrrolidone (NMP). This slurry is then coated onto the surface of the positive electrode current collector aluminum foil, vacuum dried, and rolled to form a high-pressure corrosion-resistant coating with a thickness of 10-15μm on the aluminum foil surface.

[0116] The above process can produce a high-pressure corrosion-resistant coating in the positive electrode current collector, which has excellent corrosion resistance.

[0117] In other embodiments of the present invention, a battery positive electrode is provided, comprising the current collector high-pressure corrosion-resistant coating of the present invention.

[0118] It is understood that the positive electrode of the battery of the present invention, because it contains the high-pressure corrosion-resistant coating of the current collector of the present invention, thus possesses at least all the technical effects of the high-pressure corrosion-resistant coating of the current collector, specifically:

[0119] The positive electrode of the battery of the present invention has a high-pressure corrosion-resistant coating on its current collector, which uses the composite material of the present invention as a filler. Al2O3 nanoparticles are dispersed on the surface of the carrier, and the surface of the Al2O3 nanoparticles is coated with graphene oxide. When the composite material is used to prepare the high-pressure corrosion-resistant coating, the Al2O3 dispersed on the surface of the carrier can form a three-dimensional anti-corrosion barrier inside the coating. Under the synergistic effect of graphene oxide (GO) and Al2O3, the coating will have the effect of shielding corrosion from corrosive media. As a result, the lithium battery using the positive electrode of the present invention exhibits excellent corrosion resistance and long life during high-voltage charging and discharging.

[0120] In other embodiments of the present invention, the present invention provides a lithium-ion battery, including the current collector high-pressure corrosion-resistant coating of the present invention or the battery positive electrode of the present invention.

[0121] The lithium-ion battery of the present invention, by containing the current collector high-voltage corrosion-resistant coating or the battery positive electrode of the present invention, thereby possesses at least all the technical effects of the current collector high-voltage corrosion-resistant coating or the battery positive electrode, specifically:

[0122] The lithium-ion battery of the present invention uses the composite material of the present invention as a filler for the high-pressure corrosion-resistant coating of the current collector on the positive electrode. Al2O3 nanoparticles are dispersed on the surface of the carrier, and the surface of the Al2O3 nanoparticles is coated with graphene oxide. When the composite material is used to prepare the high-pressure corrosion-resistant coating, the Al2O3 dispersed on the surface of the carrier can form a three-dimensional anti-corrosion barrier inside the coating. Under the synergistic effect of graphene oxide (GO) and Al2O3, the coating will have the effect of shielding corrosion from corrosive media. Therefore, the lithium battery of the present invention exhibits excellent corrosion resistance and long life during high-voltage charging and discharging.

[0123] The technical solution of the present invention will be better understood below with reference to specific embodiments.

[0124] Example 1

[0125] Weigh out 0.6g of aluminum nitrate nonahydrate Al(NO3)3·9(H2O), 0.2g of lithium carbonate (Li2CO3), 0.3g of sodium dodecylbenzenesulfonate, and then weigh out 1.2g of conductive carbon black (SuperP) material.

[0126] Dissolve aluminum nitrate nonahydrate and sodium dodecylbenzenesulfonate in deionized water, then sonicate for 2 minutes. Add conductive carbon black (SuperP) material to the solution and continue sonicating for another 2 minutes.

[0127] The mixture was then transferred to a mixer and stirred rapidly for 0.5 hours. Lithium carbonate solution was then added dropwise at a rate of 1.5 seconds per drop.

[0128] After the dripping is complete, stir for 1 hour, then filter, dry, and calcine at a certain temperature (400℃) for a certain time to obtain the Al2O3@S composite material. Figure 1 As shown, Al2O3 particles can be seen growing in situ on the surface of conductive carbon black.

[0129] K-Al2O3@S was obtained by grafting Al2O3@S with silane coupling agent (KH550) to obtain (K-Al2O3@S) powder, and the Al2O3@S composite material was dried at 90℃ for 2h.

[0130] Weigh 1.2g of Al2O3@S composite material and place it in a beaker. Pour in 75% anhydrous ethanol solution and add an appropriate amount of acetic acid to adjust the pH of the solution to 5.

[0131] Add 0.24g of silane coupling agent (KH550) and sonicate for about 1 hour;

[0132] The mixture was then stirred at 50°C for 4 hours using a high-speed mixer at a stirring speed of 500 r / min. After the reaction was completed, the reactants were removed, centrifuged, washed, and then dried in a vacuum oven for 12 hours. This yielded the K-Al2O3@S composite material.

[0133] Add 1.2g of tris(hydroxymethyl)aminomethane (Tris) to 800mL of deionized water and titrate the solution with dilute hydrochloric acid to set the pH to 8.5.

[0134] Adding 0.1g of GO to the buffer solution and sonicating for 40 minutes, it can be clearly observed that the GO has been completely and uniformly dispersed.

[0135] 0.1 g of powdered dopamine hydrochloride was added to the GO dispersion, and the mixture was stirred at 30 °C and 1000 r / min for 12 h. The solution changed from brownish-yellow to black.

[0136] The solution was centrifuged at 3000 rpm, then washed three times with ethanol and deionized water, and the resulting product was vacuum dried to obtain the DA-GO composite material.

[0137] Add 100 mL of deionized water solution, and then add 1.2 g of K-Al2O3@S to the mixture.

[0138] Stir magnetically for 24 hours.

[0139] The mixture was centrifuged, filtered, washed, and vacuum dried to obtain the DA-GO / K-Al2O3@S composite material. For example... Figure 2 As shown, DA-GO can be observed to coat the surface of Al2O3 particles.

[0140] A slurry was prepared by mixing 1.2g of DA-GO / K-Al2O3@S powder, 0.15g of polyvinylidene fluoride (PVDF), 0.15g of conductive carbon black (SuperP), and 3mL of methylpyrrolidone (NMP). The slurry was coated onto the surface of the positive electrode current collector aluminum foil, dried under vacuum, and then rolled to form a 10μm thick high-pressure corrosion-resistant coating on the aluminum foil surface.

[0141] The above process can produce a high-pressure corrosion-resistant coating on the positive electrode current collector (aluminum foil), which has excellent corrosion resistance.

[0142] Figure 3 The constant current polarization curves are shown for the positive current collector (aluminum foil) surface with a high-pressure corrosion-resistant coating and the positive current collector (aluminum foil).

[0143] A coin cell is constructed using aluminum foil with a high-voltage corrosion-resistant coating as the working electrode, lithium foil as the counter electrode and reference electrode, commercial ternary high-voltage electrolyte (lithium salt LiPF6), Celgard 2500 separator, and CR2025 battery case. The battery operates at a constant current polarization of 20 μA / cm. 2 The current density was tested. The voltage of the positive current collector (aluminum foil) with a high-voltage corrosion-resistant coating on its surface remained relatively stable at 4V vs. Li / Li over time. + As time goes on, the aluminum foil electrode becomes increasingly polarized, with a polarization voltage as high as 10V.

[0144] Figure 4 The image shows the constant potential polarization curves of the positive current collector (aluminum foil) with a high-voltage corrosion-resistant coating.

[0145] A coin cell was constructed using an aluminum foil current collector with a high-voltage corrosion-resistant coating as the working electrode, a lithium foil as the counter electrode and reference electrode, a commercially available ternary high-voltage electrolyte (lithium salt LiPF6), a Celgard 2500 separator, and a CR2025 battery case. Testing was conducted with constant potential polarization: 6V vs. Li / Li+. The current density of the high-voltage corrosion-resistant coating current collector (aluminum foil) initially reached 10284 μA / cm². 2 Then at 600 s, it was 1509.35 μA / cm. 2 It eventually decreased slowly to 573.95 μA / cm 2 .

[0146] Example 2

[0147] Weigh out 0.8g of aluminum nitrate nonahydrate Al(NO3)3·9(H2O), 0.3g of lithium carbonate (Li2CO3), 0.4g of sodium dodecylbenzenesulfonate, and then weigh out 1.5g of conductive carbon black (SuperP) material.

[0148] Aluminum nitrate nonahydrate and sodium dodecylbenzenesulfonate were dissolved in deionized water and then sonicated for 10 minutes. Conductive carbon black (SuperP) material was added to the solution and sonicated for another 10 minutes.

[0149] The mixture was then transferred to a mixer and stirred rapidly for 1 hour. Lithium carbonate solution was added dropwise at a rate of 1.5 seconds per drop.

[0150] After the dripping is complete, stir for 1 hour, then filter and dry, and then calcine at a certain temperature (700℃) for a certain time to obtain Al2O3@S composite material.

[0151] K-Al2O3@S was obtained by grafting Al2O3@S with silane coupling agent (KH550) to obtain (K-Al2O3@S) powder. The Al2O3@S composite material was dried at 120℃ for 4h.

[0152] Weigh 1.5g of Al2O3@S composite material and place it in a beaker. Pour in 75% anhydrous ethanol solution and add an appropriate amount of acetic acid to adjust the pH of the solution to 7.

[0153] Add 0.3g of silane coupling agent (KH550) and sonicate for about 2 hours;

[0154] The mixture was then stirred at 80°C for 6 hours using a high-speed mixer at a stirring speed of 1000 r / min. After the reaction was completed, the reactants were removed, centrifuged, washed, and then dried in a vacuum oven for 24 hours. This yielded the K-Al2O3@S composite material.

[0155] Add 1.5g of tris(hydroxymethyl)aminomethane (Tris) to 1000mL of deionized water and titrate the solution with dilute hydrochloric acid to set the pH to 8.5.

[0156] Adding 0.2g of GO to the buffer solution and sonicating for 60 minutes, it can be clearly observed that the GO has been completely and uniformly dispersed.

[0157] Add 0.2g of powdered dopamine hydrochloride to the GO dispersion, and stir the mixture at 60℃ and 2000r / min for 24h. The solution changes from brownish-yellow to black.

[0158] The solution was centrifuged at 4500 rpm, then washed three times with ethanol and deionized water, and the resulting product was vacuum dried to obtain the DA-GO composite material.

[0159] Add 100 mL of deionized water solution, and then add 1.5 g of K-Al2O3@S to the mixture.

[0160] Stir magnetically for 24 hours.

[0161] The mixture was centrifuged, filtered, washed, and vacuum dried to obtain the DA-GO / K-Al2O3@S composite material. 1.5g of DA-GO / K-Al2O3@S powder, 0.2g of polyvinylidene fluoride (PVDF), 0.2g of conductive carbon black (SuperP), and 5mL of methylpyrrolidone (NMP) were mixed to form a slurry. This slurry was coated onto the surface of the positive electrode current collector aluminum foil, vacuum dried, and then rolled to form a 15μm thick high-pressure corrosion-resistant coating on the aluminum foil surface.

[0162] The above process can produce a high-pressure corrosion-resistant coating on the positive electrode current collector (aluminum foil), which has excellent corrosion resistance.

[0163] Figure 5 The first three cycles of CV testing were performed on the positive electrode current collector (aluminum foil) with a high-voltage corrosion-resistant coating. The coin cell with the positive electrode current collector (aluminum foil) having a high-voltage corrosion-resistant coating was tested at a voltage range of 2-6V. It was observed that the oxidation potential increased to 4.5V. With each additional CV test cycle, the oxidation current decreased, indicating that the passivation layer tended to stabilize.

[0164] Figure 6 The impedance spectra of the positive electrode current collector (aluminum foil) with and without a high-pressure corrosion-resistant coating are compared. The positive electrode current collector (aluminum foil) with a high-pressure corrosion-resistant coating shows a smaller change in impedance before and after the CV test, indicating that the coating has a stable corrosion-resistant structure.

[0165] Example 3

[0166] Weigh out 0.7g of aluminum nitrate nonahydrate Al(NO3)3·9(H2O), 0.25g of lithium carbonate (Li2CO3), 0.35g of sodium dodecylbenzenesulfonate, and then weigh out 1.35g of conductive carbon black (SuperP) material.

[0167] Dissolve aluminum nitrate nonahydrate and sodium dodecylbenzenesulfonate in deionized water, then sonicate for 5 minutes. Add conductive carbon black (SuperP) material to the solution and continue sonicating for another 5 minutes.

[0168] The mixture was then transferred to a mixer and stirred rapidly for 40 minutes. Lithium carbonate solution was added dropwise at a rate of 1.5 drops per second. After the addition was complete, the mixture was stirred for 1 hour, then filtered, dried, and calcined at a specific temperature (500℃) for a specified time to obtain the Al2O3@S composite material.

[0169] K-Al2O3@S was obtained by grafting Al2O3@S with silane coupling agent (KH550) to obtain (K-Al2O3@S) powder, and the Al2O3@S composite material was dried at 100℃ for 3h.

[0170] Weigh 1.35g of Al2O3@S composite material and place it in a beaker. Pour in 75% anhydrous ethanol solution and add an appropriate amount of acetic acid to adjust the pH of the solution to 6.

[0171] Add 0.25g of silane coupling agent (KH550) and sonicate for about 1-2 hours;

[0172] The mixture was then stirred at 60°C for 5 hours using a high-speed mixer at a stirring speed of 800 r / min. After the reaction was completed, the reactants were removed, centrifuged, washed, and then dried in a vacuum oven for 18 hours. This yielded the K-Al2O3@S composite material.

[0173] Add 1.35g of tris(hydroxymethyl)aminomethane (Tris) to 900mL of deionized water and titrate the solution with dilute hydrochloric acid to set the pH to 8.5.

[0174] Adding 0.15g of GO to the buffer solution and sonicating for 50 minutes, it can be clearly observed that the GO has been completely and uniformly dispersed.

[0175] Add 0.15g of powdered dopamine hydrochloride to the GO dispersion, and stir the mixture at 40℃ and 1500r / min for 18h. The solution changes from brownish-yellow to black.

[0176] The solution was centrifuged at 4000 rpm, then washed three times with ethanol and deionized water, and the resulting product was vacuum dried to obtain the DA-GO composite material.

[0177] Add 100 mL of deionized water solution, and then add 1.35 g of K-Al2O3@S to the mixture.

[0178] Stir magnetically for 24 hours.

[0179] The mixture was centrifuged, filtered, washed, and vacuum dried to obtain the DA-GO / K-Al2O3@S composite material. 1.35g of DA-GO / K-Al2O3@S powder, 0.175g of polyvinylidene fluoride (PVDF), 0.175g of conductive carbon black (SuperP), and 4mL of methylpyrrolidone (NMP) were mixed to form a slurry. This slurry was coated onto the surface of the positive electrode current collector aluminum foil, vacuum dried, and then rolled to form a 12μm thick high-pressure corrosion-resistant coating on the aluminum foil surface.

[0180] The above process can produce a high-pressure corrosion-resistant coating on the positive electrode current collector (aluminum foil), which has excellent corrosion resistance.

[0181] Figure 7 A coin cell battery was constructed using a positive electrode current collector (aluminum foil) with a high-voltage corrosion-resistant coating, subjected to 100 constant-current charge-discharge cycles. The positive electrode active material was ternary NCM (111), the negative electrode was lithium foil, and a commercially available ternary high-voltage electrolyte (lithium salt LiPF6) was used. The separator was Celgard 2500, and the battery casing was CR2025. The coin cell battery with the high-voltage corrosion-resistant coating on the positive electrode current collector (aluminum foil) underwent 100 constant-current charge-discharge cycles within a charge-discharge range of 2.5-4.5V, exhibiting minimal capacity decay.

[0182] This invention utilizes a solution method to grow aluminum oxide particles (Al2O3) in situ on the surface of conductive carbon black using lithium carbonate (Li2CO3), sodium dodecylbenzenesulfonate, and Al(NO3)3·9H2O as raw materials. The preparation method is low-cost and simple.

[0183] Grafting Al2O3@S powder onto the surface using a silane coupling agent effectively disperses the powder, preventing agglomeration. The process is simple and environmentally friendly.

[0184] The assembly of DA-GO and K-Al2O3@S can be achieved simply and conveniently using electrostatic self-assembly.

[0185] Based on the properties of Al2O3, it is incorporated into high-pressure corrosion-resistant coatings. On one hand, Al2O3 itself is beneficial for isolating corrosive media; on the other hand, as a filler in the high-pressure corrosion-resistant coating, during high-voltage charging and discharging, the lithium battery electrolyte solution passivates the Al2O3, forming AlF3, which provides a secondary shielding effect on the electrolyte. This effectively blocks corrosive media. The process is simple to operate, low in cost, and environmentally friendly, making it feasible for widespread application.

[0186] DA-GO / K-Al2O3@S achieves GO coating of Al2O3. On one hand, graphene oxide possesses a large specific surface area. Placing graphene oxide within a high-pressure corrosion-resistant coating acts as a physical shield, extending the erosion path of corrosive media and achieving corrosion protection. It provides a physical protective barrier for corrosion resistance. On the other hand, GO has excellent electrical conductivity, ensuring the conductivity of the high-pressure corrosion-resistant coating.

[0187] A high-voltage corrosion-resistant coating for the positive electrode current collector was prepared using DA-GO / K-Al2O3@S as filler. This coating achieves a three-dimensional, continuous anti-corrosion spatial network formed by GO and Al2O3 within the coating structure. Through the synergistic effect of GO and Al2O3, the coating provides a shielding and corrosion-mitigating effect against commercial electrolytes. As corrosion progresses, GO exerts its shielding effect, while Al2O3, passivated by the commercial electrolyte, provides a secondary shielding effect, thus improving corrosion resistance.

[0188] This invention utilizes a simple solution method, electrostatic self-assembly method, and coating method to prepare a high-pressure corrosion-resistant coating for lithium battery cathode current collectors. Based on the lithium battery cathode preparation process, this invention effectively achieves the preparation of a low-cost, green, and highly corrosion-resistant high-pressure corrosion-resistant coating.

[0189] The present invention has been described in detail above with reference to the embodiments. However, the present invention is not limited to the above embodiments. Within the scope of knowledge possessed by those skilled in the art, various changes can be made without departing from the spirit of the present invention.

Claims

1. A high-pressure corrosion-resistant coating for a current collector, characterized in that, The components include a composite material, which includes a carrier on which Al2O3 nanoparticles are dispersed on the surface, and the surface of the Al2O3 nanoparticles is coated with graphene oxide. The carrier includes conductive carbon black.

2. The high-pressure corrosion-resistant coating for current collectors according to claim 1, characterized in that, The preparation method of the composite material includes the following steps: after dispersing dopamine hydrochloride-modified graphene oxide in a solvent, adding silane coupling agent-modified Al2O3 / carrier composite material, stirring, and then washing and drying the product to obtain the composite material.

3. The high-pressure corrosion-resistant coating for the current collector according to claim 2, characterized in that, The preparation method of the dopamine hydrochloride modified graphene oxide includes the following steps: adding dopamine hydrochloride to the graphene oxide dispersion, stirring, and then washing and drying the product to obtain the graphene oxide.

4. The high-pressure corrosion-resistant coating for current collectors according to claim 2, characterized in that, The preparation method of the silane coupling agent modified Al2O3 / carrier composite material includes the following steps: (1) After dispersing Al(NO3)3•9(H2O) and surfactant in a solvent, add the carrier and Li2CO3, react and calcine to obtain Al2O3 / carrier composite material; (2) The Al2O3 / carrier composite material is grafted and modified by adding a silane coupling agent to obtain the silane coupling agent modified Al2O3 / carrier composite material.

5. The high-pressure corrosion-resistant coating for current collectors according to claim 4, characterized in that, The surfactant includes sodium dodecylbenzenesulfonate.

6. The high-pressure corrosion-resistant coating for the current collector according to claim 4, characterized in that, The calcination temperature is 400℃~700℃.

7. A battery positive electrode, characterized in that, The high-pressure corrosion-resistant coating for current collectors includes any one of claims 1 to 6.

8. A lithium-ion battery, characterized in that, It includes the current collector high-pressure corrosion-resistant coating as described in any one of claims 1 to 6 or the battery positive electrode as described in claim 7.

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