Hollow multi-shell artificial solid electrolyte interphase film and preparation method and application thereof

Abstract

This invention relates to the field of functional materials technology, specifically to a hollow multi-shell artificial solid electrolyte interface (SEI) membrane, its preparation method, and its applications. The method includes the following steps: 1) heating an aqueous solution of a carbon source to obtain a carbon sphere template; 2) dispersing the carbon sphere template obtained in step 1) in a metal salt precursor solution, followed by filtration, washing, and calcination to prepare a metal oxide hollow multi-shell layer; 3) reducing the metal oxide obtained in step 2) to elemental metal, and then placing it in a constant temperature and humidity environment to oxidize its surface, obtaining a metal-metal oxide composite hollow multi-shell layer; 4) coating the metal-metal oxide composite hollow multi-shell layer obtained in step 3) onto a metal foil electrode using a spin-coating method, with auxiliary heating or air blowing during spin-coating to obtain the artificial SEI membrane. This artificial SEI membrane combines strong local mechanical properties with overall flexibility, effectively suppressing lithium dendrite growth in lithium batteries and improving the coulombic efficiency and cycle life of the battery.

Description

Technical Field

[0001] This invention belongs to the field of functional materials technology. Specifically, this invention relates to a hollow multi-shell artificial solid electrolyte interface membrane, its preparation method, and its application. Background Technology

[0002] The energy and environmental crisis is a prominent global challenge. The development and utilization of new energy sources such as solar, wind, and tidal energy hold promise for solving or mitigating this crisis. However, the inherent randomness and volatility of these new energy sources limit their large-scale application. Energy storage technologies, represented by rechargeable batteries, are key supporting technologies for the large-scale application of new energy sources. Although lithium-ion batteries are already widely used in many fields, their energy density is approaching the theoretical value of existing electrode materials, making it difficult to meet current demands.

[0003] Lithium metal, as the anode material for lithium-ion batteries, boasts the highest theoretical energy density (3860 mAh / g) and the lowest redox potential (3.04 V vs. SHE), making it one of the most promising anode materials for lithium-ion batteries. However, the high chemical reactivity of lithium metal makes it prone to reacting with organic electrolytes, consuming electrolyte and forming a large amount of solid electrolyte interface (SEI), resulting in short battery cycle life. Furthermore, lithium metal tends to grow dendrites, which can easily puncture the separator, causing internal short circuits and posing serious safety hazards to the battery.

[0004] Currently, various modification methods have been developed to improve the performance of lithium metal batteries, such as constructing a lithium metal deposition framework, adding additives to the electrolyte, or using solid electrolytes. Although these modification methods have improved the performance of lithium metal batteries to some extent, issues such as coulombic efficiency, cycle life, rate performance, and safety are difficult to simultaneously address, and lithium metal batteries have not yet achieved large-scale commercial use. Summary of the Invention

[0005] The purpose of this invention is to provide a hollow multi-shell artificial solid electrolyte interface (SEI) membrane, its preparation method and application, that is, to provide a new artificial SEI membrane to solve problems such as lithium dendrite growth in lithium metal batteries, so as to improve the performance of lithium metal batteries.

[0006] This invention addresses the problem of lithium dendrite growth in lithium metal batteries by constructing an inorganic-organic composite artificial SEI film. This SEI film is composed of an inorganic hollow multi-shell structure and an organic binder. The metal-metal oxide composite hollow multi-shell structure exhibits good chemical and electrochemical stability, and the surface metal oxide facilitates bonding with the functional groups in the binder. Together, these elements endow the artificial SEI film with strong mechanical stability against lithium dendrite penetration and overall flexibility to resist bending, allowing it to float on water like a lotus leaf, resting on top of lithium metal and remaining stable. Furthermore, to meet the fast-charging performance requirements of lithium metal batteries, an artificial SEI film based on a hollow multi-shell structure and metal-metal oxide composite structure is designed. The metal provides good electronic conductivity, while the metal oxide conducts lithium ions. Multiple composite hollow multi-shell spheres form a three-dimensional mass transfer channel, effectively reducing local current density and improving battery fast-charging performance.

[0007] To achieve the above objectives, the present invention adopts the following technical solution:

[0008] In a first aspect, the present invention provides a method for preparing a hollow multi-shell artificial SEI membrane material. This method includes the following steps:

[0009] 1) Preparation of carbon sphere template: The aqueous solution of carbon source is placed in a reaction vessel and heated to obtain colloidal carbon spheres of micro-nano size. After filtration, washing and drying, carbon sphere template is obtained.

[0010] 2) Preparation of hollow multi-shell metal oxide: The carbon ball template obtained in step 1) is dispersed in a metal ion solution. The resulting suspension is stirred, kept warm and adsorbed, and then processed by filtration, washing, drying and calcination to obtain a hollow multi-shell metal oxide.

[0011] 3) Reduce the metal oxide hollow multi-shell layer obtained in step 2) to a metal hollow multi-shell layer. Then, place the solid in a constant temperature and humidity environment for a certain period of time to allow the solid surface to oxidize, resulting in a metal-metal oxide composite hollow multi-shell layer. The thickness of the metal oxide on the shell surface and the ratio of metal to metal oxide can be controlled by adjusting the temperature, humidity, and time during the constant temperature and humidity environment.

[0012] 4) Add binder and dispersant solvent to the composite hollow multi-shell layer in step 3) and grind into a slurry. Spin coat the slurry onto the electrode surface using a spin coater. After drying, an electrode with an artificial SEI film is obtained. By using auxiliary heating and air blowing during the spin coating process, the slurry is uniformly coated onto the metal foil surface. The thickness of the artificial SEI film is controlled by adjusting the spin speed, slurry viscosity, ambient temperature, and ambient humidity.

[0013] The preparation method of this invention utilizes a controlled surface oxidation process for hollow metal shells to prepare metal-metal oxide composite hollow multi-shell materials. Furthermore, by designing a spin-coating method, coupled with heating and blowing treatment strategies, a hollow multi-shell artificial SEI film is prepared. This preparation method is mild, simple to operate, suitable for large-scale production, and allows for controllable structural parameters and film thickness. The prepared artificial SEI film, when used in energy storage batteries, exhibits high ion permeability, uniform ion flow, and suppression of lithium dendrite formation, significantly improving battery life and performance.

[0014] According to the preparation method of the present invention, it may also have the following additional technical features:

[0015] The carbon source in step 1) includes one or more of glucose, fructose, sucrose, maltose, starch, and citric acid. The concentration of the aqueous solution of the carbon source is 0.1-5M, and the hydrothermal reaction temperature is 160-220℃.

[0016] The metal oxide in step 2) includes one or more of copper oxide, cobalt oxide, nickel oxide, iron oxide, manganese oxide, and titanium oxide.

[0017] In step 3), the reducing agent is sodium borohydride, potassium borohydride, sodium bisulfite, ammonia, hydrogen, or carbon monoxide, and the reduction temperature is 25-500℃.

[0018] In step 3), the metal element hollow multi-shell layer is placed in a constant temperature and humidity environment at a temperature of 25-100℃ and a humidity of 10-60% for 8-24 hours; the metal-metal oxide composite hollow multi-shell layer is one or more of the following: copper-cuprous oxide, copper-copper oxide, cobalt-cobalt oxide, iron-iron tetroxide, nickel-nickel oxide, manganese-manganese oxide, titanium-titanium oxide, etc.

[0019] In step 4), the binder includes one or a combination of two of polyvinylidene fluoride, polyethylene, polypropylene, and ethyl cellulose; the dispersant includes one or a combination of two or more of ethanol, acetone, terpineol, pyridine, tetrahydrofuran, and ethylene glycol methyl ether; the mass ratio of hollow multi-shell, binder, and dispersant is 1:(0.01-5):(1-10), and the grinding time is 0.5-1h.

[0020] In step 4), during spin coating, the spin coater speed is 1000-9000 r / min; the spin coating time is 10-60 s; and the spin coating slurry dosage is 0.1-1 mL / cm³. 2 The number of spin coating cycles is 1-3; the spin coating heating temperature is 25-80℃, and the air blowing speed is 10-25m / s; the metal foil can be copper foil, nickel foil, titanium foil, stainless steel foil, etc.

[0021] A second aspect of the present invention provides a hollow multi-shell artificial SEI membrane material.

[0022] The hollow multi-shell artificial SEI membrane material is prepared by the method described in the first aspect. The artificial SEI membrane is a composite membrane of hollow multi-shells and an adhesive, with a thickness of 1-30 micrometers. The hollow multi-shells are uniformly distributed inside, and the shell walls of the hollow multi-shells are 1-4 layers.

[0023] The metal-metal oxide composite hollow multi-shell structure features metals with excellent electronic conductivity, while the surface oxides not only facilitate uniform lithium ion transport, reduce local current, and decrease lithium dendrites, but also combine with functional groups in the binder to improve the overall mechanical stability of the artificial SEI film.

[0024] The hollow multi-shell artificial SEI membrane of the present invention, used in lithium metal batteries, significantly improves the coulombic efficiency and cycle life of lithium metal batteries.

[0025] A third aspect of the present invention provides the application of hollow multi-shell artificial SEI film materials as described in the first aspect in the field of lithium batteries.

[0026] This invention provides a lithium metal battery anode, wherein the lithium anode is modified with an artificial SEI film as described in this invention to suppress lithium dendrite growth and reduce local current density, thereby significantly improving the coulombic efficiency, cycle life and safety of the battery.

[0027] Compared with the prior art, the advantages of the present invention are:

[0028] 1) The main material of the artificial SEI membrane described in this invention is a metal-metal oxide composite hollow multi-shell structure material. The metal hollow multi-shell is first obtained through reduction, and then left to stand in a constant temperature and humidity environment for a certain period of time, allowing the surface of the multi-shell to be oxidized. The thickness of the metal oxide on the shell surface and the ratio of metal to metal oxide can be precisely controlled. The internal metal multi-shell can rapidly conduct electrons, reducing local current, while the surface metal oxide can not only guide the uniform distribution of lithium ions during transport, reducing local current and lithium dendrites, but also combine with functional groups in the binder, improving the overall mechanical stability of the artificial SEI membrane.

[0029] 2) A hollow multi-shell layer is coated onto a metal foil using a spin coating method to obtain an artificial SEI film. By employing auxiliary heating and air blowing during the spin coating process, the slurry can be uniformly coated onto the metal foil surface. Furthermore, by controlling factors such as rotation speed, slurry viscosity, ambient temperature, and humidity, the thickness of the artificial SEI film can be precisely controlled. The thickness of the artificial SEI film can be controlled between 1 and 30 micrometers. Preferably, this invention controls the artificial film thickness to 1-2 micrometers. A thin artificial SEI film reduces the mass of inactive materials, which is beneficial for achieving higher battery energy density.

[0030] 3) The artificial SEI film is an organic-inorganic composite film. The inorganic portion has high mechanical strength, which can resist lithium dendrite puncture; the organic portion provides overall flexibility to the SEI film. Using this artificial SEI film as a lithium metal anode can significantly improve battery performance and lifespan. The battery has undergone long-cycle testing, achieving 1 mA / cm². 2 After 500 cycles at the specified current, the coulombic efficiency remains above 99.5%. When the aforementioned anode is combined with NCM811 to form a full cell, the capacity remains above 160 mAh / g after 100 cycles at 1C current. As a lithium metal anode, its performance far surpasses that of nanoparticles or anodes without any loaded material of the same composition. When the aforementioned anode is combined with NCM811 to prepare a pouch cell, it can operate normally for more than 40 cycles, demonstrating its potential for commercial application. Attached Figure Description

[0031] Figure 1 This is a transmission electron microscope image of hollow multi-shell copper oxide from Embodiment 1 of the present invention;

[0032] Figure 2 This is a transmission electron microscope (TEM) image of a copper-cuprous oxide composite hollow multi-shell structure from Example 1 of this invention.

[0033] Figure 3 This is the X-ray diffraction pattern of the hollow multi-shell copper oxide in Embodiment 1 of the present invention;

[0034] Figure 4 This is the X-ray diffraction pattern of the copper-cuprous oxide composite hollow multi-shell structure of Embodiment 1 of the present invention;

[0035] Figure 5 This is a scanning electron microscope image of the cross-section of the electrode with an artificial SEI film mounted on a copper foil substrate according to Embodiment 1 of the present invention.

[0036] Figure 6 The electrode carrying the artificial SEI film in Embodiment 1 of this invention has a 2mAh / cm² capacity. 2 Scanning electron microscope image of the cross-section of lithium metal;

[0037] Figure 7 This is a coulombic efficiency diagram of the battery cycle in Embodiment 1 of the present invention. Detailed Implementation

[0038] The present invention will be further described below with reference to specific embodiments.

[0039] This invention provides a method for preparing a hollow multi-shell artificial SEI membrane, the method comprising:

[0040] (a) A carbon source aqueous solution with a concentration of 0.1-5M is placed in a hydrothermal reactor at 160-220℃ and hydrothermally reacted for 2-3 hours. After cooling, the carbon sphere template is obtained by filtration and drying.

[0041] (b) The carbon sphere template obtained in step a) is dispersed in a metal ion solution. The metal salt is one or more combinations of acetate, chloride, nitrate, and sulfate, and the metal ion concentration is 0.01–3 mol / L. The carbon sphere template adsorbs metal ions, and then, after filtration, washing, drying, and calcination, a hollow multi-shell metal oxide is obtained. The prepared metal oxide includes one or more combinations of copper oxide, cobalt oxide, nickel oxide, iron oxide, manganese oxide, and titanium oxide.

[0042] (c) The hollow multi-shell metal oxide obtained in step b) is reduced to a hollow multi-shell metal element using a reducing agent, wherein the reducing agent is sodium borohydride, potassium borohydride, sodium bisulfite, ammonia, hydrogen, or carbon monoxide. The reduction temperature is 25-500℃, and the reduction time is 30-180 min.

[0043] The metal element hollow multi-shell layer is placed in a constant temperature and humidity environment at a temperature of 25-100℃ and a humidity of 10-60% for 8-24 hours; the metal-metal oxide composite hollow multi-shell layer is one or more of the following: copper-cuprous oxide, copper-copper oxide, cobalt-cobalt oxide, iron-iron tetroxide, nickel-nickel oxide, manganese-manganese oxide, titanium-titanium oxide, etc.

[0044] (d) Add a binder and a dispersing solvent to the metal-metal oxide composite hollow multi-shell layer from step c) and grind it into a slurry. The binder is one or a combination of two of polyvinylidene fluoride, polyethylene, polypropylene, and ethyl cellulose, and the dispersant is one or a combination of two or more of ethanol, acetone, terpineol, pyridine, tetrahydrofuran, and ethylene glycol methyl ether. The mass ratio of the hollow multi-shell layer, binder, and dispersant is 1:(0.01-5):(1-10), and the grinding time is 0.5-1 h.

[0045] The slurry described in step d) is prepared at a concentration of 0.1-1 mL / cm³. 2The coating agent is evenly applied to the electrode substrate, which can be a metal foil surface, such as copper foil, nickel foil, titanium foil, or stainless steel foil. The spin coating speed is 1000-9000 r / min, the spin coating time is 10-60 s, the number of spin coatings is 1-3, the spin coating heating temperature is 25-80℃, and the air blowing speed is 10-25 m / s.

[0046] The spin-coated substrate is dried under vacuum at a temperature of 50-100°C for 8-24 hours to obtain an electrode with an artificial interface film.

[0047] Example 1

[0048] A method for preparing a hollow multi-shell artificial SEI membrane and its application, the method comprising:

[0049] (1) A 1M sucrose aqueous solution was placed in a hydrothermal reactor at 200℃ and hydrothermally reacted for 2 hours. After cooling, carbon sphere templates were obtained by filtration and drying. The drying conditions were: 50℃, 8 hours.

[0050] (2) The carbon sphere template obtained in step (1) is dispersed in a copper acetate solution with a concentration of 0.01 mol / L. The carbon sphere template adsorbs copper ions for 15 h at an adsorption temperature of 25 °C. After filtration, washing, drying, and calcination in a muffle furnace, hollow multi-shell copper oxide spheres with two shells are obtained.

[0051] (3) The copper oxide hollow multi-shell layer described in step (2) is dispersed in a 0.05M sodium borohydride aqueous solution. The reaction takes place at room temperature and lasts for 2 hours. After the reaction is complete, the solid is obtained by filtration, washed three times, and dried at 50°C for 8 hours to obtain the copper hollow multi-shell layer.

[0052] (4) The copper hollow multi-shell layer was placed in a constant temperature and humidity chamber at 25°C with a humidity of 10% and left to stand for 8 hours to obtain a copper-cuprous oxide composite hollow multi-shell layer.

[0053] (5) Hollow multi-shell structure, polyvinylidene fluoride, and terpineol were mixed in a mass ratio of 1:0.05:10 and ground for 0.5 hours to obtain a slurry with suitable viscosity. The slurry was prepared at a viscosity of 0.1 mL / cm³. 2 The coating agent was evenly applied to the copper foil substrate. The spin coating speed was 1000 r / min, and the spin coating time was 10 s. The spin coating was carried out at a temperature of 25℃ and the blowing gas flow rate was 10 m / s. The spin-coated electrode was dried under vacuum at a drying temperature of 100℃ for 8 hours to obtain an electrode coated with an artificial SEI film. The thickness of the artificial SEI film was approximately 2 micrometers.

[0054] (6) Cut the electrode with the artificial SEI film from step (5) into a circular electrode sheet with a diameter of 12 mm to serve as the working electrode of the battery. Use a lithium sheet with a diameter of 14 mm as the counter electrode. Separate the two electrodes with a 19 mm separator. Add 60 μl of electrolyte (solute is 1M lithium bis(trifluoromethanesulfonyl)imide, solvent is dioxolane:ethylene glycol dimethyl ether = 1:1) and assemble into a coin cell. Conduct a long-cycle test on the battery under the conditions of a current of 1 mA and a charge / discharge capacity of 1 mH.

[0055] Transmission electron microscopy images of the hollow multi-shell copper oxide obtained are as follows: Figure 1 As shown, it consists of two hollow spheres. The electron microscope image of the copper hollow multi-shell structure obtained after reduction is shown below. Figure 2 As shown in the figure, the morphology and structure of the hollow spheres did not change significantly after reduction. The X-ray diffraction patterns of the copper oxide hollow spheres and the copper-cuprous oxide hollow multi-shell are shown in the figures below. Figure 3 , Figure 4 As shown. A scanning electron microscope image of the electrode cross-section after spin coating is shown below. Figure 5 As shown, the artificial interface film structure is uniform, with a thickness of 1-2 micrometers. The cross-sectional scanning electron microscope image of the electrode after lithium intercalation is shown below. Figure 6 As shown in the figure, the sandwich structure of substrate-lithium metal-artificial SEI film is illustrated, with the artificial SEI film exhibiting a "lotus leaf" effect on the lithium metal. The battery cycle efficiency is as follows: Figure 7 As shown, with 1mA / cm 2 After 500 cycles of cycling with the current, the battery with the artificial SEI film still maintained a coulombic efficiency of 99.5%. Obviously, its cycle life and coulombic efficiency are better than those of the battery without the artificial SEI film.

[0056] Example 2

[0057] A method for preparing an artificial SEI membrane, the method comprising:

[0058] (1) A 0.1M sucrose aqueous solution was placed in a hydrothermal reactor at 180℃ and hydrothermally reacted for 2 hours. After cooling, carbon sphere templates were obtained by filtration and drying. The drying conditions were: 50℃, 12 hours.

[0059] (2) The carbon sphere template obtained in step (1) is dispersed in ferric nitrate solution with a concentration of 1.0 mol / L. The carbon sphere template adsorbs iron ions for 8 hours at an adsorption temperature of 40℃. After filtration, washing, drying, and calcination in a muffle furnace, hollow multi-shell spheres of iron oxide with 3 shells are obtained.

[0060] (3) The iron oxide hollow multi-shell layer described in step (2) is reduced with carbon monoxide at a reduction temperature of 500°C for a reaction time of 3 hours to obtain the iron hollow multi-shell layer.

[0061] (4) The iron hollow multi-shell layer was placed in a constant temperature and humidity chamber at 60℃ with a humidity of 30% and left to stand for 24 hours to obtain an iron-iron tetroxide composite hollow multi-shell layer.

[0062] (5) The composite hollow multi-shell layer, ethyl cellulose, and terpineol + ethylene glycol methyl ether (1:1) from step (4) are mixed in a mass ratio of 1:1:1 and ground for 1 hour to obtain a slurry with suitable viscosity. The slurry has a viscosity of 0.5 mL / cm³. 2 The slurry was evenly applied to the nickel foil substrate. The nickel foil coated with the slurry was then spin-coated using a spin coater at a speed of 5000 r / min for 30 s. Spin-coating was performed at 25°C with an airflow velocity of 10 m / s. The spin-coated electrode was then dried under vacuum at 80°C for 12 hours to obtain an electrode coated with an artificial SEI film, the thickness of which was approximately 6 micrometers.

[0063] Example 3

[0064] A method for preparing an artificial SEI membrane, the method comprising:

[0065] (1) A 5M glucose aqueous solution was placed in a hydrothermal reactor at 200℃ and hydrothermally reacted for 3 hours. After cooling, the carbon ball template was obtained by filtration and drying. The drying conditions were: 70℃, 24 hours.

[0066] (2) The carbon sphere template obtained in step (1) is dispersed in a nickel chloride solution with a nickel chloride concentration of 3.0 mol / L. The carbon sphere template adsorbs nickel ions for 24 h at an adsorption temperature of 40 °C. After filtration, washing, drying, and calcination in a muffle furnace, hollow multi-shell nickel oxide with 4 shells is obtained.

[0067] (3) The nickel oxide hollow multi-shell layer described in step (2) is reduced with hydrogen at a reduction temperature of 500°C for a reaction time of 2 hours to obtain a nickel hollow multi-shell layer.

[0068] (4) The nickel hollow multi-shell layer was placed in a constant temperature and humidity chamber at 100℃ with a humidity of 60% and left to stand for 24 hours to obtain a nickel-nickel oxide composite hollow multi-shell layer.

[0069] (5) The composite hollow multi-shell layer, polypropylene, and tetrahydrofuran from step (3) are mixed in a mass ratio of 1:0.5:5 and ground for 1 hour to obtain a slurry with suitable viscosity. The slurry is prepared at a viscosity of 1 mL / cm³. 2The slurry was evenly applied to the titanium foil substrate. The titanium foil coated with the slurry was then spin-coated using a spin coater at a speed of 9000 r / min for 30 s. Spin-coating was performed at 25°C with an airflow velocity of 25 m / s. The spin-coated electrode was then dried under vacuum at 100°C for 24 hours. The resulting electrode was coated with an artificial SEI film, which was approximately 10 micrometers thick.

[0070] Example 4

[0071] A method for preparing an artificial SEI membrane, the method comprising:

[0072] (1) A 1M sucrose aqueous solution was placed in a hydrothermal reactor at 220℃ and reacted hydrothermally for 2.5h. After cooling, the carbon ball template was obtained by filtration and drying. The drying conditions were 80℃ for 24h.

[0073] (2) The carbon sphere template obtained in step (1) was dispersed in a copper acetate solution with a concentration of 3 mol / L. The carbon sphere template adsorbed copper ions for 24 h at an adsorption temperature of 40 °C. After filtration, washing, drying, and calcination in a muffle furnace, hollow multi-shell copper oxide with 3 shells was obtained.

[0074] (3) The copper oxide hollow multi-shell layer described in step (2) is dispersed in a 1M sodium bisulfite aqueous solution. The reduction reaction occurs at room temperature and lasts for 2 hours. After the reaction is complete, the solid is obtained by filtration, washed three times, and dried at 70°C for 12 hours to obtain the copper hollow multi-shell layer.

[0075] (4) The copper hollow multi-shell layer was placed in a constant temperature and humidity chamber at 100℃ with a humidity of 60% and left to stand for 24 hours to obtain a copper-copper oxide composite hollow multi-shell layer.

[0076] (5) The composite hollow multi-shell layer, polyethylene, and pyridine from step (4) were mixed in a mass ratio of 1:0.2:10 and ground for 1 hour to obtain a slurry with suitable viscosity. The slurry was uniformly applied to a copper foil substrate at a dosage of 0.5 mL / cm². The copper foil coated with the slurry was then spin-coated using a spin coater at a speed of 9000 r / min for 20 seconds. The spin coating was carried out at 40°C with an air blowing speed of 10 m / s. After drying at room temperature, the spin coating process was repeated once. Finally, the spin-coated electrode was dried under vacuum at 100°C for 12 hours to obtain an electrode coated with an artificial SEI film, the thickness of which was approximately 16 micrometers.

[0077] Example 5

[0078] A method for preparing an artificial SEI membrane, the method comprising:

[0079] (1) A 1M sucrose aqueous solution was placed in a hydrothermal reactor at 180℃ and reacted hydrothermally for 2.5h. After cooling, the carbon ball template was obtained by filtration and drying. The drying conditions were: 70℃, 12h.

[0080] (2) The carbon sphere template obtained in step (1) is dispersed in a cobalt acetate solution with a concentration of 1 mol / L. The carbon sphere template adsorbs cobalt ions for 8 hours at an adsorption temperature of 30°C. After filtration, washing, drying, and calcination in a muffle furnace, a hollow multi-shell cobalt tetroxide with 4 shells is obtained.

[0081] (3) The cobalt tetroxide hollow multi-shell layer described in step (2) is reduced with hydrogen at a reduction temperature of 500°C for 3 hours to obtain a cobalt hollow multi-shell layer.

[0082] (4) The cobalt hollow multishell was placed in a constant temperature and humidity chamber at 100℃ with a humidity of 60% and left to stand for 24 hours to obtain a cobalt-cobalt oxide composite hollow multishell.

[0083] (5) The composite hollow multi-shell layer, ethyl cellulose, and acetone from step (3) were mixed in a mass ratio of 1:0.01:5 and ground for 0.5 hours to obtain a slurry with suitable viscosity. The slurry was prepared at a viscosity of 0.1 mL / cm³. 2 The paste was evenly applied to the copper foil substrate. The copper foil coated with the paste was then spin-coated using a spin coater at a speed of 2000 r / min for 20 s. Spin-coating was performed at 60°C with an airflow velocity of 10 m / s. The spin-coated electrode was then dried under vacuum at 90°C for 12 hours, resulting in an electrode coated with an artificial SEI film. The thickness of the artificial SEI film was approximately 1 micrometer.

[0084] Example 6

[0085] A method for preparing an artificial SEI membrane, the method comprising:

[0086] (1) A 1M sucrose aqueous solution was placed in a hydrothermal reactor at 200℃ and reacted hydrothermally for 2.5h. After cooling, the carbon ball template was obtained by filtration and drying. The drying conditions were: 70℃, 10h.

[0087] (2) The carbon sphere template obtained in step (1) is dispersed in a copper acetate solution with a concentration of 0.5 mol / L. The carbon sphere template adsorbs copper ions for 12 h at an adsorption temperature of 60 °C. After filtration, washing, drying, and calcination in a muffle furnace, hollow multi-shell copper oxide with two shells is obtained.

[0088] (3) The copper oxide hollow multi-shell layer described in step (2) is dispersed in a 1M potassium bisulfite aqueous solution. The reaction takes place at room temperature and lasts for 2 hours. After the reaction is complete, the solid is obtained by filtration, washed three times, and dried at 70°C for 12 hours to obtain the copper hollow multi-shell layer.

[0089] (4) The copper hollow multishell was placed in a constant temperature and humidity chamber at 40℃ with a humidity of 20% and left to stand for 10 hours to obtain a copper-cuprous oxide composite hollow multishell.

[0090] (5) The copper-based hollow multi-shell material, ethyl cellulose, and ethanol from step (4) were mixed in a mass ratio of 1:0.1:10 and ground for 1 hour to obtain a slurry with suitable viscosity. The slurry was prepared at a viscosity of 1 mL / cm³. 2 The slurry was evenly applied to the copper foil substrate. The copper foil coated with the slurry was then spin-coated using a spin coater at a speed of 4000 r / min for 60 s. Spin-coating was performed at 40°C with an airflow velocity of 10 m / s. After drying at room temperature, the spin-coating process was repeated once. The spin-coated electrode was then dried under vacuum at 90°C for 12 h to obtain an electrode coated with an artificial SEI film, the thickness of which was approximately 20 micrometers.

[0091] Example 7

[0092] A method for preparing an artificial SEI membrane, the method comprising:

[0093] (1) A 0.2M sucrose aqueous solution was placed in a hydrothermal reactor at 180℃ and hydrothermally reacted for 2.5h. After cooling, carbon sphere templates were obtained by filtration and drying. The drying conditions were: 70℃, 12h.

[0094] (2) The carbon sphere template obtained in step (1) is dispersed in a copper nitrate solution with a copper nitrate concentration of 2 mol / L. The carbon sphere template adsorbs copper ions for 12 h at an adsorption temperature of 35 °C. After filtration, washing, drying, and calcination in a muffle furnace, hollow multi-shell copper oxide with 3 shells is obtained.

[0095] (3) The copper oxide hollow multi-shell layer described in step (2) is dispersed in a 1M potassium borohydride aqueous solution. The reduction reaction occurs at room temperature and lasts for 2 hours. After the reaction is complete, the solid is obtained by filtration, washed three times, and dried at 70°C for 12 hours to obtain the copper hollow multi-shell layer.

[0096] (4) The copper hollow multi-shell layer was placed in a constant temperature and humidity chamber at 50℃ with a humidity of 10% and left to stand for 24 hours to obtain a copper-cuprous oxide composite hollow multi-shell layer.

[0097] (5) The copper-based hollow multi-shell material, ethyl cellulose, and acetone from step (3) were mixed in a mass ratio of 1:0.1:10 and ground for 0.5 hours to obtain a slurry with suitable viscosity. The slurry was uniformly applied to the copper foil substrate at a dosage of 1 mL / cm². The copper foil coated with the slurry was then spin-coated using a spin coater at a speed of 9000 r / min for 10 seconds. The spin coating was carried out at 80°C with an air blowing speed of 25 m / s. After drying, the spin coating process was repeated twice. The spin-coated electrode was dried under vacuum at 90°C for 20 hours to obtain an electrode coated with an artificial SEI film, the thickness of which was approximately 30 micrometers.

[0098] All aspects not described in detail in this invention can be covered using conventional technical knowledge in the field.

[0099] Finally, it should be noted that the above embodiments are only used to illustrate the implementation of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to the embodiments, those skilled in the art should understand that modifications or equivalent substitutions to the technical solutions of the present invention will not depart from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A method for preparing a hollow multi-shell artificial solid electrolyte interface (SEI) film, comprising the following steps: 1) placing a carbon source aqueous solution into a reaction kettle for hydrothermal reaction to obtain micro-nano-sized colloidal carbon spheres, and then performing filtration, washing and drying to obtain a carbon sphere template; 2) dispersing the carbon sphere template obtained in step 1) in a metal salt solution, stirring, incubating and adsorbing the obtained suspension, and then performing filtration, washing, drying and calcination to obtain a metal oxide hollow multi-shell layer; 3) reducing the metal oxide hollow multi-shell layer obtained in step 2) into a metal element hollow multi-shell layer by using a reducing agent, and then placing the solid in a constant temperature and humidity environment for a certain time to oxidize the surface of the solid, thereby obtaining a metal-metal oxide composite hollow multi-shell layer; and 4) mixing the composite hollow multi-shell layer obtained in step 3) with an organic binder, adding a dispersion solvent to grind into a slurry, and then applying a spin coating method, and performing auxiliary heating and air blowing during the spin coating process to uniformly coat the slurry on the surface of a metal foil, and then performing drying to obtain a hollow multi-shell structure-based metal-metal oxide composite artificial SEI film. The carbon source in step 1) comprises one or more than two combinations of glucose, fructose, sucrose, maltose, starch and citric acid, the concentration of the carbon source aqueous solution is 0.1-5 M, and the hydrothermal reaction temperature is 160-220 ℃. The metal oxide in step 2) comprises one or more than two combinations of copper oxide, cobalt oxide, nickel oxide, iron oxide, manganese oxide and titanium oxide. The reducing agent in step 3) is sodium borohydride, potassium borohydride, sodium bisulfite, ammonia, hydrogen or carbon monoxide, and the reduction temperature is 25-500 ℃. The temperature for placing the metal element hollow multi-shell layer in step 3) in the constant temperature and humidity environment is 25-100 ℃, the humidity is 10-60%, and the standing time is 8-24 h. The metal-metal oxide composite hollow multi-shell layer is one or more than two combinations of copper-cuprous oxide, copper-copper oxide, cobalt-cobalt oxide, iron-magnetite, nickel-nickel oxide, manganese-manganese oxide and titanium-titanium oxide. The organic binder in step 4) comprises one or more than two combinations of polyvinylidene fluoride, polyethylene, polypropylene and ethyl cellulose; the dispersion solvent comprises one or more than two combinations of ethanol, acetone, terpineol, pyridine, tetrahydrofuran and ethylene glycol methyl ether; and the mass ratio of the hollow multi-shell layer, the organic binder and the dispersant is 1: (0.01-1) : (1-10), and the grinding time is 0.5-1 h. The hollow multi-shell artificial SEI film is obtained by the preparation method of any one of claims 1-7. The shell wall of the hollow multi-shell layer is 1-4 layers; the thickness of the artificial SEI film is 1-30 microns, and the internal composite hollow multi-shell layer is uniformly distributed; and the artificial SEI film is a composite film of the hollow multi-shell layer and the organic binder. 10.The artificial SEI film of claim 8 or 9 is applied in an energy storage battery. ​ ​ 2. The preparation method according to claim 1, characterized in that, ​ 3. The production method according to claim 1 or 2, characterized by, ​ 4. The production method according to any one of claims 1 to 3, characterized by, ​ 5. The production method according to any one of claims 1 to 4, characterized by, ​ 6. The production method according to any one of claims 1 to 5, characterized by, ​ 7. The production method according to any one of claims 1 to 6, characterized by, In the step 4), the rotation speed of the spin coater is set to 1000-9000 r / min; the spin coating time is 10-60 s; the amount of the spin coating slurry is 0.1-1 mL / cm 2 ; the spin coating times are 1-3 times; the heating temperature of the spin coating is 25-80 °C; the air flow speed is 10-25 m / s; and the metal foil can be selected from copper foil, nickel foil, titanium foil or stainless steel foil.

1. A method for preparing a metal foil, comprising the following steps: 1) preparing a metal foil; 2) preparing a solution of a metal salt; 3) preparing a solution of a reducing agent; 4) coating the metal foil prepared in the step 1) with the solution of the metal salt prepared in the step 2) and the solution of the reducing agent prepared in the step 3) by spin coating; and 5) drying the metal foil coated in the step 4) to obtain a metal foil.

8. A hollow multi-shell artificial SEI membrane, characterized by, ​ 9. The hollow multi-shell artificial SEI membrane according to claim 8, wherein ​ ​

Images