An all-solid-state battery

Abstract

This invention provides an all-solid-state battery, which includes at least one power generation unit. This unit comprises a positive current collector, a positive electrode membrane, a solid electrolyte, a carbon material layer, and a bulk material layer. The bulk material layer has a three-dimensional carbon material framework, providing a rapid channel for the deposition and extraction of metallic lithium on and within the bulk material layer. Lithium and / or lithium alloys in the bulk material provide reserve active lithium for the lithium metal battery, significantly extending its cycle life. The carbon material layer is elastically variable, providing space for newly deposited metallic lithium while effectively improving the interfacial contact between the bulk material layer and the solid electrolyte, reducing contact resistance. By adjusting the quality and type of nucleating agents in the bulk material layer and the carbon material layer, efficient and controllable deposition of metallic lithium is achieved, effectively improving the defects of the metallic lithium anode. This allows the all-solid-state battery to achieve high rate performance while also possessing a longer cycle life and high safety.

Description

Technical Field

[0001] This invention belongs to the field of batteries, and specifically relates to an all-solid-state battery. Background Technology

[0002] For a long time, lithium-ion batteries have been the most widely used electrochemical energy source in fields such as mobile communications and electric vehicles. However, with continuous technological advancements, lithium-ion batteries have reached their energy density limit (250Wh / kg-300Wh / kg), necessitating the development of lithium batteries with higher energy density to meet people's demand for longer battery life in electrical devices. Moreover, long-term use has revealed significant safety hazards associated with lithium-ion batteries due to the use of liquid electrolytes. The limitations in energy density and potential safety risks are forcing people to continuously seek new electrochemical energy storage devices with higher energy density and greater safety.

[0003] To improve battery energy density, researchers have begun using lithium metal, which has a higher specific capacity, as the anode, and have developed lithium metal batteries with even higher energy density. However, these high-energy-density batteries are still in the research stage or applied in some specialized fields, and have not yet entered people's daily lives on a large scale. Ultimately, this is due to the significant safety hazards inherent in lithium metal batteries. The lithium metal anode used in these batteries is prone to lithium dendrite formation. With cycling, these dendrites can easily lead to short circuits, resulting in thermal runaway, battery explosions, and other safety issues. Simply using surface protection or modifying the lithium metal cannot effectively improve the performance of the lithium metal anode or eliminate safety hazards. A comprehensive and meticulous design of the lithium metal anode is needed to enable the large-scale application of lithium metal batteries.

[0004] To improve battery safety, solid-state electrolytes have been used to replace liquid electrolytes. While solid-state electrolytes can improve battery safety and prevent accidents, they are also rigid, resulting in point-to-point hard contact with the positive and negative electrode films. This small interfacial contact area increases the internal resistance at each interface, leading to a decrease in the performance of all-solid-state batteries.

[0005] In conclusion, it is indeed necessary to provide a high-energy-density, high-safety all-solid-state battery. Summary of the Invention

[0006] This invention provides an all-solid-state battery, which includes at least one power generation unit. This unit comprises a positive current collector, a positive electrode membrane, a solid electrolyte, a carbon material layer, and a lithium-containing bulk material layer. The lithium-containing bulk material layer has a three-dimensional carbon material framework, providing a rapid channel for the deposition and extraction of metallic lithium on and within the bulk material layer. The lithium and / or lithium alloys in the bulk material provide reserve active lithium for the lithium metal battery, significantly extending its cycle life. The carbon material layer is elastically variable, providing space for newly deposited metallic lithium while effectively improving the interfacial contact between the bulk material layer and the solid electrolyte, reducing contact resistance. By adjusting the quality and type of nucleating agents in the bulk material layer and the carbon material layer, efficient and controllable deposition of metallic lithium is achieved, effectively improving the defects of the lithium metal anode. This allows the all-solid-state battery to achieve high rate performance while also possessing a longer cycle life and higher safety.

[0007] To achieve the above-mentioned objectives, in some embodiments, the present invention provides an all-solid-state battery, characterized in that the all-solid-state battery includes at least one power generation unit, which includes a positive current collector, a positive electrode membrane, a solid electrolyte, a carbon material layer, and a bulk material layer. The bulk material layer includes lithium and / or a lithium alloy, a carbon material framework, and a nucleating agent. The carbon material layer includes a carbon material framework and a nucleating agent. The carbon material framework and nucleating agent in the bulk material layer and the carbon material layer may be the same or different. The mass a of the nucleating agent in the bulk material layer and the mass b of the nucleating agent in the carbon material layer satisfy: a ≥ b, or the bonding bond energy Ea between the nucleating agent and lithium in the bulk material layer is higher than the bonding bond energy Eb between the nucleating agent and lithium in the carbon material layer.

[0008] In some embodiments, the carbon material framework in the bulk material layer is at least one of a micro / nano carbon material framework or a composite framework of micro / nano carbon materials and metal materials.

[0009] The micro / nano carbon material is at least one of the following: multi-walled carbon nanotubes, few-walled carbon nanotubes, single-walled carbon nanotubes, graphene, ordered mesoporous carbon, whisker carbon nanotubes, graphite, carbon black, and carbon fiber.

[0010] The metal material mentioned is one that does not react with lithium metal at room temperature or exists in a stable compound with lithium metal at room temperature, such as beryllium, chromium, cesium, iron, hafnium, potassium, manganese, molybdenum, sodium, nickel, titanium, vanadium, zirconium, copper, etc.

[0011] In some embodiments, the carbon material skeleton is configured as linear, coiled, net-like, spherical, ellipsoidal, quasi-spherical, sheet-like, petal-like, spherical-framework, spiky-spherical, pomegranate-like, or cactus-like.

[0012] In some embodiments, the carbon material and the metal material in the carbon and metal composite skeleton can be combined in the form of through-through, embedded, covered, or wrapped.

[0013] In some embodiments, the lithium alloy is one or more of the following: lithium-aluminum alloy, lithium-gold alloy, lithium-barium alloy, lithium-bismuth alloy, lithium-calcium alloy, lithium-gallium alloy, lithium-germanium alloy, lithium-mercury alloy, lithium-indium alloy, lithium-platinum alloy, lithium-silicon alloy, lithium-tin alloy, lithium-zinc alloy, lithium-lead alloy, lithium-antimony alloy, lithium-boron alloy, lithium-silver alloy, lithium-cadmium alloy, lithium-cobalt alloy, and lithium-magnesium alloy.

[0014] In some embodiments, the nucleating agent includes at least one of the following micro / nano particles: silver, aluminum, gold, barium, indium, bismuth, copper, tin, zinc, magnesium, silicon, germanium, lead, gallium, calcium, platinum, antimony, boron, chromium, cobalt, beryllium, cesium, iron, hafnium, potassium, manganese, molybdenum, sodium, nickel, titanium, vanadium, and zirconium. Preferred metal nucleating agents are micro / nano particles of silver, aluminum, indium, silicon, zinc, boron, and nickel.

[0015] In some embodiments, the mass ratio of carbon material skeleton: lithium and / or lithium alloy: metal nucleating agent in the bulk lithium-carbon material ranges from (5-85):(15-95):(0.1-5).

[0016] In some embodiments, the mass ratio of the carbon material skeleton to the metal nucleating agent in the carbon material layer ranges from (85-99):(1-15).

[0017] In some embodiments, the carbon material layer also includes a binder.

[0018] In some embodiments, the adhesive includes at least one of polyvinyl alcohol, polyvinylidene fluoride, polybutene styrene, polystyrene, polycarboxymethyl cellulose, cyanoacrylate, cyclodextrin, cyclic ether derivatives, polyurethane, methacrylate, epoxy resin, vinyl acetate polymer, polyimide, organofluoropolymer, organosiloxane, polyethylene glycol, polyethylene, polyvinyl chloride, polypropylene, glycerol, ethylparaben, and their derivatives.

[0019] In some embodiments, the solid electrolyte includes sulfide solid electrolytes and composite solid electrolytes of sulfide solid electrolytes and other solid electrolytes. Other solid electrolytes include organic solid electrolytes, halide solid electrolytes, lithium lanthanum zirconate, LiPON, and Li 1+x Al x Ge 2-x (PO4)3, Li-SiO glass, Li-Al-SO glass and other oxide solid electrolytes, etc.

[0020] In some embodiments, the cathode material includes: organic cathode materials (polypyrrole and its modified or composite, polyacrylonitrile and its modified or composite, anthraquinone and its modified or composite), and inorganic cathode materials (including lithium iron phosphate, lithium iron manganese phosphate, lithium titanate, lithium cobalt oxide, lithium manganese oxide, lithium nickel oxide, lithium nickel manganese oxide, lithium nickel cobalt manganese oxide, lithium nickel cobalt aluminum oxide, sulfur, and oxygen).

[0021] In summary, the present invention has at least the following advantages:

[0022] 1. The all-solid-state battery adopts a composite anode structure including a bulk material layer and a carbon material layer. The bulk material layer has a three-dimensional carbon material skeleton, which provides a fast channel for the deposition and extraction of metallic lithium on the surface and inside the bulk material layer.

[0023] 2. Lithium and / or lithium alloys in the bulk material provide reserve active lithium for lithium metal batteries, which can greatly extend the cycle life of lithium metal batteries.

[0024] 3. The carbon material layer has variable elasticity, which can provide space for newly deposited metallic lithium while effectively improving the interfacial contact between the bulk material layer and the solid electrolyte and reducing the contact resistance.

[0025] 4. By adjusting the quality and type of nucleating agents in the bulk material layer and carbon material layer, efficient and controllable deposition of lithium metal is achieved, effectively improving the defects of the lithium metal anode, enabling the all-solid-state battery to achieve high rate performance while also having longer cycle life and high safety. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of the power generation unit structure of an all-solid-state battery according to the present invention.

[0027] Figure 2 This is a schematic diagram of the bulk material layer of a lithium metal battery according to the present invention.

[0028] Figure 3 This is a schematic diagram of the carbon material layer in a lithium metal battery according to the present invention.

[0029] Figures 4 to 7 This is a scanning electron microscope (SEM) image of the carbon material used in the bulk material of this invention, wherein... Figure 4 The image shows a spherical multi-walled carbon nanotube framework. Figure 5 The image shows the framework of a composite material consisting of multi-walled carbon nanotubes and carbon whisker nanotubes. Figure 6 The image shows the framework of a graphene-multi-walled carbon nanotube composite material. Figure 7 The image shows a network of multi-walled carbon nanotube frameworks.

[0030] Figure 8 This is a scanning electron microscope image of the cross-sectional morphology of the bulk material after cycling in Example 1 of the all-solid-state battery.

[0031] Figure 9 This is a scanning electron microscope image of the cross-sectional morphology of the bulk material after cycling in Example 2 of the all-solid-state battery.

[0032] Figure 10 This is a scanning electron microscope image of the cross-sectional morphology of the bulk material after cycling in Example 3 of the all-solid-state battery.

[0033] Figure 11 The discharge capacity curves of all-solid-state batteries in Examples 1-3 and Comparative Examples 1-2 are shown. Detailed Implementation

[0034] The present invention will be further described in detail below with reference to embodiments. These embodiments are only for a better understanding of the principles of the invention and should not be construed as limiting the scope of protection of the invention. Any equivalent changes or substitutions made by those skilled in the art after reading the specification should be covered within the scope of the claims of this application.

[0035] The all-solid-state battery power generation unit structure provided by this invention is as follows: Figure 1 As shown in the figure, the all-solid-state battery power generation unit comprises a positive current collector, a positive electrode film, a solid electrolyte, a carbon material layer, and a bulk material layer arranged sequentially. On the negative electrode side, a lightweight carbon material is used to reconstruct the negative electrode structure of the all-solid-state battery in multiple layers. The negative electrode side includes a bulk material layer and a carbon material layer, both of which contain a carbon material framework and a nucleating agent. The bulk material layer also contains lithium and / or lithium alloys (see figure). Figure 2 and Figure 3 The bulk material layer and the carbon material layer can use the same or different carbon material framework and nucleating agent. The mass 'a' of the nucleating agent in the bulk material layer and the mass 'b' of the nucleating agent in the carbon material layer satisfy: a ≥ b, or the bonding bond energy Ea between the nucleating agent and lithium in the bulk material layer is higher than the bonding bond energy Eb between the nucleating agent and lithium in the carbon material layer. This guides the orderly and uniform deposition of metallic lithium inside the lithium-carbon composite anode. To ensure physical contact and electronic pathways between the layers of the lithium-carbon composite anode, the same carbon material is preferably used in both the bulk material layer and the carbon material layer.

[0036] Bulk material layer

[0037] The bulk material layer comprises a carbon material framework, lithium and / or lithium alloys, and a nucleating agent. A schematic diagram of the bulk material layer is shown below. Figure 2 As shown. The thickness of the bulk material layer is not specifically limited; it can be 500 micrometers, 300 micrometers, 200 micrometers, 50 micrometers, 15 micrometers, or 3 micrometers. The preferred thickness range is 10 micrometers to 170 micrometers.

[0038] The carbon material framework can be a pure micro / nano carbon material framework, including a single carbon material framework and a composite framework of multiple carbon materials; the carbon material framework can also be a composite framework of micro / nano carbon materials and metallic materials. Micro / nano carbon materials are at least one of the following: multi-walled carbon nanotubes, few-walled carbon nanotubes, single-walled carbon nanotubes, graphene, ordered mesoporous carbon, whisker carbon nanotubes, graphite, carbon black, and carbon fiber. Micro / nano carbon materials can be primary particles or aggregates prepared from combinations of primary particles.

[0039] Metallic materials are metals that do not react with lithium at room temperature or exist in stable compounds with lithium at room temperature, such as beryllium, chromium, cesium, iron, hafnium, potassium, manganese, molybdenum, sodium, nickel, titanium, vanadium, zirconium, copper, tantalum, tungsten, rhenium, osmium, niobium, ruthenium, and cobalt. The formation of the carbon-metal composite framework can be achieved using two methods. The first method involves first forming carbon particles, and then forming a metallic layer on the carbon surface using magnetron sputtering, physical vapor deposition, or similar techniques. The second method primarily uses metallic materials that do not react with lithium, which are melted and dispersed within a bulk matrix to form the carbon-metal composite framework.

[0040] The configuration of carbon material skeletons can be linear, coiled, network-like, spherical, ellipsoidal, quasi-spherical, sheet-like, petal-like, spherical-segmented, spiky-spherical, pomegranate-like, cactus-like, or a combination of multiple configurations of carbon material skeletons. Figures 4 to 7 Scanning electron microscope (SEM) images of several carbon material frameworks used in this invention are shown, wherein... Figure 4 The image shows a spherical multi-walled carbon nanotube framework. Figure 5 The image shows the framework of a composite material consisting of multi-walled carbon nanotubes and carbon whisker nanotubes. Figure 6 The image shows the framework of a graphene-multi-walled carbon nanotube composite material. Figure 7 It is a network of multi-walled carbon nanotube framework.

[0041] The lithium in lithium and / or lithium alloys is pure metallic lithium, excluding any alloying elements or having an alloying element mass percentage of less than 0.001%. Lithium alloys refer to materials containing metallic lithium and alloying elements. The combination of lithium and alloying elements can be a compound, a mixture, or a solid solution. The types of alloying elements are not specifically limited, but can include one or more of the following: aluminum, gold, barium, bismuth, calcium, gallium, germanium, mercury, indium, platinum, silicon, tin, zinc, lead, antimony, boron, silver, cadmium, cobalt, magnesium, scandium, strontium, yttrium, rhodium, palladium, iridium, thallium, and arsenic. It is worth noting that when lithium alloys are used in the bulk material layer, the deposited metallic lithium undergoes diffusion and rearrangement within the alloy phase, resulting in a uniform and dense dispersion of the deposited metallic lithium within the bulk material layer, similar to the function of a carbon material framework.

[0042] Nucleating agents primarily lower the nucleation barrier of lithium atoms, guiding the uniform and dense deposition of metallic lithium. The shape of the nucleating agent can be spherical, plate-like, or linear. The size of the nucleating agent is not specifically limited; it can be nanoscale or micrometer-scale particles. There are many types of nucleating agents, not limited by the preparation process. Preferred nucleating agents can react with metallic lithium at room temperature or form a solid solution, such as at least one of the following: silver, aluminum, gold, barium, indium, bismuth, copper, tin, zinc, magnesium, silicon, germanium, lead, gallium, calcium, platinum, antimony, boron, chromium, cobalt, beryllium, cesium, iron, hafnium, potassium, manganese, molybdenum, sodium, nickel, titanium, vanadium, and zirconium. Preferred metallic nucleating agents are silver, aluminum, indium, silicon, zinc, boron, and nickel.

[0043] There are many ways in which nucleating agents can bond with the carbon material framework. This can involve the carbon material physically coating the nucleating agent, or the nucleating agent coating or embedding itself on the carbon material surface. Bonding can occur through van der Waals forces and chemical bonds. Lithium and / or lithium alloys fill the gaps in the carbon material framework.

[0044] The mass ratio of carbon material skeleton to lithium and / or lithium alloy in the bulk material layer is not specifically limited. It can be 85:15, 90:10, 70:30, 50:50, or 15:85. The filling design can be made according to the performance of lithium-carbon composite anode.

[0045] In bulk lithium-carbon materials, the mass ratio of carbon material skeleton: lithium and / or lithium alloy: metal nucleating agent can be in the range of (5-85): (15-95): (0.1-5).

[0046] carbon material layer

[0047] The carbon material layer consists of a carbon material framework and a nucleating agent. A schematic diagram of the carbon material layer is shown below. Figure 3 As shown; the mass ratio of carbon material framework to nucleating agent is not specifically limited, and can be 90:10, 80:20, 95:5, or 70:30. The mass of nucleating agent in carbon material layer is less than or equal to the mass of nucleating agent in bulk material layer, and the bonding energy of nucleating agent in carbon material layer to lithium atom is lower than the bonding energy of nucleating agent in bulk material layer to lithium atom.

[0048] The carbon material framework in the carbon material layer can be the same as that in the bulk carbon material framework. Preferably, the micro / nano carbon material of the carbon material framework is one or more of multi-walled carbon nanotubes, few-walled carbon nanotubes, single-walled carbon nanotubes, graphene, ordered mesoporous carbon, whisker carbon nanotubes, graphite, carbon black, and carbon fiber. The carbon material can be lithiophilized to achieve good wettability with lithium atoms. Lithophilization treatment includes surface modification and atomic doping of the carbon material. There are no special requirements for the configuration of the carbon material. The thickness of the carbon material layer is not specifically limited; it can be 5 micrometers, 10 micrometers, or 25 micrometers, and can be designed and processed according to actual needs.

[0049] The nucleating agent in the carbon material layer can be the same as or different from the nucleating agent in the bulk layer. When the nucleating agents are the same, the mass 'a' of the nucleating agent in the bulk material layer and the mass 'b' of the nucleating agent in the carbon material layer satisfy: a ≥ b. When the nucleating agents are different, the bonding bond energy Ea between the nucleating agent in the bulk material layer and lithium is higher than the bonding bond energy Eb between the nucleating agent in the carbon material layer and lithium.

[0050] Nucleating agents are distributed inside the carbon material layer and can be combined with the carbon material skeleton in many ways. They can be physically coated with carbon materials, or the nucleating agents can be coated on or embedded on the surface of carbon materials. They can be combined through van der Waals forces and chemical bonds.

[0051] The carbon material layer may also contain other components such as a binder. The binder may be at least one of the following: polyvinyl alcohol, polyvinylidene fluoride, polybutene-styrene, polystyrene, polycarboxymethyl cellulose, cyanoacrylate, cyclodextrin, cyclic ether derivatives, polyurethane, methacrylate, epoxy resin, vinyl acetate polymer, polyimide, organofluoropolymer, organosiloxane, polyethylene glycol, polyethylene, polyvinyl chloride, polypropylene, glycerol, ethylparaben, and their derivatives.

[0052] There are two methods for preparing carbon material layers. The first method involves generating carbon nanotubes that are blown out of the reactor and electrostatically collected on a roller. Alcohol (e.g., an alcohol dispersion containing a nucleating agent) is then sprayed onto the rotating collection roller, and collection continues until the carbon material layer reaches a certain thickness. After drying, the carbon material layer is obtained. This method produces a carbon material layer containing only carbon material and a nucleating agent. The second method involves uniformly mixing carbon material, a binder, and a solvent, then coating the mixture onto a substrate. After drying and evaporating the solvent, a carbon material layer is formed. This method contains carbon material, a nucleating agent, and a binder.

[0053] solid electrolyte

[0054] Solid electrolytes primarily conduct lithium ions. Solid electrolytes include sulfide solid electrolytes and composite solid electrolytes combining sulfide solid electrolytes with other solid electrolytes. Other solid electrolytes include organic solid electrolytes, halide solid electrolytes, lithium lanthanum zirconate, LiPON, and Li 1+x Al x Ge 2-x (PO4)3, Li-SiO glass, Li-Al-SO glass and other oxide solid electrolytes, etc.

[0055] The sulfide solid electrolyte has a mass percentage of less than 35% or more than 75% in the solid electrolyte, with no specific limitation. When the mass percentage of sulfide solid electrolyte is less than 35%, its main function is to wet the grain boundaries and reduce the interfacial resistance of the solid electrolyte. When the mass percentage of sulfide solid electrolyte is more than 75%, the presence of the continuous phase of sulfide solid electrolyte significantly improves the internal ionic conductivity of the solid electrolyte. The addition of a small amount of other solid electrolytes can improve the stability and surface hardness of the solid electrolyte during processing, alleviate the oxidation of the solid electrolyte, and inhibit the formation of lithium dendrites. When the mass percentage of sulfide solid electrolyte is between 35% and 75%, the combination of sulfide solid electrolyte with other solid electrolytes creates more contact interfaces with other types of solid electrolytes. Due to the certain lag in lithium ion conduction at the interface, this leads to an increase in the internal interfacial resistance of the solid electrolyte.

[0056] Positive electrode film

[0057] The positive electrode film comprises a positive electrode material, a binder, and a conductive agent, and may also contain additives. Conventional positive electrode materials include organic materials (polypyrrole and its modified or composite forms, polyacrylonitrile and its modified or composite forms, anthraquinone and its modified or composite forms) and inorganic materials (including lithium iron phosphate, lithium iron manganese phosphate, lithium titanate, lithium cobalt oxide, lithium manganese oxide, lithium nickel oxide, lithium nickel manganese oxide, lithium nickel cobalt manganese oxide, and lithium nickel cobalt aluminum oxide). It is worth noting that sulfur and oxygen can also be used as positive electrode materials. The binder and conductive agent can be those commonly used in the battery technology field, without specific limitations.

[0058] current collector

[0059] The current collector primarily provides a good electron path. There are no special requirements for the material of the current collector; its thickness can be 2 micrometers, 15 micrometers, or 55 micrometers, without specific limitations. The current collector can be foil, mesh, or irregularly shaped material, without specific limitations. Preferred current collectors are one or more of the following: copper foil, aluminum foil, stainless steel foil, nickel foil, tin foil, carbon nanotube paper, carbon fiber paper, copper mesh, aluminum mesh, stainless steel mesh, nickel foam, and organic fiber films with metal-plated surfaces (such as copper-plated polyimide fiber films, silver-plated polyacrylonitrile films, etc.). Aluminum foil, stainless steel foil, and carbon nanotube paper are preferred.

[0060] The following specific embodiments illustrate the all-solid-state battery provided by the present invention.

[0061] Example 1

[0062] Positive electrode preparation

[0063] LiNi 0.8 Co 0.1 Mn 0.1 Using O2 as the positive electrode active material, polyvinylidene fluoride (PVDF) as a binder, and conductive carbon (SP) as a conductive agent, the positive electrode active material (PVDF):SP was dissolved in N-methylpyrrolidone (NMP) at a mass ratio of 96:2:2. The mixture was stirred until homogeneous to form a positive electrode slurry, which was then uniformly coated onto aluminum foil and dried to obtain a positive electrode sheet with a thickness of 120 micrometers. The resulting positive electrode was cut to a size of 4.1 cm × 5.6 cm, with an on-area capacity of 3 mAh / cm². 2 .

[0064] Preparation of negative electrode

[0065] Step 1: Carbon nanotubes (GTC-304 from Shandong Dazhan Materials Co., Ltd.), serving as the carbon material framework, are uniformly dispersed in molten lithium containing a silver nucleating agent (secondary particle D50 of 10 micrometers). The mass ratio of carbon material framework: silver nucleating agent: lithium is 3:1:17. After uniform dispersion, the melt is cast and rolled into a bulk material film with a thickness of 50 micrometers, or the film is rolled into a single unit with a current collector and rolled on both sides.

[0066] It is particularly important to emphasize that the carbon material framework used in this step can be finely designed by changing the configuration of the carbon material to give the bulk material layer different structural strengths and electrochemical properties. Figures 4 to 7 These are carbon materials with different configurations prepared in the experiment. Figure 4 The particles were prepared by spray granulation of carbon nanotube materials. Figure 5 It was prepared by ball milling carbon nanotubes and carbon whisker tubes; Figure 6 It is prepared by combining carbon nanotubes and graphene materials; Figure 7 It is prepared by dispersing carbon nanotube materials. The carbon material used in the examples is... Figure 4 The materials shown.

[0067] Step 2: Single-walled carbon nanotubes (Miaosika (Shenzhen) Technology Co., Ltd.) and metallic silver particles (Suzhou Nofi Nanotechnology Co., Ltd., particle size 80nm) are uniformly dispersed in N-methylpyrrolidone containing polyvinylidene fluoride, with a mass ratio of single-walled carbon nanotubes: metallic silver particles: polyvinylidene fluoride of 10:2:5. The above-dispersed slurry is uniformly coated on the surface of the bulk material layer to a thickness of 100 micrometers. After drying, it is rolled to obtain a film with a carbon material layer on the surface of the bulk material layer.

[0068] Preparation of solid electrolyte membranes

[0069] Li5PS4Cl in a mass ratio of 15:85 1.5 (BH4)0.5 and Li7La3Zr2O 12 (LLZO) solid electrolyte was ball-milled in n-hexane solvent for 24 hours, then cast in a fixed-size mold and dried to produce a solid electrolyte film.

[0070] A positive and negative all-solid-state battery was assembled using the above-mentioned positive electrode, negative electrode and solid electrolyte membrane, and then cycled after formation.

[0071] The tested battery was disassembled, the bulk material was removed, and the sample was cut using a focused ion beam (FIB) and observed. The cross-section of the cut sample is shown below. Figure 8 As shown in the figure, dense lithium metal is deposited inside the intermediate bulk material layer, and aggregates of carbon material can be seen inside the bulk material layer. Figure 4 The morphology is similar. A small amount of white skeleton residue remains on the surface of the bulk material, which may be the combination product of electrolyte decomposition and carbon material, and is caused by residue left on the surface of the bulk material during the disassembly process. This indicates that the newly deposited metallic lithium is mainly deposited on the bulk material layer, with less deposition on the carbon material layer. The negative electrode structure constructed by this invention can achieve ordered, dense, and controllable deposition of metallic lithium on the negative electrode side.

[0072] Example 2

[0073] Other conditions remain the same as in Example 1, except that the mass of the nucleating agent in the bulk material layer is reduced so that the mass ratio of carbon material skeleton: metallic silver nucleating agent: lithium is 5:1:17.

[0074] The cycled battery was disassembled, and the bulk material layers after cycling were observed as described in Example 1. Figure 9As shown in the figure, reducing the mass of nucleating agent in the bulk material layer results in the deposited lithium metal in the form of particles or clusters. The newly deposited lithium metal is loosely deposited on the surface, while the interior of the bulk material layer remains dense. There are large gaps between the dense interior layer and the loose surface layer. Therefore, reducing the nucleating agent in the bulk material layer leads to the loose deposition of lithium metal in the bulk material layer.

[0075] Example 3

[0076] Other conditions remained consistent with Example 1, except that no nucleating agents were used in the bulk material layer and the carbon material layer. The cycled battery was disassembled and observed in the same manner as in Example 1. Figure 10 As shown in the figure, the newly deposited lithium metal exhibits a dendritic structure and is loosely deposited on the surface, with significant gaps between the loose layer and the underlying dense layer. This indicates that without the use of nucleating agents, the morphology of lithium metal deposition transforms from granular or clustered to dendritic.

[0077] Comparative Example 1

[0078] Other conditions remained the same as in Example 1, except that a commercially available lithium metal anode was used instead of the bulk material layer.

[0079] Comparative Example 2

[0080] Other conditions remain the same as in Example 1, except that no carbon material layer is provided on the bulk material layer.

[0081] The assembled lithium metal battery was formed and subjected to charge-discharge tests. Battery discharge capacity data was collected and plotted. The battery charge-discharge steps were as follows: rest for 5 minutes, charge to 4.35V at 0.05C, rest for 5 minutes, discharge to 2.8V at 0.1C, and repeat the above steps until the cycle ends.

[0082] Figure 11The figures show the discharge capacity curves of the all-solid-state batteries in various embodiments and comparative examples of this invention during cycling. As can be seen from the figures, the all-solid-state battery in Example 1 exhibits the best performance, while the all-solid-state battery in Example 2 performs slightly worse, with similar initial capacities. However, the cycling performance of Example 3 and Comparative Example 1 is very poor, with both showing a decrease followed by an increase in capacity after the start of cycling. Example 3 does not use a nucleating agent and uses a carbon material layer. Metallic lithium does not easily form a stable solid electrolyte membrane (SEI) on the carbon material layer, thus requiring more cycles to form a stable SEI. This undoubtedly leads to a loss of positive electrode capacity. Although the active lithium stored in the bulk material layer can compensate for the positive electrode capacity loss, it cannot compensate for the battery's consumption. Comparative Example 1 uses pure metallic lithium, resulting in a large amount of dendrites and "dead lithium" during cycling. After cycling for a period of time, the all-solid-state battery temporarily reaches a steady state, and its capacity briefly recovers. Comparative Example 1 uses pure metallic lithium, and at the same thickness, the active lithium content is higher than that in the bulk material. Therefore, the number of cycles in Comparative Example 1 is slightly increased. In Comparative Example 2, no carbon material layer was added, resulting in very poor contact between the negative electrode and the solid electrolyte. Furthermore, the bulk material had a higher hardness than the pure metallic lithium in Comparative Example 1, leading to a larger internal resistance in the all-solid-state battery. Consequently, the discharge capacity decayed very quickly at the start of cycling.

[0083] Based on the disclosure and teachings of the foregoing specification, those skilled in the art can make appropriate changes and modifications to the above embodiments. Therefore, the present invention is not limited to the specific embodiments disclosed and described above, and some modifications and changes to the present invention should also fall within the protection scope of the claims of the present invention. Furthermore, although some specific terms are used in this specification, these terms are only for convenience of explanation and do not constitute any limitation on the present invention.

Claims

1. An all-solid-state battery, characterized in that, The all-solid-state battery includes at least one power generation unit, which comprises a positive current collector, a positive electrode film, a solid electrolyte, a carbon material layer, and a bulk material layer. The bulk material layer comprises lithium and / or lithium alloy, a carbon material framework, and a nucleating agent, wherein the carbon material layer comprises a carbon material framework and a nucleating agent. The carbon material framework and nucleating agent in the bulk material layer and the carbon material layer can be the same or different. The mass a of the nucleating agent in the bulk material layer and the mass b of the nucleating agent in the carbon material layer satisfy: a≥b, or the binding bond energy Ea between the nucleating agent and lithium in the bulk material layer is higher than the binding bond energy Eb between the nucleating agent and lithium in the carbon material layer.

2. The all-solid-state battery according to claim 1, characterized in that, The carbon material framework in the bulk material layer is at least one of micro / nano carbon material framework or composite framework of micro / nano carbon material and metal material; the carbon framework in the carbon material layer is a micro / nano carbon material framework. The micro / nano carbon material is at least one of the following: multi-walled carbon nanotubes, few-walled carbon nanotubes, single-walled carbon nanotubes, graphene, ordered mesoporous carbon, whisker carbon nanotubes, graphite, carbon black, and carbon fiber. The metal materials mentioned are those that do not react with lithium metal at room temperature or exist in a stable compound with lithium metal at room temperature, including: beryllium, chromium, cesium, iron, hafnium, potassium, manganese, molybdenum, sodium, nickel, titanium, vanadium, zirconium, and copper; The carbon and metal materials in the micro / nano carbon and metal composite framework are combined in the form of penetrating, embedding, covering, and entanglement. The configurations of the carbon material skeleton include: linear, coiled, net-like, spherical, ellipsoidal, quasi-spherical, sheet-like, petal-like, spherical-framework, spiky-spherical, pomegranate-like, and cactus-like.

3. The all-solid-state battery according to claim 1, characterized in that, The lithium alloy is one or more of the following: lithium-aluminum alloy, lithium-gold alloy, lithium-barium alloy, lithium-bismuth alloy, lithium-calcium alloy, lithium-gallium alloy, lithium-germanium alloy, lithium-mercury alloy, lithium-indium alloy, lithium-platinum alloy, lithium-silicon alloy, lithium-tin alloy, lithium-zinc alloy, lithium-lead alloy, lithium-antimony alloy, lithium-boron alloy, lithium-silver alloy, lithium-cadmium alloy, lithium-cobalt alloy, and lithium-magnesium alloy.

4. The all-solid-state battery according to claim 1, characterized in that, The nucleating agent includes at least one of the following micro / nano particles: silver, aluminum, gold, barium, indium, bismuth, copper, tin, zinc, magnesium, silicon, germanium, lead, gallium, calcium, platinum, antimony, boron, chromium, cobalt, beryllium, cesium, iron, hafnium, potassium, manganese, molybdenum, sodium, nickel, titanium, vanadium, and zirconium, preferably silver, aluminum, indium, silicon, zinc, boron, or nickel.

5. The all-solid-state battery according to claim 1, characterized in that, The mass ratio of carbon material skeleton, lithium and / or lithium alloy, to metal nucleating agent in the bulk lithium-carbon material is in the range of (5-85):(15-95):(0.1-5). The mass ratio of the carbon material skeleton to the nucleating agent in the carbon material layer is (85-99):(1-15).

6. The all-solid-state battery according to claim 1, characterized in that, The carbon material layer also includes a binder.

7. The all-solid battery according to claim 6, characterized by The adhesive comprises at least one of polyvinyl alcohol, polyvinylidene fluoride, polybutene styrene, polystyrene, polycarboxycellulose, cyanoacrylate, cyclodextrin, cyclic ether derivatives, polyurethane, methacrylate, epoxy resin, vinyl acetate polymer, polyimide, organofluoropolymer, organosiloxane, polyethylene glycol, polyethylene, polyvinyl chloride, polypropylene, glycerol, ethylparaben, and their derivatives.

8. The all-solid battery according to claim 1, characterized by, The solid electrolyte includes sulfide solid electrolytes and composite solid electrolytes of sulfide solid electrolytes and other solid electrolytes. Other solid electrolytes include organic solid electrolytes, halide solid electrolytes, lithium lanthanum zirconate, LiPON, and Li 1+x Al x Ge 2-x (PO4)3, Li-SiO glass, Li-Al-SO glass.

9. The all-solid battery according to claim 1, characterized by, The positive electrode material in the positive electrode membrane includes: organic positive electrode materials and inorganic positive electrode materials.

10. The all-solid battery according to claim 9, characterized by, The organic cathode materials include polypyrrole and its modified or composite materials, polyacrylonitrile and its modified or composite materials, and anthraquinone and its modified or composite materials; the inorganic cathode materials include lithium iron phosphate, lithium iron manganese phosphate, lithium titanate, lithium cobalt oxide, lithium manganese oxide, lithium nickel oxide, lithium nickel manganese oxide, lithium nickel cobalt manganese oxide, lithium nickel cobalt aluminum oxide, sulfur, and oxygen.

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