Electrode-electrolyte integrated material, electrochemical device, and electric device

Abstract

The invention discloses an electrode-electrolyte integrated material, an electrochemical device and an electric device, and belongs to the technical field of energy storage. The electrode-electrolyte integrated material provided by the invention comprises a three-dimensional fiber network carrier, and a negative electrode active layer, an interface transition layer and a solid electrolyte layer which are sequentially arranged in the carrier, the thickness ratio of the negative electrode active layer to the solid electrolyte layer is limited, and the interface transition layer comprises lithium-loving particles. A negative electrode and electrolyte integrated interface interpenetrating structure can be formed, a continuous ion path is formed on the basis of a three-dimensional fiber network carrier, continuous and efficient ion transmission can be effectively achieved in cooperation with introduction of an interface transition layer, and meanwhile growth of lithium dendrites can be inhibited; therefore, the rate capability and the cycle performance of the electrochemical device prepared subsequently are effectively improved.

Description

Technical Field

[0001] This application relates to the field of energy storage technology, particularly to electrode-electrolyte integrated materials, electrochemical devices, and electrical devices. Background Technology

[0002] All-solid-state lithium batteries, as a core direction of next-generation energy storage technology, focus on using solid electrolytes to replace liquid electrolytes, fundamentally solving safety issues. However, one of the biggest challenges facing all-electrochemical devices is the solid-solid interface contact problem. During charging and discharging, volume changes in the positive / negative electrode materials lead to interfacial stress accumulation, further deteriorating the interfacial contact. On the other hand, lithium metal, with its ultra-high theoretical specific capacity and lowest redox potential, has become the most promising candidate for anode. However, lithium-ion deposition during cycling often occurs on the lithium metal surface in a dendritic, non-uniform form. Among these strategies, constructing a three-dimensional lithium metal deposition framework can effectively inhibit the growth of anode dendrites by regulating the uniform deposition of lithium ions. Summary of the Invention

[0003] The purpose of this application is to solve the technical problems of large internal resistance at the solid-solid interface in the prior art and the easy formation of lithium dendrites during lithium metal cycling. In order to propose an integrated electrode-electrolyte material, electrochemical device and electrical device with good interfacial contact, high ion transport efficiency and excellent cycling performance.

[0004] To achieve the above objectives, the first aspect of this application proposes an integrated electrode-electrolyte material, comprising a three-dimensional fiber network carrier, and a negative electrode active layer, an interface transition layer, and a solid electrolyte layer sequentially disposed within the carrier. The thickness ratio of the negative electrode active layer to the solid electrolyte layer is 1:(0.2-1.5). The interface transition layer comprises lithium-philic nanoparticles.

[0005] As an embodiment of this application, the thickness of the negative electrode active layer is 20-150 μm.

[0006] As an embodiment of this application, the thickness of the solid electrolyte layer is 10-100 μm.

[0007] As an embodiment of this application, the average particle size of the lithiophilic nanoparticles is 20-500 nm.

[0008] As an embodiment of this application, the lithium-loving nanoparticles include at least one of tin, silver, and tin fluoride.

[0009] As an embodiment of this application, the negative electrode active layer comprises lithium metal.

[0010] As an embodiment of this application, the mass percentage of the lithium-loving nanoparticles is 0.5-15% based on the mass of the lithium.

[0011] As an embodiment of this application, the solid electrolyte layer includes an electrolyte comprising polyethylene oxide and lithium bis(trifluoromethanesulfonyl)imide.

[0012] As an embodiment of this application, the polyoxyethylene is characterized in that, based on the mass of the three-dimensional fiber network carrier, the mass percentage of the polyoxyethylene is 20-80%.

[0013] As an embodiment of this application, the mass ratio of lithium bis(trifluoromethanesulfonyl)imide to polyethylene oxide is 1:(2-8).

[0014] As an embodiment of this application, the porosity of the electrode-electrolyte integrated material is 40-85%.

[0015] As an embodiment of this application, the average diameter of the fibers in the three-dimensional fiber network carrier is 100-2000 nm.

[0016] As an embodiment of this application, the raw material of the three-dimensional fiber network carrier includes at least one of polyacrylonitrile, polyvinylidene fluoride, polyvinylidene fluoride-hexafluoropropylene, and polyimide.

[0017] In a second aspect of this application, an electrochemical device is provided, the electrochemical device comprising the electrode-electrolyte integrated material described in this application.

[0018] In a third aspect of this application, an electrical device is provided, including the electrochemical device described in this application.

[0019] Compared with the prior art, the beneficial effects of this application are: This application provides an integrated electrode-electrolyte material comprising a three-dimensional fiber network carrier, and a negative electrode active layer, an interface transition layer, and a solid electrolyte layer sequentially disposed within the carrier. The thickness ratio of the negative electrode active layer to the solid electrolyte layer is defined as 1:(0.2-1.5). The interface transition layer comprises lithium-philic nanoparticles, which can form an interpenetrating structure of the integrated negative electrode and electrolyte interface. Based on the three-dimensional fiber network carrier, a continuous ion pathway is formed. With the introduction of the interface transition layer, continuous and efficient ion transport can be effectively achieved, while suppressing the growth of lithium dendrites. This effectively improves the rate performance and cycle performance of the electrochemical device subsequently prepared. Detailed Implementation

[0020] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions in the embodiments of this application will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0021] The term "polymer" refers to a polymeric compound prepared by polymerizing the same or different types of monomers. The general term "polymer" includes the terms "homopolymer," "copolymer," "trimer," and "interpolymer."

[0022] The term "binder" refers to a substance used to bind inorganic fillers to or to porous substrate materials.

[0023] In this application, the technical features described in an open-ended manner include both closed technical solutions consisting of the listed features and open technical solutions that include the listed features.

[0024] In this application, the technical features described in an open-ended manner include both closed technical solutions consisting of the listed features and open technical solutions that include the listed features.

[0025] As used herein, the terms “approximately,” “generally,” “substantially,” and “about” are used to describe and indicate small variations. When used in conjunction with an event or situation, the terms may refer to examples in which the event or situation occurred precisely and examples in which the event or situation occurred very approximately. For example, when used in conjunction with numerical values, the terms may refer to a range of variation less than or equal to ±10% of the numerical value, such as less than or equal to ±5%, less than or equal to ±4%, less than or equal to ±3%, less than or equal to ±2%, less than or equal to ±1%, less than or equal to ±0.5%, less than or equal to ±0.1%, or less than or equal to ±0.05%. For example, if the difference between two values ​​is less than or equal to ±10% of the average of the values ​​(e.g., less than or equal to ±5%, less than or equal to ±4%, less than or equal to ±3%, less than or equal to ±2%, less than or equal to ±1%, less than or equal to ±0.5%, less than or equal to ±0.1%, or less than or equal to ±0.05%), then the two values ​​can be considered "substantially" the same.

[0026] Furthermore, for ease of description, "first," "second," "third," etc., can be used in this article to distinguish different components of a figure or a series of figures. "First," "second," "third," etc., are not intended to describe the corresponding components.

[0027] Additionally, quantities, ratios, and other numerical values ​​are sometimes presented in range format in this document. It should be understood that such range format is for convenience and brevity and should be interpreted flexibly to include not only the numerical values ​​explicitly specified as range limits, but also all individual numerical values ​​or subranges covered within the range, as if each numerical value and subrange were explicitly specified.

[0028] In the detailed description and claims, a list of items connected by the terms "one of," "among," "a kind of," or other similar terms may mean any of the listed items. For example, if items A and B are listed, then the phrase "one of A and B" means only A or only B. In another example, if items A, B, and C are listed, then the phrase "one of A, B, and C" means only A; only B; or only C. Item A may contain a single element or multiple elements. Item B may contain a single element or multiple elements. Item C may contain a single element or multiple elements.

[0029] In the detailed description and claims, the list of items connected by the term "at least one of" can mean any combination of the listed items. For example, if items A and B are listed, then the phrase "at least one of A and B" means only A; only B; or A and B. In another example, if items A, B, and C are listed, then the phrase "at least one of A, B, and C" means only A; or only B; only C; A and B (excluding C); A and C (excluding B); B and C (excluding A); or all of A, B, and C.

[0030] In the following description, all figures disclosed in this application are approximate values, regardless of whether the terms "about" or "approximately" are used in conjunction. They may vary by 1%, 2%, 5%, or sometimes 10% to 20%. Whenever a range of values ​​with a lower limit (RL) and an upper limit (RU) is disclosed, any values ​​falling within that range are specifically disclosed. Specifically, the following values ​​within this range are specifically disclosed: R = RL + k * (RU - RL), where k is a variable ranging from 1% to 100% with a 1% increment, i.e., k is 1%, 2%, 3%, 4%, 5%, ..., 50%, 51%, 52%, ..., 95%, 96%, 97%, 98%, 99%, or 100%. Furthermore, any range of values ​​defined by the two R values ​​as defined above are also specifically disclosed.

[0031] Throughout this specification, references to "implementation," "partial implementation," "one implementation," "another implementation," "specific method," or "partial method" mean that at least one implementation or embodiment in this application includes the specific features, structures, materials, or characteristics described in that implementation or embodiment.

[0032] In this application, numerical ranges are involved. Unless otherwise specified, the numerical ranges mentioned above are considered continuous and include the minimum and maximum values ​​of the range, as well as every value between the minimum and maximum values. Any lower limit can be combined with any upper limit to form a range not explicitly stated; and any lower limit can be combined with other lower limits to form a range not explicitly stated, just as any upper limit can be combined with any other upper limit to form a range not explicitly stated. Furthermore, each individually disclosed point or single value can itself serve as a lower or upper limit and be combined with any other point or single value or with other lower or upper limits to form a range not explicitly stated.

[0033] Unless otherwise specified, all reagents or instruments used in this application are commercially available products.

[0034] In one embodiment of this application, an integrated electrode-electrolyte material is provided, comprising a three-dimensional fiber network carrier, and a negative electrode active layer, an interface transition layer, and a solid electrolyte layer sequentially disposed within the carrier. The thickness ratio of the negative electrode active layer to the solid electrolyte layer is 1:(0.2-1.5). The interface transition layer comprises lithium-philic nanoparticles.

[0035] The electrode-electrolyte integrated material provided in this application includes a three-dimensional fiber network carrier, and a negative electrode active layer, an interface transition layer, and a solid electrolyte layer sequentially disposed within the carrier. The thickness ratio of the negative electrode active layer to the solid electrolyte layer is defined as 1:(0.2-1.5). The interface transition layer includes lithium-philic nanoparticles, which can form an interpenetrating structure of the negative electrode and electrolyte integrated interface. Based on the three-dimensional fiber network carrier, a continuous ion pathway is formed. With the introduction of the interface transition layer, continuous and efficient ion transport can be effectively achieved, while inhibiting the growth of lithium dendrites. This effectively improves the rate performance and cycle performance of the electrochemical device subsequently prepared.

[0036] Specifically, the three-dimensional fiber network carrier provided in this application enables the integration of the skeletal structure between the negative electrode active layer and the electrolyte layer. Based on the interpenetrating nanofibers forming a continuous ion pathway, compared to conventional stacked structures, it achieves efficient and continuous ion transport and suppresses lithium dendrite growth. Furthermore, the interface transition layer includes lithiophilic nanoparticles, which can form a lithium alloy phase in situ that is conducive to ion transport. This further ensures a tight bond between the interface transition layer, the negative electrode active layer, and the three-dimensional fiber network carrier. Due to the difference in distance from the negative electrode active layer, the lithiophilic nanoparticles in the interface transition layer exhibit a gradient distribution, thereby further improving ion transport efficiency. Moreover, within a certain range, the thickness ratio of the negative electrode active layer to the solid electrolyte layer can effectively suppress lithium dendrite formation while providing sufficient lithium storage capacity. This results in an electrochemical device with excellent cycle performance and rate performance.

[0037] It should be noted that the test method for the thickness ratio of the negative electrode active layer and the solid electrolyte layer is as follows: the cross-section of the electrode-electrolyte integrated material is characterized by CP-SEM (cold field emission scanning electron microscope). In the obtained cross-sectional SEM image, the thickness of the negative electrode active layer and the solid electrolyte layer are measured along the direction perpendicular to the layer. The thickness of each layer is measured at no less than 5 different locations and the arithmetic mean is taken. The thickness ratio of the two is then calculated.

[0038] For example, the thickness ratio of the negative electrode active layer to the solid electrolyte layer can be any point value between 1 and (0.2-1.5) or a range value between any two points, such as 1:0.2, 1:0.5, 1:0.8, 1:1, 1:1.2, 1:1.5, etc.

[0039] In one embodiment, the thickness ratio of the negative electrode active layer to the solid electrolyte layer is 1:(0.5-0.8). For example, it can be 1:0.5, 1:0.6, 1:0.7, 1:0.8, etc.

[0040] This study found that the thickness ratio of the negative electrode active layer to the solid electrolyte layer affects the volume change of the subsequently prepared electrochemical device during cycling; it also affects the magnitude of the interfacial impedance, thereby affecting the growth of lithium dendrites; when the thickness ratio of the negative electrode active layer to the solid electrolyte layer is further selected within the range of this application, especially within the further preferred range, the volume change and mechanical stress matching degree of the obtained electrochemical device are high, thereby effectively improving the cycling performance and rate performance of the electrochemical device.

[0041] In one embodiment, the thickness of the negative electrode active layer is 20-150 μm.

[0042] For example, the thickness of the negative electrode active layer can be any point value or a range between any two points between 20-150 μm, such as 20 μm, 40 μm, 60 μm, 80 μm, 100 μm, 120 μm, 140 μm, 150 μm, etc.

[0043] This study found that the thickness of the negative electrode active layer affects the length of the ion transport path and also affects the degree of volume expansion during subsequent cycling. When the thickness of the negative electrode active layer is further selected within the above range, the cycling performance and rate performance of the electrochemical device prepared subsequently are better.

[0044] In one embodiment, the thickness of the solid electrolyte layer is 10-100 μm.

[0045] For example, the thickness of the solid electrolyte layer can be any point value or any two-point range value between 10-100μm, such as 10μm, 20μm, 30μm, 40μm, 50μm, 60μm, 70μm, 80μm, 90μm, 100μm, etc.

[0046] This study found that the thickness of the solid electrolyte layer affects the mechanical strength, as well as the interfacial impedance and the length of the ion transport path. When the thickness of the solid electrolyte layer is selected within the above range, the cycle performance and rate performance of the electrochemical device prepared subsequently are better.

[0047] In one embodiment, the average particle size of the lithiophilic nanoparticles is 20-500 nm.

[0048] It should be noted that the average particle size of the lithium-loving nanoparticles is tested by: electrochemically delithiating the electrode-electrolyte integrated material to remove the metallic lithium phase, cleaning it with anhydrous ethanol, and then characterizing the cross-section of the material using CP-SEM, and statistically measuring the observed particle size.

[0049] For example, the average particle size of the lithiophilic nanoparticles can be any point value between 20-500 nm or a range between any two points, such as 20 nm, 80 nm, 140 nm, 200 nm, 260 nm, 320 nm, 380 nm, 440 nm, 500 nm, etc.

[0050] This study found that the average particle size of lithiophilic nanoparticles affects their aggregation ability, thereby affecting their stability and ability to alloy with lithium metal; it also affects the structural stability of the deposited layer, thereby affecting the overall mechanical strength and stability; when the average particle size of lithiophilic nanoparticles is further selected within the above range, the cycle performance and rate performance of the electrochemical device prepared subsequently are better.

[0051] In one embodiment, the lithiophilic nanoparticles include at least one of tin, silver, and tin fluoride.

[0052] It should be noted that the testing method for the type of lithiophilic nanoparticles is as follows: CP-SEM and its attached EDS (energy-dispersive spectroscopy) are used to perform elemental surface distribution analysis on the cross-section of the electrode-electrolyte integrated material. By identifying the uniform distribution characteristics of at least one of tin, silver, and fluorine elements, the phase of the electrode-electrolyte integrated material is identified by XRD (X-ray diffraction analysis). By detecting the characteristic diffraction peaks of at least one of lithium-tin alloy, lithium-silver alloy, or lithium fluoride phase, it is confirmed that the corresponding lithiophilic nanoparticles have participated in the reaction and formed the corresponding functional alloy phase.

[0053] This study found that the type of lithiophilic nanoparticles affects their ability to alloy with lithium, as well as their ionic and electronic conductivity; in addition, it also affects the structural stability of the system; when lithiophilic nanoparticles are further selected to be of the above-mentioned type, the cycle performance and rate performance of the electrochemical device prepared subsequently are better.

[0054] In one embodiment, the negative electrode active layer comprises lithium metal.

[0055] In one embodiment, the mass percentage of the lithium-loving nanoparticles is 0.5-15% based on the mass of the lithium.

[0056] It should be noted that, based on the mass of lithium, the method for testing the mass percentage of the lithium-loving nanoparticles is as follows: the electrolyte layer in the electrode-electrolyte integrated material is soaked and cleaned with anhydrous dimethyl carbonate (DMC), and then the mass fractions of Sn, Ag, F and Li in the soaked sample are accurately determined by ICP-OES (inductively coupled plasma optical emission spectroscopy).

[0057] For example, the mass percentage of the lithium-loving nanoparticles can be any point value or a range between any two points between 0.5% and 15%, such as 0.5%, 3%, 6%, 9%, 12%, 15%, etc.

[0058] This application research found that, based on the mass of lithium, the mass percentage of the lithiophilic nanoparticles affects the degree of lithium alloying, thereby affecting the formation of lithium dendrites and ion transport efficiency; when the mass percentage of the lithiophilic nanoparticles based on the mass of lithium is further selected to be within the above range, the overall performance of the electrochemical device subsequently prepared is better.

[0059] In one embodiment, the solid electrolyte layer includes an electrolyte comprising polyethylene oxide and lithium bis(trifluoromethanesulfonyl)imide.

[0060] This study found that the ionic conductivity and interfacial compatibility of solid electrolytes are key factors determining the performance of electrochemical devices. When electrolytes including polyethylene oxide and lithium bis(trifluoromethanesulfonyl)imide are selected, the resulting electrochemical device exhibits excellent interfacial wettability and chemical stability between the electrolyte and the integrated negative electrode layer, and can maintain a stable interfacial structure during cycling, thereby effectively improving the cycling performance of the subsequently prepared electrochemical device.

[0061] In one embodiment, the polyethylene oxide has a mass percentage of 20-80% based on the mass of the three-dimensional fiber network carrier.

[0062] It should be noted that, based on the mass of the three-dimensional fiber network carrier, the method for testing the mass percentage of polyethylene oxide is as follows: the electrolyte layer in the electrode-electrolyte integrated material is soaked and cleaned with anhydrous dimethyl carbonate (DMC), and the carbon (C) element is quantified using an elemental analyzer (EA) to obtain the mass of ethylene oxide. Further, the lithium and alloy in the negative electrode active layer are completely dissolved with dilute hydrochloric acid or a nitric acid-ethanol mixture, and the remaining solid is weighed to obtain the total mass of the three-dimensional fiber network carrier; subsequently, the mass percentage of polyethylene oxide in the three-dimensional fiber network carrier is calculated.

[0063] For example, based on the mass of the three-dimensional fiber network carrier, the mass percentage of the polyethylene oxide can be any point value or any two-point range value between 20% and 80%, such as 20%, 30%, 40%, 50%, 60%, 70%, 80%, etc.

[0064] This study found that, based on the mass percentage of the three-dimensional fiber network carrier, the mass percentage of the polyethylene oxide affects the lithium-ion transport efficiency, as well as the flexibility of the electrolyte layer and its interfacial contact capability with the electrode. When the mass percentage is further selected within the above range, the overall performance of the electrochemical device is better.

[0065] In one embodiment, the mass ratio of lithium bis(trifluoromethanesulfonylimide) to polyethylene oxide is 1:(2-8).

[0066] It should be noted that the method for testing the mass ratio of lithium bis(trifluoromethanesulfonylimide) to polyethylene oxide is as follows: the electrolyte layer in the electrode-electrolyte integrated material is soaked and cleaned with anhydrous dimethyl carbonate (DMC), and the carbon (C) element is quantified by an elemental analyzer (EA) and the fluorine (F) element is quantified by inductively coupled plasma optical emission spectrometry (ICP-OES). The mass is then inferred from the characteristic stoichiometric relationship between the two.

[0067] For example, the mass ratio of lithium bis(trifluoromethanesulfonyl)imide to polyethylene oxide can be any point value between 1:(2-8) or a range value between any two points, such as 1:2, 1:3, 1:4, 1:5, 1:6, 1:7, 1:8, etc.

[0068] This study found that the mass ratio of lithium bis(trifluoromethanesulfonyl)imide to polyethylene oxide (PEO) affects the presence and mobility of lithium ions in the microenvironment surrounding PEO segments. When the mass ratio of lithium bis(trifluoromethanesulfonyl)imide to PEO is further selected within the above range, sufficient lithium ions are dissociated to become charge carriers. At the same time, lithium ions can effectively interact with PEO segments, inhibiting PEO crystallization and promoting the formation of amorphous regions, thereby creating more ion migration channels, improving ionic conductivity, and thus enhancing the rate performance of the resulting electrochemical device. In addition, it can also help form a stable, uniform, and lithium fluoride-rich SEI film, thereby improving the cycle performance of the electrochemical device.

[0069] In one embodiment, the porosity of the electrode-electrolyte integrated material is 40-85%.

[0070] It should be noted that the test method for the porosity of the electrode-electrolyte integrated material is as follows: the electrolyte layer in the electrode-electrolyte integrated material is soaked and cleaned with anhydrous dimethyl carbonate (DMC), and the lithium and alloy of the negative electrode active layer are completely dissolved with dilute hydrochloric acid or nitric acid-ethanol mixture. The porosity of the negative electrode / electrolyte integrated carrier material is then tested by mercury intrusion porosimetry or a true density meter.

[0071] For example, the porosity of the electrode-electrolyte integrated material can be any point value or a range between any two points between 40% and 85%, such as 40%, 50%, 60%, 70%, 80%, 85%, etc.

[0072] This application research found that the porosity of the electrode-electrolyte integrated material can provide a diffusion path for lithium ions within the active material and electrolyte, and an appropriate porosity can reduce ion transport impedance. At the same time, porosity can buffer volume expansion during charging and discharging. In addition, it also affects the volumetric energy density and the local tip effect formed by lithium metal deposition, thus affecting the growth of lithium dendrites. When the porosity of the electrode-electrolyte integrated material is further selected within the above range, the cycle performance and rate performance of the obtained electrochemical device are better.

[0073] In one embodiment, the average diameter of the fibers in the three-dimensional fiber network carrier is 100-2000 nm.

[0074] It should be noted that the test method for the average fiber diameter in the three-dimensional fiber network carrier is as follows: the electrolyte layer in the electrode-electrolyte integrated material is soaked and cleaned with anhydrous dimethyl carbonate (DMC), and the lithium and alloy of the negative electrode active layer are completely dissolved with dilute hydrochloric acid or nitric acid-ethanol mixture. The morphology is characterized by SEM, and the fiber diameter in the image is measured.

[0075] For example, the average diameter of the fibers in the three-dimensional fiber network carrier can be any point value or any two-point range value between 100-2000nm, such as 100nm, 500nm, 900nm, 1300nm, 1700nm, 2000nm, etc.

[0076] This application research found that the average diameter of the fibers in the three-dimensional fiber network carrier affects the specific surface area and mechanical strength of the network. When the average diameter of the fibers in the three-dimensional fiber network carrier is further selected to be within the above range, the overall performance of the obtained electrochemical device is better.

[0077] In one embodiment, the raw material of the three-dimensional fiber network carrier includes at least one of polyacrylonitrile (PAN), polyvinylidene fluoride (PVDF), polyvinylidene fluoride-hexafluoropropylene (PVDF-HFP), and polyimide (PI).

[0078] This study found that the raw materials of the three-dimensional fiber network carrier affect its electronic and ionic conductivity, as well as its mechanical strength and stability. When the raw materials are of the above types, the overall performance of the resulting electrochemical device is better.

[0079] In one embodiment, the preparation method of the electrode-electrolyte integrated material includes the following steps: S1: Dissolve the raw materials of the three-dimensional fiber network carrier in N,N-dimethylformamide or acetone to prepare a spinning solution with a concentration of 8-12 wt.%, and stir at 60±5℃ for 10-14 h until completely dissolved. Disperse lithiophilic particles with an average particle size of 20-500 nm in ethanol to prepare a suspension with a mass concentration of 1-20%.

[0080] S2: The spinning solution is injected into an electrospinning apparatus to obtain a three-dimensional fiber network carrier with a thickness of 20-150 μm through electrospinning. Then, the spinning solution is switched, and a suspension containing lithiophilic particles is sprayed onto the surface of the three-dimensional fiber network carrier. Without changing the receiving device, an electrolyte layer carrier with a thickness of 10-100 μm is prepared on the three-dimensional fiber network carrier by electrospinning, resulting in a fiber aggregate. Finally, the obtained fiber aggregate is pre-carbonized at 250±10℃ for 1.5-2.5 h.

[0081] S3: In an argon-protected glove box, a sheet of metallic lithium is placed over the negative electrode side of the pre-carbonized fiber assembly. The temperature is controlled at 220±10℃ for 1-30 minutes, allowing the molten lithium to penetrate and composite into the fiber network of the pre-carbonized fiber assembly under capillary force, and react in situ with lithium-philic nanoparticles to form an alloy. After cooling, a negative electrode active layer and an interface transition layer are formed, resulting in a fiber composite.

[0082] S4: Polyethylene oxide (PEO) and lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) are dissolved in acetonitrile to prepare a solution with a mass concentration of 5-10%, and stirred until completely dissolved. The solution is then poured onto the electrolyte carrier side of the fiber composite and allowed to stand at room temperature (20-30℃) for 4-8 hours to allow the solution to fully wet the pores. Subsequently, it is dried in a vacuum drying oven at 60±5℃ for 20-28 hours to completely remove the solvent, forming a solid electrolyte layer filled with PEO-LiTFSI, ultimately obtaining the electrode-electrolyte integrated material.

[0083] In some embodiments, the electrospinning process parameters in step S2 are: voltage 18-30kV, injection speed 0.5-2mL / h, spinning distance 15-20cm, roller speed 50-3000rpm, ambient temperature 25-35℃, and relative humidity 40-75%.

[0084] It should be noted that the thickness of the negative electrode active layer can be changed by controlling the volume of the spinning solution of the negative electrode active layer carrier during the preparation process. For example, by increasing the volume of the spinning solution of the negative electrode active layer carrier, the thickness of the negative electrode active layer will increase.

[0085] It should be noted that the thickness of the solid electrolyte layer can be changed by controlling the volume of the electrolyte layer carrier spinning solution during the preparation process. For example, by increasing the volume of the electrolyte layer carrier spinning solution, the thickness of the solid electrolyte layer will increase.

[0086] It should be noted that by controlling the average particle size of the lithiophilic particulate raw material during the preparation process, the average particle size of the lithiophilic nanoparticles in the product can be changed. For example, by increasing the average particle size of the raw material, the average particle size of the lithiophilic nanoparticles in the product will increase.

[0087] It should be noted that the mass percentage of lithiophilic nanoparticles can be changed by controlling the concentration of lithiophilic nanoparticles or the volume of the suspension during the preparation process. For example, increasing the volume of lithiophilic nanoparticles or the suspension will increase the mass percentage of lithiophilic nanoparticles.

[0088] It should be noted that the mass percentage of polyethylene oxide can be changed by controlling the concentration of the solid electrolyte or the amount of casting during the preparation process. For example, by increasing the concentration of the solid electrolyte or the amount of casting, the mass percentage of polyethylene oxide will increase.

[0089] It should be noted that the mass ratio of lithium bis(trifluoromethanesulfonyl)imide to polyethylene oxide can be changed by controlling the amount of lithium bis(trifluoromethanesulfonyl)imide added during the preparation process. For example, by increasing the amount of lithium bis(trifluoromethanesulfonyl)imide added, the mass ratio of lithium bis(trifluoromethanesulfonyl)imide to polyethylene oxide will increase.

[0090] It should be noted that the porosity of the electrode-electrolyte integrated material can be changed by controlling the concentration of the spinning solution during the preparation process. For example, by increasing the concentration of the spinning solution, the porosity of the electrode-electrolyte integrated material will increase.

[0091] It should be noted that the average fiber diameter in the three-dimensional fiber network carrier can be changed by controlling the electrospinning voltage or flow rate during the preparation process. For example, by reducing the electrospinning voltage or increasing the flow rate, the average fiber diameter in the three-dimensional fiber network carrier will increase.

[0092] A second aspect of this application provides an electrochemical device comprising the electrode-electrolyte integrated material described in this application.

[0093] In one embodiment, the electrochemical device further includes a positive electrode sheet, the positive electrode sheet including a positive current collector and a positive active material layer disposed on at least one side of the positive current collector, the positive active material layer including a positive active material, a positive conductive agent, and a positive binder.

[0094] This application does not have any special requirements for the selection of the positive electrode active material; conventionally available positive electrode active materials in the art can be used. For example, the positive electrode active material may be selected from LiCoO2, LiNiO2, or LiNi. x Mn y O2, Li 1+z Ni x Mn y Co 1-x- y O2, LiNi x Co y Al z The group consisting of O2, LiV2O5, LiTiS2, LiMoS2, LiMnO2, LiCrO2, LiMn2O4, Li2MnO3, LiFeO2, LiFePO4, LiMnPO4, and combinations thereof, wherein each x is independently 0.2 to 0.9; each y is independently 0.1 to 0.45; and each z is independently 0 to 0.2. The positive electrode active material of this application is not limited to the above-mentioned materials, but also includes other materials that can be used as positive electrode active materials.

[0095] Alternatively, the positive electrode active material can be selected from LiCoO2, LiNiO2, or LiNi. x Mn y O2, Li 1+z NixMnyCo 1-x-y O2, LiNi x Co y Al z The group consisting of O2, LiV2O5, LiTiS2, LiMoS2, LiMnO2, LiCrO2, LiMn2O4, LiFeO2, LiFePO4 and combinations thereof, wherein each x is independently 0.4 to 0.6; each y is independently 0.2 to 0.4; and each z is independently 0 to 0.1.

[0096] Or the positive electrode active material is Li 1+x Ni a Mn b Co c Al (1-a-b-c) O2; where -0.2≤x≤0.2, 0≤a<1, 0≤b<1, 0≤c<1 and a+b+c≤1.

[0097] Or the positive electrode active material is Li 1+x Ni a Mn b Co c Al (1-a-b-c)O2, where 0.33≤a≤0.92, 0.33≤a≤0.9, 0.33≤a≤0.8, 0.5≤a≤0.92, 0.5≤a≤0.9, 0.5≤a≤0.8, 0.6≤a≤0.92 or 0.6≤a≤0.9; 0≤b≤0.5, 0≤b≤0.3, 0.1≤b≤0.5, 0.1≤b≤0.4, 0.1≤b≤0.3, 0.1≤b≤0.2 or 0.2≤b≤0.5; 0≤c≤0.5, 0≤c≤0.3, 0.1≤c≤0.5, 0.1≤c≤0.4, 0.1≤c≤0.3, 0.1≤c≤0.2 or 0.2≤c≤0.5.

[0098] In some embodiments, the positive electrode active material is doped with a dopant selected from the group consisting of Fe, Ni, Mn, Al, Mg, Zn, Ti, La, Ce, Sn, Zr, Ru, Si, Ge, and combinations thereof. In some embodiments, the dopant is not Fe, Ni, Mn, Mg, Zn, Ti, La, Ce, Ru, Si, or Ge. In some embodiments, the dopant is not Al, Sn, or Zr.

[0099] In some embodiments, the positive electrode active material may include LiNi. 0.33 Mn 0.33 Co 0.33 O2, LiNiO2, LiNi 0.4 Mn 0.4 Co 0.2 O2, LiNi 0.5 Mn 0.3 Co 0.2 O2, LiNi 0.6 Mn 0.2 Co 0.2 O2, LiNi 0.7 Mn 0.15 Co 0.15 O2, LiNi 0.8 Mn 0.1 Co 0.1 O2, LiNi 0.92 Mn 0.04 Co 0.04 O2, LiNi 0.8 Co 0.15 Al 0.05 At least one of O2.

[0100] This application does not have specific requirements for the selection of the positive electrode binder; conventionally available positive electrode binders in the art can be used. Exemplarily, the positive electrode binder may be at least one of the following: polyvinylidene fluoride (PVDF), poly(vinylidene fluoride)-hexafluoropropylene (PVDF-HFP), polytetrafluoroethylene (PTFE), vinylidene fluoride-tetrafluoroethylene-propylene terpolymer, vinylidene fluoride-hexafluoropropylene-tetrafluoroethylene terpolymer, tetrafluoroethylene-hexafluoropropylene copolymer, fluorinated acrylate resin, polyacrylic acid, polyacrylonitrile, polyimide, polyurethane, polyvinyl butyral, polyvinylpyrrolidone (PVP), acrylic acid-acrylonitrile-acrylamide copolymer, and acrylic acid-acrylonitrile-acrylate copolymer. The positive electrode binder in this application is not limited to the above materials and also includes other materials that can be used as battery positive electrode binders.

[0101] This application does not have any special requirements for the selection of the positive electrode conductive agent; conventionally available positive electrode conductive agents in the art can be used. For example, the positive electrode conductive agent may be at least one of carbon, carbon black, graphite, expanded graphite, graphene, graphene nanosheets, superconducting carbon, acetylene black, carbon black, Ketjen black, carbon dots, carbon fibers, carbon nanofibers, graphitized carbon sheets, carbon nanotubes, carbon nanotubes, activated carbon, and mesoporous carbon. The positive electrode conductive agent in this application is not limited to the above materials and also includes other materials that can be used as positive electrode conductive agents in batteries.

[0102] A third aspect of this application provides an electrical device, which includes the electrochemical device described in this application.

[0103] Example 1 This application provides an integrated electrode-electrolyte material and a solid-state battery. The preparation method of the integrated electrode-electrolyte material and the solid-state battery includes the following steps: (1) Preparation of integrated electrode-electrolyte materials S1. Dissolve 12 wt.% of polyimide (PI) in N,N-dimethylformamide and stir at 60°C for 12 h until completely dissolved to obtain PI spinning solution. Disperse silver nanoparticles with an average particle size of 100 nm in ethanol to prepare a suspension with a concentration of 5 wt.% to obtain a lithiophilic particle suspension. S2. The PI spinning solution was injected into an electrospinning apparatus to obtain a 100 μm thick three-dimensional negative electrode carrier (electrospinning parameters: voltage 20 kV, injection rate 0.8 mL / h, spinning distance 15 cm, roller speed 500 rpm, ambient temperature 35 °C, relative humidity 45%). Then, a lithiophilic particle suspension was switched and sprayed onto the surface of the three-dimensional negative electrode carrier. Without changing the receiving device, an electrolyte layer carrier with a thickness of 50 μm was prepared on the three-dimensional negative electrode carrier (electrospinning parameters: voltage 20 kV, injection rate 0.8 mL / h, spinning distance 15 cm, roller speed 500 rpm, ambient temperature 35 °C, relative humidity 45%). Finally, the resulting fiber aggregate was pre-carbonized at 250 °C for 2 h. S3. The obtained fiber assembly is punched into circular pieces with a diameter of 19 mm. In an argon-protected glove box, a sheet of metallic lithium is placed on the side of the three-dimensional fiber network carrier containing gradient silver nanoparticles. The temperature is controlled at 220℃ for 10 min, allowing the molten lithium to penetrate and composite into the negative electrode carrier fiber network under the drive of capillary force, and react with the silver nanoparticles in situ to form an alloy. After cooling, a negative electrode active layer and an interface transition layer are formed. S4. Polyethylene oxide and lithium bis(trifluoromethanesulfonyl)imide are dissolved in acetonitrile at a mass ratio of 1:4 to prepare a 5 wt.% solution, which is then stirred until completely dissolved. The solution is then poured onto the other side of the material composited with lithium metal and allowed to stand at room temperature (25°C) for 6 hours to allow the solution to fully wet the pores. Subsequently, it is dried in a vacuum drying oven at 60°C for 24 hours to completely remove the solvent, forming a solid electrolyte layer filled with PEO-LiTFSI, thus obtaining the electrode-electrolyte integrated material.

[0104] (2) Preparation of solid-state batteries S1. Lithium iron phosphate active material, conductive carbon black and polyvinylidene fluoride binder are mixed in N-methylpyrrolidone solvent at a mass ratio of 92:4:4 to form a uniform slurry, which is then coated onto an aluminum foil current collector. After being vacuum dried at 120°C for 12 hours, it is cut into a disc with a diameter of 14 mm to serve as the positive electrode of the battery. S2. In a glove box filled with argon atmosphere (H2O≤0.1ppm, O2≤0.1ppm), assemble the cells using a 2032 type button cell mold. Using the aforementioned integrated electrode-electrolyte material as the integrated separator-negative electrode assembly, and lithium iron phosphate electrode sheets as the positive electrode, sequentially place them into the mold to fabricate an all-solid-state battery with lithium iron phosphate as the positive electrode.

[0105] Examples 2-5 This application provides an integrated electrode-electrolyte material and a solid-state battery. The difference between the preparation method of the integrated electrode-electrolyte material and the solid-state battery and that of Example 1 is that the thickness of the negative electrode active layer and the solid electrolyte layer are changed to achieve the parameters in Table 1.

[0106] Examples 6-7 This application provides an integrated electrode-electrolyte material and a solid-state battery. The difference between the preparation method of the integrated electrode-electrolyte material and the solid-state battery in Example 1 is that the average particle size of the silver nanoparticles is changed to achieve the parameters in Table 1.

[0107] Examples 8-9 This application provides an integrated electrode-electrolyte material and a solid-state battery. The difference between the preparation method of the integrated electrode-electrolyte material and the solid-state battery and that of Example 1 is that the type of lithium-loving nanoparticles is changed to achieve the parameters in Table 1.

[0108] Examples 10-11 This application provides an integrated electrode-electrolyte material and a solid-state battery. The difference between the preparation method of the integrated electrode-electrolyte material and the solid-state battery and that of Example 1 is that the amount of lithiophilic nanoparticles added is changed to change the mass percentage of lithiophilic nanoparticles to achieve the parameters in Table 1.

[0109] Examples 12-13 This application provides an integrated electrode-electrolyte material and a solid-state battery. The preparation method of the integrated electrode-electrolyte material and the solid-state battery differs from that of Example 1 in that the amount of polyethylene oxide added is changed to change the mass percentage of polyethylene oxide based on the mass of the three-dimensional fiber network carrier, thereby achieving the parameters in Table 1.

[0110] Examples 14-15 This application provides an integrated electrode-electrolyte material and a solid-state battery. The preparation method of the integrated electrode-electrolyte material and the solid-state battery differs from that of Example 1 in that the amount of lithium bis(trifluoromethanesulfonyl)imide and polyethylene oxide added is changed to change their mass ratio to achieve the parameters in Table 1.

[0111] Examples 16-17 This application provides an integrated electrode-electrolyte material and a solid-state battery. The difference between the preparation method of the integrated electrode-electrolyte material and the solid-state battery and that of Example 1 is that the electrospinning parameters are changed to achieve the change in the average fiber diameter and porosity in the three-dimensional fiber network carrier, thus achieving the parameters in Table 1.

[0112] Example 18 This application provides an integrated electrode-electrolyte material and a solid-state battery. The difference between the preparation method of the integrated electrode-electrolyte material and the solid-state battery and that of Example 1 is that the raw materials of the three-dimensional fiber network carrier are changed to achieve the parameters in Table 1.

[0113] Example 19 This application provides an integrated electrode-electrolyte material and a solid-state battery. The preparation method of the integrated electrode-electrolyte material and the solid-state battery differs from that of Example 1 in that the electrolyte composition is changed (specifically, lithium bis(trifluoromethanesulfonyl)imide and polyvinylidene fluoride are dissolved in dimethylformamide at a mass ratio of 1:1.5) to achieve the parameters in Table 1.

[0114] Comparative Examples 1-2 This application provides an electrode-electrolyte integrated material and a solid-state battery in a comparative example. The difference between the preparation method of the electrode-electrolyte integrated material and the solid-state battery and that of Example 1 is that the thickness ratio of the negative electrode active layer to the solid electrolyte layer is changed to achieve the parameters in Table 1.

[0115] Comparative Example 3 This application provides an electrode-electrolyte integrated material and a solid-state battery in a comparative example. The preparation method of the electrode-electrolyte integrated material and the solid-state battery differs from that of Example 1 in that lithium-loving nanoparticles are not added to achieve the parameters in Table 1.

[0116] Comparative Example 4 This application provides an electrode-electrolyte integrated material and a solid-state battery as a comparative example. The difference between the preparation method of the electrode-electrolyte integrated material and the solid-state battery and that of Example 1 is that aluminum oxide is used instead of silver to achieve the parameters in Table 1.

[0117] The following parameters are listed in Table 1: thickness ratio H of negative electrode active layer to solid electrolyte layer, thickness h1 of negative electrode active layer, thickness h2 of solid electrolyte layer, average particle size D of lithium-loving nanoparticles, type of lithium-loving nanoparticles, mass percentage W1 of lithium-loving nanoparticles, mass percentage W2 of polyethylene oxide based on the mass of three-dimensional fiber network carrier, mass ratio M of lithium bis(trifluoromethanesulfonylimide) to polyethylene oxide, porosity P of electrode-electrolyte integrated material, average fiber diameter d in three-dimensional fiber network carrier, and raw materials of three-dimensional fiber network carrier. Table 1 The performance tests of the solid-state batteries obtained in the examples and comparative examples include the following aspects: 1. Rate Performance: After the assembled solid-state battery was placed at 60°C for 2 hours to reach thermal equilibrium, it was tested using the LAND battery testing system. First, it underwent three charge-discharge cycles at 0.1C for activation. Then, under the same temperature conditions, constant current charge-discharge tests were performed at rates of 0.2C, 0.5C, 1C, and 2C, respectively, and the discharge specific capacity at 2C was recorded. Each rate was cycled 5 times, with a voltage range of 2.5-3.8V. Finally, it was cycled again at 0.2C for 5 cycles, and the capacity recovery rate was calculated to evaluate the battery's performance and structural stability at different discharge rates. 2. Cycling performance: The activated solid-state battery was subjected to constant current charge-discharge cycle testing at 0.5C in an environment of 60°C, with a voltage range of 2.5-3.8V. The discharge specific capacity of the battery at the 100th cycle was recorded, and the capacity retention rate was calculated to evaluate the capacity decay and interface stability of the battery during long-term cycling. The results are shown in Table 2; Table 2 As shown in Table 2, when the technical solution provided in this application is adopted, the resulting solid-state battery exhibits excellent rate performance and cycle performance. Specifically, after 100 cycles at 0.5C, the capacity retention is above 85.1%, and the discharge specific capacity is above 142.8 mAh / g. Regarding rate performance, the discharge capacity of each embodiment at a high 2C rate is above 121.4 mAh / g, and the capacity recovery rate when returning to 0.2C after the rate test is above 94.7%. In contrast, Comparative Examples 1-4, due to key parameters exceeding the scope of this application or the lack of a core interface transition layer design, show significantly inferior cycle performance (capacity retention below 82.1%) and rate performance (2C capacity retention below 88.5%) compared to the embodiments of this application. This indicates that this application effectively improves the overall electrochemical performance of solid-state batteries by optimizing the integrated negative electrode / electrolyte structure and its interface characteristics.

[0118] Finally, it should be noted that the above embodiments are used to illustrate the technical solutions of this application and not to limit the scope of protection of this application. Although this application has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of this application without departing from the substance and scope of the technical solutions of this application.

Claims

1. An integrated electrode-electrolyte material, characterized in that, It includes a three-dimensional fiber network carrier, and a negative electrode active layer, an interface transition layer and a solid electrolyte layer sequentially disposed inside the carrier; The thickness ratio of the negative electrode active layer to the solid electrolyte layer is 1:(0.2-1.5). The interface transition layer comprises lithium-loving particles.

2. The electrode-electrolyte integrated material according to claim 1, characterized in that, Satisfy at least one of the following: (1) The thickness of the negative electrode active layer is 20-150 μm; (2) The thickness of the solid electrolyte layer is 10-100 μm; (3) The average particle size of the lithiophilic particles is 20-500 nm; (4) The lithiophilic particles include at least one of tin, silver, and tin fluoride.

3. The electrode-electrolyte integrated material according to claim 1, characterized in that, The negative electrode active layer comprises lithium metal.

4. The electrode-electrolyte integrated material according to claim 3, characterized in that, The mass percentage of the lithiophilic particles is 0.5-15% based on the mass of the lithium.

5. The electrode-electrolyte integrated material according to claim 1, characterized in that, The solid electrolyte layer includes an electrolyte comprising polyethylene oxide and lithium bis(trifluoromethanesulfonyl)imide.

6. The electrode-electrolyte integrated material according to claim 5, characterized in that, The polyethylene oxide comprises 20-80% by mass of the three-dimensional fiber network carrier. And / or, the mass ratio of lithium bis(trifluoromethanesulfonyl)imide to polyethylene oxide is 1:(2-8).

7. The electrode-electrolyte integrated material according to claim 1, characterized in that, The porosity of the electrode-electrolyte integrated material is 40-85%; And / or, the average diameter of the fibers in the three-dimensional fiber network carrier is 100-2000 nm.

8. The electrode-electrolyte integrated material according to claim 1, characterized in that, The raw materials for the three-dimensional fiber network carrier include at least one of polyacrylonitrile, polyvinylidene fluoride, polyvinylidene fluoride-hexafluoropropylene, and polyimide.

9. An electrochemical device, characterized in that, The electrochemical device includes the electrode-electrolyte integrated material as described in any one of claims 1-8.

10. An electrical appliance, characterized in that, Includes the electrochemical device as described in claim 9.

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