Solid-state battery and method of manufacturing the same

Abstract

This invention discloses a solid-state battery and its fabrication method, relating to the field of lithium battery technology. The solid-state battery includes: a solid electrolyte layer, a positive electrode and a negative electrode disposed on opposite sides of the solid electrolyte layer, and an organometallic gel layer disposed between the negative electrode and the solid electrolyte layer. The organometallic gel layer is in direct contact with the solid electrolyte layer and the negative electrode. After an initial potential is applied to the solid-state battery, the organometallic gel layer transforms into an interface layer containing an inorganic lithium alloy network structure, which is in direct contact with the solid electrolyte layer and the negative electrode. This inorganic lithium alloy network structure can improve the ionic conductivity and mechanical strength of the solid-state battery.

Description

Technical Field

[0001] This invention relates to the field of lithium battery technology, and in particular to a solid-state battery and its preparation method. Background Technology

[0002] For solid-state batteries, the interface performance between the solid electrolyte and the negative electrode is a key factor affecting battery performance. An ideal interface requires, on the one hand, good electrical contact with both the solid electrolyte and the negative electrode; on the other hand, this interface should possess good ionic conductivity, electronic insulation, chemical stability, and mechanical robustness. Although current research has used gel polymer electrolytes to improve the interface between the solid electrolyte and the negative electrode, gel polymer electrolytes suffer from low mechanical strength and limited ionic conductivity. Summary of the Invention

[0003] In view of this, embodiments of the present invention provide a solid-state battery and a method for preparing the same. The solid-state battery introduces an organometallic gel layer between the solid electrolyte layer and the negative electrode. This organometallic gel layer can be transformed into an interface layer containing an inorganic lithium alloy network structure during the initial application of a potential to the solid-state battery. On the one hand, the inorganic lithium alloy network structure can provide sufficient lithium source for the solid-state battery and improve the ionic conductivity of the solid-state battery. On the other hand, the inorganic lithium alloy network structure has strong stability and support, which helps to improve the mechanical strength of the solid-state battery.

[0004] To achieve the above objectives, in a first aspect, according to an embodiment of the present invention, a solid-state battery is provided, comprising: a solid electrolyte layer, a positive electrode and a negative electrode disposed on opposite sides of the solid electrolyte layer, and an organometallic gel layer disposed between the negative electrode and the solid electrolyte layer, wherein, The organometallic gel layer is in direct contact with the solid electrolyte layer and the negative electrode; After a potential is first applied to the solid-state battery, the organometallic gel layer is transformed into an interface layer comprising an inorganic lithium alloy network structure, which is in direct contact with the solid electrolyte layer and the negative electrode.

[0005] Optionally, the organometallic gel layer is a single layer or a multilayer structure.

[0006] Optionally, the organometallic gel layer is a single-layer structure, formed by polymerization of an organic precursor mixture containing a decomposable lithium salt and a lithium-bearing organic monomer induced by a polymerization initiator.

[0007] Optionally, the organometallic gel layer is a multilayer structure, wherein the layer closest to the negative electrode is formed by polymerization of an organic precursor mixture containing a decomposable lithium salt induced by a polymerization initiator, and the layer closest to the solid electrolyte layer is formed by polymerization of an organic precursor mixture containing a decomposable lithium salt and an organic monomer containing a lithium-philic atom induced by a polymerization initiator.

[0008] Optionally, the decomposable lithium salt comprises at least one compound capable of decomposing into lithium fluoride, lithium borate, lithium oxide, or lithium phosphate.

[0009] Optionally, the lithium-containing organic monomer includes one or more of the following: vinylsilane, silicon (meth)acrylate, 3-(trimethoxysilyl)propylacrylate, and germanium diacrylate.

[0010] Optionally, the polymerization initiator is a photoinitiator or a thermal initiator.

[0011] Optionally, the decomposable lithium salt is a dianion system containing boron and fluorine atoms.

[0012] Optionally, the decomposable lithium salt includes lithium difluoro(oxalate)borate, lithium bis(oxalate)borate, and lithium pyrophosphate; or, the decomposable lithium salt includes lithium bis(fluorosulfonyl)imide and lithium tetrafluoroborate.

[0013] Optionally, the thickness of the inorganic lithium alloy network structure is 1 μm to 2 μm.

[0014] Optionally, the initial potential applied to the solid-state battery is 4.4V to 5V.

[0015] Secondly, embodiments of the present invention provide a solid-state battery, comprising: a solid electrolyte layer, a positive electrode, a negative electrode, and an interface layer, wherein... The positive electrode and the negative electrode are respectively disposed on both sides of the solid electrolyte layer; The interface layer is disposed between the negative electrode and the solid electrolyte layer and is in direct contact with both the negative electrode and the solid electrolyte layer; The interface layer comprises an inorganic lithium alloy network structure, which is in direct contact with the solid electrolyte layer and the negative electrode.

[0016] Optionally, the inorganic lithium alloy network structure includes lithium atoms and lithiumophile atoms.

[0017] Optionally, the lithiumophile atom includes one or more of Si, Ge, Sn, and Al.

[0018] Optionally, the solid-state battery further includes: a layer containing LiF and LiB located between the interface layer and the solid electrolyte layer.x O γ The conductive layer, where x and γ are non-zero positive numbers.

[0019] Thirdly, embodiments of the present invention provide a method for preparing a solid-state battery, comprising: Step 1: Coat the main surface of the negative electrode and / or the main surface of the solid electrolyte layer with an organic precursor mixture, wherein the organic precursor mixture comprises: a polymerization initiator, a decomposable lithium salt, and an organic monomer containing lithium-philic atoms. Step 2: Assemble the positive electrode, the negative electrode, and the solid electrolyte layer, wherein the organic precursor mixture is located between the negative electrode and the solid electrolyte layer; Step 3: Expose the assembled structure to light or heat to polymerize the organic precursor mixture into an organometallic gel layer.

[0020] Optionally, in the structure assembled in step 2, the thickness of the organic precursor mixture coated between the negative electrode and the solid electrolyte layer is 2 μm to 4 μm.

[0021] Optionally, the organic precursor mixture comprises: 46wt% to 52wt% of a lithium-containing organic monomer, 47wt% to 51wt% of a decomposable lithium salt, and 1wt% to 3wt% of a polymerization initiator.

[0022] Optionally, the preparation method further includes: step 4, applying a potential to the solid-state battery formed in step 3, so that the organometallic gel layer is transformed into an interface layer containing an inorganic lithium alloy network structure, wherein the inorganic lithium alloy network structure is in direct contact with the solid electrolyte layer and the negative electrode.

[0023] Optionally, step 3 includes: for cases where the polymerization initiator included in the organic precursor mixture is a photoinitiator, irradiating the assembled structure with long-wavelength ultraviolet light with a wavelength of 315nm~400nm.

[0024] Optionally, step 3 includes: if the polymerization initiator included in the organic precursor mixture is a thermal initiator, hot-pressing the assembled structure at a temperature of 50°C to 70°C.

[0025] One embodiment of the above invention has the following advantages or beneficial effects: The solid-state battery provided by the present invention introduces an organometallic gel layer between the solid electrolyte layer and the negative electrode. The organometallic gel layer is in direct contact with the solid electrolyte layer and the negative electrode. During the initial application of a potential to the solid-state battery, the organometallic gel layer can be transformed into an interface layer containing an inorganic lithium alloy network structure. The inorganic lithium alloy network structure is in direct contact with the solid electrolyte layer and the negative electrode. On the one hand, the inorganic lithium alloy network structure can provide sufficient lithium source for the solid-state battery and improve the ionic conductivity of the solid-state battery. On the other hand, the inorganic lithium alloy network structure has strong stability and support, which helps to improve the mechanical strength of the solid-state battery.

[0026] The further effects of the aforementioned unconventional alternative methods will be explained below in conjunction with specific implementation methods. Attached Figure Description

[0027] The accompanying drawings are provided to better understand the invention and are not intended to unduly limit the scope of the invention. Wherein: Figure 1 This is a cross-sectional structural diagram of a first structure of a solid-state battery according to an embodiment of the present invention. Figure 2 This is a cross-sectional structural diagram of a second structure of a solid-state battery according to an embodiment of the present invention; Figure 3 This is a schematic diagram of the main process of a solid-state battery preparation method according to an embodiment of the present invention; Figure 4 This is a schematic diagram showing the structural changes corresponding to each step of the solid-state battery preparation method according to an embodiment of the present invention.

[0028] Explanation of reference numerals in the attached figures: 10-Solid electrolyte layer; 20-Positive electrode; 30-Negative electrode; 40-Organometallic gel layer; 50-Interface layer; 51-Inorganic lithium alloy network structure. Detailed Implementation

[0029] As described in the background section, the interfacial properties between the negative electrode and the solid electrolyte directly affect the performance of solid-state batteries. Studies have found that an interface rich in inorganic components such as LiF and Li₂O at the negative electrode-solid electrolyte interface can effectively improve the ionic conductivity and chemical stability between the two. These inorganic components, such as LiF and Li₂O, can be formed by the decomposition of specific electrolyte salts or additives. However, controlling this decomposition process to create a perfect, uniform interface in an all-solid-state system remains a significant challenge.

[0030] To address the aforementioned issues at the interface between the solid electrolyte and the negative electrode in solid-state batteries, this invention provides a novel solid-state battery structure and its fabrication method. This solid-state battery enables the formation of an inorganic lithium alloy network structure between the solid electrolyte layer 10 and the negative electrode 30. This inorganic lithium alloy network structure not only provides sufficient Li ions for the solid-state battery but also effectively improves its mechanical strength and ionic conductivity.

[0031] The following description, in conjunction with the accompanying drawings, illustrates exemplary embodiments of the present invention, including various details to aid understanding. These details should be considered merely exemplary. Therefore, those skilled in the art will recognize that various changes and modifications can be made to the embodiments described herein without departing from the scope and spirit of the invention. Similarly, for clarity and brevity, descriptions of well-known functions and structures are omitted in the following description.

[0032] It should be noted that, unless otherwise specified, the embodiments of the present invention and the technical features thereof can be combined with each other.

[0033] Specifically, this invention provides a solid-state battery. Figure 1 A cross-sectional structural diagram of a solid-state battery provided in an embodiment of the present invention is shown. Figure 1 As shown, the solid-state battery may include: a solid electrolyte layer 10, a positive electrode 20 and a negative electrode 30 disposed on both sides of the solid electrolyte layer 10, and an organometallic gel layer 40 disposed between the negative electrode 30 and the solid electrolyte layer 10.

[0034] In this process, the organometallic gel layer 40 is in direct contact with the solid electrolyte layer 10 and the negative electrode 30. After the first potential is applied to the solid-state battery, the organometallic gel layer 40 transforms into an interface layer 50 containing an inorganic lithium alloy network structure 51. The inorganic lithium alloy network structure 51 is in direct contact with the solid electrolyte layer 10 and the negative electrode 30. Thus, after the first potential is applied to the solid-state battery, the desired result is obtained. Figure 2 The structure of the solid-state battery is shown.

[0035] The initial application of potential to a solid-state battery can occur after the battery is installed in an electrical device (such as a vehicle or smart device) and the device is powered on for the first time. Alternatively, the initial application of potential can also occur before the battery is installed in the electrical device (such as a vehicle or smart device), during the final step of the solid-state battery production line, or during the solid-state battery quality inspection process.

[0036] In other words, the solid-state battery provided in this embodiment of the invention forms an interface layer 50 containing an inorganic lithium alloy network structure 51 through an organometallic gel layer 40, thereby achieving in-situ generation of an inorganic composite interface between the negative electrode 30 and the solid electrolyte layer 10. Compared with organic materials, the inorganic composite interface has better chemical and mechanical stability and can more effectively suppress side reactions, thereby achieving higher coulombic efficiency and longer cycle life.

[0037] Therefore, the solid-state battery provided in this embodiment of the invention introduces an organometallic gel layer 40 between the solid electrolyte layer 10 and the negative electrode 30. The organometallic gel layer 40 is in direct contact with the solid electrolyte layer 10 and the negative electrode 30. During the initial application of a potential to the solid-state battery, the organometallic gel layer 40 can be transformed into an interface layer 50 containing an inorganic lithium alloy network structure 51. The inorganic lithium alloy network structure 51 is in direct contact with the solid electrolyte layer 10 and the negative electrode 30. On the one hand, the inorganic lithium alloy network structure 51 can provide sufficient lithium source for the solid-state battery and improve the ionic conductivity of the solid-state battery. On the other hand, the inorganic lithium alloy network structure 51 has strong stability and support, which helps to improve the mechanical strength of the solid-state battery.

[0038] Furthermore, the solid-state battery provided in this embodiment of the invention can effectively ensure a gapless and tight contact between the negative electrode 30 and the solid electrolyte layer 10 by generating an inorganic composite interface in situ between the negative electrode 30 and the solid electrolyte layer 10. The inorganic lithium alloy network structure 51 formed by the conversion can be firmly "riveted" to the surface of the negative electrode 30 and the surface of the solid electrolyte layer 10, fundamentally solving the problem of poor contact at the solid-solid interface.

[0039] The organometallic gel layer 40 can be a single layer or a multilayer structure.

[0040] Specifically, the organometallic gel layer 40 is a single-layer structure formed by the polymerization of an organic precursor mixture containing a decomposable lithium salt and a lithium-bearing organic monomer induced by a polymerization initiator. The decomposable lithium salt provides a sufficient lithium source for the formed inorganic lithium alloy network structure 51 and can improve the ionic conductivity and mechanical strength of the formed inorganic lithium alloy network structure 51. The lithium-bearing organic monomer can provide lithium-bearing atoms for the inorganic lithium alloy network structure 51, which can serve as a conductive support for the formation of the inorganic lithium alloy network structure 51; on the other hand, the lithium-bearing atoms can provide strong mechanical adhesion for the negative electrode 30.

[0041] Regarding the multilayer structure of the organometallic gel layer 40, the layer closest to the negative electrode 30 is formed by polymerization of an organic precursor mixture containing a decomposable lithium salt induced by a polymerization initiator. The layer closest to the solid electrolyte layer 10 is formed by polymerization of an organic precursor mixture containing a decomposable lithium salt and a lithium-bearing organic monomer induced by a polymerization initiator. That is, the layer closest to the solid electrolyte layer 10 of the organometallic gel layer 40 may not contain a lithium-bearing organic monomer. The organometallic gel layer 40 formed by polymerization of this organic precursor mixture containing a decomposable lithium salt and a lithium-bearing organic monomer can provide sufficient LiF and LiB. x O γ Where x and γ are non-zero positive numbers, this provides sufficient LiF and LiB. x O γ The interface layer subsequently formed from the organometallic gel layer 40 has better ionic conductivity and electronic insulation.

[0042] The decomposable lithium salt comprises at least one compound capable of decomposing into lithium fluoride, lithium borate, lithium oxide, or lithium phosphate. Preferably, the decomposable lithium salt is a dianionic system containing boron and fluorine atoms. More preferably, the decomposable lithium salt includes lithium difluoro(oxalate)borate, lithium bis(oxalate)borate, and lithium pyrophosphate; or, the decomposable lithium salt includes lithium bis(fluorosulfonyl)imide and lithium tetrafluoroborate. By selecting these decomposable lithium salts, the ionic conductivity and mechanical strength of the formed inorganic lithium alloy network structure 51 can be effectively improved.

[0043] The organic monomers containing lithium-ion atoms include one or more of the following: vinylsilane, silicon (meth)acrylate, 3-(trimethoxysilyl)propylacrylate, and germanium diacrylate. The lithium-ion atom can be a silicon atom or a germanium atom.

[0044] The polymerization initiator can be a photoinitiator or a thermal initiator. For a photoinitiator, under ultraviolet light irradiation, it can polymerize the organic precursor mixture to form an organometallic gel layer 40. For a thermal initiator, it can polymerize the organic precursor mixture to form an organometallic gel layer 40 under heating conditions. The formed organometallic gel layer 40 exhibits non-flowability and conformal properties to ensure that it can stably adhere to the surfaces of the solid electrolyte layer 10 and the negative electrode 30, thus ensuring a tight and gap-free contact between the negative electrode 30 and the organometallic gel layer 40, and also ensuring a tight and gap-free contact between the solid electrolyte layer 10 and the organometallic gel layer 40.

[0045] By controlling the amount of organic monomers containing lithium-loving atoms and the amount of decomposable lithium salts added, the inorganic lithium alloy network structure 51 in the interface layer 50 can form a good and reliable contact with the solid electrolyte layer 10 and the negative electrode 30.

[0046] It is worth noting that the interface layer 50 formed may include not only the inorganic lithium alloy network structure 51, but also solidified organic matter. The solidified organic matter fills the gaps between the inorganic lithium alloy network structures 51, which does not affect the ionic conductivity and mechanical strength of the inorganic lithium alloy network structure 51, and can ensure the integrity of the interface layer 50.

[0047] The thickness of the formed inorganic lithium alloy network structure 51 is generally 1μm to 2μm, for example, the thickness of the inorganic lithium alloy network structure 51 can be 1μm, 1.2μm, 1.5μm, 1.8μm or 2μm, etc. By controlling the thickness of the inorganic lithium alloy network structure 51, the ionic conductivity of the inorganic lithium alloy network structure 51 can be guaranteed, and lithium ions can be avoided from accumulating at the interface.

[0048] The initial potential applied to the solid-state battery can be 4.4V to 5V. For example, the initial potential applied to the solid-state battery can be 4.4V, 4.5V, 4.8V or 5V, etc. By controlling the initial potential applied to the solid-state battery, a reliable inorganic lithium alloy network structure can be effectively formed 51.

[0049] On the other hand, embodiments of the present invention also provide another solid-state battery. Specifically, such as Figure 2 As shown, this alternative solid-state battery may include: a solid electrolyte layer 10, a positive electrode 20, a negative electrode 30, and an interface layer 50. The positive electrode 20 and the negative electrode 30 are disposed on opposite sides of the solid electrolyte layer 10; the interface layer 50 is disposed between the negative electrode 30 and the solid electrolyte layer 10 and is in direct contact with both the negative electrode 30 and the solid electrolyte layer 10; the interface layer 50 includes an inorganic lithium alloy network structure 51, which is in direct contact with the solid electrolyte layer 10 and the negative electrode 30.

[0050] This solid-state battery, by setting an interface layer 50 containing an inorganic lithium alloy network structure 51 between the negative electrode 30 and the solid electrolyte layer 10, on the one hand, the inorganic lithium alloy network structure 51 can provide sufficient lithium source for the solid-state battery and improve the ionic conductivity of the solid-state battery; on the other hand, the inorganic lithium alloy network structure 51 has strong stability and support, which helps to improve the mechanical strength of the solid-state battery.

[0051] More specifically, the inorganic lithium alloy network structure 51 includes lithium atoms and lithiophilic atoms; preferably, the lithiophilic atoms include one or more of Si, Ge, Sn, and Al. For example, the inorganic lithium alloy network structure 51 may include Lix Si, Li x Ge, Li x Sn or Li x Al, etc., can provide a sufficient lithium source for the negative electrode 30, while ensuring the stability and reliability of the inorganic lithium alloy network structure 51.

[0052] Furthermore, the solid-state battery may also include: a layer containing LiF and LiB located between the interface layer 50 and the solid electrolyte layer 10. x O γ A conductive layer, where x and γ are non-zero positive numbers. This conductive layer can provide sufficient LiF and LiB. x O γ It has superior ionic conductivity and electronic insulation.

[0053] Furthermore, embodiments of the present invention provide a method for preparing a solid-state battery. For example... Figure 3 As shown, the method for preparing this solid-state battery may include: Step S301: Coat the organic precursor mixture 40' onto one side of the main surface of the negative electrode 30 and / or one side of the main surface of the solid electrolyte layer 10, wherein the organic precursor mixture includes: a polymerization initiator, a decomposable lithium salt, and an organic monomer containing lithium-philic atoms.

[0054] For example, such as Figure 4 As shown, the organic precursor mixture 40' can be coated on one side of the main surface of the negative electrode 30, or the organic precursor mixture 40' can be coated on one side of the main surface of the solid electrolyte layer 10, or the organic precursor mixture 40' can be coated on both one side of the main surface of the negative electrode 30 and one side of the main surface of the solid electrolyte layer 10.

[0055] The organic precursor mixture 40' generally includes the aforementioned polymerization initiator, decomposable lithium salt, and lithium-containing organic monomer. However, for the technical solution of coating the organic precursor mixture 40' onto one side of the main surface of the negative electrode 30 and the other side of the main surface of the solid electrolyte layer 10, another organic precursor mixture 40' containing a polymerization initiator and a decomposable lithium salt but not lithium-containing organic monomer can also be used. In this case, the organic precursor mixture 40' containing the aforementioned polymerization initiator, decomposable lithium salt, and lithium-containing organic monomer is coated onto one side of the main surface of the negative electrode 30, and the other organic precursor mixture 40' containing a polymerization initiator and a decomposable lithium salt but not lithium-containing organic monomer is coated onto the other side of the main surface of the solid electrolyte layer 10, so that the interface layer 50 near the negative electrode 30 and the conductive layer near the solid electrolyte layer 10 (not shown in the figure) are subsequently formed.

[0056] Step S302: Assemble the positive electrode 20, the negative electrode 30 and the solid electrolyte layer 10, wherein the organic precursor mixture 40' is located between the negative electrode 30 and the solid electrolyte layer 10.

[0057] like Figure 4 As shown, the organic precursor mixture 40' is located between the negative electrode 30 and the solid electrolyte layer 10.

[0058] Step S303: The assembled structure is subjected to light or heat treatment to polymerize the organic precursor mixture 40' into an organometallic gel layer 40.

[0059] like Figure 4 As shown, after phototreatment, the organic precursor mixture 40' polymerizes into an organometallic gel layer 40. The phototreatment can be applied to either the side irradiating the negative electrode 30 or the side furthest from the negative electrode 30.

[0060] It is worth noting that, Figure 3 and Figure 4 The above-described preparation method only illustrates some steps and structural changes. In addition to assembling the positive electrode 20 in step S302, the above preparation method can also provide the positive electrode 20 on the side of the solid electrolyte layer 10 away from the negative electrode 30 after step S301 or after step S303.

[0061] After applying a potential to the solid-state battery prepared in step S303 for the first time, the organometallic gel layer 40 is transformed into an interface layer 50 containing an inorganic lithium alloy network structure 51, which is in direct contact with the solid electrolyte layer 10 and the negative electrode 30.

[0062] The preparation method provided in this invention uses an organometallic gel layer 40 designed specifically for building a perfect interface, without needing to consider long-term stable ion transport function, thus avoiding the performance defects of traditional gel polymer electrolytes.

[0063] The organic precursor mixture may include: 46wt% to 52wt% by mass of a lithium-containing organic monomer, 47wt% to 51wt% by mass of a decomposable lithium salt, and 1wt% to 3wt% by mass of a polymerization initiator. For example, the mass fraction of the lithium-containing organic monomer may be 46wt%, 48wt%, 50wt%, or 52wt%, the mass fraction of the decomposable lithium salt may be 47wt%, 48wt%, 50wt%, or 51wt%, and the mass fraction of the polymerization initiator may be 1wt%, 2wt%, or 3wt%. The lithium-containing organic monomer includes one or more of vinylsilane, silicon (meth)acrylate, 3-(trimethoxysilyl)propylacrylate, and germanium diacrylate. The decomposable lithium salt contains at least one compound capable of decomposing into lithium fluoride, lithium borate, lithium oxide, or lithium phosphate; preferably, the decomposable lithium salt is a dianionic system containing boron and fluorine atoms. More preferably, the decomposable lithium salt includes lithium difluoro(oxalate)borate, lithium bis(oxalate)borate, and lithium pyrophosphate; or, the decomposable lithium salt includes lithium bis(fluorosulfonyl)imide and lithium tetrafluoroborate. By precisely controlling the chemical composition of the precursor (such as the type of organometallic monomer and the ratio of dianionic salts), the properties of the final inorganic interface (such as ionic / electronic conductivity, mechanical modulus, and chemical composition) can be finely engineered to meet the specific requirements of different battery systems.

[0064] More specifically, in the structure assembled in step S302, the thickness of the organic precursor mixture 40' coated between the negative electrode 30 and the solid electrolyte layer 10 is 2 μm to 4 μm. For example, the thickness of the organic precursor mixture 40' can be 2 μm, 2.5 μm, 3 μm, 3.5 μm, or 4 μm, etc. By controlling the thickness of the organic precursor mixture 40', the thickness of the formed interface layer 50 can be effectively controlled.

[0065] Step S303 can be implemented in two specific ways. The first implementation of step S303 may include: if the polymerization initiator in the organic precursor mixture is a photoinitiator, irradiating the assembled structure with long-wavelength ultraviolet light (315nm~400nm). The second implementation of step S303 may include: if the polymerization initiator in the organic precursor mixture is a thermal initiator, hot-pressing the assembled structure at a temperature of 50℃~70℃. This allows for the selection of different curing methods to form the organometallic gel layer 40, depending on whether the polymerization initiator is a photoinitiator or a thermal initiator, while simultaneously forming an integrated structure of the negative electrode 30, the solid electrolyte layer 10, and the organometallic gel layer 40.

[0066] Furthermore, the above preparation method may further include: step S304: applying a potential to the solid-state battery formed in step S303, causing the organometallic gel layer 40 to be transformed into an interface layer 50 containing an inorganic lithium alloy network structure 51, wherein the inorganic lithium alloy network structure 51 is in direct contact with the solid electrolyte layer 10 and the negative electrode 30, thereby obtaining... Figure 2 The solid-state battery shown.

[0067] The following examples illustrate in detail the method for preparing solid-state batteries according to embodiments of the present invention.

[0068] Example 1

[0069] Step A: Prepare a solvent-free precursor liquid, the composition of which is: 50 wt% 3-(trimethoxysilyl)propyl acrylate, 24 wt% lithium difluorooxalate borate (LiDFOB), 24 wt% lithium bis(oxalate)borate (LiBOB), and 2 wt% 2-hydroxy-2-methylphenylacetone (photoinitiator).

[0070] Step B: The solvent-free precursor liquid prepared in step A is used to form a thin film with a thickness of about 2 μm on the surface of the lithium metal negative electrode by a blade coating method. The lithium metal negative electrode with the thin film is assembled with the NCM90 positive electrode and the LLZO electrolyte sheet. Then, the film is irradiated with a 365 nm ultraviolet lamp for 5 minutes in an inert atmosphere glove box to polymerize and solidify the film into an organometallic gel layer.

[0071] Step C: During the initial charging to 4.6V, the organometallic gel layer decomposes. 3-(trimethoxysilyl)propyl acrylate, lithium difluorooxalate borate (LiDFOB), and lithium bis(oxalate)borate (LiBOB) form a lithium-philic Li... x Si alloy network, and LiDFOB and LiBOB decompose into LiF- and LiB-rich compounds. x O γ The inorganic matrix was used. The solid-state battery prepared in Example 1 was tested using existing battery cycle testing methods. After 2000 stable cycles at 1C rate, the solid-state battery maintained a capacity retention of up to 84.8%.

[0072] Example 2

[0073] The main difference between Example 2 and Example 1 is that in step A, 50 wt% 3-(trimethoxysilyl)propyl acrylate is replaced with 50 wt% Germanium diacrylate, and the lithium salt system of 24 wt% lithium difluorooxalate borate (LiDFOB) and 24 wt% lithium bis(oxalate)borate (LiBOB) is replaced with 30 wt% lithium bis(fluorosulfonyl)imide (LiFSI) and 20 wt% lithium tetrafluoroborate (LiBF4). The initiator of 2 wt% 2-hydroxy-2-methylphenylacetone is replaced with 2 wt% benzoyl peroxide (BPO, a thermal initiator). The photocuring in step B is replaced with hot-pressing the assembled structure of the thin-film lithium metal negative electrode, NCM90 positive electrode, and LLZO electrolyte sheet at 60°C for 10 min to complete in-situ polymerization and curing. During the initial charging process in step C, germanium diacrylate is converted into conductive Li. x Ge alloy framework, while LiFSI and LiBF4 decompose to form a matrix mainly composed of LiF and Li2O, i.e., Li is present in the interface layer. x Ge alloy skeleton and located in Li x LiF and Li₂O are bonded to a Ge alloy framework. This interface exhibits extremely high ionic conductivity and mechanical modulus, even at 5 mA·cm⁻¹ in Li||Li symmetric cell tests. - It can cycle stably for more than 1000 hours even at high current densities, and the polarization voltage is less than 50 mV.

[0074] Example 3

[0075] An interface layer comprising an inorganic lithium alloy network structure is formed between the solid electrolyte layer and the lithium negative electrode. Specifically, a first thin film is coated on the side near the lithium negative electrode using a solvent-free precursor liquid prepared in step A of Example 1 to ensure excellent lithium affinity and adhesion. A second thin film is coated on the side of the solid electrolyte layer near the lithium negative electrode using a solvent-free precursor liquid containing 30 wt% lithium bis(fluorosulfonyl)imide (LiFSI), 20 wt% lithium tetrafluoroborate (LiBF4), and a photoinitiator, without organometallic monomers, and then UV-cured. The first thin film forms a first organometallic gel layer, and the second thin film forms a second organometallic gel layer. During the initial charging to 4.6V formation process, the first organometallic gel layer forms containing LiF and LiB. x O γ Li x The Si alloy / inorganic composite network structure, while the second organometallic gel layer is transformed into a structure rich in LiF and LiB. x O γA pure inorganic layer with superior ionic conductivity and electronic insulation. This gradient stacked structure mimics naturally formed interface layers but exhibits superior chemical and mechanical stability. In Li||Cu battery tests, this interface achieved an average coulombic efficiency exceeding 99%, outperforming monolayer precursor systems.

[0076] The specific embodiments described above do not constitute a limitation on the scope of protection of this invention. Those skilled in the art should understand that various modifications, combinations, sub-combinations, and substitutions can occur depending on design requirements and other factors. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this invention should be included within the scope of protection of this invention.

Claims

1. A solid-state battery, characterized in that, include: The solid electrolyte layer (10), the positive electrode (20) and the negative electrode (30) disposed on both sides of the solid electrolyte layer (10), and the organometallic gel layer (40) disposed between the negative electrode (30) and the solid electrolyte layer (10), wherein, The organometallic gel layer (40) is in direct contact with the solid electrolyte layer (10) and the negative electrode (30); After a potential is first applied to the solid-state battery, the organometallic gel layer (40) is transformed into an interface layer (50) containing an inorganic lithium alloy network structure (51) that is in direct contact with the solid electrolyte layer (10) and the negative electrode (30).

2. The solid-state battery according to claim 1, characterized in that, The organometallic gel layer (40) has a single-layer or multi-layer structure. Regarding the organometallic gel layer (40) being a single-layer structure, the organometallic gel layer (40) is formed by polymerization of an organic precursor mixture containing decomposable lithium salts and lithium-affinity organic monomers induced by a polymerization initiator; The organometallic gel layer (40) is a stacked structure. The layer of the organometallic gel layer (40) near the negative electrode (30) is formed by polymerization of an organic precursor mixture containing decomposable lithium salt induced by a polymerization initiator. The layer of the organometallic gel layer (40) near the solid electrolyte layer (10) is formed by polymerization of an organic precursor mixture containing decomposable lithium salt and lithium-affinity organic monomers induced by a polymerization initiator.

3. The solid-state battery according to claim 2, characterized in that, The decomposable lithium salt contains at least one compound capable of decomposing into lithium fluoride, lithium borate, lithium oxide, or lithium phosphate. And / or, The lithium-containing organic monomers include one or more of the following: vinylsilane, silicon (meth)acrylate, 3-(trimethoxysilyl)propylacrylate, and germanium diacrylate; And / or, The polymerization initiator is a photoinitiator or a thermal initiator.

4. The solid-state battery according to claim 2 or 3, characterized in that, The decomposable lithium salt is a dual anion system containing boron and fluorine atoms; Preferably, the decomposable lithium salt includes lithium difluoro(oxalate)borate, lithium bis(oxalate)borate, and lithium pyrophosphate; or, the decomposable lithium salt includes lithium bis(fluorosulfonyl)imide and lithium tetrafluoroborate.

5. The solid-state battery according to claim 1, characterized in that, The thickness of the inorganic lithium alloy network structure (51) is 1μm~2μm; And / or, The initial potential applied to the solid-state battery is 4.4V~5V.

6. A solid-state battery, characterized in that, include: The solid electrolyte layer (10), positive electrode (20), negative electrode (30), and interface layer (50) are provided. The positive electrode (20) and the negative electrode (30) are respectively disposed on both sides of the solid electrolyte layer (10); The interface layer (50) is disposed between the negative electrode (30) and the solid electrolyte layer (10) and is in direct contact with the negative electrode (30) and the solid electrolyte layer (10); The interface layer (50) includes an inorganic lithium alloy network structure (51) that is in direct contact with the solid electrolyte layer (10) and the negative electrode (30).

7. The solid-state battery according to claim 6, characterized in that, The inorganic lithium alloy network structure (51) includes lithium atoms and lithiumophile atoms; Preferably, the lithiumophilic atom comprises one or more of Si, Ge, Sn, and Al; And / or, The solid-state battery further includes: a layer containing LiF and LiB located between the interface layer (50) and the solid electrolyte layer (10). x O γ The conductive layer, where x and γ are non-zero positive numbers.

8. A method for preparing a solid-state battery, characterized in that, include: Step 1: Coat the organic precursor mixture on one side of the main surface of the negative electrode (30) and / or the main surface of one side of the solid electrolyte layer (10), wherein the organic precursor mixture includes: a polymerization initiator, a decomposable lithium salt and an organic monomer containing lithium-loving atoms; Step 2: Assemble the positive electrode (20), the negative electrode (30), and the solid electrolyte layer (10), wherein the organic precursor mixture is located between the negative electrode (30) and the solid electrolyte layer (10); Step 3: The assembled structure is subjected to light or heat treatment to polymerize the organic precursor mixture into an organometallic gel layer (40).

9. The preparation method according to claim 8, characterized in that, In the structure assembled in step 2, the thickness of the organic precursor mixture coated between the negative electrode (30) and the solid electrolyte layer (10) is 2μm~4μm.

10. The preparation method according to claim 8 or 9, characterized in that, The organic precursor mixture comprises: 46wt% to 52wt% by mass of an organic monomer containing lithium-philic atoms, 47wt% to 51wt% by mass of a decomposable lithium salt, and 1wt% to 3wt% by mass of a polymerization initiator. And / or, The preparation method further includes: step 4, applying a potential to the solid battery formed in step 3, so that the organometallic gel layer (40) is transformed into an interface layer (50) containing an inorganic lithium alloy network structure (51), wherein the inorganic lithium alloy network structure (51) is in direct contact with the solid electrolyte layer (10) and the negative electrode (30). Optionally, step 3 includes: for the case where the polymerization initiator included in the organic precursor mixture is a photoinitiator, irradiating the assembled structure with long-wavelength ultraviolet light with a wavelength of 315nm~400nm; or, Step 3 includes: if the polymerization initiator included in the organic precursor mixture is a thermal initiator, hot pressing the assembled structure at a temperature of 50°C to 70°C.

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