Solid-state electrolyte-lithium assembly, method of making the same, and solid-state battery comprising the same

Abstract

Disclosed are a solid-state electrolyte-lithium assembly, a preparation method thereof, and a solid-state lithium battery comprising the same. The solid-state electrolyte-lithium assembly comprises: a solid-state electrolyte having a first major surface and an opposite second major surface, wherein at least the first major surface has a plurality of uniformly sized holes arranged in an array form, the spacing between adjacent holes is no more than 10 microns, the distribution density of the holes is 10 5 ‑10 9 cm 2 −1, and the depth of the holes does not penetrate to the opposite surface; and a layer of metallic lithium or lithium alloy compounded on the first major surface, the metallic lithium or lithium alloy filling the holes on the first major surface and forming a layer with a thickness of 1-100 microns on the first major surface. The solid-state electrolyte-lithium assembly of the present application can greatly reduce the interface impedance between the solid-state electrolyte and the metallic lithium.

Description

Technical Field

[0001] This invention belongs to the field of energy batteries, and specifically relates to a component for lithium batteries, especially solid-state lithium batteries, and a method for preparing the same. Background Technology

[0002] Solid-state lithium-ion batteries have attracted much attention due to their higher safety and longer cycle life compared to traditional liquid lithium-ion batteries, and their ability to be combined with lithium metal anodes with higher specific capacity and lower electrode potential to obtain lithium-ion batteries with higher energy density.

[0003] However, solid-state lithium-ion batteries also face significant challenges, especially when combined with lithium metal anodes, which present four major issues: interfacial physical contact, interfacial reactions, interfacial space charge layers, and lithium dendrites. Among these, the tight contact between lithium metal and the solid electrolyte membrane is crucial for solid-state lithium-ion batteries. This contact directly determines lithium-ion transport at the interface and the battery's impedance, which in turn determines the battery's energy density and rate performance. Therefore, reducing the interfacial impedance between lithium metal and the solid electrolyte is particularly important for lithium metal solid-state batteries.

[0004] Currently, there are several methods to reduce the interfacial impedance between the lithium metal anode and the solid electrolyte membrane (especially solid electrolyte membranes containing inorganic solid electrolytes, such as lithium lanthanum zirconium oxide).

[0005] 1. Add a transition layer between the lithium metal anode and the solid electrolyte membrane. For example, in Chinese patent CN201910728075.4, a tin oxide transition layer is set between the lithium metal anode and the lithium lanthanum zirconium oxide solid electrolyte membrane by atomic layer deposition, thereby reducing the impedance between the two.

[0006] 2. Molten lithium metal (lithium alloy, a mixture of molten lithium and other substances) is combined with a solid electrolyte membrane, or with a transition layer on the solid electrolyte membrane. For example, in Chinese patent CN202011366060.7, during battery assembly, molten lithium metal is first melted in the negative electrode shell, and then a surface-pretreated solid electrolyte is placed on the molten negative electrode. After standing for 1-10 minutes, the solid electrolyte and the molten negative electrode are completely wetted. Then, cooling is performed to obtain a solid lithium battery negative electrode module integrating the negative electrode, solid electrolyte, and negative electrode shell. However, combining molten lithium metal with a solid electrolyte presents two problems: high temperatures damage the solid electrolyte membrane. For example, the polymer solid electrolyte—polyethylene oxide (PEO)—has a melting point of only 60°C, while the melting point of lithium metal is 180°C. At this temperature, the PEO membrane has already melted. The reaction between molten lithium and the solid electrolyte is accelerated and more intense at high temperatures, especially the reaction between inorganic oxide electrolytes and molten lithium, where oxygen atoms may be released, leading to combustion.

[0007] 3. Pores are formed on the surface of a solid electrolyte membrane by acid etching, and then a negative electrode material such as a lithium metal sheet is composited (see Chinese Patent CN201911397991.0). However, the pore morphology obtained by acid etching is uncontrollable, and this method is only applicable to some solid electrolytes that can react with acids (such as some oxide solid electrolytes).

[0008] There is still a need in this field for a safe and controllable process that can effectively reduce the interfacial impedance between the lithium metal anode and the solid electrolyte film. Summary of the Invention

[0009] One of the objectives of this invention is to provide a widely applicable, controllable solid electrolyte-lithium component and its preparation method that can effectively reduce the interfacial impedance between the lithium metal anode and the solid electrolyte film.

[0010] The above-mentioned objectives of the present invention can be achieved through the following technical solutions.

[0011] One aspect of the present invention provides a film-like solid electrolyte-lithium component, comprising:

[0012] A solid electrolyte having a first primary surface and an opposing second primary surface, wherein at least the first primary surface has a plurality of uniformly sized pores arranged in an array, the spacing between adjacent pores not exceeding 10 micrometers, and the pore distribution density being 102. 5 -10 9 pcs / cm 2 The depth of the hole does not extend to the opposite surface; and

[0013] At least a lithium metal or lithium alloy layer is laminated on the first main surface, wherein the lithium metal or lithium alloy in the lithium metal or lithium alloy layer fills the pores and forms a layer with a thickness of 1-100 μm on the first main surface.

[0014] In some embodiments, the hole satisfies at least one of the following conditions:

[0015] It has a cross-sectional shape that is circular, near-circular, square, or an irregular polygon;

[0016] The equivalent circle diameter is between 0.1 and 10 micrometers;

[0017] The deviation between the equivalent circle diameters of each hole shall not exceed 30%, for example, less than or equal to 20%.

[0018] In some embodiments, the solid electrolyte includes an inorganic solid electrolyte, an organic solid electrolyte, or an organic-inorganic composite solid electrolyte.

[0019] In some embodiments, inorganic solid electrolytes include oxide solid electrolytes and sulfide solid electrolytes; organic solid electrolytes include polymer solid electrolytes.

[0020] In some implementations, the array of holes is formed by laser etching.

[0021] In some implementations, the lithium metal or lithium alloy layer is formed by vapor deposition.

[0022] In some embodiments, the solid electrolyte-lithium assembly further includes a metal foil laminated on the lithium metal or lithium alloy layer, the metal foil including one of copper foil, carbon-coated copper foil, perforated copper foil, stainless steel foil, and nickel foil.

[0023] Another aspect of the present invention provides a method for preparing the above-mentioned solid electrolyte-lithium component, the method comprising:

[0024] Laser etching is used to form multiple uniformly sized pores arranged in an array on at least the first main surface of the solid electrolyte membrane.

[0025] A lithium metal or lithium alloy layer is formed on the first main surface using a vapor deposition method; and

[0026] Optionally, rolling is performed after vapor deposition.

[0027] In some implementations, both laser etching and vapor deposition processes are performed while the solid electrolyte membrane is cooled.

[0028] In some implementations, a mask or polymer can be pre-coated on the surface of the solid electrolyte, followed by laser etching to deposit metallic lithium or lithium alloy. After the holes are filled, the mask or polymer is removed, and metallic lithium or lithium alloy is deposited to form the solid electrolyte-lithium assembly.

[0029] In some implementations, lithium metal or lithium alloy can be pressure-composited after deposition to provide a thicker lithium layer as needed, thereby improving efficiency.

[0030] In some implementations, the solid electrolyte-lithium assembly can be composited with a metal foil (current collector) after depositing metallic lithium or a lithium alloy, and / or after pressure bonding of metallic lithium / lithium alloy.

[0031] Another aspect of the present invention provides a solid-state lithium battery comprising the above-described solid electrolyte-lithium component.

[0032] In some implementations, solid-state lithium batteries include primary batteries and secondary batteries.

[0033] Compared with the prior art, the above-mentioned technical solution of the present invention has at least one of the following beneficial effects:

[0034] 1. The combination of uniform pores on the surface of the solid electrolyte and the lithium metal layer formed by vapor deposition (thermal evaporation) results in a larger contact area and a tighter and more uniform contact between the lithium metal and the solid electrolyte membrane, thereby significantly reducing the interfacial impedance between the lithium metal and the solid electrolyte membrane.

[0035] 2. Both laser etching and vapor deposition processes can cool the solid electrolyte membrane, avoiding the problem of high temperature damaging the electrolyte membrane and accelerating the reaction between the solid electrolyte membrane and metallic lithium.

[0036] 3. This invention is applicable to solid electrolyte membranes made of various materials.

[0037] 4. The deposition of metallic lithium using vapor deposition allows for precise and flexible control of the lithium layer thickness, meeting the needs of different batteries. Attached Figure Description

[0038] Figure 1 This is a schematic diagram of a solid electrolyte-lithium assembly according to the present invention.

[0039] Figure 2 This is a schematic diagram of the hole diameter and spacing of the present invention.

[0040] Figure 3 This is an optical microscope image of the surface of the LLZO sheet after laser engraving in Example 1.

[0041] Figure 4 This is an electron microscope image of the LLZO sheet surface before acid etching in Example 2.

[0042] Figure 5 This is an electron microscope image of the LLZO sheet surface after acid etching in Example 2.

[0043] Figure 6 This is a comparison of the battery capacity decay curves of the experimental group and the control group in Example 2.

[0044] Figure 7 This is the equivalent circuit of the electrochemical impedance spectroscopy in Example 1.

[0045] Figure 8 This is the equivalent circuit for the electrochemical impedance spectroscopy in Example 3. Detailed Implementation

[0046] To make the objectives, technical solutions, and advantages of this invention clearer, the specific embodiments of this invention will be further described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are only for explaining this invention and are not intended to limit this invention. Furthermore, the technical features involved in the various embodiments of this invention described below can be combined with each other as long as they do not conflict with each other.

[0047] Figure 1 This is a schematic diagram of a solid-state electrolyte-lithium assembly according to the present invention. Figure 1 As shown, the solid electrolyte-lithium assembly of the present invention includes a film-like solid electrolyte and a lithium metal or lithium alloy layer (in the present invention, the lithium metal or lithium alloy layer is collectively referred to as the lithium metal layer), and the lithium metal layer and the solid electrolyte are intercalated together (the lithium metal is partially embedded in the solid electrolyte, and the solid electrolyte is partially embedded in the lithium metal).

[0048] The inventors of this application have discovered that when uniform micropores of less than micrometer size are formed on the surface of a solid electrolyte in a uniformly distributed manner (array form) and a lithium metal layer is formed on the surface by deposition (thermal evaporation), not only is the contact area between the lithium metal and the solid electrolyte increased, but also the uniform and close contact between the lithium metal and the solid electrolyte is ensured, thereby greatly reducing the overall interfacial impedance between the lithium metal and the solid electrolyte.

[0049] Based on the above findings, the solid electrolyte used in this invention is a film structure having a first main surface and an opposing second main surface, wherein at least the first main surface has a plurality of uniformly sized pores arranged in an array, the spacing between adjacent pores not exceeding 10 micrometers, and the pore distribution density is 10. 5 -10 9 pcs / cm 2 The depth of the hole does not extend to the opposite surface.

[0050] In this invention, the holes can have a circular, near-circular, square, or irregular polygonal cross-sectional shape. The diameter of the hole (or the diameter of its circumscribed circle (or equivalent circle) in the case of an irregular shape) can be less than 10 micrometers, for example, 0.01-10 micrometers, 0.1-10 micrometers, or 0.1-5.0 micrometers. Uniform hole size means that the deviation between the diameters of the individual holes does not exceed 30%, for example, less than 20% or less than 10%.

[0051] To avoid contact between adjacent holes, the diameter of the hole is smaller than the distance between adjacent holes. Here, the distance between adjacent holes refers to the distance between the centers (equivalent circle centers) of adjacent holes. Figure 2 A schematic diagram showing the hole diameter and spacing of the present invention is provided.

[0052] In some implementations, the depth of the hole can be 1-1000 micrometers, for example 1-100 micrometers, or 1-10 micrometers.

[0053] In this invention, pores are formed on the surface of the solid electrolyte to increase the contact area between the solid electrolyte and lithium metal. The smaller the pore diameter and the smaller the pore spacing, the greater the pore density and the larger the contact area between the solid electrolyte and lithium metal. Furthermore, increasing the pore depth increases the lateral surface area of ​​the pores, thereby also increasing the contact area between the solid electrolyte and lithium metal. Ensuring that the pores are of uniform size and arranged in an array ensures the uniformity of the contact between the solid electrolyte and lithium metal.

[0054] Building upon the above, this invention further enhances the uniformity and tightness of the contact between the solid electrolyte and lithium metal by uniformly filling the pores with lithium metal and forming a uniform layer on the surface of the solid electrolyte. In particular, forming the lithium metal layer through deposition (thermal evaporation) allows for a tighter and more uniform contact and bonding between the lithium metal and the solid electrolyte film, thereby significantly reducing the interfacial resistance between them.

[0055] In this invention, the thickness of the lithium metal layer can be 1-100 μm, for example 5-100 μm, or 10-50 μm. Here, the thickness of the lithium metal layer refers to the thickness relative to the surface of the solid electrolyte without pores.

[0056] Here, metallic lithium includes elemental lithium and lithium alloys. Lithium alloys are alloys formed from elemental lithium and at least one of aluminum, gold, silver, magnesium, potassium, sodium, silicon, tin, indium, and zinc, wherein the mass percentage of lithium is 1-99%, preferably 50-95%.

[0057] The solid electrolyte membrane of the present invention can form a pore array on both main surfaces and composite a lithium metal layer on both surfaces. The pore array and the lithium metal layer on the two main surfaces can be the same or different.

[0058] In this invention, the solid electrolyte membrane can be a thin film with lithium-ion transport properties, and the material used to form such a thin film can be selected from the following materials 1-4.

[0059] 1. Polymer electrolytes (complexes of polymers and lithium salts)

[0060] The polymer is a copolymer or mixture of the above polymers, including polyethylene oxide (PEO), polyethylene glycol, polysiloxane, polytrimethylene carbonate, polycarbonate, polyvinyl carbonate, polypropylene carbonate, polyvinyl carbonate, polyvinylidene fluoride, polyacrylonitrile, polymethyl methacrylate, poly(vinylidene fluoride-hexafluoropropylene), polyphenylene thionine, and p-benzoquinone.

[0061] The lithium salt includes at least one of the following: lithium hexafluorophosphate (LiPF6), lithium perchlorate (LiClO4), lithium hexafluoroarsenate (LiAsF6), lithium tetrafluoroborate (LiBF4), lithium trifluoromethanesulfonate (LiCF3SO3), lithium bis(trifluoromethanesulfonyl)imide (LiTFSI), lithium bis(fluorosulfonyl)imide (LiFSI), lithium bis(oxalateborate)borate (LiBOB), lithium difluorooxalateborate (LiODFB), and lithium hydroxide (LiOH).

[0062] 2. Sulfide solid electrolytes, including: Li₂S-P₂S₅, Li₂S-SiS₂, Li₂S-B₂S₃, Li₂S-SiS₂, Li₂S-GeS₂, Li₆PS₅Cl, Li₆PS₅Br, Li₆PS₅I, Li₇Ge₃PS 12 , Li3PS4, Li4GeS4, Li4SiS4, Li4SnS4, Li 10 GeP2S 12 (LGPS), Li 10 SiP2S 12 Li 10 SnP2S 12 Li 9.5 4Si 1.74 P 1.44 S 11.7 Cl 0.3 .

[0063] 3. Oxide solid electrolytes, including: sodium superionic conductor solid electrolytes (NASICON): LiTi2(PO4)3 and LiGe2(PO4)3; lithium superionic conductor solid electrolytes (LISICON): Li 3+x X x Y 1-x O4 (X = Si, Ge, Ti; Y = P, As, V); perovskite-type solid electrolyte Li 3X La 2 / 3-X TiO3; Garnet-type solid electrolytes: A3B2(XO4)3 (A=Ca,Mg,Y,La; B=Al,Fe,Ga,Ge,Mn,Ni,V; X=Si,Ge,Al); Trans-perovskite-type solid electrolytes Li3OX (X=Cl,Br,I); LiPON, etc.

[0064] 4. Organic-inorganic composite solid electrolyte:

[0065] Organic phase: Homopolymer solid electrolyte

[0066] Inorganic phases include:

[0067] Nonionic conductive inorganic materials: SiO2, Al2O3, TiO2, γ-LiAlO2, montmorillonite, zirconium oxide, ZnS, MgAl2O4, MgAl2SiO6, BN, metal-organic framework (MOF).

[0068] Inorganic ionic conductors: oxide solid electrolytes, sulfide solid electrolytes.

[0069] The solid electrolyte membrane may also contain an electrolyte, which is composed of lithium salt and solvent.

[0070] The electrolyte content in the solid electrolyte membrane is ≤10% (mass fraction).

[0071] The lithium salt includes at least one of the following: lithium hexafluorophosphate (LiPF6), lithium perchlorate (LiCLO4), lithium hexafluoroarsenate (LiAsF6), lithium tetrafluoroborohydride (LiBF4), lithium trifluoromethanesulfonate (LiCF3SO3), lithium bis(trifluoromethanesulfonyl)imide (LiTFSI), lithium bis(fluorosulfonyl)imide (LiFSI), lithium bis(oxalateborate)borate (LiBOB), lithium difluorooxalateborate (LiODFB), and lithium hydroxide (LiOH).

[0072] The solvents include: ethylene carbonate (EC), propylene carbonate (PC), dimethyl carbonate (DMC), diethyl carbonate (DEC), methyl ethyl carbonate (EMC), methyl propyl carbonate (MPC), tetrahydrofuran (DOL), 2-methyltetrahydrofuran (2-MeTHF), 1,3-dioxocyclopentane (DOL), 4-methyl-1,3-dioxocyclopentane (4-MeDOL), dimethylmethane (DMM), 1,2-dimethoxyethane (DME), 1,2-dimethoxypropane (DMP), diethylene glycol dimethyl ether (DG), etc.

[0073] In addition to the solid electrolyte and lithium metal layer described above, the solid electrolyte-lithium assembly of the present invention may further include a metal foil laminated onto the lithium metal layer. The metal foil may be a lithium foil (lithium strip) or a lithium-copper composite strip, which can be laminated onto the lithium metal layer by pressure bonding. The metal foil can be used as a current collector or a tab.

[0074] In addition to the solid electrolyte and lithium metal layer described above, the solid electrolyte-lithium assembly of the present invention may also include a metal foil laminated on the lithium metal layer.

[0075] The metal foil can be lithium foil (lithium strip) or lithium-copper composite strip.

[0076] The metal foil may also be a lithium-free metal foil, including: copper foil, carbon-coated copper foil, perforated copper foil, stainless steel foil, and nickel foil.

[0077] The metal foil can be bonded to the lithium metal layer by pressure bonding.

[0078] Metal foil can be used as a current collector or a tab.

[0079] The solid-state electrolyte-lithium assembly of the present invention can be used in solid-state lithium batteries, such as solid-state lithium primary batteries or solid-state lithium secondary batteries. The solid-state electrolyte-lithium assembly can act as a solid electrolyte and an electrode (typically a negative electrode).

[0080] In solid-state lithium secondary batteries, the cathode material may include at least one material selected from the following: lithium iron phosphate (LiFePO4), lithium oxide (LiMn2O4), lithium cobalt oxide (LiCoO2), lithium nickel cobalt manganese oxide (LiNiCoMnO2), and lithium nickel cobalt aluminum oxide (LiNi... x Co y Al z O2 (0 < x, y, z < 1, x + y + z = 1), sulfur, carbon, oxygen, air, vanadium pentoxide, etc.

[0081] The shape of the battery can be selected from one of the following: button cell, cylindrical, square with steel casing, square with aluminum casing, pouch cell, linear cell, flexible and bendable cell, etc.

[0082] The solid electrolyte-lithium component of the present invention can be prepared by the following steps:

[0083] 1. Prepare a solid electrolyte membrane;

[0084] 2. A hole array is prepared on at least one surface of a solid electrolyte membrane by laser etching;

[0085] 3. A lithium metal layer is formed on the surface of a solid electrolyte membrane by filling the pores with a vapor phase deposition method.

[0086] The preparation method may also include:

[0087] 4. Pressure bond the membrane material prepared in step 3 with lithium foil (lithium strip) or lithium-copper composite strip.

[0088] Laser etching can be performed using laser machines known in the art, and the size and depth of the holes can be controlled by adjusting the laser power and etching time. Alternatively, the size and shape of the holes can be controlled using masks or similar methods.

[0089] Vacuum levels in vapor deposition (thermal evaporation) can reach 10. -1 -10 -5 Pa, the temperature can be 400–1200℃.

[0090] Cooling equipment can be used to control / regulate the temperature of the solid electrolyte membrane during laser etching and / or thermal evaporation. For example, during thermal evaporation, the solid electrolyte membrane can be cooled to 10–100°C to avoid damage to the solid electrolyte membrane due to high temperature.

[0091] The solid electrolyte-lithium component and its preparation method of the present invention will be further described below by way of example with specific embodiments. The various product structural parameters, reaction participants and process conditions used in the following embodiments are all typical examples. However, after extensive testing and verification by the inventors, other different structural parameters, other types of reaction participants and other process conditions listed above are also applicable and can all achieve the technical effects claimed by the present invention.

[0092] Example 1:

[0093] 1. Oxide solid electrolyte membrane treatment

[0094] The electrolyte membrane uses lithium lanthanum zirconium oxide (hereinafter referred to as LLZO sheet, Shenzhen Kejing).

[0095] The LLZO flakes are first polished with 400-grit and 1500-grit sandpaper to remove surface contaminants.

[0096] LLZO sheet 1, LLZO sheet 2 and LLZO sheet 3: The polished LLZO sheets are transferred to a laser engraving machine to engrave holes on their surface. Figure 3 This is an optical microscope image of the holes on the surface of an LLZO sheet after laser engraving. As can be seen from the image, the hole diameter is about 2 micrometers and the hole spacing is about 1.5 micrometers.

[0097] LLZO sheet 4, LLZO sheet 5 and LLZO sheet 6: Only polished, no other treatment is done.

[0098] The processed LLZO sheets 1, LLZO sheet 2, LLZO sheet 3, LLZO sheet 4, LLZO sheet 5 and LLZO sheet 6 were dried at 200℃ for 12 hours.

[0099] 2. Lithium metal deposited on oxide solid electrolyte membrane

[0100] Place a stainless steel ring-shaped mask (15mm outer diameter, 10mm inner diameter) on each side of the LLZO sheet 1, keeping the two rings and the LLZO sheet concentric and fixed.

[0101] The fixed mask and LLZO wafer were transferred to the coating setup. Lithium metal was deposited on both sides of the LLZO wafer at a temperature of 750°C and a vacuum level of 10. -3 Pa, the LLZO sheet is placed in close contact with the cooler of the vapor deposition equipment to prevent the LLZO temperature from becoming too high.

[0102] After vapor deposition, the mask is removed, and the thickness of the lithium metal layer on the surface of LLZO wafer 1 is approximately 20 micrometers.

[0103] Similarly, lithium metal is also deposited on both sides of the LLZO sheet 4.

[0104] The lithium-plated LLZO sheets 1, LLZO sheet 2, LLZO sheet 3, lithium-plated LLZO sheet 4, LLZO sheet 5 and LLZO sheet 6 were transferred to an argon glove box, where the water and oxygen content was all below 1 ppm.

[0105] 3. Battery assembly

[0106] The batteries used in the experiment were all 2032 button batteries.

[0107] Experimental group: stainless steel sheets were placed in sequence, LLZO sheet after lithium plating 1 Stainless steel sheets and springs are placed in the positive electrode shell and stacked concentrically. After adding the negative electrode shell and pressurizing and sealing, the final battery is obtained.

[0108] Control group 1: Stainless steel sheet, lithium sheet (50μm thick, 10mm in diameter) were sequentially placed... LLZO tablets 2 A lithium sheet (50μm thick, 10mm in diameter) and a stainless steel sheet are placed concentrically and neatly within the positive electrode casing. The positive electrode casing is then placed on a hot plate and heated to 250°C. Heating melts the lithium metal sheet, while pressure is applied to the stainless steel sheet to ensure close contact between the molten lithium and the solid electrolyte. The hot plate is then removed, and after cooling to room temperature, a spring sheet and a negative electrode casing are added. The casing is then pressurized and sealed to obtain the final battery.

[0109] Control group 2: Stainless steel sheet, lithium sheet (50μm thick, 10mm in diameter) were sequentially placed... LLZO tablets 3 A lithium sheet (50μm thick, 10mm in diameter), a stainless steel sheet, and a spring sheet are placed into the positive electrode shell, and then the negative electrode shell is added. After pressure sealing, the final battery is obtained.

[0110] Control group 3: Stainless steel sheets were placed in sequence, LLZO sheet after lithium plating 4 Stainless steel sheets and springs are placed in the positive electrode shell and stacked concentrically. After adding the negative electrode shell and pressurizing and sealing, the final battery is obtained.

[0111] Control Group 4: A stainless steel sheet, a lithium sheet (50μm thick, 10mm diameter), an LLZO sheet, and another lithium sheet (50μm thick, 10mm diameter) were sequentially placed in the positive electrode shell and stacked concentrically. The positive electrode shell was then placed on a hot plate and heated to 250℃. Heating melted the lithium metal sheet, while pressure was applied to the stainless steel sheet to ensure close contact between the molten lithium and the solid electrolyte. The hot plate was then removed, and after cooling to room temperature, a spring sheet and a negative electrode shell were added. The battery was then pressurized and sealed to obtain the final battery.

[0112] Control group 5: Stainless steel sheet, lithium sheet (50μm thick, 10mm in diameter) were sequentially placed... LLZO tablets 6 A lithium sheet (50μm thick, 10mm in diameter), a stainless steel sheet, and a spring sheet are placed into the positive electrode shell, and then the negative electrode shell is added. After pressure sealing, the final battery is obtained.

[0113] 4. Impedance test

[0114] Electrochemical impedance spectroscopy (EIS) measurements of the batteries in experimental groups, control groups 1, 2, 3, 4, and 5 were performed on a Shanghai Chenhua electrochemical workstation, with a frequency range of 1 MHz to 0.1 Hz and an applied bias voltage of 10 mV. The obtained EIS spectra were obtained using... Figure 7 The equivalent circuit shown is fitted, where Rb is the bulk resistance, Rg is the grain boundary resistance, Ri is the interface resistance, and CPE is the constant-phase element. Table 1 shows the fitted grain boundary resistance and interface resistance values.

[0115] As shown in Table 1, regardless of whether laser engraving is used on the surface of the oxide solid electrolyte membrane, the interface resistance of lithium metal composite by vapor deposition is the lowest, followed by molten lithium composite, while pressure composite has the highest interface resistance. This may be because the contact between lithium metal and the solid electrolyte membrane is tighter when using vapor deposition or molten lithium composite, while pressure composite results in gaps between lithium metal and the solid electrolyte membrane, leading to a looser interface contact and higher interface resistance.

[0116] The comparison shows that when oxide solid electrolyte membrane engraving and lithium metal evaporation are used simultaneously, the interface impedance is lower than that of using only lithium metal evaporation (Control Experiment 3) or only solid electrolyte surface engraving (Control Experiment 1 and Control Experiment 2). This indicates that there is a synergistic effect between lithium metal evaporation and solid electrolyte membrane engraving, resulting in a lower interface impedance.

[0117] Table 1 shows the results of impedance spectrum fitting in Example 1.

[0118]

[0119] Example 2

[0120] Experimental group LLZO tablets: Same as the experimental group in Example 1.

[0121] Control group LLZO tablets: Concentrated nitric acid was dropped onto the two surfaces of the polished LLZO solid electrolyte tablets in sequence, and treated for 3 minutes each. Then, the tablets were washed with deionized water and ultrasonically cleaned in deionized water for 3 minutes to obtain acid-treated LLZO tablets. Figure 4 This is an electron microscope image of the original LLZ0 slide. Figure 5Electron micrographs of LLZO sheets after acid etching show that the interparticle spacing of LLZO increases after acid etching. Compared with the pores formed by laser etching, the pores formed by acid etching are more irregular in shape and have a lower pore density.

[0122] The LLZO sheets of the experimental and control groups were transferred to a vapor deposition equipment, where metallic lithium was vapor deposited on their surfaces. They were then assembled into batteries, and finally, electrochemical impedance spectroscopy was tested (the vapor deposition, battery assembly, and impedance spectroscopy testing processes were the same as in Example 1).

[0123] Table 2 shows the results of the interface impedance test.

[0124] Table 2 Impedance spectrum fitting results in Example 2

[0125] experimental group Laser engraving Evaporation 8 control group acid corrosion Evaporation 15

[0126] As can be seen from the table, the interfacial impedance of the experimental group is smaller than that of the control group. This may be because the surface area of ​​the pores obtained by acid etching is smaller than that obtained by laser etching, and therefore the contact area between lithium metal and solid electrolyte is also smaller, resulting in a larger interfacial resistance.

[0127] Full battery test

[0128] Weigh the above materials according to the ratio of lithium iron phosphate: lithium lanthanum zirconium oxide particles: acetylene black: styrene-butadiene rubber = 5:2:1:1, add p-xylene, stir at room temperature for 12 hours to obtain positive electrode slurry (solid content is 20%).

[0129] A stainless steel annular mask (15 mm outer diameter, 10 mm inner diameter) was placed on the laser-etched and acid-etched surfaces of the LLZO wafers in both the experimental and control groups. The annular mask and the LLZO wafer were kept concentric and fixed.

[0130] The fixed mask and LLZO sheet were transferred to the coating setup, and lithium metal was deposited by evaporation at a temperature of 750°C and a vacuum degree of 10. -3 Pa, the LLZO sheet is placed in close contact with the cooler of the vapor deposition equipment to prevent the LLZO temperature from becoming too high.

[0131] After vapor deposition, the mask is removed, and the thickness of the lithium metal layer on the LLZO wafer surface is 20 micrometers.

[0132] The positive electrode slurry was coated on the side of the LLZO wafers in the experimental and control groups that was not coated with metallic lithium. It was first dried at room temperature for 12 hours, and then vacuum dried at 80°C for 24 hours to remove the solvent.

[0133] The full cell uses CR2032 button cell batteries. LLZO sheets coated with positive electrode and vapor-deposited lithium negative electrode are placed in the positive electrode shell, with the positive electrode in contact with the positive electrode shell. Stainless steel sheets and spring sheets are then placed in sequence, and finally the negative electrode shell is added. After pressure sealing, the final full cell is obtained.

[0134] The full battery test was performed on a Newway battery tester with a voltage range of 4.2–3.0V and a test current of 0.64mA / cm. 2 , Figure 3 The charge-discharge cycle curves are for the 1st (a), 20th (b), 30th (c), and 40th (d) cycles of the battery.

[0135] Figure 6 The figures show the capacity decay curves of the experimental and control groups in Example 1. As can be seen, the control group's battery capacity decays faster than the experimental group. This is likely because the LLZO in the experimental group uses laser etching to create pores, resulting in a more uniform pore distribution and more even deposition of lithium ions from the positive electrode at the negative electrode. In contrast, the control group uses acid etching to create empty pores, leading to uneven pore distribution, lithium metal deposition, and dendrite formation, thus causing faster capacity decay.

[0136] Example 3: Polymer Solid Electrolyte Membrane

[0137] 1. Preparation of polymer solid electrolyte membranes

[0138] Weigh out 5 grams of PEO and dissolve it in 90 grams of acetonitrile. Stir for 12 hours to completely dissolve the PEO. Then, coat the solution onto a polytetrafluoroethylene (PTFE) plate with a thickness of 30 micrometers. Dry the plate at room temperature for 24 hours, and then vacuum dry it at 50°C for 24 hours to remove the dissolved PEO film, which has a thickness of 20 micrometers.

[0139] The PEO membrane was immersed in LiClO4-DMC solution for 1 hour, and then dried to remove the solvent, thus obtaining the polymer electrolyte membrane.

[0140] The polymer electrolyte is pressurized into a disc with a diameter of 12 mm.

[0141] 2. Polymer solid electrolyte membrane treatment

[0142] In the experimental group, pores were etched into the polymer electrolyte membrane using the same method as in Example 1. To avoid damage to the polymer membrane from the high temperature of the laser, cooling was stopped after etching a few pores, and then etching continued.

[0143] Control group 1 and control group 2 used unetched polymer electrolyte membranes.

[0144] 3. Lithium metal deposited on polymer solid electrolyte membrane

[0145] The electrolyte membranes of the experimental group and the control group were coated with lithium metal on both sides of the polymer solid electrolyte membrane using the same method as in Example 1.

[0146] To avoid damaging the polymer film with high temperatures, the method of vapor deposition is to vapor deposit one side first and then the other side. At the same time, the polymer film is tightly attached to the cooling pipe of the vapor deposition equipment to transfer the heat away.

[0147] 4. Impedance test

[0148] Using the same method as in Example 1, lithium-to-lithium batteries were assembled in the experimental group, control group 1, and control group 2. Impedance spectra were then measured and fitted. Because PEO has a low melting point (60°C), molten lithium would melt it, causing the battery to disconnect. Therefore, molten lithium was used to prepare lithium-to-lithium batteries by combining it with PEO.

[0149] Figure 8 This is the equivalent circuit diagram used for fitting. In this circuit diagram, R... b R is the bulk impedance of the polymer electrolyte membrane. i Let Q be the interfacial impedance of the lithium metal / solid electrolyte membrane, Q be the interfacial capacitance of the lithium metal / solid electrolyte membrane, and Z be the diffusion impedance.

[0150] Table 2 shows the fitted results. As can be seen from the table, the interfacial impedance of control group 1 is lower than that of control group 2. This may be because control group 1 uses a vapor deposition method to prepare the lithium metal layer, which makes the contact between the lithium metal and the polymer electrolyte closer, thus resulting in a lower interfacial resistance. The interfacial impedance of the experimental group's battery is lower than that of control group 1. This may be because the surface of the polymer electrolyte membrane in the experimental group has etched holes, increasing the contact area between the lithium metal and the polymer electrolyte membrane, thus resulting in a lower interfacial resistance.

[0151] Table 2

[0152] experimental group 30 Control group 1 60 Control group 2 104

[0153] Example 4: Sulfide Solid Electrolyte Membrane

[0154] The sulfide electrolyte used is lithium-phosphorus-sulfur-chloride, which was purchased from Shenzhen Kejing Zhida Technology Co., Ltd.

[0155] Lithium phosphate, sulfur, and chlorine compounds and styrene-butadiene rubber (SBR) were added to p-xylene solvent in a 4:1 ratio and stirred for 12 hours. The mixture was then dried at 60°C for 24 hours to remove the solvent, yielding a lithium phosphate, sulfur, and chlorine-SBR mixture. The SBR acts as a binder in this mixture.

[0156] The surface treatment, lithium metal evaporation, battery impedance testing, and equivalent circuit diagrams of the experimental group, control group 1, and control group 2 were the same as in Example 1.

[0157] Table 3 shows the fitted results. As can be seen from the table, this may be because laser etching increases the contact area between lithium metal and the sulfide solid electrolyte film, and lithium metal evaporation increases the tightness of the contact between the two, resulting in a significant reduction in interfacial impedance.

[0158] experimental group 30 Control group 1 54 Control group 2 95

[0159] Example 5 Organic-inorganic composite solid electrolyte

[0160] Add 3g of PEO to 100ml of water and stir until completely dissolved. Add ammonia to the PEO-water mixture to adjust the pH to 11. Add 4g of tetraethyl orthosilicate and stir at 60℃ for 24 hours to hydrolyze the tetraethyl orthosilicate into SiO2 particles. Finally, add 0.9g of lithium perchlorate and stir for 2 hours.

[0161] The above liquid was heated to obtain a relatively viscous liquid, which was then coated on a polytetrafluoroethylene plate and dried at 60°C for 24 hours to obtain a PEO-SiO2-LiClO4 organic-inorganic composite solid electrolyte.

[0162] The surface treatment, lithium metal evaporation, lithium-to-lithium battery assembly, impedance testing, and circuit fitting for the experimental group, control group 1, and control group 2 were the same as in Example 3.

[0163] Table 4 shows the fitted results. As can be seen from the table, laser etching and lithium metal evaporation increase the contact area and density between the two, resulting in a significant reduction in interfacial impedance.

[0164] experimental group 76 Control group 1 126 Control group 2 215

[0165] Based on the disclosure and teachings of the foregoing specification, those skilled in the art can make appropriate changes and modifications to the above embodiments. Therefore, the present invention is not limited to the specific embodiments disclosed and described above, and some modifications and changes to the present invention should also fall within the protection scope of the claims of the present invention. Furthermore, although some specific terms are used in this specification, these terms are only for convenience of explanation and do not constitute any limitation on the present invention.

Claims

1. A film-like solid electrolyte-lithium component, characterized in that, The components include: A solid electrolyte having a first primary surface and an opposing second primary surface, wherein at least the first primary surface has a plurality of uniformly sized pores arranged in an array, the spacing between adjacent pores not exceeding 10 micrometers, and the pore distribution density being 102. 5 -10 9 pcs / cm 2 The depth of the hole does not extend to the opposite surface; and At least a lithium metal or lithium alloy layer is laminated on the first main surface, wherein the lithium metal or lithium alloy in the lithium metal or lithium alloy layer fills the pores and forms a layer with a thickness of 1-100 µm on the first main surface. The array of holes is formed by laser etching; the lithium metal or lithium alloy layer is formed by vapor deposition. The equivalent circular diameter of the holes is between 0.1 and 10 micrometers, and the deviation between the equivalent circular diameters of the individual holes does not exceed 30%. The solid electrolytes mentioned therein include inorganic solid electrolytes, organic solid electrolytes, or organic-inorganic composite solid electrolytes.

2. The solid electrolyte-lithium component according to claim 1, characterized in that, The hole has a circular, near-circular, square, or irregular polygonal cross-sectional shape.

3. The solid electrolyte-lithium component according to claim 1, characterized in that, The inorganic solid electrolyte includes oxide solid electrolytes and sulfide solid electrolytes; the organic solid electrolyte includes polymer solid electrolytes.

4. The solid electrolyte-lithium assembly according to any one of claims 1-3, characterized in that, The solid electrolyte-lithium assembly also includes a metal foil laminated on the lithium metal or lithium alloy layer.

5. A method for preparing a solid electrolyte-lithium component according to any one of claims 1-4, characterized in that, The method includes: Laser etching is used to form multiple uniformly sized pores arranged in an array on at least the first main surface of the solid electrolyte membrane. A lithium metal or lithium alloy layer is formed on the first main surface using a vapor deposition method; and Optionally, rolling is performed after vapor deposition. Both the laser etching and the vapor deposition are performed while the solid electrolyte membrane is cooled.

6. A solid-state lithium battery, characterized in that, The battery comprises a solid electrolyte-lithium component according to any one of claims 1-4.

7. The solid-state lithium battery according to claim 6, characterized in that, The battery includes a primary battery and a secondary battery.

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