All-solid-state battery and method for manufacturing the same

Abstract

This application discloses an all-solid-state battery and its fabrication method. The all-solid-state battery includes: a positive electrode, a solid electrolyte membrane, and a negative electrode, sequentially stacked; wherein, the all-solid-state battery further includes a polymer frame, the polymer frame circumferentially covering the edge of the positive electrode active material layer of the positive electrode and being at least partially covered by the solid electrolyte membrane; the side of the polymer frame in contact with the solid electrolyte membrane has a modified coating, the modified coating comprising an ion-conducting material. This application, by providing a modified coating between the polymer frame and the solid electrolyte membrane, can block interfacial side reactions and improve ion transport efficiency without affecting the original mechanical support and buffering functions.

Description

Technical Field

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

[0002] All-solid-state batteries use solid electrolytes instead of traditional separators and liquid electrolytes. The electrode-electrolyte interface is solid-solid, requiring high pressure to achieve good interfacial contact and ion transport performance. To address the problems of positive electrode edge collapse, tab breakage, and high short-circuit risk under high pressure, existing technologies propose buffer structures at the edges of the positive electrode active material layer. These buffer structures prevent electrode edge collapse and tab breakage, improving battery yield and structural stability. However, the interfacial compatibility between the buffer components and the solid electrolyte in existing technologies is poor. The frame substrate and the solid electrolyte (e.g., polymer frame and sulfide or halide solid electrolyte) are prone to interfacial side reactions under long-term use or high-temperature environments, generating insulating byproducts that block lithium-ion transport channels, affecting the battery's cycle stability and rate performance. Summary of the Invention

[0003] To address the aforementioned problems, this application discloses an all-solid-state battery and its fabrication method. The all-solid-state battery includes a polymer frame with a modified coating that improves the interfacial compatibility between the frame and the solid electrolyte membrane. Without affecting the original mechanical support and buffering functions, it can block interfacial side reactions and improve ion transport efficiency.

[0004] The first aspect of this application provides an all-solid-state battery, which may include: a positive electrode, a solid electrolyte membrane, and a negative electrode stacked sequentially; wherein, the all-solid-state battery further includes a polymer frame, which circumferentially covers the edge of the positive active material layer of the positive electrode and is at least partially covered by the solid electrolyte membrane; the side of the polymer frame in contact with the solid electrolyte membrane has a modified coating, which includes an ion-conducting material.

[0005] According to some embodiments of this application, the ratio of the elastic modulus of the modified coating to the elastic modulus of the polymer border can be (10:1)-(500:1).

[0006] According to some embodiments of this application, the modified coating can have an ionic conductivity ≥1×10⁻⁶ at 25°C. - 3 mS / cm.

[0007] According to some embodiments of this application, the density of the modified coating can be greater than 90%.

[0008] According to some embodiments of this application, the ion-conducting material may include one or more of the oxygen-containing inorganic acid salts of lithium, and / or one or more of the thioinorganic acid salts of lithium.

[0009] According to some embodiments of this application, the modified coating may further include a binder; the binder has a mass fraction of 10%-25%.

[0010] According to some embodiments of this application, the thickness of the polymer border can be 160μm-250μm; the thickness of the modified coating can be 100nm-300nm.

[0011] According to some embodiments of this application, the solid electrolyte membrane may include one or more of sulfide solid electrolytes, halide solid electrolytes, oxide solid electrolytes, and boride solid electrolytes.

[0012] A second aspect of this application provides a method for preparing an all-solid-state battery. The method may include: S1. providing a polymer frame and preparing a modified coating on one side of the polymer frame in the thickness direction to obtain a composite frame; S2. providing a positive electrode sheet and assembling the positive electrode sheet with the composite frame to obtain a composite positive electrode sheet; wherein the composite frame circumferentially covers the edge of the positive active material layer of the positive electrode sheet; S3. providing a negative electrode sheet and a solid electrolyte membrane, and sequentially stacking and assembling the composite positive electrode sheet, the solid electrolyte membrane, and the negative electrode sheet to obtain the all-solid-state battery; wherein, in the composite positive electrode sheet, the modified coating of the composite frame is at least partially in contact with the solid electrolyte membrane.

[0013] According to some embodiments of this application, the preparation of the modified coating in S1 can be achieved by atomic layer deposition or magnetron sputtering.

[0014] The all-solid-state battery provided in this application features an ion-conductive inert modified coating at the interface between the polymer frame and the solid electrolyte membrane. This coating forms a physical barrier, blocking direct contact between the polymer frame and the sulfide / halide solid electrolyte, thus preventing the formation of insulating byproducts. The modified coating exhibits excellent interfacial wettability with the solid electrolyte, enabling it to form a tight contact during hot pressing or isostatic pressing, preventing the generation of interfacial voids, further reducing interfacial impedance, and improving ion transport efficiency.

[0015] Additional aspects and advantages of this application will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of this application. Attached Figure Description

[0016] The disclosure of this application will become more readily understood with reference to the accompanying drawings. It will be readily understood by those skilled in the art that these drawings are for illustrative purposes only and are not intended to limit the scope of protection of this application. Furthermore, similar numbers in the drawings are used to denote similar components, wherein: Figure 1 These are exemplary structural diagrams of an all-solid-state battery according to some embodiments of this application; Figure 2 This is another exemplary structural diagram of an all-solid-state battery according to some embodiments of this application; Figure 3 This is an exemplary flowchart of a method for preparing an all-solid-state battery according to some embodiments of this application. Detailed Implementation

[0017] To make the above-mentioned objectives, features, and advantages of this application more apparent and understandable, the specific embodiments of this application are described in detail below. Many specific details are set forth in the following description to provide a thorough understanding of this application. However, this application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of this application. Therefore, this application is not limited to the specific embodiments disclosed below.

[0018] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. The terms “comprising” or “including” and similar terms used herein mean that an element or object preceding the word encompasses the elements or objects listed following the word and their equivalents, without excluding other elements or objects. The terms “and / or” or “and / or” as used herein include any and all combinations of one or more of the associated listed items.

[0019] The following describes some preferred embodiments of this application. It should be noted that the following description is for illustrative purposes only and is not intended to limit the scope of protection of this application. The steps involved in this application may be performed precisely in sequence, or various steps may be processed in reverse order or simultaneously. Furthermore, other operations may be added to these processes, or one or more steps may be removed from these processes.

[0020] This application provides an all-solid-state battery that may include a positive electrode sheet, a solid electrolyte membrane, and a negative electrode sheet stacked sequentially. The positive electrode sheet may include 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 may be prepared by using a positive active material, a positive binder, and a positive conductive agent to form a positive slurry, which is then coated onto the surface of the positive current collector and subjected to drying, pressing, and other processes. Alternatively, it may be prepared as a homogeneous mixture and then pressed and composited with the positive current collector. While forming the positive active material layer on the positive current collector, positive electrode tabs may also be formed simultaneously. For example, the positive current collector may be divided into a coated area and an empty foil area. The positive active material layer may be formed on the coated area. The empty foil area may form the positive electrode tabs with or without cutting. For example, cutting may form a single or multiple tabs protruding from the main body of the positive current collector. Alternatively, a full tab may be formed directly without cutting. In other examples, the positive electrode tab can be connected to the positive current collector by means of welding or other methods. This does not limit the scope of this application.

[0021] The all-solid-state battery also includes a polymer frame. (Reference) Figure 1 and Figure 2 Exemplary configuration diagrams of all-solid-state batteries according to some embodiments of this application are shown. Figure 1 and Figure 2 A cross-sectional view of the all-solid-state battery in the thickness direction (or vertical direction) is given, showing, from bottom to top, a positive electrode current collector 100, a positive electrode active material layer 200, a solid electrolyte membrane 400, and a negative electrode sheet (…). Figure 1 and Figure 2 (Not shown in the image). The polymer border 300 may circumferentially cover the edge of the positive electrode active layer 200. The term "circumferential coverage" may refer to coverage along the outer periphery of the coated material. Figure 1 and Figure 2As shown, the cross-section of the positive electrode active material layer 200 is rectangular, and the polymer frame 300 is also rectangular, disposed close to the outer surface of the positive electrode active material layer 200. In some embodiments of this application, the polymer frame 300 is made of one or more polymer materials, including but not limited to polyethylene terephthalate (PET), polytetrafluoroethylene (PTFE), polyphenylene sulfide (PPS), polyimide (PI), polycarbonate (PC), thermoplastic polyurethane elastomer (TPU), polyolefin elastomer (POE), polyurethane elastomer (PU), polyethylene (PE), polypropylene (PP), etc., or any combination thereof. The polymer frame 300 can be a single-layer structure or a multi-layer structure. When the polymer frame is a multi-layer structure, it may also include a rigid structural layer that provides mechanical support and / or a porous elastic layer that provides cushioning. For example, the rigid structural layer can be made of reinforced thermoplastic polymers, thermosetting rigid structural materials, inorganic rigid support skeletons, film-type rigid support layers, etc. The porous elastic layer can be made of porous polymer foams, rubber-based porous elastomers, silicon-based porous elastic materials, etc. The stacking order, number of layers, and composite method among the polymer layer, rigid structural layer, and porous elastic layer formed by the polymer can be adjusted according to the actual situation, and this application does not impose specific limitations.

[0022] To ensure effective insulation and prevent edge short circuits within the all-solid-state battery, the planar dimensions of the solid electrolyte membrane 400 should be larger than those of the positive electrode active material layer 200. This ensures that the membrane completely covers the positive electrode active material layer 200 and extends above at least a portion of the polymer frame 300. The extent to which the solid electrolyte membrane 400 extends beyond the positive electrode active material layer 200 can be determined based on actual assembly precision, ensuring that the positive electrode active material layer 200 is not exposed to the negative electrode side (e.g., in direct contact with the negative electrode sheet), thereby guaranteeing effective ion transport in the active region.

[0023] The polymer frame 300 has a modified coating 310 on the side that contacts the solid electrolyte membrane 400. The modified coating 310 may include an ion-conducting material. The ion-conducting material may include one or more of the oxygen-containing inorganic acid salts of lithium, and / or one or more of the thioinorganic acid salts of lithium. The oxygen-containing inorganic acid salts of lithium may include, but are not limited to, lithium phosphates such as Li3PO4, LiFePO4(LFP), LiMnPO4, Li3V2(PO4)3(LVP), LATP, LAGP, etc.; lithium silicates such as Li2SiO3, Li4SiO4, Li2Si2O5, etc.; lithium carbonates such as Li2CO3, etc.; lithium aluminates such as LiAlO2, Li5AlO4, etc.; and lithium titanates such as Li4Ti5O4. 12 Lithium nitrogen phosphates, such as Li₂TiO₃, etc. x PO y Nz (Li) 2.9 PO 3.3 N 0.4 The lithium thioinorganic acid salts include, but are not limited to, lithium gallates such as LiGaO2, Li3GaO3, and Li5GaO4; lithium indiums such as LiInO2 and Li3InO3; and lithium zirconates such as Li2ZrO3 and Li6Zr2O7, or any combination thereof. The lithium thioinorganic acid salts may include, but are not limited to, lithium thiophosphates such as Li3PS4 and Li7P3S. 11 Lithium thiosilicates include Li6PS5X (X = Cl, Br, I), Li2S-P2S5, etc.; lithium thiosilicates include Li4SiS4, Li4SiS4-Li3PS4, Li4SiS4-LiX, etc.; lithium thiogallium thioesters include Li3GaS3, LiGaS2, etc.; lithium thioindium thioesters include Li3InS3, LiInS2, etc.; and lithium thioaluminate thioesters include Li3AlS3, LiAlS2, Li2S... Al2S3 P2S5, etc., lithium thiotitanates such as Li4TiS4, Li2TiS3, etc., lithium thiozirconates such as Li4ZrS4, Li2ZrS3, etc., lithium thiogermanates such as Li4GeS4, Li 10 GeP2S 12 (LGPS), etc., lithium thiophosphates such as Li x P y S z N w One or any combination of the following. In some embodiments of this application, the ion-conducting material includes Li3PO4, Li2SiO3, Li2CO3, LiAlO2, and Li4Ti5O. 12 At least one of them.

[0024] In some implementations, the modified coating 310 can exhibit an ionic conductivity ≥1×10⁻⁶ at 25°C. -3 mS / cm. For example, the modified coating 310 can exhibit an ionic conductivity ≥1×10⁻⁶ at 25°C. -3 mS / cm, 2×10 -3 mS / cm, 3×10 - 3 mS / cm, 4×10 -3 mS / cm, 5×10 -3The modified coating 310 exhibits a density greater than 90%, measured in mS / cm, etc. This high density effectively isolates the polymer frame 300 from direct contact with the solid electrolyte membrane 400, preventing side reactions. The low porosity prevents interfacial voids and reduces interfacial impedance. Therefore, the modified coating 310 possesses excellent ionic conductivity and interfacial wettability, capable of filling the voids between the polymer frame 300 and the solid electrolyte membrane 400, forming a highly efficient lithium-ion transport channel, thereby reducing interfacial contact resistance.

[0025] The modified coating 310 can be formed on the side of the polymer frame 300 that contacts the solid electrolyte membrane 400 by suitable physical or chemical methods. Exemplary physical or chemical methods may include, but are not limited to, sol-gel methods, slurry coating methods, solution spin coating methods, magnetron sputtering methods, pulsed laser deposition methods, vacuum evaporation methods, atomic layer deposition methods, chemical vapor deposition methods, cold spraying methods, etc., as detailed in existing related materials. When using sol-gel methods, slurry coating methods, solution spin coating methods, cold spraying methods, etc., which involve solvent blending, the modified coating 310 may also include a binder. The ion-conducting material in the modified coating 310 may contain water-sensitive thioinorganic acid salts (such as sulfide solid electrolytes), therefore, oily binders and organic solvents (such as NMP, DMF, acetonitrile, etc.) should be preferentially used for slurry preparation to avoid hydrolysis side reactions. Oil-based adhesives include, but are not limited to, at least one of polyvinylidene fluoride-hexafluoropropylene copolymer (PVDF-HFP), polyimide (PI), polyethylene oxide (PEO), polyurethane elastomer (PU), polyolefin elastomer (POE), and styrene-butadiene rubber (SBR). When using an oil-based adhesive, an ion-conductive material can be mixed with the oil-based adhesive in an organic solvent to form a composite slurry, which is then directly coated onto the surface of the polymer frame 300 and dried to obtain a modified coating 310. Alternatively, an adhesive layer can first be formed on the side of the polymer frame 300 that contacts the solid electrolyte membrane 400 using the adhesive, and then the composite slurry prepared with the ion-conductive material can be coated on top of the adhesive layer to form an ion-conductive layer. The adhesive layer and the ion-conductive layer together constitute the modified coating 310.

[0026] If the selected ion-conducting material is only a water-insensitive oxide or oxyacid salt, a water-based binder (such as carboxymethyl cellulose CMC, polyacrylic acid PAA, sodium alginate, polyethylene glycol, etc.) and water can be used as solvents to prepare the slurry. However, attention must be paid to the drying temperature and time to completely remove moisture. It should be noted that when the ion-conducting material contains thioinorganic acid salts, water-based binders or any water-containing solvents cannot be used, otherwise it will cause the material to fail and produce toxic gases.

[0027] Regardless of the binder system used, the binder constitutes 10%-25% of the modified coating 310 by mass fraction. For the modified coating 310 described in this application, the preferred preparation method is a dry process without binder, such as atomic layer deposition (ALD) or magnetron sputtering. These methods avoid the influence of binder on ionic conductivity and obtain a high-density coating.

[0028] Since the modified coating 310 needs to simultaneously achieve the functions of barrier and efficient conduction, if the thickness is too thin, it is difficult to form a continuous and dense protective layer, which may not be able to completely block interfacial side reactions. If the thickness is too thick, it will significantly increase the lithium ion transport path, which may lead to an increase in interfacial impedance and may cause the total thickness of the composite structure to exceed that of the active material layer. Based on this, in this application, the thickness of the modified coating 310 can be 100nm-300nm. Optionally or preferably, the thickness of the modified coating 310 can be 150nm-200nm.

[0029] Since the modified coating 310 is formed on the polymer frame 300, the thickness of the polymer frame 300 and the elastic modulus of the polymer frame 300 and the modified coating 310 can be optimized to achieve smooth assembly and performance improvement of the all-solid-state battery. For example, the thickness of the polymer frame 300 can be 160μm-250μm. Optionally or preferably, the thickness of the polymer frame can be 190μm-210μm. The thickness of the polymer frame 300 and the modified coating 310 can be configured not to exceed the thickness of the positive electrode active material layer 200. This ensures that the composite structure formed by the polymer frame 300 and the modified coating 310 does not protrude from the surface of the positive electrode active material layer 200, avoiding additional stress concentration during the assembly and isostatic pressing of the all-solid-state battery, and ensuring the overall flatness and structural stability of the electrode. Furthermore, the modified coating 310 is only disposed on the interface layer surface where the polymer frame 300 contacts the solid electrolyte membrane 400, and does not affect the original mechanical support and buffering functions of the polymer frame.

[0030] The degree of elastic modulus matching between the modified coating 310 and the polymer frame 300 affects interface stability and long-term battery cycle life. When the modulus of the modified coating 310 is much higher than that of the polymer frame 300, the modified coating 310 acts as a rigid layer attached to the flexible frame. If the modulus difference is too large (e.g., exceeding 500:1), during isostatic pressure or battery charge-discharge processes, the polymer frame 300 undergoes significant deformation while the modified coating 310 struggles to deform synchronously, leading to shear stress at the interface. This can cause microcracks or even peeling of the modified coating 310, thus losing its function as a chemical barrier. Conversely, if the modulus of the modified coating 310 is too low relative to the polymer frame 300 (e.g., below 10:1), it lacks rigidity, is easily extruded under pressure, or has uneven thickness, failing to form a continuous and dense protective layer and failing to effectively support the edges of the positive electrode active material layer. Based on this, in this application, the ratio of the elastic modulus of the modified coating 310 to that of the polymer frame 300 can be optimized to (10:1)-(500:1). Optionally or preferably, the ratio of the elastic modulus of the modified coating 310 to that of the polymer frame 300 can be (50:1)-(200:1). Within this range, the modified coating 310 has sufficiently high rigidity to resist extrusion and deformation, while its modulus is not so high as to generate catastrophic interfacial stress with the flexible frame; the deformation behavior of the modified coating 310 and the polymer frame 300 is synergistic, the interfacial stress is minimized, and the two are most firmly bonded. The modified coating 310 remains intact and dense throughout the entire battery life cycle, thereby maximizing its function of blocking side reactions and conducting lithium ions. The matching of the elastic moduli of the two can ensure the mechanical integrity of the composite structure composed of the polymer frame 300 and the modified coating 310 during battery preparation and cycling, avoiding cracking or peeling of the modified coating 310.

[0031] Regarding other components of the all-solid-state battery, the positive electrode current collector can be implemented using a metal plate with electronic conductivity. Currently known positive electrode current collectors can all be used in this application. For example, the positive electrode current collector is aluminum foil.

[0032] The positive electrode active material may include, but is not limited to, layered compounds such as lithium cobalt oxide (LiCoO2), lithium nickel oxide (LiNiO2), and lithium nickel cobalt manganese oxide (LiNiO2). x Co y Mn 1–x–y O2, NCM), lithium nickel cobalt aluminum oxide (LiNi x Al y Mn 1–x–y O2, NCA, etc., or compounds substituted with one or more transition metals; lithium manganese oxides such as Li 1+x Mn 2–xO4 (x is 0~0.33), LiMnO3, LiMn2O3, LiMnO2, etc.; lithium copper oxides such as Li2CuO2; vanadium compounds such as LiV3O8, LiV3O4, V2O5, Cu2V2O7, etc.; with the molecular formula LiNi 1–x M x Lithium nickel oxide represented by O2 (where M = Co, Mn, Al, Cu, Fe, Mg, B or Ga, including at least one of the above elements, and x is 0.01~0.3); LiMn 2–x M x Lithium-manganese composite oxides represented by O2 (where M is Co, Ni, Fe, Cr, Zn, or Ta and x is 0.01~0.1) or the molecular formula Li2Mn3MO8 (where M is Fe, Co, Ni, Cu, or Zn); LiNi x Mn 2–x Spinel-type lithium-manganese composite oxides represented by O4; LiMn2O4 in which the Li part is replaced by alkaline earth metal ions; lithium disulfide compounds; Fe2(MoO4)3; lithium iron phosphate (LFP); lithium manganese iron phosphate (LFMP); lithium-rich manganese-based (xLi2MnO3) (1–x)LiMO2, M=Ni, Co, Mn); Li2Sn (n=1), lithium organosulfur compounds or carbon-sulfur polymers ((C2S x ) n (where x is 2.5~50, n is 2), etc. In addition, other lithium-containing transition metal oxides, transition metal fluorides, transition metal sulfides, transition metal fluorides, transition metal sulfides, or transition metal nitrides, as well as materials that are surface-coated or ion-doped with the above materials, can also be used as the positive electrode active material.

[0033] The positive electrode active material may also include solid electrolyte materials. For example, inorganic solid electrolytes, including but not limited to halide solid electrolytes, sulfide solid electrolytes, oxide solid electrolyte materials, nitride solid electrolytes, hydride solid electrolytes, borate solid electrolytes, etc.

[0034] Suitable, but not limited, halide solid electrolytes may include, but are not limited to, LaF3, LiCl, LiI, etc., or those with the chemical formula Li a MX bThis refers to lithium halide solid electrolytes, where M represents a metallic element or metalloid element, including one or more of B, Si, Ge, As, Sb, Te, Al, Zn, Mg, Ca, Ba, Mn, Cd, Co, Yb, Y, Cr, In, Ga, Sr, Hf, Ti, Ta, Sn, Nb, Er, Sc, etc., and X represents a halogen element such as F, Cl, Br, I, etc. For example, derivatives produced by doping or coating Li₂CdCl₄, Li₂MgCl₄, Li₂CdI₄, Li₂ZnI₄, Li₂ZrCl₆, Li₃YCl₆, Li₃InCl₆, or related materials.

[0035] Suitable, but not limiting, sulfide solid electrolytes may include, but are not limited to, Li2S. P2S5, Li2S P2S5–MS x (M=Si, Ge, Sn, 0≤x≤2), Li 9.6 P3S 12 Li7P3S 11 Li7P2S8I, Li 10 SnP2S 12 Li 10 SiP2S 12 Li9P3S9O3, LGPS(Li 10 GeP2S 12 Thio-LISICON (Li 3.25 Ge 0.25 P 0.75 S4), Li6PS5X (X=Cl, Br, I), Li3PS4-X (X=Cl, Br, I), Li4SnS4-X (X=Cl, Br), Li 3.25 Ge 0.25 P 0.75 S4, Li 3.4 Si 0.4 P 0.6 S4, Li 10 GeP2S 11.7 O 0.3 Li 9.54 Si 1.74 P 1.44 S 11.7 Cl 0.3 Li 10.35 Ge 1.35 P 1.65 S 12 Li 10.35 Si 1.35 P 1.65 S 12 Li 9.81 Sn0.81 P 2.19 S 12 Li 10 (Si 0.5 Ge 0.5 P2S 12 Li 10 (Ge 0.5 Sn 0.5 P2S 12 Li 10 (Si 0.5 Sn 0.5 P2S 12 Li6 (PS5) 0.7 (GeS4) 0.3 Cl、Li 7.5 P 2.5 Sn 0.5 S 10.5 Cl 1.5 Li6PS5Cl 0.5 Br 0.5 Li6PS5I 0.2 Cl 0.8 Li5SnS2C l3 Li 10 P3S 12 Cl2, Li7P2S 8.5 Cl 0.5 Derivatives produced by doping or coating with materials such as or any combination thereof or related materials.

[0036] Suitable, but not limited, oxide solid electrolytes may include, but are not limited to, NASICON-type solid electrolytes such as LiTi2(PO4)3, LiGeTi(PO4)3, LiGe2(PO4)3, LiHf2(PO4)3, and Li 1+x Al x Ge2 x (PO4)3(LAGP, where 0 ≤ x ≤ 2), Li 1+x Al x Ti2 x (PO4)3(LATP, where 0 ≤ x ≤ 2), Li 1+x Y x Zr2 x (PO4)3(LYZP, where 0≤x≤2), Li 1.3 Al 0.3 Ti 1.7 (PO4)3, Na3Zr2Si2PO 13 (NZSP) and other perovskite-type solid electrolytes such as Li3x La( 2 / 3 x )TiO3 (LLTO, where 0 < x < 0.25), LiSr 1.65 Zr 1.3 Ta 1.7 O9, Li 2x y Sr1 x Ta y Zr1 y O3 (where x = 0.75y and 0.60 < y < 0.75), etc., LISICON-type solid electrolytes such as Li 14 ZnGe4O 16 、Li4SiO4、LiGeO4, etc., garnet-type solid electrolytes such as Li7La3Zr2O 12 (LLZO)、Li 6.5 La3Zr<00,00138>Te 0.25 O 12 、Li 6.25 Al 0.25 >>La3Zr2O 12 、Li 6.2 Ga 0.3 La<o000146>Rb 0.05 Zr2O 12 、Li 6.85 La 2.9 Ca 0.1 Zr 1.75 Nb 0.25 O 12 、Li 6.75 La3Zr 1.75 Nb 0.25 O 12 、Li 6.75 La3Zr 1.75 Nb 0.25 O 12 etc., or derivatives produced by doping or coating improvement with any combination or related materials thereof.

[0037] Some suitable but non-limiting nitride solid electrolytes can include but are not limited to Li3N, Li7PN4, LiSi2N3, Li9N2Cl3, etc. Some suitable but non-limiting hydride solid electrolytes can include but are not limited to LiBH4, LiBH4-Li X It should be noted that there seems to be an error in the original text at line 40 where "<o000146>" is likely incorrect. This has been maintained as is in the translation for the purpose of following the instructions.(X = Cl, Br, or I), LiNH2, Li2NH, LiBH4-LiNH2, Li3AlH6, etc. Some suitable but not limited borate solid electrolytes may include, but are not limited to, Li2B4O7, Li2O-B2O3-P2O5, Li2B... 10 H 10 -Li2B 12 H 12 Examples include Li7N2I-0.5LiOH. Derivatives of these electrolytes obtained through substitution, doping, modification, and compositing can also serve as the inorganic solid electrolytes described in this application. For instance, bromine-substituted or partially substituted Li2ZrCl6, such as Li2ZrCl... 6-x Br x Rare earth metals such as lanthanum or yttrium-doped Li6PS5Br, and LLZO deposited on indium (In) surfaces, etc. It should be noted that the above examples are for illustrative purposes only and are not intended to limit the scope of this application.

[0038] Derivatives of the above solid electrolytes obtained through substitution, doping, modification, and compositing can also be used as inorganic solid electrolytes in this application. For example, bromine (Br)-substituted or partially substituted Li₂ZrCl₆, such as Li₂ZrCl₆... 6–x Br x Rare earth metals such as lanthanum or yttrium-doped Li6PS5Br, and LLZO deposited on indium (In) surfaces, etc. It should be noted that the above examples are for illustrative purposes only and are not intended to limit the scope of this application.

[0039] The positive electrode binder can be any known binder, including but not limited to polyvinylidene fluoride, polyvinylidene fluoride, polytetrafluoroethylene, polyethylene, polypropylene, aromatic polyamide resin, polyamide, polyimide, polyamide-imide, polyacrylonitrile, polyacrylic acid, polymethyl acrylate, polyethyl acrylate, polyhexyl acrylate, polymethacrylic acid, polymethyl methacrylate, polyethyl methacrylate, polyhexyl methacrylate, polyvinyl acetate, polyvinylpyrrolidone, polyether, polyethersulfone, polyhexafluoropropylene, styrene-butadiene rubber, carboxymethyl cellulose, etc., or any combination thereof, which can be used in this application. Copolymers can also be used as binders, exemplary of which are copolymers of two or more materials selected from tetrafluoroethylene, hexafluoroethylene, hexafluoropropylene, perfluoroalkyl vinyl ether, vinylidene fluoride, trifluorochloroethylene, ethylene, propylene, pentafluoropropylene, fluoromethyl vinyl ether, acrylic acid, hexadiene, etc. Alternatively, mixtures of two or more materials in the above examples can also be used as binders. In some implementations, the first binder may include, but is not limited to, polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), polyacrylic acid (PAA), styrene-butadiene rubber (SBR), carboxymethyl cellulose (CMC) and its derivatives such as sodium carboxymethyl cellulose (CMC-Na), polymethyl methacrylate (PMMA), polyacrylonitrile (PAN0), polyvinyl alcohol (PVA), polyaniline (PANI), polypyrrole (PPy), seaweed nanofibers (CNF), sodium alginate (Alg), β-cyclodextrin polymer β-CDp, polypropylene emulsion LA132, etc., or any combination thereof, or functionalized derivatives of the above polymers or copolymers between monomers.

[0040] The positive electrode conductive agent may include, but is not limited to, carbon-based materials such as graphite (natural or artificial graphite), carbon black (acetylene black, Ketjen black, Super P, etc.), carbon nanotubes, graphene, etc.; metal-based materials such as metal powders (aluminum powder, nickel powder, etc.), metal oxides (titanium oxide, etc.), metal whiskers (aluminum oxide, oxidizing agents, etc.); conductive polymers such as polyaniline, polypyrrole, polythiophene, etc.; conductive fibers such as carbon fibers, metal fibers, metal compound fibers, polymer fibers, etc.; or other known conductive agents.

[0041] The solid electrolyte membrane 400 may include a solid electrolyte material. The solid electrolyte material may be the aforementioned inorganic solid electrolyte or a polymer solid electrolyte. The polymer solid electrolyte may be composed of a polymer and a lithium salt. Suitable, but not limiting, polymers that participate in the formation of the polymer solid electrolyte may include, but are not limited to, polyether polymers, polycarbonate polymers, polyamide polymers, polyacrylate polymers, polysiloxane polymers, polyphosphazene polymers, polyolefin polymers, polyepoxide polymers, polyphosphate polymers, polyimide polymers, polyurethane polymers, and any combination thereof. For example, homopolymers such as polyethylene oxide (PEO) or copolymers (e.g., PEG-PPG block copolymers or PVDF-HFP) may participate in the formation of the polymer electrolyte. The lithium salt may include, but is not limited to, lithium bis(trifluoromethanesulfonyl)imide (LiTFSI), lithium bis(fluorosulfonyl)imide (LiFSI), lithium trifluoromethanesulfonate (LiOTF), lithium hexafluorophosphate (LiPF6), lithium hexafluoroborate (LiBF6), lithium difluorooxalate borate (LiDFOB), lithium bis(oxalate borate) (LiBOB), lithium difluorophosphate (LiPO2F2), lithium hexafluoroarsenate, and tris(pentafluoroethyl) Lithium trifluorophosphate, lithium perchlorate, lithium tetrafluoroborate, cyclodifluoromethane 1,1 Lithium bis(sulfonyl)imide, cyclodifluoromethane 1,1 Lithium bis(sulfonyl)imide, lithium bis(perfluoroethanesulfonyl)imide, lithium bis(fluoromalonic acid)borate, lithium tetracyanoborate, lithium dicyanotriazole salt, dicyano Trifluoromethyl Imidazole lithium salt, dicyano Pentafluoroethyl) Imidazole lithium salts or others. The inorganic solid electrolytes are described above and will not be repeated here.

[0042] In some implementations, the solid electrolyte membrane 400 may include at least one of sulfide solid electrolyte, halide solid electrolyte, oxide solid electrolyte, and boride solid electrolyte. For example, the solid electrolyte membrane 400 may be an LPSC sulfide solid electrolyte membrane, a Li3InCl6 halide solid electrolyte membrane, etc.

[0043] The negative electrode sheet may include a negative electrode current collector and a negative electrode active material layer located on at least one side of the negative electrode current collector. The negative electrode current collector can be implemented using a metal plate with electronic conductivity. Currently known negative electrode current collectors can all be used in this application. For example, the negative electrode current collector is a copper foil.

[0044] The negative electrode active material layer may include a negative electrode active material and at least one of a negative electrode binder or a negative electrode conductive agent. The negative electrode active material may be a material containing metal ions capable of intercalating or deintercalating lithium ions, and exemplary materials may be metallic materials (such as Li, Ag, Al, Bi, Cu, Ga, Ge, In, Ni, Pb, Sb, Si, Sn, Sr, Zn, etc., or alloys or compounds of the above metals, such as Li–Sn alloys, Li–Sn–O alloys, Sn, SnO, SnO2, TiO2–Li4Ti5O). 12 Li Al alloys, Ag–C alloys, etc., carbon materials (such as graphite including natural / artificial graphite, carbon fibers, soft carbon, hard carbon, crystalline carbon, amorphous carbon, etc.), silicon compounds (such as silicon, silicon-oxygen compounds, silicon-carbon compounds), or composite materials formed from metals and carbon / silicon. In some implementations, the negative electrode can be a silicon-containing negative electrode (Si / SiO). x / Si-C), lithium metal anode, lithium alloy anode (Li-Mg, Li-Al, Li-Sn, Li-In, Li-Zn), silver-carbon anode (Ag-C), lithium titanate anode (LTO, Li4Ti5O) 12 One of the following: When the negative electrode is a lithium metal negative electrode or a lithium alloy negative electrode, if self-supporting lithium foil or alloy foil is used, the negative electrode may not require a negative current collector.

[0045] The negative electrode binder and the negative electrode conductive agent may be the same as or similar to the aforementioned positive electrode binder and positive electrode conductive agent. Please refer to the foregoing description for details.

[0046] The all-solid-state battery disclosed in this application may have a polymer frame. An ion-conductive inert modified coating is formed at the contact interface between the polymer frame and the solid electrolyte membrane, creating a physical barrier that blocks direct contact between the polymer frame and the sulfide / halide solid electrolyte, thus preventing the formation of insulating byproducts. The modified coating exhibits good interfacial wettability with the solid electrolyte, enabling it to form a tight contact during hot pressing or isostatic pressing, preventing the generation of interfacial voids, further reducing interfacial impedance, and improving ion transport efficiency.

[0047] This application also discloses a method for fabricating an all-solid-state battery. (Reference) Figure 3 As an exemplary but not limiting illustration, the preparation method includes: S1. Provide a polymer frame and prepare a modified coating on one side of the polymer frame in the thickness direction to obtain a composite frame; S2. Provide a positive electrode sheet and assemble the positive electrode sheet with the composite frame to obtain a composite positive electrode sheet; S3. Provide a negative electrode sheet and a solid electrolyte membrane, and stack and assemble the composite positive electrode sheet, the solid electrolyte membrane and the negative electrode sheet in sequence to obtain the all-solid-state battery.

[0048] For step S1, the polymer frame can be obtained by cutting the layered polymer to size. For example, assuming the polymer frame is a polyimide (PI) frame, it can be obtained by cutting a large polyimide film. After completion, a cleaning operation can be performed (e.g., ultrasonic cleaning with ethanol / acetone / deionized water followed by nitrogen purging) to remove oil and impurities. The modified coating can be prepared using methods such as magnetron sputtering, atomic layer deposition (ALD), chemical vapor deposition (CVD), pulsed laser deposition (PLD), sol-gel method, or coating method. Taking ALD as an example, after the side surface of the polymer frame is cleaned with argon plasma, it is placed in the reaction chamber of the ALD system. After the precursor is pulsed, it is purged with inert gas or evacuated, and the cycle is repeated to deposit the modified coating on the polymer frame. Taking magnetron sputtering as an example, after cleaning and activation, the side surface of the polymer frame is placed in a sealed vacuum chamber. After introducing working gas into the cavity, target bombardment is initiated, causing target atoms to deposit on the side surface of the polymer frame. Taking the sol-gel method as an example, oil-based binders and organic solvents should be preferentially used for slurry preparation to avoid hydrolysis side reactions of the ion-conducting material. Specifically, the ion-conducting material and oil-based binder can be mixed in an organic solvent to prepare a composite sol, which is then directly coated onto the side surface of the polymer frame and dried to obtain a modified coating; alternatively, an binder layer can be formed on the side surface of the polymer frame first, followed by coating with a sol containing the ion-conducting material to form a composite structure. If the selected ion-conducting material is only a water-insensitive oxide or oxyacid salt, an aqueous binder and water can also be used as solvents. Of course, the above description is merely exemplary and not limiting, and other methods can also be used in this application.

[0049] For step S2, the positive electrode sheet may include a positive current collector and a positive active material layer located on the positive current collector. The assembly of the positive electrode sheet and the composite frame may be achieved by hot-pressing the positive electrode sheet and the composite frame together. For example, the composite frame circumferentially covers the edge of the positive active material layer, and the side with the modified coating faces away from the positive current collector. After placing both, and setting the hot-pressing temperature, pressure, and time, the equipment, such as a flatbed press, is started for pressing. After cooling, the composite positive electrode sheet is obtained.

[0050] For step S3, the negative electrode and the solid electrolyte membrane can be as described above. One example assembly method is to stack the composite positive electrode, the solid electrolyte membrane, and the negative electrode in sequence, with the composite positive electrode at the bottom and the modified coating facing upwards. The subsequently stacked solid electrolyte membrane will be in direct, at least partially, contact with the modified coating. The negative electrode will be placed on top. After stacking, the electrode will be encapsulated and pressed (e.g., by hot pressing, cold pressing, isostatic pressing, etc.) to finally obtain the all-solid-state battery.

[0051] The present application will be further described in detail below with reference to embodiments. It should be noted that the following embodiments are for illustrative purposes only and are not intended to limit the scope of protection claimed in this application.

[0052] Example 1 (1) The polymer frame is a double-layer frame formed by bonding a 120μm thick PET layer and a 50μm thick PE layer with UV glue, and is cut into a rectangle with an inner frame size of 4cm×5cm and an outer frame size of 5cm×6cm.

[0053] (2) The modified coating was prepared by atomic layer deposition. The PET side surface of the polymer frame was cleaned using argon plasma. The cleaned polymer frame was placed in the ALD reaction chamber and evacuated to 5 × 10⁻⁶. -4 The temperature was increased to 100℃. Using trimethyl phosphate and tert-butyllithium as precursors and water as the oxidant, the precursor pulse time was set to 0.3 s and the argon purge time to 2 s. Deposition was performed at a rate of approximately 1 nm / cycle, and a 200 nm thick Li3PO4 coating was deposited on the surface of the polymer frame by controlling the number of cycles. After deposition, the coating was annealed at 200℃ for 40 min under a nitrogen atmosphere. EIS testing showed that the ionic conductivity of the obtained Li3PO4 coating at 25℃ was 5.6 × 10⁻⁶. -3 The density is 98% and the elastic modulus of the Li3PO4 coating is 100:1 compared to that of the double-layer frame.

[0054] (3) Take an NCM811 positive electrode sheet with a thickness of 190 μm. The positive electrode sheet includes a positive current collector aluminum foil (12 μm) and a positive active material layer (the size of the active material layer is 4 cm × 5 cm; the conductive agent is SP and the binder is PVDF-HFP). It is hot-pressed and stacked with the polymer frame with modified coating obtained in step (2). The polymer frame is set on the outer periphery of the positive active material layer, with the modified coating facing upward. After stacking, it is hot-pressed on a flat plate at 75°C and 3 MPa pressure for 20 min. After cooling, a composite positive electrode sheet is obtained.

[0055] (4) Stack the composite positive electrode sheet (coating facing up) obtained in step (3), the LiPSCl sulfide solid electrolyte membrane with a size of 5cm×6cm, and the silicon negative electrode sheet with a size of 5cm×6cm in sequence. After welding the tabs, encapsulate with aluminum-plastic film, and then perform isostatic pressing at 500MPa for 5min to obtain an all-solid-state battery.

[0056] Example 2 (1) Polyimide (PI) frames with a thickness of 170μm were selected and cut into rectangles with an inner frame size of 4cm×5cm and an outer frame size of 5cm×6cm. The obtained frames were ultrasonically cleaned with acetone and anhydrous ethanol for 15min each, dried with nitrogen, and the interface oil and impurities were removed before use.

[0057] (2) Polyvinylidene fluoride-hexafluoropropylene copolymer (PVDF-HFP) was dissolved in N-methylpyrrolidone (NMP) to prepare a 2 wt% solution. This solution was then spin-coated at 2000 rpm onto the pretreated PI frame surface (i.e., the interface layer surface in contact with the solid electrolyte membrane) for 30 s. The solution was then dried in a vacuum oven at 80 °C for 2 h to form an adhesive underlayer with a thickness of approximately 50 nm. Tetraethyl orthosilicate (TEOS) and lithium nitrate (LiNO3) were weighed in a molar ratio of 1:2 and dissolved in a mixed solvent of anhydrous ethanol and deionized water (volume ratio of anhydrous ethanol to deionized water was 3:1). 5% of the total precursor mass of acetylacetone was added as a chelating agent, and the pH was adjusted to 4. The solution was stirred at 50 °C and 400 rpm for 40 min until completely dissolved. After aging in a sealed container at room temperature for 18 h, a Li2SiO3 sol with a viscosity of 80 mPa·s was obtained. The Li₂SiO₃ sol was coated onto the adhesive substrate using a slot coating method, with the wet film thickness controlled at 20 μm. After coating, the frame was pre-dried on a 60°C hot plate for 2 hours, then transferred to a vacuum oven and vacuum-dried at 120°C for 4 hours, forming a modified coating with a total thickness of 200 nm together with the adhesive layer. The PVDF-HFP adhesive accounted for 19% of the mass of this modified coating. The ionic conductivity of the modified coating at 25°C was measured to be 3.3 × 10⁻⁶. -3 The density is 96% (mS / cm), and the ratio of the elastic modulus of the modified coating to the elastic modulus of the PI frame is 80:1.

[0058] (3) Take an NCM811 positive electrode sheet with a thickness of 190 μm. The positive electrode sheet includes a positive current collector aluminum foil (12 μm) and a positive active material layer (the size of the active material layer is 4 cm × 5 cm; the conductive agent is SP and the binder is PVDF-HFP). It is hot-pressed and stacked with the polymer frame with modified coating obtained in step (2). The polymer frame is set on the outer periphery of the positive active material layer, with the modified coating facing upward. After stacking, it is hot-pressed on a flat plate at 75°C and 3 MPa pressure for 20 min. After cooling, a composite positive electrode sheet is obtained.

[0059] (4) Stack the composite positive electrode sheet (coating facing up) obtained in step (3), the LiPSCl sulfide solid electrolyte membrane with a size of 5cm×6cm, and the silicon negative electrode sheet with a size of 5cm×6cm in sequence. After welding the tabs, encapsulate with aluminum-plastic film, and then perform isostatic pressing at 500MPa for 5min to obtain an all-solid-state battery.

[0060] Example 3 (1) The polymer frame is made of 170μm thick polypropylene (PP) frame, cut into rectangles with inner frame size of 4cm×5cm and outer frame size of 5cm×6cm. It is ultrasonically cleaned with acetone and anhydrous ethanol for 15min each, and then dried with nitrogen for later use.

[0061] (2) Weigh tetraethyl orthosilicate (TEOS) and lithium nitrate (LiNO3) in a molar ratio of 1:2 and dissolve them in a mixed solvent of anhydrous ethanol and deionized water (volume ratio 3:1). Add 5% of the total precursor mass of acetylacetone as a chelating agent and adjust the pH to 4. Dissolve lithium-ionized polyacrylic acid (PAA-Li, water-based binder) in deionized water to prepare a 3wt% solution, and add it to the above sol at a ratio of 12% of the total precursor mass (the binder accounts for 10% of the final solids). Adjust the pH of the mixture to 8.5 with LiOH solution, stir at 50℃ and 400r / min for 40min, and then seal and age at room temperature for 18h to obtain an aqueous binder Li2SiO3 composite sol with a viscosity of 75mPa·s.

[0062] The composite sol was coated onto the upper surface of a PP frame using a slot coating method, with the wet film thickness controlled at 25 μm. After coating, the frame was pre-dried on a 60°C hot plate for 2 hours, then transferred to a vacuum oven and vacuum-dried at 100°C for 3 hours to form a modified coating with a thickness of 180 nm. Testing showed that the ionic conductivity of the modified coating at 25°C was 2.8 × 10⁻⁶. -3 The density is 95% and the ratio of the elastic modulus of the modified coating to that of the PP frame is 150:1.

[0063] (3) Take an NCM811 positive electrode sheet with a thickness of 190 μm. The positive electrode sheet includes a positive current collector aluminum foil (12 μm) and a positive active material layer (the size of the active material layer is 4 cm × 5 cm; the conductive agent is SP and the binder is PVDF-HFP). It is hot-pressed and stacked with the polymer frame with modified coating obtained in step (2). The polymer frame is set on the outer periphery of the positive active material layer, with the modified coating facing upward. After stacking, it is hot-pressed on a flat plate at 75°C and 3 MPa pressure for 20 min. After cooling, a composite positive electrode sheet is obtained.

[0064] (4) Stack the composite positive electrode sheet (coating facing up) obtained in step (3), the LiPSCl sulfide solid electrolyte membrane with a size of 5cm×6cm, and the silicon negative electrode sheet with a size of 5cm×6cm in sequence. After welding the tabs, encapsulate with aluminum-plastic film, and then perform isostatic pressing at 500MPa for 5min to obtain an all-solid-state battery.

[0065] Example 4 (1) The polymer frame is made of 175μm thick PTFE layer and cut into a rectangle with inner frame size of 4cm×5cm and outer frame size of 5cm×6cm.

[0066] (2) Modified coating was prepared by atomic layer deposition. The PTFE surface was cleaned using argon plasma, and the cleaned PTFE frame was placed in the ALD reaction chamber and evacuated to 5×10⁻⁶. - The pressure was increased to 4 Pa ​​and then heated to 100 °C. Using trimethyl phosphate and tert-butyllithium as precursors and water as the oxidant, the precursor pulse time was set to 0.3 s and the argon purge time to 2 s. Deposition was performed at a rate of approximately 1 nm / cycle, and a 150 nm thick Li3PO4 coating was deposited on the surface of the polymer frame by controlling the number of cycles. After deposition, the coating was annealed at 200 °C for 40 min under a nitrogen atmosphere. EIS testing showed that the ionic conductivity of the obtained Li3PO4 coating at 25 °C was 4.2 × 10⁻⁶. -3 The density is 97% and the elastic modulus of the Li3PO4 coating is 120:1 compared to that of the PTFE frame.

[0067] (3) Take an NCM811 positive electrode sheet with a thickness of 190 μm. The positive electrode sheet includes a positive current collector aluminum foil (12 μm) and a positive active material layer (the size of the active material layer is 4 cm × 5 cm; the conductive agent is SP and the binder is PVDF-HFP). It is hot-pressed and stacked with the polymer frame with modified coating obtained in step (2). The polymer frame is set on the outer periphery of the positive active material layer, with the modified coating facing upward. After stacking, it is hot-pressed on a flat plate at 75°C and 3 MPa pressure for 20 min. After cooling, a composite positive electrode sheet is obtained.

[0068] (4) Stack the composite positive electrode sheet (coating facing up) obtained in step (3), the Li3InCl6 halide solid electrolyte membrane with a size of 5cm×6cm, and the silicon negative electrode sheet with a size of 5cm×6cm in sequence. After welding the tabs, encapsulate with aluminum-plastic film, and then perform isostatic pressing at 500MPa for 5min to obtain an all-solid-state battery.

[0069] Comparative Example 1 Comparative Example 1 differs from Example 1 in that no modified coating was applied to the surface of the polymer frame, and the polymer frame was in direct contact with the solid electrolyte membrane. The specific preparation process is as follows.

[0070] (1) The polymer frame is the same double-layer frame as in Example 1: a double-layer frame formed by bonding a 120μm thick PET layer and a 50μm thick PE layer with UV adhesive, and cut into rectangles with an inner frame size of 4cm×5cm and an outer frame size of 5cm×6cm. It is ultrasonically cleaned with acetone and anhydrous ethanol for 15min each, and then dried with nitrogen for later use.

[0071] (2) No modified coating preparation is carried out, that is, the surface of the polymer frame has no coating.

[0072] (3) Take a 190μm thick NCM811 positive electrode sheet (12μm aluminum foil for positive electrode current collector, 4cm×5cm active material layer size; conductive agent SP, binder PVDF-HFP), and hot-press it with the polymer frame from step (1). The polymer frame is set on the outer periphery of the positive electrode active material layer. After stacking, it is hot-pressed on a flat plate at 75℃ and 3MPa pressure for 20min. After cooling, a composite positive electrode sheet is obtained.

[0073] (4) Stack the composite positive electrode sheet from step (3), the LiPSCl sulfide solid electrolyte membrane with a size of 5cm×6cm, and the silicon negative electrode sheet with a size of 5cm×6cm in sequence. After welding the tabs, encapsulate with aluminum-plastic film, and then perform isostatic pressing at 500MPa for 5min to obtain an all-solid-state battery.

[0074] Test Example 1 - Ionic Conductivity Test The modified coating was prepared as an independent membrane (10 mm in diameter and 200 nm in thickness), sandwiched between two stainless steel blocking electrodes, and encapsulated as a symmetrical cell. The symmetrical cell was placed in a constant temperature oven at 25 °C for 2 h, and the impedance spectrum was measured using an electrochemical workstation. The ionic conductivity was calculated by fitting the Nyquist plot (σ = L / (R × S), where L is the coating thickness, R is the interfacial impedance, and S is the electrode area).

[0075] Test Example 2 - Density Test Cross-sectional image analysis using scanning electron microscopy (SEM) was employed. A flat cross-section was obtained by focusing ion beam (FIB) cutting of the modified coating, and high-magnification SEM images were taken. The porosity was calculated using image processing software (ImageJ), and density was determined by subtracting porosity from pore area.

[0076] Test Example 3 - Elastic Modulus Test For modified coatings: Nanoindentation method was used with a Berkovich diamond indenter at a test temperature of 25℃. The maximum indentation depth was ≤ 1 / 10 of the coating thickness. More than 5 defect-free micro-areas were randomly selected on the coating surface for testing. The Young's modulus was calculated by fitting the Oliver-Pharr model and the average value was taken as the result.

[0077] For polymer frames: The tensile test method is used, and the tensile modulus is calculated by stretching at the corresponding rate at 25°C.

[0078] The parameters related to the above embodiments and comparative examples are shown in Table 1.

[0079] Table 1 Parameter Comparison Test Example 4 - Interface Impedance Test The interface impedance was tested using EIS at a temperature of 25°C and a frequency range of 1MHz to 10mHz. The AC amplitude was 5mV. After the all-solid-state battery was left to stand for 2 hours until the voltage stabilized, the impedance data was collected using an electrochemical workstation. The equivalent circuit was fitted according to the Nyquist plot (using "RS+Rint / / CPE", where RS is the series resistance and Rint is the interface impedance).

[0080] Test Example 5 - Loop Test The all-solid-state battery was charged and discharged at 25℃ and 0.1C rate, with a voltage range of 2.5V to 4.3V. The initial capacity and the capacity after 500 cycles were recorded, and the capacity retention rate was calculated.

[0081] The test results are shown in Table 2.

[0082] Table 2 Electrical performance test results As shown in Table 2, the test results indicate that the embodiments with the modified coating exhibit significantly improved interfacial compatibility, a significantly reduced interfacial impedance, and maintained a high capacity retention rate after 500 cycles. In contrast, the comparative examples without the modified coating show significantly increased interfacial impedance and drastically deteriorated cycle stability due to interfacial side reactions caused by direct contact between the polymer frame and the solid electrolyte membrane. This generates insulating byproducts that block lithium-ion transport channels. This demonstrates that the modified coating introduced between the polymer frame and the solid electrolyte membrane in this application effectively acts as a physical barrier, preventing interfacial side reactions. When the elastic modulus of the modified coating and the polymer frame are appropriately matched, the composite structure can remain intact during battery fabrication and cycling, preventing coating cracking or peeling, thereby ensuring the long-term cycle stability of the battery.

[0083] This application has described the basic concepts. Obviously, for those skilled in the art, the above detailed disclosure is merely illustrative and does not constitute a limitation of this application. Although not explicitly stated herein, those skilled in the art may make various modifications, improvements, and corrections to this application. Such modifications, improvements, and corrections are suggested in this application, and therefore such modifications, improvements, and corrections still fall within the spirit and scope of the exemplary embodiments of this application.

[0084] Furthermore, this application uses specific terms to describe its embodiments. For example, "an embodiment," "one embodiment," and / or "some embodiments" refer to a particular feature, structure, or characteristic related to at least one embodiment of this application. Therefore, it should be emphasized and noted that "an embodiment," "one embodiment," or "an alternative embodiment" mentioned twice or more in different locations in this application do not necessarily refer to the same embodiment. In addition, certain features, structures, or characteristics in one or more embodiments of this application can be appropriately combined.

[0085] Similarly, it should be noted that, in order to simplify the description of this application and thus aid in the understanding of one or more embodiments of the invention, the foregoing description of the embodiments of this application sometimes combines multiple features into one embodiment or its description. However, this disclosure method does not imply that the subject matter of this application requires more features than those mentioned in the claims. In fact, the embodiments have fewer features than all the features of the single embodiments disclosed above.

[0086] Finally, it should be understood that the embodiments described in this application are merely illustrative of the principles of the embodiments of this application. Other modifications may also fall within the scope of this application. Therefore, alternative configurations of the embodiments of this application are considered as examples and not limitations, and are regarded as consistent with the teachings of this application. Accordingly, the embodiments of this application are not limited to the embodiments explicitly described and illustrated in this application.

Claims

1. An all-solid-state battery, characterized in that, include: A positive electrode, a solid electrolyte membrane, and a negative electrode are sequentially stacked; among them... The all-solid-state battery also includes a polymer frame that circumferentially covers the edge of the positive electrode active material layer of the positive electrode sheet and is at least partially covered by the solid electrolyte membrane. The side of the polymer frame that contacts the solid electrolyte membrane has a modified coating, which includes an ion-conducting material.

2. The all-solid-state battery according to claim 1, characterized in that, The ratio of the elastic modulus of the modified coating to the elastic modulus of the polymer frame is (10:1)-(500:1).

3. The all-solid-state battery according to claim 1, characterized in that, The modified coating has an ionic conductivity ≥ 1 x 10 -3 mS / cm at 25 °C.

4. The all-solid-state battery according to claim 1, characterized in that, The density of the modified coating is greater than 90%.

5. The all-solid-state battery according to claim 4, characterized in that, The ion-conducting material includes one or more of the oxygen-containing inorganic acid salts of lithium, and / or one or more of the thioinorganic acid salts of lithium.

6. The all-solid-state battery according to claim 1, characterized in that, The modified coating also includes a binder; the binder has a mass fraction of 10%-25%.

7. The all-solid-state battery according to claim 1, characterized in that, The thickness of the polymer frame is 160μm-250μm; the thickness of the modified coating is 100nm-300nm.

8. The all-solid-state battery according to claim 1, characterized in that, The solid electrolyte membrane includes one or more of the following: sulfide solid electrolyte, halide solid electrolyte, oxide solid electrolyte, and boride solid electrolyte.

9. A method for preparing an all-solid-state battery as described in any one of claims 1-8, characterized in that, The preparation method includes: S1. Provide a polymer frame and prepare a modified coating on one side of the polymer frame in the thickness direction to obtain a composite frame; S2. Provide a positive electrode sheet and assemble the positive electrode sheet with the composite frame to obtain a composite positive electrode sheet; wherein the composite frame circumferentially covers the edge of the positive active material layer of the positive electrode sheet; S3. Provide a negative electrode sheet and a solid electrolyte membrane, and stack and assemble the composite positive electrode sheet, the solid electrolyte membrane and the negative electrode sheet in sequence to obtain the all-solid-state battery; In the composite positive electrode sheet, the modified coating of the composite frame is in at least partial contact with the solid electrolyte membrane.

10. The method for preparing an all-solid-state battery according to claim 9, characterized in that, The modified coating in step S1 is prepared using atomic layer deposition or magnetron sputtering.

Images