An anode sheet and application thereof

Abstract

The application relates to a negative electrode sheet and application thereof, and the negative electrode sheet comprises a negative electrode current collector, a composite active layer located on at least one side of the negative electrode current collector, a protective film located on the side of the composite active layer away from the negative electrode current collector, and a passivation layer located between the negative electrode current collector and the composite active layer; the composite active layer comprises a three-dimensional skeleton with holes and a liquid alloy filled in part of the holes of the three-dimensional skeleton; the three-dimensional skeleton has a resilience rate of greater than or equal to 80%, and an average pore size of 100-200 nm; the liquid alloy has a melting point of less than or equal to 25 DEG C; the protective film comprises zero-dimensional nanocarbon materials and lithium diffusion materials; and the initial density of the protective film is greater than or equal to 85%. The negative electrode sheet has low volume expansion, the corrosion degree of the negative electrode current collector is low, and the creep of the material can be controlled to be Coble creep controlled by grain boundary diffusion, so that the cycle performance and safety of a corresponding solid-state battery are comprehensively improved.

Description

Technical Field

[0001] This invention relates to the field of secondary battery technology, specifically to a negative electrode sheet and its application. Background Technology

[0002] With increasing user demands for higher capacity and faster charging performance in portable electronic devices, all-solid-state batteries have become a key direction in the development of rechargeable batteries. Compared to liquid batteries using electrolytes, all-solid-state batteries offer higher theoretical capacity, faster charging performance, and improved theoretical safety. An all-solid-state battery consists of a positive electrode, a negative electrode, and a solid electrolyte membrane. The positive and negative electrodes each include a current collector and either the positive or negative electrode material located on the surface of the current collector. Among the negative electrode materials for all-solid-state batteries, lithium metal anode materials possess extremely high theoretical specific capacity (3860 mAh / g) and the lowest electrochemical potential (-3.04 V vs. SHE), making them considered ideal anode materials for achieving high-energy-density batteries.

[0003] However, lithium metal anode materials face numerous technical challenges in practical applications, limiting their large-scale commercial use. First, lithium metal anode materials undergo approximately 100% volume change during charge and discharge, which loosens the interface between the anode and the solid electrolyte membrane, leading to poor contact and a continuous increase in interfacial impedance. Second, using lithium metal anode materials makes it easier for lithium dendrites to form in solid-state batteries during charge and discharge. These dendrites can penetrate the solid electrolyte, posing a short-circuit risk. Third, side reactions can occur when lithium metal anode materials come into contact with the solid electrolyte membrane, resulting in a high-impedance interfacial layer. Finally, lithium metal anode materials undergo a solid-liquid transition during charge and discharge. Prolonged contact between liquid or semi-liquid lithium metal and the current collector can corrode the current collector, damaging the anode structure and affecting the cycle stability of the solid-state battery. Summary of the Invention

[0004] One objective of this invention is to provide a negative electrode sheet to solve the problems in the prior art, such as negative electrode volume expansion, corrosion of the negative electrode current collector, and the decrease in cycle stability caused by side reactions at the interface between the negative electrode and the solid electrolyte membrane, as well as the risk of short circuit caused by excessive lithium dendrite formation, when lithium metal is used as the negative electrode material. Another objective is to provide a solid-state battery. A third objective is to provide an electrical device.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows: In a first aspect, the present invention provides a negative electrode sheet, comprising a negative electrode current collector, a composite active layer located on at least one side of the negative electrode current collector, a protective film located on the side of the composite active layer away from the negative electrode current collector, and a passivation layer located between the negative electrode current collector and the composite active layer. The composite active layer includes a three-dimensional skeleton with pores, and a liquid alloy filling at least a portion of the pores of the three-dimensional skeleton; The three-dimensional skeleton has a resilience of ≥80% and an average pore size of 100~200nm; The melting point of the liquid alloy is ≤25℃; The protective film comprises zero-dimensional nano-carbon materials and lithium diffusion materials; The initial density of the protective film is ≥85%.

[0006] The rebound rate test method for the negative electrode sheet provided by this invention is as follows: the initial thickness of the three-dimensional skeleton is H1; a pressure of 50 MPa is applied to the three-dimensional skeleton and maintained for 10 minutes; the pressure is then released, and the sheet is left to stand for 10 minutes. The thickness of the three-dimensional skeleton after the standing period is H2. The rebound rate is calculated as H2 / H1 × 100%. The initial density of the protective film refers to the density of the protective film before the negative electrode sheet is connected to the battery and undergoes its first charge.

[0007] In one alternative implementation, ≥80% of the pore volume in the three-dimensional skeleton is contributed by pore sizes in the range of 100 to 200 nm.

[0008] In one optional embodiment, the thickness of the negative electrode sheet is 25~60μm.

[0009] In one optional embodiment, the thickness of the negative electrode current collector is 4~12μm.

[0010] In one alternative embodiment, the thickness of the passivation layer is 50~200nm.

[0011] In one optional embodiment, the thickness of the composite active layer is 20~50μm.

[0012] In one optional embodiment, the thickness of the protective film is 1~8 μm; in a further optional embodiment, the thickness of the protective film is 1~5 μm.

[0013] In one optional implementation, the negative electrode sheet satisfies at least one of the following conditions: (1) The raw materials of the three-dimensional skeleton include nano-conductive fibers and a first adhesive; (2) The porosity of the three-dimensional skeleton is 80%~90%, and the density is 1~150 mg / cm³. 3 ; (3) The pore size distribution of the three-dimensional skeleton conforms to the relationship 1: (D90-D10) / D50≤0.8; where D10 is the pore size value corresponding to the cumulative pore volume in the three-dimensional skeleton reaching 10%; D50 is the median of the pore size distribution, which is the pore size value corresponding to the cumulative pore volume in the three-dimensional skeleton reaching 50%; D90 is the pore size value corresponding to the cumulative pore volume in the three-dimensional skeleton reaching 90%; for specific data, refer to GB / T 21650.1-2008 and use mercury intrusion porosimetry (MIP) for testing; (4) The initial compression rate of the three-dimensional skeleton is 50%~90%; the test method for the initial compression rate is as follows: the original thickness of the three-dimensional skeleton is H1, a pressure of 50MPa is applied to the three-dimensional skeleton and held for 10min, and the thickness of the three-dimensional skeleton at this time is H3. The initial compression rate = H3 / H1×100%; (5) The area fractal dimension D of the three-dimensional skeleton f The area fractal dimension is 2.2~2.8. The area fractal dimension reflects the scaling relationship between pore size and pore number. The testing method involves taking a three-dimensional skeleton sample and capturing a secondary electron image of the skeleton surface using a field emission scanning electron microscope (SEM) at 10000× magnification. The acquired SEM image is imported into image processing software, where grayscale conversion, contrast enhancement, and Gaussian filtering are performed sequentially. Then, the image is binarized using the Otsu automatic thresholding method, making the pore areas black and the solid areas white, resulting in a binarized image. The area fractal dimension Df is calculated using the box-counting method: the binarized image is covered with square grids with side lengths of 4, 8, 16, 32, 64, 128, and 256 pixels. The number of grids containing pore pixels at each size, N(ε), is counted, where ε is the ratio of the grid side length to the image side length. A linear fit is performed between lnN(ε) and ln(1 / ε), and the slope of the fitted line is the area fractal dimension Df. (6) The surface of the three-dimensional framework is connected with at least one of the functional groups -COOH, -OH, and -NH2, and / or, the I of the three-dimensional framework D / I G The value is 1.2~2.0; In the negative electrode sheet provided by this invention, I D This indicates that the Raman spectrum is at 1350±50 cm⁻¹. -1 D peak intensity at I G This indicates that the Raman spectrum is at 1580±50 cm⁻¹. -1 The intensity of the G peak at the location; during the test, a portion of the prepared three-dimensional skeleton was used for Raman testing; (7) The liquid alloy comprises the following components by weight percentage: Ga: 60%~80%, In: 9%~22%, Sn: 5%~18%, Bi: 1%~5%, Zn: 0~5%; (8) The apparent lithium diffusion coefficient of the liquid alloy is 4 × 10⁻⁶. -10 m 2 / s~1×10 -7 m 2 / s; (9) It also includes an encapsulation ring, which is located on the surface of the passivation layer away from the negative electrode current collector; it is continuously distributed along the edge of the passivation layer to form a closed structure; (10) The protective film also includes a second adhesive.

[0014] In one optional embodiment, the conductive nanofiber includes at least one of single-walled carbon nanotubes, carbon nanofibers, graphene fibers, and conductive polymer fibers.

[0015] In one optional embodiment, the conductive nanofiber has a length of 2~100μm and a diameter of 2~200nm.

[0016] In one alternative embodiment, the first adhesive comprises at least one of polyacrylic acid, polyurethane, polyvinylidene fluoride, and polyacrylonitrile.

[0017] In one optional embodiment, the mass ratio of the nano-conductive fibers to the first adhesive in the raw materials of the three-dimensional skeleton is 6~9:1~4.

[0018] In one optional embodiment, in the composite active layer, with the porosity of the three-dimensional skeleton being 100%, the filling rate of the liquid alloy is 50%~80%. The filling rate of the liquid alloy is calculated as follows: The mass of the three-dimensional skeleton, W1, is weighed, and the overall mass of the product after filling with the liquid alloy, W2, is weighed; the total volume of the three-dimensional skeleton is measured and calculated, and the pore volume V1 is calculated as the total volume of the three-dimensional skeleton × the porosity of the three-dimensional skeleton; the density of the liquid alloy at room temperature, ρ1, is measured using a conventional density testing method; the three-dimensional skeleton is subjected to a loading pressure of 2MPa, a loading speed of 5mm / min, a holding pressure of 1min, and an unloading rate of 5mm / min for 100 cycles, and the average compression ratio R1 is recorded; the filling rate of the liquid alloy is calculated as (W2-W1) / (V1×ρ1×R1)×100%. When calculating the filling rate, considering that the composite active layer is mostly under pressure during actual preparation and use, the average compression ratio is introduced as an adjustment.

[0019] In one optional embodiment, in the composite active layer, the static contact angle θ between the three-dimensional skeleton and the liquid alloy is less than 30°, and the dynamic wetting time is less than 30s.

[0020] In one optional embodiment, when the surface of the three-dimensional skeleton is connected with at least one of the functional groups -COOH and -OH, the molar ratio of oxygen atoms to carbon atoms on the surface of the three-dimensional skeleton is O / C 0.10~0.35.

[0021] In one optional embodiment, when the surface of the three-dimensional framework is connected with the functional group -NH2, the molar ratio of nitrogen atoms to carbon atoms on the surface of the three-dimensional framework is N / C, which is 0.05~0.15.

[0022] The percentages of oxygen and carbon atoms on the surface of the three-dimensional framework, and the percentages of nitrogen and carbon atoms on the surface of the three-dimensional framework, were determined by X-ray photoelectron spectroscopy (XPS).

[0023] In one alternative embodiment, the three-dimensional skeleton has a static contact angle θ with the liquid alloy. scaffold <The static contact angle θ of the protective film with the liquid alloy> protection <The static contact angle θ of the passivation layer with respect to the liquid alloy> passivation The method for testing static contact angle includes adding 10 μL of liquid alloy to a three-dimensional skeleton, protective film, or passivation layer at room temperature, and measuring the static contact angle at room temperature using a contact angle measuring instrument within 10 seconds after the droplet stabilizes.

[0024] In one optional embodiment, the areal loading of the liquid alloy in the negative electrode sheet is 0.1~2 mg / cm². 2 .

[0025] In one optional embodiment, the encapsulation ring has a thickness of 40% to 60% of the composite active layer thickness and a width of 0.005% to 0.05% of the short side length of the negative electrode current collector.

[0026] In one alternative embodiment, the surface energy of the encapsulating ring material is ≤26mN / m.

[0027] In one alternative embodiment, the material of the encapsulating ring has a static contact angle θ with the liquid alloy. edge The static contact angle is 120°~150°. The test method for the static contact angle includes adding 10 μL of liquid alloy to the material of the encapsulating ring at room temperature, and measuring the static contact angle at room temperature using a contact angle measuring instrument within 10 seconds after the droplet stabilizes.

[0028] In one alternative embodiment, the encapsulating ring is made of at least one of polytetrafluoroethylene, polyvinylidene fluoride, and fluorinated ethylene propylene copolymer.

[0029] In one alternative embodiment, the lithium diffusion material is dispersed in the protective film as lithium diffusion material particles.

[0030] In one optional embodiment, the lithium diffusion material serves as a coating layer in the protective film, coating at least a portion of the surface of the zero-dimensional carbon nanomaterial. In a further optional embodiment, when the lithium diffusion material serves as a coating layer coating at least a portion of the surface of the zero-dimensional carbon nanomaterial, the thickness of the coating layer is 1~20 nm.

[0031] In one optional embodiment, the protective film comprises, by mass percentage: 10% to 90% zero-dimensional nano-carbon material, 1% to 89% lithium diffusion material, and 1% to 30% second adhesive.

[0032] In one optional embodiment, the particle size D50 of the zero-dimensional carbon nanomaterial is 5~50 nm.

[0033] In one optional embodiment, the particle size D50 of the lithium diffusion material particles is 1~50nm.

[0034] In one alternative embodiment, the zero-dimensional carbon nanomaterial includes at least one of conductive carbon black, carbon quantum dots, fullerene, and carbon nano-onion.

[0035] In one optional embodiment, the lithium diffusion material comprises at least one of a metal nitride, a metal phosphide, and a metal halide. The lithium diffusion material undergoes in-situ transformation during the first charge, such as the in-situ transformation of metal nitride into lithium nitride and a corresponding metal or a lithium-containing alloy of the corresponding metal, the in-situ transformation of metal phosphide into lithium phosphide and a corresponding metal or a lithium-containing alloy of the corresponding metal, and the in-situ transformation of metal halide into lithium halide and a corresponding metal or a lithium-containing alloy of the corresponding metal. The lithium-ion conductivity of the material generated after the transformation should be ≥10. -2 mS / cm.

[0036] In one alternative embodiment, the second adhesive comprises an organic polymer adhesive.

[0037] In one optional embodiment, the protective film comprises, by weight percentage: 30% to 60% zero-dimensional nano-carbon material, 35% to 65% lithium diffusion material, and 5% to 15% second adhesive.

[0038] In one alternative embodiment, the metal in the metal nitride, metal phosphide, and metal halide is each independently selected from at least one of lithium, aluminum, magnesium, tin, zinc, niobium, iron, manganese, copper, indium, bismuth, antimony, and lanthanum.

[0039] In one alternative embodiment, the organic polymer adhesive includes at least one of polyvinylidene fluoride, polyvinylidene fluoride-hexafluoropropylene copolymer, polyethylene oxide, polyacrylonitrile, polymethyl methacrylate, and polystyrene.

[0040] In one optional embodiment, the surface resistivity of the passivation layer is <10Ω / sq; in a further optional embodiment, the surface resistivity of the passivation layer is <5Ω / sq; the surface resistivity is measured using the four-probe method in accordance with GB / T40007-2021.

[0041] In one optional embodiment, the texture factor of the lowest surface energy crystal plane in the passivation layer is 1.5 to 4.0; in a further optional embodiment, the texture factor of the lowest surface energy crystal plane in the passivation layer is 2.5 to 4.0. The lowest surface energy crystal plane refers to the crystal plane with the lowest surface energy value among all exposed crystal planes of a crystal; the texture factor of the lowest surface energy crystal plane is obtained by collecting diffraction peaks and intensity data in the passivation layer using XRD (X-ray diffraction) and calculating it.

[0042] In one optional embodiment, the material of the negative electrode current collector includes at least one of copper-based materials, iron-carbon-based materials, nickel-based materials, and titanium-based materials.

[0043] In one alternative embodiment, the material of the passivation layer includes at least one of Mo, W, Ta, TiN, and MAX phase materials.

[0044] In one optional embodiment, the negative electrode current collector includes at least one of copper foil, stainless steel foil, nickel foil, and titanium foil.

[0045] In one alternative embodiment, the MAX phase material includes at least one of Ti3AlC2 and Cr2AlC.

[0046] In a second aspect, the present invention provides a solid-state battery, including the above-mentioned negative electrode sheet, and also including a positive electrode sheet and a solid electrolyte membrane.

[0047] In the solid-state battery provided by this invention, the positive electrode sheet and the solid electrolyte membrane can be conventional products in the art. The positive electrode sheet includes a positive current collector and a positive active material layer located on at least a portion of the surface of the positive current collector. The positive active material layer includes a positive active material, a solid electrolyte, a conductive agent, and a binder. The solid electrolyte membrane includes a solid electrolyte and a binder. Typically, but not limited to, the positive active material includes at least one of layered oxide-based materials, lithium-rich manganese-based materials, polyanionic materials, and spinel-type materials, such as specifically including at least one of nickel-cobalt-manganese ternary materials, nickel-cobalt-aluminum ternary materials, nickel-iron-manganese ternary materials, lithium manganese oxide materials, and lithium iron phosphate materials. The solid electrolyte particles include at least one of sulfide solid electrolyte particles, oxide solid electrolyte particles, and halide solid electrolyte particles. The conductive agent includes at least one of conductive graphite, carbon nanotubes, Ketjen black, graphene, conductive carbon black, and acetylene black. The binder includes at least one of polytetrafluoroethylene, polyvinylidene fluoride, polyacrylic acid, polyvinyl alcohol, and polyisobutylene.

[0048] In one optional embodiment, the ratio of the long side length of the solid electrolyte membrane and the negative electrode sheet is 1.05~1.5:1, and the ratio of the short side length is 1.05~1.5:1.

[0049] In one optional embodiment, the ratio of the length of the long side of the negative electrode and the positive electrode is 1.05 to 1.5:1, and the ratio of the length of the short side is 1.05 to 1.5:1.

[0050] In one optional embodiment, during the charging and discharging process of the solid-state battery, when charged to above 20% SOC, the liquid alloy solidifies and transforms into alloy grains; when discharged to below 20% SOC, the alloy grains liquefy and transform into liquid alloy. The alloy grains conform to equation 2: ψ=D 3 / (λ·d·N 2 / 3 ), 1.5≤ψ≤2.0; In Equation 2, ψ is a characteristic parameter of Kober creep; D is the numerical value of the average alloy grain size, and the unit of the average alloy grain size is nm; λ is the value of the average alloy grain spacing, and the unit of the average alloy grain spacing is nm; d is the numerical value of the alloy grain boundary width, and the unit of the alloy grain boundary width is nm; N is the numerical value of the number of alloy grains per unit volume, and the unit of the number of alloy grains per unit volume is grains / μm. 3 .

[0051] In one optional embodiment, when the solid-state battery is first charged to above 20% SOC, the average alloy grain size is ≤80nm and the standard deviation of the alloy grain size distribution is ≤15nm.

[0052] In the solid-state battery provided by this invention, after assembling the negative electrode sheet into an all-solid-state battery, the charging and discharging current density is 0.1C. After charging and discharging to the required charge state, the negative electrode sheet is disassembled in an inert atmosphere glove box and removed. Electron backscatter diffraction (EBSD) is used to analyze the cross-section of the negative electrode, counting at least 200 alloy grains, measuring the alloy grain size, and calculating the average alloy grain size D (nm) and the standard deviation of the alloy grain size distribution σ (nm). Based on the EBSD images, image processing software (ImageJ) is used to measure the average distance between adjacent alloy grains, i.e., the average alloy grain spacing λ (nm), and the shortest distance between alloy grain boundaries is taken. High-resolution transmission electron microscopy (HRTEM) is used to capture high-resolution images in the alloy grain boundary region, measuring the width of the disordered layer of the alloy grain boundary, i.e., the alloy grain boundary width d (nm), and the average value is taken from at least 10 different alloy grain boundary locations. Based on the EBSD analysis data, the alloy grains are counted, and the number of alloy grains per unit volume N (number / μm) is calculated. 3 At least 10 different regions' fields of view were statistically analyzed, and the average value was taken.

[0053] In one optional embodiment, the initial density of the protective film is D1, and the density of the protective film after the first charge of the solid-state battery is D2, where D2 ≥ 92% and D2 - D1 ≥ 5%.

[0054] In one alternative embodiment, the solid-state battery satisfies relation 3: 1.25 ≤ D pore / D≤2.5; where D pore The average pore size is the numerical value of the three-dimensional skeleton, and the unit of the average pore size is nm.

[0055] In one alternative implementation, the solid-state battery satisfies relation 4: V expansion × (1-R initial )≤P scaffold ×0.7; where V expansion R is the volume expansion rate of the liquid alloy after it is fully filled. initial P is the initial compression ratio of the 3D skeleton. scaffold Porosity of the three-dimensional framework. Volume expansion rate V of the liquid alloy after full filling. expansion The testing method involves constructing an all-solid-state mold battery, with the negative electrode consisting only of liquid alloy and the counter electrode being a lithium sheet. After full charging, the battery is disassembled, the volume of the liquid alloy after full charging is measured, and the volume expansion rate is further calculated.

[0056] In one optional embodiment, the fully charged solid-state battery satisfies the following: the elastic modulus E of the composite active layer after full charging. active The elastic modulus E of the protective film after it is fully filled protection The elastic modulus E after the passivation layer is fully filled passivation Elastic modulus. After fully charging the solid-state battery, it was disassembled, and the elastic modulus of the passivation layer, composite active layer, and protective film after full charging was tested using a nanoindenter. The unit is MPa.

[0057] Thirdly, the present invention provides an electrical device including the above-mentioned solid-state battery, wherein the solid-state battery serves as the power supply for the electrical device.

[0058] The beneficial effects of this invention are: (1) The negative electrode sheet provided by the present invention includes a negative current collector, a composite active layer located on at least one side of the negative current collector, a protective film located on the side of the composite active layer away from the negative current collector, and a passivation layer located between the negative current collector and the composite active layer; the composite active layer includes a three-dimensional skeleton with pores, and a liquid alloy filling at least part of the pores of the three-dimensional skeleton; the resilience of the three-dimensional skeleton is ≥80%, and the average pore size is 100~200nm; the melting point of the liquid alloy is ≤25℃; the protective film includes zero-dimensional nano-carbon material and lithium diffusion material; the initial density of the protective film is ≥85%. The negative electrode sheet provided by this invention can reduce the volume expansion of the negative electrode sheet and the degree of corrosion of the negative electrode current collector, prevent the overflow of liquid alloy, avoid excessive side reactions at the interface between the negative electrode material and the solid electrolyte membrane, prevent excessive growth of lithium dendrites, and control the creep of lithium metal to Coble creep controlled by grain boundary diffusion, thereby comprehensively improving the cycle performance and safety of the corresponding solid-state battery.

[0059] In the composite active layer, a dynamic adaptive lithium alloy composite framework is formed by a three-dimensional framework with a resilience of ≥80% and a liquid alloy with a melting point ≤25℃. During charging, the liquid alloy transforms into a solid lithium-containing alloy, and the three-dimensional framework is compressed synchronously with lithium deposition. During discharging, the solid lithium-containing alloy transforms back into a liquid alloy, and the three-dimensional framework actively rebounds, achieving dynamic buffering of volumetric strain. Simultaneously, the specific average pore size of 100~200nm in the three-dimensional framework, combined with the liquid alloy, induces the lithium alloy to transform from a liquid to a solid lithium-containing alloy. The grain size of the lithium-containing alloy is less than 100nm, causing the lithium metal creep mechanism to be dominated by Coble creep controlled by grain boundary diffusion rather than dislocation creep. Furthermore, this prevents mechanical damage between the interfaces of the layers during the charge-discharge cycles of the solid-state battery. Furthermore, during charging, the liquid alloy transforms into a solid lithium-containing alloy, preventing leakage due to expansion and compression that could lead to a short circuit and improve safety. During discharging, the alloy reverts to a liquid state, automatically filling the interfacial voids caused by volume contraction. A passivation layer is placed between the negative electrode current collector and the composite active layer to prevent excessive corrosion of the negative electrode current collector by the liquid alloy. The protective film physically isolates the liquid alloy from the solid electrolyte membrane, significantly reducing the generation of side reactions at this interface and preventing potential lithium dendrites from penetrating the solid electrolyte membrane, thus improving the safety of the corresponding solid-state battery. Moreover, the lithium diffusion material in the protective film undergoes in-situ transformation during battery charging, exhibiting rapid lithium conduction characteristics and volume expansion after transformation, increasing the density of the insulating layer.

[0060] (2) In the negative electrode sheet provided by the present invention, the thickness of the negative electrode sheet is 25~60μm; the thickness of the negative current collector is 4~12μm; the thickness of the passivation layer is 50~200nm; the thickness of the composite active layer is 20~50μm; and the thickness of the protective film is 1~5μm. Reasonable thickness settings for each layer facilitate better coordination between them, thereby further improving the performance of the corresponding solid-state battery.

[0061] (3) In the negative electrode sheet provided by the present invention, the porosity of the three-dimensional skeleton is 80%~90%, and the density is 1~150 mg / cm³. 3 Within this porosity and density range, the three-dimensional framework provides ample lithium storage space to accommodate volume expansion while maintaining sufficient mechanical strength to support multiple compression-rebound cycles, further preventing structural collapse. Simultaneously, the low-density characteristics reduce the inactive mass of the electrodes, which is beneficial for improving the overall energy density of the battery.

[0062] (4) In the negative electrode sheet provided by the present invention, the initial compression ratio of the three-dimensional skeleton is 50%~90%. This initial compression ratio range works synergistically with the rebound rate ≥80%, enabling the three-dimensional skeleton to actively compress and absorb volume expansion during charging with lithium deposition, and actively rebound to maintain interface contact during discharging. If the initial compression ratio is below 50%, the buffering capacity is insufficient; if it is above 90%, the skeleton structure may be damaged, and liquid alloy retention cannot be achieved; the compression ratio range of 50%~90% further ensures cycle stability.

[0063] (5) In the negative electrode sheet provided by the present invention, the area fractal dimension D of the three-dimensional skeleton is... f The value is 2.2~2.8; it can further reduce the local stress accumulation caused by uneven pore volume.

[0064] (6) In the negative electrode sheet provided by the present invention, the surface of the three-dimensional framework is connected with at least one of the functional groups -COOH, -OH, and -NH2, and / or, the I of the three-dimensional framework D / I G ≥1.2. I D / I G ≥1.2 indicates that there are certain defects on the surface of the three-dimensional skeleton. By connecting functional groups to the surface of the three-dimensional skeleton and / or making its surface have certain defects, the affinity between the three-dimensional skeleton and the liquid alloy can be further improved, thereby improving the interlayer bonding strength and further improving the stability of the structure.

[0065] (7) In the negative electrode sheet provided by the present invention, the liquid alloy comprises the following components by weight percentage: Ga: 60%~80%, In: 9%~22%, Sn: 5%~18%, Bi: 1%~5%, Zn: 0~5%. A reasonable liquid alloy composition ratio can further enable the lithium metal creep to be dominated by Coble creep controlled by grain boundary diffusion, thereby improving the stability of the structure.

[0066] (8) In the negative electrode sheet provided by the present invention, the composite active layer has a porosity of 100% for the three-dimensional skeleton and a filling rate of 50% to 80% for the liquid alloy. The reasonable amount of three-dimensional skeleton and liquid alloy in the composite active layer can further enhance the dynamic buffering effect of the composite active layer on volumetric strain.

[0067] (9) In the negative electrode sheet provided by the present invention, the static contact angle between the three-dimensional skeleton and the liquid alloy in the composite active layer is <30°, and the dynamic wetting time is <30s. This is beneficial for the timely adaptation of the three-dimensional skeleton during the solid-liquid transition process of the liquid alloy, and can further improve the stability of the structure.

[0068] (10) In the negative electrode sheet provided by the present invention, the areal loading of the liquid alloy is 0.1~2 mg / cm³.2 A reasonable liquid alloy surface load can provide a more reasonable battery capacity.

[0069] (11) The negative electrode sheet provided by the present invention further includes an encapsulation ring, which is located on the surface of the passivation layer away from the negative electrode current collector; it is continuously distributed along the edge of the passivation layer to form a closed structure. The encapsulation ring can confine the liquid alloy within the vertical projection area of ​​the three-dimensional skeleton during the compression-springback process caused by the charging and discharging process of the negative electrode sheet, effectively preventing the liquid alloy from overflowing due to lateral creep or agglomeration on the surface of the passivation layer during ultra-long-term cycling or high-temperature cycling.

[0070] (12) In the negative electrode sheet provided by the present invention, the lithium diffusion material can be dispersed in the protective film as lithium diffusion material particles; or it can be used as a coating layer to coat at least a portion of the surface of the zero-dimensional carbon nanomaterial. When the lithium diffusion material is dispersed in the protective film as lithium diffusion material particles, it can further ensure the uniformity of the in-situ conversion reaction of the lithium diffusion material during charging, forming a more uniform three-dimensional ion-conducting network. When the lithium diffusion material is used as a coating layer to coat at least a portion of the surface of the zero-dimensional carbon nanomaterial, the high electronic conductivity of the zero-dimensional carbon nanomaterial and the volume expansion of the products of the in-situ conversion reaction of the lithium diffusion material during charging can further improve the densification of the protective film, thereby improving the resistance to lithium dendrite puncture.

[0071] (13) In the negative electrode sheet provided by the present invention, the protective film comprises, by mass percentage: 10%~90% zero-dimensional nano-carbon material, 1%~89% lithium diffusion material, and 1%~30% second binder. The reasonable composition of each raw material in the protective film is more conducive to improving the density of the protective film.

[0072] (14) In the negative electrode sheet provided by the present invention, the lithium diffusion material includes at least one of metal nitride, metal phosphide, and metal halide. The lithium diffusion material reacts with lithium metal in situ during the first charge and discharge process to generate lithium nitride, lithium phosphide, or lithium halide, and has rapid lithium conduction characteristics after the reaction, which can improve the conductivity of the protective film.

[0073] (15) In the negative electrode sheet provided by the present invention, the static contact angle θ of the three-dimensional skeleton with the liquid alloy scaffold <The static contact angle θ of the protective film with the liquid alloy> protection <The static contact angle θ of the passivation layer with respect to the liquid alloy> passivation The static contact angle θ between the material of the encapsulating ring and the liquid alloy. edgeThe range is 120° to 150°. The wettability gradient and the static contact angle of the encapsulating ring material make the liquid alloy more inclined to remain on the three-dimensional skeleton side. The difference in wettability between the three layers is used to achieve self-confined domain of the liquid alloy. It can prevent the liquid alloy from migrating to the protective film side and the passivation layer side without additional physical barriers. This fundamentally solves the risk of short circuit caused by liquid alloy leakage and avoids leakage and side reactions.

[0074] (16) The solid-state battery provided by the present invention includes the above-mentioned negative electrode sheet, as well as a positive electrode sheet and a solid electrolyte membrane. The solid-state battery has good cycle performance and safety performance.

[0075] (17) In the solid-state battery provided by the present invention, the ratio of the long side length of the solid electrolyte membrane and the negative electrode sheet is 1.05~1.5:1, and the ratio of the short side length is 1.05~1.5:1; the ratio of the long side length of the negative electrode sheet and the positive electrode sheet is 1.05~1.5:1, and the ratio of the short side length is 1.05~1.5:1. By limiting the length and width gradient relationship of the solid electrolyte membrane, the negative electrode sheet, and the positive electrode sheet, it is ensured that the edge of the positive electrode sheet is completely covered by the negative electrode sheet, and the edge of the negative electrode sheet is completely covered by the solid electrolyte membrane. This macroscopic size gradient design, in conjunction with the microscopic confinement structure of the encapsulation ring on the surface of the passivation layer, achieves dual confinement of lithium metal / liquid alloy at both macroscopic and microscopic scales: at the macroscopic level, it prevents the edge of the positive electrode from piercing the solid electrolyte layer and the uneven growth of lithium dendrites at the edge of the negative electrode; at the microscopic level, it prevents the lateral creep loss of the liquid alloy, thereby comprehensively improving the assembly yield, cycle safety, and structural stability of the all-solid-state battery.

[0076] (18) In the solid-state battery provided by the present invention, during the charging and discharging process, when charged to above 20% SOC, the liquid alloy solidifies and transforms into alloy grains; when discharged to below 20% SOC, the alloy grains liquefy and transform into liquid alloys; the alloy grains conform to relation 2: ψ=D 3 / (λ·d·N 2 / 3 ), 1.5≤ψ≤2.0; In Equation 2, ψ is the characteristic parameter of Kober creep; D is the average alloy grain size, in nm; λ is the average alloy grain spacing, in nm; d is the alloy grain boundary width, in nm; N is the number of alloy grains per unit volume, in units / μm. 3 The provisions of Equation 2 further satisfy the requirement that Coble creep plays a major diffusion role in the solid-state battery.

[0077] (19) The solid-state battery provided by the present invention satisfies relation 3: 1.25≤D pore / D≤2.5; where Dpore Let be the average pore size of the three-dimensional framework, with the unit of average pore size being nm. Satisfying Equation 3 ensures that the pore size and grain size are on the same order of magnitude, the grain boundary diffusion channels remain continuous in three-dimensional space, and Coble creep occurs effectively; deviating from this ratio range, the Coble creep efficiency drops sharply.

[0078] (20) The solid-state battery provided by the present invention satisfies relation 4: V expansion × (1-R initial )≤P scaffold ×0.7; where V expansion R is the volume expansion rate of the liquid alloy after it is fully filled. initial P is the initial compression ratio of the 3D skeleton. scaffold Let represent the porosity of the three-dimensional framework. Satisfying Equation 4 ensures that the total volume of the liquid alloy after lithiation and expansion does not exceed the capacity of the framework pores, thus preventing the liquid alloy from overflowing the framework due to volume expansion during cycling.

[0079] (21) The solid-state battery provided by the present invention satisfies the following after full charging: the elastic modulus E of the composite active layer after full charging active The elastic modulus E of the protective film after it is fully filled protection The elastic modulus E after the passivation layer is fully filled passivation The elastic modulus gradient buffers stress progressively as it is transferred from the active layer to the current collector. The composite active layer (soft) deforms first to absorb most of the energy, the protective film (medium modulus) further buffers the stress, and the passivation layer (hard) ultimately bears the load. This gradient design avoids stress concentration at a single interface, preventing stress concentration at a particular interface from causing cracking. Attached Figure Description

[0080] Figure 1 This is a schematic image of the negative electrode sheet in Embodiment 1 of the present invention; Figure 2 This is a schematic diagram of the structure of a solid-state battery made using the negative electrode sheet provided in Example 1 of the present invention, as shown in the test example of the present invention. Figure 3 These are cycle performance images of Embodiment 2 and Comparative Example 6 of the present invention.

[0081] Among them, 1-negative electrode current collector; 2-passivation layer; 3-composite active layer; 301-liquid alloy; 302-three-dimensional skeleton; 4-protective film; 5-solid electrolyte film; 6-positive electrode active layer; 7-positive electrode current collector; 8-encapsulation ring. Detailed Implementation

[0082] The embodiments of the present invention will be described below with reference to the accompanying drawings and preferred embodiments. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention. It should be understood that the preferred embodiments are only for illustrating the present invention and not for limiting the scope of protection of the present invention.

[0083] It should be noted that the illustrations provided in the following embodiments are only schematic representations of the basic concept of the present invention. Therefore, the drawings only show the components related to the present invention and are not drawn according to the actual number, shape and size of the components in the actual implementation. In the actual implementation, the form, quantity and proportion of each component can be arbitrarily changed, and the layout of the components may also be more complex.

[0084] For experiments not specifically described in the examples, the procedures or conditions should be followed according to the conventional experimental procedures described in the literature in this field. Reagents or instruments whose manufacturers are not specified are all commercially available conventional reagent products.

[0085] Test methods In a specific embodiment of the present invention, the performance parameters tested are performed using the following method: Surface resistivity of passivation layer: The surface resistivity of passivation layer was determined using the four-probe method, referring to GB / T40007-2021.

[0086] Texture coefficient of the lowest surface energy crystal plane of the passivation layer: The texture coefficient of the lowest surface energy crystal plane is calculated by collecting diffraction peaks and intensity data in the passivation layer through XRD (X-ray diffraction).

[0087] Percentage of atoms on the surface of the three-dimensional framework: determined by X-ray photoelectron spectroscopy (XPS).

[0088] Porosity and average pore size of the three-dimensional skeleton: Referring to GB / T 21650.1-2008, the porosity, average pore size, and pore size distribution of the three-dimensional skeleton were tested using the mercury intrusion porosimetry (MIP) method. The pore sizes D10, D50, and D90 of the three-dimensional skeleton were measured; and the value of (D90-D10) / D50 was further calculated.

[0089] Fractal dimension of the 3D skeleton: Using the 3D skeleton samples obtained in the examples and comparative examples, secondary electron images of the skeleton surface were captured using a field emission scanning electron microscope (SEM) at 10000× magnification. The acquired SEM images were imported into image processing software, and grayscale conversion, contrast enhancement, and Gaussian filtering noise reduction were performed sequentially. Then, the Otsu automatic thresholding method was used to binarize the image, making the pore areas black and the solid areas white, resulting in a binarized image. The area fractal dimension Df was calculated using the box-counting method: The binarized image was covered with square grids with side lengths of 4, 8, 16, 32, 64, 128, and 256 pixels. The number of grid pixels containing pores at each size, N(ε), was counted, where ε is the ratio of the grid side length to the image side length. A linear fit was performed between lnN(ε) and ln(1 / ε), and the slope of the fitted line is the area fractal dimension Df.

[0090] Compression and recovery performance of the three-dimensional skeleton: Dynamic mechanical analyzer (DMA) was used. The initial thickness of the three-dimensional skeleton was H1. A pressure of 50 MPa was applied to the skeleton and held for 10 min, at which point the thickness of the skeleton was measured as H3. The pressure was then removed, and the skeleton was allowed to stand for 10 min, at which point the thickness of the skeleton was measured as H2. The springback rate was calculated as H2 / H1 × 100%, and the initial compression rate was calculated as H3 / H1 × 100%. The three-dimensional skeleton was subjected to a loading pressure of 2 MPa, a loading speed of 5 mm / min, a holding pressure of 1 min, and an unloading speed of 5 mm / min for 100 cycles. The average compression rate and average springback rate were recorded. The structural retention rate after 100 cycles was calculated as the ratio of the final springback rate to the initial springback rate × 100%.

[0091] Wetting properties of the 3D framework with the liquid alloy: At room temperature, 10 μL of the liquid alloy used in the corresponding examples and comparative examples was dropped onto the 3D framework. Within 10 seconds after the droplet stabilized, the static contact angle was measured at room temperature using a contact angle measuring instrument. The time required for the liquid alloy to completely penetrate into the pores of the 3D framework was recorded as the dynamic wetting time. The wetting properties of other materials with the liquid alloy were similarly determined. 10 μL of the liquid alloy used in the corresponding examples and comparative examples was applied to the target material, and the static contact angle was measured at room temperature using a contact angle measuring instrument within 10 seconds after the droplet stabilized.

[0092] Melting point of liquid alloy: Differential scanning calorimetry (DSC) was used. 10 mg of alloy sample was weighed, sealed in an aluminum crucible, and heated from -60 °C to 100 °C at a rate of 5 °C / min under a nitrogen atmosphere. The endothermic peak onset temperature (extrapolated onset temperature) was recorded as the melting point.

[0093] Viscosity of liquid alloy: Using a rotational rheometer with a parallel plate fixture (25 mm in diameter), the shear rate ranged from 1 to 1000 s⁻¹ at the test temperature. -1Viscosity was measured internally, and the shear rate was recorded at 100 s. -1 Viscosity data at that time.

[0094] Apparent lithium diffusion coefficient of liquid alloy: Potentiostatic intermittent titration (PITT) was employed. A symmetrical battery was assembled (lithium metal sheet / composite active layer / lithium metal sheet), a 10mV potential step was applied, and the current decay curve over time was recorded. The apparent lithium diffusion coefficient D was calculated by fitting the current-time relationship. Li (m) 2 / s).

[0095] Surface load of liquid alloy: Calculated by weighing, the mass of a three-dimensional skeleton with a certain area A is M1, and the overall mass of the product after filling with liquid alloy with the same area A is M2. Surface load = (M2-M1) / A.

[0096] The filling rate of the liquid alloy is calculated by weighing. Weigh the mass W1 of the three-dimensional skeleton, weigh the overall mass W2 of the product after filling with liquid alloy, measure and calculate the total volume of the three-dimensional skeleton, and calculate the pore volume V1 of the skeleton as the total volume of the three-dimensional skeleton × the porosity of the three-dimensional skeleton. The density of the liquid alloy at room temperature is measured as ρ1 by conventional density testing methods. The average compression ratio R1 of the three-dimensional skeleton under a loading pressure of 2MPa is measured by the method given in the section on the compression and recovery performance of the three-dimensional skeleton. The filling rate of the liquid alloy is calculated as (W2-W1) / (V1×ρ1×R1)×100%.

[0097] Electronic conductivity of protective film: Cut the protective film into 2cm×2cm square samples, measure the resistivity at room temperature using a four-probe resistivity meter, record the resistivity values ​​at 5 different locations, take the average value as the resistivity, and calculate the electronic conductivity = 1 / resistivity. The unit of electronic conductivity is S / cm.

[0098] Ionic conductivity of the protective film: This was measured using electrochemical impedance spectroscopy (EIS). The protective film was sandwiched between two stainless steel blocking electrodes, assembling a blocking coin cell. Impedance spectra were measured at room temperature, in the frequency range of 0.1 Hz to 1 MHz, with an AC amplitude of 10 mV. Ionic conductivity σ = L / (R × S), where L is the thickness of the protective film, R is the real intercept of the impedance spectrum, and S is the electrode area.

[0099] Example 1 This embodiment provides a negative electrode plate, as described below. Figure 1 The negative electrode sheet provided in this embodiment will be described.

[0100] The negative electrode sheet provided in this embodiment includes a negative current collector 1, a composite active layer 3 located on at least one side of the negative current collector 1, a protective film 4 located on the side of the composite active layer 3 away from the negative current collector 1, and a passivation layer 2 located between the negative current collector 1 and the composite active layer 3; the composite active layer 3 includes a three-dimensional skeleton 302 with pores, and a liquid alloy 301 filling at least part of the pores of the three-dimensional skeleton 302; the resilience of the three-dimensional skeleton 302 is ≥80%, and the average pore size is 100~200nm; the melting point of the liquid alloy 301 is ≤25℃; the protective film 4 includes zero-dimensional nano-carbon material and lithium diffusion material; the initial density of the protective film 4 is ≥85%.

[0101] In some embodiments, the thickness of the negative electrode sheet is 25~60μm.

[0102] In some embodiments, the thickness of the negative electrode current collector 1 is 4~12μm.

[0103] In some embodiments, the thickness of the passivation layer 2 is 50~200nm.

[0104] In some embodiments, the thickness of the composite active layer 3 is 20~50μm.

[0105] In some embodiments, the thickness of the protective film 4 is 1~8 μm; in some embodiments, the thickness of the protective film 4 is 1~5 μm.

[0106] In some embodiments, the raw materials of the three-dimensional skeleton 302 include nano-conductive fibers and a first adhesive.

[0107] In some embodiments, the porosity of the three-dimensional skeleton 302 is 80%~90%, and the density is 1~150 mg / cm³. 3 .

[0108] In some embodiments, the aperture size distribution of the three-dimensional skeleton 302 conforms to Equation 1: (D90-D10) / D50≤0.8.

[0109] In some embodiments, the initial compression rate of the three-dimensional skeleton 302 is 50% to 90%.

[0110] In some embodiments, the area fractal dimension D of the three-dimensional skeleton 302 f It ranges from 2.2 to 2.8.

[0111] In some embodiments, the surface of the three-dimensional skeleton 302 is connected with at least one of the functional groups -COOH, -OH, and -NH2.

[0112] In some embodiments, the I of the three-dimensional skeleton 302D / I G It ranges from 1.2 to 2.0.

[0113] In some embodiments, the liquid alloy 301 comprises the following components by weight percentage: Ga: 60%~80%, In: 9%~22%, Sn: 5%~18%, Bi: 1%~5%, Zn: 0~5%.

[0114] In some embodiments, the apparent lithium diffusion coefficient of the liquid alloy 301 is 4 × 10⁻⁶. -10 m 2 / s~1×10 -7 m 2 / s.

[0115] In some embodiments, an encapsulation ring 8 is also included, which is located on the surface of the passivation layer 2 away from the current collector and is continuously distributed along the edge of the passivation layer 2 to form a closed structure.

[0116] In some embodiments, the protective film 4 further includes a second adhesive.

[0117] In some embodiments, the conductive nanofibers include at least one of single-walled carbon nanotubes, carbon nanofibers, graphene fibers, and conductive polymer fibers.

[0118] In some embodiments, the length of the conductive nanofiber is 2~100μm and the diameter is 2~200nm.

[0119] In some embodiments, the first adhesive includes at least one of polyacrylic acid, polyurethane, polyvinylidene fluoride, and polyacrylonitrile.

[0120] In some embodiments, the mass ratio of nano-conductive fibers to the first adhesive in the raw materials of the three-dimensional skeleton 302 is 6~9:1~4.

[0121] In some embodiments, in the composite active layer 3, with the porosity of the three-dimensional skeleton 302 being 100%, the filling rate of the liquid alloy 301 is 50% to 80%.

[0122] In some embodiments, in the composite active layer 3, the static contact angle between the three-dimensional skeleton 302 and the liquid alloy 301 is <30°, and the dynamic wetting time is <30s.

[0123] In some embodiments, the areal loading of the liquid alloy 301 in the negative electrode sheet is 0.1~2 mg / cm². 2 .

[0124] In some embodiments, when the surface of the three-dimensional framework 302 is connected with at least one of the functional groups -COOH and -OH, the percentage of oxygen atoms to carbon atoms on the surface of the three-dimensional framework 302 (O / C) is 0.10 to 0.35.

[0125] In some embodiments, when the surface of the three-dimensional framework 302 is connected with the functional group -NH2, the percentage of nitrogen atoms to carbon atoms (N / C) on the surface of the three-dimensional framework 302 is 0.05~0.15.

[0126] In some embodiments, the static contact angle θ between the three-dimensional skeleton 302 and the liquid alloy 301 scaffold <The static contact angle θ of the protective film 4 with the liquid alloy 301> protection <The static contact angle θ of the passivation layer 2 with the liquid alloy 301 passivation .

[0127] In some embodiments, the thickness of the encapsulation ring 8 is 40% to 60% of the thickness of the composite active layer 3, and the width is 0.005% to 0.05% of the short side length of the negative electrode current collector 1.

[0128] In some embodiments, the surface energy of the encapsulation ring 8 is ≤26mN / m.

[0129] In some embodiments, the static contact angle θ between the material of the encapsulating ring 8 and the liquid alloy 301 is... edge The range is 120° to 150°.

[0130] In some embodiments, the encapsulation ring 8 is made of at least one of polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVDF), and fluorinated ethylene propylene copolymer (FEP).

[0131] In some embodiments, the lithium diffusion material is dispersed in the protective film 4 as lithium diffusion material particles.

[0132] In some embodiments, in the protective film 4, the lithium diffusion material serves as a coating layer, coating at least a portion of the surface of the zero-dimensional carbon nanomaterial.

[0133] In some embodiments, the protective film 4 comprises, by mass percentage: 10% to 90% zero-dimensional nano-carbon material, 1% to 89% lithium diffusion material, and 1% to 30% second adhesive.

[0134] In some embodiments, the particle size D50 of the zero-dimensional carbon nanomaterial is 5~50 nm.

[0135] In some embodiments, the particle size D50 of the lithium diffusion material particles is 1~50 nm.

[0136] In some embodiments, when the lithium diffusion material is used as a coating layer to coat at least a portion of the surface of the zero-dimensional carbon nanomaterial, the thickness of the coating layer is 1~20 nm.

[0137] In some embodiments, the zero-dimensional carbon nanomaterial includes at least one of conductive carbon black, carbon quantum dots, fullerene, and carbon nano-onion.

[0138] In some embodiments, the lithium diffusion material includes at least one of metal nitrides, metal phosphides, and metal halides.

[0139] In some embodiments, the second adhesive comprises an organic polymer adhesive.

[0140] In some embodiments, the protective film 4 comprises, by weight percentage: 30% to 60% zero-dimensional nano-carbon material, 35% to 65% lithium diffusion material, and 5% to 15% second adhesive.

[0141] In some embodiments, the metals in the metal nitrides, metal phosphides, and metal halides are each independently selected from at least one of lithium, aluminum, magnesium, tin, zinc, niobium, iron, manganese, copper, indium, bismuth, antimony, and lanthanum.

[0142] In some embodiments, the organic polymer adhesive includes at least one selected from polyvinylidene fluoride, polyvinylidene fluoride-hexafluoropropylene copolymer, polyethylene oxide, polyacrylonitrile, polymethyl methacrylate, and polystyrene. In some embodiments, the surface resistivity of the passivation layer 2 is <10 Ω / sq.

[0143] In some embodiments, the texture factor of the lowest surface energy crystal plane in the passivation layer 2 is ≥1.5; in some embodiments, the texture factor of the lowest surface energy crystal plane in the passivation layer 2 is ≥2.5.

[0144] In some embodiments, the material of the negative electrode current collector 1 includes at least one of copper-based materials, iron-carbon-based materials, nickel-based materials, and titanium-based materials.

[0145] In some embodiments, the material of the passivation layer 2 includes at least one of Mo, W, Ta, TiN, and MAX phase materials.

[0146] In some embodiments, the negative electrode current collector 1 includes at least one of copper foil, stainless steel foil, nickel foil, and titanium foil.

[0147] In some embodiments, the MAX phase material includes at least one of Ti3AlC2 and Cr2AlC.

[0148] In some embodiments, the surface resistivity of the passivation layer 2 is <5Ω / sq.

[0149] Example 2 This embodiment provides a negative electrode sheet with a length of 100mm and a width of 80mm. See below for reference. Figure 1 The negative electrode sheet provided in this embodiment is described, including: The negative electrode current collector 1, the composite active layer 3 located on both sides of the negative electrode current collector 1, the protective film 4 located on the side of the composite active layer 3 away from the negative electrode current collector 1, the passivation layer 2 located between the negative electrode current collector 1 and the composite active layer 3, and the encapsulation ring 8 located on the surface of the passivation layer 2 away from the negative electrode current collector 1, the encapsulation ring 8 being continuously distributed along the edge of the passivation layer 2 to form a closed structure.

[0150] The negative electrode current collector 1 uses rolled copper foil with a thickness of 10μm, a length of 100mm, and a width of 80mm.

[0151] The passivation layer 2 is a 100nm thick TiN with a surface resistivity of 8.7Ω / sq. The lowest surface energy crystal plane of TiN is the (111) crystal plane, and its crystal texture coefficient TC(111) is 2.8.

[0152] The encapsulating ring 8 has a thickness of 13 μm and a width of 8 μm. It is made of polytetrafluoroethylene (PTFE) (surface energy 18.6 mN / m) and has a static contact angle θ with the liquid alloy 301. edge It is 135°.

[0153] The composite active layer 3 has a thickness of 31 μm and includes a three-dimensional skeleton 302 with pores, and a liquid alloy 301 filling at least part of the pores of the three-dimensional skeleton 302.

[0154] The three-dimensional framework 302 has a thickness of 31 μm and is composed of single-walled carbon nanotubes (SWCNTs, 2-5 nm in diameter and 5-15 μm in length) and polyacrylic acid (PAA) as the first binder, with a SWCNT to PAA mass ratio of 8:2. It also includes sodium dodecylbenzenesulfonate and sodium cholate as dispersants in a 1:1 mass ratio, with the amount of dispersant being 1% of the total mass of SWCNTs and PAA. In the three-dimensional framework 302, the single-walled carbon nanotubes form a textured interlock, and the PAA anchors the single-walled carbon nanotubes, jointly maintaining the structural stability of the three-dimensional framework 302. Furthermore, the surface of the three-dimensional framework 302 is also connected with catechol functional groups and amino functional groups; the O / C atomic ratio of the surface of the three-dimensional framework 302 is 0.25, and the N / C atomic ratio is 0.12. The three-dimensional framework 302 has an average pore size of 150 nm, with 85% of the pore volume in the range of 100–200 nm. Its (D90–D10) / D50 ratio is 0.65, its area fractal dimension is 2.45, its porosity is 85%, and its density is 45 mg / cm³. 3The compression rate is 78% and the rebound rate is 95%; the average compression rate at 2MPa is 62% and the average rebound rate is 98%, and the structural retention rate is 97% after 100 cycles of compression.

[0155] Liquid alloy 301 comprises, by mass percentage, 68% Ga, 18% In, 10% Sn, 2% Bi, and 2% Zn. The melting point of liquid alloy 301 is 11°C, and its viscosity at 80°C is 5.2 mPa·s. Based on a 100% porosity of the carbonaceous three-dimensional framework 302, the filling rate of liquid alloy 301 is 75%, and its surface loading is 0.8 mg / cm³. 2 The apparent diffusion coefficient is 5 × 10⁻⁶. -10 m 2 / s.

[0156] The static contact angle between the three-dimensional skeleton 302 and the liquid alloy 301 is 18°, and the dynamic wetting time is 12s.

[0157] The static contact angle θ of the protective film 4 with liquid alloy 301 protection The static contact angle θ between passivation layer 2 and liquid alloy 301 is 86°. passivation The angle is 105°. The thickness of the protective film 4 is 2 μm, and the electronic conductivity is 2.5 × 10⁻⁶. -2 S / cm, ionic conductivity 8×10 -4 S / cm, wherein, by mass percentage, comprises: 45% zero-dimensional nano-carbon material (Super C, D50 of 30nm), 45% lithium diffusion material (AlN, D50 of 20nm), and 10% second binder (polyvinylidene fluoride), wherein the lithium diffusion material is dispersed as lithium diffusion material particles in the protective film 4.

[0158] This embodiment also provides a method for preparing the above-mentioned negative electrode sheet, including the following steps: (1) The negative electrode current collector was ultrasonically cleaned with acetone, ethanol and deionized water for 15 min in sequence, then soaked in 5wt% HCl for 2 min, rinsed with deionized water and dried.

[0159] TiN passivation layers were deposited on both sides of the negative electrode current collector using magnetron sputtering with a titanium target and a base vacuum of 5 × 10⁻⁶. -4 At a substrate temperature of 330℃, an argon flow rate of 30 sccm, a nitrogen flow rate of 7.5 sccm, and a working pressure of 0.5 Pa, TiN was sputtered onto the negative electrode current collector at a sputtering power of 150 W and a deposition rate of 8 nm / min for 12.5 min.

[0160] A nickel template with an annular groove pattern on its surface is provided, the groove being 13 μm deep and 8 μm wide. A low surface energy polymer material (polytetrafluoroethylene (PTFE) dispersion) is filled into the annular groove, and excess material is scraped off. The template is aligned and adhered to the surface of the passivation layer, and a pressure of 2 MPa is applied and held for 30 seconds to transfer the material from the annular groove to the passivation layer surface. Subsequently, it is sintered and cured at 380°C for 30 minutes. The template is removed, yielding an encapsulation ring attached to the edge of the passivation layer. Measurements show that the encapsulation ring has a thickness of 13 μm and a width of 8 μm.

[0161] (2) Add SWCNT and PAA to deionized water to prepare a dispersion with a total solid content of 1 wt%, and add dispersant. Disperse the mixture at 5000 rpm for 30 min using a high-speed shear press, and then sonicate it at 800 W for 30 min using a cell disruptor to obtain a three-dimensional skeleton slurry.

[0162] The three-dimensional skeleton slurry was coated onto the surface of the current collector with a passivation layer, and the wet film thickness was 80 μm. The coated wet film was vacuum dried at -50℃ for 12 h, and then annealed at 150℃ in an argon atmosphere for 2 h to obtain the anchored three-dimensional skeleton.

[0163] The three-dimensional skeleton was immersed in a dopamine solution with a mass concentration of 5 wt% and a pH of 8.5 for 12 h, then removed and washed with deionized water, and vacuum dried at 60 °C for 12 h to introduce catechol functional groups and amino functional groups onto the surface of the three-dimensional skeleton.

[0164] (3) Weigh out the corresponding mass of high-purity metals according to the mass ratio of Ga:In:Sn:Bi:Zn as 68:18:10:2:2, melt them in an argon atmosphere at 150℃ for 2 hours to make them evenly mixed, and degas them in a vacuum for 15 minutes to obtain a liquid alloy.

[0165] At 80℃ and a vacuum degree ≤10Pa, the three-dimensional skeleton obtained in step (2) is immersed in the liquid alloy, argon gas is introduced to 0.5MPa, and it is left to stand for 30min.

[0166] (4) Zero-dimensional carbon nanomaterials (Super C, 30 nm), lithium diffusion material, and a second binder were added to the solvent N-methylpyrrolidone (NMP) to make the slurry solid content 5 wt%; the slurry was then ball-milled at 500 rpm for 2 h. A wet film with a thickness of 20 μm was coated onto the PET release film using a microgravure coating at a coating speed of 2 m / min. The wet film was dried at 60℃ for 1 h by forced air drying and then at 100℃ for 12 h by vacuum drying. Finally, a protective film was obtained by isostatic pressing at 60℃ and 500 MPa for 10 min.

[0167] Example 3 This embodiment provides a negative electrode sheet, which differs from Embodiment 2 only in that the thickness of the composite active layer is 46 μm, the thickness of the three-dimensional framework is 46 μm, the porosity is 81%, the average pore size of the three-dimensional framework is 152 nm, and 84% of the pore volume is in the range of 100~200 nm, the (D90-D10) / D50 is 0.68, the area fractal dimension is 2.38, and the density is 48 mg / cm³. 3 The initial compression rate of the three-dimensional skeleton is 72%, and the springback rate is 92%; the average compression rate is 55% and the average springback rate is 95% at 2MPa; after 100 cycles of compression, the structural retention rate is 93%.

[0168] Example 4 This embodiment provides a negative electrode sheet. Compared with Embodiment 2, the only difference is that the single-walled carbon nanotubes used have a length of 10-20 μm, an average pore size of 145 nm in the three-dimensional framework, and 85% of the pore volume is in the range of 100-200 nm. The (D90-D10) / D50 ratio is 0.72, the area fractal dimension is 2.52, the porosity is 96%, and the density is 32 mg / cm³. 3 The initial compression ratio is 82%, and the springback rate is 93%; the average compression ratio at 2 MPa is 78%, the average springback rate is 94%, and the structural retention rate after 100 cycles of compression is 92%; based on the porosity of the carbonaceous three-dimensional skeleton being 100%, the filling rate of the liquid alloy is 79%, and the surface load is 0.9 mg / cm³. 2 .

[0169] Example 5 This embodiment provides a negative electrode sheet, which differs from Embodiment 2 only in that the surface of the three-dimensional skeleton does not contain catechol or amine functional groups; the filling rate of the liquid alloy is 75%; and the static contact angle between the three-dimensional skeleton and the liquid alloy is 29°.

[0170] Example 6 This embodiment provides a negative electrode sheet. Compared with Embodiment 2, the only differences are that the thickness of the composite active layer is 21 μm, the thickness of the three-dimensional framework is 21 μm, the average pore size of the three-dimensional framework is 148 nm, and 81% of the pore volume is in the range of 100~200 nm. The (D90-D10) / D50 is 0.62, the area fractal dimension is 2.39, the porosity is 87%, and the density is 44 mg / cm³. 3 The initial compression rate was 76%, and the rebound rate was 94%; the average compression rate at 2MPa was 59%, the average rebound rate was 97%, and the structural retention rate was 96% after 100 cycles of compression.

[0171] Example 7 This embodiment provides a negative electrode sheet, which differs from Embodiment 2 only in that the liquid alloy comprises, by mass percentage, 65% Ga, 20% In, 10% Sn, and 5% Bi; a melting point of -19°C, and a viscosity of 3.1 mPa·s at 80°C; and, based on a porosity of 100% for the carbonaceous three-dimensional framework, a filling rate of 73% and an areal loading of 0.78 mg / cm³. 2 The apparent diffusion coefficient is 4.2 × 10⁻⁶. -10 m 2 / s; the static contact angle between the three-dimensional skeleton and the liquid alloy is 22°, and the dynamic wetting time is 15s.

[0172] Example 8 This embodiment provides a negative electrode sheet, which differs from Embodiment 2 only in that an equal mass of Sn3P2 (D50 of 50nm) is used instead of AlN in the protective film; the electronic conductivity of the protective film is 2.8×10⁻⁶. -2 S / cm, ionic conductivity 1.2×10 -3 S / cm. Static contact angle θ of the protective film with respect to the liquid alloy. protection It is 91°.

[0173] Example 9 This embodiment provides a negative electrode sheet, which differs from Embodiment 2 only in that the protective film has a thickness of 1 μm and an electronic conductivity of 2.5 × 10⁻⁶. -2 S / cm, ionic conductivity 8.0×10 -4 S / cm.

[0174] Example 10 This embodiment provides a negative electrode sheet. Compared with Embodiment 2, the only difference is that an equal mass of Ketjen Black KB is used instead of Super C in the protective film, and the electronic conductivity of the protective film is 5.1 × 10⁻⁶. -2 S / cm, ionic conductivity 8.9×10 - 4 S / cm. Static contact angle θ of the protective film with respect to the liquid alloy. protection It is 79°.

[0175] Example 11 This embodiment provides a negative electrode sheet, which differs from Embodiment 2 only in that the protective film has a thickness of 8 μm and an electronic conductivity of 2.2 × 10⁻⁶. -2 S / cm, ionic conductivity 6.3×10 -4 S / cm.

[0176] Example 12 This embodiment provides a negative electrode sheet, which differs from Embodiment 2 only in that the crystal texture coefficient TC(111) of TiN in the passivation layer is 1.5. The static contact angle θ of the passivation layer with the liquid alloy is... passivation It is 98°.

[0177] Example 13 This embodiment provides a negative electrode sheet with a length of 100mm and a width of 80mm, comprising: The negative electrode current collector includes a composite active layer on both sides of the negative electrode current collector, a protective film on the side of the composite active layer away from the negative electrode current collector, a passivation layer between the negative electrode current collector and the composite active layer, and an encapsulation ring on the surface of the passivation layer away from the negative electrode current collector. The encapsulation ring is continuously distributed along the edge of the passivation layer to form a closed structure.

[0178] The negative electrode current collector uses rolled copper foil with a thickness of 4μm, a length of 100mm, and a width of 80mm.

[0179] The passivation layer is a 50nm thick metallic Mo with a surface resistivity of 8.5Ω / sq. The lowest surface energy crystal plane of metallic Mo is the (110) crystal plane, and its crystal texture coefficient TC(110) is 2.6.

[0180] The encapsulating ring has a thickness of 9 μm, a width of 6 μm, and is made of polytetrafluoroethylene (surface energy 18.6 mN / m). Its static contact angle with the liquid alloy is θ. edge It is 135°.

[0181] The composite active layer has a thickness of 20 μm and includes a three-dimensional skeleton with pores, and a liquid alloy filling at least part of the pores of the three-dimensional skeleton.

[0182] The three-dimensional framework has a thickness of 20 μm and is composed of single-walled carbon nanotubes (SWCNTs, 2-5 nm in diameter and 5-15 μm in length) and polyacrylic acid (PAA) as the first binder, with a SWCNT to PAA mass ratio of 6:4. It also includes sodium dodecylbenzenesulfonate and sodium cholate as dispersants in a 1:1 mass ratio, with the dispersant amounting to 1% of the total mass of SWCNTs and PAA. Within the three-dimensional framework, the single-walled carbon nanotubes form a textured interlock, and the PAA anchors the single-walled carbon nanotubes, jointly maintaining the structural stability of the three-dimensional framework. Furthermore, the surface of the three-dimensional framework is connected with catechol and amino functional groups; the N / C atomic ratio of the three-dimensional framework surface is 0.08; and the O / C atomic ratio of the three-dimensional framework surface is 0.15. The three-dimensional framework has an average pore size of 100 nm, with 85% of the pore volume in the range of 100–200 nm. Its (D90–D10) / D50 ratio is 0.58, its area fractal dimension is 2.37, its porosity is 86%, and its density is 51 mg / cm³. 3The initial compression rate was 78%, and the rebound rate was 95%; the average compression rate at 2MPa was 62%, the average rebound rate was 98%, and the structural retention rate was 97% after 100 cycles of compression.

[0183] The liquid alloy comprises, by mass percentage, 77% Ga, 9% In, 5% Sn, 4% Bi, and 5% Zn. It has a melting point of -3°C and a viscosity of 6.8 mPa·s at 80°C. With a carbonaceous three-dimensional framework porosity of 100%, the liquid alloy has a filling rate of 72% and a surface loading of 0.75 mg / cm³. 2 The apparent diffusion coefficient is 4.8 × 10⁻⁶. -10 m 2 / s.

[0184] The static contact angle between the three-dimensional skeleton and the liquid alloy is 21°, and the dynamic wetting time is 14s.

[0185] Static contact angle θ of the protective film with the liquid alloy protection The static contact angle θ of the passivation layer to the liquid alloy is 87°. passivation It is 108°.

[0186] The protective film has a thickness of 1 μm and an electronic conductivity of 2.3 × 10⁻⁶. -2 S / cm, ionic conductivity 7.5×10 -4 S / cm, wherein, by mass percentage, comprises: 52% zero-dimensional nano-carbon material (Super C, D50 of 5nm), 35% lithium diffusion material (AlN, D50 of 50nm), and 13% second binder (polyvinylidene fluoride), wherein the lithium diffusion material is dispersed in the protective film as lithium diffusion material particles.

[0187] This embodiment also provides a method for preparing the above-mentioned negative electrode sheet, including the following steps: (1) The negative electrode current collector was ultrasonically cleaned with acetone, ethanol and deionized water for 15 min in sequence, then soaked in 5wt% HCl for 2 min, rinsed with deionized water and dried.

[0188] A passivation layer of metallic Mo was deposited on both sides of the negative electrode current collector using magnetron sputtering. A molybdenum target was used, and the background vacuum was 5 × 10⁻⁶. -4 At a substrate temperature of 330℃, an argon flow rate of 30 sccm, and a working pressure of 0.5 Pa, metallic Mo was sputtered onto the negative electrode current collector at a sputtering power of 150 W and a deposition rate of 8 nm / min for a deposition time of 6.25 min.

[0189] A nickel template with an annular groove pattern on its surface is provided, the groove being 9 μm deep and 6 μm wide. A low surface energy polymer material (polyvinylidene fluoride (PTFE) dispersion) is filled into the annular groove, and excess material is scraped off. The template is aligned and adhered to the surface of the passivation layer, and a pressure of 2 MPa is applied and held for 30 seconds to transfer the material from the annular groove to the passivation layer surface. Subsequently, it is sintered and cured at 380°C for 30 minutes. The template is then removed, yielding an encapsulation ring attached to the edge of the passivation layer. Measurements show that the encapsulation ring has a thickness of 9 μm and a width of 6 μm.

[0190] (2) Add SWCNT and PAA to deionized water to prepare a dispersion with a total solid content of 1 wt%, and add dispersant. Disperse the mixture at 5000 rpm for 30 min using a high-speed shear press, and then sonicate it at 800 W for 30 min using a cell disruptor to obtain a three-dimensional skeleton slurry.

[0191] The three-dimensional skeleton slurry was coated onto the surface of the current collector with a passivation layer, and the wet film thickness was 55 μm. The coated wet film was vacuum dried at -50℃ for 12 h, and then annealed at 150℃ in an argon atmosphere for 2 h to obtain the anchored three-dimensional skeleton.

[0192] The three-dimensional skeleton was immersed in a dopamine solution with a mass concentration of 5 wt% and a pH of 8.5 for 12 h, then removed and washed with deionized water, and vacuum dried at 150 °C for 12 h to introduce catechol functional groups and amino functional groups onto the surface of the three-dimensional skeleton.

[0193] (3) Weigh out the corresponding mass of high-purity metals according to the mass ratio of Ga:In:Sn:Bi:Zn as 77:9:5:4:5, melt them in an argon atmosphere at 150℃ for 2 hours to make them evenly mixed, and degas them in a vacuum for 15 minutes to obtain a liquid alloy.

[0194] At 80℃ and a vacuum degree ≤10Pa, the three-dimensional skeleton obtained in step (2) is immersed in the liquid alloy, argon gas is introduced to 0.5MPa, and it is left to stand for 30min.

[0195] (4) Zero-dimensional carbon nanomaterials, lithium diffusion materials, and a second binder were added to the solvent N-methylpyrrolidone (NMP) to make the slurry solid content 5wt%; the slurry was then ball-milled at 500 rpm for 2 h. A wet film with a thickness of 20 μm was then coated onto the PET release film using a microgravure coating at a coating speed of 2 m / min. The wet film was dried at 60℃ for 1 h by forced air drying and then at 100℃ for 12 h by vacuum drying. Finally, a protective film was obtained by isostatic pressing at 60℃ and 500 MPa for 10 min.

[0196] Example 14 This embodiment provides a negative electrode sheet with a length of 100mm and a width of 80mm, comprising: The negative electrode current collector includes a composite active layer on both sides of the negative electrode current collector, a protective film on the side of the composite active layer away from the negative electrode current collector, a passivation layer between the negative electrode current collector and the composite active layer, and an encapsulation ring on the surface of the passivation layer away from the negative electrode current collector. The encapsulation ring is continuously distributed along the edge of the passivation layer to form a closed structure.

[0197] The negative electrode current collector uses rolled copper foil with a thickness of 9μm, a length of 100mm, and a width of 80mm.

[0198] The passivation layer is a 200nm thick metal Ta with a surface resistivity of 4.9Ω / sq. The lowest surface energy crystal plane of the metal Ta is the (110) crystal plane, and its crystal texture coefficient TC(110) is 3.8.

[0199] The encapsulating ring has a thickness of 25 μm and a width of 40 μm. It is made of polyvinylidene fluoride (surface energy 25 mN / m) and has a static contact angle θ with the liquid alloy. edge It is 124°.

[0200] The composite active layer has a thickness of 45 μm and includes a three-dimensional skeleton with pores, and a liquid alloy filling at least part of the pores of the three-dimensional skeleton.

[0201] The three-dimensional framework has a thickness of 45 μm and its raw materials include carbon nanofibers (CNF, diameter 150~200 nm, length 80~100 μm), and polyacrylic acid (PAA) as the first binder, with a CNF to PAA mass ratio of 9:1. It also includes sodium dodecylbenzenesulfonate and sodium cholate as dispersants in a 1:1 mass ratio, with the amount of dispersant being 0.5% of the total mass of CNTs and PAA. Within the three-dimensional framework, the carbon nanofibers form a texture interlock, and the PAA anchors the carbon nanofibers, jointly maintaining the structural stability of the three-dimensional framework. Furthermore, the I... D / I G The density is 1.9. The average pore size of the three-dimensional framework is 196 nm, and 81% of the pore volume is in the range of 100-200 nm. The (D90-D10) / D50 ratio is 0.72, the area fractal dimension is 2.55, the porosity is 85%, and the density is 42 mg / cm³. 3 The initial compression rate was 63%, and the rebound rate was 81%; the average compression rate at 2MPa was 52%, the average rebound rate was 97%, and the structural retention rate was 95% after 100 cycles of compression.

[0202] The liquid alloy comprises, by mass percentage, 60% Ga, 22% In, 16% Sn, 1% Bi, and 1% Zn. It has a melting point of -8°C and a viscosity of 7.5 mPa·s at 80°C. With a carbonaceous three-dimensional framework porosity of 100%, the liquid alloy has a filling rate of 74% and a surface loading of 0.82 mg / cm³. 2 The apparent diffusion coefficient is 4.5 × 10⁻⁶. -10 m 2 / s.

[0203] The static contact angle between the three-dimensional skeleton and the liquid alloy is 28°, and the dynamic wetting time is 27s.

[0204] Static contact angle θ of the protective film with the liquid alloy protection The static contact angle θ of the passivation layer to the liquid alloy is 83°. passivation It is 112°.

[0205] The protective film has a thickness of 5 μm and an electronic conductivity of 2.2 × 10⁻⁶. -2 S / cm, ionic conductivity 6.9×10 -4 S / cm, wherein, by mass percentage, comprises: 40% zero-dimensional carbon nanomaterial (Super C, D50 of 50 nm), 55% lithium diffusion material (AlN), and 5% second binder (polyvinylidene fluoride); the lithium diffusion material serves as a coating layer, coating at least a portion of the surface of the zero-dimensional carbon nanomaterial, and the thickness of the coating layer is 8 nm (thickness measured by TEM).

[0206] This embodiment also provides a method for preparing the above-mentioned negative electrode sheet, including the following steps: (1) The negative electrode current collector was ultrasonically cleaned with acetone, ethanol and deionized water for 15 min in sequence, then soaked in 5wt% HCl for 2 min, rinsed with deionized water and dried.

[0207] A metal Ta passivation layer was deposited on both sides of the negative electrode current collector using magnetron sputtering. A tantalum target was used, and the background vacuum was 5 × 10⁻⁶. -4 At a substrate temperature of 330℃, an argon flow rate of 30 sccm, and a working pressure of 0.5 Pa, metallic Ta was sputtered onto the negative electrode current collector at a sputtering power of 150 W and a deposition rate of 8 nm / min for 25 min.

[0208] A nickel template with an annular groove pattern on its surface is provided, the groove being 25 μm deep and 40 μm wide. A low surface energy polymer material (polyvinylidene fluoride (PTFE) dispersion) is filled into the annular groove, and excess material is scraped off. The template is aligned and adhered to the surface of the passivation layer, and a pressure of 2 MPa is applied and held for 30 seconds to transfer the material from the annular groove to the passivation layer surface. Subsequently, it is sintered and cured at 200°C for 30 minutes. The template is then removed, yielding an encapsulation ring attached to the edge of the passivation layer. Measurements show that the encapsulation ring has a thickness of 25 μm and a width of 40 μm.

[0209] (2) Add SWCNT and PAA to deionized water to prepare a dispersion with a total solid content of 1 wt%, and add dispersant. Disperse the mixture at 5000 rpm for 30 min using a high-speed shear press, and then sonicate it at 800 W for 30 min using a cell disruptor to obtain a three-dimensional skeleton slurry.

[0210] The three-dimensional skeleton slurry was coated onto the surface of the current collector with a passivation layer, and the wet film thickness was 115 μm. The coated wet film was vacuum dried at -50℃ for 12 h, and then annealed at 150℃ in an argon atmosphere for 2 h to obtain the anchored three-dimensional skeleton.

[0211] The three-dimensional skeleton was placed in a plasma processing chamber, and argon was used as the working gas to etch the surface of the three-dimensional skeleton. The parameters were: radio frequency power 150W and processing time 10min.

[0212] (3) Weigh out the corresponding mass of high-purity metals according to the mass ratio of Ga:In:Sn:Bi:Zn as 68:18:10:2:2, melt them in an argon atmosphere at 150℃ for 2 hours to make them evenly mixed, and degas them in a vacuum for 15 minutes to obtain a liquid alloy.

[0213] At 80℃ and a vacuum degree ≤10Pa, the three-dimensional skeleton obtained in step (2) is immersed in the liquid alloy, argon gas is introduced to 0.5MPa, and it is left to stand for 30min.

[0214] (4) Zero-dimensional carbon nanomaterials (Super C, D50 of 50 nm) were placed in an atomic layer deposition reactor. Trimethylaluminum was used as the aluminum precursor and ammonia was used as the nitrogen source. ALD (atomic layer deposition) cycles were performed at 300 °C to coat the surface of Super C with a nano-AlN layer with a coating thickness of 8 nm, resulting in core-shell composite particles of zero-dimensional carbon nanomaterials@lithium diffusion material (Super C@AlN). Super C@AlN and a second binder were added to N-methylpyrrolidone to make the slurry solid content 5 wt%, and the slurry was ball-milled at 500 rpm for 2 h. A wet film with a thickness of 20 μm was coated on a PET release film by microgravure at a coating speed of 2 m / min. The wet film was dried at 60 °C for 1 h by forced air drying and at 100 °C for 12 h by vacuum drying. Finally, a protective film was obtained by isostatic pressing at 60 °C and 500 MPa for 10 min.

[0215] Example 15 This embodiment provides a negative electrode sheet, which differs from Embodiment 2 only in that it does not have an encapsulation ring.

[0216] Comparative Example 1 This comparative example provides a negative electrode sheet, which differs from Example 2 only in that a rolled copper foil with a thickness of 10 μm is directly used as the negative electrode sheet.

[0217] Comparative Example 2 This comparative example provides a negative electrode sheet, which differs from Example 2 only in that it does not have a passivation layer.

[0218] Comparative Example 3 This comparative example provides a negative electrode sheet, which differs from Example 2 only in that the composite active layer does not have a three-dimensional framework.

[0219] Comparative Example 4 This comparative example provides a negative electrode sheet, which differs from Example 2 only in that the composite active layer uses particles with a particle size of 1-2 μm and a specific surface area of ​​800 m². 2 / g porous carbon substitute three-dimensional framework.

[0220] Comparative Example 5 This comparative example provides a negative electrode sheet, which differs from Example 2 only in that the composite active layer does not contain liquid alloy.

[0221] Comparative Example 6 This comparative example provides a negative electrode sheet, which differs from Example 2 only in that the liquid alloy in the composite active layer comprises, by mass percentage, 80% Ga and 20% In, and the melting point of the liquid alloy is 50°C. Assuming the porosity of the carbonaceous three-dimensional framework is 100%, the filling rate of the liquid alloy is 31%.

[0222] Comparative Example 7 This comparative example provides a negative electrode sheet, which differs from Example 2 only in that it does not have a protective film.

[0223] Comparative Example 8 This comparative example provides a negative electrode sheet, which differs from Example 2 only in that the protective film comprises: 90% zero-dimensional nano-carbon material (Super C, 30nm), 10% second binder (polyvinylidene fluoride), and the static contact angle θ of the protective film with the liquid alloy is... protection It is 73°.

[0224] Comparative Example 9 This comparative example provides a negative electrode sheet, which differs from Example 2 only in that the protective film comprises: 90% lithium diffusion material (AlN, D50 of 20nm), 10% second binder (polyvinylidene fluoride), and the static contact angle θ of the protective film with the liquid alloy. protection It is 108°.

[0225] Comparative Example 10 This comparative example provides a negative electrode sheet, which differs from Example 2 only in that carbon cloth (with inter-fiber pore size of 5~10μm) is used instead of a three-dimensional skeleton in the composite active layer.

[0226] Comparative Example 11 This comparative example provides a negative electrode sheet, which differs from Example 2 only in that the average pore size of the three-dimensional skeleton in the composite active layer is 378 nm.

[0227] Comparative Example 12 This comparative example provides a negative electrode sheet, which differs from Example 2 only in that the initial density of the protective film is only 80%.

[0228] Experimental Example 1 Preparation of positive electrode sheet: LiNi positive electrode active material was taken in a mass ratio of 86:12:1:1. 0.8 Co 0.1 Mn 0.1 O2, solid electrolyte particles Li3InCl6, conductive carbon black (SP) as a conductive agent, and styrene-butadiene-styrene block copolymer (SEBS) as a binder are mixed and xylene is added as a solvent to obtain a positive electrode slurry with a solid content of 52 wt%. The positive electrode slurry is coated onto a current collector aluminum foil (12 μm thick, 90 mm × 70 mm in size) and dried to obtain a positive electrode sheet with a coating areal density of 24 mg / cm³. 2 .

[0229] The solid electrolyte membrane uses lithium lanthanum zirconium oxide (LLZO) solid electrolyte membrane with a thickness of 25 μm and a size of 110 mm × 90 mm; the mass percentage of LLZO is 95%.

[0230] The negative electrode sheet used is the negative electrode sheet prepared in the examples and comparative examples.

[0231] A solid electrolyte membrane, a negative electrode, another solid electrolyte membrane, and a positive electrode are sequentially stacked, for a total of 5 negative electrode sheets and 4 positive electrode sheets. The composite is then pressurized at 50 MPa and 60 °C for 20 min and encapsulated to obtain an all-solid-state soft-pack battery.

[0232] A schematic diagram of the fabricated all-solid-state pouch cell structure is shown in the image. Figure 2 A solid electrolyte membrane 5, a positive electrode active layer 6, and a positive electrode current collector 7 are sequentially disposed on the side of the protective membrane 4 away from the composite active layer 3.

[0233] The negative electrode sheet and its corresponding all-solid-state pouch cell were tested, and the data obtained are shown in Tables 1 and 2.

[0234] (1) Corrosion depth: The current collector with passivation layer was immersed in the liquid alloy used in the corresponding examples and comparative examples at 80°C for 1000h, and the cross section was observed by transmission electron microscopy (TEM) to measure the thickness of corrosion.

[0235] (2) Density of the protective film: Weigh the protective film using a precision balance (accurate to 0.01 mg), take 1 cm × 1 cm unit samples at 5 different locations, measure their thickness with a micrometer, and calculate the apparent density. The true density of the protective film is determined using a true density tester (helium displacement method). Density = Apparent density / True density × 100%.

[0236] The all-solid-state pouch cell was charged at a constant current of 0.1C to the cutoff voltage (4.25V), and then charged at a constant voltage to 0.05C. The cell was then disassembled in an inert atmosphere glove box, the protective film was removed, and the density was measured and calculated again using the method described above.

[0237] (3) Alloy grain parameters: After assembling the negative electrode into an all-solid-state battery, the charging and discharging current density is 0.1C. After charging and discharging to the required state of charge (20%SOC, 50%SOC, 100%SOC), the negative electrode is disassembled in an inert atmosphere glove box and the negative electrode is removed. Electron backscatter diffraction (EBSD) is used to analyze the cross-section of the negative electrode, at least 200 alloy grains are counted, the alloy grain size is measured, and the average alloy grain size D (nm) and the standard deviation of alloy grain size distribution σ (nm) are calculated.

[0238] Based on EBSD images, the average distance between adjacent alloy grains, i.e., the average alloy grain spacing λ (nm), was measured using image processing software (ImageJ), and the shortest distance between alloy grain boundaries was taken. High-resolution transmission electron microscopy (HRTEM) was used to capture high-resolution images of the alloy grain boundary region, and the width of the disorder layer of the alloy grain boundary, i.e., the alloy grain boundary width d (nm), was measured. The average value was taken from at least 10 different alloy grain boundary locations.

[0239] Based on EBSD analysis data, the number of alloy grains N (grains / μm) per unit volume was counted. 3 At least 10 different regions' fields of view were statistically analyzed, and the average value was taken.

[0240] Based on the data obtained from the above tests, calculate ψ=D 3 / (λ·d·N 2 / 3 The ψ values ​​were tested at three different depths of discharge (20% SOC, 50% SOC, and 100% SOC), and the average value was taken as the ψ value.

[0241] Based on the average aperture value D of the three-dimensional skeleton pore Calculate D based on the average alloy grain size D obtained above. pore The value of / D.

[0242] (4) Elastic modulus test: After the solid-state battery is fully charged, it is disassembled and the elastic modulus of the passivation layer, composite active layer and protective film after full charge is tested using a nanoindenter. The unit is MPa. The elastic modulus of the composite active layer is E. active The elastic modulus of the protective film is E protection The elastic modulus of the passivation layer is E passivation .

[0243] (5) Volume matching formula: Calculate V respectively expansion × (1-R initial ), P scaffold The value of ×0.7, where V expansion R is the volume expansion rate of the liquid alloy after it is fully filled. initial P is the initial compression ratio of the 3D skeleton. scaffold The porosity of the three-dimensional skeleton; the test method for the volume expansion rate of the liquid alloy after full charging is as follows: construct an all-solid-state mold battery with a diameter of 10mm, the negative electrode contains only liquid alloy, the separator is an LLZO ceramic sheet, the counter electrode is a lithium sheet, after full charging, disassemble, measure the volume of the liquid alloy before and after full charging, and further calculate the volume expansion rate.

[0244] Table 1

[0245] Table 2

[0246] As can be seen from Tables 1 and 2, the negative electrode sheets provided in the embodiments of this application all have a certain degree of corrosion resistance due to the presence of the passivation layer. In Example 12, the corrosion effect is worse compared with other examples because the minimum surface energy crystal texture coefficient of the passivation layer is low. In Comparative Example 1, rolled copper foil is used directly as the negative electrode sheet, and in Comparative Example 2, there is no passivation layer, and the current collector is directly corroded with visible holes. The negative electrode sheets provided in the embodiments of this application have high initial density and high density after charging due to the reasonable ratio of protective film raw materials. In contrast, Comparative Example 7 does not have a protective film, Comparative Example 8 does not have lithium diffusion material added to the protective film, Comparative Example 9 does not have zero-dimensional nano-carbon material added to the protective film, and in Comparative Example 12, the initial density of the protective film is only 80%. All of these result in poor density of the protective film after the first charge, which fails to achieve a suitable protective effect. Furthermore, in the embodiments provided in this application, due to the reasonable combination of three-dimensional skeleton performance and liquid alloy, the average alloy grain size after charging is within a reasonable range, and the ψ value is reasonable, satisfying the requirement that Coble creep plays a major diffusion role in solid-state batteries. In the embodiments provided in this application, the solid-state batteries made using the corresponding negative electrode sheets satisfy 1.25≤D pore / D≤2.5, V expansion ×(1-R initial )≤P scaffold ×0.7, E active <E protection <E passivation It can reduce the decline in Coble creep efficiency and prevent the overflow of liquid alloy and stress concentration at the interface.

[0247] Experimental Example 2 The same all-solid-state pouch cell as in Experiment Example 1 was used to test its electrical performance, and the results are shown in Table 3.

[0248] (1) Initial Coulombic Efficiency Test: The test pressure for the pouch cell was 1 MPa, and the temperature was 30℃. The cell was charged at a constant current of 0.1C to 4.25V, then switched to constant voltage charging to 0.05C and stopped. The first charge capacity was recorded as C0. Then, the cell was discharged at 0.1C to the cutoff voltage of 2.5V and stopped. The first discharge capacity was recorded as C1. Initial Coulombic Efficiency = C1 / C0 × 100%.

[0249] (2) Cyclic performance test: After 3 charge-discharge cycles at a charge-discharge current density of 0.1C and a charge-discharge cutoff voltage of 2.5~4.25V, a 0.33C / 0.33C cycle performance test was performed. Specifically: charge at 0.33C until the cutoff voltage of 4.25V and stop, and record it as the first cycle charge capacity; then discharge at 0.33C until the cutoff voltage of 2.5V and stop, and record it as the first cycle discharge capacity. Cycle for 200 cycles, and record the discharge capacity of the 200th cycle. The 200-cycle capacity retention rate = discharge capacity of the 200th cycle / discharge capacity of the 1st cycle × 100%.

[0250] The cycle performance images of the all-solid-state pouch cells corresponding to Example 2 and Comparative Example 6 are shown below. Figure 3 .

[0251] (3) Internal resistance test: According to the cycle performance test method in (2), after the soft pack battery completes the first charge and discharge cycle, it is charged to 50% SOC at 0.1C. The internal resistance is tested using an AC internal resistance tester at a test frequency of 1kHz. The data result is the impedance of the first cycle.

[0252] After 200 cycles, the impedance was determined by the cycle performance test method in (2). After the soft pack battery was charged and discharged 200 times, it was charged to 50% SOC at 0.1C. The internal resistance was tested using an AC internal resistance tester at a frequency of 1kHz. The data result was the impedance after 200 cycles.

[0253] (4) Energy density test method: The energy density of the pouch battery is calculated based on the first discharge capacity C1 obtained from the first coulombic efficiency test in (1). Energy density = C1 × average voltage / battery weight. Among them, the average voltage is the average voltage during the discharge capacity process in the first coulombic efficiency test, and the battery weight is measured by analytical balance.

[0254] Table 3

[0255] As shown in Table 3, the negative electrode sheet provided in the embodiments meets the structure specified in this application, and its energy density, cycle capacity retention, first-cycle impedance, and post-cycle impedance are all excellent. In contrast, the negative electrode sheet provided in the comparative examples does not meet the structure specified in this application, its energy density is significantly reduced, and it may experience short circuits, capacity drops, or low capacity retention during cycling. The negative electrode sheet provided by this invention can comprehensively improve the energy density, cycle performance, and safety of the corresponding solid-state battery.

[0256] Experimental Example 3 Take the corresponding negative electrode sheets from Examples 2 and 15, and prepare all-solid-state pouch cells using the same method as in Experiment 1. Test their short-circuit rates under long-cycle and high-temperature cycles, and the data obtained are shown in Table 4.

[0257] Long-term cycling: 50 all-solid-state pouch batteries from Examples 2 and 15 were tested. The specific test method was as follows: at room temperature, with a charge / discharge current density of 0.1C and a charge / discharge cutoff voltage of 2.5~4.25V, after 3 charge / discharge cycles, a 0.33C / 0.33C cycle performance test was performed; the batteries were charged at 0.33C until the cutoff voltage of 4.25V and then discharged at 0.33C until the cutoff voltage of 2.5V, for a total of 500 cycles. The number of short-circuited batteries was recorded as N1, and the short-circuit rate under long-term cycling was N1 / 50×100%.

[0258] High-temperature cycling: 50 all-solid-state pouch batteries from Examples 2 and 15 were tested. The specific test method was as follows: at 45°C, with a charge / discharge current density of 0.1C and a charge / discharge cutoff voltage of 2.5~4.25V, after 3 charge / discharge cycles, a 0.33C / 0.33C cycle performance test was performed; the batteries were charged at 0.33C until the cutoff voltage of 4.25V and then discharged at 0.33C until the cutoff voltage of 2.5V, for a total of 200 cycles. The number of short-circuited batteries was recorded as N2, and the short-circuit rate under high-temperature cycling was N2 / 50×100%.

[0259] Table 4

[0260] As can be seen from Table 4, Example 2 with the encapsulation ring has a lower short-circuit rate under both long-cycle and high-temperature cycling conditions than Example 15 without the encapsulation ring; the presence of the encapsulation ring can effectively prevent short circuits caused by the overflow of liquid alloy during cycling.

[0261] The above embodiments are merely preferred embodiments provided to fully illustrate the present invention, and the scope of protection of the present invention is not limited thereto. Equivalent substitutions or modifications made by those skilled in the art based on the present invention are all within the scope of protection of the present invention.

Claims

1. A negative electrode sheet, characterized in that, It includes a negative electrode current collector, a composite active layer located on at least one side of the negative electrode current collector, a protective film located on the side of the composite active layer away from the negative electrode current collector, and a passivation layer located between the negative electrode current collector and the composite active layer. The composite active layer includes a three-dimensional skeleton with pores, and a liquid alloy filling at least a portion of the pores of the three-dimensional skeleton; The three-dimensional skeleton has a resilience of ≥80% and an average pore size of 100~200nm; The melting point of the liquid alloy is ≤25℃; The protective film comprises zero-dimensional nano-carbon materials and lithium diffusion materials; The initial density of the protective film is ≥85%.

2. The negative electrode sheet according to claim 1, characterized in that, The thickness of the negative electrode sheet is 25~60μm; And / or, the thickness of the negative electrode current collector is 4~12μm; And / or, the thickness of the passivation layer is 50~200nm; And / or, the thickness of the composite active layer is 20~50μm; And / or, the thickness of the protective film is 1~8μm.

3. The negative electrode sheet according to claim 1 or 2, characterized in that, The negative electrode sheet satisfies at least one of the following conditions: (1) The raw materials of the three-dimensional skeleton include nano-conductive fibers and a first adhesive; (2) The porosity of the three-dimensional skeleton is 80%~90%, and the density is 1~150 mg / cm³. 3 ; (3) The aperture size distribution of the three-dimensional skeleton conforms to Equation 1: (D90-D10) / D50≤0.8; (4) The initial compression rate of the three-dimensional skeleton is 50%~90%; (5) The area fractal dimension D of the three-dimensional skeleton f The value is 2.2~2.8; (6) The surface of the three-dimensional framework is connected with at least one of the functional groups -COOH, -OH, and -NH2, and / or, the I of the three-dimensional framework D / I G The value is 1.2~2.0; (7) The liquid alloy comprises the following components by weight percentage: Ga: 60%~80%, In: 9%~22%, Sn: 5%~18%, Bi: 1%~5%, Zn: 0~5%; (8) The apparent lithium diffusion coefficient of the liquid alloy is 4 × 10⁻⁶. -10 m 2 / s~1×10 -7 m 2 / s; (9) It also includes an encapsulation ring, which is located on the surface of the passivation layer away from the negative electrode current collector; it is continuously distributed along the edge of the passivation layer to form a closed structure; (10) The protective film also includes a second adhesive.

4. The negative electrode sheet according to claim 3, characterized in that, The conductive nanofibers include at least one of single-walled carbon nanotubes, carbon nanofibers, graphene fibers, and conductive polymer fibers. And / or, the length of the nano-conductive fiber is 2~100μm and the diameter is 2~200nm; And / or, the first adhesive comprises at least one of polyacrylic acid, polyurethane, polyvinylidene fluoride, and polyacrylonitrile; And / or, in the raw materials of the three-dimensional skeleton, the mass ratio of nano-conductive fibers to the first adhesive is 6~9:1~4; And / or, when the surface of the three-dimensional framework is connected with at least one of the functional groups -COOH and -OH, the molar ratio of oxygen atoms to carbon atoms on the surface of the three-dimensional framework is O / C of 0.10 to 0.35; And / or, when the surface of the three-dimensional framework is connected with the functional group -NH2, the molar ratio of nitrogen atoms to carbon atoms on the surface of the three-dimensional framework is N / C of 0.05~0.15; And / or, the static contact angle θ of the three-dimensional skeleton with respect to the liquid alloy. scaffold <The static contact angle θ of the protective film with the liquid alloy> protection <The static contact angle θ of the passivation layer with respect to the liquid alloy> passivation .

5. The negative electrode sheet according to claim 3, characterized in that, In the composite active layer, with the porosity of the three-dimensional skeleton being 100%, the filling rate of the liquid alloy is 50%~80%. And / or, in the composite active layer, the static contact angle θ between the three-dimensional framework and the liquid alloy scaffold <30°, dynamic wetting time t<30s; And / or, in the negative electrode sheet, the areal loading of the liquid alloy is 0.1~2 mg / cm³. 2 ; And / or, the thickness of the encapsulation ring is 40% to 60% of the thickness of the composite active layer, and the width is 0.005% to 0.05% of the short side length of the negative electrode current collector; And / or, the surface energy of the encapsulating ring material is ≤26mN / m; And / or, the static contact angle θ between the material of the encapsulating ring and the liquid alloy. edge The range is 120° to 150°.

6. The negative electrode sheet according to claim 5, characterized in that, The encapsulating ring is made of at least one of polytetrafluoroethylene, polyvinylidene fluoride, and fluorinated ethylene propylene copolymer.

7. The negative electrode sheet according to claim 3, characterized in that, The protective film comprises, by mass percentage: 10%~90% zero-dimensional nano-carbon material, 1%~89% lithium diffusion material, and 1%~30% second adhesive; And / or, the particle size D50 of the zero-dimensional carbon nanomaterial is 5~50 nm; And / or, the particle size D50 of the lithium diffusion material particles is 1~50nm; And / or, the zero-dimensional carbon nanomaterial includes at least one of conductive carbon black, carbon quantum dots, fullerene, and carbon nano-onion; And / or, the lithium diffusion material includes at least one of metal nitrides, metal phosphides, and metal halides; And / or, the second adhesive comprises an organic polymer adhesive.

8. The negative electrode sheet according to claim 7, characterized in that, The protective film comprises, by mass percentage: 30%~60% zero-dimensional nano-carbon material, 35%~65% lithium diffusion material, and 5%~15% second adhesive; And / or, the metals in the metal nitrides, metal phosphides, and metal halides are each independently selected from at least one of lithium, aluminum, magnesium, tin, zinc, niobium, iron, manganese, copper, indium, bismuth, antimony, and lanthanum; And / or, the organic polymer adhesive includes at least one of polyvinylidene fluoride, polyvinylidene fluoride-hexafluoropropylene copolymer, polyethylene oxide, polyacrylonitrile, polymethyl methacrylate, and polystyrene.

9. The negative electrode sheet according to claim 1 or 2, characterized in that, The surface resistivity of the passivation layer is <10Ω / sq; And / or, in the passivation layer, the texture factor of the lowest surface energy crystal plane is 1.5 to 4.

0.

10. The negative electrode sheet according to claim 1 or 2, characterized in that, The material of the negative electrode current collector includes at least one of copper-based materials, iron-carbon-based materials, nickel-based materials, and titanium-based materials; And / or, the material of the passivation layer includes at least one of Mo, W, Ta, TiN, and MAX phase materials.

11. The negative electrode sheet according to claim 10, characterized in that, The negative electrode current collector includes at least one of copper foil, stainless steel foil, nickel foil, and titanium foil; And / or, the MAX phase material includes at least one of Ti3AlC2 and Cr2AlC.

12. A solid-state battery, characterized in that, It includes the negative electrode sheet as described in any one of claims 1 to 11, and also includes the positive electrode sheet and a solid electrolyte membrane.

13. The solid-state battery according to claim 12, characterized in that, The ratio of the long side length of the solid electrolyte membrane and the negative electrode sheet is 1.05~1.5:1, and the ratio of the short side length is 1.05~1.5:

1. And / or, the ratio of the length of the long side of the negative electrode and the positive electrode is 1.05~1.5:1, and the ratio of the length of the short side is 1.05~1.5:1; And / or, during the charging and discharging process of the solid-state battery, when charged to above 20% SOC, the liquid alloy solidifies and transforms into alloy grains; when discharged to below 20% SOC, the alloy grains liquefy and transform into liquid alloy. The alloy grains conform to equation 2: ψ=D 3 / (λ·d·N 2 / 3 ), 1.5≤ψ≤2.0; In Equation 2, ψ is a characteristic parameter of Kober creep; D is the numerical value of the average alloy grain size, and the unit of the average alloy grain size is nm; λ is the value of the average alloy grain spacing, and the unit of the average alloy grain spacing is nm; d is the numerical value of the alloy grain boundary width, and the unit of the alloy grain boundary width is nm; N is the numerical value of the number of alloy grains per unit volume, and the unit of the number of alloy grains per unit volume is grains / μm. 3 .

14. The solid-state battery according to claim 13, characterized in that, When the solid-state battery is first charged to more than 20% SOC, the average alloy grain size is ≤80nm and the standard deviation of the alloy grain size distribution is ≤15nm. And / or, the initial density of the protective film is D1, and the density of the protective film after the first charge of the solid-state battery is D2, where D2 ≥ 92% and D2 - D1 ≥ 5%; And / or, the solid-state battery satisfies relation 3: 1.25 ≤ D pore / D≤2.5; where D pore The average aperture value of the three-dimensional skeleton is given in nm. And / or, the solid-state battery satisfies relation 4: V expansion × (1-R initial )≤P scaffold ×0.7; where V expansion R is the volume expansion rate of the liquid alloy after it is fully filled. initial P is the initial compression ratio of the 3D skeleton. scaffold Porosity of the three-dimensional framework; And / or, the fully charged solid-state battery satisfies: the elastic modulus E of the composite active layer after full charge. active The elastic modulus E of the protective film after it is fully filled protection The elastic modulus E after the passivation layer is fully filled passivation .

15. An electrical appliance, characterized in that, Includes a solid-state battery as described in any one of claims 12 to 14, wherein the solid-state battery serves as a power supply for the electrical device.

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