An anode-free all-solid-state battery and application thereof

Abstract

This invention proposes a negative electrode-free all-solid-state battery and its application. The battery includes a positive electrode; a negative electrode current collector, including a current collector substrate and a modification layer, the modification layer including a high-entropy sulfide electrolyte; and a solid electrolyte layer, including a high-entropy sulfide electrolyte Li. 4±x‑y A y (M1 a M2 b M3 c) S 4‑δ X δ The following parameters are defined: 0 ≤ x ≤ 1.5, 0 ≤ y ≤ 1.5, and y ≤ 4 ± x; 0.4 ≤ a ≤ 0.8, 0.1 ≤ b ≤ 0.4, 0.1 ≤ c ≤ 0.3, a + b + c = 1, 0 ≤ δ ≤ 1; A is selected from one or two of Na or K; M1 is selected from one or more of Ge, Sn, Si, P, As, or B; M2 is selected from one or more of Sb, Nb, Ta, V, Mo, W, Ti, Zr, Hf, or Re; M3 is selected from one or more of Al, Ga, In, Bi, Pb, Mg, Ca, Zn, Cd, Y, Sc, La, Ba, Sr, Ce, or Sm; X is selected from one or more of O, Se, or Te. This invention enables uniform nucleation and reversible deposition of lithium ions, improving the performance of electrodeless all-solid-state batteries.

Description

Technical Field

[0001] This invention relates to the field of power battery technology, specifically to a negative electrode-free all-solid-state battery and its applications. Background Technology

[0002] Currently, anode-free solid-state lithium batteries (AFSSLBs) are considered an important development direction for next-generation high-energy batteries due to their high theoretical energy density and good safety. However, during the first charge of an AFSSLB, lithium ions need to be directly deposited on the surface of the current collector to form a metallic lithium anode. Poor contact and high interfacial impedance between the solid electrolyte and the current collector, along with uneven lithium deposition, easily lead to lithium dendrite growth and "dead lithium" phenomena, resulting in short cycle life and low coulombic efficiency. Current collector surface modification strategies are employed to improve interfacial contact, or three-dimensional porous structures are used to guide uniform lithium deposition. However, problems still exist, such as poor wettability between the current collector and the solid electrolyte, and the difficulty in simultaneously achieving ion / electron conduction, interfacial stability, and mechanical buffering. Summary of the Invention

[0003] This invention proposes a negative electrode-free all-solid-state battery and its application. The negative electrode-free all-solid-state battery and its application provided by this invention can improve the affinity of the negative electrode current collector for lithium, the ionic / electronic conductivity and the interface stability, and realize the uniform nucleation and reversible deposition of lithium ions, thereby significantly improving the energy density, cycle life and safety of the negative electrode-free all-solid-state battery.

[0004] To solve the above-mentioned technical problems, the present invention provides a negative electrode-free all-solid-state battery, comprising:

[0005] Positive electrode sheet; A negative electrode current collector, comprising a current collector substrate and a modification layer disposed on at least one surface of the current collector substrate, the modification layer comprising a high-entropy sulfide electrolyte; and A solid electrolyte layer is disposed between the positive electrode and the negative electrode current collector. The modification layer is close to the solid electrolyte layer. The solid electrolyte layer includes the high-entropy sulfide electrolyte, the chemical formula of which is: Li 4±x-y A y (M1 a M2 b M3 c S4 δ X δWherein, 0≤x≤1.5, 0≤y≤1.5, and y≤4±x; 0.4≤a≤0.8, 0.1≤b≤0.4, 0.1≤c≤0.3, a+b+c=1, 0≤δ≤1; A is selected from one or two of Na or K; M1 is selected from one or more of Ge, Sn, Si, P, As or B; M2 is selected from one or more of Sb, Nb, Ta, V, Mo, W, Ti, Zr, Hf or Re; M3 is selected from one or more of Al, Ga, In, Bi, Pb, Mg, Ca, Zn, Cd, Y, Sc, La, Ba, Sr, Ce or Sm; X is selected from one or more of O, Se or Te.

[0006] In one embodiment of the present invention, the median particle size of the high-entropy sulfide electrolyte is 500 nm to 5 μm; and / or, the ionic conductivity of the high-entropy sulfide electrolyte is 1 × 10⁻⁶. -3 S / cm to 2×10 -2 S / cm.

[0007] In one embodiment of the present invention, the median particle size of the high-entropy sulfide electrolyte is 1 μm to 3 μm.

[0008] In one embodiment of the present invention, when the modification layer is a single layer, the modification layer includes a first modification layer, the first modification layer including a carbon material, the high-entropy sulfide electrolyte, a lithiophilic substance and a binder, wherein the mass ratio of the carbon material, the high-entropy sulfide electrolyte and the lithiophilic substance is (50 to 90):(5 to 40):(1 to 15), and the binder accounts for 1 wt% to 5 wt% of the total mass of the carbon material, the high-entropy sulfide electrolyte and the lithiophilic substance.

[0009] In one embodiment of the present invention, the thickness of the first modified layer is 0.1 μm to 10 μm, and the areal loading of the first modified layer is 0.1 mg / cm³. 2 Up to 2 mg / cm 2 .

[0010] In one embodiment of the present invention, when the modification layer is multilayered, the modification layer includes a first modification layer and a second modification layer, the first modification layer is disposed on the current collector substrate, and the second modification layer is disposed on the side surface of the first modification layer away from the current collector substrate.

[0011] In one embodiment of the present invention, the first modification layer comprises a mixture of carbon material, high-entropy electrolyte and binder, wherein the mass ratio of the carbon material to the high-entropy electrolyte is (50 to 95):(5 to 50), and the binder accounts for 1 wt% to 5 wt% of the total mass of the carbon material and the high-entropy electrolyte; the second modification layer comprises a lithiophilic substance.

[0012] In one embodiment of the present invention, the thickness of the first modified layer is 0.1 μm to 10 μm, and the areal loading of the first modified layer is 0.1 mg / cm³. 2 Up to 2 mg / cm 2 The thickness of the second modification layer is 1 nm to 100 nm.

[0013] In one embodiment of the present invention, the carbon material is selected from one or more of graphene, graphite, carbon nanotubes, hard carbon, soft carbon, carbon nanofibers, carbon black, or MXene. The lithiophilic substance is selected from one or more of Ag, Al, Au, Sn, Zn, Ca, In, Ca, Pb, Bi, Mg, or alloys formed by each of the above elements with lithium.

[0014] The present invention also provides an electronic device comprising the aforementioned negative electrode-free all-solid-state battery.

[0015] In summary, this invention proposes a cathode-free all-solid-state battery and its applications. By forming a modification layer on the current collector, it achieves both high electronic conductivity and high ionic conductivity, forming an electron-ion dual-continuous network and significantly reducing interfacial charge transfer impedance. Furthermore, the modification layer induces uniform lithium nucleation. The high-entropy sulfide electrolyte, due to the severe lattice distortion and local disorder caused by the coexistence of multiple metal cations, forms numerous low-barrier lithium-ion migration paths, which can homogenize the lithium-ion flow and avoid excessively high local current densities. In the modification layer, the various cations mixed in the high-entropy sulfide electrolyte significantly reduce the system's Gibbs free energy, suppressing phase separation during high-temperature or electrochemical cycling. It acts as both an ionic conductor and a structural stabilizer, firmly bonding the lithiophilic layer to the carbon framework, preventing the modification layer from peeling off during cycling, and significantly improving the interfacial mechanical and electrochemical stability. By matching the modified negative electrode current collector with the solid electrolyte layer, the affinity of the negative electrode current collector for lithium, the ionic / electronic conductivity and interface stability are improved, and uniform nucleation and reversible deposition of lithium ions are achieved, thereby significantly improving the energy density, cycle life and safety of the negative electrode-free all-solid-state battery. Detailed Implementation

[0016] The following specific examples illustrate the implementation of the present invention. 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.

[0017] It should be understood that the invention can be embodied in various forms and should not be construed as being limited to the embodiments set forth herein. Rather, providing these embodiments will make the disclosure thorough and complete, and will fully convey the scope of the invention to those skilled in the art.

[0018] The technical solution of the present invention will be further described in detail below with reference to the embodiments. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0019] This invention proposes a negative electrode-free all-solid-state battery, comprising a positive electrode, a negative electrode current collector, and a solid electrolyte layer. The negative electrode current collector includes a current collector substrate and a modification layer disposed on at least one surface of the current collector substrate. The modification layer comprises a high-entropy sulfide electrolyte. The solid electrolyte layer is disposed between the positive electrode and the negative electrode current collector. The solid electrolyte layer comprises a high-entropy sulfide electrolyte with the chemical formula: Li. 4±x-y A y (M1 a M2 b M3 c S4 δ X δ Wherein, 0≤x≤1.5, 0≤y≤1.5, and y≤4±x; 0.4≤a≤0.8, 0.1≤b≤0.4, 0.1≤c≤0.3, a+b+c=1, 0≤δ≤1; A is selected from one or two of Na or K; M1 is selected from one or more of Ge, Sn, Si, P, As or B; M2 is selected from one or more of Sb, Nb, Ta, V, Mo, W, Ti, Zr, Hf or Re; M3 is selected from one or more of Al, Ga, In, Bi, Pb, Mg, Ca, Zn, Cd, Y, Sc, La, Ba, Sr, Ce or Sm; X is selected from one or more of O, Se or Te. By matching a negative electrode current collector with a high-entropy sulfide electrolyte with a solid electrolyte layer with a high-entropy sulfide electrolyte, the affinity of the negative electrode current collector for lithium, the ionic / electronic conductivity and interface stability are improved, and uniform nucleation and reversible deposition of lithium ions are achieved, thereby significantly improving the energy density, cycle life and safety of the negative electrode-free all-solid-state battery.

[0020] In this invention, the negative electrode-free all-solid-state battery is, for example, a primary battery or a secondary battery. The secondary battery is, for example, a pouch battery, a prismatic battery, or a cylindrical battery. This invention does not impose specific limitations on the types and categories of negative electrode-free all-solid-state batteries.

[0021] In one embodiment of the present invention, the median particle size D50 of the high-entropy sulfide electrolyte is, for example, 500 nm to 5 μm, or, for example, 1 μm to 3 μm. The median particle size D50 refers to the particle size corresponding to the cumulative distribution percentage reaching 50% in the particle size distribution of a volume-based particle group; that is, half of the particles in the sample have a particle size less than or equal to this value, and the other half have a particle size greater than or equal to this value. The ionic conductivity of the high-entropy sulfide electrolyte is 1 × 10⁻⁶. -3 S / cm to 2×10 -2 S / cm. In one embodiment of the present invention, the high-entropy sulfide electrolyte is cold-pressed at 300 MPa to 400 MPa to obtain a solid electrolyte layer with a thickness of, for example, 200 μm to 350 μm. The high-entropy sulfide electrolyte has high ionic conductivity, a wide electrochemical window, and excellent mechanical flexibility; due to the severe lattice distortion and local disorder caused by the coexistence of multiple metal cations, a large number of low-barrier lithium-ion migration paths are formed, which can homogenize the lithium-ion flow and avoid excessively high local current density.

[0022] In one embodiment of the present invention, the above-mentioned high-entropy sulfide electrolyte can be prepared by the following method: First, according to the chemical formula Li 4±x-y A y (M1 a M2 b M3 c S4 δ X δ The Li source, A source, M1 source, M2 source, M3 source, S source, and X source are mixed uniformly according to a stoichiometric ratio, then added to a ball mill jar for ball milling to obtain precursor powder. The precursor powder is sintered and cooled to obtain a high-entropy sulfide electrolyte. In a specific embodiment of the present invention, the Li source is, for example, derived from lithium sulfide or LiX, the A source is derived from the corresponding element's sulfide, the X source is derived from LiX, the M1, M2, and M3 sources are, for example, derived from the corresponding element's sulfide, and the S source is derived from lithium sulfide, the A source's sulfide, or the M source's sulfide, etc. In other embodiments, other substances can also be selected as raw materials. The ball-to-material mass ratio in the ball mill jar is, for example, 1:1 to 100:1, the ball milling time is, for example, 1 hour to 48 hours, and the ball milling speed is, for example, 50 rpm to 1500 rpm. The precursor powder obtained by ball milling is then sintered at a temperature of 150°C to 500°C for 1 to 12 hours, and then cooled at a rate of 1°C / s to 10°C / s to obtain a high-entropy sulfide electrolyte. All the above steps are carried out in an inert atmosphere such as argon during the preparation of the high-entropy sulfide electrolyte.

[0023] The preparation method of high-entropy sulfide electrolytes is not limited to this; other conventional methods for preparing sulfide electrolytes can also be used.

[0024] In one embodiment of the present invention, the negative electrode current collector includes a current collector substrate and a modification layer disposed on at least one surface of the current collector substrate. The current collector substrate is, for example, composed of one or more of copper, stainless steel, or nickel, and the modification layer is, for example, at least one layer, with a thickness of, for example, 6 μm to 12 μm. In one embodiment of the present invention, when the modification layer is a single layer, the modification layer includes a first modification layer comprising a carbon material, the aforementioned high-entropy sulfide electrolyte, a lithiophilic substance, and a binder, with a mass ratio of, for example, (50 to 90):(5 to 40):(1 to 15), and the binder, for example, accounts for 1 wt% to 5 wt% of the total mass of the carbon material, high-entropy sulfide electrolyte, and lithiophilic substance. The thickness of the first modification layer is, for example, 0.1 μm to 10 μm, and the areal loading of the first modification layer is, for example, 0.1 mg / cm³. 2 Up to 2 mg / cm 2 The compaction density is, for example, 0.2 g / cm³. 3 Up to 4g / cm 3 .

[0025] In one embodiment of the present invention, when the modification layer is multilayered, the modification layer includes, for example, a first modification layer and a second modification layer. The first modification layer is disposed on the current collector substrate, and the second modification layer is disposed on the surface of the first modification layer away from the current collector substrate. The first modification layer comprises a mixture of carbon material, high-entropy sulfide electrolyte, and binder, wherein the mass ratio of carbon material to high-entropy sulfide electrolyte is, for example, (50 to 95):(5 to 50), and the binder accounts for, for example, 1 wt% to 5 wt% of the total mass of carbon material and high-entropy sulfide electrolyte. The second modification layer comprises a lithiophilic material. The thickness of the first modification layer is, for example, 0.1 μm to 10 μm, and the areal loading of the first modification layer is, for example, 0.1 mg / cm². 2 Up to 2 mg / cm 2 The compaction density is, for example, 1 mg / cm³. 3 Up to 3mg / cm 3The thickness of the second modification layer is, for example, 1 nm to 100 nm. By constructing a single-layer or double-layer modification structure on the current collector surface, consisting of carbon materials, a high-entropy sulfide electrolyte, and a lithiophilic material layer, the affinity of the negative electrode current collector for lithium, ionic / electronic conductivity, and interfacial stability are synergistically improved. Simultaneously, the excellent ion transport performance and structural stability of the high-entropy sulfide electrolyte are utilized to achieve uniform nucleation and reversible deposition of lithium ions, thereby significantly improving the energy density, cycle life, and safety of the electrodeless all-solid-state battery. Furthermore, the high-entropy design allows for the control of Young's modulus and fracture toughness, resulting in a negative electrode current collector with a certain degree of plasticity to adapt to low-pressure (e.g., 1 MPa to 5 MPa) stacking. Under low stacking pressure, the interfacial contact between the negative electrode current collector and the solid electrolyte layer is significantly improved, reducing interfacial impedance and significantly enhancing the battery's initial coulombic efficiency, cycle stability, and rate performance. The electrodeless all-solid-state battery retains ≥85% capacity after 300 cycles at 1C / 1C and ≥60% at 4C rate.

[0026] In this invention, a high-entropy sulfide electrolyte is composited with carbon materials, exhibiting both high electronic and ionic conductivity to form an electron-ion bicontinuous network, significantly reducing interfacial charge transfer impedance. Furthermore, the lithiophilic layer or lithiophilic material induces uniform lithium nucleation, while the high-entropy sulfide electrolyte, due to the coexistence of multiple metal cations causing severe lattice distortion and local disorder, forms numerous low-barrier lithium-ion migration pathways, homogenizing the lithium-ion flow and preventing excessively high local current densities. In the modification layer, the various cations mixed in the high-entropy sulfide electrolyte significantly reduce the system's Gibbs free energy, suppressing phase separation during high-temperature or electrochemical cycling. It acts as both an ionic conductor and a structural stabilizer, firmly bonding the lithiophilic layer to the carbon framework, preventing delamination of the modification layer during cycling, and greatly improving the interfacial mechanical and electrochemical stability.

[0027] In one embodiment of the present invention, the carbon material is selected from one or more of graphene, graphite, carbon nanotubes, hard carbon, soft carbon, vapor-grown carbon fiber (VGCF), carbon black, or MXene, and is also selected from one or more of graphene, graphite, and MXene, or is a mixture of graphite and graphene or a mixture of graphite and MXene. The lithiophilic material is selected from one or more of Ag, Al, Au, Sn, Zn, Ca, In, Ca, Pb, Bi, Mg, or alloys formed by the above elements with lithium. Adhesives are selected from, for example, polyvinylidene fluoride (PVDF), carboxymethyl cellulose (CMC), polymerized styrene-butadiene rubber (SBR), polyvinylpyrrolidone (PVP), polymethyl methacrylate (PMMA), polyacrylonitrile (PAN), polyacrylic acid (PAA), polyurethane (PU), polyvinyl alcohol (PVA), sodium alginate (Alg), ethylene-propylene-diene monomer (EPDM), fluororubber, and β-cyclodextrin polymers. Polymer (β-CDp), polypropylene emulsion (LA132), polytetrafluoroethylene (PTFE), ethylene-tetrafluoroethylene copolymer (ETFE), fluorinated ethylene-propylene copolymer (FEP), perfluoroalkoxy alkane (PFA), polychlorotrifluoroethylene (PCTFE), ethylene-chlorotrifluoroethylene copolymer (ECTFE), polyvinylidene fluoride-hexafluoropropylene copolymer (PVDF-HFP), polyvinylidene fluoride-trifluorochloroethylene copolymer (PVDF-CTFE), and one or more of the following:

[0028] In one embodiment of the present invention, when the modification layer is a single layer, for example, carbon material, high-entropy sulfide electrolyte, lithiophilic substance and binder are thoroughly mixed in xylene solvent according to a mass ratio to obtain a first modification layer slurry, which is then coated onto the current collector substrate and dried and cold-pressed to obtain a negative electrode current collector. When the modification layer is multilayer, for example, the first modification layer or the second modification layer is formed by one or more of magnetron sputtering, atomic layer deposition (ALD), spraying, spin coating or blade coating.

[0029] In one embodiment of the present invention, the positive electrode sheet includes a positive current collector and a positive active layer coated on at least one surface of the positive current collector. The positive current collector is, for example, a foil formed by surface treatment of materials such as nickel, titanium, aluminum, silver, stainless steel, or carbon. Besides foil, the positive current collector can also be used in any one or more combinations of various forms such as film, mesh, porous, foam, or nonwoven fabric.

[0030] In one embodiment of the present invention, the positive electrode active layer includes a positive electrode active material, the aforementioned high-entropy sulfide electrolyte, a positive electrode conductive agent, and a positive electrode binder. The positive electrode active material includes, for example, at least one of lithium nickel cobalt manganese oxide (NCM), lithium nickel oxide (LNO), lithium manganese oxide (LMO), lithium nickel manganese oxide (LNMO), lithium cobalt oxide (LCO), or lithium nickel cobalt aluminum oxide (NCA). The positive electrode conductive agent is selected from at least one of conductive carbon black, acetylene black, carbon fiber, carbon nanotubes, or graphene. The positive electrode binder is selected from at least one of polyvinylidene fluoride, polytetrafluoroethylene, hydrogenated nitrile rubber (HNBR), poly(ethylene oxide) (PEO), polyamide (PA), polyacrylonitrile (PAN), polyacrylate, polyethylene ether, polymethyl methacrylate (PMMA), ethylene-propylene-diene terpolymer (EPDM), or polyhexanefluoropropylene (Polyhexafluoropropylene). The mass ratio of the positive electrode active material, high-entropy sulfide electrolyte, positive electrode conductive agent, and positive electrode binder is, for example, (60 to 94):(5 to 30):(1 to 5):(1 to 5).

[0031] In a specific embodiment of the present invention, the positive electrode active material is selected as LiNi. 0.8 Co 0.1 Mn 0.1O2, carbon fiber is selected as the positive electrode conductive agent, and hydrogenated nitrile rubber is selected as the positive electrode binder. The positive electrode active material, high entropy sulfide electrolyte, positive electrode conductive agent and positive electrode binder are thoroughly mixed in xylene solvent at a mass ratio of 70:25:2:3 to obtain a positive electrode slurry. The slurry is coated on aluminum foil, dried and cold pressed to obtain a positive electrode sheet.

[0032] In one embodiment of the present invention, when obtaining a negative electrode-free all-solid-state battery, the positive electrode and the negative electrode current collector are placed on opposite sides of the solid electrolyte layer. When the modification layer is disposed on one side of the current collector substrate, the modification layer in the negative electrode current collector faces the solid electrolyte layer. After assembly and sealing, the battery is pressed under isobaric pressure at 500 MPa to obtain a negative electrode-free all-solid-state battery. The assembly process of the negative electrode-free all-solid-state battery is completed in an inert atmosphere.

[0033] The present invention will be explained in more detail below by referring to embodiments, which should not be construed as limiting. Appropriate modifications can be made within the scope of the present invention, and all such modifications fall within the technical scope of the present invention.

[0034] Example 1 Preparation of high-entropy sulfide electrolyte: Under an argon atmosphere, 1.835 mol of Li₂S, 0.06 mol of SnS₂, 0.21 mol of SiS₂, 0.165 mol of P₂S₅, 0.1 mol of Sb₂S₅, and 0.1 mol of Al₂S₃ were placed in a ball mill jar. Ball milling beads were added at a ball-to-material mass ratio of 30:1. The mixture was ball-milled at 100 rpm for 10 min, followed by further ball milling at 600 rpm for 16 h to obtain a homogeneous precursor powder. The precursor powder was then placed in a crucible and sintered at 200 °C for 20 h. After cooling at a rate of 5 °C / s, Li₂S₅ was obtained. 3.67 (Sn 0.1 Si 0.35 P 0.55 ) 0.6 Sb 0.2 Al 0.2 S4 electrolyte material, and Li with a median particle size D50 of 2 μm was obtained by sieving. 3.67 (Sn 0.1 Si 0.35 P 0.55 ) 0.6 Sb 0.2 Al 0.2 S4 electrolyte material.

[0035] Preparation of negative electrode current collector: The above Li 3.67 (Sn 0.1 Si 0.35 P 0.55 ) 0.6 Sb0.2 Al 0.2 S4, carbon materials, and Ag were dry-mixed at a mass ratio of 15:80:5 for 2 hours to obtain a mixed modification layer material. The carbon materials consisted of graphite and graphene mixed at a mass ratio of 98.5:1.5. Then, 50 wt% of the mixed modification layer material, 2 wt% of SBR binder, and 48 wt% of xylene were mixed evenly to obtain a first modification layer slurry. This modification layer slurry was coated onto one side of an 8 μm thick copper current collector and dried to obtain a negative electrode current collector with the first modification layer. The areal loading of the first modification layer was 1.5 mg / cm³. 2 The compacted density is 2 g / cm³. 3 The thickness is 7.5μm, and it is cut into round pieces with a diameter of 10mm.

[0036] Preparation of solid electrolyte layer: 50 mg of the above-mentioned Li 3.67 (Sn 0.1 Si 0.35 P 0.55 ) 0.6 Sb 0.2 Al 0.2 S4 was cold-pressed at 360 MPa to prepare a solid electrolyte layer with a thickness of 300 μm and a diameter of 10 mm.

[0037] Preparation of positive electrode: LiNi 0.8 Co 0.1 Mn 0.1 O2, Li 3.67 (Sn 0.1 Si 0.35 P 0.55 ) 0.6 Sb 0.2 Al 0.2 S4, carbon fiber, and hydrogenated nitrile rubber were thoroughly mixed in xylene solvent at a mass ratio of 70:25:2:3 to obtain a positive electrode slurry. This slurry was coated onto aluminum foil, dried, and cold-pressed to obtain the positive electrode sheet. The areal capacity of the positive electrode sheet was 4 mAh / cm². 2 And cut it into round pieces with a diameter of 10mm.

[0038] Assembly of a negative electrode-free all-solid-state battery: Under an argon atmosphere, the above-mentioned positive electrode and negative electrode current collector are placed on both sides of the solid electrolyte layer, assembled, sealed, and pressed under isobaric pressure at 500MPa to obtain a negative electrode-free all-solid-state battery.

[0039] Example 2 In the preparation of high-entropy sulfide electrolytes, the raw materials were 1.95 mol Li₂S, 0.6 mol SiS₂, 0.05 mol Sb₂S₅, 0.04 mol MoS₃, 0.06 mol WS₃, and 0.1 mol Al₂S₃, yielding Li₂S electrolytes with a median particle size D₅₀ of 2 μm. 3.9 Si 0.6 (Sb 0.5 Mo 0.2 W 0.3 ) 0.2 Al 0.2 S4 electrolyte material. The Li obtained in this embodiment was used in the preparation of the positive electrode, negative electrode current collector, and solid electrolyte layer. 3.9 Si 0.6 (Sb 0.5 Mo 0.2 W 0.3 ) 0.2 Al 0.2 The S4 electrolyte material is the same as in Example 1, except for the other steps.

[0040] Example 3 In the preparation of high-entropy sulfide electrolytes, the raw materials were 2.02 mol Li₂S, 0.6 mol SiS₂, 0.1 mol Sb₂S₅, 0.03 mol Al₂S₃, 0.05 mol In₂S₃, and 0.04 mol SrS, yielding Li₂S electrolytes with a median particle size D₅₀ of 2 μm. 4.04 Si 0.6 Sb 0.2 (In 0.5 Al 0.3 Sr 0.2 ) 0.2 S4 electrolyte material. The Li obtained in this embodiment was used in the preparation of the positive electrode, negative electrode current collector, and solid electrolyte layer. 4.04 Si 0.6 Sb 0.2 (In 0.5 Al 0.3 Sr 0.2 ) 0.2 The S4 electrolyte material is the same as in Example 1, except for the other steps.

[0041] Example 4 In the preparation of high-entropy sulfide electrolytes, the raw materials were 1.9 mol Li₂S, 0.05 mol Na₂S, 0.05 mol K₂S, 0.6 mol SiS₂, 0.1 mol Sb₂S₅, and 0.1 mol Al₂S₃, yielding Li₂S electrolytes with a median particle size D₅₀ of 2 μm. 3.8 Na 0.1 K 0.1 Si 0.6Sb 0.2 Al 0.2 S4 electrolyte material. The Li obtained in this embodiment was used in the preparation of the positive electrode, negative electrode current collector, and solid electrolyte layer. 3.8 Na 0.1 K 0.1 Si 0.6 Sb 0.2 Al 0.2 The S4 electrolyte material is the same as in Example 1, except for the other steps.

[0042] Example 5 In the preparation of high-entropy sulfide electrolytes, the raw materials were 1.7 mol Li₂S, 0.6 mol SiS₂, 0.1 mol Sb₂S₅, 0.1 mol Al₂S₃, 0.2 mol Li₂O, and 0.1 mol Li₂Te, yielding Li₄Si with a median particle size D₅₀ of 2 μm. 0.6 Sb 0.2 Al 0.2 S 3.7 O 0.2 Te 0.1 Electrolyte material. The Li4Si obtained in this embodiment was used in the preparation of the positive electrode, negative electrode current collector, and solid electrolyte layer. 0.6 Sb 0.2 Al 0.2 S 3.7 O 0.2 Te 0.1 The electrolyte material and other steps are the same as in Example 1.

[0043] Example 6 When preparing the negative electrode current collector, Li 4.04 Si 0.6 Sb 0.2 (In 0.5 Al 0.3 Sr 0.2 ) 0.2 S 44 The mass ratio of carbon material to Ag is 15:80:5. The carbon material is a mixture of graphite and graphene in a mass ratio of 1.5:98.5. The other steps are the same as in Example 3.

[0044] Example 7 When preparing the negative electrode current collector, Li 4.04 Si 0.6 Sb 0.2 (In 0.5 Al 0.3 Sr 0.2 ) 0.2 S 44The mass ratio of carbon material to Ag is 15:80:5. The carbon material is a mixture of graphite and graphene in a mass ratio of 50:50. The other steps are the same as in Example 3.

[0045] Example 8 When preparing the negative electrode current collector, Li 4.04 Si 0.6 Sb 0.2 (In 0.5 Al 0.3 Sr 0.2 ) 0.2 S 44 The mass ratio of carbon material to Ag is 15:80:5, and the carbon material is graphite. Other steps are the same as in Example 3.

[0046] Example 9 When preparing the negative electrode current collector, Li 4.04 Si 0.6 Sb 0.2 (In 0.5 Al 0.3 Sr 0.2 ) 0.2 S 44 The mass ratio of carbon material to Ag is 15:80:5, and the carbon material is graphene. Other steps are the same as in Example 3.

[0047] Example 10 When preparing the negative electrode current collector, Li 4.04 Si 0.6 Sb 0.2 (In 0.5 Al 0.3 Sr 0.2 ) 0.2 S 44 The mass ratio of carbon material to Ag is 15:80:5, and the carbon material is VGCF. Other steps are the same as in Example 3.

[0048] Example 11 When preparing the negative electrode current collector, Li 4.04 Si 0.6 Sb 0.2 (In 0.5 Al 0.3 Sr 0.2 ) 0.2 S 44 The mass ratio of carbon material to Ag is 5:90:5. The carbon material is a mixture of graphite and graphene in a mass ratio of 98.5:1.5. The other steps are the same as in Example 3.

[0049] Example 12 When preparing the negative electrode current collector, Li 4.04 Si 0.6Sb 0.2 (In 0.5 Al 0.3 Sr 0.2 ) 0.2 S 44 The mass ratio of carbon material to Ag is 40:55:5. The carbon material is a mixture of graphite and graphene in a mass ratio of 98.5:1.5. The other steps are the same as in Example 3.

[0050] Example 13 When preparing the negative electrode current collector, Li 4.04 Si 0.6 Sb 0.2 (In 0.5 Al 0.3 Sr 0.2 ) 0.2 S 44 The mass ratio of carbon material to Ag is 15:84:1. The carbon material is a mixture of graphite and graphene in a mass ratio of 98.5:1.5. The other steps are the same as in Example 3.

[0051] Example 14 When preparing the negative electrode current collector, Li 4.04 Si 0.6 Sb 0.2 (In 0.5 Al 0.3 Sr 0.2 ) 0.2 S 44 The mass ratio of carbon material to Ag is 15:70:15. The carbon material is a mixture of graphite and graphene in a mass ratio of 98.5:1.5. The other steps are the same as in Example 3.

[0052] Example 15 The median particle size D50 of the high-entropy sulfide electrolyte is 500 nm, and the other steps are the same as in Example 3.

[0053] Example 16 The median particle size D50 of the high-entropy sulfide electrolyte is 1 μm, and the other steps are the same as in Example 3.

[0054] Example 17 The median particle size D50 of the high-entropy sulfide electrolyte is 3 μm, and the other steps are the same as in Example 3.

[0055] Example 18 The median particle size D50 of the high-entropy sulfide electrolyte is 5 μm, and the other steps are the same as in Example 3.

[0056] Example 19 The median particle size D50 of the high-entropy sulfide electrolyte is 7 μm, and the other steps are the same as in Example 3.

[0057] Example 20 Preparation of negative electrode current collector: Li 4.04 Si 0.6 Sb 0.2 (In 0.5 Al 0.3 Sr 0.2 ) 0.2 S4 and carbon materials were dry-mixed at a mass ratio of 50:50 for 2 hours to obtain a mixed modification layer material. The carbon material consisted of graphite and graphene mixed at a mass ratio of 98.5:1.5. Then, 50 wt% of the mixed modification layer material, 2 wt% of SBR binder, and 48 wt% of xylene were mixed evenly to obtain a first modification layer slurry. The first modification layer slurry was coated onto one side of a copper current collector and dried to obtain a material with the first modification layer. The areal loading of the first modification layer was 1.5 mg / cm³. 2 The compacted density is 2 g / cm³. 3 The thickness is 7.5 μm. A second modification layer is formed by sputtering a 40 nm thick Ag layer onto the first modification layer using magnetron sputtering, and then cut into 10 mm diameter wafers. Other steps are the same as in Example 3.

[0058] Example 21 During the preparation of the first modification layer, Li 4.04 Si 0.6 Sb 0.2 (In 0.5 Al 0.3 Sr 0.2 ) 0.2 S 44 The mass ratio of graphite to carbon material is 15:85, and the carbon material is a mixture of graphite and graphene at a mass ratio of 98.5:1.5. Other steps are the same as in Example 20.

[0059] Example 22 During the preparation of the first modification layer, Li 4.04 Si 0.6 Sb 0.2 (In 0.5 Al 0.3 Sr 0.2 ) 0.2 S 44 The mass ratio of graphite to carbon material is 5:95, and the carbon material is a mixture of graphite and graphene at a mass ratio of 98.5:1.5. Other steps are the same as in Example 20.

[0060] Example 23 The second modification layer is Sn, and the other steps are the same as in Example 21.

[0061] Example 24 The second modification layer is Mg, and the other steps are the same as in Example 21.

[0062] Example 25 The second modification layer is Ag with a thickness of 1 nm, and the other steps are the same as in Example 21.

[0063] Example 26 The second modification layer is Ag with a thickness of 100 nm, and the other steps are the same as in Example 21.

[0064] Example 27 The thickness of the second modified Ag layer is 1 μm, and the other steps are the same as in Example 21.

[0065] Comparative Example 1 In preparing the high-entropy sulfide electrolyte, the raw materials were 2 mol of Li₂S and 1 mol of SnS₂, yielding Li₄SnS₄ electrolyte material. Li₄SnS₄ electrolyte material was used in the preparation of the positive electrode, negative current collector, and solid electrolyte layer; other steps were the same as in Example 3.

[0066] Comparative Example 2 Carbon materials and Ag were dry-mixed at a mass ratio of 94:6 for 2 hours to obtain a mixed modification layer material. The carbon materials consisted of graphite and graphene mixed at a mass ratio of 98.5:1.5. Then, 50 wt% of the mixed modification layer material, 2 wt% of SBR binder, and 48 wt% of xylene were mixed evenly to obtain a first modification layer slurry. This first modification layer slurry was coated onto one side of a copper current collector and dried to obtain a negative electrode current collector with the first modification layer. The areal loading of the first modification layer was 1.5 mg / cm³. 2 The compacted density is 2 g / cm³. 3 The thickness is 7.5 μm, and it is cut into circular pieces with a diameter of 10 mm. The other steps are the same as in Example 3.

[0067] Comparative Example 3 Graphite and graphene were dry-mixed at a mass ratio of 98.5:1.5 for 2 hours to obtain a mixed modification layer material. Then, 50 wt% of the mixed modification layer material, 2 wt% of SBR binder, and 48 wt% of xylene were mixed evenly to obtain a first modification layer slurry. The first modification layer slurry was coated onto one side of a copper current collector and dried to obtain the first modification layer. A second modification layer was formed by sputtering 40 nm of Ag onto the first modification layer using magnetron sputtering. The areal loading of the first modification layer was 1.5 mg / cm². 2 The compacted density is 2 g / cm³. 3 The thickness is 7.5 μm, and it is cut into circular pieces with a diameter of 10 mm. The other steps are the same as in Example 3.

[0068] Comparative Example 4 Without setting a second modification layer, the other steps are the same as in Example 21.

[0069] In one embodiment of the present invention, the median particle size D50 is measured using a HELOS-RODOS type dry laser particle size analyzer.

[0070] In this invention, some characteristics of the high-entropy sulfide electrolyte and negative electrode current collector in Examples 1-27 and Comparative Examples 1-4 are shown in Table 1. The performance of the negative electrode-free all-solid-state batteries in Examples 1-27 and Comparative Examples 1-4 was tested, and the test results were recorded. The test results are shown in Table 2.

[0071] Table 1 shows some parameters of the high-entropy sulfide electrolyte and negative electrode current collector in Examples 1-27 and Comparative Examples 1-4.

[0072] In one embodiment of the present invention, to obtain room temperature cycling performance, at 25°C, a low pressure of 1 MPa was applied to the electrodeless all-solid-state batteries prepared in the examples and comparative examples. After activation at a rate of 0.05C for two cycles within an operating voltage range of 2.5V to 4.3V, charge and discharge were performed at a charge / discharge rate of 1C / 1C (1C rated current density is 4 mA / cm²). 2 Record the discharge capacity of the battery in the first cycle after activation, which is the first 1C discharge capacity Q0. Record the capacity after 300 battery cycles as Q1. Calculate the capacity retention rate after 1000 cycles of 1C / 1C at room temperature using the following formula: Capacity retention rate after 300 cycles = (Q1 / Q0) × 100%.

[0073] In one embodiment of the present invention, to obtain the Direct Current Resistance (DCR) at 50% State of Charge (50% SOC), the temperature of the temperature chamber is kept constant at 25°C. The all-solid-state battery without a negative electrode obtained in the embodiment and the comparative example is placed in the temperature chamber for 10 minutes. The battery is then charged at a constant current rate of 0.33C to 4.3V, followed by a constant voltage rate of 0.05C. After standing for 10 minutes, it is discharged at 0.33C to 2.5V to obtain the theoretical capacity of the battery. Subsequently, it is charged again at a constant current rate of 0.33C to 4.3V, followed by a constant voltage rate of 0.05C. After standing for 10 minutes, it is discharged at 0.33C to adjust the capacity to 50% SOC. After standing for 1 hour, the initial voltage V1 of the battery is recorded. Then, the battery is discharged at a current of 4C I0 for 30 seconds, and the battery voltage V2 after discharge is recorded. The DCR of the battery at 50% SOC is calculated according to the following formula: DCR(Ω)=(V1-V2) / I0.

[0074] In one embodiment of the present invention, the rate performance test is conducted at 25°C by applying a low pressure of 3 MPa to the electrodeless all-solid-state batteries assembled in the examples and comparative examples, at a rate of 0.05C (1C rated current density is 4 mA / cm²). 2 After two cycles of activation at the high rate, charge at 0.33C to 4.3V and let stand for 5 minutes. Then, discharge at different rates (e.g., 0.33C, 0.5C, 1C, 4C) to 2.5V. The specific process is as follows: charge at 0.33C, then discharge at 0.33C, repeat 3 times, and record the average discharge capacity at 0.33C; then charge at 0.33C and discharge at 0.5C, repeat 3 times; then charge at 0.33C and discharge at 1C, repeat 3 times; then charge at 0.33C and discharge at 4C, repeat 3 times, and record the average discharge capacity at 4C. Calculate the fast charging capacity retention rate at the high rate of 4C using the following formula: Fast charging capacity retention rate (%) = (Average discharge capacity at 4C / Average discharge capacity at 0.33C) × 100%.

[0075] Table 2 shows the performance of the electrodeless all-solid-state batteries in Examples 1-27 and Comparative Examples 1-4.

[0076] Please refer to Tables 1 and 2. Comparing Examples 1 to 5, 20 to 22, and Comparative Examples 1 to 3, it can be seen that the composition and performance of the sulfide electrolyte in the modification layer on the negative electrode current collector directly determine the cycle stability and fast-charging capability of the negative electrode-less all-solid-state battery. Specifically, when a traditional non-high-entropy sulfide electrolyte (such as Li4SnS4) is used in Comparative Example 1, the battery exhibits poor room-temperature cycle performance and fast-charging cycle performance, and a high DC impedance. This is due to the poor interfacial compatibility between the negative electrode current collector and the solid electrolyte layer, low ionic conductivity, and easy structural degradation, leading to uneven lithium deposition, a high risk of dendrite penetration, and rapid deterioration of electrochemical performance. When the modification layer does not contain a sulfide electrolyte, as in Comparative Examples 2 and 3, the modification layer loses its ion-conducting framework and interfacial stabilizing effect, resulting in uneven lithium deposition, easy dendrite formation, and a sharp deterioration in performance. In contrast, Examples 1 to 5 and 20 to 22 all employ high-entropy sulfide electrolytes. The multi-element synergistic effect endows the modified layer with excellent ion transport capability, chemical / mechanical stability, and interfacial compatibility with lithium metal. It can effectively guide uniform lithium nucleation and reversible deposition, thereby increasing the cycle retention rate of the electrodeless all-solid-state battery to over 90%, reducing DCR, and increasing the 4C fast charging retention rate to over 60%, significantly improving the performance of the electrodeless all-solid-state battery.

[0077] Please refer to Tables 1 and 2. Comparing Examples 3, 6 to 10, it can be seen that the battery performance is optimal when the carbon material in the modification layer is a composite of graphite and graphene. This is because graphene has a unique two-dimensional sheet structure and high specific surface area. On the one hand, graphene forms a continuous, highly conductive electron transport network on the current collector surface; on the other hand, the lateral size and surface functional groups of graphene can effectively regulate the lithium-ion flux distribution, inducing lithium ions to achieve two-dimensional uniform nucleation at the modification layer / electrolyte interface and suppressing dendrite protrusions. At the same time, graphite provides structural support, preventing excessive graphene stacking and maintaining the porous structure to promote ion diffusion. When the graphene content deviates from the optimal ratio, the electronic conductivity and interface regulation capability become unbalanced. When there is insufficient graphene, the conductive network becomes discontinuous, and the ion flow regulation is weak; excessive graphene easily leads to overly dense sheet stacking, hindering the vertical transport of lithium ions and reducing effective deposition sites. Both of these result in a slight deterioration in cycle stability and rate performance. When the graphite / graphene system is completely replaced by one-dimensional vapor-grown carbon fibers (VGCF), although VGCF has high intrinsic electronic conductivity and good mechanical strength, it lacks the two-dimensional planar confinement effect and in-plane ion current homogenization capability. Furthermore, the network formed by VGCF is mainly based on point-line contacts, and it cannot construct a large-area, continuous "ion sieve" structure on the current collector surface like graphene. This causes lithium ions to preferentially deposit at local high-curvature sites (such as fiber intersections), leading to non-uniform lithium metal growth. This results in deviations in the electrochemical performance of the battery, reflecting significantly weaker ion transport kinetics and interfacial stability compared to the graphite and graphene composite system.

[0078] Please refer to Tables 1 and 2. Comparing Examples 3, 11, and 14, it can be seen that when the proportions of high-entropy sulfide electrolyte, carbon material, and lithiophilic material in the modified layer are different, the room-temperature cycle performance, fast-charge cycle performance, and DC impedance of the battery differ. Example 3 achieves optimal synergy among the three components, which is due to the high-entropy sulfide electrolyte constructing a highly efficient Li-type battery. + In the transport channel, graphite and graphene form a continuous electronic network and homogenize the ion flow through their two-dimensional structure. An appropriate amount of Ag provides sufficient low-barrier nucleation sites. These three elements work together to promote uniform and dense lithium deposition, thus exhibiting the highest cycle retention rate and 4C fast-charging performance. In contrast, in Example 11, the increased proportion of carbon material, while enhancing electronic conductivity, dilutes the ion conduction network, resulting in poor interfacial Li... + Insufficient flux leads to a decrease in rate performance; in Example 12, the reduced proportion of carbon material results in a discontinuous electron conduction path, affecting the graphene's effect on Li. +The homogenization effect of the flow is weakened. Although the electrolyte is sufficient, the electron-ion coupling transport is hindered, which also limits high-rate performance. In Example 13, the proportion of lithiophilic material is low, resulting in insufficient lithiophilic sites, an increased lithium nucleation barrier, uneven initial deposition, and dendrite tendency, manifested as increased DCR and decreased fast-charging performance. In Example 14, the proportion of carbon material is reduced and the proportion of lithiophilic material is increased. Although lithiophilicity is enhanced, excess Ag occupies the interfacial space, crowding out the volume of the electrolyte and carbon phase, disrupting the ion / electron bicontinuous network, and high-cost metal agglomeration may cause local current concentration, reducing cycle stability. Therefore, controlling the proportion of high-entropy sulfide electrolyte, carbon material, and lithiophilic material in the modification layer to construct an ion-electron bicontinuous network is necessary to optimize Li + Improvements in transport, electronic conductivity, and uniformity of lithium deposition enhance the overall performance of the battery.

[0079] Please refer to Tables 1 and 2. Comparing Examples 3, 15 to 19, it can be seen that as the median particle size D50 of the high-entropy sulfide electrolyte increases, the room-temperature cycle capacity retention and fast-charge capacity retention of the battery first increase and then decrease, while the DC resistance first decreases and then increases. This is because when the median particle size D50 of the high-entropy sulfide electrolyte is moderate, the high-entropy sulfide electrolyte can form a dense and uniform composite structure with the carbon materials and Ag particles in the modification layer, constructing a continuous low-resistance Li... + The conductive network also facilitates good interface adhesion during electrode pressing. When the particle size decreases to 500 nm, the specific surface area of ​​the particles increases dramatically, making them prone to aggregation and difficult to disperse uniformly in the modification layer. This leads to disordered pore structure, uneven interface contact, tortuous ion transport paths, increased DCR, and decreased fast-charging performance. When the particle size increases to 5 μm or 7 μm, large particles cannot fill the gaps in the micron-sized carbon / Ag framework, resulting in "point contact" rather than "surface contact" between the electrolyte and the current collector. This significantly reduces the effective ion conduction area, increases the interface impedance significantly, and leads to highly localized lithium deposition, causing dendrite risk and a sharp deterioration in cycle and rate performance. Therefore, by controlling the median particle size D50 of the high-entropy sulfide electrolyte, a dense and uniform composite structure can be formed to construct a continuous low-resistivity Li-2000 lithium-ion battery. + Conductive networks reduce interfacial impedance and improve the uniformity of lithium deposition.

[0080] Please refer to Tables 1 and 2. Comparing Example 2022 and Comparative Example 3, it can be seen that when a double-layer modification layer is provided, the ratio of high-entropy sulfide electrolyte to carbon material in the first modification layer affects the battery performance. In this application, in Example 21, the ratio of high-entropy sulfide electrolyte to carbon material is moderate, and the battery performance is optimal. This is because the high-entropy sulfide electrolyte is uniformly dispersed in a high-proportion carbon network, which is sufficient to provide the necessary Li. +Transport path; the dominant graphite and graphene not only construct a highly conductive framework, but the two-dimensional sheet structure of graphene also more effectively guides the uniform distribution of lithium ion flow and provides abundant nucleation sites for lithium deposition, while suppressing dendrite penetration, thus achieving efficient synergy between ion conduction and interface regulation functions. In Example 20, the proportion of high-entropy sulfide electrolyte was too high, diluting the continuity of the carbon network, weakening the electronic conduction ability and the regulatory effect of graphene on ion flow, resulting in a decrease in fast charging performance. In Example 22, the content of high-entropy sulfide electrolyte was too low, making it difficult to form an effective ion conduction pathway, Li + Transport is hindered, interfacial polarization increases, and cycle stability decreases. In Comparative Example 3, the high-entropy sulfide electrolyte is completely absent, and Li is not present. + The conductive framework also lacks the interfacial stabilizing effect of high-entropy sulfide electrolytes. Lithium deposition relies entirely on the Ag surface, which is prone to uneven growth, resulting in high internal resistance, rapid capacity decay, and extremely poor fast charging capability.

[0081] Please refer to Tables 1 and 2. Comparing Examples 20, 23, and 24 with Comparative Example 4, it can be seen that when Ag, Sn, and Mg are used as the lithiophilic layers for the second modification, they all exhibit excellent cycle stability and low interfacial impedance. This is because these metals can significantly reduce the lithium nucleation overpotential, provide high-density, low-barrier heterogeneous nucleation sites, guide lithium to deposit uniformly and densely on the current collector surface, and effectively suppress dendrite growth. When the modification layer does not contain any lithiophilic metal layer, it relies solely on carbon materials and sulfide electrolytes, resulting in a lack of effective nucleation induction for lithium ions at the interface between the negative electrode current collector and the solid electrolyte layer. The initial deposition is prone to forming irregular, loose, or sharp lithium structures, causing local current concentration and interfacial side reactions, resulting in a sharp increase in interfacial impedance, rapid capacity decay, and severe deterioration of fast-charging capability.

[0082] Please refer to Tables 1 and 2. Comparing Examples 21, 25 to 27, it can be seen that as the thickness of the second modification layer increases, the room-temperature cycle capacity retention and fast-charging capacity retention of the battery first increase and then decrease, while the DC resistance first decreases and then increases. This is because a second modification layer of appropriate thickness can provide sufficient lithiophilic nucleation sites while maintaining a good ion / electron transport interface, achieving uniform and dense lithium deposition. When the second modification layer is too thin, such as 1 nm, although it still contains lithiophilic materials, the coverage of the second modification layer is discontinuous, and there are insufficient effective nucleation sites, leading to localized lithium deposition, increased dendrite tendency, and a significant decrease in cycle stability and rate performance. When the second modification layer is too thick, although the lithiophilicity is enhanced, the excessively thick lithiophilic material will block the direct contact between the solid electrolyte layer and the current collector, increase the ion transport path length, and may cause interface peeling due to volume expansion, resulting in increased DCR and accelerated capacity decay. Therefore, controlling the thickness of the second modification layer is crucial to synergistically balance ion-electron transport and lithium deposition.

[0083] This invention also provides an electronic device comprising at least one of the aforementioned negative-electrode all-solid-state batteries, which provides electrical energy. The electronic device can be a vehicle, mobile phone, portable device, laptop, ship, spacecraft, electric toy, or power tool, etc. In one embodiment of this invention, the vehicle is, for example, a new energy vehicle, which can be a pure electric vehicle, a hybrid electric vehicle, or a range-extended electric vehicle, etc. The spacecraft includes airplanes, rockets, space shuttles, and spacecraft, etc. The electric toys include stationary or mobile electric toys, such as game consoles, electric car toys, electric ship toys, and electric airplane toys, etc. The power tools include metal cutting power tools, grinding power tools, assembly power tools, and railway power tools, such as electric drills, electric grinders, electric wrenches, electric screwdrivers, electric hammers, impact drills, concrete vibrators, and electric planers, etc. Since the electronic device includes the aforementioned negative-electrode all-solid-state battery, the advantages of including the aforementioned negative-electrode all-solid-state battery will not be elaborated further here.

[0084] In summary, this invention proposes a cathode-free all-solid-state battery and its applications. By forming a modification layer on the current collector, it achieves both high electronic conductivity and high ionic conductivity, forming an electron-ion dual-continuous network and significantly reducing interfacial charge transfer impedance. Furthermore, the modification layer induces uniform lithium nucleation. The high-entropy sulfide electrolyte, due to the severe lattice distortion and local disorder caused by the coexistence of multiple metal cations, forms numerous low-barrier lithium-ion migration paths, which can homogenize the lithium-ion flow and avoid excessively high local current densities. In the modification layer, the various cations mixed in the high-entropy sulfide electrolyte significantly reduce the system's Gibbs free energy, suppressing phase separation during high-temperature or electrochemical cycling. It acts as both an ionic conductor and a structural stabilizer, firmly bonding the lithiophilic layer to the carbon framework, preventing the modification layer from peeling off during cycling, and significantly improving the interfacial mechanical and electrochemical stability. By matching the modified negative electrode current collector with the solid electrolyte layer, the affinity of the negative electrode current collector for lithium, the ionic / electronic conductivity and interface stability are improved, and uniform nucleation and reversible deposition of lithium ions are achieved, thereby significantly improving the energy density, cycle life and safety of the negative electrode-free all-solid-state battery.

[0085] The above description is merely a preferred embodiment of this application and an explanation of the technical principles used. Those skilled in the art should understand that the scope of the invention involved in this application is not limited to the technical solutions formed by a specific combination of the above-mentioned technical features, but should also cover other technical solutions formed by any combination of the above-mentioned technical features or their equivalent features without departing from the inventive concept. For example, technical solutions formed by replacing the above-mentioned features with technical features with similar functions disclosed in this application (but not limited to) each other.

[0086] Apart from the technical features described in the specification, the other technical features are known to those skilled in the art. To highlight the innovative features of this invention, the other technical features will not be described in detail here.

Claims

1. A negative electrode-free all-solid-state battery, characterized in that, include: Positive electrode sheet; A negative electrode current collector, the negative electrode current collector comprising a current collector substrate and a modification layer disposed on at least one surface of the current collector substrate, the modification layer comprising a high-entropy sulfide electrolyte; as well as A solid electrolyte layer is disposed between the positive electrode and the negative electrode current collector. The modification layer is close to the solid electrolyte layer. The solid electrolyte layer includes the high-entropy sulfide electrolyte, the chemical formula of which is: Li 4±x-y A y (M1 a M2 b M3 c )S 4-δ X δ Where 0≤x≤1.5, 0≤y≤1.5, and y≤4±x; 0.4≤a≤0.8, 0.1≤b≤0.4, 0.1≤c≤0.3, a+b+c=1, 0≤δ≤1; A is selected from one or two of Na or K; M1 is selected from one or more of Ge, Sn, Si, P, As or B; M2 is selected from one or more of Sb, Nb, Ta, V, Mo, W, Ti, Zr, Hf or Re; M3 is selected from one or more of Al, Ga, In, Bi, Pb, Mg, Ca, Zn, Cd, Y, Sc, La, Ba, Sr, Ce or Sm; X is selected from one or more of O, Se or Te.

2. The all-solid-state battery without a negative electrode according to claim 1, characterized in that, The high-entropy sulfide electrolyte has a median particle size of 500 nm to 5 μm; and / or, the high-entropy sulfide electrolyte has an ionic conductivity of 1 × 10⁻⁶. -3 S / cm to 2×10 -2 S / cm.

3. The all-solid-state battery without a negative electrode according to claim 1, characterized in that, The median particle size of the high-entropy sulfide electrolyte is 1 μm to 3 μm.

4. The all-solid-state battery without a negative electrode according to claim 1, characterized in that, When the modification layer is a single layer, the modification layer includes a first modification layer, which includes a carbon material, the high-entropy sulfide electrolyte, a lithiophilic substance, and a binder. The mass ratio of the carbon material, the high-entropy sulfide electrolyte, and the lithiophilic substance is (50 to 90):(5 to 40):(1 to 15), and the binder accounts for 1 wt% to 5 wt% of the total mass of the carbon material, the high-entropy sulfide electrolyte, and the lithiophilic substance.

5. The all-solid-state battery without a negative electrode according to claim 4, characterized in that, The thickness of the first modified layer is from 0.1 μm to 10 μm, and the areal loading of the first modified layer is 0.1 mg / cm³. 2 Up to 2 mg / cm 2 .

6. The all-solid-state battery without a negative electrode according to claim 1, characterized in that, When the modification layer is multilayered, the modification layer includes a first modification layer and a second modification layer. The first modification layer is disposed on the current collector substrate, and the second modification layer is disposed on the surface of the first modification layer away from the current collector substrate.

7. The all-solid-state battery without a negative electrode according to claim 6, characterized in that, The first modification layer comprises a mixture of carbon material, high-entropy electrolyte and binder, wherein the mass ratio of the carbon material to the high-entropy electrolyte is (50 to 95):(5 to 50), and the binder accounts for 1 wt% to 5 wt% of the total mass of the carbon material and the high-entropy electrolyte; the second modification layer comprises a lithiophilic substance.

8. The all-solid-state battery without a negative electrode according to claim 6, characterized in that, The thickness of the first modified layer is from 0.1 μm to 10 μm, and the areal loading of the first modified layer is 0.1 mg / cm³. 2 Up to 2 mg / cm 2 The thickness of the second modification layer is 1 nm to 100 nm.

9. The all-solid-state battery without a negative electrode according to claim 4 or 7, characterized in that, The carbon material is selected from one or more of graphene, graphite, carbon nanotubes, hard carbon, soft carbon, carbon nanofibers, carbon black, or MXene. The lithiophilic substance is selected from one or more of Ag, Al, Au, Sn, Zn, Ca, In, Ca, Pb, Bi, Mg, or alloys formed by each of the above elements with lithium.

10. An electronic device, characterized in that, Including the all-solid-state battery without a negative electrode as described in any one of claims 1 to 9.

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