Negative electrode sheet and preparation method therefor and use thereof

Abstract

A negative electrode sheet and a preparation method therefor and a use thereof. The negative electrode sheet comprises: a current collector, wherein the current collector comprises a first side and a second side which are opposite to each other; and a first active material layer and a first artificial SEI layer, wherein the first active material layer and the first artificial SEI layer are sequentially arranged on the first side of the current collector in a direction moving away from the current collector, the first active material layer comprises metal lithium, and the first artificial SEI layer comprises a lithium compound and a lithium metal alloy. By using the negative electrode sheet, the problems of thickening of an SEI film, growth of lithium dendrites, dead lithium, piercing of a separator by the lithium dendrites and the like can be avoided, facilitating improving the cycle stability of a lithium metal battery.

Description

Negative electrode sheet and its preparation method and application

[0001] This application claims priority and benefits of patent application No. 202311572850.4 filed with the State Intellectual Property Office of China on November 22, 2023, and the entire text of which is incorporated herein by reference. Technical Field

[0002] The present invention belongs to the technical field of batteries, and in particular relates to a negative electrode plate and a preparation method and application thereof. Background Art

[0003] Compared with the theoretical specific capacity of 372mAh / g of graphite anode, metallic lithium has an ultra-high theoretical specific capacity of 3860mAh / g and the most negative standard reduction potential (-3.04V), as well as low density and small ionic radius. Using it as a negative electrode active material for batteries can further improve the energy density of batteries. However, whether metallic lithium anodes are used in solid or liquid systems, they face technical difficulties such as the high chemical reactivity of metallic lithium, the thickening of the SEI film caused by the infinite volume change rate, the growth of lithium dendrites, dead lithium, and lithium dendrites piercing the separator.

[0004] Summary of the Invention

[0005] The present invention aims to at least partially address one of the technical problems in the related art. To this end, one object of the present invention is to provide a negative electrode sheet, a method for preparing the same, and applications thereof. The negative electrode sheet can avoid problems such as SEI film thickening, lithium dendrite growth, dead lithium, and lithium dendrite piercing the separator, thereby improving the cycling stability of lithium metal batteries using the negative electrode sheet.

[0006] In a first aspect of the present invention, the present invention provides a negative electrode plate. According to an embodiment of the present invention, the negative electrode plate includes:

[0007] a current collector comprising opposing first and second sides;

[0008] A first active material layer and a first artificial SEI layer, wherein the first active material layer and the first artificial SEI layer are sequentially arranged on a first side of the current collector in a direction away from the current collector, the first active material layer includes metallic lithium, and the first artificial SEI layer includes a lithiation and a metallic lithium alloy.

[0009] According to the negative electrode plate of the above embodiment of the present invention, a first active material layer and a first artificial SEI layer are sequentially arranged on the first side of the current collector in a direction away from the current collector. The first active material layer includes metallic lithium, which can be used as a supplementary lithium source to improve the cycle life of the battery. The first artificial SEI layer includes a lithium compound and a metallic lithium alloy. On the one hand, the first artificial SEI layer can prevent the metallic lithium with high reactivity in the first active material layer from directly contacting the electrolyte or the electrolyte. On the other hand, the lithium compound in the first artificial SEI layer is conducive to the rapid migration of lithium ions, thereby effectively avoiding the growth of lithium dendrites caused by untimely deintercalation of lithium ions at the negative electrode, as well as the problems of continuous thickening of the SEI film, dead lithium, and lithium dendrites piercing the diaphragm caused by the infinite volume change rate. On the other hand, the metallic lithium alloy in the first artificial SEI layer can undergo an alloying reaction with metallic lithium during the charge and discharge process of the battery, which is conducive to the uniform deposition of metallic lithium, thereby effectively avoiding the growth of lithium dendrites caused by uneven deposition of metallic lithium, as well as the problems of continuous thickening of the SEI film, dead lithium, and lithium dendrites piercing the diaphragm caused by the infinite volume change rate. Therefore, the use of the negative electrode plate of the present invention can improve the interface problems of metallic lithium in secondary battery applications, avoid problems such as continuous thickening of the SEI film, continuous growth of lithium dendrites, dead lithium, and lithium dendrites piercing the diaphragm, thereby helping to improve the cycle stability of the lithium metal battery using the negative electrode plate.

[0010] In addition, the negative electrode sheet according to the above embodiment of the present invention may also have the following additional technical features:

[0011] In some embodiments of the present invention, the current collector is a composite current collector.

[0012] In some embodiments of the present invention, the current collector is a metal foil current collector, and the metal foil current collector includes at least one of copper, aluminum, zinc, nickel and chromium.

[0013] In some embodiments of the present invention, the current collector includes a base film, a first conductive layer disposed on one side of the base film, and a second conductive layer disposed on the other side opposite to the base film.

[0014] In some embodiments of the present invention, the negative electrode plate further includes a second active material layer, the second active material layer is disposed on the second side of the current collector, and the second active material layer includes a metallic lithium alloy.

[0015] In some embodiments of the present invention, the first active material layer is disposed on the first conductive layer, and the second active material layer is disposed on the second conductive layer.

[0016] In some embodiments of the present invention, the negative electrode sheet further includes a second artificial SEI layer, which is disposed on a side of the second active material layer away from the current collector, and the second artificial SEI layer includes a lithium compound.

[0017] In some embodiments of the present invention, the above-mentioned negative electrode sheet also includes a third active material layer and a third artificial SEI layer, and the third active material layer and the third artificial SEI layer are arranged in sequence on the second side of the current collector in a direction away from the current collector, the third active material layer includes metallic lithium, and the third artificial SEI layer includes lithium compound and metallic lithium alloy.

[0018] In some embodiments of the present invention, the first active material layer is disposed on the first conductive layer, and the third active material layer is disposed on the second conductive layer.

[0019] In some embodiments of the present invention, the above-mentioned negative electrode plate also includes a fourth active material layer and a fifth active material layer, and the fourth active material layer and the fifth active material layer are arranged in sequence on the second side of the current collector in a direction away from the current collector, the fourth active material layer includes metallic lithium, and the fifth active material layer includes a metallic lithium alloy.

[0020] In some embodiments of the present invention, the first active material layer is disposed on the first conductive layer, and the fourth active material layer is disposed on the second conductive layer.

[0021] In some embodiments of the present invention, the lithiation compound includes a compound of lithium and at least one of halogen, oxygen, nitrogen, sulfur, and phosphorus, thereby improving the cycle stability of the lithium metal battery.

[0022] In some embodiments of the present invention, the metal lithium alloy includes an alloy formed by metal lithium and at least one of gold, indium, magnesium, zinc, chromium, nickel, molybdenum, tungsten, vanadium, titanium, niobium, zirconium, cobalt, manganese, aluminum, copper, boron, silver, tin, silicon, carbon, phosphorus, and bismuth. This can improve the cycling stability of lithium metal batteries.

[0023] In some embodiments of the present invention, the metal lithium alloy in the first artificial SEI layer includes Li-M, wherein M includes at least one of gold, indium, magnesium, zinc, chromium, nickel, molybdenum, tungsten, vanadium, titanium, niobium, zirconium, cobalt, manganese, aluminum, copper, silver, tin and bismuth, and the molar ratio of the lithiation in the first artificial SEI layer to the Li-M is (0.1-10):1.

[0024] In a second aspect of the present invention, a method for preparing a negative electrode sheet is provided. According to an embodiment of the present invention, the method comprises:

[0025] providing a current collector comprising opposing first and second sides;

[0026] forming a first active material layer on a first side of the current collector, wherein the first active material layer includes metallic lithium;

[0027] A first artificial SEI layer is formed on the first active material layer at a side away from the current collector, wherein the first artificial SEI layer includes a lithiation and a metallic lithium alloy.

[0028] According to the method for preparing a negative electrode sheet of the above embodiment of the present invention, a current collector including a first side and a second side relative to each other is provided, and a first active material layer is formed on the first side of the current collector, and a first artificial SEI layer is formed on the first active material layer away from the current collector. The first active material layer includes metallic lithium, which can be used as a supplementary lithium source to improve the cycle life of the battery. The first artificial SEI layer includes a lithium compound and a metallic lithium alloy. On the one hand, the first artificial SEI layer can prevent the metallic lithium with high reactivity in the first active material layer from directly contacting the electrolyte or the electrolyte. On the other hand, the first artificial The lithium compounds in the SEI layer are conducive to the rapid migration of lithium ions, thereby effectively avoiding the growth of lithium dendrites caused by the untimely deintercalation of lithium ions at the negative electrode, as well as the problems of continuous thickening of the SEI film, dead lithium, and lithium dendrites piercing the diaphragm caused by the infinite volume change rate. On the other hand, the metal lithium alloy in the first artificial SEI layer can react with metal lithium to form an alloy during the battery charge and discharge process, which is conducive to the uniform deposition of metal lithium, thereby effectively avoiding the growth of lithium dendrites caused by uneven deposition of metal lithium, as well as the problems of continuous thickening of the SEI film, dead lithium, and lithium dendrites piercing the diaphragm caused by the infinite volume change rate. Therefore, the negative electrode sheet obtained by this method can improve the interface problems of metal lithium in secondary battery applications, avoid the problems of continuous thickening of the SEI film, continuous growth of lithium dendrites, dead lithium, and lithium dendrites piercing the diaphragm, thereby helping to improve the cycle stability of the lithium metal battery using the negative electrode sheet.

[0029] In addition, the method for preparing a negative electrode sheet according to the above embodiment of the present invention may also have the following additional technical features:

[0030] In some embodiments of the present invention, the above method also includes: forming a second active material layer on the second side of the current collector, the second active material layer comprising a metallic lithium alloy; and forming a second artificial SEI layer on a side of the second active material layer away from the current collector, the second artificial SEI layer comprising a lithium compound.

[0031] In some embodiments of the present invention, the above method also includes: forming a third active material layer on the second side of the current collector, wherein the third active material layer includes metallic lithium; forming a third artificial SEI layer on the side of the third active material layer away from the current collector, wherein the third artificial SEI layer includes a lithium compound and a metallic lithium alloy.

[0032] In a third aspect, the present invention provides a lithium metal battery. According to an embodiment of the present invention, the lithium metal battery includes the aforementioned negative electrode sheet or a negative electrode sheet obtained using the aforementioned method. As a result, the lithium metal battery exhibits high cycling stability.

[0033] In addition, the lithium metal battery according to the above embodiment of the present invention may also have the following additional technical features:

[0034] In some embodiments of the present invention, the lithium metal battery includes a liquid battery, a semi-solid battery and an all-solid battery.

[0035] In some embodiments of the present invention, the lithium metal battery includes a liquid battery and a semi-solid battery, and the lithium metal battery includes an electrolyte, and the electrolyte includes a lithium salt and a solvent.

[0036] In some embodiments of the present invention, the lithium salt includes at least one of lithium hexafluorophosphate, lithium perchlorate, lithium tetrafluoroborate, lithium hexafluoroarsenate, lithium trifluoromethanesulfonate, lithium bis(trifluoromethanesulfonyl)imide, lithium bis(fluorosulfonyl)imide, lithium trifluoromethanesulfonyl-perfluorobutylsulfonylimide, lithium fluorosulfonyl-perfluorobutylsulfonylimide, lithium bis(oxalatoborate) and tris(trifluoromethylsulfonyl)methyllithium.

[0037] In some embodiments of the present invention, the solvent includes at least one of ethylene carbonate, propylene carbonate, butylene carbonate, dimethyl carbonate, diethyl carbonate, ethyl methyl carbonate, γ-butyrolactone, tetrahydrofuran, 2-methyl-tetrahydrofuran, dimethoxydimethyl ether, 1,2-dimethoxyethane, 1,3-dioxolane and acetonitrile.

[0038] In some embodiments of the present invention, the electrolyte further includes additives, and the additives include at least one of film-forming additives, conductive additives, flame retardant additives, overcharge protection additives, water and HF content control additives, low-temperature additives and negative electrode stabilizers.

[0039] In some embodiments of the present invention, the lithium metal battery includes a semi-solid-state battery and an all-solid-state battery, and the lithium metal battery includes an electrolyte, and the electrolyte includes at least one of an inorganic solid electrolyte, a polymer solid electrolyte, and a composite solid electrolyte, and the inorganic solid electrolyte includes at least one of an oxide solid electrolyte, a sulfide solid electrolyte, and a halide solid electrolyte.

[0040] In a fourth aspect, the present invention provides a method for preparing a lithium metal battery. According to an embodiment of the present invention, the method includes: providing a negative electrode plate, the negative electrode plate including a current collector having a first side and a second side opposite to each other, the first side of the current collector being provided with a first active material layer, the first active material layer including metallic lithium, and a first metal compound layer being provided on a side of the first active material layer away from the current collector; assembling the negative electrode plate into a battery and charging the battery so that the first metal compound layer forms a first artificial SEI layer in situ during the battery charging process, the first artificial SEI layer including a lithium compound and a metallic lithium alloy, wherein the first metal compound layer includes a compound of at least one of halogen, oxygen, nitrogen, sulfur, and phosphorus and M, where M includes at least one of gold, indium, magnesium, zinc, chromium, nickel, molybdenum, tungsten, vanadium, titanium, niobium, zirconium, cobalt, manganese, aluminum, copper, silver, tin, and bismuth.

[0041] In a fifth aspect, the present invention provides another method for preparing a lithium metal battery. According to an embodiment of the present invention, the method includes: providing a negative electrode plate, the negative electrode plate including a current collector having a first side and a second side opposite to each other, the first side of the current collector being provided with a first active material layer, the first active material layer comprising metallic lithium, a first metal compound layer being provided on a side of the first active material layer away from the current collector, and a second active material layer being provided on a second side of the current collector, the second active material layer comprising a metallic lithium alloy; assembling the negative electrode plate into a battery and charging the battery so that the first metal compound layer forms a first artificial SEI layer in situ during the battery charging process, the first artificial SEI layer comprising a lithium compound and a metallic lithium alloy, wherein the first metal compound layer comprises a compound of at least one of halogen, oxygen, nitrogen, sulfur, and phosphorus and M, where M comprises at least one of gold, indium, magnesium, zinc, chromium, nickel, molybdenum, tungsten, vanadium, titanium, niobium, zirconium, cobalt, manganese, aluminum, copper, silver, tin, and bismuth.

[0042] In the sixth aspect of the present invention, the present invention provides another method for preparing a lithium metal battery. According to an embodiment of the present invention, the method includes: providing a negative electrode plate, the negative electrode plate including a current collector having a first side and a second side opposite to each other, the first side of the current collector being provided with a first active material layer, the first active material layer including metallic lithium, a first metal compound layer being provided on the first active material layer on a side away from the current collector, a second active material layer being provided on the second side of the current collector, the second active material layer including a metallic lithium alloy, a second artificial SEI layer being provided on the second active material layer on a side away from the current collector, the second artificial SEI layer including a lithium compound; assembling the negative electrode plates into a battery and charging the battery, so that the first metal compound layer forms a first artificial SEI layer in situ during the battery charging process, the first artificial SEI layer including a lithium compound and a metallic lithium alloy, wherein the first metal compound layer includes a compound of at least one of halogen, oxygen, nitrogen, sulfur and phosphorus and M, and M including at least one of gold, indium, magnesium, zinc, chromium, nickel, molybdenum, tungsten, vanadium, titanium, niobium, zirconium, cobalt, manganese, aluminum, copper, silver, tin and bismuth.

[0043] In the seventh aspect of the present invention, the present invention proposes another method for preparing a lithium metal battery. According to an embodiment of the present invention, the method includes: providing a negative electrode plate, the negative electrode plate including a current collector having a first side and a second side opposite to each other, the first side of the current collector is provided with a first active material layer, the first active material layer includes metallic lithium, a first metal compound layer is provided on the first active material layer away from the current collector, a third active material layer is provided on the second side of the current collector, the third active material layer includes metallic lithium, and a second metal compound layer is provided on the third active material layer away from the current collector; assembling the negative electrode plate into a battery and charging it so that the first active material layer is charged. The metal compound layer forms a first artificial SEI layer in situ during battery charging, so that the second metal compound layer forms a third artificial SEI layer in situ during battery charging, the first artificial SEI layer and the third artificial SEI layer independently include a lithium compound and a metal lithium alloy, wherein the first metal compound layer and the second metal compound layer independently include a compound of at least one of halogen, oxygen, nitrogen, sulfur and phosphorus and M, and M includes at least one of gold, indium, magnesium, zinc, chromium, nickel, molybdenum, tungsten, vanadium, titanium, niobium, zirconium, cobalt, manganese, aluminum, copper, silver, tin and bismuth.

[0044] In the eighth aspect of the present invention, the present invention provides another method for preparing a lithium metal battery. According to an embodiment of the present invention, the method includes: providing a negative electrode plate, the negative electrode plate including a current collector having a first side and a second side opposite to each other, a first active material layer provided on the first side of the current collector, the first active material layer including metallic lithium, a first metal compound layer provided on the side of the first active material layer away from the current collector, a fourth active material layer provided on the second side of the current collector, the fourth active material layer including metallic lithium, a fifth active material layer provided on the side of the fourth active material layer away from the current collector, the fifth active material layer including a metallic lithium alloy; assembling the negative electrode plate into a battery and charging the battery, so that the first metal compound layer forms a first artificial SEI layer in situ during the battery charging process, the first artificial SEI layer including a lithium compound and a metallic lithium alloy, wherein the first metal compound layer includes a compound of at least one of halogen, oxygen, nitrogen, sulfur and phosphorus and M, and M including at least one of gold, indium, magnesium, zinc, chromium, nickel, molybdenum, tungsten, vanadium, titanium, niobium, zirconium, cobalt, manganese, aluminum, copper, silver, tin and bismuth.

[0045] In its ninth aspect, the present invention provides an electrical device. According to an embodiment of the present invention, the electrical device comprises the aforementioned lithium metal battery or a lithium metal battery obtained by the aforementioned method for preparing a lithium metal battery. The electrical device and the aforementioned lithium metal battery or the aforementioned method for preparing a lithium metal battery have the same advantages over the prior art and are not further elaborated here.

[0046] Additional aspects and advantages of the present invention will be set forth in part in the description which follows and, in part, will be obvious from the description which follows, or may be learned by practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the following description of the embodiments with reference to the accompanying drawings, in which:

[0048] FIG1 is a schematic structural diagram of a negative electrode sheet according to an embodiment of the present invention;

[0049] FIG2 is a schematic structural diagram of a current collector according to an embodiment of the present invention;

[0050] FIG3 is a schematic structural diagram of a negative electrode sheet according to another embodiment of the present invention;

[0051] FIG4 is a schematic structural diagram of a negative electrode sheet according to another embodiment of the present invention;

[0052] FIG5 is a schematic structural diagram of a negative electrode sheet according to another embodiment of the present invention;

[0053] FIG6 is a schematic structural diagram of a negative electrode sheet according to another embodiment of the present invention;

[0054] FIG7 is a schematic structural diagram of a negative electrode sheet according to another embodiment of the present invention;

[0055] FIG8 is a schematic flow chart of a method for preparing a negative electrode sheet according to one embodiment of the present invention.

[0056] Reference numerals:

[0057] 1000-negative electrode; 10-current collector; 11-base film; 12-first conductive layer; 13-second conductive layer; 20-first active material layer; 30-first artificial SEI layer; 40-second active material layer; 50-second artificial SEI layer; 60-third active material layer; 70-third artificial SEI layer; 80-fourth active material layer; 90-fifth active material layer. DETAILED DESCRIPTION

[0058] The following describes embodiments of the present invention in detail, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present invention, and are not to be construed as limiting the present invention.

[0059] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like to indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0060] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of the technical features being referred to. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one such feature. In the description of the present invention, "plurality" means at least two, such as two, three, etc., unless otherwise specifically defined.

[0061] In a first aspect of the present invention, a negative electrode sheet is provided. According to an embodiment of the present invention, referring to FIG1 , the negative electrode sheet 1000 includes a current collector 10 , a first active material layer 20 , and a first artificial SEI (solid electrolyte membrane) layer 30 .

[0062] According to an embodiment of the present invention, the current collector 10 includes a first side and a second side that are opposite to each other. It should be noted that the specific type and thickness of the current collector 10 are not particularly limited, and those skilled in the art can select according to actual needs. For example, the current collector 10 can be a metal foil current collector or a composite current collector, and the thickness of the current collector 10 can be 1μm-10μm, such as 1μm, 2μm, 3μm, 4μm, 5μm, 6μm, 7μm, 8μm, 9μm, 10μm, etc. The metal foil current collector can include at least one of copper, aluminum, zinc, nickel, and chromium. Optionally, the metal foil current collector includes at least one of copper, nickel, a copper-nickel alloy, and a copper-zinc alloy. The thickness of the metal foil current collector is preferably 4μm-10μm.

[0063] According to a specific embodiment of the present invention, referring to FIG. 2 , the current collector 10 is a composite current collector, including a base film 11 , a first conductive layer 12 , and a second conductive layer 13 .

[0064] According to a specific embodiment of the present invention, the base film 11 can be made of a polymer. Since the base film 11 has a lower density than metal foils such as copper foil, the current collector 10 prepared using the base film 11 also has a lower density than current collectors made of metal foils such as copper foil, thereby improving the energy density of the battery.

[0065] According to a specific embodiment of the present invention, the base film 11 includes at least one of polyethylene (PE), polyethylene terephthalate (PET), polyimide (PI), polypropylene (PP), polyamide (PA), polyphenylene sulfide (PPS), and polyethylene naphthalate (PEN). Optionally, the base film 11 includes at least one of PET, PP, and PI; further optionally, the base film 11 includes PI and / or PPS. PI and PPS have flame retardant properties, which can reduce the risk of fire caused by lithium dendrites piercing the film and causing short circuits.

[0066] According to a specific embodiment of the present invention, the thickness of the base film 11 may be 1 μm-10 μm, for example, 1 μm, 2 μm, 3 μm, 4 μm, 5 μm, 6 μm, 7 μm, 8 μm, 9 μm, 10 μm, etc.

[0067] According to a specific embodiment of the present invention, referring to Figure 2, the first conductive layer 12 is arranged on one side of the base film 11, and the second conductive layer 13 is arranged on the other side opposite to the base film 11. By arranging the first conductive layer 12 on one side of the base film 11 and the second conductive layer 13 on the other side opposite to the base film 11, the conductivity of the current collector 10 can be improved.

[0068] According to a specific embodiment of the present invention, the first conductive layer 12 and the second conductive layer 13 independently include at least one of copper, aluminum, zinc, nickel and chromium, and the thickness of the first conductive layer 12 and the second conductive layer 13 can be independently 0.3μm-10μm, for example, 0.3μm, 0.5μm, 1μm, 3μm, 5μm, 7μm, 9μm, 10μm, etc.

[0069] According to a specific embodiment of the present invention, the first conductive layer 12 and the second conductive layer 13 can be independently prepared by physical vapor deposition (PVD), chemical vapor deposition (CVD) or water electroplating. For example, when copper is used as the first conductive layer 12 or the second conductive layer 13, it can be prepared on the base film 11 by a one-step method, a two-step method or a three-step method, wherein the one-step method includes a chemical deposition one-step method, a vacuum magnetron sputtering one-step method and a vacuum evaporation one-step method. The chemical deposition one-step method deposits the copper layer by chemical reaction, the vacuum magnetron sputtering one-step method deposits the copper layer by repeated magnetron sputtering, and the vacuum evaporation one-step method deposits the copper layer by repeated evaporation. The two-step method is to first use magnetron sputtering to prime, and then use water electroplating to thicken the copper layer. The three-step method is to first use magnetron sputtering to prime, then use vacuum evaporation, and finally use water electroplating to thicken the copper layer.

[0070] Therefore, the negative electrode plate 1000 of the present invention can improve the mechanical strength and mechanical properties of the negative electrode plate 1000 by adopting a composite current collector. On the other hand, the composite current collector has the characteristics of low manufacturing cost, high safety and good compatibility. On the other hand, the density of the composite current collector is lower than that of metal foil current collectors such as copper foil (weight reduction of more than 60%), which can improve the energy density of the battery.

[0071] According to an embodiment of the present invention, referring to FIG1 , a first active material layer 20 and a first artificial SEI layer 30 are sequentially arranged on a first side of the current collector 10 in a direction away from the current collector 10, the first active material layer 20 includes metallic lithium, and the first artificial SEI layer 30 includes a lithium compound and a metallic lithium alloy. The inventors have discovered that by sequentially arranging the first active material layer 20 and the first artificial SEI layer 30 on the first side of the current collector 10 in a direction away from the current collector 10, the first active material layer 20 includes metallic lithium, which can be used as a supplementary lithium source to improve the cycle life of the battery, and the first artificial SEI layer 30 includes a lithium compound and a metallic lithium alloy. On the one hand, the first artificial SEI layer 30 can prevent the metallic lithium with high reactivity in the first active material layer 20 from directly contacting the electrolyte or the electrolyte. On the other hand, the lithium compound in the first artificial SEI layer 30 is beneficial to The rapid migration of lithium ions effectively avoids the problems of lithium dendrite growth caused by the untimely deintercalation of lithium ions at the negative electrode, as well as the problems of continuous thickening of the SEI film, dead lithium, and lithium dendrites piercing the diaphragm caused by the infinite volume change rate. On the other hand, the metal lithium alloy in the first artificial SEI layer 30 can react with metal lithium to form an alloy during the battery charge and discharge process, which is beneficial to the uniform deposition of metal lithium, thereby effectively avoiding the problems of lithium dendrite growth caused by uneven deposition of metal lithium, as well as the problems of continuous thickening of the SEI film, dead lithium, and lithium dendrites piercing the diaphragm caused by the infinite volume change rate. Therefore, the use of the negative electrode plate 1000 of the present invention can improve the interface problems of metal lithium in secondary battery applications, avoid the problems of continuous thickening of the SEI film, continuous growth of lithium dendrites, dead lithium, and lithium dendrites piercing the diaphragm, thereby helping to improve the cycle stability of the lithium metal battery using the negative electrode plate 1000.

[0072] According to a specific embodiment of the present invention, referring to FIG. 3 , the first active material layer 20 is disposed on the first conductive layer 12 .

[0073] According to a specific embodiment of the present invention, the thickness of the first active material layer 20 can be 0.1μm-100μm, for example, it can be 0.1μm, 0.5μm, 1μm, 5μm, 10μm, 30μm, 50μm, 70μm, 90μm, 100μm, etc., and the thickness of the first artificial SEI layer 30 can be 0.1μm-1μm, for example, it can be 0.1μm, 0.2μm, 0.3μm, 0.4μm, 0.5μm, 0.6μm, 0.7μm, 0.8μm, 0.9μm, 1μm, etc.

[0074] According to a specific embodiment of the present invention, the lithium compound includes a compound of lithium and at least one of halogen (such as fluorine), oxygen, nitrogen, sulfur, and phosphorus. Optionally, the lithium compound includes at least one of lithium fluoride (LiF), lithium oxide (Li2O), lithium sulfide (Li2S), lithium nitride (Li3N), lithium phosphide (Li3P), and lithium phosphorus oxynitride (LiPON).

[0075] According to a specific embodiment of the present invention, the metallic lithium alloy includes an alloy formed by metallic lithium and at least one of gold, indium, magnesium, zinc, chromium, nickel, molybdenum, tungsten, vanadium, titanium, niobium, zirconium, cobalt, manganese, aluminum, copper, boron, silver, tin, silicon, carbon, phosphorus, and bismuth. Specifically, the content of lithium in the metallic lithium alloy may be 0.1 atm% to 99.9 atm%, for example, 0.1 atm%, 1 atm%, 2 atm%, 5 atm%, 15 atm%, 35 atm%, 55 atm%, 75 atm%, 95 atm%, 99.9 atm%, etc.

[0076] According to a specific embodiment of the present invention, the metal lithium alloy in the first artificial SEI layer 30 includes Li-M, wherein M includes at least one of gold, indium, magnesium, zinc, chromium, nickel, molybdenum, tungsten, vanadium, titanium, niobium, zirconium, cobalt, manganese, aluminum, copper, silver, tin and bismuth, and the molar ratio of the lithium compound to Li-M in the first artificial SEI layer 30 is (0.1-10):1, for example, it can be 0.1:1, 0.5:1, 1:1, 2:1, 3:1, 4:1, 5:1, 6:1, 8:1, 10:1, etc.

[0077] According to a specific embodiment of the present invention, referring to FIG4 , the negative electrode sheet 1000 further includes a second active material layer 40, which is disposed on the second side of the current collector 10, and the second active material layer 40 includes a metal lithium alloy. By disposing the second active material layer 40 including a metal lithium alloy on the second side of the current collector 10, an alloying reaction can be generated between the metal lithium and the metal lithium alloy in the second active material layer 40 during the charge and discharge process of the battery, which is further beneficial to avoid the uneven deposition of metal lithium causing the growth of lithium dendrites, as well as the problems such as the continuous thickening of the SEI film, dead lithium, and lithium dendrites piercing the diaphragm caused by the infinite volume change rate, thereby further improving the cycle stability of the lithium metal battery. Specifically, the second active material layer 40 can be disposed on the second conductive layer 13, and the thickness of the second active material layer 40 can be 0.1 μm-100 μm, for example, 0.1 μm, 0.5 μm, 1 μm, 5 μm, 10 μm, 30 μm, 50 μm, 70 μm, 90 μm, 100 μm, etc.

[0078] According to a specific embodiment of the present invention, referring to FIG5 , the negative electrode sheet 1000 further includes a second artificial SEI layer 50. The second artificial SEI layer 50 is disposed on a side of the second active material layer 40 away from the current collector 10. The second artificial SEI layer 50 includes a lithium compound. Providing the second artificial SEI layer 50 including a lithium compound on a side of the second active material layer 40 away from the current collector 10 further facilitates the rapid migration of lithium ions, thereby effectively preventing the growth of lithium dendrites caused by untimely lithium ion deintercalation at the negative electrode, as well as problems such as continuous thickening of the SEI film, dead lithium, and lithium dendrites piercing the separator caused by an infinite volume change rate, thereby further improving the cycling stability of the lithium metal battery. Specifically, the thickness of the second artificial SEI layer 50 can be 0.1 μm to 1 μm, for example, 0.1 μm, 0.2 μm, 0.3 μm, 0.4 μm, 0.5 μm, 0.6 μm, 0.7 μm, 0.8 μm, 0.9 μm, 1 μm, etc.

[0079] According to a specific embodiment of the present invention, referring to Figure 6, the negative electrode sheet 1000 also includes a third active material layer 60 and a third artificial SEI layer 70. The third active material layer 60 and the third artificial SEI layer 70 are sequentially arranged on the second side of the current collector 10 in a direction away from the current collector 10. The third active material layer 60 includes metallic lithium, and the third artificial SEI layer 70 includes a lithiation and a metallic lithium alloy. By sequentially arranging a third active material layer 60 and a third artificial SEI layer 70 on the second side of the current collector 10 in a direction away from the current collector 10, the third active material layer 60 includes metallic lithium, which can be used as a supplementary lithium source to improve the cycle life of the battery. The third artificial SEI layer 70 includes a lithium compound and a metallic lithium alloy. On the one hand, the third artificial SEI layer 70 can prevent the metallic lithium in the third active material layer 60 from directly contacting the electrolyte or the electrolyte. On the other hand, the lithium compound in the third artificial SEI layer 70 can further facilitate the rapid migration of lithium ions, thereby effectively avoiding the problems of lithium dendrite growth caused by untimely lithium ion deintercalation at the negative electrode, as well as the problems of continuous thickening of the SEI film, dead lithium, and lithium dendrites piercing the diaphragm caused by the infinite volume change rate. On the other hand, the metallic lithium alloy in the third artificial SEI layer 70 can undergo an alloying reaction with metallic lithium during the charge and discharge process of the battery, which is further conducive to avoiding the problems of lithium dendrite growth caused by uneven deposition of metallic lithium, as well as the problems of continuous thickening of the SEI film, dead lithium, and lithium dendrites piercing the diaphragm caused by the infinite volume change rate, thereby further facilitating the improvement of the cycle stability of the lithium metal battery. Specifically, the third active material layer 60 can be arranged on the second conductive layer 13, and the thickness of the third active material layer 60 can be 0.1μm-100μm, for example, it can be 0.1μm, 0.5μm, 1μm, 5μm, 10μm, 30μm, 50μm, 70μm, 90μm, 100μm, etc. The thickness of the third artificial SEI layer 70 can be 0.1μm-1μm, for example, it can be 0.1μm, 0.2μm, 0.3μm, 0.4μm, 0.5μm, 0.6μm, 0.7μm, 0.8μm, 0.9μm, 1μm, etc.

[0080] According to a specific embodiment of the present invention, the metal lithium alloy in the third artificial SEI layer 70 includes Li-M, wherein M includes at least one of gold, indium, magnesium, zinc, chromium, nickel, molybdenum, tungsten, vanadium, titanium, niobium, zirconium, cobalt, manganese, aluminum, copper, silver, tin and bismuth, and the molar ratio of the lithium compound to Li-M in the third artificial SEI layer 70 is (0.1-10):1, for example, it can be 0.1:1, 0.5:1, 1:1, 2:1, 3:1, 4:1, 5:1, 6:1, 8:1, 10:1, etc.

[0081] According to a specific embodiment of the present invention, referring to Figure 7, the negative electrode sheet 1000 also includes a fourth active material layer 80 and a fifth active material layer 90. The fourth active material layer 80 and the fifth active material layer 90 are sequentially arranged on the second side of the current collector 10 in a direction away from the current collector 10. The fourth active material layer 80 includes metallic lithium, and the fifth active material layer 90 includes a metallic lithium alloy. By sequentially arranging the fourth active material layer 80 and the fifth active material layer 90 on the second side of the current collector 10 in a direction away from the current collector 10, the fourth active material layer 80 includes metallic lithium, which can be used as a supplementary lithium source to improve the cycle life of the battery, and the fifth active material layer 90 includes a metallic lithium alloy. On the one hand, it can avoid direct contact between the metallic lithium in the fourth active material layer 80 and the electrolyte or electrolyte, and on the other hand, it can enable the metallic lithium and the metallic lithium alloy in the fifth active material layer 90 to undergo alloying reaction during the battery charging and discharging process, effectively avoiding the uneven deposition of metallic lithium causing the growth of lithium dendrites, as well as the problems of continuous thickening of the SEI film, dead lithium, and lithium dendrites piercing the diaphragm caused by the infinite volume change rate, thereby helping to improve the cycle stability of the lithium metal battery using the negative electrode sheet 1000. Specifically, the fourth active material layer 80 can be arranged on the second conductive layer 13, and the thickness of the fourth active material layer 80 and the fifth active material layer 90 can be independently 0.1μm-100μm, for example, 0.1μm, 0.5μm, 1μm, 5μm, 10μm, 30μm, 50μm, 70μm, 90μm, 100μm, etc.

[0082] According to a specific embodiment of the present invention, the first active material layer 20, the second active material layer 40, the third active material layer 60, the fourth active material layer 80 and the fifth active material layer 90 can be independently prepared by rolling (i.e., rolling the metal strip as the active material layer to the surface of the current collector or other active material layer) or physical vapor deposition (PVD, such as magnetron sputtering, vacuum evaporation, etc.), preferably the physical vapor deposition method, thereby helping to reduce the thickness of the active material layer and achieve uniform deposition, thereby reducing the amount of active material used and reducing costs. Optionally, the metal lithium alloy Li-M can be magnetron sputtered to sputter the metal M onto the surface of the metal Li layer to form an active material layer including a metal lithium alloy. Alternatively, the metal lithium alloy Li-M can be deposited by vacuum evaporation, that is, metal Li and metal M in the shape of strips, blocks, etc. are placed in containers (such as evaporation boats, crucibles, etc.), respectively. Considering the melting points of metal Li and metal M, different evaporation methods (such as resistance heating, electron beam evaporation, high-frequency heating, laser heating, etc.) and different evaporation temperatures can be used to control the composition and deposition rate of the metal lithium alloy under the premise of setting a reasonable evaporation chamber pressure and substrate temperature.

[0083] According to a specific embodiment of the present invention, the second artificial SEI layer 50 can be formed directly by physical vapor deposition (PVD), chemical vapor deposition (CVD), atomic layer deposition (ALD), or other methods to form a layer of a compound formed by metallic lithium and halogen, oxygen, nitrogen, sulfur, phosphorus, or the like, such as lithium fluoride, lithium oxide, lithium nitride, lithium sulfide, or lithium phosphide. Furthermore, lithium phosphate (Li3PO4) can be magnetron sputtered in a nitrogen atmosphere to form a lithium phosphorus oxynitride (LiPON). Furthermore, a compound formed by lithium and halogen, oxygen, nitrogen, sulfur, or phosphorus, such as at least one of lithium fluoride (LiF), lithium oxide (Li2O), lithium sulfide (Li2S), lithium nitride (Li3N), lithium phosphide (Li3P), and lithium phosphorus oxynitride (LiPON), can also be directly applied to the negative electrode surface using dry coating or wet coating.

[0084] According to a specific embodiment of the present invention, the first artificial SEI layer 30 and the third artificial SEI layer 70 can be independently formed using an in-situ method. Specifically, a metal compound layer comprising a compound of at least one of halogen, oxygen, nitrogen, sulfur, and phosphorus with M is independently formed on the first active material layer 20 and the third active material layer 60 comprising metallic lithium. During battery charging, the metal compound layer reacts with lithium atoms from the positive electrode to form a lithiate and a metallic lithium alloy. This effectively avoids the process complexity associated with multi-layer deposition.

[0085] Therefore, the use of the negative electrode plate 1000 of the present invention can improve the interface problems of metallic lithium in secondary battery applications, avoid problems such as continuous thickening of the SEI film, continuous growth of lithium dendrites, dead lithium, and lithium dendrites piercing the diaphragm, thereby helping to improve the cycle stability of lithium metal batteries.

[0086] In a second aspect of the present invention, referring to FIG8 , the present invention provides a method for preparing a negative electrode sheet. Referring to FIG8 , according to an embodiment of the present invention, the method includes:

[0087] S100: Providing a current collector, the current collector including a first side and a second side opposite to each other

[0088] In this step, a current collector 10 is provided. The current collector 10 includes a first side and a second side that are opposite to each other. It should be noted that the specific method for preparing the current collector 10 is not particularly limited and may, for example, include forming a first conductive layer 12 on one side of a base film 11 and forming a second conductive layer 13 on a side of the base film 11 that is away from the first conductive layer 12. By forming the first conductive layer 12 on one side of the base film 11 and the second conductive layer 13 on the opposite side of the base film 11, the conductivity of the current collector 10 can be improved.

[0089] S200: forming a first active material layer on the first side of the current collector, the first active material layer including metallic lithium

[0090] In this step, a first active material layer 20 comprising metallic lithium is formed on the first side of the current collector 10. The inventors have discovered that forming the first active material layer 20 comprising metallic lithium on the first side of the current collector 10 can serve as a supplemental lithium source, thereby improving the cycle life of the battery. Specifically, the first active material layer 20 can be formed on the first conductive layer 12.

[0091] S300: forming a first artificial SEI layer on the first active material layer away from the current collector, the first artificial SEI layer including a lithium compound and a metallic lithium alloy

[0092] In this step, a first artificial SEI layer 30 is formed on the first active material layer 20 at a side away from the current collector 10 . The first artificial SEI layer 30 includes a lithiation and a metallic lithium alloy. The inventors discovered that by forming a first artificial SEI layer 30 including a lithium compound and a metallic lithium alloy on the side of the first active material layer 20 away from the current collector 10, on the one hand, the first artificial SEI layer 30 can prevent the metallic lithium with high reactivity in the first active material layer 20 from directly contacting the electrolyte or the electrolyte. On the other hand, the lithium compound in the first artificial SEI layer 30 is conducive to the rapid migration of lithium ions, thereby effectively avoiding the growth of lithium dendrites caused by the untimely deintercalation of lithium ions at the negative electrode, as well as the problems of continuous thickening of the SEI film, dead lithium, and lithium dendrites piercing the diaphragm caused by the infinite volume change rate. On the other hand, the metallic lithium alloy in the first artificial SEI layer 30 can undergo an alloying reaction with metallic lithium during the battery charging and discharging process, which is conducive to the uniform deposition of metallic lithium, thereby effectively avoiding the growth of lithium dendrites caused by the uneven deposition of metallic lithium, as well as the problems of continuous thickening of the SEI film, dead lithium, and lithium dendrites piercing the diaphragm caused by the infinite volume change rate.

[0093] Therefore, the negative electrode plate obtained by the method for preparing the negative electrode plate of the present invention can improve the interface problem of metallic lithium in the application of secondary batteries, avoid the problems of continuous thickening of SEI film, continuous growth of lithium dendrites, dead lithium, lithium dendrites piercing the diaphragm, etc., thereby helping to improve the cycle stability of lithium metal batteries.

[0094] According to a specific embodiment of the present invention, the method further includes: forming a second active material layer 40 on the second side of the current collector 10, the second active material layer 40 comprising a metallic lithium alloy; and forming a second artificial SEI layer 50 on the side of the second active material layer 40 away from the current collector, the second artificial SEI layer 50 comprising a lithium compound. This improves the cycling stability of lithium metal batteries. Forming the second active material layer 40 comprising metallic lithium on the second side of the current collector 10 serves as a supplemental lithium source, improving the battery's cycle life. Forming the second artificial SEI layer 50 comprising a lithium compound on the side of the second active material layer 40 away from the current collector 10 prevents direct contact between the metallic lithium in the second active material layer 40 and the electrolyte or electrolyte, while also facilitating the rapid migration of lithium ions. This effectively prevents the growth of lithium dendrites caused by untimely lithium ion deintercalation at the negative electrode, as well as problems such as continuous SEI film thickening, dead lithium, and lithium dendrites piercing the separator caused by an infinite volume change rate, further improving the cycling stability of lithium metal batteries.

[0095] According to a specific embodiment of the present invention, the above method also includes: forming a third active material layer 60 on the second side of the current collector 10, the third active material layer 60 includes metallic lithium; forming a third artificial SEI layer 70 on the side of the third active material layer 60 away from the current collector 10, the third artificial SEI layer 70 includes a lithium compound and a metallic lithium alloy. The inventors discovered that by forming a third active material layer 60 including metallic lithium on the second side of the current collector 10, it can be used as a supplementary lithium source to improve the cycle life of the battery. A third artificial SEI layer 70 including a lithium compound and a metallic lithium alloy is formed on the side of the third active material layer 60 away from the current collector 10. On the one hand, the third artificial SEI layer 70 can prevent the metallic lithium in the third active material layer 60 from directly contacting the electrolyte or electrolyte. On the other hand, the lithium compound in the third artificial SEI layer 70 is conducive to the rapid migration of lithium ions, thereby effectively avoiding the growth of lithium dendrites caused by the untimely deintercalation of lithium ions at the negative electrode, as well as the problems of continuous thickening of the SEI film, dead lithium, and lithium dendrites piercing the diaphragm caused by the infinite volume change rate. On the other hand, the metallic lithium alloy in the third artificial SEI layer 70 can undergo an alloying reaction with metallic lithium during the battery charging and discharging process, effectively avoiding the growth of lithium dendrites caused by uneven deposition of metallic lithium, as well as the problems of continuous thickening of the SEI film, dead lithium, and lithium dendrites piercing the diaphragm caused by the infinite volume change rate.

[0096] It should be noted that the materials and thicknesses of the base film 11, the first conductive layer 12, the second conductive layer 13, the first active material layer 20, the second active material layer 40, the third active material layer 60, the fourth active material layer 80, the fifth active material layer 90, the first artificial SEI layer 30, the second artificial SEI layer 50 and the third artificial SEI layer 70, as well as the preparation methods of the first conductive layer 12, the second conductive layer 13, the first active material layer 20, the second active material layer 40, the third active material layer 60, the fourth active material layer 80, the fifth active material layer 90, the first artificial SEI layer 30, the second artificial SEI layer 50 and the third artificial SEI layer 70 have been described in detail above and will not be repeated here.

[0097] In its third aspect, the present invention provides a lithium metal battery. According to an embodiment of the present invention, the lithium metal battery comprises the aforementioned negative electrode sheet or a negative electrode sheet obtained using the aforementioned method. As a result, the lithium metal battery exhibits high cycling stability. It should be noted that the features and advantages described above for the negative electrode sheet also apply to this lithium metal battery and will not be further elaborated here.

[0098] According to a specific embodiment of the present invention, the above-mentioned lithium metal battery includes a liquid battery, a semi-solid battery and an all-solid battery.

[0099] According to a specific embodiment of the present invention, the lithium metal battery includes a liquid battery and a semi-solid battery, and the lithium metal battery includes an electrolyte.

[0100] According to a specific embodiment of the present invention, the above-mentioned lithium metal battery includes the above-mentioned negative electrode plate or the negative electrode plate obtained by the above-mentioned method for preparing the negative electrode plate, a positive electrode plate, a separator and an electrolyte, which are composed of a liquid laminated soft-pack battery, a liquid wound battery or a liquid cylindrical battery.

[0101] According to a specific embodiment of the present invention, the above-mentioned lithium metal battery also includes the above-mentioned negative electrode sheet or the negative electrode sheet obtained by the above-mentioned method for preparing the negative electrode sheet, a semi-solid laminated soft-pack battery, a semi-solid wound battery or a semi-solid cylindrical battery composed of a positive electrode sheet and a gel electrolyte.

[0102] According to a specific embodiment of the present invention, the above-mentioned lithium metal battery also includes a semi-solid laminated soft-pack battery, a semi-solid wound battery or a semi-solid cylindrical battery consisting of the above-mentioned negative electrode sheet or the negative electrode sheet obtained by the above-mentioned method for preparing the negative electrode sheet, a positive electrode sheet, a gel electrolyte and an optional 0.5wt%-50wt% additive.

[0103] According to a specific embodiment of the present invention, the above-mentioned electrolyte mainly includes a lithium salt, a solvent and an optional additive. Specifically, the solvent may include carbonates (such as ethylene carbonate (EC), propylene carbonate (PC), butylene carbonate (BC), dimethyl carbonate (DMC), diethyl carbonate (DEC), ethyl methyl carbonate (EMC), γ-butyrolactone (BL)), ethers (such as tetrahydrofuran (THF), 2-methyl-tetrahydrofuran (2-Me-THF), dimethoxydimethyl ether (DMM), 1,2-dimethoxyethane (DME)), 1,3-dioxolane (DOL), nitriles (such as acetonitrile (AN)), etc.; lithium salts may include lithium hexafluorophosphate (LiPF6), lithium perchlorate (LiClO4), lithium tetrafluoroborate (LiBF4), lithium hexafluoroarsenate (LiAsF6), other organic lithium salts (such as lithium trifluoromethylsulfonate (LiCF3SO), difluoromethanesulfonate (DMF ... Lithium trifluoromethanesulfonyl imide (LiTFSI), lithium bisfluorosulfonyl imide (LiFSI), lithium trifluoromethanesulfonyl-perfluorobutylsulfonyl imide (LiTNFSI), lithium fluorosulfonyl-perfluorobutylsulfonyl imide (LiFNFSI), lithium bisoxalatoborate (LiBOB), tris(trifluoromethylsulfonyl)methyllithium (LiC(SO2CF3)3), etc.); additives may include film-forming additives, conductive additives, flame retardant additives, overcharge protection additives, water and HF content control additives (i.e., additives for controlling the water and HF content in the electrolyte), low-temperature additives (i.e., general additives for improving low-temperature performance), and may also include negative electrode stabilizers, i.e., additives for improving the interface stability of the metallic lithium negative electrode (e.g., fluoroethylene carbonate (FEC), lithium nitrate (LiNO3), etc.).

[0104] According to a specific embodiment of the present invention, the above-mentioned lithium metal battery includes a semi-solid-state battery and an all-solid-state battery. The lithium metal battery includes an electrolyte, and the electrolyte includes at least one of an inorganic solid electrolyte, a polymer solid electrolyte and a composite solid electrolyte. The inorganic solid electrolyte includes an oxide solid electrolyte or a sulfide solid electrolyte.

[0105] According to a specific embodiment of the present invention, the above-mentioned lithium metal battery also includes the above-mentioned negative electrode sheet or the negative electrode sheet obtained by the above-mentioned method for preparing the negative electrode sheet, a solid-state laminated soft-pack battery, a solid-state wound battery or a solid-state cylindrical battery composed of a positive electrode sheet and a solid-state electrolyte.

[0106] According to a specific embodiment of the present invention, the above-mentioned positive electrode plate can be a positive electrode plate using a metal foil current collector, or a positive electrode plate using a composite current collector, wherein the positive electrode active material includes lithium nickel cobalt manganese oxide (LiN x M y C z O2, x+y+z=1), lithium manganese iron phosphate (LiFe a Mnb PO4, a+b=1), at least one of lithium iron phosphate, lithium manganate, lithium cobaltate, lithium nickelate, lithium-rich manganese-based positive electrode material, lithium nickel manganate (LMNO) and lithium vanadium phosphate (Li3V2(PO4)3, LiVOPO4).

[0107] According to a specific embodiment of the present invention, the separator includes polypropylene (PP) and / or polyethylene (PE).

[0108] According to a specific embodiment of the present invention, the above-mentioned solid electrolyte includes an inorganic solid electrolyte (such as an oxide solid electrolyte, a sulfide solid electrolyte, a halide solid electrolyte), a polymer solid electrolyte and a composite solid electrolyte (such as a composite solid electrolyte based on a polymer matrix and an inorganic filler). Specifically, the oxide solid electrolyte may include a NASICON type (stable structure, such as LATP (Li 1.3 Al 0.3 Ti 1.7 (PO4)3)、LAGP(Li 1.5 Al 0.5 Ge 1.5 P3O 12 ), perovskite type, garnet type (highest conductivity, 10 -3 S / cm, which has good stability to metallic lithium, such as lithium lanthanum zirconium oxide (LLZO); sulfide solid electrolytes can include binary compounds (such as Li2S-SiS2 and Li2S-P2S5, Li2S-GeS2, etc.), ternary compounds (such as Li2S-MS2-P2S5 (M=Si, Ge, Sn, Al, etc.), and Li6PS5X (X=F, Cl, Br, I); halide solid electrolytes can include Li a MX4 type (X represents halogen elements, such as Li2MnCl4, Li2ZnCl4, etc. formed by divalent metal ions, and halide electrolytes formed by trivalent and other valence metal ions M, such as LiYbF4, LiAlF4), Li a MX6 (such as Li3YCl6 (LYC) and Li3BrCl6 (LYB)) and Li aMX8 type (such as Li6CoCl8). The polymer solid electrolyte can include polyethylene oxide (PEO), polycarbonate, polytrimethylene carbonate (PTMC), polymethyl methacrylate (PMMA), polyacrylonitrile (PAN), polyvinylidene fluoride (PVDF), polyvinylidene fluoride-hexafluoroethylene copolymer, lithium polyacrylate (PAL) and other polymer matrices, LATP, lithium lanthanum zirconium oxide (LLZO), aluminum oxide (Al2O3), metal organic frameworks (MOFs) and other inorganic fillers and LiAsF6, lithium hexafluorophosphate (LiPF6), lithium perchlorate (LiClO4), lithium bis(trifluoromethanesulfonyl)imide (LiTFSI), lithium bis(fluorosulfonyl)imide (LiFSI), lithium tetrafluoroborate (LiBF4) and other lithium salts. Specifically, the gel electrolyte can include at least one of the above solid electrolytes and at least one of the above electrolytes.

[0109] In a fourth aspect, the present invention provides a method for preparing a lithium metal battery. According to an embodiment of the present invention, the method includes: providing a negative electrode plate, the negative electrode plate including a current collector having a first side and a second side opposite to each other, the first side of the current collector being provided with a first active material layer, the first active material layer including metallic lithium, and a first metal compound layer being provided on a side of the first active material layer away from the current collector; assembling the negative electrode plates into a battery and charging the battery so that the first metal compound layer forms a first artificial SEI layer in situ during the battery charging process, the first artificial SEI layer including a lithium compound and a metallic lithium alloy, wherein the first metal compound layer includes a compound of at least one of halogen, oxygen, nitrogen, sulfur, and phosphorus and M, where M includes at least one of gold, indium, magnesium, zinc, chromium, nickel, molybdenum, tungsten, vanadium, titanium, niobium, zirconium, cobalt, manganese, aluminum, copper, silver, tin, and bismuth.

[0110] In a fifth aspect, the present invention provides another method for preparing a lithium metal battery. According to an embodiment of the present invention, the method includes: providing a negative electrode plate, the negative electrode plate including a current collector having a first side and a second side opposite to each other, the first side of the current collector being provided with a first active material layer, the first active material layer comprising metallic lithium, a first metal compound layer being provided on the first active material layer on a side away from the current collector, and a second active material layer being provided on the second side of the current collector, the second active material layer comprising a metallic lithium alloy; assembling the negative electrode plates into a battery and charging the battery so that the first metal compound layer forms a first artificial SEI layer in situ during the battery charging process, the first artificial SEI layer comprising a lithium compound and a metallic lithium alloy, wherein the first metal compound layer comprises a compound of at least one of halogen, oxygen, nitrogen, sulfur, and phosphorus and M, wherein M comprises at least one of gold, indium, magnesium, zinc, chromium, nickel, molybdenum, tungsten, vanadium, titanium, niobium, zirconium, cobalt, manganese, aluminum, copper, silver, tin, and bismuth.

[0111] In a sixth aspect, the present invention provides another method for preparing a lithium metal battery. According to an embodiment of the present invention, the method includes: providing a negative electrode plate, the negative electrode plate including a current collector having opposing first and second sides, the first active material layer disposed on the first side of the current collector, the first active material layer comprising metallic lithium, a first metal compound layer disposed on the first active material layer on a side away from the current collector, a second active material layer disposed on the second side of the current collector, the second active material layer comprising a metallic lithium alloy, and a second artificial SEI layer disposed on the second active material layer on a side away from the current collector, the second artificial SEI layer comprising a lithium compound; assembling the negative electrode plate into a battery and charging the battery, so that the first metal compound layer forms a first artificial SEI layer in situ during the battery charging process, the first artificial SEI layer comprising a lithium compound and a metallic lithium alloy, wherein the first metal compound layer comprises a compound of at least one of halogen, oxygen, nitrogen, sulfur, and phosphorus and M, wherein M comprises at least one of gold, indium, magnesium, zinc, chromium, nickel, molybdenum, tungsten, vanadium, titanium, niobium, zirconium, cobalt, manganese, aluminum, copper, silver, tin, and bismuth.

[0112] In the seventh aspect of the present invention, the present invention proposes another method for preparing a lithium metal battery. According to an embodiment of the present invention, the method includes: providing a negative electrode plate, the negative electrode plate including a current collector having a first side and a second side opposite to each other, the first side of the current collector is provided with a first active material layer, the first active material layer includes metallic lithium, a first metal compound layer is provided on the first active material layer away from the current collector, a third active material layer is provided on the second side of the current collector, the third active material layer includes metallic lithium, and a second metal compound layer is provided on the third active material layer away from the current collector; assembling the negative electrode plates into a battery and charging the battery so that the first metal compound layer is A first artificial SEI layer is formed in situ during battery charging, and the second metal compound layer forms a third artificial SEI layer in situ during battery charging. The first artificial SEI layer and the third artificial SEI layer independently include a lithium compound and a metal lithium alloy, respectively. The first metal compound layer and the second metal compound layer independently include a compound of at least one of halogen, oxygen, nitrogen, sulfur and phosphorus and M, and M includes at least one of gold, indium, magnesium, zinc, chromium, nickel, molybdenum, tungsten, vanadium, titanium, niobium, zirconium, cobalt, manganese, aluminum, copper, silver, tin and bismuth.

[0113] In an eighth aspect, the present invention provides another method for preparing a lithium metal battery. According to an embodiment of the present invention, the method includes: providing a negative electrode plate, the negative electrode plate including a current collector having opposing first and second sides, a first active material layer disposed on the first side of the current collector, the first active material layer comprising metallic lithium, a first metal compound layer disposed on the first active material layer on a side away from the current collector, a fourth active material layer disposed on the second side of the current collector, the fourth active material layer comprising metallic lithium, and a fifth active material layer disposed on a side away from the current collector, the fifth active material layer comprising a metallic lithium alloy; assembling the negative electrode plate into a battery and charging the battery, so that the first metal compound layer forms a first artificial SEI layer in situ during the battery charging process, the first artificial SEI layer comprising a lithium compound and a metallic lithium alloy, wherein the first metal compound layer comprises a compound of at least one of halogen, oxygen, nitrogen, sulfur, and phosphorus and M, wherein M comprises at least one of gold, indium, magnesium, zinc, chromium, nickel, molybdenum, tungsten, vanadium, titanium, niobium, zirconium, cobalt, manganese, aluminum, copper, silver, tin, and bismuth.

[0114] Specifically, in the above method for preparing a lithium metal battery, the battery assembled from the negative electrode sheets can be charged under conditions of 0.01C-50C.

[0115] According to a specific embodiment of the present invention, the first metal compound layer and the second metal compound layer can be formed on the surface of the negative electrode by physical vapor deposition (PVD), chemical vapor deposition (CVD), atomic layer deposition (ALD), etc., by forming a compound of at least one of halogen, oxygen, nitrogen, sulfur, and phosphorus with M, such as at least one of silver fluoride (AgF), magnesium nitride (Mg3N2), and indium tin oxide (ITO). In addition, dry coating, wet coating, etc. can also be used to directly coat the compound of at least one of halogen, oxygen, nitrogen, sulfur, and phosphorus with M on the surface of the negative electrode, such as at least one of silver fluoride (AgF), magnesium nitride (Mg3N2), and indium tin oxide (ITO).

[0116] According to a specific embodiment of the present invention, the first metal compound layer and the second metal compound layer independently include M x+ F - x (i.e., compound of fluorine and M), M x+ O 2- x / 2 (i.e., a compound of oxygen and M), M x+ S 2- x / 2 (i.e., a compound of sulfur and M), M x+ N 3- x / 3 (i.e., a compound of nitrogen and M) and M x+ P3- x / 3 (i.e., a compound of phosphorus and M), during battery charging, M x+ F - x 、M x+ O 2- x / 2 、M x+ S 2- x / 2 、M x+ N 3- x / 3 、M x+ P 3- x / 3 It can react with lithium atoms from the positive electrode during battery charging to generate M and lithium compounds. M can react with metallic lithium to form Li-M alloys. The reactions involved are as follows: M x+ F - x +xLi=M+xLiF, M x+ O 2- x / 2 +x Li=M+x / 2Li2O, M x+ S 2- x / 2 +x Li=M+x / 2Li2S, M x+ N 3- x / 3 +x Li=M+x / 3Li3N, M x+ P 3- x / 3 +x Li=M+x / 3Li3P, M+Li=Li-M.

[0117] It should be noted that M x+ O 2- x / 2 It can be a conductive metal oxide and / or a non-conductive metal oxide. Among them, the conductive metal oxide includes n-type conductive oxides (such as indium tin oxide (ITO), aluminum zinc oxide (AZO), fluorine-doped tin dioxide (FTO), indium tin zinc oxide (ITZO), zinc tin oxide (ZTO), zinc indium tin oxide (ZITO), etc.) and / or p-type conductive oxides (such as copper oxide (CuO), CuM'O (M'=Al, In, Ga, Mg), etc.); the non-conductive metal oxide can be magnesium oxide (MgO), aluminum oxide (Al2O3), zinc oxide (ZnO), silicon oxide (SiO x ), tin oxide (SnO), manganese oxide, zirconium oxide ZrO, etc.

[0118] Therefore, the lithium metal battery obtained by the method for preparing a lithium metal battery of the present invention has high cycle stability and effectively avoids the process complexity caused by multi-layer deposition.

[0119] In its ninth aspect, the present invention provides an electrical device. According to an embodiment of the present invention, the electrical device comprises the aforementioned lithium metal battery or a lithium metal battery obtained by the aforementioned method for preparing a lithium metal battery. The electrical device and the aforementioned lithium metal battery or the aforementioned method for preparing a lithium metal battery have the same advantages over the prior art and are not further elaborated here.

[0120] The present invention is described below with reference to specific examples. It should be noted that these examples are merely illustrative and do not limit the present invention in any way.

[0121] Example 1

[0122] A negative electrode sheet, referring to FIG6 , includes a current collector 10 , a first active material layer 20 , a first artificial SEI layer 30 , a third active material layer 60 and a third artificial SEI layer 70 .

[0123] The current collector 10 includes a first side and a second side relative to each other. The current collector 10 includes a base film 11, a first conductive layer 12 and a second conductive layer 13. The first conductive layer 12 is arranged on the surface of one side of the base film 11, and the second conductive layer 13 is arranged on the surface of the other side opposite to the base film 11. The base film 11 is made of polypropylene with a thickness of 1 μm, the first conductive layer 12 is made of copper with a thickness of 0.3 μm, and the second conductive layer 13 is made of copper with a thickness of 0.3 μm.

[0124] The first active material layer 20 and the first artificial SEI layer 30 are sequentially arranged on the first side of the current collector 10 along the direction away from the current collector 10. The first active material layer 20 includes metallic lithium, and the first artificial SEI layer 30 includes an alloy formed by metallic lithium and magnesium and lithium fluoride. The molar ratio of the alloy formed by metallic lithium and magnesium to lithium fluoride is 1:2; the third active material layer 60 and the third artificial SEI layer 70 are sequentially arranged on the second side of the current collector 10 along the direction away from the current collector 10. The third active material layer 60 includes metallic lithium, and the third artificial SEI layer 70 includes an alloy formed by metallic lithium and magnesium and lithium fluoride. The molar ratio of the alloy formed by metallic lithium and magnesium to lithium fluoride is 1:2. The thickness of the first active material layer 20 and the third active material layer 60 is both 100 μm, and the thickness of the first artificial SEI layer 30 and the third artificial SEI layer 70 is both 1 μm.

[0125] Among them, the first artificial SEI layer 30 and the third artificial SEI layer 70 are both generated by an in-situ method, that is, a metal compound layer including magnesium fluoride is formed on the first active material layer 20 and the third active material layer 60 including metallic lithium, respectively, so that the metal compound layer reacts with lithium atoms from the positive electrode during the battery charging process to generate an alloy formed by metallic lithium and magnesium and lithium fluoride.

[0126] The negative electrode sheet of Example 1 is used to assemble a liquid battery:

[0127] 1. Preparation of positive electrode sheet

[0128] The positive electrode active material LiNi 0.8 Co 0.1 Mn 0.1 O2, conductive agent Super P, and binder polyvinylidene fluoride (PVDF) are prepared into positive electrode slurry in N-methylpyrrolidone (NMP), wherein the solid content in the positive electrode slurry is 50wt%, and the solid content of LiNi 0.8 Co 0.1 Mn 0.1 The mass ratio of O2, Super P and PVDF is 8:1:1. The positive electrode slurry is coated on the upper and lower surfaces of the current collector aluminum foil and dried at 85°C and then cold pressed. Then, it is trimmed, cut and striped, and dried under vacuum conditions at 85°C for 4 hours to make the positive electrode sheet.

[0129] 2. Preparation of electrolyte

[0130] In an argon atmosphere glove box (H2O <0.1ppm, O2 <0.1ppm), the fully dried electrolyte salt LiTFSI was dissolved in a mixed solvent (the mixed solvent included 1,3-dioxolane (DOL) and 1,2-dimethoxyethane (DME), and 1,3-dioxolane (DOL) and 1,2-dimethoxyethane (DME) were mixed in a volume ratio of 50:50), and after mixing evenly, an electrolyte solution with a concentration of 1 mol / L was obtained.

[0131] 3. Isolation film

[0132] A 16 μm polyethylene film was used as the separator.

[0133] 4. Preparation of lithium metal batteries

[0134] The positive electrode sheet, the isolation film, and the negative electrode sheet of Example 1 are stacked in order, so that the isolation film is placed between the positive and negative electrode sheets to isolate the positive and negative electrodes. The bare battery cell is wound and the tabs are welded. The bare battery cell is placed in an outer package, and the electrolyte prepared above is injected into the dried battery cell. The battery cell is packaged, allowed to stand, formed, shaped, and capacity tested to complete the preparation of the lithium metal battery.

[0135] The cycle performance of the lithium metal battery obtained from the negative electrode sheet of Example 1 was characterized.

[0136] Cycling performance test method for lithium metal batteries

[0137] The battery was charged at a constant current of 0.2C at 25°C±2°C until the battery voltage reached 4.2V. The battery was then switched to constant voltage charging until the charging current dropped to 0.05C and charging was stopped. The battery was allowed to stand for 30 minutes after charging and discharged at a current of 0.3C until the battery voltage reached 2.6V. After 50 cycles of the above charge and discharge process, the battery was disassembled and the negative electrode of Example 1 was tested by scanning electron microscope (SEM).

[0138] From the obtained SEM image, it can be seen that the surface of the negative electrode sheet of Example 1 is uniform and relatively flat, and no obvious growth of lithium dendrites is observed.

[0139] It can be seen from Example 1 that the use of the negative electrode plate of the present invention can improve the interface problems of metallic lithium in secondary battery applications, avoid problems such as continuous thickening of the SEI film, continuous growth of lithium dendrites, dead lithium, and lithium dendrites piercing the diaphragm, thereby helping to improve the cycle stability of the lithium metal battery using the negative electrode plate.

[0140] In the description of this specification, the reference terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" mean that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art can combine and combine different embodiments or examples described in this specification and features of different embodiments or examples without contradiction.

[0141] Although the embodiments of the present invention have been shown and described above, it will be understood that the above embodiments are illustrative and are not to be construed as limitations on the present invention. A person skilled in the art may change, modify, replace and modify the above embodiments within the scope of the present invention.

Claims

1. A negative electrode plate, characterized in that: include: a current collector comprising opposing first and second sides; A first active material layer and a first artificial SEI layer, wherein the first active material layer and the first artificial SEI layer are sequentially arranged on a first side of the current collector in a direction away from the current collector, the first active material layer comprises metallic lithium, and the first artificial SEI layer comprises a lithium compound and a metallic lithium alloy.

2. The negative electrode sheet according to claim 1, characterized in that: The current collector is a composite current collector.

3. The negative electrode sheet according to claim 1, characterized in that: The current collector is a metal foil current collector, and the metal foil current collector includes at least one of copper, aluminum, zinc, nickel and chromium.

4. The negative electrode sheet according to claim 1, characterized in that: The current collector includes a base film, a first conductive layer disposed on one side of the base film, and a second conductive layer disposed on the other side opposite to the base film.

5. The negative electrode sheet according to claim 4, characterized in that: The device further includes a second active material layer, which is disposed on the second side of the current collector and includes a metal lithium alloy.

6. The negative electrode sheet according to claim 5, characterized in that: The first active material layer is disposed on the first conductive layer, and the second active material layer is disposed on the second conductive layer.

7. The negative electrode sheet according to claim 6, characterized in that: The invention also includes a second artificial SEI layer, which is arranged on a side of the second active material layer away from the current collector, and the second artificial SEI layer includes a lithium compound.

8. The negative electrode sheet according to claim 4, characterized in that: It also includes a third active material layer and a third artificial SEI layer, which are arranged in sequence on the second side of the current collector in a direction away from the current collector, the third active material layer includes metallic lithium, and the third artificial SEI layer includes lithium compound and metallic lithium alloy.

9. The negative electrode sheet according to claim 8, characterized in that: The first active material layer is disposed on the first conductive layer, and the third active material layer is disposed on the second conductive layer.

10. The negative electrode sheet according to claim 4, characterized in that: It also includes a fourth active material layer and a fifth active material layer, which are sequentially arranged on the second side of the current collector in a direction away from the current collector, the fourth active material layer includes metallic lithium, and the fifth active material layer includes a metallic lithium alloy.

11. The negative electrode sheet according to claim 10, characterized in that: The first active material layer is disposed on the first conductive layer, and the fourth active material layer is disposed on the second conductive layer.

12. The negative electrode sheet according to claim 1, 7 or 8, characterized in that: The lithium compound includes a compound of lithium and at least one of halogen, oxygen, nitrogen, sulfur and phosphorus.

13. The negative electrode sheet according to claim 1 or 5 or 8 or 10, characterized in that: The metal lithium alloy includes an alloy formed by metal lithium and at least one of gold, indium, magnesium, zinc, chromium, nickel, molybdenum, tungsten, vanadium, titanium, niobium, zirconium, cobalt, manganese, aluminum, copper, boron, silver, tin, silicon, carbon, phosphorus and bismuth.

14. The negative electrode sheet according to claim 1, characterized in that: The metal lithium alloy in the first artificial SEI layer includes Li-M, wherein M includes at least one of gold, indium, magnesium, zinc, chromium, nickel, molybdenum, tungsten, vanadium, titanium, niobium, zirconium, cobalt, manganese, aluminum, copper, silver, tin and bismuth, and the molar ratio of the lithium compound in the first artificial SEI layer to the Li-M is (0.1-10):

1.

15. A method for preparing a negative electrode sheet, characterized in that: include: providing a current collector comprising opposing first and second sides; forming a first active material layer on a first side of the current collector, wherein the first active material layer includes metallic lithium; A first artificial SEI layer is formed on the first active material layer at a side away from the current collector, wherein the first artificial SEI layer includes a lithium compound and a metal lithium alloy.

16. The method according to claim 15, characterized in that Also includes: forming a second active material layer on a second side of the current collector, wherein the second active material layer comprises a metallic lithium alloy; A second artificial SEI layer is formed on a side of the second active material layer away from the current collector, wherein the second artificial SEI layer includes a lithium compound.

17. The method according to claim 15, characterized in that Also includes: forming a third active material layer on the second side of the current collector, wherein the third active material layer includes metallic lithium; A third artificial SEI layer is formed on a side of the third active material layer away from the current collector, wherein the third artificial SEI layer includes a lithium compound and a metal lithium alloy.

18. A lithium metal battery, characterized in that: A negative electrode sheet comprising the negative electrode sheet according to any one of claims 1 to 14 or a negative electrode sheet obtained by the method according to any one of claims 15 to 17.

19. The lithium metal battery according to claim 18, characterized in that The lithium metal batteries include liquid batteries, semi-solid batteries and all-solid batteries.

20. The lithium metal battery according to claim 19, characterized in that The lithium metal battery includes a liquid battery and a semi-solid battery. The lithium metal battery includes an electrolyte, and the electrolyte includes a lithium salt and a solvent.

21. The lithium metal battery according to claim 20, characterized in that The lithium salt includes at least one of lithium hexafluorophosphate, lithium perchlorate, lithium tetrafluoroborate, lithium hexafluoroarsenate, lithium trifluoromethylsulfonate, lithium bis(trifluoromethylsulfonyl)imide, lithium bis(fluorosulfonyl)imide, lithium trifluoromethylsulfonyl-perfluorobutylsulfonylimide, lithium fluorosulfonyl-perfluorobutylsulfonylimide, lithium bis(oxalatoborate) and tris(trifluoromethylsulfonyl)methyllithium.

22. The lithium metal battery according to claim 20 or 21, characterized in that: The solvent includes at least one of ethylene carbonate, propylene carbonate, butylene carbonate, dimethyl carbonate, diethyl carbonate, ethyl methyl carbonate, γ-butyrolactone, tetrahydrofuran, 2-methyl-tetrahydrofuran, dimethoxydimethyl ether, 1,2-dimethoxyethane, 1,3-dioxolane and acetonitrile.

23. The lithium metal battery according to claim 22, characterized in that The electrolyte further includes an additive, and the additive includes at least one of a film-forming additive, a conductive additive, a flame retardant additive, an overcharge protection additive, an additive for controlling water and HF content, a low-temperature additive, and a negative electrode stabilizer.

24. The lithium metal battery according to claim 18, characterized in that The lithium metal battery includes a semi-solid battery and an all-solid battery, and the lithium metal battery includes an electrolyte, and the electrolyte includes at least one of an inorganic solid electrolyte, a polymer solid electrolyte and a composite solid electrolyte, and the inorganic solid electrolyte includes at least one of an oxide solid electrolyte, a sulfide solid electrolyte and a halide solid electrolyte.

25. A method for preparing a lithium metal battery, characterized in that: include: Providing a negative electrode plate, the negative electrode plate comprising a current collector having a first side and a second side opposite to each other, the first side of the current collector being provided with a first active material layer, the first active material layer comprising metallic lithium, and a first metal compound layer being provided on a side of the first active material layer away from the current collector; The negative electrode plates are assembled into a battery and charged, so that the first metal compound layer forms a first artificial SEI layer during the battery charging process, wherein the first artificial SEI layer includes a lithium compound and a metal lithium alloy. Among them, the first metal compound layer includes a compound of at least one of halogen, oxygen, nitrogen, sulfur and phosphorus and M, and M includes at least one of gold, indium, magnesium, zinc, chromium, nickel, molybdenum, tungsten, vanadium, titanium, niobium, zirconium, cobalt, manganese, aluminum, copper, silver, tin and bismuth.

26. A method for preparing a lithium metal battery, characterized in that: include: Providing a negative electrode plate, the negative electrode plate comprising a current collector having a first side and a second side opposite to each other, the first side of the current collector being provided with a first active material layer, the first active material layer comprising metallic lithium, a first metal compound layer being provided on a side of the first active material layer away from the current collector, and the second side of the current collector being provided with a second active material layer, the second active material layer comprising a metallic lithium alloy; The negative electrode plates are assembled into a battery and charged, so that the first metal compound layer forms a first artificial SEI layer in situ during the battery charging process, wherein the first artificial SEI layer includes a lithium compound and a metal lithium alloy, Among them, the first metal compound layer includes a compound of at least one of halogen, oxygen, nitrogen, sulfur and phosphorus and M, and M includes at least one of gold, indium, magnesium, zinc, chromium, nickel, molybdenum, tungsten, vanadium, titanium, niobium, zirconium, cobalt, manganese, aluminum, copper, silver, tin and bismuth.

27. A method for preparing a lithium metal battery, characterized in that: include: A negative electrode sheet is provided, the negative electrode sheet comprising a current collector having a first side and a second side opposite to each other, the first side of the current collector is provided with a first active material layer, the first active material layer comprises metallic lithium, a first metal compound layer is provided on a side of the first active material layer away from the current collector, and a second active material layer is provided on the second side of the current collector. The second active material layer comprises a metallic lithium alloy, a second artificial SEI layer is provided on a side of the second active material layer away from the current collector, and the second artificial SEI layer comprises a lithium compound; The negative electrode plates are assembled into a battery and charged, so that the first metal compound layer forms a first artificial SEI layer in situ during the battery charging process, wherein the first artificial SEI layer includes a lithium compound and a metal lithium alloy, Among them, the first metal compound layer includes a compound of at least one of halogen, oxygen, nitrogen, sulfur and phosphorus and M, and M includes at least one of gold, indium, magnesium, zinc, chromium, nickel, molybdenum, tungsten, vanadium, titanium, niobium, zirconium, cobalt, manganese, aluminum, copper, silver, tin and bismuth.

28. A method for preparing a lithium metal battery, characterized in that: include: A negative electrode plate is provided, the negative electrode plate comprising a current collector having a first side and a second side opposite to each other, a first active material layer is provided on the first side of the current collector, the first active material layer comprises metallic lithium, a first metal compound layer is provided on the first active material layer away from the current collector, a third active material layer is provided on the second side of the current collector, the third active material layer comprises metallic lithium, and a second metal compound layer is provided on the third active material layer away from the current collector; The negative electrode plates are assembled into a battery and charged, so that the first metal compound layer forms a first artificial SEI layer in situ during the battery charging process, and the second metal compound layer forms a third artificial SEI layer in situ during the battery charging process, wherein the first artificial SEI layer and the third artificial SEI layer independently include a lithium compound and a metal lithium alloy, respectively. In which, the first metal compound layer and the second metal compound layer independently include a compound of at least one of halogen, oxygen, nitrogen, sulfur and phosphorus and M, and M includes at least one of gold, indium, magnesium, zinc, chromium, nickel, molybdenum, tungsten, vanadium, titanium, niobium, zirconium, cobalt, manganese, aluminum, copper, silver, tin and bismuth.

29. A method for preparing a lithium metal battery, characterized in that: include: A negative electrode plate is provided, the negative electrode plate comprising a current collector having a first side and a second side opposite to each other, a first active material layer is provided on the first side of the current collector, the first active material layer comprises metallic lithium, a first metal compound layer is provided on the first active material layer on a side away from the current collector, a fourth active material layer is provided on the second side of the current collector, the fourth active material layer comprises metallic lithium, a fifth active material layer is provided on a side away from the current collector, the fifth active material layer comprises a metallic lithium alloy; The negative electrode plates are assembled into a battery and charged, so that the first metal compound layer forms a first artificial SEI layer in situ during the battery charging process, wherein the first artificial SEI layer includes a lithium compound and a metal lithium alloy, Among them, the first metal compound layer includes a compound of at least one of halogen, oxygen, nitrogen, sulfur and phosphorus and M, and M includes at least one of gold, indium, magnesium, zinc, chromium, nickel, molybdenum, tungsten, vanadium, titanium, niobium, zirconium, cobalt, manganese, aluminum, copper, silver, tin and bismuth.

30. An electrical device, characterized in that: A lithium metal battery comprising the lithium metal battery according to any one of claims 18 to 24 or a lithium metal battery obtained by the method according to any one of claims 25 to 29.

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