Negative pole piece as well as preparation method and application thereof

Abstract

The invention discloses a negative pole piece as well as a preparation method and application thereof. The negative pole piece comprises: a current collector, wherein the current collector comprises a first side and a second side which are opposite to each other; the first active material layer and the first artificial SEI layer are sequentially arranged on the first side of the current collector in the direction away from the current collector, the first active material layer comprises metal lithium, and the first artificial SEI layer comprises lithiates and metal lithium alloy. By adopting the negative pole piece, the problems of SEI film thickening, lithium dendrite growth, lithium death, diaphragm piercing by the lithium dendrite and the like can be avoided, so that the cycle stability of the lithium metal battery is favorably improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of batteries, and particularly relates to a negative electrode sheet, a preparation method thereof, and an application thereof. Background Art

[0002] Compared with the theoretical specific capacity of 372 mAh / g of a graphite negative electrode, metallic lithium has an ultra-high theoretical specific capacity of 3860 mAh / g and the most negative standard reduction potential (-3.04 V), and has a low density and a small ionic radius. Using it as the negative electrode active material of a battery can further improve the energy density of the battery. However, whether the metallic lithium negative electrode is applied in a solid state system or a liquid state system, it faces technical problems such as the high chemical reactivity of metallic lithium, the thickening of the SEI film caused by an infinitely large volume change rate, the growth of lithium dendrites, dead lithium, and the piercing of the separator by lithium dendrites. Summary of the Invention

[0003] The present invention aims to solve at least one of the technical problems in the related art to some extent. For this purpose, an object of the present invention is to provide a negative electrode sheet, a preparation method thereof, and an application thereof. Using the negative electrode sheet can avoid problems such as the thickening of the SEI film, the growth of lithium dendrites, dead lithium, and the piercing of the separator by lithium dendrites, thereby being beneficial to improving the cycle stability of a lithium metal battery using the negative electrode sheet.

[0004] In the first aspect of the present invention, a negative electrode sheet is provided. According to an embodiment of the present invention, the negative electrode sheet includes:

[0005] A current collector, the current collector including opposite first and second sides;

[0006] A first active material layer and a first artificial SEI layer, the first active material layer and the first artificial SEI layer are sequentially disposed on the first side of the current collector along a direction away from the current collector, the first active material layer includes metallic lithium, and the first artificial SEI layer includes a lithium compound and a metallic lithium alloy.

[0007] According to the negative electrode sheet of the above embodiment of the present invention, by sequentially arranging a first active material layer and a first artificial SEI layer 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 serve as a supplementary lithium source to improve the cycle life of the battery. The first artificial SEI layer includes lithium compounds and metallic lithium alloys. On the one hand, the first artificial SEI layer can prevent the highly reactive metallic lithium in the first active material layer from directly contacting the electrolyte or the electrolyte. On the other hand, the lithium compounds in the first artificial SEI layer are conducive to the rapid migration of lithium ions, thereby effectively avoiding problems such as the growth of lithium dendrites caused by the untimely insertion and extraction of lithium ions at the negative electrode, and the continuous thickening of the SEI film, dead lithium, and the piercing of the separator by lithium dendrites due to an infinitely large 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 problems such as the growth of lithium dendrites caused by the uneven deposition of metallic lithium, and the continuous thickening of the SEI film, dead lithium, and the piercing of the separator by lithium dendrites due to an infinitely large volume change rate. Thus, by using the negative electrode sheet of the present invention, the interfacial problems of metallic lithium in the application of secondary batteries can be improved, and problems such as the continuous thickening of the SEI film, the continuous growth of lithium dendrites, dead lithium, and the piercing of the separator by lithium dendrites can be avoided, thereby being conducive to improving the cycle stability of the lithium metal battery using the negative electrode sheet.

[0008] In addition, the negative electrode sheet according to the above embodiment of the present invention may further have the following additional technical features:

[0009] In some embodiments of the present invention, the current collector is a composite current collector.

[0010] 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.

[0011] 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.

[0012] In some embodiments of the present invention, the above negative electrode sheet 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.

[0013] 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.

[0014] In some embodiments of the present invention, the negative electrode tab further includes a second artificial SEI layer 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.

[0015] In some embodiments of the present invention, the negative electrode tab further 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 sequentially disposed on a 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 a lithium compound and a metallic lithium alloy.

[0016] 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.

[0017] In some embodiments of the present invention, the negative electrode tab further 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 sequentially disposed on a 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.

[0018] 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.

[0019] In some embodiments of the present invention, the lithium compound includes a compound of at least one of halogen, oxygen, nitrogen, sulfur, and phosphorus and lithium. Thereby, the cycle stability of the lithium metal battery can be improved.

[0020] In some embodiments 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. Thereby, the cycle stability of the lithium metal battery can be improved.

[0021] In some embodiments of the present invention, the metallic lithium alloy in the first artificial SEI layer includes Li-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, and the molar ratio of the lithium compound in the first artificial SEI layer to Li-M is (0.1-10):1.

[0022] In a second aspect of the present invention, the present invention provides a method for preparing a negative electrode tab. According to an embodiment of the present invention, the method includes:

[0023] Provide a current collector, the current collector including opposite first and second sides;

[0024] Form a first active material layer on the first side of the current collector, the first active material layer including metallic lithium;

[0025] Form a first artificial SEI layer on the side of the first active material layer away from the current collector, the first artificial SEI layer including lithium compounds and metallic lithium alloy.

[0026] According to the method for preparing a negative electrode sheet of the above embodiment of the present invention, by providing a current collector including opposite first and second sides, forming a first active material layer on the first side of the current collector, and forming a first artificial SEI layer on the side of the first active material layer away from the current collector, the first active material layer including metallic lithium can serve as a supplementary lithium source to improve the cycle life of the battery. The first artificial SEI layer includes lithium compounds and metallic lithium alloy. On the one hand, the first artificial SEI layer can prevent the highly reactive metallic lithium in the first active material layer from directly contacting the electrolyte or electrolyte. On the other hand, the lithium compounds in the first artificial SEI layer are conducive to the rapid migration of lithium ions, thereby effectively avoiding problems such as lithium dendrite growth caused by untimely lithium ion insertion and extraction at the negative electrode, and continuous thickening of the SEI film, dead lithium, and lithium dendrite piercing the separator due to an infinitely large 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 problems such as lithium dendrite growth caused by uneven deposition of metallic lithium, and continuous thickening of the SEI film, dead lithium, and lithium dendrite piercing the separator due to an infinitely large volume change rate. Thus, the negative electrode sheet obtained by using this method can improve the interface problem of metallic lithium in the application of secondary batteries, avoid problems such as continuous thickening of the SEI film, continuous growth of lithium dendrites, dead lithium, and lithium dendrite piercing the separator, thereby being conducive to improving the cycle stability of the lithium metal battery using this negative electrode sheet.

[0027] In addition, the method for preparing a negative electrode sheet according to the above embodiment of the present invention may further have the following additional technical features:

[0028] In some embodiments of the present invention, the above method further includes: forming a second active material layer on the second side of the current collector, the second active material layer including metallic lithium alloy; forming a second artificial SEI layer on the side of the second active material layer away from the current collector, the second artificial SEI layer including lithium compounds.

[0029] In some embodiments of the present invention, the above method further includes: forming a third active material layer on the second side of the current collector, the third active material layer including metallic lithium; forming a third artificial SEI layer on the side of the third active material layer away from the current collector, the third artificial SEI layer including lithium compounds and metallic lithium alloys.

[0030] In a third aspect of the present invention, the present invention provides a lithium metal battery. According to embodiments of the present invention, the lithium metal battery includes the above negative electrode sheet or a negative electrode sheet obtained by the above method. Thus, the lithium metal battery has high cycle stability.

[0031] In addition, the lithium metal battery according to the above embodiments of the present invention may further have the following additional technical features:

[0032] In some embodiments of the present invention, the lithium metal battery includes a liquid battery, a semi-solid battery, and a solid-state battery.

[0033] In some embodiments of the present invention, 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.

[0034] 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 trifluoromethylsulfonyl-n-perfluorobutanesulfonylimide, lithium fluorosulfonyl-n-perfluorobutanesulfonylimide, lithium bis(oxalato)borate, and lithium tris(trifluoromethylsulfonyl)methyl.

[0035] 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.

[0036] In some embodiments of the present invention, 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 the content of water and HF, a low-temperature additive, and a negative electrode stabilizer.

[0037] In some embodiments of the present invention, the lithium metal battery includes a semi-solid battery and a 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 at least one of an oxide solid electrolyte, a sulfide solid electrolyte, and a halide solid electrolyte.

[0038] In a fourth aspect of the present invention, 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 sheet, the negative electrode sheet including a current collector having opposite first and second sides, a first active material layer being provided on the first side of the current collector, 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 sheet into a battery and charging the battery so that the first metal compound layer forms a first artificial SEI layer in-situ during the charging process of the battery, the first artificial SEI layer including lithium compounds and metallic lithium alloys, wherein 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.

[0039] In a fifth 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 sheet, the negative electrode sheet including a current collector having opposite first and second sides, a first active material layer being provided on the first side of the current collector, the first active material layer including metallic lithium, a first metal compound layer being provided on a side of the first active material layer 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; assembling the negative electrode sheet into a battery and charging the battery so that the first metal compound layer forms a first artificial SEI layer in-situ during the charging process of the battery, the first artificial SEI layer including lithium compounds and metallic lithium alloys, wherein 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.

[0040] In a sixth aspect of the present invention, the present invention provides yet another method for preparing a lithium metal battery. According to an embodiment of the present invention, the method includes: providing a negative electrode sheet, the negative electrode sheet including a current collector having opposite first and second sides, a first active material layer being provided on the first side of the current collector, the first active material layer including metallic lithium, a first metal compound layer being provided on a side of the first active material layer 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 a side of the second active material layer away from the current collector, the second artificial SEI layer including a lithium compound; assembling the negative electrode sheet into a battery and charging the battery, so that the first metal compound layer forms a first artificial SEI layer in situ during the charging process of the battery, 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 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 seventh aspect of the present invention, the present invention provides yet another method for preparing a lithium metal battery. According to an embodiment of the present invention, the method includes: providing a negative electrode sheet, the negative electrode sheet including a current collector having opposite first and second sides, a first active material layer being provided on the first side of the current collector, the first active material layer including metallic lithium, a first metal compound layer being provided on a side of the first active material layer away from the current collector, a third active material layer being provided on the second side of the current collector, the third active material layer including metallic lithium, a second metal compound layer being provided on a side of the third active material layer away from the current collector; assembling the negative electrode sheet into a battery and charging the battery, so that the first metal compound layer forms a first artificial SEI layer in situ during the charging process of the battery, and the second metal compound layer forms a third artificial SEI layer in situ during the charging process of the battery, the first artificial SEI layer and the third artificial SEI layer each independently including a lithium compound and a metallic lithium alloy, wherein the first metal compound layer and the second metal compound layer each 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.

[0042] In an eighth aspect of the present invention, the present invention provides yet 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 opposite first and second sides, a first active material layer being disposed on the first side of the current collector, the first active material layer including metallic lithium, a first metal compound layer being disposed on a side of the first active material layer away from the current collector, a fourth active material layer being disposed on the second side of the current collector, the fourth active material layer including metallic lithium, a fifth active material layer being disposed on a side of the fourth active material layer away from the current collector, the fifth active material layer including a lithium metal 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 charging process of the battery, the first artificial SEI layer including a lithium compound and a lithium metal alloy, wherein the first metal compound layer includes a compound of at least one of halogen, oxygen element, nitrogen element, sulfur element, and phosphorus element 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.

[0043] In a ninth aspect of the present invention, the present invention provides an electrical device. According to an embodiment of the present invention, the electrical device includes the above-mentioned lithium metal battery or a lithium metal battery obtained by the above-mentioned method for preparing a lithium metal battery. The advantages of the electrical device over the prior art with respect to the above-mentioned lithium metal battery or the above-mentioned method for preparing a lithium metal battery are the same, and will not be elaborated herein.

[0044] Additional aspects and advantages of the present invention will be given in part in the following description, become apparent in part from the following description, or be learned through the practice of the present invention. Description of the Drawings

[0045] The above and / or additional aspects and advantages of the present invention will become apparent and be readily understood from the description of the embodiments in conjunction with the following drawings, in which:

[0046] Figure 1 is a schematic structural view of a negative electrode plate according to an embodiment of the present invention;

[0047] Figure 2 is a schematic structural view of a current collector according to an embodiment of the present invention;

[0048] Figure 3 is a schematic structural view of a negative electrode plate according to another embodiment of the present invention;

[0049] Figure 4 is a schematic structural view of a negative electrode plate according to yet another embodiment of the present invention;

[0050] Figure 5It is a schematic structural diagram of a negative electrode plate according to another embodiment of the present invention;

[0051] Figure 6 It is a schematic structural diagram of a negative electrode plate according to another embodiment of the present invention;

[0052] Figure 7 It is a schematic structural diagram of a negative electrode plate according to another embodiment of the present invention;

[0053] Figure 8 It is a schematic process flow diagram of a method for preparing a negative electrode plate according to an embodiment of the present invention.

[0054] Reference numerals:

[0055] 1000 - negative electrode plate; 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 of the embodiments

[0056] The embodiments of the present invention will be described in detail below. Examples of the embodiments are shown in the drawings, where the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the drawings are exemplary and are intended to explain the present invention and should not be construed as limiting the present invention.

[0057] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply 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 construed as limiting the present invention.

[0058] In addition, the terms "first" and "second" are only used for descriptive purposes and should not be construed as indicating or implying relative importance or implicitly indicating the quantity of the indicated technical features. Thus, features defined with "first" and "second" may explicitly or implicitly include at least one of such features. In the description of the present invention, "a plurality" means at least two, such as two, three, etc., unless otherwise specifically and clearly defined.

[0059] In the first aspect of the present invention, the present invention provides a negative electrode tab. According to an embodiment of the present invention, referring to Figure 1 , the negative electrode tab 1000 includes a current collector 10, a first active material layer 20, and a first artificial SEI (solid electrolyte interface) layer 30.

[0060] According to an embodiment of the present invention, the current collector 10 includes opposite first and second sides. 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 1 μm - 10 μm, such as 1 μm, 2 μm, 3 μm, 4 μm, 5 μm, 6 μm, 7 μm, 8 μm, 9 μm, 10 μm, etc. Among them, 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, copper-nickel alloy, and copper-zinc alloy. The thickness of the metal foil current collector is preferably 4 μm - 10 μm.

[0061] According to a specific embodiment of the present invention, referring to Figure 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.

[0062] According to a specific embodiment of the present invention, the material of the base film 11 can be a polymer. Since the base film 11 has a lower density than metal foils such as copper foil, the current collector 10 prepared therefrom also has a lower density than metal foil current collectors such as copper foil, thereby improving the energy density of the battery.

[0063] 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; alternatively, the base film 11 includes PI and / or PPS, and PI and PPS have a flame retardant effect, which can reduce the fire problem caused by lithium dendrite piercing the film short circuit.

[0064] According to a specific embodiment of the present invention, the thickness of the base film 11 can be 1 μm - 10 μm, such as 1 μm, 2 μm, 3 μm, 4 μm, 5 μm, 6 μm, 7 μm, 8 μm, 9 μm, 10 μm, etc.

[0065] According to a specific embodiment of the present invention, referring to Figure 2, the first conductive layer 12 is disposed on one side of the base film 11, and the second conductive layer 13 is disposed on the opposite side of the base film 11. By providing 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.

[0066] According to a specific embodiment of the present invention, the first conductive layer 12 and the second conductive layer 13 each independently include at least one of copper, aluminum, zinc, nickel, and chromium. The thicknesses of the first conductive layer 12 and the second conductive layer 13 can each independently be 0.3 μm - 10 μm, such as 0.3 μm, 0.5 μm, 1 μm, 3 μm, 5 μm, 7 μm, 9 μm, 10 μm, etc.

[0067] According to a specific embodiment of the present invention, the first conductive layer 12 and the second conductive layer 13 can each independently be prepared by physical vapor deposition (PVD), chemical vapor deposition (CVD), or 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. Among them, the one-step method includes a one-step chemical deposition method, a one-step vacuum magnetron sputtering method, and a one-step vacuum evaporation method. The one-step chemical deposition method deposits a copper layer through a chemical reaction. The one-step vacuum magnetron sputtering method deposits a copper layer through repeated magnetron sputtering. The one-step vacuum evaporation method deposits a copper layer through repeated evaporation. The two-step method first uses magnetron sputtering for priming and then uses electroplating to thicken the copper layer. The three-step method first uses magnetron sputtering for priming, then uses vacuum evaporation, and finally uses electroplating to thicken the copper layer.

[0068] Thus, by using a composite current collector for the negative electrode sheet 1000 of the present invention, on the one hand, the mechanical strength and mechanical properties of the negative electrode sheet 1000 can be improved. 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.

[0069] According to an embodiment of the present invention, refer to Figure 1, the first active material layer 20 and the first artificial SEI layer 30 are sequentially disposed 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, and the first artificial SEI layer 30 includes a lithium compound and a metallic lithium alloy. The inventors found that by sequentially disposing 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, and the first active material layer 20 includes metallic lithium, it can serve as a supplementary lithium source to improve the cycle life of the battery. 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 highly reactive metallic lithium 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 problems such as the growth of lithium dendrites caused by the untimely insertion and extraction of lithium ions at the negative electrode, and the continuous thickening of the SEI film, dead lithium, and the piercing of the separator by lithium dendrites due to an infinitely large 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 charge and discharge process of the battery, which is conducive to the uniform deposition of metallic lithium, thereby effectively avoiding problems such as the growth of lithium dendrites caused by the non-uniform deposition of metallic lithium, and the continuous thickening of the SEI film, dead lithium, and the piercing of the separator by lithium dendrites due to an infinitely large volume change rate. Thus, by using the negative electrode sheet 1000 of the present invention, the interfacial problems of metallic lithium in the application of secondary batteries can be improved, and problems such as the continuous thickening of the SEI film, the continuous growth of lithium dendrites, dead lithium, and the piercing of the separator by lithium dendrites can be avoided, thereby being conducive to improving the cycle stability of the lithium metal battery using the negative electrode sheet 1000.

[0070] According to a specific embodiment of the present invention, referring to Figure 3 , the first active material layer 20 is disposed on the first conductive layer 12.

[0071] According to a specific embodiment of the present invention, the thickness of the first active material layer 20 can be 0.1 μm - 100 μm, for example, it can be 0.1 μm, 0.5 μm, 1 μm, 5 μm, 10 μm, 30 μm, 50 μm, 70 μm, 90 μm, 100 μm, etc. The thickness of the first artificial SEI layer 30 can be 0.1 μm - 1 μm, for example, it can be 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.

[0072] According to a specific embodiment of the present invention, the lithium compound includes at least one compound of lithium element and halogen (such as fluorine element), oxygen element, nitrogen element, sulfur element, and phosphorus element. Optionally, the lithium compound includes lithium fluoride (LiF), lithium oxide (Li 2 O), lithium sulfide (Li 2 S), lithium nitride (Li3 N), lithium phosphide (Li 3 P), and at least one of lithium phosphonitride (LiPON).

[0073] 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 element in the metallic lithium alloy can be 0.1 atm% - 99.9 atm%, for example, it can be 0.1 atm%, 1 atm%, 2 atm%, 5 atm%, 15 atm%, 35 atm%, 55 atm%, 75 atm%, 95 atm%, 99.9 atm%, etc.

[0074] According to a specific embodiment of the present invention, the metallic lithium alloy in the first artificial SEI layer 30 includes Li-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, 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.

[0075] According to a specific embodiment of the present invention, referring to Figure 4 , the negative electrode plate 1000 further includes a second active material layer 40, the second active material layer 40 is disposed on the second side of the current collector 10, and the second active material layer 40 includes a metallic lithium alloy. By disposing the second active material layer 40 including the metallic lithium alloy on the second side of the current collector 10, an alloying reaction can occur between metallic lithium and the metallic lithium alloy in the second active material layer 40 during the charge and discharge process of the battery, which is further beneficial to avoiding problems such as lithium dendrite growth caused by uneven deposition of metallic lithium, continuous thickening of the SEI film, dead lithium, and lithium dendrite piercing the separator due to an infinitely large 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, it can be 0.1 μm, 0.5 μm, 1 μm, 5 μm, 10 μm, 30 μm, 50 μm, 70 μm, 90 μm, 100 μm, etc.

[0076] According to a specific embodiment of the present invention, referring to Figure 5, the negative electrode sheet 1000 further includes a second artificial SEI layer 50, and the second artificial SEI layer 50 is disposed on the side of the second active material layer 40 away from the current collector 10. The second artificial SEI layer 50 includes a lithium compound. By disposing the second artificial SEI layer 50 including a lithium compound on the side of the second active material layer 40 away from the current collector 10, it is further beneficial to the rapid migration of lithium ions, thereby effectively avoiding problems such as lithium dendrite growth caused by untimely lithium ion insertion and extraction in the negative electrode, and continuous thickening of the SEI film, dead lithium, and lithium dendrite piercing the separator due to an infinite volume change rate, thus further contributing to improving the cycle stability of the lithium metal battery. Specifically, the thickness of the second artificial SEI layer 50 can be 0.1 μm - 1 μm, for example, it can be 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.

[0077] According to a specific embodiment of the present invention, referring to Figure 6, the negative electrode sheet 1000 further 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 lithium compound and a metallic lithium alloy. By sequentially arranging the third active material layer 60 and the third artificial SEI layer 70 on the second side of the current collector 10 in a direction away from the current collector 10, and the third active material layer 60 includes metallic lithium, it can serve 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 problems such as the growth of lithium dendrites caused by the untimely insertion and extraction of lithium ions at the negative electrode, and the continuous thickening of the SEI film, dead lithium, and the piercing of the separator by lithium dendrites due to an infinitely large 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, further facilitating the avoidance of problems such as the growth of lithium dendrites caused by the uneven deposition of metallic lithium, and the continuous thickening of the SEI film, dead lithium, and the piercing of the separator by lithium dendrites due to an infinitely large 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 disposed on the second conductive layer 13, and the thickness of the third active material layer 60 can be 0.1 μm - 100 μm, for example, it can be 0.1 μm, 0.5 μm, 1 μm, 5 μm, 10 μm, 30 μm, 50 μm, 70 μm, 90 μm, 100 μm, etc., and the thickness of the third artificial SEI layer 70 can be 0.1 μm - 1 μm, for example, it can be 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.

[0078] According to a specific embodiment of the present invention, the metallic 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. The molar ratio of the lithium compound in the third artificial SEI layer 70 to Li-M 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.

[0079] According to a specific embodiment of the present invention, refer to Figure 7, the negative electrode plate 1000 further 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, and the fourth active material layer 80 includes metallic lithium, it can serve as a supplementary lithium source to improve the cycle life of the battery. The fifth active material layer 90 includes a metallic lithium alloy. On the one hand, it can prevent the metallic lithium in the fourth active material layer 80 from directly contacting the electrolyte or the electrolyte. On the other hand, during the charge and discharge process of the battery, alloying reaction occurs between the metallic lithium and the metallic lithium alloy in the fifth active material layer 90, effectively avoiding problems such as uneven deposition of metallic lithium causing lithium dendrite growth, continuous thickening of the SEI film, dead lithium, and lithium dendrite piercing the separator due to an infinitely large volume change rate, thereby being beneficial to improving the cycle stability of the lithium metal battery using the negative electrode plate 1000. Specifically, the fourth active material layer 80 can be disposed on the second conductive layer 13, and the thicknesses of the fourth active material layer 80 and the fifth active material layer 90 can be independently 0.1 μm - 100 μm respectively, for example, they can be 0.1 μm, 0.5 μm, 1 μm, 5 μm, 10 μm, 30 μm, 50 μm, 70 μm, 90 μm, 100 μm, etc.

[0080] 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 roll pressing (i.e., roll pressing a metal strip serving as the active material layer onto the surface of the current collector or other active material layers) or physical vapor deposition (PVD, such as magnetron sputtering, vacuum evaporation, etc.). The physical vapor deposition method is preferred. Thus, it is beneficial to reduce the thickness of the active material layer, achieve uniform deposition, thereby reducing the usage amount of the active material and lowering the cost. Optionally, the metallic lithium alloy Li-M can be formed by magnetron sputtering a metal M onto the surface of the metallic lithium layer to form an active material layer including the metallic lithium alloy. Alternatively, the metallic lithium alloy Li-M can be prepared by vacuum evaporation, that is, metallic lithium and metal M in the form of strips, blocks, etc. are placed in a container (such as an evaporation boat, crucible, etc.). Considering the melting points of metallic lithium 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 adopted under the premise of setting a reasonable evaporation chamber pressure and substrate temperature to control the composition and deposition rate of the metallic lithium alloy.

[0081] According to specific embodiments of the present invention, the second artificial SEI layer 50 can directly form a compound formed by metallic lithium and elements such as halogen, oxygen, nitrogen, sulfur, and phosphorus, such as lithium fluoride, lithium oxide, lithium nitride, lithium sulfide, lithium phosphide, etc., by means of physical vapor deposition (PVD), chemical vapor deposition (CVD), atomic layer deposition (ALD), etc. Further, lithium phosphate (Li 3 PO 4 ) is magnetron sputtered in a nitrogen atmosphere to generate a lithium phosphorus oxygen nitrogen compound (LiPON). In addition, methods such as dry coating and wet coating can also be used to directly coat a compound formed by lithium element and elements such as halogen, oxygen, nitrogen, sulfur, and phosphorus onto the surface of the negative electrode, such as lithium fluoride (LiF), lithium oxide (Li 2 O), lithium sulfide (Li 2 S), lithium nitride (Li 3 N), lithium phosphide (Li 3 P), and at least one of lithium phosphorus oxygen nitrogen compound (LiPON).

[0082] According to specific embodiments of the present invention, the first artificial SEI layer 30 and the third artificial SEI layer 70 can be independently formed by an in-situ method, that is, a metal compound layer including a compound of at least one of halogen, oxygen, nitrogen, sulfur, and phosphorus and M is independently formed on the first active material layer 20 and the third active material layer 60 including metallic lithium, so that the metal compound layer reacts with lithium atoms derived from the positive electrode during the charging process of the battery to generate a lithium compound and a metallic lithium alloy. Thereby, the process complexity caused by multi-layer deposition is effectively avoided.

[0083] Thereby, by using the negative electrode sheet 1000 of the present invention, the interface problem of metallic lithium in the application of secondary batteries can be improved, and problems such as continuous thickening of the SEI film, continuous growth of lithium dendrites, dead lithium, and lithium dendrites piercing the separator can be avoided, thereby being beneficial to improving the cycle stability of lithium metal batteries.

[0084] In the second aspect of the present invention, referring to Figure 8 , the present invention proposes a method for preparing a negative electrode sheet. Referring to Figure 8 , according to an embodiment of the present invention, the method includes:

[0085] S100: Provide a current collector, the current collector including opposite first and second sides

[0086] In this step, a current collector 10 is provided, and the current collector 10 includes opposite first and second sides. It should be noted that the specific method for preparing the current collector 10 is not particularly limited. For example, it may include: forming a first conductive layer 12 on one side of a base film 11; forming a second conductive layer 13 on the side of the base film 11 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.

[0087] S200: Form a first active material layer on the first side of the current collector, and the first active material layer includes metallic lithium

[0088] In this step, a first active material layer 20 is formed on the first side of the current collector 10, and the first active material layer 20 includes metallic lithium. The inventors found that by forming the first active material layer 20 including metallic lithium on the first side of the current collector 10, it can serve as a supplementary lithium source and improve the cycle life of the battery. Specifically, the first active material layer 20 can be formed on the first conductive layer 12.

[0089] S300: Form a first artificial SEI layer on the side of the first active material layer away from the current collector, and the first artificial SEI layer includes lithium compounds and metallic lithium alloys

[0090] In this step, a first artificial SEI layer 30 is formed on the side of the first active material layer 20 away from the current collector 10, and the first artificial SEI layer 30 includes lithium compounds and metallic lithium alloys. The inventors found that by forming the first artificial SEI layer 30 including lithium compounds and metallic lithium alloys 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 highly reactive metallic lithium in the first active material layer 20 from directly contacting the electrolyte or the electrolyte. On the other hand, the lithium compounds in the first artificial SEI layer 30 are beneficial to the rapid migration of lithium ions, thus effectively avoiding problems such as the growth of lithium dendrites caused by the untimely insertion and extraction of lithium ions at the negative electrode, and the continuous thickening of the SEI film, dead lithium, and the piercing of the separator by lithium dendrites due to an infinitely large volume change rate. On the other hand, the metallic lithium alloys in the first artificial SEI layer 30 can undergo an alloying reaction with metallic lithium during the charge and discharge process of the battery, which is beneficial to the uniform deposition of metallic lithium, thus effectively avoiding problems such as the growth of lithium dendrites caused by the uneven deposition of metallic lithium, and the continuous thickening of the SEI film, dead lithium, and the piercing of the separator by lithium dendrites due to an infinitely large volume change rate.

[0091] Therefore, the negative electrode plate obtained by using the method for preparing the negative electrode plate of the present invention can improve the interface problems of metallic lithium in the application of secondary batteries, avoid problems such as the continuous thickening of the SEI film, the continuous growth of lithium dendrites, dead lithium, and the piercing of the separator by lithium dendrites, thereby being beneficial to improving the cycle stability of lithium metal batteries.

[0092] According to a specific embodiment of the present invention, the above 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 including a lithium metal alloy; 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 including a lithium compound. Thereby, the cycle stability of the lithium metal battery can be improved. By forming the second active material layer 40 including lithium metal on the second side of the current collector 10, it can serve as a supplementary lithium source and improve the cycle life of the battery. By forming the second artificial SEI layer 50 including a lithium compound on the side of the second active material layer 40 away from the current collector 10, on the one hand, it can prevent the lithium metal in the second active material layer 40 from directly contacting the electrolyte or the electrolyte, and on the other hand, it is beneficial to the rapid migration of lithium ions. Thereby, it effectively avoids problems such as the growth of lithium dendrites caused by the untimely insertion and extraction of lithium ions at the negative electrode, and the continuous thickening of the SEI film, dead lithium, and the piercing of the separator by lithium dendrites due to an infinitely large volume change rate, thus further facilitating the improvement of the cycle stability of the lithium metal battery.

[0093] According to a specific embodiment of the present invention, the above method further includes: forming a third active material layer 60 on the second side of the current collector 10, the third active material layer 60 including lithium metal; 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 including a lithium compound and a lithium metal alloy. The inventors found that by forming the third active material layer 60 including lithium metal on the second side of the current collector 10, it can serve as a supplementary lithium source and improve the cycle life of the battery. By forming the third artificial SEI layer 70 including a lithium compound and a lithium metal alloy 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 lithium metal 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 is beneficial to the rapid migration of lithium ions, thereby effectively avoiding problems such as the growth of lithium dendrites caused by the untimely insertion and extraction of lithium ions at the negative electrode, and the continuous thickening of the SEI film, dead lithium, and the piercing of the separator by lithium dendrites due to an infinitely large volume change rate. On the other hand, the lithium metal alloy in the third artificial SEI layer 70 can undergo an alloying reaction with lithium metal during the charge and discharge process of the battery, effectively avoiding problems such as the growth of lithium dendrites caused by the uneven deposition of lithium metal, and the continuous thickening of the SEI film, dead lithium, and the piercing of the separator by lithium dendrites due to an infinitely large volume change rate.

[0094] 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 elaborated here.

[0095] In the third aspect of the present invention, the present invention provides a lithium metal battery. According to an embodiment of the present invention, the lithium metal battery includes the above-mentioned negative electrode sheet or the negative electrode sheet obtained by the above method. Thus, the lithium metal battery has high cycle stability. It should be noted that the features and advantages described above for the negative electrode sheet also apply to the lithium metal battery and will not be elaborated here.

[0096] According to a specific embodiment of the present invention, the above lithium metal battery includes a liquid battery, a semi-solid battery, and a solid-state battery.

[0097] According to a specific embodiment of the present invention, the above lithium metal battery includes a liquid battery and a semi-solid battery, and the lithium metal battery includes an electrolyte.

[0098] According to a specific embodiment of the present invention, the above lithium metal battery includes a liquid laminated soft-pack battery, a liquid wound battery, or a liquid cylindrical battery composed of the above-mentioned negative electrode sheet or the negative electrode sheet obtained by the above method for preparing the negative electrode sheet, a positive electrode sheet, a separator, and an electrolyte.

[0099] According to a specific embodiment of the present invention, the above lithium metal battery further includes a semi-solid laminated soft-pack battery, a semi-solid wound battery, or a semi-solid cylindrical battery composed of the above-mentioned negative electrode sheet or the negative electrode sheet obtained by the above method for preparing the negative electrode sheet, a positive electrode sheet, and a gel electrolyte.

[0100] According to a specific embodiment of the present invention, the above lithium metal battery further includes a semi-solid laminated soft-pack battery, a semi-solid wound battery, or a semi-solid cylindrical battery composed of the above-mentioned negative electrode sheet or the negative electrode sheet obtained by the above method for preparing the negative electrode sheet, a positive electrode sheet, a gel electrolyte, and an optional additive of 0.5 wt% - 50 wt%.

[0101] According to specific embodiments 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.; the lithium salt may include lithium hexafluorophosphate (LiPF 6 ), lithium perchlorate (LiClO 4 ), lithium tetrafluoroborate (LiBF 4 ), lithium hexafluoroarsenate (LiAsF 6 ), other organic lithium salts (such as lithium trifluoromethanesulfonate (LiCF 3 SO), lithium bis(trifluoromethanesulfonyl)imide (LiTFSI), lithium bis(fluorosulfonyl)imide (LiFSI), lithium trifluoromethylsulfonyl-n-perfluorobutanesulfonylimide (LiTNFSI), lithium fluorosulfonyl-n-perfluorobutanesulfonylimide (LiFNFSI), lithium bis(oxalato)borate (LiBOB), lithium tris(trifluoromethylsulfonyl)methyl (LiC(SO 2 CF 3 )) 3 ), etc.); the additive may include a film-forming additive, a conductive additive, a flame retardant additive, an overcharge protection additive, an additive for controlling the content of water and HF (i.e., an additive for controlling the content of water and HF in the electrolyte), a low-temperature additive (i.e., a general additive for improving low-temperature performance), and may also include a negative electrode stabilizer, i.e., an additive for improving the interfacial stability of the lithium metal negative electrode (such as fluoroethylene carbonate (FEC), lithium nitrate (LiNO 3 ), etc.).

[0102] According to specific embodiments of the present invention, the above-mentioned lithium metal battery includes a semi-solid battery and a 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.

[0103] According to specific embodiments of the present invention, the above-mentioned lithium metal battery further includes a solid-state laminated soft-pack battery, a solid-state wound battery, or a solid-state cylindrical battery composed of the above-mentioned negative electrode sheet or a negative electrode sheet obtained by using the method for preparing the negative electrode sheet, a positive electrode sheet, and a solid electrolyte.

[0104] According to specific embodiments of the present invention, the above-mentioned positive electrode tab can be a positive electrode tab using a metal foil current collector or a positive electrode tab using a composite current collector, and its positive electrode active material includes lithium nickel cobalt manganate (LiN x M y C z O 2 , x + y + z = 1), lithium iron manganese phosphate (LiFe a Mn b PO 4 , a + b = 1), lithium iron phosphate, lithium manganate, lithium cobaltate, lithium nickelate, lithium-rich manganese-based positive electrode material, lithium nickel manganate (LMNO), and lithium vanadium phosphate (Li 3 V 2 (PO 4 ) 3 , LiVOPO 4 ), and at least one of them.

[0105] According to specific embodiments of the present invention, the above-mentioned separator includes polypropylene (PP) and / or polyethylene (PE).

[0106] According to specific embodiments of the present invention, the above-mentioned solid electrolyte includes inorganic solid electrolytes (such as oxide solid electrolytes, sulfide solid electrolytes, halide solid electrolytes), polymer solid electrolytes, and composite solid electrolytes (such as composite solid electrolytes based on polymer matrices and inorganic fillers), etc. Specifically, the oxide solid electrolyte can include NASICON type (structurally stable, such as LATP (Li 1.3 Al 0.3 Ti 1.7 (PO 4 ) 3 ), LAGP (Li 1.5 Al 0.5 Ge 1.5 P 3 O 12 ), perovskite type, garnet type (with the highest conductivity, 10 -3 S / cm, and relatively good stability against metallic lithium, such as lithium lanthanum zirconium oxide (LLZO)); the sulfide solid electrolyte can include binary compounds (such as Li 2 S - SiS 2 and Li 2 S - P 2 S 5 , Li 2 S - GeS 2 etc.), ternary compounds (such as Li 2 S - MS 2 - P 2 S 5 (M = Si, Ge, Sn, Al, etc.), and Li6 PS 5 X (X = F, Cl, Br, I) type; the halide solid electrolyte may include Li a MX 4 type (X represents a halogen element, such as Li formed by divalent metal ions 2 MnCl 4 、Li 2 ZnCl 4 etc., and halide electrolytes formed by trivalent and other valence metal ions M, such as LiYbF 4 、LiAlF 4 ), Li a MX 6 type (such as Li 3 YCl 6 (LYC) and Li 3 BrCl 6 (LYB)) and Li a MX 8 type (such as Li 6 CoCl 8 ). The polymer solid electrolyte may include polymer matrices such as polyethylene oxide (PEO), polycarbonate, poly(trimethylene carbonate) (PTMC), polymethyl methacrylate (PMMA), polyacrylonitrile (PAN), polyvinylidene fluoride (PVDF), poly(vinylidene fluoride - hexafluoroethylene) copolymer, lithium polyacrylate (PAL), etc., inorganic fillers such as LATP, lithium lanthanum zirconium oxide (LLZO), aluminum oxide (Al 2 O 3 ), metal - organic frameworks (MOFs), etc., and lithium salts such as LiAsF 6 、lithium hexafluorophosphate (LiPF 6 ), lithium perchlorate (LiClO 4 ), lithium bis(trifluoromethanesulfonyl)imide (LiTFSI), lithium bis(fluorosulfonyl)imide (LiFSI), lithium tetrafluoroborate (LiBF 4 ). Specifically, the gel electrolyte may include at least one of the above - mentioned solid electrolytes and at least one of the above - mentioned electrolytes.

[0107] In a fourth aspect of the present invention, 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 sheet, the negative electrode sheet including a current collector having opposite first and second sides, a first active material layer being disposed on the first side of the current collector, the first active material layer including metallic lithium, a first metal compound layer being disposed on a side of the first active material layer away from the current collector; assembling the negative electrode sheet into a battery and charging the battery so that the first metal compound layer forms a first artificial SEI layer in-situ during the charging process of the battery, 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 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.

[0108] In a fifth aspect of the present invention, the present invention provides yet another method for preparing a lithium metal battery. According to an embodiment of the present invention, the method includes: providing a negative electrode sheet, the negative electrode sheet including a current collector having opposite first and second sides, a first active material layer being disposed on the first side of the current collector, the first active material layer including metallic lithium, a first metal compound layer being disposed on a side of the first active material layer away from the current collector, a second active material layer being disposed on the second side of the current collector, the second active material layer including a metallic lithium alloy; assembling the negative electrode sheet into a battery and charging the battery so that the first metal compound layer forms a first artificial SEI layer in-situ during the charging process of the battery, 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 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.

[0109] In a sixth aspect of the present invention, the present invention proposes yet another method for preparing a lithium metal battery. According to an embodiment of the present invention, the method includes: providing a negative electrode sheet, the negative electrode sheet including a current collector having opposite first and second sides, a first active material layer being provided on the first side of the current collector, the first active material layer including metallic lithium, a first metal compound layer being provided on a side of the first active material layer 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 lithium metal alloy, a second artificial SEI layer being provided on a side of the second active material layer away from the current collector, the second artificial SEI layer including a lithium compound; assembling the negative electrode sheet into a battery and charging the battery so that the first metal compound layer forms a first artificial SEI layer in-situ during the charging process of the battery, the first artificial SEI layer including a lithium compound and a lithium metal alloy, wherein the first metal compound layer includes a compound of at least one of halogen, oxygen element, nitrogen element, sulfur element and phosphorus element 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.

[0110] In a seventh aspect of the present invention, the present invention proposes yet another method for preparing a lithium metal battery. According to an embodiment of the present invention, the method includes: providing a negative electrode sheet, the negative electrode sheet including a current collector having opposite first and second sides, a first active material layer being provided on the first side of the current collector, the first active material layer including metallic lithium, a first metal compound layer being provided on a side of the first active material layer away from the current collector, a third active material layer being provided on the second side of the current collector, the third active material layer including metallic lithium, a second metal compound layer being provided on a side of the third active material layer away from the current collector; assembling the negative electrode sheet into a battery and charging the battery so that the first metal compound layer forms a first artificial SEI layer in-situ during the charging process of the battery, and the second metal compound layer forms a third artificial SEI layer in-situ during the charging process of the battery, the first artificial SEI layer and the third artificial SEI layer each independently include a lithium compound and a lithium metal alloy, wherein the first metal compound layer and the second metal compound layer each independently include a compound of at least one of halogen, oxygen element, nitrogen element, sulfur element and phosphorus element 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.

[0111] In the eighth aspect of the present invention, the present invention proposes yet 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 opposite first and second sides, a first active material layer being provided on the first side of the current collector, the first active material layer including metallic lithium, a first metal compound layer being provided on a side of the first active material layer away from the current collector, a fourth active material layer being provided on the second side of the current collector, the fourth active material layer including metallic lithium, a fifth active material layer being provided on a side of the fourth active material layer away from the current collector, the fifth active material layer including a lithium metal alloy; assembling the negative electrode plate into a battery and charging it to form a first artificial SEI layer in situ on the first metal compound layer during the charging process of the battery, the first artificial SEI layer including a lithium compound and a lithium metal alloy, wherein the first metal compound layer includes a compound of at least one of halogen, oxygen element, nitrogen element, sulfur element, and phosphorus element 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.

[0112] Specifically, in the above method for preparing a lithium metal battery, the battery assembled from the negative electrode plate can be charged under the condition of 0.01C - 50C.

[0113] According to a specific embodiment of the present invention, the first metal compound layer and the second metal compound layer can form a compound of at least one of halogen, oxygen element, nitrogen element, sulfur element, and phosphorus element and M on the surface of the negative electrode by means of physical vapor deposition (PVD), chemical vapor deposition (CVD), atomic layer deposition (ALD), etc., such as at least one of silver fluoride (AgF), magnesium nitride (Mg 3 N 2 ), indium tin oxide (ITO). In addition, methods such as dry coating and wet coating can also be used to directly coat a compound of at least one of halogen, oxygen element, nitrogen element, sulfur element, and phosphorus element and M on the surface of the negative electrode, such as at least one of silver fluoride (AgF), magnesium nitride (Mg 3 N 2 )、 indium tin oxide (ITO).

[0114] According to a specific embodiment of the present invention, the first metal compound layer and the second metal compound layer each independently include M x+ F - x (i.e., a 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+ N3- x / 3 (i.e., the compound of nitrogen and M) and M x+ P 3- x / 3 (i.e., the compound of phosphorus and M) or at least one of them, during the battery charging process, 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 can react with lithium atoms from the positive electrode during the battery charging process to form M and lithium compounds. M can undergo an alloying reaction with metallic lithium to form a Li-M alloy. The reactions involved are as follows:

[0115] M x+ F - x +x Li = M + x LiF,

[0116] M x+ O 2- x / 2 +x Li = M + x / 2Li 2 O,

[0117] M x+ S 2- x / 2 +x Li = M + x / 2Li 2 S,

[0118] M x+ N 3- x / 3 +x Li = M + x / 3Li 3 N,

[0119] M x+ P 3- x / 3 +x Li = M + x / 3Li 3 P,

[0120] M + Li = Li - M.

[0121] It should be noted that M x+ O 2- x / 2It can be a conductive metal oxide and / or a non-conductive metal oxide. Among them, the conductive metal oxides include 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 oxides can be magnesium oxide (MgO), aluminum oxide (Al 2 O 3 ), zinc oxide (ZnO), silicon oxide (SiO x ), tin oxide (SnO), manganese oxide, zirconium oxide ZrO, etc.

[0122] Thus, 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.

[0123] In a ninth aspect of the present invention, the present invention provides an electrical device. According to an embodiment of the present invention, the electrical device includes the above-mentioned lithium metal battery or a lithium metal battery obtained by the above-mentioned method for preparing a lithium metal battery. The advantages of the electrical device and the above-mentioned lithium metal battery or the above-mentioned method for preparing a lithium metal battery over the prior art are the same and will not be elaborated herein.

[0124] Next, the present invention will be described with reference to specific embodiments. It should be noted that these embodiments are merely illustrative and do not limit the present invention in any way.

[0125] Example 1

[0126] A negative electrode plate, referring to Figure 6 , 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.

[0127] The current collector 10 includes opposite first and second sides. 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 provided on the surface of one side of the base film 11, and the second conductive layer 13 is provided on the surface of the opposite side of the base film 11. The material of the base film 11 is polypropylene with a thickness of 1 μm, the material of the first conductive layer 12 is copper with a thickness of 0.3 μm, and the material of the second conductive layer 13 is copper with a thickness of 0.3 μm.

[0128] The first active material layer 20 and the first artificial SEI layer 30 are sequentially disposed 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, 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 disposed 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 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 thicknesses of both the first active material layer 20 and the third active material layer 60 are 100 μm, and the thicknesses of both the first artificial SEI layer 30 and the third artificial SEI layer 70 are 1 μm.

[0129] Among them, both the first artificial SEI layer 30 and the third artificial SEI layer 70 are formed by an in-situ method, that is, a metal compound layer including magnesium fluoride is respectively formed on the first active material layer 20 and the third active material layer 60 including metallic lithium, and the metal compound layer reacts with lithium atoms from the positive electrode during the charging process of the battery to generate an alloy formed by metallic lithium and magnesium and lithium fluoride.

[0130] Assemble the negative electrode tab of Example 1 into a liquid battery:

[0131] 1. Preparation of the positive electrode tab

[0132] Mix the positive electrode active material LiNi 0.8 Co 0.1 Mn 0.1 O 2 , the conductive agent Super P, and the binder polyvinylidene fluoride (PVDF) in N-methylpyrrolidone (NMP) to make a positive electrode slurry. The solid content in the positive electrode slurry is 50 wt%, and the mass ratio of LiNi 0.8 Co 0.1 Mn 0.1 O 2 , Super P, and PVDF in the solid components is 8:1:1. Coating the positive electrode slurry on the upper and lower surfaces of the current collector aluminum foil, drying at 85 °C, then performing cold pressing, followed by trimming, slicing, and striping, and finally drying in a vacuum at 85 °C for 4 h to make the positive electrode tab.

[0133] 2. Preparation of the electrolyte

[0134] In an argon atmosphere glove box (H 2 O < 0.1 ppm, O 2(<0.1 ppm), dissolve the fully dried electrolyte salt LiTFSI in a mixed solvent (the mixed solvent includes 1,3-dioxolane (DOL) and 1,2-dimethoxyethane (DME), and 1,3-dioxolane (DOL) and 1,2-dimethoxyethane (DME) are mixed in a volume ratio of 50:50). After mixing evenly, an electrolyte solution with a concentration of 1 mol / L is obtained.

[0135] 3. Separator

[0136] Use a 16-μm polyethylene film as the separator.

[0137] 4. Preparation of lithium metal battery

[0138] Stack the positive electrode plate, separator, and the negative electrode plate of Example 1 in sequence, with the separator in the middle of the positive and negative electrode plates to isolate the positive and negative electrodes, wind to obtain a bare battery core, weld the electrode tabs, place the bare battery core in the outer package, inject the above-prepared electrolyte into the dried battery core, and perform encapsulation, static placement, formation, shaping, capacity testing, etc. to complete the preparation of the lithium metal battery.

[0139] Characterize the cycle performance of the lithium metal battery obtained from the negative electrode plate of Example 1.

[0140] Cycle performance test method of lithium metal battery

[0141] Under the condition of 25°C ± 2°C, charge at a constant current of 0.2C. When the battery voltage reaches 4.2V, switch to constant voltage charging and stop charging when the charging current drops to 0.05C. After charging, let it stand for 30 minutes, and discharge at a current of 0.3C until the voltage reaches 2.6V. After cycling 50 times according to the above charge-discharge process, disassemble the battery and perform scanning electron microscope (SEM) testing on the negative electrode plate of Example 1.

[0142] It can be seen from the obtained SEM images that the surface of the negative electrode plate of Example 1 is uniform and relatively flat, and no obvious growth of lithium dendrites is observed.

[0143] It can be seen from Example 1 that using the negative electrode plate of the present invention can improve the interfacial problems of metallic lithium in the application of secondary batteries, avoid problems such as continuous thickening of the SEI film, continuous growth of lithium dendrites, dead lithium, and lithium dendrites piercing the separator, thereby being beneficial to improving the cycle stability of the lithium metal battery using this negative electrode plate.

[0144] In the description of this specification, the description referring to terms such as "one embodiment", "some embodiments", "examples", "specific examples", or "some examples", etc. means that the specific features, structures, materials, or characteristics described in connection 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 may be combined in any one or more embodiments or examples in a suitable manner. In addition, without contradiction, those skilled in the art can combine and combine the different embodiments or examples described in this specification and the features of different embodiments or examples.

[0145] Although the embodiments of the present invention have been shown and described above, it can be understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those of ordinary skill in the art can make changes, modifications, substitutions, and variations to the above embodiments within the scope of the present invention.

Claims

1. A negative electrode plate, characterized in that, it comprises: a current collector, the current collector comprising opposite first and second sides; a first active material layer and a first artificial SEI layer, the first active material layer and the first artificial SEI layer are sequentially arranged on the first side of the current collector along the 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 plate according to claim 1, characterized in that, the current collector is a composite current collector.

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

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

5. The negative electrode plate according to claim 4, characterized in that, it further comprises a second active material layer, the second active material layer is provided on the second side of the current collector, and the second active material layer comprises a metallic lithium alloy.

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

7. The negative electrode plate according to claim 6, characterized in that, it further comprises a second artificial SEI layer, the second artificial SEI layer is provided on the side of the second active material layer away from the current collector, and the second artificial SEI layer comprises a lithium compound.

8. The negative electrode plate according to claim 4, characterized in that, it further comprises a third active material layer and a third artificial SEI layer, the third active material layer and the third artificial SEI layer are sequentially arranged on the second side of the current collector along the direction away from the current collector, the third active material layer comprises metallic lithium, and the third artificial SEI layer comprises a lithium compound and a metallic lithium alloy.

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

10. The negative electrode plate according to claim 4, characterized in that, it further comprises a fourth active material layer and a fifth active material layer, the fourth active material layer and the fifth active material layer are sequentially arranged on the second side of the current collector along the direction away from the current collector, the fourth active material layer comprises metallic lithium, and the fifth active material layer comprises a metallic lithium alloy.

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

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

13. The negative electrode plate according to claim 1 or 5 or 8 or 10, It is characterized in that the lithium metal alloy includes an alloy formed by lithium metal 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, It is characterized in that the lithium metal alloy in the first artificial SEI layer includes Li-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, and the molar ratio of the lithium compound in the first artificial SEI layer to Li-M is (0.1-10):

1.

15. A method for preparing a negative electrode sheet, It is characterized in that including: providing a current collector, the current collector including opposite first and second sides; forming a first active material layer on the first side of the current collector, the first active material layer including lithium metal; forming a first artificial SEI layer on the side of the first active material layer away from the current collector, the first artificial SEI layer including a lithium compound and a lithium metal alloy.

16. The method according to claim 15, It is characterized in that further including: forming a second active material layer on the second side of the current collector, the second active material layer including a lithium metal alloy; forming a second artificial SEI layer on the side of the second active material layer away from the current collector, the second artificial SEI layer including a lithium compound.

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

18. A lithium metal battery, It is characterized in that it includes the negative electrode sheet according to any one of claims 1-14 or the negative electrode sheet obtained by using the method according to any one of claims 15-17.

19. The lithium metal battery according to claim 18, It is characterized in that the lithium metal battery includes a liquid battery, a semi-solid battery and a solid-state battery.

20. The lithium metal battery according to claim 19, It is 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, It is characterized in that 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 trifluoromethylsulfonyl-n-perfluorobutanesulfonylimide, lithium fluorosulfonyl-n-perfluorobutanesulfonylimide, lithium bis(oxalato)borate and lithium tris(trifluoromethylsulfonyl)methyl.

22. The lithium metal battery according to claim 20 or 21, It is 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, dimethoxydimethane, 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 the content of water and HF, 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 a 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 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 it includes: providing a negative electrode plate, the negative electrode plate includes a current collector having opposite first and second sides, a first active material layer is provided on the first side of the current collector, the first active material layer includes metallic lithium, and a first metal compound layer is 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 it so that the first metal compound layer forms a first artificial SEI layer during the charging process of the battery, and the first artificial SEI layer includes a lithium compound and a metallic lithium alloy, wherein the first metal compound layer includes a compound of at least one of halogen, oxygen element, nitrogen element, sulfur element, and phosphorus element 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 it includes: providing a negative electrode plate, the negative electrode plate includes a current collector having opposite first and second sides, a first active material layer is provided on the first side of the current collector, the first active material layer includes 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, and the second active material layer includes a metallic lithium alloy; assembling the negative electrode plate into a battery and charging it so that the first metal compound layer in-situ forms a first artificial SEI layer during the charging process of the battery, and the first artificial SEI layer includes a lithium compound and a metallic lithium alloy, wherein the first metal compound layer includes a compound of at least one of halogen, oxygen element, nitrogen element, sulfur element, and phosphorus element 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 it includes: A negative electrode plate is provided. The negative electrode plate includes a current collector having opposite first and second sides. A first active material layer is provided on the first side of the current collector. The first active material layer includes metallic lithium. A first metal compound layer is provided on a side of the first active material layer away from the current collector. A second active material layer is provided on the second side of the current collector. The second active material layer includes 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. The second artificial SEI layer includes a lithium compound; The negative electrode plate is assembled into a battery and charged to form a first artificial SEI layer in-situ on the first metal compound layer during the charging process of the battery. The first artificial SEI layer includes a lithium compound and a metallic lithium alloy. Wherein, the first metal compound layer includes a compound of at least one of halogen, oxygen element, nitrogen element, sulfur element and phosphorus element and M. 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, comprising: providing a negative electrode plate, the negative electrode plate includes a current collector having opposite first and second sides, a first active material layer is provided on the first side of the current collector, the first active material layer includes metallic lithium, a first metal compound layer is provided on a side of 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 a side of 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 metal compound layer forms a first artificial SEI layer in-situ during the charging process of the battery, and the second metal compound layer forms a third artificial SEI layer in-situ during the charging process of the battery. The first artificial SEI layer and the third artificial SEI layer each independently include a lithium compound and a metallic lithium alloy. Wherein, the first metal compound layer and the second metal compound layer each independently include a compound of at least one of halogen, oxygen element, nitrogen element, sulfur element and phosphorus element and M. 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, comprising: providing a negative electrode plate, the negative electrode plate includes a current collector having opposite first and second sides, a first active material layer is provided on the first side of the current collector, the first active material layer includes metallic lithium, a first metal compound layer is provided on a side of the first active material layer 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 includes metallic lithium, and a fifth active material layer is provided on a side of the fourth active material layer away from the current collector. The fifth active material layer includes a metallic lithium alloy; Assemble the negative electrode sheet into a battery and charge it, so that the first metal compound layer forms a first artificial SEI layer in situ during the charging process of the battery. 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 element, nitrogen element, sulfur element and phosphorus element and M. 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 It includes the lithium metal battery described in any one of claims 18-24 or the lithium metal battery obtained by the method described in any one of claims 25-29.

Images