Lithium negative electrode and preparation method thereof, battery and electric equipment

Abstract

The invention discloses a lithium negative electrode, a preparation method, a battery and electric equipment. The lithium negative electrode comprises lithium metal and functional layers arranged on at least one surface of the lithium metal, wherein the functional layers comprise a first functional layer and a second functional layer; wherein the first functional layer comprises inorganic nanowires, and the inorganic nanowires are distributed on the surface of lithium metal to form an inorganic framework; the second functional layer comprises lithium-loving metal particles, lithium alloy and lithium fluoride, and the lithium-loving metal particles, the lithium alloy and the lithium fluoride are distributed inside and / or on the surface of the inorganic framework. According to the lithium negative electrode, the lithium ion transmission rate can be effectively increased, the effect of protecting the lithium metal interface structure is achieved, and then the coulombic efficiency and the cycle life of the battery are improved.

Description

TECHNICAL FIELD

[0001] The present application generally relates to the field of new energy technology, and in particular to a lithium negative electrode and a preparation method thereof, a battery and an electric device. BACKGROUND

[0002] Replacing the traditional graphite negative electrode (372 mAh g-1) with lithium metal (3860 mAh g-1) of high specific capacity can significantly improve the energy density of the battery. However, due to the intrinsic characteristics of the lithium negative electrode, the high reducibility and the characteristics of unlimited volume expansion of lithium metal can cause side reactions between the lithium negative electrode and the electrolyte and the problem of lithium dendrite, thereby causing the cycle performance and the coulombic efficiency of the battery to decrease, and causing a safety hazard due to the short circuit of the battery caused by the puncture of the separator. Therefore, how to improve the lithium metal negative electrode has very important significance for improving the performance of the battery. SUMMARY

[0003] In view of the above defects or deficiencies in the prior art, it is desirable to provide a lithium negative electrode and a preparation method thereof, a battery and an electric device, at least one surface of the lithium metal includes a functional layer, the inorganic nanowires in the first functional layer form an inorganic skeleton, which is conducive to improving the wettability of the surface of the lithium metal, the lithiumophilic metal particles, lithium alloy and lithium fluoride in the second functional layer can effectively improve the lithium ion transmission rate and play a role in protecting the interface structure of the lithium metal, thereby improving the coulombic efficiency and cycle life of the battery.

[0004] In a first aspect, the present application provides a lithium negative electrode, comprising: lithium metal and a functional layer arranged on at least one surface of the lithium metal, the functional layer comprising a first functional layer and a second functional layer;

[0005] The first functional layer comprises inorganic nanowires, and the inorganic nanowires are distributed on the surface of the lithium metal to form an inorganic skeleton;

[0006] The second functional layer comprises lithiumophilic metal particles, lithium alloy and lithium fluoride, and the lithiumophilic metal particles, lithium alloy and lithium fluoride are distributed inside and / or on the surface of the inorganic skeleton.

[0007] As an optional solution, the inorganic nanowires comprise at least one of carbon nanotubes, oxides, sulfides, nitrides and inorganic solid-state electrolytes; and the inorganic nanowires have a certain aspect ratio;

[0008] The carbon nanotubes comprise single-walled carbon nanotubes or multi-walled carbon nanotubes;

[0009] The oxides comprise at least one of lithium oxide, boron oxide, magnesium oxide, aluminum oxide, silicon oxide, titanium oxide, vanadium oxide, chromium oxide, manganese oxide, iron oxide, cobalt oxide, nickel oxide, copper oxide, zinc oxide, gallium oxide, tin oxide, molybdenum oxide, niobium oxide and bismuth oxide;

[0010] The sulfides include at least one of iron sulfide, cobalt sulfide, nickel sulfide, copper sulfide, zinc sulfide, tin sulfide, bismuth sulfide, tungsten sulfide, and molybdenum sulfide.

[0011] The nitrides include at least one of boron nitride, magnesium nitride, aluminum nitride, silicon nitride, titanium nitride, vanadium nitride, chromium nitride, manganese nitride, iron nitride, cobalt nitride, nickel nitride, copper nitride, zinc nitride, gallium nitride, tin nitride, molybdenum nitride, niobium nitride, and bismuth nitride.

[0012] The solid electrolytes include at least one of LLZO, LLZTO, LLZAO, LLZNO, LLZGO, LLTO, LLTO, LTP, LATP, and LAGP.

[0013] As an optional solution, the aspect ratio of the inorganic nanowire is 10-10000; preferably, the aspect ratio of the inorganic nanowire is 2000-5000.

[0014] As an optional solution, the lithiumophilic metal includes silver metal particles or magnesium metal particles after being lithiated.

[0015] As an optional solution, the functional layer further includes an organic polymer layer, the organic polymer layer is formed on the inorganic framework, and forms a three-dimensional framework with the inorganic framework.

[0016] As an optional solution, the organic polymer layer includes at least one of PVDF, PEO, PU, PMMA, and PAN.

[0017] In a second aspect, the present application provides a preparation method of a lithium negative electrode, the lithium negative electrode including lithium metal and a functional layer arranged on at least one surface of the lithium metal, the functional layer including a first functional layer and a second functional layer, and specifically including the following steps:

[0018] forming the first functional layer on the surface of the lithium metal to obtain a first substrate; the first functional layer includes inorganic nanowires, and the inorganic nanowires are distributed on the surface of the lithium metal to form an inorganic framework,

[0019] forming the second functional layer in the interior and / or on the surface of the inorganic framework to obtain the lithium negative electrode; the second functional layer includes lithiumophilic metal particles, lithium alloy, and lithium fluoride.

[0020] As an optional solution, forming the first functional layer on the surface of the lithium metal includes:

[0021] mixing the inorganic nanowires and the dispersant to obtain a first mixed solution;

[0022] spraying the first mixed solution to the surface of the lithium metal and reacting to form the first functional layer to obtain the first substrate.

[0023] As an optional solution, in the process of mixing the inorganic nanowire and the dispersant to obtain the first mixed solution, the dispersant comprises a first dispersant and a second dispersant, and the first dispersant comprises at least one of petroleum ether, 1,3-dioxolane, tetrahydrofuran, ethylene glycol dimethyl ether, and dimethyl carbonate.

[0024] The second dispersant comprises polyvinylpyrrolidone and / or polyethylene glycol.

[0025] As an optional solution, in the process of mixing the inorganic nanowire and the dispersant to obtain the first mixed solution, the mass ratio of the inorganic nanowire to the second dispersant is (2-10):1.

[0026] As an optional solution, in the process of spraying the first mixed solution to the surface of the lithium metal and reacting to form the first functional layer, the spraying mode comprises one of air spraying, high-pressure airless spraying, and ultrasonic spraying.

[0027] The spraying amount of the spraying mode is 0.01L / min -1 -1L / min -1 The reaction temperature is 10-95℃.

[0028] As an optional solution, forming the second functional layer inside and / or on the surface of the inorganic framework comprises:

[0029] Dispersing the solid-solution type metal fluoride and the non-solid-solution type metal fluoride in a solvent to obtain a second mixed solution;

[0030] Spraying the second mixed solution onto the first substrate to form lithiumophilic metal particles, lithium alloy, and lithium fluoride inside and on the surface of the inorganic framework; wherein the solid-solution type metal element comprises a lithiumophilic metal element.

[0031] As an optional solution, in the process of dispersing the solid-solution type metal fluoride and the non-solid-solution type metal fluoride in a solvent to obtain a second mixed solution, the solid-solution type metal fluoride comprises one of silver hexafluorophosphate, silver hexafluoroantimonate, silver pentafluoropropionate, silver tetrafluoroborate, silver trifluoromethanesulfonate, silver trifluoromethanethiol, silver bistrifluoromethanesulfonylimide, silver methane sulfonate, magnesium trifluoromethanesulfonate, and magnesium bistrifluoromethanesulfonylimide.

[0032] The non-solid-solution type metal fluoride comprises one of hexafluorophosphate, potassium hexafluorotitanate, sodium hexafluorotitanate, potassium hexafluorozirconate, sodium hexafluorozirconate, potassium hexafluorotantalate, sodium hexafluorotantalate, potassium hexafluoroantimonate, sodium hexafluoroantimonate, a trifluoromethanesulfonate of a first metal, and a tetrafluoroborate of a second metal; wherein the first metal comprises potassium, sodium, tin, aluminum, copper, zinc, scandium, bismuth, indium, hafnium, or ytterbium; and the second metal comprises potassium, sodium, stannous, rubidium, calcium, iron, nickel, copper, zinc, or lead.

[0033] The solvent includes at least one of dimethyl carbonate, ethylene glycol dimethyl ether, triethylene glycol divinyl ether, petroleum ether, dimethyl sulfoxide, N,N-dimethylformamide, N,N-dimethylacetamide and N-methyl pyrrolidone;

[0034] The concentration of the second mixed solution is 0.1 mol / L -1 -3 mol / L -1 .

[0035] As an optional solution, the second mixed solution is sprayed onto the first substrate, and the spraying mode includes one of air spraying, high-pressure airless spraying and ultrasonic spraying;

[0036] The spraying amount of the spraying mode is 0.01 L / min -1 -1 L / min -1 ; preferably, the spraying amount of the spraying mode is 0.2 L / min -1 -0.4 L / min -1 .

[0037] As an optional solution, after the second functional layer is formed inside and on the surface of the inorganic framework, the preparation method further includes:

[0038] The epoxy ether is sprayed on the second functional layer, and the inorganic framework, the lithium-philic metal particles, the lithium alloy and the lithium fluoride are immersed, and an organic polymer layer is formed by reaction;

[0039] As an optional solution, the epoxy ether includes 1,3-dioxolane and 1,3-dioxane;

[0040] As an optional solution, the spraying amount of the spraying mode is 0.01 L / min -1 -1 L / min -1 , and the reaction temperature is 0-100℃;

[0041] The spraying amount of the spraying mode is 0.05 L / min -1 -0.2 L / min -1 , and the reaction temperature is 20-50℃.

[0042] In a third aspect, the present application provides a battery including the lithium negative electrode of the first aspect or the lithium negative electrode prepared according to the preparation method of the second aspect.

[0043] The lithium negative electrode provided by the application forms a first functional layer and a second functional layer on the surface of lithium metal, the first functional layer comprises inorganic nanowires, the inorganic nanowires are distributed on the surface of lithium metal to form an inorganic framework, the second functional layer comprises lithiumophilic metal particles, lithium alloy and lithium fluoride, the lithiumophilic metal particles, the lithium alloy and the lithium fluoride are distributed inside and / or on the surface of the inorganic framework; wherein the inorganic nanowires distributed on the surface of lithium metal form an inorganic framework, which is beneficial to improve the wettability of the surface of lithium metal and reduce the contact angle; the lithiumophilic metal particles in the second functional layer have the characteristics of dissolving Li, and when lithium ions are deposited on the surface of the lithium metal negative electrode, the lithiumophilic metal particles can be dissolved into the lithiumophilic metal element to form an alloy solid solution, so as to avoid the problem of dendrite nucleation caused by the too fast local deposition of lithium ions, and further avoid the formation of lithium dendrites; the lithium fluoride can prevent the transmission of electrons into the electrolyte, so as to alleviate the problem of lithium dendrite growth in the electrolyte; the lithium alloy can improve the diffusion rate of lithium ions, so as to further alleviate the generation of lithium dendrites. The lithium negative electrode of the application can improve the coulomb efficiency of the battery and improve the cycle life of the battery. BRIEF DESCRIPTION OF DRAWINGS

[0044] Other features, objects and advantages of the application will become more apparent from the following detailed description of non-limiting embodiments, made with reference to the accompanying drawings:

[0045] Figure 1 The processing flow diagram of the lithium negative electrode of the embodiment of the application is shown in the figure;

[0046] Figure 2 The battery performance test results of Example 1 of the application are shown in the figure.

[0047] In the figure, 1, lithium metal, 2, first functional layer, 3, second functional layer, 4, organic polymer layer, 5, fourth substrate, 6, flexible solid-state electrolyte layer. DETAILED DESCRIPTION

[0048] The application will be further described in detail below with reference to the embodiments. It can be understood that the specific embodiments described herein are only used to explain the related application, and not to limit the application.

[0049] It should be noted that the embodiments in the application and the features in the embodiments can be combined with each other without conflict. The application will be described in detail below with reference to the embodiments.

[0050] Solid-state electrolytes are generally considered to have a higher modulus and are therefore believed to inhibit lithium dendrites, but poor interface contact in solid-state batteries can still cause lithium dendrite problems. To address the problem of lithium dendrites in solid-state and liquid-state systems, the improvement method in the related art includes: artificially coating a flexible interface layer. Artificially coating an interface layer by coating a flexible polymer interface layer on the surface of lithium metal can effectively improve the contact performance of lithium metal and solid-state electrolyte, and can also isolate the contact between electrolyte and lithium metal to some extent, thereby protecting the lithium metal interface and improving the interface stability of the solid-state battery. However, pure polymer solid-state electrolytes have low ionic conductivity, low mechanical strength, and poor coating uniformity, which cannot meet the requirements of high uniformity for large-scale cell preparation.

[0051] Based on the above problems, in a first aspect, embodiments of the present application provide a lithium negative electrode, comprising: lithium metal and a functional layer arranged on at least one surface of the lithium metal, the functional layer comprising a first functional layer and a second functional layer.

[0052] The first functional layer comprises inorganic nanowires, and the inorganic nanowires are distributed on the surface of the lithium metal to form an inorganic skeleton.

[0053] The second functional layer comprises lithiumophilic metal particles, lithium alloy and lithium fluoride, and the lithiumophilic metal particles, lithium alloy and lithium fluoride are distributed inside and / or on the surface of the inorganic skeleton.

[0054] The first functional layer can be understood as an interface wetting layer, which is mainly used to improve the wettability of the lithium metal interface and reduce the contact angle. The second functional layer can be understood as an active transition layer and a lithium metal solid-solution-non-solid-solution passivation layer, which is mainly used to improve the transmission rate of lithium ions and inhibit the growth of lithium dendrites.

[0055] The lithium negative electrode of the embodiments of the present application solves the problems of low ionic conductivity, low mechanical strength and poor uniformity of the existing technology of coating the surface of lithium metal with pure polymer solid-state electrolyte alone. The lithium negative electrode of the embodiments of the present application forms a first functional layer and a second functional layer on the surface of lithium metal, the first functional layer includes inorganic nanowires, and the inorganic nanowires are distributed on the surface of lithium metal to form an inorganic framework, the second functional layer includes lithiumophilic metal particles, lithium alloy and lithium fluoride, and the lithiumophilic metal particles, lithium alloy and lithium fluoride are distributed inside and / or on the surface of the inorganic framework; wherein the inorganic nanowires distributed on the surface of lithium metal form an inorganic framework, which is beneficial to improve the wettability of the surface of lithium metal and reduce the contact angle; the lithiumophilic metal particles in the second functional layer have the characteristics of dissolving Li, and when lithium ions are deposited on the surface of the lithium metal negative electrode, they can be dissolved into lithiumophilic metal elements to form an alloy solid solution, so as to avoid the problem of dendrite nucleation caused by the local deposition of lithium ions too fast, and further avoid the formation of lithium dendrites; lithium fluoride can prevent electrons from entering the electrolyte, so as to alleviate the problem of lithium dendrite growth in the electrolyte; lithium alloy can improve the diffusion rate of lithium ions, thereby further alleviating the generation of lithium dendrites. The lithium negative electrode of the embodiments of the present application can improve the coulombic efficiency of the battery and improve the cycle life of the battery.

[0056] Further, in some embodiments, the inorganic nanowires include at least one of carbon nanotubes, oxides, sulfides, nitrides and inorganic solid-state electrolytes;

[0057] The carbon nanotubes include single-walled carbon nanotubes or multi-walled carbon nanotubes;

[0058] The oxides include at least one of lithium oxide, boron oxide, magnesium oxide, aluminum oxide, silicon oxide, titanium oxide, vanadium oxide, chromium oxide, manganese oxide, iron oxide, cobalt oxide, nickel oxide, copper oxide, zinc oxide, gallium oxide, tin oxide, molybdenum oxide, niobium oxide and bismuth oxide;

[0059] The sulfides include at least one of iron sulfide, cobalt sulfide, nickel sulfide, copper sulfide, zinc sulfide, tin sulfide, bismuth sulfide, tungsten sulfide and molybdenum sulfide;

[0060] The nitrides include at least one of boron nitride, magnesium nitride, aluminum nitride, silicon nitride, titanium nitride, vanadium nitride, chromium nitride, manganese nitride, iron nitride, cobalt nitride, nickel nitride, copper nitride, zinc nitride, gallium nitride, tin nitride, molybdenum nitride, niobium nitride and bismuth nitride;

[0061] The solid-state electrolyte includes at least one of LLZO, LLZTO, LLZAO, LLZNO, LLZGO, LLTO, LLTO, LTP, LATP and LAGP.

[0062] In preferred embodiments, the lithiumophilic metal includes silver metal particles or magnesium metal particles after being lithiated.

[0063] In the embodiment, silver and magnesium are lithium solid solution type metal elements, and the silver metal particles or magnesium metal particles after lithiation have high lithium ion diffusion capacity, which is beneficial to the rapid migration of lithium ions at the interface, and can avoid the problem of lithium dendrites caused by the rapid deposition of lithium ions. In addition, the silver metal particles and magnesium metal particles can also migrate to the inside of the lithium metal negative electrode matrix, thereby improving the overall performance of the lithium negative electrode.

[0064] As an implementable manner, the functional layer further comprises an organic polymer layer, and the organic polymer layer is formed on the inorganic framework and forms a three-dimensional framework with the inorganic framework.

[0065] In a preferred embodiment, the organic polymer layer comprises at least one of PVDF, PEO, PU, PMMA and PAN.

[0066] In the embodiment, the organic polymer layer is mainly a polymer formed by ring-opening of an ether, and the high specific area of the inorganic framework is beneficial to adsorbing the ether and inhibiting the volatilization of the ether, thereby ensuring the effective formation of the organic polymer layer on the inorganic framework, obtaining an organic-inorganic three-dimensional framework layer, and further effectively improving the mechanical strength of the functional layer, preventing the structural degradation of the functional layer during the assembly and operation of the battery, and the three-dimensional framework formed by the organic polymer layer and the inorganic framework is also beneficial to the diffusion of lithium ions and provides a channel and additional space for lithium metal deposition.

[0067] In some embodiments, the lithium negative electrode further comprises a flexible solid-state electrolyte layer, and the flexible solid-state electrolyte layer is coated on the surface of the functional layer away from the lithium metal.

[0068] In the embodiment, the solid-state electrolyte is transferred on the surface of the functional layer away from the lithium metal, which is beneficial to further improving the contact performance of the solid-state electrolyte and the lithium metal.

[0069] In some embodiments, the thickness of the solid-state electrolyte layer is 2 μm-100 μm.

[0070] Specifically, the thickness of the flexible solid-state electrolyte layer can be, but is not limited to, 2 μm, 20 μm, 500 μm, 800 μm or 100 μm, etc. When the thickness of the solid-state electrolyte layer is less than 2 μm, the flexible solid-state electrolyte layer is too thin to reliably protect the lithium metal interface; when the thickness of the flexible solid-state electrolyte layer is greater than 100 μm, the solid-state electrolyte layer is too thick, which may prolong the transmission rate of lithium ions, thereby affecting the performance of the battery.

[0071] In some embodiments, the flexible solid-state electrolyte layer comprises, in terms of mass percentage, 25%-50% of a polymer, 25%-50% of a lithium salt and 0-50% of a reinforcing phase.

[0072] In some embodiments, the polymer comprises at least one of PVDF, PEO, PU, PMMA and PAN.

[0073] The lithium salt includes at least one of lithium bistrifluoromethylsulfonylimide, lithium trifluoromethylsulfonylimide, lithium bisfluorosulfonimide, lithium bisfluorosulfonyl oxide borate, lithium tetrafluoroborate, lithium hexafluorophosphate, lithium bisoxalate borate and lithium difluorophosphate;

[0074] The reinforcing phase includes at least one of oxides, sulfides, nitrides and inorganic solid-state electrolytes; wherein the oxides, sulfides, nitrides and inorganic solid-state electrolytes are in any form;

[0075] The oxides include at least one of lithium oxide, boron oxide, magnesium oxide, aluminum oxide, silicon oxide, titanium oxide, vanadium oxide, chromium oxide, manganese oxide, iron oxide, cobalt oxide, nickel oxide, copper oxide, zinc oxide, gallium oxide, tin oxide, molybdenum oxide, niobium oxide and bismuth oxide;

[0076] The sulfides include at least one of iron sulfide, cobalt sulfide, nickel sulfide, copper sulfide, zinc sulfide, tin sulfide, bismuth sulfide, tungsten sulfide and molybdenum sulfide;

[0077] The nitrides include at least one of boron nitride, magnesium nitride, aluminum nitride, silicon nitride, titanium nitride, vanadium nitride, chromium nitride, manganese nitride, iron nitride, cobalt nitride, nickel nitride, copper nitride, zinc nitride, gallium nitride, tin nitride, molybdenum nitride, niobium nitride and bismuth nitride;

[0078] The solid-state electrolyte includes at least one of LLZO, LLZTO, LLZAO, LLZNO, LLZGO, LLTO, LLTO, LTP, LATP and LAGP.

[0079] Further, in the preferred embodiment, the flexible solid-state electrolyte layer includes 40% of the polymer, 40% of the lithium salt and 20% of the reinforcing phase in terms of mass percentage; wherein the polymer can be PVDF-HFP, the lithium salt can be a composite salt of lithium bistrifluoromethylsulfonylimide and lithium bisfluorosulfonyl oxide borate, and the reinforcing phase can be LLZO solid-state electrolyte powder.

[0080] The flexible solid-state electrolyte of the embodiment has good performance and can reliably improve the performance of the lithium metal negative electrode battery.

[0081] In some embodiments, the particle size of the reinforcing phase is 10 nm-1000 nm.

[0082] The particle size of the reinforcing phase of the embodiment has the effect of improving the strength and electrochemical performance of the solid-state electrolyte.

[0083] In the preferred embodiment, the particle size of the reinforcing phase is 50 nm-400 nm.

[0084] In a second aspect, embodiments of the present application provide a method for preparing a lithium negative electrode, the lithium negative electrode comprising lithium metal and a functional layer arranged on at least one surface of the lithium metal, the functional layer comprising a first functional layer and a second functional layer, and the method comprising the following steps:

[0085] S1, forming the first functional layer on the surface of the lithium metal to obtain a first substrate; the first functional layer comprises inorganic nanowires, and the inorganic nanowires are distributed on the surface of the lithium metal to form an inorganic framework,

[0086] It can be understood that the inorganic nanowires can be prepared by using a material with a fibrous structure, uniformly dispersing the material with the fibrous structure on the surface of the lithium metal to obtain the first functional layer, or selecting a precursor material to prepare the inorganic nanowires by an in-situ growth process, for example, but not limited to, a hydrothermal synthesis method, a chemical vapor deposition method, etc.

[0087] S2, forming the second functional layer on the inside and / or surface of the inorganic framework to obtain the lithium negative electrode; the second functional layer comprises lithiumophilic metal particles, lithium alloy and lithium fluoride.

[0088] Similarly, the second functional layer can directly use metal fluorides and lithiumophilic metal salts to obtain the lithiumophilic metal particles, the lithium alloy and the lithium fluoride on the lithium metal by a dispersion method, or the second functional layer can also use a precursor material to obtain the lithiumophilic metal particles, the lithium alloy and the lithium fluoride on the lithium metal by an in-situ growth method.

[0089] The method for preparing the lithium negative electrode according to the embodiments of the present application is simple to operate and easy to implement, and the lithium negative electrode prepared by the method has the first functional layer and the second functional layer formed on the surface of the lithium metal, wherein the inorganic nanowires of the first functional layer are distributed on the surface of the lithium metal to form the inorganic framework, which is beneficial to improve the wettability of the surface of the lithium metal and reduce the contact angle; the lithiumophilic metal particles in the second functional layer have the characteristics of dissolving Li, and can be dissolved into the lithiumophilic metal element to form an alloy solid solution when lithium ions are deposited on the surface of the lithium metal negative electrode, so as to avoid the problem of dendrite nucleation caused by the too fast local deposition of lithium ions, and further avoid the formation of lithium dendrites; the lithium fluoride can prevent the transmission of electrons into the electrolyte, so as to alleviate the problem of the growth of lithium dendrites in the electrolyte; the lithium alloy can improve the diffusion rate of lithium ions, thereby further alleviating the generation of lithium dendrites. The lithium negative electrode can improve the coulombic efficiency of the battery and prolong the cycle life of the battery.

[0090] In some embodiments, step S1 of forming the first functional layer on the surface of the lithium metal comprises:

[0091] mixing the inorganic nanowires and the dispersant to obtain a first mixed solution;

[0092] spraying the first mixed solution to the surface of the lithium metal and reacting to form the first functional layer to obtain the first substrate.

[0093] It can be understood that the main role of the dispersant is to uniformly disperse the inorganic nanowire material and dissolve part of the soluble elements, thereby facilitating the preparation of the first functional layer.

[0094] The preparation process of the first functional layer of the embodiment is simple in operation, and the spraying manner uniformly disperses the inorganic nanowires on the surface of the lithium metal to form an inorganic skeleton.

[0095] In some embodiments, in the process of mixing the inorganic nanowires and the dispersant to obtain the first mixed solution, the dispersant includes a first dispersant and a second dispersant, the first dispersant includes at least one of petroleum ether, 1,3-dioxolane, tetrahydrofuran, ethylene glycol dimethyl ether, and dimethyl carbonate;

[0096] The second dispersant includes polyvinylpyrrolidone and / or polyethylene glycol.

[0097] Specifically, the first dispersant is mainly used for dispersing the inorganic nanowires, and the second dispersant mainly serves as an organic solvent.

[0098] In preferred embodiments, in the process of mixing the inorganic nanowires and the dispersant to obtain the first mixed solution, the mass ratio of the inorganic nanowires to the second dispersant is (2-10):1.

[0099] Specifically, the mass ratio of the inorganic nanowires to the dispersant can be, but is not limited to, 2:1, 3:1, 5:1, 7:1, or 10:1. When the mass ratio of the inorganic nanowires to the dispersant is less than 2:1, the mass of the inorganic nanowires is too low, which leads to the failure of reliably forming an inorganic skeleton on the surface of the lithium metal; when the mass ratio of the inorganic nanowires to the dispersant is higher than 10:1, the mass of the inorganic nanowires is too high, which can lead to the failure of uniformly dispersing the inorganic nanowires, thereby causing the agglomeration of the inorganic nanowires.

[0100] The mass ratio of the inorganic nanowires to the dispersant in the embodiment is advantageous to uniformly dispersing the inorganic nanowires, reliably forming an inorganic skeleton, and improving the wettability of the surface of the lithium metal.

[0101] In some embodiments, the aspect ratio of the inorganic nanowires is 10-10000.

[0102] In preferred embodiments, the aspect ratio of the inorganic nanowires is 2000-5000.

[0103] Specifically, the aspect ratio of the inorganic nanowires can be, but is not limited to, 2000, 2500, 3000, 4000, or 5000, etc.

[0104] The aspect ratio of the inorganic nanowires in the embodiment has the advantages of increasing the specific surface area of the composite layer, enhancing the physical entanglement between the inorganic nanowires, and improving the liquid retention capacity and the mechanical strength of the coating layer.

[0105] In some embodiments, the spraying method includes one of air spraying, high-pressure airless spraying, and ultrasonic spraying during the process of spraying the first mixed solution to the surface of the lithium metal and reacting to form the first functional layer.

[0106] The spraying amount of the spraying method is 0.01 L / min-1 L / min, and the reaction temperature is 10℃-95℃.

[0107] The spraying amount can be, but is not limited to, 0.01 L / min, 0.03 L / min, 0.05 L / min, 0.07 L / min, or 1 L / min, etc. When the spraying amount is lower than 0.01 L / min, the first functional layer formed is too thin to form a reliable inorganic framework, and it may also increase solvent consumption. When the spraying amount is higher than 1 L / min, it may cause the agglomeration of inorganic nanowires, and the problem of uneven dispersion.

[0108] The reaction temperature can be, but is not limited to, 10℃, 30℃, 40℃, 50℃, 70℃, or 95℃.

[0109] The spraying amount of the present application is beneficial to the uniform dispersion of inorganic nanowires on the surface of lithium metal, and the reaction is stable at a lower temperature, which is safe to operate, and further beneficial to the formation of inorganic framework by inorganic nanowires on the surface of lithium metal, which can reliably improve the wettability of the surface of lithium metal.

[0110] In some embodiments, the second functional layer is formed inside and on the surface of the inorganic framework, including:

[0111] The solid-solution type metal fluoride and the non-solid-solution type metal fluoride are dispersed in a solvent to obtain a second mixed solution.

[0112] The second mixed solution is sprayed onto the first substrate to form lithiumophilic metal particles, lithium alloy, and lithium fluoride inside and on the surface of the inorganic framework; wherein the solid-solution type metal element includes a lithiumophilic metal element.

[0113] The present embodiment selects solid-solution type metal fluoride and non-solid-solution type metal fluoride as precursors, and forms lithiumophilic metal particles, lithium alloy, and lithium fluoride in situ inside and on the surface of the inorganic framework by spraying, which is simple and controllable in operation, and can reliably improve the transmission rate of lithium ions and alleviate the formation of lithium dendrites.

[0114] In some embodiments, the solid-solution type metal fluoride and the non-solid-solution type metal fluoride are dispersed in a solvent to obtain a second mixed solution, and the solid-solution type metal fluoride includes one of silver hexafluorophosphate, silver hexafluoroantimonate, silver pentafluoropropionate, silver tetrafluoroborate, silver trifluoromethanesulfonate, silver trifluoromethane thiol, silver bis-trifluoromethanesulfonylimide, silver methane sulfonate, magnesium triflate, and magnesium bis-trifluoromethanesulfonylimide.

[0115] The non-solid-solution metal fluoride includes one of trifluoromethanesulfonate of a first metal, potassium hexafluorophosphate, sodium hexafluorophosphate, potassium hexafluorotitanate, sodium hexafluorotitanate, potassium hexafluorozirconate, sodium hexafluorozirconate, potassium hexafluorotantalate, sodium hexafluorotantalate, potassium hexafluoroantimonate, sodium hexafluoroantimonate, and tetrafluoroborate of a second metal; wherein the first metal includes potassium, sodium, tin, aluminum, copper, zinc, scandium, bismuth, indium, hafnium, or ytterbium; and the second metal includes potassium, sodium, stannous, rubidium, calcium, iron, nickel, copper, zinc, or lead;

[0116] The solvent includes at least one of dimethyl carbonate, ethylene glycol dimethyl ether, triethylene glycol divinyl ether, petroleum ether, dimethyl sulfoxide, N,N-dimethylformamide, N,N-dimethylacetamide, and N-methylpyrrolidone;

[0117] The concentration of the second mixed solution is 0.1 mol / L -1 -3 mol / L -1 .

[0118] As a realizable manner, the second mixed solution is sprayed onto the first substrate, and the spraying manner includes one of air spraying, high-pressure airless spraying, and ultrasonic spraying;

[0119] The spraying amount of the spraying manner is 0.01 L / min-1 L / min.

[0120] Specifically, the spraying amount can be, but is not limited to, 0.01 L / min, 0.03 L / min, 0.05 L / min, 0.07 L / min, or 1 L / min, etc.; when the spraying amount is less than 0.01 L / min, the content of the lithiumophilic metal particles, lithium alloy, and lithium fluoride on the inorganic skeleton is less, which cannot reliably improve the battery performance of the lithium negative electrode, and is not conducive to the formation of the organic polymer layer; when the spraying amount is greater than 1 L / min, the reaction is insufficient, which affects the transmission of lithium ions.

[0121] The spraying amount in the embodiment is conducive to reliably forming the second functional layer, improving the transmission performance of lithium ions, and inhibiting lithium dendrite nucleation, and is conducive to forming the organic polymer layer.

[0122] In a preferred embodiment, the spraying amount of the spraying manner is 0.2 L / min-0.4 L / min.

[0123] As a realizable manner, after the second functional layer is formed on the inside and the surface of the inorganic skeleton, the preparation method further includes:

[0124] The epoxy ether is sprayed on the second functional layer, and the inorganic skeleton, lithiumophilic metal particles, lithium alloy, and lithium fluoride are immersed, to react to form an organic polymer layer.

[0125] The epoxy ether includes 1,3-dioxolane and 1,3-dioxane.

[0126] In the embodiment, the inorganic skeleton formed by the inorganic nanowires has a high specific surface area, so that the epoxy ether is more easily adsorbed on the inorganic skeleton, and under the action of the non-solid-solution metal fluoride, the cyclic ether is ring-opening polymerized to form an organic polymer layer, thereby forming an organic-inorganic three-dimensional skeleton, which can effectively improve the mechanical strength of the functional layer and prevent the functional layer from being damaged during the battery assembly process and operation.

[0127] In some embodiments, the epoxy ether is sprayed on the second functional layer, and the spraying mode includes one of air spraying, high-pressure airless spraying, and ultrasonic spraying, the spraying amount of the spraying mode is 0.01L / min to 1L / min, and the reaction temperature is 0-100℃.

[0128] The spraying amount can be, but is not limited to, 0.01L / min, 0.03L / min, 0.05L / min, 0.07L / min, or 1L / min, etc. When the spraying amount is lower than 0.01L / min, the organic polymer layer cannot be reliably formed. When the spraying amount is higher than 1L / min, the surface liquid is too much, which can cause the peeling of the fiber layer and uneven distribution of the coating.

[0129] The reaction temperature can be 10℃, 30℃, 50℃, 70℃, or 100℃.

[0130] The reaction temperature of the embodiment is beneficial to the ring-opening polymerization of the epoxy ether, and the spraying amount is beneficial to ensuring the formation of a reliable organic polymer layer while not affecting the transmission of lithium ions.

[0131] In a preferred embodiment, the spraying amount of the spraying mode is 0.05L / min to 0.2L / min, and the reaction temperature is 20℃ to 50℃.

[0132] As an implementable manner, after the epoxy ether is sprayed on the second functional layer and the inorganic skeleton, the lithiumophilic metal particles, the lithium alloy, and the lithium fluoride are immersed, and the organic polymer layer is formed by reaction, the preparation method further includes:

[0133] A flexible solid electrolyte layer is formed on the organic polymer layer, and a lithium negative electrode is obtained after rolling.

[0134] The embodiment is beneficial to forming a flexible solid electrolyte on the organic-inorganic three-dimensional skeleton, which can further improve the interface contact of the lithium negative electrode, thereby reliably improving the performance of the lithium metal negative electrode.

[0135] For example, the polymer, the reinforcing phase and the lithium salt described above are dissolved in a solvent to obtain a uniformly dispersed slurry, the flexible solid electrolyte slurry is obtained by using a casting method to cast the slurry on the surface of a release film, vacuum drying at 75°C for 24h to obtain a flexible solid electrolyte with a thickness of 20μm, then roll pressing with a pressure reduction of 10% of the total thickness of the functional layer and the flexible solid electrolyte layer to obtain a flexible solid electrolyte layer, and roll pressing the obtained flexible solid electrolyte layer with a lithium negative electrode and standing for 12h.

[0136] For example, as shown in FIG. 1, the lithium metal 1 is transported to a first spraying station, an inorganic nanowire is sprayed on the surface of the lithium metal to form a first functional layer 2 to obtain a first substrate, the first substrate is transported to a second spraying station, a solid-solution type metal fluoride and a non-solid-solution type metal fluoride are sprayed on the first substrate to form a second functional layer 3 to obtain a second substrate, the second substrate is transported to a third spraying station, an epoxy ether is sprayed on the second substrate to form an organic polymer layer 4 to obtain a fourth substrate 5, the fourth substrate 5 and a flexible solid electrolyte layer 6 are roll pressed to obtain a lithium negative electrode. Figure 1

[0137] In a fourth aspect, the present application provides a battery comprising the lithium negative electrode of the first aspect or prepared according to the preparation method of the second aspect.

[0138] Therefore, the battery has all the features and advantages of the lithium negative electrode described above, which will not be repeated here. In general, the battery has good capacity performance, excellent safety and cycle performance.

[0139] It can be understood that the battery can be a lithium battery, a solid oxide battery, etc., and the embodiments of the present application do not make specific limitations thereto.

[0140] In a fifth aspect, the present application provides an electrical equipment comprising the battery of the fourth aspect, and the battery supplies power to the electrical equipment.

[0141] Therefore, the electrical equipment has all the features and advantages of the battery described above, which will not be repeated here.

[0142] Specifically, the electrical equipment can be an electric vehicle, a hybrid vehicle or a smart terminal device (such as but not limited to a mobile phone), etc.

[0143] The present application will be described below through specific examples, and it should be noted that the specific examples below are only for illustrative purposes, and do not limit the scope of the present application in any way, and in addition, unless otherwise specified, the methods without specific description of conditions or steps are conventional methods, and the reagents and materials used can be obtained from commercial channels.

[0144] Example 1

[0145] Preparation of the lithium negative electrode:​

[0146] (1) Polyvinylpyrrolidone (PVP) with a mass ratio of 0.5:99.5 was uniformly mechanically stirred with 1,3-dioxolane, and then polyvinylpyrrolidone (PVP) with a mass of 4 times was uniformly mechanically stirred after ultrasonic dispersion of multi-walled carbon nanotubes to obtain a first mixed solution, which was sprayed at a spraying rate of 0.1 L / min -1 The first mixed solution was sprayed by air spraying to the lithium metal surface kept at 40°C to form a first functional layer, and a first substrate was obtained.

[0147] (2) A dimethyl carbonate solution of AgSbF6 and bis aluminum triflate with a concentration of 0.5 M was prepared to obtain a second mixed solution, which was sprayed at a spraying rate of 0.2 L / min -1 The second mixed solution was sprayed by air spraying onto the first substrate, and the solvent was removed by blowing dry air at 50°C to form a second functional layer, and a second substrate was obtained.

[0148] (3) The above steps were repeated to form the first functional layer and the second functional layer on both surfaces of the lithium metal.

[0149] (4) 1,3-dioxolane was uniformly sprayed to the second substrate and completely immersed the second functional layer at a spraying rate of 0.1 L / min-1 under the condition of air spraying, and was placed at 40°C for 20 minutes to form an organic polymer layer, and a third substrate was obtained.

[0150] (5) PVDF-HFP, LiTFSI, and LLZO powder with a particle size of 300 nm with a mass ratio of 4:4:2:40 were configured into a uniformly dispersed slurry, the slurry was coated on the surface of the release film by casting method, and the flexible solid-state electrolyte was obtained by vacuum drying at 70°C for 24h, the thickness of the flexible solid-state electrolyte was 20μm, the roll pressure was controlled to be 10% of the total thickness of the functional layer and the flexible solid-state electrolyte, and the flexible solid-state electrolyte layer was obtained by rolling. The prepared flexible solid-state electrolyte film was roll-composited with the third substrate and placed at room temperature for 12h to obtain an integrated lithium anode.

[0151] (6) Composite cathode preparation, NCM811, solid-state electrolyte, and carbon black with a mass ratio of 8:1:1 were prepared into a composite cathode slurry, which was coated on the surface of an aluminum foil current collector and dried at 80°C under vacuum to prepare a composite solid-state cathode. The prepared anode material and lithium anode were assembled into a coin cell for testing.

[0152] Example 2

[0153] The difference between this example and Example 1 is that this example does not include step (4) and step (5).

[0154] Example 3

[0155] The difference between this embodiment and embodiment 1 is that the inorganic nanowire in step 1 of this embodiment is titanium oxide.

[0156] Embodiment 4

[0157] The difference between this embodiment and embodiment 1 is that the inorganic nanowire in step 1 of this embodiment is tin sulfide.

[0158] Embodiment 5

[0159] The difference between this embodiment and embodiment 1 is that the inorganic nanowire in step 1 of this embodiment is titanium nitride.

[0160] Embodiment 6

[0161] The difference between this embodiment and embodiment 1 is that the inorganic nanowire in step 1 of this embodiment is one of solid electrolytes.

[0162] Embodiment 7

[0163] The difference between this embodiment and embodiment 1 is that the mass ratio of the multi-walled carbon nanotube to the polyvinylpyrrolidone in step 1 of this embodiment is 10:1.

[0164] Embodiment 8

[0165] The difference between this embodiment and embodiment 1 is that the spraying amount in step 1 of this embodiment is 1 L / min.

[0166] Embodiment 9

[0167] The difference between this embodiment and embodiment 1 is that the solid-solution type metal fluoride in step 2 of this embodiment is magnesium triflate, and the non-solid-solution type metal fluoride is zinc hexafluorophosphate.

[0168] Embodiment 10

[0169] The difference between this embodiment and embodiment 1 is that the concentration of the second mixed solution in step 2 of this embodiment is 0.1 mol / L. -1 .

[0170] Embodiment 11

[0171] The difference between this embodiment and embodiment 1 is that the concentration of the second mixed solution in step 2 of this embodiment is 3 mol / L. -1 .

[0172] Embodiment 12

[0173] The difference between this embodiment and embodiment 1 is that the spraying amount in step 2 of this embodiment is 0.4 L / min. -1 .

[0174] Embodiment 13

[0175] The difference between this embodiment and embodiment 1 is that the spraying volume in step 2 of this embodiment is 1Lmin -1 .

[0176] Comparative Example 1

[0177] This comparative example is different from Example 1 in that step 1 is not included in this comparative example.

[0178] Comparative Example 2

[0179] This comparative example is different from Example 1 in that step 2 is not included in this comparative example.

[0180] The following describes the battery performance test process and test results:

[0181] (1) Symmetrical battery test: In an inert gas glove box with water and oxygen content below 0.1 ppm, the polymer electrolyte membrane was assembled into a lithium metal / electrolyte / lithium metal button cell. -2 The current density is 0.1 mAh cm -2 Symmetrical battery cycling tests were performed at areal capacity.

[0182] (2) Battery cycle performance test

[0183] In an inert gas glove box with water and oxygen concentrations below 0.1 ppm, a polymer electrolyte membrane was assembled into a lithium nickel cobalt manganese oxide (NCM811) / electrolyte / lithium metal button cell. Charge and discharge cycling tests were conducted at a current density of 0.2C.

[0184] (3) AC impedance test

[0185] The assembled button-type Li metal / electrolyte / Li metal symmetrical battery was subjected to AC impedance testing under the test conditions of an amplitude of 10 mV and a test frequency of 1 MHz-0.1 Hz.

[0186] The results of testing the batteries of Examples 1-13 and Comparative Examples 1-2 according to the above process and method are shown in Table 1:

[0187] Table 1 Test results of Examples 1-13 and Comparative Examples 1-2

[0188]

[0189]

[0190] According to the results shown in Table 1:

[0191] According to the test results of Examples 1 to 13, the lithium batteries prepared with the lithium negative electrodes of the examples of the present application are superior to the lithium batteries prepared with the lithium negative electrodes of Comparative Examples 1 and 2 in terms of the first-cycle capacity retention rate and the number of cycles with 80% capacity retention rate. This shows that the lithium negative electrodes of the examples of the present application can effectively improve the coulombic efficiency and cycle life of the battery due to the synergistic effect of the first functional layer and the second functional layer.

[0192] Further, from Figure 2 The battery test results show that the battery of Example 1 has excellent coulombic efficiency and good cycle stability.

[0193] The above description is merely a preferred embodiment of the present application and an illustration of the technical principles employed. Those skilled in the art should understand that the scope of the invention herein is not limited to the technical solutions formed by the specific combination of the above-mentioned technical features, but also encompasses other technical solutions formed by any combination of the above-mentioned technical features or their equivalents without departing from the inventive concept. For example, a technical solution formed by replacing the above-mentioned features with (but not limited to) technical features having similar functions disclosed in this application.

Claims

1. A lithium negative electrode, characterized in that include: Lithium metal and a functional layer disposed on at least one surface of the lithium metal, the functional layer comprising a first functional layer and a second functional layer; Wherein, the first functional layer comprises inorganic nanowires, and the inorganic nanowires are distributed on the surface of the lithium metal to form an inorganic skeleton; The second functional layer includes lithiophilic metal particles, lithium alloy and lithium fluoride, and the lithiophilic metal particles, the lithium alloy and the lithium fluoride are distributed inside and / or on the surface of the inorganic framework.

2. The lithium negative electrode according to claim 1, characterized in that The inorganic nanowires include at least one of carbon nanotubes, oxides, sulfides, nitrides and inorganic solid electrolytes; the inorganic nanowires have a certain aspect ratio; The carbon nanotubes include single-walled carbon nanotubes or multi-walled carbon nanotubes; The oxide comprises at least one of lithium oxide, boron oxide, magnesium oxide, aluminum oxide, silicon oxide, titanium oxide, vanadium oxide, chromium oxide, manganese oxide, iron oxide, cobalt oxide, nickel oxide, copper oxide, zinc oxide, gallium oxide, tin oxide, molybdenum oxide, niobium oxide and bismuth oxide; The sulfide includes at least one of iron sulfide, cobalt sulfide, nickel sulfide, copper sulfide, zinc sulfide, tin sulfide, bismuth sulfide, tungsten sulfide and molybdenum sulfide; The nitride includes at least one of boron nitride, magnesium nitride, aluminum nitride, silicon nitride, titanium nitride, vanadium nitride, chromium nitride, manganese nitride, iron nitride, cobalt nitride, nickel nitride, copper nitride, zinc nitride, gallium nitride, tin nitride, molybdenum nitride, niobium nitride and bismuth nitride; The solid electrolyte includes at least one of LLZO, LLZTO, LLZAO, LLZNO, LLZGO, LLTO, LLTO, LTP, LATP and LAGP.

3. The lithium negative electrode according to claim 2, characterized in that The aspect ratio of the inorganic nanowire is 10-10000.

4. The lithium negative electrode according to claim 1, characterized in that The lithiophilic metal includes lithiated silver metal particles or magnesium metal particles.

5. The lithium negative electrode according to any one of claims 1 to 4, characterized in that The functional layer further includes an organic polymer layer, which is formed on the inorganic skeleton and forms a three-dimensional skeleton with the inorganic skeleton.

6. The lithium negative electrode according to claim 5, characterized in that The organic polymer layer includes at least one of PVDF, PEO, PU, ​​PMMA and PAN.

7. A method for preparing a lithium negative electrode, characterized in that: The lithium negative electrode includes lithium metal and a functional layer provided on at least one surface of the lithium metal, wherein the functional layer includes a first functional layer and a second functional layer, and specifically includes the following steps: The first functional layer is formed on the surface of the lithium metal to obtain a first matrix; the first functional layer includes inorganic nanowires, and the inorganic nanowires are distributed on the surface of the lithium metal to form an inorganic skeleton, The second functional layer is formed inside and / or on the surface of the inorganic skeleton to obtain the lithium negative electrode; the second functional layer includes the lithiophilic metal particles, the lithium alloy and the lithium fluoride.

8. The preparation method according to claim 7, characterized in that Forming the first functional layer on the surface of the lithium metal comprises: mixing the inorganic nanowires and a dispersant to obtain a first mixed solution; The first mixed liquid is sprayed onto the surface of the lithium metal and reacted to form the first functional layer to obtain the first substrate.

9. The preparation method according to claim 8, characterized in that In the process of mixing the inorganic nanowires and the dispersant to obtain the first mixed liquid, the dispersant includes a first dispersant and a second dispersant, and the first dispersant includes at least one of petroleum ether, 1,3-dioxolane, tetrahydrofuran, ethylene glycol dimethyl ether and dimethyl carbonate; The second dispersant includes polyvinyl pyrrolidone and / or polyethylene glycol.

10. The preparation method according to claim 9, characterized in that In the process of mixing the inorganic nanowires and the dispersant to obtain the first mixed solution, the mass ratio of the inorganic nanowires to the second dispersant is (2-10):

1.

11. The preparation method according to claim 8, characterized in that: In the process of spraying the first mixed liquid onto the surface of the lithium metal and reacting to form the first functional layer, the spraying method includes one of air spraying, high-pressure airless spraying and ultrasonic spraying; The spraying rate of the spraying method is 0.01Lmin -1 -1Lmin -1 , the reaction temperature is 10°C-95°C.

12. The preparation method according to claim 7, characterized in that: The second functional layer is formed inside and / or on the surface of the inorganic skeleton, comprising: dispersing a solid-solution type metal fluoride and a non-solid-solution type metal fluoride in a solvent to obtain a second mixed solution; The second mixed liquid is sprayed onto the first substrate to form the lithiophilic metal particles, the lithium alloy and the lithium fluoride inside and on the surface of the inorganic framework; wherein the solid-solution metal element includes a lithiophilic metal element.

13. The preparation method according to claim 12, characterized in that: In the process of dispersing a solid-solution type metal fluoride and a non-solid-solution type metal fluoride in a solvent to obtain a second mixed solution, the solid-solution type metal fluoride includes one of silver hexafluorophosphate, silver hexafluoroantimonate, silver pentafluoropropionate, silver tetrafluoroborate, silver trifluoromethanesulfonate, silver trifluoromethanethiol, silver bistrifluoromethanesulfonyl imide, silver methanesulfonate, magnesium trifluoromethanesulfonate and magnesium bistrifluoromethanesulfonyl imide; The non-solid-soluble metal fluoride includes one of hexafluorophosphate, potassium hexafluorotitanate, sodium hexafluorotitanate, potassium hexafluorozirconate, sodium hexafluorozirconate, potassium hexafluorotantalate, sodium hexafluorotantalate, potassium hexafluoroantimonate, sodium hexafluoroantimonate, a trifluoromethanesulfonate of a first metal, and a tetrafluoroborate of a second metal; wherein the first metal includes potassium, sodium, tin, aluminum, copper, zinc, scandium, bismuth, indium, hafnium, or ytterbium; and the second metal includes potassium, sodium, stannous, rubidium, calcium, iron, nickel, copper, zinc, or lead; The solvent comprises at least one of dimethyl carbonate, ethylene glycol dimethyl ether, triethylene glycol divinyl ether, petroleum ether, dimethyl sulfoxide, N,N-dimethylformamide, N,N-dimethylacetamide and N-methylpyrrolidone; The concentration of the second mixed solution is 0.1 mol / L -1 -3molL -1 .

14. The preparation method according to claim 12, characterized in that: Spraying the second mixed liquid onto the first substrate, wherein the spraying method includes one of air spraying, high-pressure airless spraying and ultrasonic spraying; The spraying rate of the spraying method is 0.01Lmin -1 -1Lmin -1 Preferably, the spraying amount of the spraying method is 0.2Lmin -1 -0.4Lmin -1 .

15. The preparation method according to claim 7, characterized in that: After forming the second functional layer inside and on the surface of the inorganic skeleton, the preparation method further comprises: The epoxy ether is sprayed on the second functional layer and immersed in the inorganic skeleton, the lithiophilic metal particles, the lithium alloy and the lithium fluoride to react and form the organic polymer layer.

16. The preparation method according to claim 15, characterized in that: The spraying volume of the spraying method is 0.01Lmin -1 -1L min -1 , the reaction temperature is 0-100°C.

17. A battery, characterized in that: The invention comprises the lithium negative electrode according to any one of claims 1 to 6 or the lithium negative electrode prepared according to the preparation method according to any one of claims 7 to 16.

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