Silicon-containing negative electrode structure

Abstract

The invention belongs to the technical field of batteries, and particularly relates to a silicon-containing negative electrode structure which comprises a silicon-containing negative electrode, a first artificial SEI layer deposited on the surface of the silicon-containing negative electrode by adopting ALD, a second artificial SEI layer deposited on the surface of the first artificial SEI layer by adopting MLD, and a third artificial SEI layer deposited on the second artificial SEI layer by adopting ALD. Compared with the prior art, through ingenious structural design and material selection, the three artificial SEI layers are constructed on the surface of the silicon-containing negative electrode, the binding force between the modification layer and the substrate pole piece and a continuous ion conduction path can be ensured, SEI structure collapse caused by volume expansion in the charging and discharging process is prevented, and the service life of the silicon-containing negative electrode is prolonged. The structural integrity of the modification layer is improved, so that the cycle stability and cycle life of the silicon-containing negative electrode are improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of batteries, and particularly relates to a silicon-containing negative electrode structure. Background Art

[0002] The surface of the electrode material plays an important role in the electrochemical reaction process of the battery. The stability and reactivity of the surface and interface dominate the progress of the electrochemical reaction. Chemical and physical modification of the electrode material surface can effectively improve the interfacial reaction, conductivity, and structural integrity. Traditional spin coating or solution methods have problems such as a relatively thick thickness and poor coating uniformity, seriously affecting the performance and stability of the battery capacity. To overcome the above problems, atomic layer deposition technology can precisely control the thickness, composition, and morphology of the surface modification layer through its chemical adsorption and self-limiting properties.

[0003] With the increasing demand for high-energy-density lithium batteries, Si and its Si composite negative electrodes have attracted much attention due to their ultra-high theoretical capacity density. However, the Si negative electrode has a large volume change during charge and discharge. The oxide coatings prepared by traditional methods cannot meet such a large volume expansion, resulting in the destruction of the SEI layer and the continuous consumption of active Li in the electrolyte, ultimately causing a decrease in the Coulomb efficiency and shortening the cycle life of the battery.

[0004] To improve the mechanical strength and toughness of the surface modification layer of Si and its Si composite electrodes to cope with the volume change during cycling, although the nanoscale ALD oxide modification layer has certain flexibility, it is not sufficient to ensure the structural stability during long cycling.

[0005] In view of this, the present invention aims to provide a silicon-containing negative electrode structure. Through ingenious structural design and material selection, by constructing a three-layer artificial SEI layer on the surface of the silicon-containing negative electrode, it can ensure the bonding force between the modification layer and the substrate electrode and a continuous ion conduction path, prevent the collapse of the SEI structure caused by volume expansion during charge and discharge, improve the structural integrity of the modification layer, and thus improve the cycle stability and cycle life of the silicon-containing negative electrode. Summary of the Invention

[0006] The purpose of the present invention is to provide a silicon-containing negative electrode structure in view of the deficiencies of the prior art. Through ingenious structural design and material selection, by constructing a three-layer artificial SEI layer on the surface of the silicon-containing negative electrode, it can ensure the bonding force between the modification layer and the substrate electrode and a continuous ion conduction path, prevent the collapse of the SEI structure caused by volume expansion during charge and discharge, improve the structural integrity of the modification layer, and thus improve the cycle stability and cycle life of the silicon-containing negative electrode.

[0007] To achieve the above purpose, the present invention adopts the following technical solutions:

[0008] A silicon-containing anode structure includes a silicon-containing anode, a first artificial SEI layer deposited on the surface of the silicon-containing anode by ALD, a second artificial SEI layer deposited on the surface of the first artificial SEI layer by MLD, and a third artificial SEI layer deposited on the surface of the second artificial SEI layer by ALD. The setting of the three artificial SEI layers has the following advantages: the first artificial SEI layer can improve the bonding force between the coating layer and the substrate, and at the same time construct a continuous ion-conducting network; the second artificial SEI layer relies on its excellent fracture toughness to ensure the structural stability and integrity of the overall coating layer during the cyclic process of the Si anode with severe volume expansion, and at the same time constructs a continuous electron-conducting network through its own carbon-containing segments; due to the poor water vapor stability of the organic-inorganic composite, the third artificial SEI layer can effectively block the erosion of water vapor in the air and HF in the electrolyte, playing the role of an anti-corrosion layer and further stabilizing the stability of the overall SEI layer. The functions of each layer are different and the order cannot be changed; the advantage of the selection of each layer process is that it can accurately control the thickness and composition of the film layer to achieve precise regulation of electrochemical and mechanical properties.

[0009] As an improvement of the silicon-containing anode structure of the present invention, the thickness of the first artificial SEI layer is 1-5 nm, the thickness of the second artificial SEI layer is 1-20 nm, and the thickness of the third artificial SEI layer is 1-5 nm. The selection of the above thicknesses has the following advantages: the thicknesses of the first layer and the third layer cannot be too thick, because too thick a thickness is likely to increase the internal resistance of the battery, hinder the transmission speed of electrons and ions, and reduce the reaction kinetics performance of the battery. The second artificial SEI layer cannot be too thick, because too thick a thickness is likely to cause the consumption of active lithium in the electrode, resulting in capacity loss, and too thin a thickness is likely to cause damage to the SEI layer due to insufficient mechanical properties.

[0010] As an improvement of the silicon-containing anode structure of the present invention, the material of the first artificial SEI layer is an oxide or a solid electrolyte ion-conducting material.

[0011] As an improvement of the silicon-containing anode structure of the present invention, the chemical general formula of the oxide is MO x , where M is at least one of Al, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Y, Zr, Nb, Mo, Ru, La, Ce, Hf, Ta, W, Mg, In, Sn, and Si, and 1≤x≤5.

[0012] The chemical general formula of the solid electrolyte ion conductor is Li x A3B2O 12 wherein, A is at least one of Y, Pr, Nd, La, B is at least one of Te, Nb, Ta, Sb, Zr, Sn, Hf, and 1≤x≤7;

[0013] The solid electrolyte ion conductor is specifically Li3Y3Te2O 12 , Li3Pr3Te2O 12 , Li3Nd3Te2O 12 , Li5La3Ta2O 12 , Li5La3Nb2O 12 , Li5La3Sb2O 12 , Li5Nd3Sb2O 12 , Li6MgLa2Ta2O 12 , Li6CaLa2Ta2O 12 , Li6BaLa2Ta2O 12 , Li6BaLa2Nb2O 12 , Li7La3Sn2O 12 , Li7La3Zr2O 12 , Li7La3Hf2O 12 , LiTiO2, LiAlO2, LiZrO, LiCeO2, LiMnO2, LiBO2, LiTaO3, Li2TiO3, Li2SiO3, Li2ZrO3, Li2CO3, Li4Ti5O 12 , at least one of Li5AlO4.

[0014] As an improvement to the silicon-containing anode structure of the present invention, the material of the second artificial SEI layer is a porous organic-inorganic compound layer, and its porosity is 10-30%.

[0015] As an improvement to the silicon-containing anode structure of the present invention, the general formula of the organic-inorganic porous layer is X-cone, where X is at least one of Al, Zn, Ti, Zr, Hf, V, Sn. The specific material of the organic-inorganic porous layer is various metal X-based + organic ligands. The types of organic ligands are at least one of EG (ethylene glycol), GL (glycerol), TPA (terephthalic acid), Li2TP (lithium terephthalate), THD, (2,2,6,6-tetramethyl-3,5-heptanedioate), TPA-NH2-2 (aminonorephthalic acid), PDC (pyridinedicarboxylic acid), NDC-2,6- (naphthalenedicarboxylic acid), BPDC (4,4'-biphenyldicarboxylic acid), ZAO (4,4'-azobenzenedicarboxylic acid), HQ (hydroquinone), PD (propylene glycol).

[0016] As an improvement to the silicon-containing anode structure of the present invention, the third artificial SEI layer is an anti-corrosion layer.

[0017] As an improvement of the silicon-containing anode structure of the present invention, the anti-corrosion layer is at least one of ZrO2, HfO2, Al2O3 and fluoride AFx, where A is one of Li, Al, Sc, Zr, La, Sm, Ce and Bi, and 1≤x≤4.

[0018] The advantages of the selection of the above three layers of materials are as follows: constructing a continuous ionic and electronic conductive network, ensuring the bonding force between the SEI layer and the substrate, while resisting the severe volume expansion of the Si anode and maintaining the structural integrity of the SEI layer. At the same time, the outermost anti-corrosion layer can effectively resist the erosion of water vapor and HF, ensuring the stability of the SEI layer. As an improvement of the silicon-containing anode structure of the present invention, the preparation method of the first artificial SEI layer is time-type or space-type ALD;

[0019] As an improvement of the silicon-containing anode structure of the present invention, the preparation method of the second artificial SEI layer is time-type or space-type MLD;

[0020] As an improvement of the silicon-containing anode structure of the present invention, the preparation method of the third artificial SEI layer is time-type or space-type ALD.

[0021] As an improvement of the silicon-containing anode structure of the present invention, the time-type ALD method for preparing the first artificial SEI layer includes the following steps:

[0022] First step, dispose the Si anode active material layer on the negative electrode current collector to obtain a pole piece;

[0023] Second step, place the pole piece obtained in the first step in an atomic layer deposition chamber, and introduce a metal organic compound precursor, and the precursor is chemically adsorbed on the surface layer of the negative electrode active material;

[0024] Third step, introduce an oxygen-containing reactant into the atomic layer deposition chamber to react the oxygen-containing reactant with the adsorbed precursor;

[0025] Fourth step, repeat the second step and the third step, and deposit cyclically to form a first artificial SEI ion-conducting layer;

[0026] The oxygen-containing reactant is H2O, O3 or O2 plasma.

[0027] The space-type ALD method for preparing the first artificial SEI layer includes the following steps:

[0028] First step, dispose the Si anode active material layer on the negative electrode current collector to obtain a pole piece;

[0029] Second step, place the pole piece obtained in the first step in a space-type atomic layer deposition system. After evacuating, introduce an isolation gas, a precursor, and an oxygen-containing reactant into the space-type atomic layer deposition system in sequence or simultaneously;

[0030] In the third step, start the moving mechanism to move the pole piece through the deposition area of the system at least once, that is, form the first layer of artificial SEI protective layer.

[0031] The oxygen-containing reactant is H2O, O3 or oxygen plasma; the isolation gas is N2, He or Ar.

[0032] The feeding speed of the isolation gas is 0.1 - 500 SLM, the moving speed of the moving mechanism is 0.01 - 300 m / min, and the precursor is a metal organic compound and / or a silicon-containing organic compound, where the silicon-containing organic compound is specifically at least one of bis(diethylamino)silane, tetra(ethylmethylamino)silane, trimethoxysilanol, diisopropylaminosilane, and bis(tert-butylamino)silane.

[0033] As an improvement of the silicon-containing negative electrode structure of the present invention, the time-based MLD method for preparing the second artificial SEI layer includes the following steps:

[0034] In the first step, place the Si negative electrode pole piece deposited with the first layer of artificial SEI layer in the molecular layer deposition cavity, and introduce the metal organic compound precursor, and the precursor is chemically adsorbed on the surface of the negative electrode active material coated with the first layer of artificial SEI layer.

[0035] In the second step, introduce an organic ligand into the molecular layer deposition cavity to react the organic ligand with the adsorbed precursor.

[0036] In the third step, repeat the first step and the second step, and deposit cyclically to form the second layer of artificial SEI layer.

[0037] The organic ligand is at least one of EG (ethylene glycol), GL (glycerol), TPA (terephthalic acid), Li2TP (lithium terephthalate), THD, (2,2,6,6-tetramethyl-3,5-heptanedioate), TPA-NH2-2 (aminonorephthalic acid), PDC (pyridine dicarboxylic acid), NDC-2,6-(naphthalene dicarboxylic acid), BPDC (4,4'-biphenyl dicarboxylic acid), ZAO (4,4'-azobenzene dicarboxylic acid), HQ (hydroquinone), and PD (propylene glycol).

[0038] The spatial MLD method for preparing the second artificial SEI layer includes the following steps:

[0039] In the first step, after evacuating the Si negative electrode pole piece deposited with the first layer of artificial SEI layer in the molecular layer deposition cavity, introduce the isolation gas, the precursor, and the organic ligand into the spatial molecular layer deposition system in sequence or simultaneously.

[0040] In the second step, start the moving mechanism to move the pole piece through the deposition area of the system at least once, that is, form the second artificial SEI protective layer; the isolation gas is N2, He or Ar;

[0041] The feeding speed of the isolation gas is 0.1-500 SLM, the moving speed of the moving mechanism is 0.01-300 m / min, the precursor is a metal organic compound and / or a silicon-containing organic compound, and the silicon-containing organic compound is specifically at least one of bis(diethylamino)silane, tetra(ethylmethylamino)silane, trimethoxysilanol, diisopropylaminosilane and bis(tert-butylamino)silane; the organic ligand is EG (ethylene glycol), GL (glycerol), TPA (terephthalic acid), Li2TP (lithium terephthalate), THD, (2,2,6,6-tetramethyl-3,5-heptanedioate), TPA-NH2-2 (aminonorephthalic acid), PDC (pyridinedicarboxylic acid), NDC-2,6-(naphthalenedicarboxylic acid), BPDC (4,4′-biphenyldicarboxylic acid), ZAO (4,4′-azobenzenedicarboxylic acid), HQ (hydroquinone), PD (propylene glycol).

[0042] As an improvement of the silicon-containing negative electrode structure of the present invention, the time-type ALD method for preparing the third artificial SEI layer includes the following steps:

[0043] In the first step, place the pole piece deposited with the first and second artificial SEI layers in the atomic layer deposition chamber, and introduce the metal organic compound precursor, and the precursor is chemically adsorbed on the surface of the pole piece coated with the second artificial SEI layer;

[0044] In the second step, introduce an oxygen-containing reactant or a fluorine-containing compound into the atomic layer deposition chamber to react the oxygen-containing reactant or the fluorine-containing compound with the adsorbed precursor;

[0045] In the third step, repeat the first step and the second step, and deposit cyclically to form the third artificial SEI anti-corrosion layer;

[0046] The oxygen-containing reactant is H2O, O3 or O2 plasma; the fluorine-containing compound is at least one of HF (hydrogen fluoride), NH4F (ammonium fluoride) and F2 (fluorine gas).

[0047] The spatial ALD method for preparing the third artificial SEI layer includes the following steps:

[0048] In the first step, place the pole piece deposited with the first and second artificial SEI layers in the spatial atomic layer deposition system. After evacuating, introduce the isolation gas, precursor, oxygen-containing reactant or fluorine-containing compound into the spatial atomic layer deposition system in sequence or simultaneously;

[0049] In the second step, start the moving mechanism to move the pole piece through the deposition area of the system at least once, that is, form the third layer of artificial SEI protective layer.

[0050] The oxygen-containing reactant is H2O, O3 or oxygen plasma; the isolation gas is an inert gas such as N2, He or Ar; the fluorine-containing compound is at least one of HF (hydrogen fluoride), NH4F (ammonium fluoride) and F2 (fluorine gas).

[0051] The feeding speed of the isolation gas is 0.1 - 500 SLM, the moving speed of the moving mechanism is 0.01 - 300 m / min, and the precursor is a metal organic compound and / or a silicon-containing organic compound. The silicon-containing organic compound is specifically at least one of bis(diethylamino)silane, tetra(ethylmethylamino)silane, trimethoxysilanol, diisopropylaminosilane and bis(tert-butylamino)silane.

[0052] The types of metal organic compound precursors in the present invention are shown in the following table:

[0053] Table 1: Types of precursors corresponding to various metals

[0054]

[0055]

[0056] In the present invention, the silicon-containing organic compound is a precursor for depositing a silicon-containing solid electrolyte (such as Li2SiO3) or an oxide.

[0057] In the present invention, the composition of the silicon-containing negative electrode is that the active material is at least one of pure silicon, nano-silicon, or a composite material of silicon such as a silicon-carbon composite material (silicon-graphite, silicon-carbon nanotube, silicon-graphene), and silicon oxide; the conductive agent is at least one of SuperP, carbon nanotube, graphene and carbon black; the binder is at least one of PVDF, CMC and SBR.

[0058] Compared with the prior art, through ingenious structural design and material selection, the present invention constructs three layers of artificial SEI layers on the surface of the silicon-containing negative electrode, which can ensure the bonding force between the modified layer and the substrate pole piece and a continuous ion-electron conduction path, prevent the collapse of the SEI structure caused by volume expansion during charge and discharge, improve the structural integrity of the modified layer, and at the same time resist the erosion of water vapor and HF, ensure the stability of the SEI layer, thereby improving the cycle stability and cycle life of the silicon-containing negative electrode.

[0059] Specifically, the first-layer ALD oxide or solid electrolyte layer, as an ion-conducting layer, can construct a continuous ion transport framework from the electrode to the artificial SEI layer, and by constructing covalent bonds, enhance the binding force between the modified layer and the electrode. Due to the higher crosslinking degree between the metal precursor and the polymer segments, the middle porous organic-inorganic composite layer has better fracture toughness than a single inorganic layer, and can effectively adapt to the volume expansion of the electrode during charge and discharge while maintaining the integrity of the modified layer. At the same time, a continuous electron-conducting network is constructed through its own carbon-containing segments, enhancing the electron conduction ability of the SEI layer and improving the reaction kinetics of the battery. The outermost ALD oxide anti-corrosion layer can effectively block the erosion of water vapor and, as a sacrificial layer, further adsorb the corrosion of HF that may exist in the electrolyte, thus playing a role in protecting the electrode and the artificial SEI film. Therefore, the design of the three-layer structure can ensure the binding force between the modified layer and the substrate electrode, a continuous ion-electron conduction path, prevent the collapse of the SEI structure caused by volume expansion during charge and discharge, improve the structural integrity of the modified layer, and thus enhance the cycle stability and cycle life of the Si negative electrode. Description of the Drawings

[0060] Figure 1 is a schematic structural diagram of the present invention. Detailed Embodiments

[0061] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0062] It should be noted that all directional indications (such as up, down, left, right, front, back...) in the embodiments of the present invention are only used to explain the relative positional relationship and movement conditions between components in a specific posture (as shown in the drawings). If this specific posture changes, the directional indications will also change accordingly.

[0063] In addition, the descriptions involving "first", "second", etc. in the present invention are only for descriptive purposes, and cannot be understood as indicating or implying their relative importance or implicitly indicating the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include at least one of such features. In addition, the technical solutions between various embodiments can be combined with each other, but it must be based on the fact that those of ordinary skill in the art can implement them. When the combination of technical solutions conflicts or cannot be implemented, it should be considered that such a combination of technical solutions does not exist and is not within the protection scope required by the present invention.

[0064] Example 1

[0065] As Figure 1 shown, this embodiment provides a silicon-containing negative electrode structure, including a silicon-containing negative electrode 1, a first artificial SEI layer 2 deposited on the surface of the silicon-containing negative electrode 1 by ALD, a second artificial SEI layer 3 deposited on the surface of the first artificial SEI layer 2 by MLD, and a third artificial SEI layer 4 deposited on the second artificial SEI layer 3 by ALD.

[0066] Among them, the thickness of the first artificial SEI layer is 2 nm, the thickness of the second artificial SEI layer is 4 nm, and the thickness of the third artificial SEI layer is 2 nm.

[0067] The material of the first artificial SEI layer is copper oxide, the material of the second artificial SEI layer is a porous organic-inorganic compound layer with a porosity of 20%, the general formula of the organic-inorganic porous layer is X-cone, where X is Zn, and the specific material of the organic-inorganic porous layer is Zn plus an organic ligand, where the organic ligand is EG (ethylene glycol). The third artificial SEI layer is an anti-corrosion layer ZrO2.

[0068] The time-based ALD method for preparing the first artificial SEI layer includes the following steps:

[0069] The first step is to place the Si negative electrode active material layer on the negative electrode current collector to obtain a pole piece;

[0070] The second step is to place the pole piece obtained in the first step in an atomic layer deposition chamber, and introduce the metal organic compound precursor bis(dimethylamine-2-propanol)copper, and the precursor is chemically adsorbed on the surface layer of the negative electrode active material;

[0071] The third step is to introduce the oxygen-containing reactant ozone into the atomic layer deposition chamber to react the oxygen-containing reactant with the adsorbed precursor;

[0072] The fourth step is to repeat the second step and the third step, and deposit cyclically to form the first artificial SEI ion-conducting layer.

[0073] The time-based MLD method for preparing the second artificial SEI layer includes the following steps:

[0074] The first step is to place the Si negative electrode pole piece deposited with the first layer of artificial SEI layer in a molecular layer deposition chamber, and introduce the metal organic compound precursor diethyl zinc, and the precursor is chemically adsorbed on the surface layer of the negative electrode active material coated with the first layer of artificial SEI layer;

[0075] The second step is to introduce the organic ligand ethylene glycol into the molecular layer deposition chamber to react the organic ligand with the adsorbed precursor;

[0076] The third step is to repeat the first step and the second step, and deposit cyclically to form the second layer of artificial SEI layer.

[0077] The time-based ALD method for preparing the third artificial SEI layer includes the following steps:

[0078] In the first step, the electrode sheet deposited with the first and second artificial SEI layers is placed in an atomic layer deposition chamber, and the metal organic compound precursor zirconium tetrakis(dimethylamino) is introduced. The precursor is chemically adsorbed on the surface of the electrode sheet coated with the second artificial SEI layer;

[0079] In the second step, an oxygen-containing reactant H2O is introduced into the atomic layer deposition chamber to react the oxygen-containing reactant with the adsorbed precursor;

[0080] In the third step, the first and second steps are repeated for cyclic deposition to form a third artificial SEI anti-corrosion layer.

[0081] Example 2

[0082] As Figure 1 shown, this example provides a silicon-containing negative electrode structure, including a silicon-containing negative electrode 1, a first artificial SEI layer 2 deposited on the surface of the silicon-containing negative electrode 1 by ALD, a second artificial SEI layer 3 deposited on the surface of the first artificial SEI layer 2 by MLD, and a third artificial SEI layer 4 deposited on the second artificial SEI layer 3 by ALD.

[0083] The thickness of the first artificial SEI layer 2 is 1.5 nm, the thickness of the second artificial SEI layer 3 is 7 nm, and the thickness of the third artificial SEI layer 4 is 3 nm.

[0084] The material of the first artificial SEI layer 2 is a solid electrolyte ion-conducting material Li3Y3Te2O 12 .

[0085] The material of the second artificial SEI layer 3 is a porous organic-inorganic compound layer with a porosity of 18%. The general formula of the organic-inorganic porous layer is X-cone, where X is Ti, and the specific material of the organic-inorganic porous layer is various Ti-based plus organic ligand GL (glycerol).

[0086] The third artificial SEI layer is an anti-corrosion layer HfO2.

[0087] The spatial ALD method for preparing the first artificial SEI layer includes the following steps:

[0088] In the first step, the Si negative electrode active material layer is disposed on the negative electrode current collector to obtain an electrode sheet;

[0089] In the second step, place the electrode sheet obtained in the first step into a spatial atomic layer deposition system. After evacuating the air, introduce the isolation gas nitrogen, precursors (tert-butyl lithium, tris(methylcyclopentadienyl)yttrium, tellurium chloride), and the oxygen-containing reactant O3 into the spatial atomic layer deposition system successively or simultaneously; the introduction rate of the isolation gas is 100 SLM, and the moving speed of the moving mechanism is 100 m / min.

[0090] In the third step, start the moving mechanism to move the electrode sheet through the deposition area of the system at least once, thereby forming the first artificial SEI protective layer.

[0091] The spatial MLD method for preparing the second artificial SEI layer includes the following steps:

[0092] In the first step, place the Si negative electrode sheet deposited with the first artificial SEI layer into the molecular layer deposition cavity. After evacuating the air, introduce the isolation gas nitrogen, the precursors tris(methylcyclopentadienyl)yttrium, tert-butyl lithium, and tellurium chloride, and the organic ligand glycerol into the spatial molecular layer deposition system successively or simultaneously;

[0093] In the second step, start the moving mechanism to move the electrode sheet through the deposition area of the system at least once, thereby forming the second artificial SEI protective layer; the introduction rate of the isolation gas is 200 SLM, and the moving speed of the moving mechanism is 100 m / min.

[0094] The spatial ALD method for preparing the third artificial SEI layer includes the following steps:

[0095] In the first step, place the electrode sheet deposited with the first and second artificial SEI layers into the spatial atomic layer deposition system. After evacuating the air, introduce the isolation gas nitrogen, the precursors dichlorobis(isopropylcyclopentadienyl)hafnium, and oxygen plasma into the spatial atomic layer deposition system successively or simultaneously;

[0096] In the second step, start the moving mechanism to move the electrode sheet through the deposition area of the system at least once, thereby forming the third artificial SEI protective layer; the introduction rate of the isolation gas is 150 SLM, and the moving speed of the moving mechanism is 120 m / min.

[0097] Example 3

[0098] As Figure 1 shown, this example provides a silicon-containing negative electrode structure, including a silicon-containing negative electrode 1, a first artificial SEI layer 2 deposited on the surface of the silicon-containing negative electrode 1 by ALD, a second artificial SEI layer 3 deposited on the surface of the first artificial SEI layer 2 by MLD, and a third artificial SEI layer 4 deposited on the second artificial SEI layer 3 by ALD.

[0099] The thickness of the first artificial SEI layer 2 is 1.5 nm, the thickness of the second artificial SEI layer 3 is 16 nm, and the thickness of the third artificial SEI layer 4 is 1.5 nm.

[0100] The material of the first artificial SEI layer is Al2O3. The material of the second artificial SEI layer is a porous organic-inorganic compound layer with a porosity of 22%. The general formula of the organic-inorganic porous layer is X-cone, where X is Al. The specific material of the organic-inorganic porous layer is various Al-based materials plus TPA (terephthalic acid). The third artificial SEI layer is an anti-corrosion layer of LiF.

[0101] The time-type ALD method for preparing the first artificial SEI layer includes the following steps:

[0102] First step, set the Si negative electrode active material layer on the negative electrode current collector to obtain a pole piece;

[0103] Second step, place the pole piece obtained in the first step in an atomic layer deposition chamber, and introduce the metal organic compound precursor trimethylaluminum. The precursor is chemically adsorbed on the surface of the negative electrode active material;

[0104] Third step, introduce O2 plasma into the atomic layer deposition chamber to react the O2 plasma with the adsorbed precursor;

[0105] Fourth step, repeat the second step and the third step, and deposit cyclically to form the first artificial SEI ion-conducting layer;

[0106] The space MLD method for preparing the second artificial SEI layer includes the following steps:

[0107] First step, after evacuating the Si negative electrode pole piece deposited with the first layer of artificial SEI layer in a molecular layer deposition chamber, introduce the isolation gas argon, the precursor trimethylaluminum, and the organic ligand TPA (terephthalic acid) into the space-type molecular layer deposition system in sequence or simultaneously;

[0108] Second step, start the moving mechanism to move the pole piece through the deposition area of the system at least once, that is, form the second artificial SEI protection layer; the introduction speed of the isolation gas is 50 SLM, and the moving speed of the moving mechanism is 40 m / min.

[0109] The time-type ALD method for preparing the third artificial SEI layer includes the following steps:

[0110] First step, place the pole piece deposited with the first and second artificial SEI layers in an atomic layer deposition chamber, and introduce the metal organic compound precursors ((2,2,6,6-tetramethyl-3,5-heptanedione) lithium and the precursors are chemically adsorbed on the surface of the pole piece coated with the second artificial SEI layer;

[0111] In the second step, introduce HF (hydrogen fluoride), NH4F (ammonium fluoride), and F2 (fluorine gas) into the atomic layer deposition chamber, and react the fluorine-containing reactants with the adsorbed precursors;

[0112] In the third step, repeat the first step and the second step, and perform cyclic deposition to form a third artificial SEI anti-corrosion layer.

[0113] Example 4

[0114] As Figure 1 shown, this example provides a silicon-containing anode structure, including a silicon-containing anode 1, a first artificial SEI layer 2 deposited on the surface of the silicon-containing anode 1 by ALD, a second artificial SEI layer 3 deposited on the surface of the first artificial SEI layer 2 by MLD, and a third artificial SEI layer 4 deposited on the second artificial SEI layer 3 by ALD.

[0115] The thickness of the first artificial SEI layer 2 is 2 nm, the thickness of the second artificial SEI layer 3 is 15 nm, and the thickness of the third artificial SEI layer 4 is 2 nm.

[0116] The material of the first artificial SEI layer 2 is Li6BaLa2Nb2O 12 . The material of the second artificial SEI layer is a porous organic-inorganic compound layer, its porosity is 12%, the general formula of the organic-inorganic porous layer is X-cone, where X is Zr, and the specific material of the organic-inorganic porous layer is various metal Zr-based plus organic ligand Li2TP. The third artificial SEI layer 4 is an anti-corrosion layer Al2O3.

[0117] The spatial ALD method for preparing the first artificial SEI layer includes the following steps:

[0118] In the first step, set the Si anode active material layer on the anode current collector to obtain a pole piece;

[0119] In the second step, place the pole piece obtained in the first step in a spatial atomic layer deposition system. After evacuating, introduce the isolation gas N2, precursors (tert-butyl lithium, tert-butylimino tris(ethylmethylamino)niobium, bis(triisopropylcyclopentadienyl)barium, and tris(cyclopentadienyl)lanthanum), and O3 into the spatial atomic layer deposition system in sequence or simultaneously;

[0120] In the third step, start the moving mechanism to move the pole piece through the deposition area of the system at least once, that is, form the first layer of artificial SEI protection layer;

[0121] The introduction speed of the isolation gas is 320 SLM, and the moving speed of the moving mechanism is 10 m / min.

[0122] The time-based MLD method for preparing the second artificial SEI layer includes the following steps:

[0123] First step: Place the Si negative electrode sheet deposited with the first artificial SEI layer into the molecular layer deposition chamber, and introduce the metal organic compound precursor bis(cyclopentadienyl)dimethylzirconium. The precursor is chemically adsorbed on the surface of the negative electrode active material coated with the first artificial SEI layer.

[0124] Second step: Introduce the organic ligand Li2TP into the molecular layer deposition chamber to react the organic ligand with the adsorbed precursor.

[0125] Third step: Repeat the first step and the second step, and deposit cyclically to form the second artificial SEI layer.

[0126] The time-based ALD method for preparing the third artificial SEI layer includes the following steps:

[0127] First step: Place the electrode sheet deposited with the first and second artificial SEI layers into the atomic layer deposition chamber, and introduce the metal organic compound precursor trimethylaluminum. The precursor is chemically adsorbed on the surface of the electrode sheet coated with the second artificial SEI layer.

[0128] Second step: Introduce the oxygen-containing reactant O3 into the atomic layer deposition chamber to react the oxygen-containing reactant with the adsorbed precursor.

[0129] Third step: Repeat the first step and the second step, and deposit cyclically to form the third artificial SEI anti-corrosion layer.

[0130] Example 5

[0131] As Figure 1 shown, this example provides a silicon-containing negative electrode structure, including a silicon-containing negative electrode 1, a first artificial SEI layer 2 deposited on the surface of the silicon-containing negative electrode 1 by ALD, a second artificial SEI layer 3 deposited on the surface of the first artificial SEI layer 2 by MLD, and a third artificial SEI layer 4 deposited on the second artificial SEI layer 3 by ALD.

[0132] The thickness of the first artificial SEI layer 2 is 1.5 nm, the thickness of the second artificial SEI layer 3 is 12 nm, and the thickness of the third artificial SEI layer 4 is 3 nm.

[0133] The material of the first artificial SEI layer 2 is Li7La3Zr2O 12 .

[0134] The material of the second artificial SEI layer 3 is a porous organic-inorganic compound layer, its porosity is 16%, the general formula of the organic-inorganic porous layer is X-cone, where X is Li, and the specific material of the organic-inorganic porous layer is various Li-based plus the organic ligand propylene glycol.

[0135] The third artificial SEI layer is at least one of the anti-corrosion layer AlF3.

[0136] The time-type ALD method for preparing the first artificial SEI layer includes the following steps:

[0137] First step, a Si negative electrode active material layer is disposed on a negative electrode current collector to obtain an electrode sheet;

[0138] Second step, the electrode sheet obtained in the first step is placed in an atomic layer deposition chamber, and a metal organic compound precursor (precursors: zirconium tetrakis(dimethylamino), lithium (2,2,6,6-tetramethyl-3,5-heptanedionate), lanthanum tris(cyclopentadienyl)) is introduced. The precursor is chemically adsorbed on the surface layer of the negative electrode active material;

[0139] Third step, O2 plasma is introduced into the atomic layer deposition chamber to react the O2 plasma with the adsorbed precursor;

[0140] Fourth step, the second and third steps are repeated for cyclic deposition to form the first artificial SEI ion-conducting layer;

[0141] The space MLD method for preparing the second artificial SEI layer includes the following steps:

[0142] First step, after evacuating the Si negative electrode sheet deposited with the first artificial SEI layer in a molecular layer deposition chamber, an inert gas argon, a precursor tert-butyl lithium, and an organic ligand propylene glycol are introduced into the spatial molecular layer deposition system in sequence or simultaneously;

[0143] Second step, a moving mechanism is started to move the electrode sheet through the deposition area of the system at least once, namely, the second artificial SEI protective layer is formed; the introduction speed of the inert gas is 60 SLM, and the moving speed of the moving mechanism is 10 m / min.

[0144] The space ALD method for preparing the third artificial SEI layer includes the following steps:

[0145] First step, the electrode sheet deposited with the first and second artificial SEI layers is placed in a spatial atomic layer deposition system. After evacuation, an inert gas argon, a precursor (triethylaluminum), HF (hydrogen fluoride), NH4F (ammonium fluoride), and F2 (fluorine gas) are introduced into the spatial atomic layer deposition system in sequence or simultaneously;

[0146] Second step, a moving mechanism is started to move the electrode sheet through the deposition area of the system at least once, namely, the third artificial SEI protective layer is formed;

[0147] The introduction speed of the inert gas is 230 SLM, and the moving speed of the moving mechanism is 140 m / min.

[0148] Example 6

[0149] AsFigure 1 As shown in the figure, this embodiment provides a silicon-containing negative electrode structure, including a silicon-containing negative electrode 1, a first artificial SEI layer 2 deposited on the surface of the silicon-containing negative electrode 1 by ALD, a second artificial SEI layer 3 deposited on the surface of the first artificial SEI layer 2 by MLD, and a third artificial SEI layer 4 deposited on the second artificial SEI layer 3 by ALD.

[0150] Among them, the thickness of the first artificial SEI layer is 1 nm, the thickness of the second artificial SEI layer is 9 nm, and the thickness of the third artificial SEI layer is 3 nm.

[0151] The material of the first artificial SEI layer is tin oxide. The material of the second artificial SEI layer is a porous organic-inorganic compound layer with a porosity of 19%. The general formula of the organic-inorganic porous layer is X-cone, where X is V. The specific material of the organic-inorganic porous layer is various metal Sn-based plus organic ligand HQ (hydroquinone). The third artificial SEI layer is an anti-corrosion layer Al2O3.

[0152] The spatial ALD method for preparing the first artificial SEI layer includes the following steps:

[0153] In the first step, the Si negative electrode active material layer is disposed on the negative electrode current collector to obtain a pole piece.

[0154] In the second step, the pole piece obtained in the first step is placed in a spatial atomic layer deposition system. After evacuating, the isolation gas He, the precursor tetrakis(dimethylamino)tin, and the oxygen-containing reactant O3 are introduced into the spatial atomic layer deposition system in sequence or simultaneously.

[0155] In the third step, the moving mechanism is started to make the pole piece move through the deposition area of the system at least once, that is, the first layer of artificial SEI protection layer is formed.

[0156] The introduction speed of the isolation gas is 70 SLM, and the moving speed of the moving mechanism is 15 m / min.

[0157] The time-based MLD method for preparing the second artificial SEI layer includes the following steps:

[0158] In the first step, the Si negative electrode pole piece deposited with the first layer of artificial SEI layer is placed in the molecular layer deposition cavity, and the metal organic compound precursor tetrakis(diethylamino)vanadium is introduced. The precursor is chemically adsorbed on the surface layer of the negative electrode active material coated with the first layer of artificial SEI layer.

[0159] In the second step, an organic ligand is introduced into the molecular layer deposition cavity to make the organic ligand HQ (hydroquinone) react with the adsorbed precursor.

[0160] In the third step, the first step and the second step are repeated for cyclic deposition to form the second layer of artificial SEI layer.

[0161] The time-based ALD method for preparing the third artificial SEI layer includes the following steps:

[0162] In the first step, the electrode sheet deposited with the first and second artificial SEI layers is placed in an atomic layer deposition chamber, and the metal organic compound precursor aluminum ethoxide is introduced. The precursor chemisorbs on the surface of the electrode sheet coated with the second artificial SEI layer.

[0163] In the second step, an oxygen-containing reactant O2 plasma is introduced into the atomic layer deposition chamber to react the oxygen-containing reactant with the adsorbed precursor.

[0164] In the third step, the first and second steps are repeated for cyclic deposition to form the third artificial SEI anti-corrosion layer.

[0165] Example 7

[0166] As Figure 1 shown, this example provides a silicon-containing negative electrode structure, including a silicon-containing negative electrode 1, a first artificial SEI layer 2 deposited on the surface of the silicon-containing negative electrode 1 by ALD, a second artificial SEI layer 3 deposited on the surface of the first artificial SEI layer 2 by MLD, and a third artificial SEI layer 4 deposited on the second artificial SEI layer 3 by ALD.

[0167] The thickness of the first artificial SEI layer is 2 nm, the thickness of the second artificial SEI layer is 10 nm, and the thickness of the third artificial SEI layer is 4 nm.

[0168] The material of the first artificial SEI layer is manganese oxide. The material of the second artificial SEI layer is a porous organic-inorganic compound layer with a porosity of 11%. The general formula of the organic-inorganic porous layer is X-cone, where X is Mn, and the specific material of the organic-inorganic porous layer is various metal Mn-based plus organic ligand ZAO (4,4′-azobenzenedicarboxylic acid); the third artificial SEI layer is a corrosion protection layer HfO2.

[0169] The time-based ALD method for preparing the first artificial SEI layer includes the following steps:

[0170] In the first step, the Si negative electrode active material layer is disposed on the negative electrode current collector to obtain an electrode sheet.

[0171] In the second step, the electrode sheet obtained in the first step is placed in an atomic layer deposition chamber, and the metal organic compound precursor tris(2,2,6,6-tetramethyl-3,5-heptanedionato)manganese is introduced. The precursor tris(2,2,6,6-tetramethyl-3,5-heptanedionato)manganese chemisorbs on the surface of the negative electrode active material.

[0172] In the third step, an oxygen-containing reactant O2 plasma is introduced into the atomic layer deposition chamber to react the oxygen-containing reactant with the adsorbed precursor.

[0173] In the fourth step, repeat the second and third steps for cyclic deposition to form the first artificial SEI ion-conducting layer.

[0174] The spatial MLD method for preparing the second artificial SEI layer includes the following steps:

[0175] In the first step, after placing the Si negative electrode sheet deposited with the first artificial SEI layer in the molecular layer deposition chamber and evacuating it, introduce the isolation gas nitrogen, the precursor N,N'-diisopropylethylamidine manganese, and the organic ligand ZAO (4,4'-azobenzenedicarboxylic acid) into the spatial molecular layer deposition system sequentially or simultaneously.

[0176] In the second step, start the moving mechanism to move the electrode sheet through the deposition area of the system at least once, thereby forming the second artificial SEI protective layer; the introduction speed of the isolation gas is 400 SLM, and the moving speed of the moving mechanism is 40 m / min.

[0177] The spatial ALD method for preparing the third artificial SEI layer includes the following steps:

[0178] In the first step, place the electrode sheet deposited with the first and second artificial SEI layers in the spatial atomic layer deposition system, evacuate it, and then introduce the isolation gas argon, the precursor tetrakis(dimethylamino)hafnium, and the oxygen-containing reactant H2O into the spatial atomic layer deposition system sequentially or simultaneously.

[0179] In the second step, start the moving mechanism to move the electrode sheet through the deposition area of the system at least once, thereby forming the third artificial SEI protective layer.

[0180] The introduction speed of the isolation gas is 350 SLM, and the moving speed of the moving mechanism is 150 m / min.

[0181] Example 8

[0182] As Figure 1 shown, this example provides a silicon-containing negative electrode structure, including a silicon-containing negative electrode 1, a first artificial SEI layer 2 deposited on the surface of the silicon-containing negative electrode 1 by ALD, a second artificial SEI layer 3 deposited on the surface of the first artificial SEI layer 2 by MLD, and a third artificial SEI layer 4 deposited on the second artificial SEI layer 3 by ALD.

[0183] The thickness of the first artificial SEI layer is 2 nm, the thickness of the second artificial SEI layer is 16 nm, and the thickness of the third artificial SEI layer is 3 nm.

[0184] The material of the first artificial SEI layer is Li4Ti5O 12The material of the second artificial SEI layer is a porous organic-inorganic compound layer with a porosity of 27%. The general formula of the organic-inorganic porous layer is X-cone, where X is Hf. The specific material of the organic-inorganic porous layer is various metal Hf-based materials plus the organic ligand BPDC (4,4'-biphenyldicarboxylic acid); the third artificial SEI layer is a corrosion-resistant layer of zirconium fluoride.

[0185] The spatial ALD method for preparing the first artificial SEI layer includes the following steps:

[0186] First step, place the Si negative electrode active material layer on the negative electrode current collector to obtain a pole piece;

[0187] Second step, place the pole piece obtained in the first step in a spatial atomic layer deposition system. After evacuating, introduce the isolation gas nitrogen, the precursors (tetrakis(ethylmethylamino)titanium, tert-butyllithium), and the oxygen-containing reactant O3 into the spatial atomic layer deposition system in sequence or simultaneously;

[0188] Third step, start the moving mechanism to move the pole piece through the deposition area of the system at least once, that is, form the first artificial SEI protection layer;

[0189] The introduction speed of the isolation gas is 5 SLM, and the moving speed of the moving mechanism is 3 m / min.

[0190] The spatial MLD method for preparing the second artificial SEI layer includes the following steps:

[0191] First step, place the Si negative electrode pole piece deposited with the first artificial SEI layer in a molecular layer deposition cavity. After evacuating, introduce the isolation gas nitrogen, the precursor tetrakis(dimethylamino)hafnium, and the organic ligand BPDC (4,4'-biphenyldicarboxylic acid) into the spatial molecular layer deposition system in sequence or simultaneously;

[0192] Second step, start the moving mechanism to move the pole piece through the deposition area of the system at least once, that is, form the second artificial SEI protection layer;

[0193] The introduction speed of the isolation gas is 40 SLM, and the moving speed of the moving mechanism is 40 m / min.

[0194] The spatial ALD method for preparing the third artificial SEI layer includes the following steps:

[0195] First step, place the pole piece deposited with the first and second artificial SEI layers in a spatial atomic layer deposition system. After evacuating, introduce the isolation gas argon, the precursors (tetrakis(ethylmethylamino)zirconium), HF (hydrogen fluoride), NH4F (ammonium fluoride), and F2 (fluorine gas) into the spatial atomic layer deposition system in sequence or simultaneously;

[0196] In the second step, start the moving mechanism to move the pole piece through the deposition area of the system at least once, i.e., form the third artificial SEI protective layer.

[0197] Comparative Example 1

[0198] This comparative example provides a silicon-containing negative electrode structure, including a silicon-containing negative electrode and a first artificial SEI layer deposited on the surface of the silicon-containing negative electrode 1 by ALD. The thickness, material, and preparation method of the first artificial SEI layer are the same as those of the first artificial SEI layer in Example 1.

[0199] Comparative Example 2

[0200] This comparative example provides a silicon-containing negative electrode structure, including a silicon-containing negative electrode and a second artificial SEI layer deposited on the surface of the silicon-containing negative electrode 1 by MLD. The thickness, material, and preparation method of the second artificial SEI layer are the same as those of the second artificial SEI layer in Example 2.

[0201] Comparative Example 3

[0202] This comparative example provides a silicon-containing negative electrode structure, including a silicon-containing negative electrode and a third artificial SEI layer deposited on the surface of the silicon-containing negative electrode 1 by ALD. The thickness, material, and preparation method of the third artificial SEI layer are the same as those of the third artificial SEI layer in Example 3.

[0203] Comparative Example 4

[0204] This comparative example provides a silicon-containing negative electrode structure without any artificial SEI layer.

[0205] Comparative Example 5

[0206] This comparative example provides a silicon-containing negative electrode structure, including a silicon-containing negative electrode, a first artificial SEI layer deposited on the surface of the silicon-containing negative electrode by ALD, and a second artificial SEI layer deposited on the surface of the first artificial SEI layer by MLD. The thickness, material, and preparation method of the first artificial SEI layer and the second artificial SEI layer are the same as those of the first artificial SEI layer and the second artificial SEI layer in Example 1.

[0207] Comparative Example 6

[0208] This comparative example provides a silicon-containing negative electrode structure, including a silicon-containing negative electrode, a first artificial SEI layer deposited on the surface of the silicon-containing negative electrode by ALD, and a third artificial SEI layer deposited on the surface of the first artificial SEI layer by ALD. The thickness, material, and preparation method of the first artificial SEI layer and the third artificial SEI layer are the same as those of the first artificial SEI layer and the third artificial SEI layer in Example 1.

[0209] Comparative Example 7

[0210] This comparative example provides a silicon-containing negative electrode structure, including a silicon-containing negative electrode, a second artificial SEI layer deposited on the surface of the silicon-containing negative electrode by MLD, and a third artificial SEI layer deposited on the surface of the second artificial SEI layer by ALD. The thickness, material, and preparation method of the second artificial SEI layer and the third artificial SEI layer are the same as those of the second artificial SEI layer and the third artificial SEI layer in Example 1.

[0211] The cycle data of Examples 1-8 and Comparative Examples 1-7 were tested. The specific method for testing the cycle performance was as follows:

[0212] A half-cell composed of a pure Si electrode and Li metal was subjected to a long cycle test under 0.2C. The cycle life and capacity retention rate after 500 cycles are shown in the following table.

[0213] Table 2: Cycle data table for each group

[0214]

[0215] It can be seen from the above table that the cycle life and capacity retention rate of the three-layer structure are significantly higher than those of the double-layer and single-layer structures. At the same time, with the increase in the thickness of the intermediate layer, the cycle life shows an increasing trend, but the capacity retention rates are not much different. Thanks to the ingenious design of the three-layer structure, it can match the severe volume expansion of the Si negative electrode during cycling, maintain the structural stability of the negative electrode, and thus extend the cycle life and capacity retention rate of the battery.

[0216] Based on the disclosure and teachings of the above specification, those skilled in the art to which the present invention pertains can also make changes and modifications to the above embodiments. Therefore, the present invention is not limited to the specific embodiments disclosed and described above, and some modifications and changes to the present invention should also fall within the protection scope of the claims of the present invention. In addition, although some specific terms are used in this specification, these terms are only for convenience of description and do not constitute any limitation to the present invention.

Claims

1. A silicon-containing negative electrode structure, characterized in that: The invention comprises a silicon-containing negative electrode, a first artificial SEI layer deposited on the surface of the silicon-containing negative electrode by ALD, a second artificial SEI layer deposited on the surface of the first artificial SEI layer by MLD, and a third artificial SEI layer deposited on the second artificial SEI layer by ALD.

2. The silicon-containing negative electrode structure according to claim 1, characterized in that: The thickness of the first artificial SEI layer is 1-5 nm, the thickness of the second artificial SEI layer is 1-20 nm, and the thickness of the third artificial SEI layer is 1-5 nm.

3. The silicon-containing negative electrode structure according to claim 1, characterized in that: The material of the first artificial SEI layer is oxide or solid electrolyte ion-conducting material.

4. The silicon-containing negative electrode structure according to claim 3, characterized in that: The general chemical formula of the oxide is MOx, where M is at least one of Al, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Y, Zr, Nb, Mo, Ru, La, Ce, Hf, Ta, W, Mg, In, Sn and Si, and 1≤x≤5. The chemical formula of the solid electrolyte ion conductor is Li x A3B2O 12 wherein A is at least one of Y, Pr, Nd, and La, wherein B is at least one of Te, Nb, Ta, Sb, Zr, Sn, and Hf, wherein 1≤x≤7; The solid electrolyte ion-conducting material is specifically Li3Y3Te2O 12 , Li3Pr3Te2O 12 , Li3Nd3Te2O 12 , Li5La3Ta2O 12 ,Li5La3Nb2O 12 ,Li5La3Sb2O 12 ,Li5Nd3Sb2O 12 ,Li6MgLa2Ta2O 12 ,Li6CaLa2Ta2O 12 ,Li6BaLa2Ta2O 12 , Li6BaLa2Nb2O 12 ,Li7La3Sn2O 12 ,Li7La3Zr2O 12 , Li7La3Hf2O 12 , LiTiO2, LiAlO2, LiZrO, LiCeO2, LiMnO2, LiBO2, LiTaO3, Li2TiO3, Li2SiO3, Li2ZrO3, Li2CO3, Li4Ti5O 12 , at least one of Li5AlO4.

5. The silicon-containing negative electrode structure according to claim 1, characterized in that: The material of the second artificial SEI layer is a porous organic-inorganic compound layer with a porosity of 10%-30%. The general formula of the organic-inorganic porous layer is X-cone, wherein X is at least one of Al, Zn, Ti, Zr, Hf, V, Sn, Mn, and Li. The specific material of the organic-inorganic porous layer is various metal X groups plus organic ligands, wherein the organic ligands are at least one of EG (ethylene glycol), GL (glycerol), TPA (terephthalic acid), Li2TP (lithium terephthalate), THD, (2,2,6,6-tetramethyl-3,5-heptanedioate), TPA-NH2-2 (aminophthalic acid), PDC (pyridinedicarboxylic acid), NDC-2,6- (naphthalene dicarboxylic acid), BPDC (4,4′-biphenyl dicarboxylic acid), ZAO (4,4′-azobenzene dicarboxylic acid), HQ (hydroquinone) and PD (propylene glycol).

6. The silicon-containing negative electrode structure according to claim 1, characterized in that: The third artificial SEI layer is an anti-corrosion layer, and the anti-corrosion layer is at least one of ZrO2, HfO2, Al2O3 and fluoride AFx, wherein A is one of Li, Al, Sc, Zr, La, Sm, Ce and Bi, and 1≤x≤4.

7. The silicon-containing negative electrode structure according to claim 1, characterized in that: The first artificial SEI layer and the third artificial SEI layer are prepared by time-type ALD or space-type ALD, and the second artificial SEI layer is prepared by time-type MLD or space-type MLD.

8. The silicon-containing negative electrode structure according to claim 7, characterized in that: The time-based ALD method for preparing the first artificial SEI layer comprises the following steps: The first step is to place the Si negative electrode active material layer on the negative electrode current collector to obtain a pole piece; In the second step, the electrode obtained in the first step is placed in an atomic layer deposition chamber, and a metal organic compound precursor and / or a silicon-containing organic compound is introduced, and the precursor is chemically adsorbed on the surface of the negative electrode active material; The third step is to introduce an oxygen-containing reactant into the atomic layer deposition chamber to allow the oxygen-containing reactant to react with the adsorbed precursor; Step 4: repeat the second and third steps, cyclically deposit, to form the first artificial SEI ion-conducting layer; The oxygen-containing reactant is H2O, O3 or O2 plasma. The spatial ALD method for preparing the first artificial SEI layer comprises the following steps: The first step is to place the Si negative electrode active material layer on the negative electrode current collector to obtain a pole piece; The second step is to place the electrode obtained in the first step in a space-type atomic layer deposition system, and after evacuation, introduce the isolation gas, precursor, and oxygen-containing reactant into the space-type atomic layer deposition system in sequence or simultaneously; The third step is to start the moving mechanism to move the electrode through the deposition area of ​​the system at least once, thus forming the first artificial SEI protective layer; The oxygen-containing reactant is H2O, O3 or oxygen plasma; the isolation gas is N2, He or Ar; The introduction speed of the isolation gas is 0.1-500SLM, the moving speed of the moving mechanism is 0.01-300m / min, the precursor is a metal organic compound and / or a silicon-containing organic matter, wherein the silicon-containing substance is specifically at least one of bis(diethylamino)silane, tetra(ethylmethylamino)silane, trimethoxysilanol, diisopropylaminosilane and bis(tert-butylamino)silane.

9. The silicon-containing negative electrode structure according to claim 7, characterized in that: The time-based MLD method for preparing the second artificial SEI layer comprises the following steps: In the first step, a Si negative electrode sheet with a first artificial SEI layer deposited thereon is placed in a molecular layer deposition chamber, and a metal organic compound precursor is introduced, and the precursor is chemically adsorbed on the surface of the negative electrode active material coated with the first artificial SEI layer; The second step is to introduce organic ligands into the molecular layer deposition chamber to allow the organic ligands to react with the adsorbed precursors; In the third step, the first and second steps are repeated, and the deposition is cyclic to form a second artificial SEI layer; The organic ligand is at least one of ethylene glycol, glycerol, terephthalic acid, lithium terephthalate, 2,2,6,6-tetramethyl-3,5-heptanedioate, aminophthalic acid, pyridine dicarboxylic acid, 2,6-(naphthalene dicarboxylic acid), 4,4′-biphenyl dicarboxylic acid), 4,4′-azobenzene dicarboxylic acid, hydroquinone and propylene glycol; The spatial MLD method for preparing the second artificial SEI layer comprises the following steps: In the first step, the Si negative electrode sheet with the first artificial SEI layer is placed in a molecular layer deposition chamber and evacuated, and then the isolation gas, precursor, and organic ligand are introduced into the spatial molecular layer deposition system in sequence or simultaneously; The second step is to start the moving mechanism to move the electrode through the deposition area of ​​the system at least once, so as to form a second artificial SEI protective layer; the isolation gas is N2, He or Ar; The introduction speed of the isolation gas is 0.1-500SLM, the moving speed of the moving mechanism is 0.01-300m / min, the precursor is a metal organic compound and / or a silicon-containing organic matter, wherein the silicon-containing substance is specifically at least one of bis(diethylamino)silane, tetra(ethylmethylamino)silane, trimethoxysilanol, diisopropylaminosilane and bis(tert-butylamino)silane; the organic ligand is at least one of ethylene glycol, glycerol, terephthalic acid, lithium terephthalate, 2,2,6,6-tetramethyl-3,5-heptanedioate, aminophthalic acid, pyridinedicarboxylic acid, 2,6-(naphthalene dicarboxylic acid), 4,4′-biphenyl dicarboxylic acid), 4,4′-azobenzene dicarboxylic acid, hydroquinone and propylene glycol.

10. The silicon-containing negative electrode structure according to claim 7, characterized in that: The time-based ALD method for preparing the third artificial SEI layer comprises the following steps: In the first step, the electrode with the first and second artificial SEI layers deposited thereon is placed in an atomic layer deposition chamber, and a metal organic compound precursor is introduced, and the precursor is chemically adsorbed on the surface of the electrode coated with the second artificial SEI layer; The second step is to introduce an oxygen-containing reactant or a fluorine-containing compound into the atomic layer deposition chamber to allow the oxygen-containing reactant to react with the adsorbed precursor; Step 3: Repeat the first and second steps, cyclically deposit, to form a third artificial SEI anti-corrosion layer; The oxygen-containing reactant is H2O, O3 or O2 plasma; the fluorine-containing compound is at least one of HF (hydrogen fluoride), NH4F (ammonium fluoride) and F2 (fluorine gas); The spatial ALD method for preparing the third artificial SEI layer comprises the following steps: The first step is to place the electrode with the first and second artificial SEI layers deposited thereon in a space-type atomic layer deposition system, and after evacuation, introduce an isolation gas, a precursor, an oxygen-containing reactant or a fluorine-containing compound into the space-type atomic layer deposition system in sequence or simultaneously; The second step is to start the moving mechanism to move the electrode through the deposition area of ​​the system at least once, thus forming the third artificial SEI protective layer. The oxygen-containing reactant is H2O, O3 or oxygen plasma; the fluorine-containing compound is at least one of HF (hydrogen fluoride), NH4F (ammonium fluoride) and F2 (fluorine gas); The isolation gas is N2, He or Ar; the introduction speed of the isolation gas is 0.1-500SLM, the moving speed of the moving mechanism is 0.01-300m / min, and the precursor is a metal organic compound and / or a silicon-containing organic matter, wherein the silicon-containing substance is specifically at least one of bis(diethylamino)silane, tetra(ethylmethylamino)silane, trimethoxysilanol, diisopropylaminosilane and bis(tert-butylamino)silane.

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