Silicon-carbon negative electrode pre-lithiation method using magnetron sputtering technology and application of silicon-carbon negative electrode pre-lithiation method

Abstract

The invention belongs to the technical field of electrochemical energy storage, and relates to a silicon-carbon negative electrode pre-lithiation method using a magnetron sputtering technology and application, and the method comprises the steps of silicon-carbon negative electrode piece preparation, magnetron sputtering pre-lithiation, artificial interface layer construction, cooling and packaging. The lithium nano layer and the artificial interface layer are sequentially deposited on the surface of the silicon-carbon negative electrode through winding type magnetron sputtering equipment, so that integrated construction of pre-lithiation and interface stability is realized; the initial coulombic efficiency of the silicon-carbon negative electrode is improved to 90% or above, the cycle life is remarkably prolonged, and the silicon-carbon negative electrode is suitable for a liquid / all-solid-state battery; according to the invention, the problems of high initial irreversible capacity and poor interface stability of the silicon-carbon negative electrode are solved by inhibiting side reaction and buffering volume expansion through the artificial interface layer and combining high uniformity and expandability of magnetron sputtering, and an efficient and reliable technical path is provided for industrial production of the high-energy-density lithium ion battery.

Description

Technical Field

[0001] The present invention belongs to the technical field of electrochemical energy storage, and relates to a silicon-carbon negative electrode pre-lithiation method using magnetron sputtering technology and its application. Background Art

[0002] Silicon-carbon anodes, due to their extremely high theoretical specific capacity and abundant resource reserves, have become potential anode materials for next-generation high-energy-density lithium-ion batteries. However, a key challenge facing their application is the high initial irreversible capacity. This high initial irreversible capacity is primarily due to the formation of a solid electrolyte interface (SEI) and the occurrence of interfacial side reactions during the initial charge and discharge cycles of the silicon-carbon anode, processes that consume a large amount of lithium ions. Furthermore, silicon expands by up to 300% during lithium insertion and removal, further rendering some lithium unrecyclable. These factors result in the initial coulombic efficiency of silicon-carbon anodes being significantly lower than that of traditional graphite anodes, typically below 90%. This severely limits the battery's capacity compatibility and energy density, and thus impacts the actual performance of the entire battery. To address this issue, pre-lithiation technology has emerged as an indispensable solution. By pre-introducing lithium ions during the anode manufacturing process, pre-lithiation can effectively compensate for the lithium consumed by SEI formation and side reactions during the first cycle, significantly improving the initial coulombic efficiency to over 95%. This not only optimizes the lithium ion balance between the positive and negative electrodes and increases the battery's energy density, but also reduces side reactions in subsequent cycles and improves long-term cycle performance. At the same time, pre-lithiation can enhance the structural stability of the silicon-carbon negative electrode by optimizing the surface state, thereby extending the battery's life.

[0003] However, the existing process for pre-lithiation of the negative electrode has problems such as low uniformity, low first coulombic efficiency, weak process controllability and consistency.

[0004] Therefore, an efficient, safe and industrializable negative electrode pre-lithiation method is needed to solve the above technical problems. Summary of the Invention

[0005] The technical solution adopted by the present invention to solve the technical problem is: a method for pre-lithiation of a silicon-carbon negative electrode using magnetron sputtering technology, comprising the following steps:

[0006] Step 1: Preparation of silicon-carbon negative electrode sheet, using solution coating, cold pressing, and roller pressing process to prepare the negative electrode substrate. The active material layer of the silicon-carbon negative electrode sheet includes: silicon-carbon negative electrode material (such as nano-Si, SiO x , Si / C composite), a conductive agent, and a binder to form a silicon-carbon composite layer;

[0007] Step 2: Magnetron sputtering pre-lithiation: The silicon-carbon negative electrode sheet prepared in step 1 is placed on a conveyor belt in a winding magnetron reactive sputtering device. Under high vacuum conditions, lithium is deposited on the silicon-carbon negative electrode sheet using a metal lithium target to form a nano-lithium layer.

[0008] Step 3: constructing an artificial interface layer. The target material is replaced with at least one of LiF, Li3N, and Li2O. Reactive magnetron sputtering is used to continue depositing an artificial interface layer on the surface of the nanolithium layer. This interface layer can regulate the diffusion behavior of lithium ions, inhibit side reactions, and enhance interface stability.

[0009] Step 4: Cooling and packaging. After the deposition is completed, cool to room temperature to obtain a silicon-carbon negative electrode material with a pre-lithiation layer and an artificial interface layer.

[0010] Preferably, in step 1, the silicon-carbon negative electrode material is made by mixing silicon-based materials and graphite-based materials; the silicon-based materials include: nano-silicon, micron-silicon, and silicon oxide; the graphite-based materials include: natural graphite materials, artificial graphite materials, mesophase carbon microbeads, amorphous porous carbon, biomass carbon, and graphene; the mass ratio of silicon-based materials to graphite-based materials in the silicon-carbon negative electrode material is 10-50:90-50.

[0011] Preferably, in step 1, the preparation step of the silicon-carbon composite layer includes: dispersing the silicon-carbon negative electrode material, the conductive additive, and the polymer adhesive in water, and then coating the mixed slurry on the metal substrate and drying it; the mass ratio of the silicon-carbon negative electrode material, the conductive additive, and the polymer adhesive is 85-95:3-8:3-8; the polymer adhesive includes a mixture of polyacrylic acid and polyvinyl alcohol, and the mass ratio of polyacrylic acid to polyvinyl alcohol is 5-50:95-50.

[0012] Preferably, in step 2, the deposition thickness of the nanolithium layer is 200 to 800 nm; and in step 3, the deposition thickness of the artificial interface layer is 20 to 100 nm.

[0013] Preferably, during the magnetron sputtering process, the vacuum degree of the magnetron sputtering is 9.9×10 -5 ~50×10 -5 Pa, target distance is 20-50 cm, sputtering temperature is 20-30°C, and winding / unwinding speed of the winding roller is 5-10 rpm.

[0014] The present invention also discloses an application of a silicon-carbon negative electrode pre-lithiation method using magnetron sputtering technology, which is used to prepare lithium-ion batteries using the above-mentioned silicon-carbon negative electrode pre-lithiation method. The lithium batteries include liquid lithium-ion batteries and all-solid-state lithium-ion batteries; the positive electrode materials of the lithium batteries include: lithium cobalt oxide, lithium nickel manganese cobalt oxide, lithium nickel aluminum cobalt oxide or lithium-rich manganese-based materials.

[0015] Preferably, the preparation process of the positive electrode comprises the following steps: stirring and dispersing the positive electrode material, Super-P conductive agent and polyvinylidene fluoride in a solvent at a mass ratio of 85-95:3-8:3-8 to form a positive electrode slurry with a viscosity of 1 Pa·s to 10 Pa·s, scraping the positive electrode slurry onto the surface of the aluminum foil substrate, and rolling it after drying to prepare a positive electrode sheet with a surface loading of 1 mAh / cm 2 ~5mAh / cm 2 .

[0016] Preferably, in the electrolyte of the liquid lithium-ion battery, the lithium salt includes one or more of lithium bis(trifluoromethylsulfonyl)amide, lithium bis(fluorosulfonyl)imide, and lithium hexafluorophosphate; the solvent includes an equal volume mixture of dimethyl carbonate, diethyl carbonate, and ethyl methyl carbonate; the additive includes fluoroethylene carbonate, and the lithium salt concentration of the electrolyte is 1 to 4 mol / L.

[0017] Preferably, the solid electrolyte of the all-solid-state lithium-ion battery includes: sulfide solid electrolyte, halide solid electrolyte; sulfide solid electrolyte includes: Li2S-P2S5, Li 10 GeP2S 12 、Li7P3S 11 , Li2S-Sb2S3; the halide solid electrolyte includes: Li3MX6 (M=Y, Er, Sc, In, X=F, Cl, Br), Li2MCl6 (M=Zr, Cd, Ti); the preparation method of the solid electrolyte is a 200-400MPa static pressure method.

[0018] More preferably, the positive electrode preparation process of the lithium battery includes the following steps: the positive electrode material, the sulfide solid electrolyte and the conductive agent are uniformly dispersed in a mass ratio of (60-80): (30-10): 10, spread on the solid electrolyte, and prepared by a static pressure method of 200-400 MPa.

[0019] The beneficial effects of the present invention are:

[0020] 1. The pre-lithiation method of the present invention has high uniformity: magnetron sputtering is a physical vapor deposition method with a stable deposition rate and uniform layer thickness. It can achieve precise control of the lithium layer and the interface layer, improve the problem of uneven interface between the silicon-carbon negative electrode, and enhance the interface consistency and ion transmission efficiency.

[0021] 2. The lithium battery prepared by the method of the present invention has a high first coulombic efficiency. The pre-lithiation layer can effectively compensate for the lithium loss caused by electrolyte decomposition, SEI film formation, etc., so that the first coulombic efficiency of the lithium battery negative electrode is increased by ≥20%, thereby improving the overall battery energy density.

[0022] 3. The lithium battery prepared by the method of the present invention has a long cycle life, a dense artificial interface layer structure, good chemical stability, can stabilize the lithium / silicon-carbon interface, reduce lithium dendrite formation and side reactions, delay the pulverization of active materials and interface failure problems, and extend the battery cycle life by more than 500 cycles (80% capacity retention).

[0023] 4. The process scalability of the method of the present invention is strong. The winding magnetron sputtering process is suitable for continuous large-area deposition. The process parameters are highly adjustable and have good controllability and consistency. It is suitable for industrial production lines of lithium-ion batteries and has the ability to prepare high-energy-density batteries. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 This is a structural schematic diagram of the silicon-carbon negative electrode pre-lithiation method and application based on magnetron sputtering technology of the present invention. DETAILED DESCRIPTION

[0025] The following will provide a clear and complete description of the relevant technologies in the present invention in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of them. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0026] The method for preparing a silicon-carbon negative electrode by magnetron sputtering pre-lithiation in this embodiment comprises the following steps:

[0027] Step 1: Prepare a negative electrode slurry using a silicon-carbon negative electrode as the active material using the following component ratios: a 90:5:5 mass ratio of the silicon-carbon negative electrode material to the conductive additive and polymer binder; and a 5-50:95-50 mass ratio of the polymer binder to the polyvinyl alcohol mixture. Stir the above materials in deionized water for 12 hours to form a uniform slurry, which is then coated onto a copper foil current collector, dried using hot air at 120°C for 30 minutes, and then rolled using a double-roller to a thickness of approximately 50 μm.

[0028] Step 2. Parameter configuration of magnetron sputtering equipment: Use a winding magnetron reactive sputtering equipment, which includes: a vacuum chamber with an ultimate vacuum degree of ≤5×10-4Pa; a negative electrode clamping system that can move during the sputtering process to achieve uniform deposition; two sets of target positions, each equipped with a metal lithium target (99.9%) and an interface layer target (such as LiF or Li3N); a control system that can adjust key process parameters such as gas pressure, power, and bias.

[0029] Step 3: Pre-lithiation layer deposition process: Place the dried negative electrode sheet into the sputtering chamber and perform the following steps: vacuum to 5.0×10 -4Pa, high-purity Ar gas (99.999%) was introduced to maintain the pressure at about 0.5 Pa; the power density of lithium target magnetron sputtering was 0.8 W / cm 2 (DC), target-substrate distance: 100 mm, sputtering time: 10-30 min (corresponding to a lithium layer thickness of approximately 200-800 nm). The resulting metallic lithium is uniformly deposited on the silicon-carbon surface, forming a pre-lithiation layer of controllable thickness.

[0030] Step 4: Artificial interface layer deposition process: Without changing the vacuum conditions, switch the target material to LiF and continue sputtering the LiF ceramic target. The power density is 1.0W / cm 2 (RF), sputtering atmosphere: Ar / O2 mixed gas (volume ratio 95:5), total pressure 0.8 Pa; sputtering time: 3-10 minutes, resulting in an interfacial layer thickness of 10-50 nm. This interfacial layer serves as a SEI film and also inhibits subsequent electrolyte decomposition reactions.

[0031] Step 5: After the deposition is completed, turn off the power and cool to room temperature. Take out the negative electrode sheet under an inert atmosphere (argon) and seal it in a vacuum sealed bag for storage.

[0032] Step 6: Prepare a liquid electrolyte, wherein the lithium salt is one or more of lithium bis(trifluoromethylsulfonyl)amide, lithium bis(fluorosulfonyl)imide, and lithium hexafluorophosphate; the solvent is a mixture of equal volumes of dimethyl carbonate, diethyl carbonate, and ethyl methyl carbonate; the additive is fluoroethylene carbonate, and the lithium salt concentration of the electrolyte is 1 to 4 mol / L.

[0033] Step 7: Assemble the pre-lithiated negative electrode, the lithium metal counter electrode, and the liquid electrolyte into a battery, and test its electrochemical performance at room temperature.

[0034] Step 8: Stir and disperse one of the positive electrode materials, lithium cobalt oxide, lithium nickel manganese cobalt oxide, lithium nickel aluminum cobalt oxide or lithium-rich manganese-based materials, Super-P conductive agent and polyvinylidene fluoride in a solvent at a mass ratio of 90:5:5 to form a positive electrode slurry with a viscosity of 1 Pa·s to 10 Pa·s. The positive electrode slurry is scraped onto the surface of the aluminum foil substrate, and after drying, it is rolled to prepare a positive electrode sheet. The prepared positive electrode surface loading is 1 to 5 mAh / cm 2 The pre-lithiated negative electrode, positive electrode and liquid electrolyte were assembled into a battery, and its electrochemical performance was tested at room temperature.

[0035] Step 9: Using a static pressure of 200-400 MPa, the solid electrolyte is a sulfide solid electrolyte Li2S-P2S5, Li 10 GeP2S 12 ,Li7P3S 11The pre-lithiated anode, cathode, and solid electrolyte were assembled into a solid-state battery, and the electrochemical performance was tested at room temperature.

[0036] The present invention forms a pre-lithiation layer with stable structure and continuous interface by sputtering metallic lithium target and functional interface layer target on the surface of silicon-carbon negative electrode in sequence, which effectively compensates for the irreversible capacity loss of negative electrode material during the first charge and discharge process, and significantly improves the first coulombic efficiency and cycle stability of silicon-carbon negative electrode.

[0037] By using a magnetron sputtering process to deposit the lithium layer and the interface layer in situ in a controllable manner, the present invention overcomes the common problems of uneven distribution, violent reaction, and unstable structure in existing pre-lithiation methods, ensuring good physical adhesion and chemical interface coordination between the lithium layer and the silicon-carbon substrate, and improving the overall consistency and electrochemical performance of the electrode.

[0038] The magnetron reactive sputtering process adopted in the present invention has good scalability and industrial adaptability, is suitable for continuous winding deposition, and can be widely used in the electrode pretreatment links of lithium-ion batteries and solid-state batteries, realizing a smooth transition from laboratory scale to industrial scale.

[0039] Compared with the traditional chemical contact pre-lithiation method, the present invention avoids the use of flammable organic solvents and highly active lithium sources while achieving the pre-lithiation goal, improves process safety, has higher environmental friendliness and operational convenience, and is suitable for large-scale green manufacturing.

[0040] Therefore, the method described in the present invention not only improves the initial performance of the silicon-carbon negative electrode, but also provides a feasible and reliable technical path for the industrial production of high-energy density and long cycle life lithium batteries, and has broad application prospects and market promotion value.

[0041] Example

[0042] Example 1: Pre-lithiation silicon-carbon anode Li-SiOx / C

[0043] The dried silicon-carbon negative electrode sheet was placed in a winding magnetron sputtering system. A metal lithium target with a purity of 99.99% was installed at the target position, and the distance between the target and the substrate was controlled to be 8 cm. The system was vacuumed to 5.0×10 -4After the pressure dropped below 0.5 Pa, high-purity argon (99.999%) was introduced as the working gas. The operating pressure was maintained at 0.5 Pa, the RF power was set to 80 W, the sputtering time was 10 minutes, and the lithium layer thickness was controlled to approximately 200 nm. After deposition, the electrode was removed and encapsulated in an inert atmosphere to obtain a pre-lithiated silicon-carbon anode. Tests showed that the electrode's initial coulombic efficiency increased from the original 75.2% to 91.3%.

[0044] Example 2: Pre-lithiation silicon-carbon anode Li3N / Li-SiOx / C with Li3N interface layer

[0045] The dried silicon-carbon negative electrode sheet was placed in a winding magnetron sputtering system. A metallic lithium target with a purity of 99.99% was installed at the target position, and the distance between the target and the substrate was controlled to be 10 cm. The system was vacuumed to 5.0×10 -4 After the pressure drops below 0.8 Pa, high-purity argon (99.999%) is introduced as the working gas, the working pressure is maintained at 0.5 Pa, the RF power is set to 80 W, the sputtering time is 10 min, and the thickness of the lithium layer is controlled at about 200 nm. Subsequently, nitrogen is further introduced as the reaction atmosphere. A metallic lithium target is selected, and reactive sputtering is carried out in an Ar / N2 mixed atmosphere (volume ratio 4:1). The working pressure is maintained at 0.8 Pa, the sputtering power is set to 70 W, and the sputtering time is 8 min. The reaction conditions are controlled to form a Li3N interface layer of about 50 nm thick, which provides excellent interface lithium conductivity and stability during battery cycling. The cycle test results show that the interface layer significantly reduces the interface impedance and improves the capacity retention rate of the silicon-carbon negative electrode at high rates.

[0046] Example 3: Pre-lithiated silicon-carbon anode with LiF interface layer LiF / Li-SiOx / C

[0047] The dried silicon-carbon negative electrode sheet was placed in a winding magnetron sputtering system. A metal lithium target with a purity of 99.99% was installed at the target position, and the distance between the target and the substrate was controlled to be 8 cm. The system was vacuumed to 5.0×10 -4 Pa, high-purity argon (99.999%) is introduced as the working gas, the working pressure is maintained at 0.5Pa, the RF power is set to 80W, the sputtering time is 10min, and the thickness of the lithium layer is controlled at about 200nm. A metallic lithium target is selected, and reactive sputtering is carried out under the conditions of Ar / CF4 mixed gas (volume ratio 5:1). The sputtering power is 60W, and the reaction time is 6min, forming a LiF interface layer with a thickness of about 60nm. This layer has a dense structure and excellent ion conductivity, which can effectively inhibit side reactions and stabilize the SEI film. The pre-lithiation negative electrode prepared under this embodiment shows excellent cycle stability, and the capacity retention rate is still 89.4% after 650 cycles.

[0048] Example 4: Li-Mg composite pre-lithiated silicon-carbon anode Li-Mg / Li-SiOx / C

[0049] A dual-target magnetron system was set up, with one target being metallic lithium (99.9%) and the other being metallic magnesium (99.99%). The power was set to 80W (lithium) and 50W (magnesium), respectively, and a DC-RF hybrid sputtering method was adopted. The total sputtering time was 10 minutes, forming a Li-Mg alloy film with a thickness of about 300nm. This alloy layer can synergistically regulate the deposition behavior of lithium in subsequent cycles, inhibit dendrite growth, and improve interface safety. The electrode had an initial coulombic efficiency of up to 93.5%, and had good rate performance and thermal stability.

[0050] Example 5: Gradient pre-lithiation design of LiPON / Li-SiOx / C using LiPON interface buffer layer

[0051] The dried silicon-carbon negative electrode sheet was placed in a winding magnetron sputtering system. A metal lithium target with a purity of 99.9% was installed at the target position, and the distance between the target and the substrate was controlled to be 8 cm. The system was evacuated to 5.0×10 -4 Pa, high-purity argon (99.999%) is introduced as the working gas, the working pressure is maintained at 0.5Pa, the RF power is set to 80W, the sputtering time is 10min, and the thickness of the lithium layer is controlled at about 200nm. Subsequently, RF sputtering technology is used to deposit a LiPON buffer layer with a thickness of about 100nm on the surface of the silicon-carbon negative electrode (the target material is Li3PO4+N2 reaction atmosphere) to form a dense electronically insulating and ion-conducting intermediate layer. The design of this gradient structure can effectively buffer the volume expansion and stabilize the lithium-silicon interface. This structural system exhibits extremely high interface stability, and the capacity retention rate is maintained at more than 90% after 890 consecutive cycles.

[0052] Example 6: LiPON+LiF composite interface pre-lithiation silicon-carbon anode LiPON+LiF / Li-SiOx / C

[0053] The dried silicon-carbon negative electrode sheet was placed in a winding magnetron sputtering system. A metal lithium target with a purity of 99.99% was installed at the target position, and the distance between the target and the substrate was controlled to be 8 cm. The system was vacuumed to 5.0×10 -4After the pressure drops below 0.5 Pa, high-purity argon (99.999%) is introduced as the working gas, the working pressure is maintained at 0.5 Pa, the RF power is set to 80W, the sputtering time is 10min, and the thickness of the lithium layer is controlled at about 200nm. A metal lithium target is selected, and reactive sputtering is carried out under Ar / CF4 mixed gas (volume ratio 5:1). The sputtering power is 60W, the reaction time is 6min, and a LiF interface layer with a thickness of about 60nm is formed. This layer has a dense structure and excellent ion conductivity, which can effectively inhibit side reactions and stabilize the SEI film. Subsequently, a LiPON buffer layer with a thickness of about 100nm is deposited on the surface of the silicon-carbon negative electrode by RF sputtering technology (the target material is Li3PO4+N2 reaction atmosphere), forming a dense electronically insulating and ion-conductive intermediate layer. The design of this gradient structure can effectively buffer the volume expansion and stabilize the lithium-silicon interface. This structural system exhibits extremely high interface stability, and the capacity retention rate is maintained at more than 89% after 700 consecutive cycles.

[0054] Table 1

[0055]

[0056] As shown in Table 1, the first coulombic efficiency of the silicon-carbon anode treated in this embodiment increased from the traditional approximately 75% to over 90%, effectively reducing energy density loss while ensuring high specific capacity. Furthermore, the introduced functional interface layers (such as LiF, Li3N, and LiPON) inhibit side reactions and buffer volume changes during the electrochemical cycle, enhancing interface stability and slowing structural degradation, thereby significantly extending the battery's service life.

[0057] In summary, the present invention uses a winding magnetron sputtering device to sequentially deposit a lithium nanolayer and an artificial interface layer on the surface of the silicon-carbon negative electrode, thereby realizing the integrated construction of pre-lithiation and interface stabilization; the silicon-carbon negative electrode is composed of a silicon-based material (nano-silicon, silicon oxide, etc.) and a graphite-based material in a composite material according to a mass ratio, and the electrode substrate is prepared by coating and drying; the magnetron sputtering process parameters can accurately control the structure of the lithium layer and the interface layer. The present invention increases the initial coulomb efficiency of the silicon-carbon negative electrode to more than 90%, significantly extends the cycle life, and is suitable for liquid / all-solid-state batteries. By suppressing side reactions and buffering volume expansion through the artificial interface layer, combined with the high uniformity and scalability of magnetron sputtering, the problems of high initial irreversible capacity and poor interface stability of the silicon-carbon negative electrode are solved, providing an efficient and reliable technical path for the industrial production of high-energy-density lithium-ion batteries.

[0058] It should be emphasized that the above are only preferred embodiments of the present invention and do not limit the present invention in any form. Any simple modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention are still within the scope of the technical solution of the present invention.

Claims

1. A method for pre-lithiation of a silicon-carbon negative electrode using magnetron sputtering technology, characterized in that: The following steps are involved: Step 1: Preparation of silicon-carbon negative electrode sheet: using solution coating, cold pressing, and roller pressing processes to prepare the negative electrode substrate. The active material layer of the silicon-carbon negative electrode sheet includes: a silicon-carbon composite layer formed by mixing silicon-carbon negative electrode material, conductive agent, and binder; Step 2: Magnetron sputtering pre-lithiation: The silicon-carbon negative electrode sheet prepared in step 1 is placed in a winding magnetron reactive sputtering device. Under high vacuum conditions, lithium is deposited on the silicon-carbon negative electrode sheet using a metal lithium target to form a nano-lithium layer. Step 3: constructing an artificial interface layer, replacing the target material with at least one of LiF, Li3N, and Li2O, and using reactive magnetron sputtering to continue depositing on the surface of the nanolithium layer to form an artificial interface layer; Step 4: Cooling and packaging. After the deposition is completed, cool to room temperature to obtain a silicon-carbon negative electrode material with a pre-lithiation layer and an artificial interface layer.

2. The method for pre-lithiation of a silicon-carbon negative electrode using magnetron sputtering technology according to claim 1, characterized in that: In step 1, the silicon-carbon negative electrode material is made by mixing silicon-based materials and graphite-based materials; the silicon-based materials include: nano-silicon, micron-silicon, and silicon oxide; the graphite-based materials include: natural graphite materials, artificial graphite materials, mesophase carbon microbeads, amorphous porous carbon, biomass carbon, and graphene; the mass ratio of silicon-based materials to graphite-based materials in the silicon-carbon negative electrode material is 10-50:90-50.

3. The method for pre-lithiation of a silicon-carbon negative electrode using magnetron sputtering technology according to claim 1, characterized in that: In step 1, the preparation step of the silicon-carbon composite layer includes: dispersing a silicon-carbon negative electrode material, a conductive additive, and a polymer adhesive in water, and then coating the mixed slurry on a metal substrate and drying it; the mass ratio of the silicon-carbon negative electrode material, the conductive additive, and the polymer adhesive is 85-95:3-8:3-8; the polymer adhesive includes a mixture of polyacrylic acid and polyvinyl alcohol, and the mass ratio of the polyacrylic acid to the polyvinyl alcohol is 5-50:95-50.

4. The method for pre-lithiation of a silicon-carbon negative electrode using magnetron sputtering technology according to claim 1, wherein: In the step 2, the deposition thickness of the nanolithium layer is 200 to 800 nm; in the step 3, the deposition thickness of the artificial interface layer is 20 to 100 nm.

5. The method for pre-lithiation of a silicon-carbon negative electrode using magnetron sputtering technology according to claim 1, characterized in that: During the magnetron sputtering process, the vacuum degree of the magnetron sputtering was 9.9×10 -5 ~50×10 -5 Pa, target distance is 20-50 cm, sputtering temperature is 20-30°C, and winding / unwinding speed of the winding roller is 5-10 rpm.

6. An application of a silicon-carbon negative electrode pre-lithiation method using magnetron sputtering technology, characterized in that: The application adopts the silicon-carbon negative electrode pre-lithiation method according to any one of claims 1 to 5, and the application is used to prepare a lithium-ion battery, and the lithium battery includes a liquid lithium-ion battery and an all-solid-state lithium-ion battery; The positive electrode material of the lithium battery includes: lithium cobalt oxide, lithium nickel manganese cobalt oxide, lithium nickel aluminum cobalt oxide or lithium-rich manganese-based material.

7. The use of a silicon-carbon negative electrode pre-lithiation method using magnetron sputtering technology according to claim 6, characterized in that: The preparation process of the positive electrode comprises the following steps: stirring and dispersing the positive electrode material, Super-P conductive agent and polyvinylidene fluoride in a solvent at a mass ratio of 85-95:3-8:3-8 to form a positive electrode slurry with a viscosity of 1 Pa·s to 10 Pa·s, scraping the positive electrode slurry onto the surface of an aluminum foil substrate, and rolling it after drying to prepare a positive electrode sheet. The surface loading of the positive electrode sheet is 1 mAh / cm 2 ~5mAh / cm 2 .

8. The use of a silicon-carbon negative electrode pre-lithiation method using magnetron sputtering technology according to claim 6, characterized in that: In the electrolyte of the liquid lithium-ion battery, the lithium salt includes one or more of lithium bis(trifluoromethylsulfonyl)amide, lithium bis(fluorosulfonyl)imide, and lithium hexafluorophosphate; the solvent includes a mixed solution of dimethyl carbonate, diethyl carbonate, and ethyl methyl carbonate; the additive includes fluoroethylene carbonate, and the lithium salt concentration of the electrolyte is 1 to 4 mol / L.

9. The use of a silicon-carbon negative electrode pre-lithiation method using magnetron sputtering technology according to claim 6, characterized in that: The solid electrolyte of the all-solid-state lithium-ion battery includes: sulfide solid electrolyte, halide solid electrolyte; the sulfide solid electrolyte includes: Li2S-P2S5, Li 10 GeP2S 12 、Li7P3S 11 , Li2S-Sb2S3; the halide solid electrolyte includes: Li3MX6 (M=Y, Er, Sc, In, X=F, Cl, Br), Li2MCl6 (M=Zr, Cd, Ti); the preparation method of the solid electrolyte is a 200-400MPa static pressure method.

10. The use of the method for pre-lithiation of a silicon-carbon negative electrode using magnetron sputtering technology according to claim 9, characterized in that: The positive electrode preparation process of the lithium battery comprises the following steps: The positive electrode material, the sulfide solid electrolyte and the conductive agent are uniformly dispersed in a mass ratio of 60 to 80:30 to 10:10, spread on the solid electrolyte, and prepared by a 200 to 400 MPa static pressure method.

Images