Aluminum alloy-artificial SEI dual-protected metal lithium negative electrode and preparation method thereof
By spraying metal powder on the surface of the metal lithium negative electrode of the lithium metal battery and rolling it, and forming an aluminum alloy-artificial SEI dual protective layer with electrochemical deposition technology, the problems of lithium dendrites growth and volume expansion effects are solved, and the cycle life and safety performance of the battery are significantly improved.
Patent Information
- Application Number
- CN202411905552.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-23
- Publication Date
- 2025-04-01
AI Technical Summary
The practical application of lithium metal batteries is hindered by the growth of lithium dendrites, resulting in poor circulation performance and safety hazards, and the volume expansion effect of metal lithium negative electrodes hinders its commercial application.
The preparation method of metal lithium negative electrode with aluminum alloy-artificial SEI dual protection is adopted. By spraying metal powder on the surface of lithium metal and rolling, combined with electrochemical deposition technology, the lithium alloy layer and fluorine-containing lithium salt double protection layer are grown in situ on the surface of lithium metal.
It significantly improves the cycle life of metal lithium negative electrode, improves lithium dendrites, improves battery safety performance, and reduces the sensitivity of lithium metal in the air.
Smart Images
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Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of negative electrode material preparation, and in particular to an aluminum alloy-artificial SEI dual-protected metal lithium negative electrode and a preparation method thereof. Background Art
[0002] Modern society is highly dependent on high-performance electrochemical energy storage systems in the fields of portable electronic devices, renewable energy storage, and electrified transportation. Lithium metal is considered to be an ideal battery anode material due to its ultra-high theoretical specific capacity (3860mAh / g), light weight (6.94g / mol), and lowest redox potential (-3.04V relative to standard hydrogen electrode). However, the practical application of lithium metal batteries (LMBs) is severely hindered by the growth of lithium dendrites, which not only leads to poor cycle performance but also poses safety hazards. The first is the reaction between lithium metal and the electrolyte. Lithium metal has ultra-high chemical reactivity and thermodynamic instability, and produces a passivation SEI layer through spontaneous irreversible reactions with the electrolyte. However, the electrolyte-derived SEI is inhomogeneous and fragile, leading to uneven ion diffusion and growth of lithium dendrites; the second is the inhomogeneity and fragility of the SEI layer. During the cycle, the volume change of lithium metal anodes (LMAs) leads to the growth of dendrites, which can cause continuous fracture / reconstruction of SEI, increase the interfacial lithium ion diffusion resistance and higher voltage polarization; the third is the generation of dead lithium and reduced Coulombic efficiency. Due to the preferential dissolution of the dendrite base and the possible separation of lithium dendrites from the current collector, the generation of residual inactive Li ("dead Li") significantly reduces the Coulombic efficiency (CE), resulting in unsatisfactory cycling performance and ultimately battery failure. Therefore, a stable interface between lithium metal and electrolyte is considered to be the main prerequisite for the operation of lithium metal batteries. Researchers are exploring different methods to build a more stable and uniform SEI layer to improve the performance and safety of lithium metal batteries.
[0003] In recent years, people have modified the series of problems of metal lithium negative electrode from many aspects, including: regulating electrolyte additives, using solid electrolyte membranes, modifying current collectors, and coating protective films on the surface of metal lithium. However, a single modification method is obviously unable to fundamentally solve the problems faced by lithium negative electrodes. It is necessary to combine solid-liquid, solid-solid interfaces, lithium deposition and lithium nucleation, in-situ SEI film growth and other aspects to effectively use different means to modify the lithium negative electrode. Although various methods have achieved certain results, their cycle life and safety are still major problems that need to be solved urgently. During the charging and discharging process, the metal lithium negative electrode reacts with the electrolyte to generate "dead lithium", which destroys its cycle stability; at the same time, the uneven deposition of lithium ions during the charging and discharging process leads to the formation of lithium dendrites, which will pierce the diaphragm in severe cases, causing direct contact between the positive and negative electrodes, forming a short circuit, thereby causing thermal runaway and causing safety accidents; in addition, the volume expansion effect of the metal lithium negative electrode is also a key factor hindering its commercial application. In previous research work, a lot of research has been done on this series of problems, but fundamentally, this series of problems has not been well solved, mainly focusing on the problem of lithium dendrites and the volume expansion effect caused by dead lithium. Summary of the invention
[0004] In order to solve the above technical problems, the purpose of the present invention is to provide an aluminum alloy-artificial SEI dual-protected metal lithium negative electrode and a preparation method thereof. The obtained metal lithium negative electrode has a high cycle life and has been significantly improved in the lithium dendrite problem, greatly improving the safety performance of the battery.
[0005] The technical solution of the present invention to solve the above technical problems is as follows: a method for preparing a metal lithium negative electrode with dual protection of aluminum alloy and artificial SEI is provided, comprising the following steps:
[0006] (1) In an inert atmosphere, spraying metal powder on the surface of lithium metal, rolling, and cutting into discs to obtain composite lithium metal discs;
[0007] (2) Using the composite lithium metal disc obtained in step (1) as the cathode and the pure lithium disc as the anode, assembling a button battery, performing a discharge cycle, in situ growing a lithium alloy layer and a fluorine-containing lithium salt double protective layer on the lithium metal surface by electrochemical deposition, disassembling the button battery, cleaning, and obtaining an aluminum alloy-artificial SEI double-protected metal lithium negative electrode.
[0008] Furthermore, in step (1), the spraying amount of the metal powder is 0.1-10 wt % of the total mass of the lithium metal.
[0009] Furthermore, in step (1), the metal powder is at least one of silver, aluminum, zinc, calcium, magnesium, gallium, nickel, indium and tin.
[0010] Furthermore, in step (1), during rolling, multiple cold rolling processes are performed, with a total pressing amount of 20 μm.
[0011] Furthermore, in step (1), the lithium metal has a thickness of 100-200 μm and is cut into discs with a diameter of 10-15 mm.
[0012] Furthermore, in step (2), the button battery is a CR2032 button battery, the separator is Celgard 2500, the electrolyte is a mixed solution of lithium hexafluorophosphate dissolved in ethylene carbonate, ethyl methyl carbonate and dimethyl carbonate in a volume ratio of 1:1:1, the concentration is 1 mol / L, and the electrolyte additive is 10% fluoroethylene carbonate.
[0013] Further, in step (2), during electrochemical deposition, the current density is 0.06 mA / cm 2 , discharge cycle 12h.
[0014] Furthermore, in step (2), dimethyl carbonate is used to clean the composite lithium metal disc for 10 minutes.
[0015] The present invention also provides an aluminum alloy-artificial SEI dual-protected lithium metal negative electrode prepared by the preparation method of the aluminum alloy-artificial SEI dual-protected lithium metal negative electrode.
[0016] The present invention has the following beneficial effects:
[0017] 1. The present invention increases the specific surface area of the metal lithium negative electrode material by doping with metal particles, reduces the local current density, and causes the lithium ions to be uniformly deposited. At the same time, the contact area between the metal lithium negative electrode and the electrolyte is increased, providing more active sites for lithium ion deposition and promoting the uniform distribution of surface charges, thereby fundamentally inhibiting the growth of lithium dendrites. In addition, the use of electrochemical deposition to introduce a lithium alloy layer and a fluorine-containing lithium salt double protective layer can effectively overcome the defects of the metal lithium negative electrode interface being unstable and prone to dendrites, and the battery assembled with the prepared composite negative electrode material has achieved significantly improved cycle life and greatly improved safety performance.
[0018] 2. The present invention utilizes a combination of a spraying process and a rolling process to directly embed metal particles on the surface of lithium metal, thereby increasing the specific surface area of the metal lithium negative electrode material, reducing the local current density, and allowing lithium ions to be deposited evenly; and the alloy protective layer formed on the surface of lithium metal through an electrochemical reaction has a high potential, a high lithium ion diffusion coefficient, and high wettability to solid electrolytes, which is beneficial to improving interface stability; at the same time, the protective layer of fluorine-containing lithium salt, as part of the solid electrolyte interface (SEI) film, can reduce side reactions between the electrolyte and the electrode, effectively inhibit the growth of lithium dendrites, and improve the safety performance of the battery.
[0019] 3. The present invention utilizes the insensitivity of some metals to air to improve the stability of lithium metal materials in the air and reduce the sensitivity of lithium metal in the air; the combination of powder rolling process and electrochemical deposition can not only provide reversible capacity for battery cycle, but also the surface alloy phase can be used as a three-dimensional lithium-philic framework to regulate Li + The uniform deposition of lithium ions limits the huge volume changes during the cycle; the fluorine-containing lithium salt acts as a second protective layer to further inhibit the side reactions between the electrolyte and lithium metal, reduce the generation of inactive lithium, and inhibit the uneven deposition of lithium dendrites; the low-cost rolling process and electrochemical deposition overcome the high cost and high safety hazards of using the method of melting lithium to achieve changes in the structure of metallic lithium. BRIEF DESCRIPTION OF THE DRAWINGS
[0020] Figure 1 This is a SEM image of the surface of the metal lithium negative electrode after rolling in Example 6;
[0021] Figure 2 This is the cycle diagram of the symmetrical battery with aluminum alloy-artificial SEI dual protection of lithium metal negative electrode obtained in Example 6;
[0022] Figure 3 This is a comparison chart of the full battery cycle performance of the aluminum alloy-artificial SEI dual-protected metal lithium negative electrode and the pure metal lithium negative electrode obtained in Example 6. DETAILED DESCRIPTION
[0023] The principles and features of the present invention are described below, and the examples are only used to explain the present invention and are not used to limit the scope of the present invention. If no specific conditions are specified in the embodiments, they are carried out according to normal conditions or conditions recommended by the manufacturer. If the manufacturer of the reagents or instruments is not specified, they are all conventional products that can be purchased commercially.
[0024] Example 1
[0025] A metal lithium negative electrode with aluminum alloy-artificial SEI dual protection, the preparation method of which comprises the following steps:
[0026] (1) In an argon atmosphere, aluminum powder (1 wt%) was sprayed on a 100 μm thick lithium metal surface, cold rolled, and cut into 14 mm diameter discs to obtain composite lithium metal discs;
[0027] (2) The composite lithium metal disc obtained in step (1) was used as the cathode and the commercial pure lithium disc was used as the anode to assemble a CR2032 button battery. The separator was Celgard 2500. The electrolyte was lithium hexafluorophosphate (1 mol / L) dissolved in a mixed solution of ethylene carbonate, ethyl methyl carbonate and dimethyl carbonate in a volume ratio of 1:1:1, and the electrolyte additive was 10% fluoroethylene carbonate. The current density was 0.06 mA / cm 2, the discharge cycle was 12h, and a double protective layer of lithium alloy layer and fluorine-containing lithium salt was in situ grown on the surface of lithium metal by electrochemical deposition. The button battery was disassembled, and the composite lithium metal disc was cleaned with dimethyl carbonate for 10min to obtain a metal lithium negative electrode with aluminum alloy-artificial SEI double protection.
[0028] Example 2
[0029] A metal lithium negative electrode with aluminum alloy-artificial SEI dual protection, the preparation method of which comprises the following steps:
[0030] (1) In an argon atmosphere, aluminum powder (2 wt%) was sprayed on a 100 μm thick lithium metal surface, cold rolled, and cut into 14 mm diameter discs to obtain composite lithium metal discs;
[0031] (2) The composite lithium metal disc obtained in step (1) was used as the cathode and the commercial pure lithium disc was used as the anode to assemble a CR2032 button battery. The separator was Celgard 2500. The electrolyte was lithium hexafluorophosphate (1 mol / L) dissolved in a mixed solution of ethylene carbonate, ethyl methyl carbonate and dimethyl carbonate in a volume ratio of 1:1:1, and the electrolyte additive was 10% fluoroethylene carbonate. The current density was 0.06 mA / cm 2 , the discharge cycle was 12h, and a double protective layer of lithium alloy layer and fluorine-containing lithium salt was in situ grown on the surface of lithium metal by electrochemical deposition. The button battery was disassembled, and the composite lithium metal disc was cleaned with dimethyl carbonate for 10min to obtain a metal lithium negative electrode with aluminum alloy-artificial SEI double protection.
[0032] Example 3
[0033] A metal lithium negative electrode with aluminum alloy-artificial SEI dual protection, the preparation method of which comprises the following steps:
[0034] (1) In an argon atmosphere, aluminum powder (3 wt%) was sprayed on a 100 μm thick lithium metal surface, cold rolled, and cut into 14 mm diameter discs to obtain composite lithium metal discs;
[0035] (2) The composite lithium metal disc obtained in step (1) was used as the cathode and the commercial pure lithium disc was used as the anode to assemble a CR2032 button battery. The separator was Celgard 2500. The electrolyte was lithium hexafluorophosphate (1 mol / L) dissolved in a mixed solution of ethylene carbonate, ethyl methyl carbonate and dimethyl carbonate in a volume ratio of 1:1:1, and the electrolyte additive was 10% fluoroethylene carbonate. The current density was 0.06 mA / cm 2 , the discharge cycle was 12h, and a double protective layer of lithium alloy layer and fluorine-containing lithium salt was in situ grown on the surface of lithium metal by electrochemical deposition. The button battery was disassembled, and the composite lithium metal disc was cleaned with dimethyl carbonate for 10min to obtain a metal lithium negative electrode with aluminum alloy-artificial SEI double protection.
[0036] Example 4
[0037] A metal lithium negative electrode with aluminum alloy-artificial SEI dual protection, the preparation method of which comprises the following steps:
[0038] (1) In an argon atmosphere, aluminum powder (5 wt%) was sprayed on a 100 μm thick lithium metal surface, cold rolled, and cut into 14 mm diameter discs to obtain composite lithium metal discs;
[0039] (2) The composite lithium metal disc obtained in step (1) was used as the cathode and the commercial pure lithium disc was used as the anode to assemble a CR2032 button battery. The separator was Celgard 2500. The electrolyte was lithium hexafluorophosphate (1 mol / L) dissolved in a mixed solution of ethylene carbonate, ethyl methyl carbonate and dimethyl carbonate in a volume ratio of 1:1:1, and the electrolyte additive was 10% fluoroethylene carbonate. The current density was 0.06 mA / cm 2 , the discharge cycle was 12h, and a double protective layer of lithium alloy layer and fluorine-containing lithium salt was in situ grown on the surface of lithium metal by electrochemical deposition. The button battery was disassembled, and the composite lithium metal disc was cleaned with dimethyl carbonate for 10min to obtain a metal lithium negative electrode with aluminum alloy-artificial SEI double protection.
[0040] Example 5
[0041] A metal lithium negative electrode with aluminum alloy-artificial SEI dual protection, the preparation method of which comprises the following steps:
[0042] (1) In an argon atmosphere, aluminum powder (10 wt%) was sprayed on a 100 μm thick lithium metal surface, cold rolled, and cut into 14 mm diameter discs to obtain composite lithium metal discs;
[0043] (2) The composite lithium metal disc obtained in step (1) was used as the cathode and the commercial pure lithium disc was used as the anode to assemble a CR2032 button battery. The separator was Celgard 2500. The electrolyte was lithium hexafluorophosphate (1 mol / L) dissolved in a mixed solution of ethylene carbonate, ethyl methyl carbonate and dimethyl carbonate in a volume ratio of 1:1:1, and the electrolyte additive was 10% fluoroethylene carbonate. The current density was 0.06 mA / cm 2 , the discharge cycle was 12h, and a double protective layer of lithium alloy layer and fluorine-containing lithium salt was in situ grown on the surface of lithium metal by electrochemical deposition. The button battery was disassembled, and the composite lithium metal disc was cleaned with dimethyl carbonate for 10min to obtain a metal lithium negative electrode with aluminum alloy-artificial SEI double protection.
[0044] Example 6
[0045] A metal lithium negative electrode with aluminum alloy-artificial SEI dual protection, the preparation method of which comprises the following steps:
[0046] (1) In an argon atmosphere, aluminum powder (3 wt%) was sprayed on a 165 μm thick lithium metal surface, cold rolled, and cut into 14 mm diameter discs to obtain composite lithium metal discs;
[0047] (2) The composite lithium metal disc obtained in step (1) was used as the cathode and the commercial pure lithium disc was used as the anode to assemble a CR2032 button battery. The separator was Celgard 2500. The electrolyte was lithium hexafluorophosphate (1 mol / L) dissolved in a mixed solution of ethylene carbonate, ethyl methyl carbonate and dimethyl carbonate in a volume ratio of 1:1:1, and the electrolyte additive was 10% fluoroethylene carbonate. The current density was 0.06 mA / cm 2 , the discharge cycle was 12h, and a double protective layer of lithium alloy layer and fluorine-containing lithium salt was in situ grown on the surface of lithium metal by electrochemical deposition. The button battery was disassembled, and the composite lithium metal disc was cleaned with dimethyl carbonate for 10min to obtain a metal lithium negative electrode with aluminum alloy-artificial SEI double protection.
[0048] Example 7
[0049] A metal lithium negative electrode with aluminum alloy-artificial SEI dual protection, the preparation method of which comprises the following steps:
[0050] (1) In an argon atmosphere, aluminum powder (3 wt%) was sprayed on a 200 μm thick lithium metal surface, cold rolled, and cut into 14 mm diameter discs to obtain composite lithium metal discs;
[0051] (2) The composite lithium metal disc obtained in step (1) was used as the cathode and the commercial pure lithium disc was used as the anode to assemble a CR2032 button battery. The separator was Celgard 2500. The electrolyte was lithium hexafluorophosphate (1 mol / L) dissolved in a mixed solution of ethylene carbonate, ethyl methyl carbonate and dimethyl carbonate in a volume ratio of 1:1:1, and the electrolyte additive was 10% fluoroethylene carbonate. The current density was 0.06 mA / cm 2 , the discharge cycle was 12h, and a double protective layer of lithium alloy layer and fluorine-containing lithium salt was in situ grown on the surface of lithium metal by electrochemical deposition. The button battery was disassembled, and the composite lithium metal disc was cleaned with dimethyl carbonate for 10min to obtain a metal lithium negative electrode with aluminum alloy-artificial SEI double protection.
[0052] Example 8
[0053] A metal lithium negative electrode with aluminum alloy-artificial SEI dual protection, the preparation method of which comprises the following steps:
[0054] (1) In an argon atmosphere, magnesium powder (3 wt%) was sprayed on a 165 μm thick lithium metal surface, cold rolled, and cut into 14 mm diameter discs to obtain composite lithium metal discs;
[0055] (2) The composite lithium metal disc obtained in step (1) was used as the cathode and the commercial pure lithium disc was used as the anode to assemble a CR2032 button battery. The separator was Celgard 2500. The electrolyte was lithium hexafluorophosphate (1 mol / L) dissolved in a mixed solution of ethylene carbonate, ethyl methyl carbonate and dimethyl carbonate in a volume ratio of 1:1:1, and the electrolyte additive was 10% fluoroethylene carbonate. The current density was 0.06 mA / cm 2 , the discharge cycle was 12h, and a double protective layer of lithium alloy layer and fluorine-containing lithium salt was in situ grown on the surface of lithium metal by electrochemical deposition. The button battery was disassembled, and the composite lithium metal disc was cleaned with dimethyl carbonate for 10min to obtain a metal lithium negative electrode with aluminum alloy-artificial SEI double protection.
[0056] Example 9
[0057] A metal lithium negative electrode with aluminum alloy-artificial SEI dual protection, the preparation method of which comprises the following steps:
[0058] (1) In an argon atmosphere, magnesium powder (5 wt%) was sprayed on a 165 μm thick lithium metal surface, cold rolled, and cut into 14 mm diameter discs to obtain composite lithium metal discs;
[0059] (2) The composite lithium metal disc obtained in step (1) was used as the cathode and the commercial pure lithium disc was used as the anode to assemble a CR2032 button battery. The separator was Celgard 2500. The electrolyte was lithium hexafluorophosphate (1 mol / L) dissolved in a mixed solution of ethylene carbonate, ethyl methyl carbonate and dimethyl carbonate in a volume ratio of 1:1:1, and the electrolyte additive was 10% fluoroethylene carbonate. The current density was 0.06 mA / cm 2 , the discharge cycle was 12h, and a double protective layer of lithium alloy layer and fluorine-containing lithium salt was in situ grown on the surface of lithium metal by electrochemical deposition. The button battery was disassembled, and the composite lithium metal disc was cleaned with dimethyl carbonate for 10min to obtain a metal lithium negative electrode with aluminum alloy-artificial SEI double protection.
[0060] Test example
[0061] The SEM image of the surface of the metal lithium negative electrode after rolling in Example 6 is obtained. Figure 1 As shown; the symmetrical battery was assembled and tested, and the results are as follows Figure 2 shown.
[0062] The aluminum alloy-artificial SEI dual-protected metal lithium negative electrode and the pure metal lithium negative electrode obtained in Example 6 were matched with the NCM811 positive electrode to assemble a full battery test: Celgard 2500 was selected as the separator, and the electrolyte was 1 mol / L lithium hexafluorophosphate dissolved in a mixed solution of ethylene carbonate (EC), ethyl methyl carbonate (EMC) and dimethyl carbonate (DMC) in a volume ratio of 1:1:1, and 10% fluoroethylene carbonate (FEC) was used as an electrolyte additive; the electrochemical performance test results are as follows: Figure 3 shown.
[0063] Depend on Figure 1 It can be seen that through rolling, aluminum particles were successfully embedded on the surface of lithium metal, providing active sites for the growth of alloy layer and the in situ electrochemical deposition of fluorine-containing lithium salt protective layer.
[0064] Depend on Figure 2 It can be seen that at a current density of 0.5 mA / cm 2 , surface capacity is 0.5mAh / cm 2 Under the conditions, the symmetrical battery assembled with the metal lithium negative electrode obtained in Example 6 exhibits a cycle life of more than 500 hours. This is because the double protective layer of the alloy layer and the fluorine-containing lithium salt helps the metal lithium negative electrode to achieve more uniform lithium deposition / stripping behavior, effectively inhibits the growth of lithium dendrites, and reduces the short circuit inside the battery.
[0065] Depend on Figure 3 It can be seen that compared with pure lithium materials, the full battery assembled with the metal lithium negative electrode obtained in Example 6 based on the NCM811 positive electrode material has excellent cycle stability, and can stably cycle for more than 200 cycles under 0.5C rate conditions, and the capacity retention rate reaches 84.2%.
[0066] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.
Claims
1. A method for preparing a metallic lithium negative electrode with dual protection of aluminum alloy and artificial SEI, characterized in that: The following steps are involved: (1) In an inert atmosphere, spraying metal powder on the surface of lithium metal, rolling, and cutting into discs to obtain composite lithium metal discs; (2) Using the composite lithium metal disc obtained in step (1) as the cathode and the pure lithium disc as the anode, assembling a button battery, performing a discharge cycle, in situ growing a lithium alloy layer and a fluorine-containing lithium salt double protective layer on the lithium metal surface by electrochemical deposition, disassembling the button battery, cleaning, and obtaining an aluminum alloy-artificial SEI double-protected metal lithium negative electrode.
2. The method for preparing the aluminum alloy-artificial SEI dual-protected metal lithium negative electrode according to claim 1, characterized in that: In step (1), the spraying amount of the metal powder is 0.1-10 wt % of the total mass of the lithium metal.
3. The method for preparing the aluminum alloy-artificial SEI dual-protected metal lithium negative electrode according to claim 1, characterized in that: In step (1), the metal powder is at least one of silver, aluminum, zinc, calcium, magnesium, gallium, nickel, indium and tin.
4. The method for preparing the aluminum alloy-artificial SEI dual-protected metal lithium negative electrode according to claim 1, characterized in that: In step (1), during rolling, multiple cold rolling processes are adopted, and the total pressing amount is 20 μm.
5. The method for preparing the aluminum alloy-artificial SEI dual-protected metal lithium negative electrode according to claim 1, characterized in that: In step (1), the lithium metal has a thickness of 100-200 μm and is cut into discs with a diameter of 10-15 mm.
6. The method for preparing the aluminum alloy-artificial SEI dual-protected metal lithium negative electrode according to claim 1, characterized in that: In step (2), the button cell is a CR2032 button cell, the separator is Celgard 2500, the electrolyte is a mixed solution of lithium hexafluorophosphate dissolved in ethylene carbonate, ethyl methyl carbonate and dimethyl carbonate in a volume ratio of 1:1:1, the concentration is 1 mol / L, and the electrolyte additive is 10% fluoroethylene carbonate.
7. The method for preparing the aluminum alloy-artificial SEI dual-protected metal lithium negative electrode according to claim 1, characterized in that: In step (2), during electrochemical deposition, the current density is 0.06 mA / cm 2 , discharge cycle 12h.
8. The method for preparing the aluminum alloy-artificial SEI dual-protected metal lithium negative electrode according to claim 1, characterized in that: In step (2), dimethyl carbonate is used to clean the composite lithium metal disc for 10 minutes.
9. Aluminum alloy-artificial SEI dual-protected lithium metal negative electrode obtained by the method for preparing an aluminum alloy-artificial SEI dual-protected lithium metal negative electrode according to any one of claims 1 to 8.