Graphite electrode preparation method for improving fast charge through regulation and control of pre-lithiation and interface nitridation
By generating a Li3N/LixNy composite interface layer on the surface of a graphite electrode, the problems of uneven pre-lithiation and unstable modification of existing graphite anode electrodes are solved, realizing the preparation of graphite electrodes with high efficiency, fast charging and long cycle life, which is suitable for lithium-ion battery anode materials.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-12-30
- Publication Date
- 2026-04-10
AI Technical Summary
Existing pre-lithiation methods for graphite anode electrodes suffer from operational hazards, uneven dispersion, low control precision, high cost, cumbersome processes, and cycling expansion and initial efficiency reduction caused by modification methods, making it difficult to achieve efficient fast charging and long cycle life.
Pre-lithiation is carried out through pressure contact reaction with the aid of a medium to form a highly reactive lithium surface, and a Li3N/LixNy composite interface layer is generated in situ on the graphite electrode surface. Combined with drying treatment, a stable interface structure is formed, realizing rapid and uniform lithium ion insertion and high ionic conductivity.
It achieves a 10-20% improvement in the initial coulombic efficiency of graphite anodes, significantly enhances fast-charging performance, maintains a capacity retention rate of ≥90% after 500 cycles, has a simple process that is easy to industrialize, and combines high initial efficiency with excellent fast-charging performance.
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Abstract
Description
Technical Field
[0001] This invention relates to the field of battery manufacturing, and in particular to a method for preparing graphite electrodes that improves fast charging through pre-lithiation and interface nitridation regulation. Background Technology
[0002] Existing pre-lithiation methods for graphite anode electrodes mainly include lithium powder pre-lithiation, short-circuit pre-lithiation with lithium metal, and chemical pre-lithiation. Lithium powder pre-lithiation involves directly mixing active lithium powder into the electrode, compensating for lithium loss through a solid-phase reaction; however, lithium powder is highly environmentally sensitive, the operation is hazardous, and controlling dispersion uniformity is difficult. Short-circuit pre-lithiation involves short-circuiting the anode with an external lithium source, relying on the potential difference to drive lithium migration; however, the process control precision is low, consistency is poor, and an additional lithium source separation step is required, making the process cumbersome. Chemical pre-lithiation utilizes a reducing lithium compound solution to react with the anode via a redox reaction for lithium replenishment; however, the reagents are expensive, it is environmentally sensitive, and residues may degrade electrode performance.
[0003] Current modification methods for fast-charging graphite mainly include surface amorphous carbon coating, gradient doping with boron / nitrogen, and microcrystalline secondary granulation. Surface amorphous carbon coating involves depositing a layer of porous amorphous carbon on the graphite surface, forming a fast ion channel that allows lithium ions to bypass solvent co-intercalation and directly intercalate into the interior; however, uneven coating thickness can leave exposed crystal faces, still triggering solvent co-intercalation, leading to cycle expansion and a decrease in initial efficiency. Gradient doping involves gradient doping of non-metals such as boron / nitrogen onto the surface of graphite particles to improve interlayer conductivity and lithium-ion diffusion coefficient, achieving fast charging; however, controlling the doping concentration gradient is complex, and doped atoms tend to migrate and aggregate at high temperatures, resulting in a decrease in diffusion coefficient. Microcrystalline graphite secondary granulation involves mixing micron-sized natural graphite with nanocrystals and then granulating them, utilizing grain boundary defects to store lithium ions, shortening the diffusion path, and buffering volume expansion; however, excessive grain boundaries can exacerbate side reactions, resulting in low initial coulombic efficiency, and the particle size distribution is difficult to control precisely. Summary of the Invention
[0004] Objective: To address the shortcomings of existing technologies, this invention provides a method for preparing graphite electrodes that enhances fast charging through pre-lithiation and interface nitridation. With the assistance of a dielectric, rapid and uniform pre-lithiation of the graphite bulk phase is achieved under mild conditions via pressure contact reaction, solving the problems of low initial coulombic efficiency, slow fast-charging kinetics, and poor rate performance of graphite anodes. This method achieves a 10-20% improvement in initial coulombic efficiency of the graphite anode, significantly enhanced fast-charging performance, and enables high-rate charge / discharge and long cycle life.
[0005] Technical Solution: To achieve the above technical objectives, this invention provides a method for preparing a graphite electrode that enhances fast charging through pre-lithiation and interface nitridation, comprising the following steps:
[0006] S1: The graphite electrode and the lithium source are brought into pressure contact with each other in a carbonyl aromatic hydrocarbon medium to form a pre-lithiated graphite electrode with highly reactive lithium on the surface.
[0007] S2: Immediately immerse the pre-lithiated graphite electrode in a nitrogen-containing precursor solution to generate Li3N / Li in situ on the graphite electrode surface. x N y Composite interface layer, Li3N / Li x N y The composite interface layer and the graphite substrate are covalently bonded by CN-Li to form a stable interface structure SEI;
[0008] S3: Dry the graphite electrode under an argon or nitrogen atmosphere to completely remove residual solvent and obtain a structurally stable lithium nitride-rich graphite composite electrode.
[0009] Furthermore, the graphite electrode has a concentration of 2 mg / cm³. 2 The lithium source is artificial graphite, natural graphite, mesophase carbon microspheres, soft carbon, or hard carbon; the lithium source is a smooth-surfaced metallic lithium foil, lithium strip, or lithium film deposited on a carrier.
[0010] Furthermore, the carbonyl aromatic hydrocarbon medium is an ether reagent of carbonyl aromatic hydrocarbon, with a concentration of 0.01 mol / L to 1 mol / L. When the carbonyl aromatic hydrocarbon medium comes into contact with the lithium source, it can rapidly form a highly active and migratory lithium-aromatic hydrocarbon complex. The lithium-aromatic hydrocarbon complex acts as a charge carrier, enabling rapid and spatially uniform bulk pre-intercalation of lithium ions from the lithium source into the interior of the graphite electrode, forming a pre-lithiated graphite electrode with a highly reactive lithium surface.
[0011] Furthermore, the carbonyl aromatic hydrocarbon molecules constituting the carbonyl aromatic hydrocarbon medium include one or more combinations of benzophenone, tetrahydronaphthone, anthrone, phenanthrone, 9-fluorenone, acetophenone, and naphthyl acetophenone, and the ether solvent is selected from one or more combinations of dimethoxyethane, tetrahydrofuran, 2-methyltetrahydrofuran, tetrahydropyran, and 1,3-dioxolane.
[0012] Furthermore, the pre-lithiation degree of the pre-lithiated graphite electrode is achieved by controlling the contact time between the graphite electrode and the lithium source, the applied pressure, and the medium concentration to achieve an initial coulombic efficiency of 90%-120%; wherein the contact time is 1min-30min and the applied pressure is 0.1kg-1kg.
[0013] Furthermore, the nitrogen-containing precursor solution is at least one of the following: a functionalized ionic liquid containing cyano, amino, or azide groups, a nitrogen-doped carbon precursor, or a polydentate nitrogen ligand solution with coordination ability: including one or more of tetramethylethylenediamine, ammonium hexafluorozirconate, N,N-dimethylethylenediamine, diphenyl azidophosphate, ammonium hexafluorotitanate, ethylenediaminetetraacetic acid, and melamine.
[0014] Furthermore, the pre-lithiated graphite electrode is immersed in a nitrogen-containing precursor solution and subjected to interfacial chemical reaction at 20-50℃. The concentration of the nitrogen-containing precursor solution is 0.05mol / L~2mol / L, and the reaction time is 1min~30min.
[0015] Furthermore, the inert atmosphere is argon or nitrogen; the drying temperature is 60-120℃, and the drying time is 2-12 hours, to ensure that the residual solvent in the electrode is fully removed without affecting the electrode structure and performance.
[0016] A pre-lithiated graphite electrode with interfacial nitridation obtained by a preparation method is used as a negative electrode material.
[0017] A lithium-ion battery is manufactured using a pre-lithiated graphite electrode with interface nitridation as the negative electrode material. The initial coulombic efficiency of the composite electrode is ≥95%, and the capacity retention rate is ≥90% after 500 cycles at 1C rate.
[0018] Beneficial effects:
[0019] 1. Using carbonyl aromatic hydrocarbon-ether medium pressure contact pre-lithiation, lithium ions can be rapidly and uniformly embedded in the bulk phase without high temperature or inert atmosphere. By simply adjusting the contact time, pressure and medium concentration, the degree of pre-lithiation can be precisely controlled, solving the problems of uneven dispersion, powder shedding and environmental sensitivity of traditional lithium powder. The process can be directly integrated into existing coating production lines.
[0020] 2. Constructing Li3N / Li through in-situ liquid-phase nitrogen x N y The composite interface layer has high interfacial ionic conductivity, which significantly reduces fast-charging polarization and maintains ≥90% capacity after 500 cycles. It overcomes the technical defects of unstable interface and easy side reaction in conventional surface coating or doping modification.
[0021] 3. All processes of this invention are completed in a low-temperature (20-50℃) liquid phase environment, without the need for high-temperature sintering or complex vacuum equipment. The reaction conditions are mild, the steps are simple, and they are compatible with existing electrode preparation processes, making it easy to integrate and scale up on conventional battery production lines. This overcomes the industrialization bottlenecks of complex processes, high costs, and difficulty in scaling up processes such as gradient doping and high-temperature nitriding.
[0022] 4. The lithium nitride-rich graphite composite electrode prepared by this invention possesses both high initial efficiency (≥95%) and excellent fast-charging performance. Its unique nitrogen-rich interface structure provides an ultra-fast diffusion channel for lithium ions, significantly improving the electrode's high-rate charging capability and achieving synergistic enhancement of "lithium replenishment" and "fast charging" functions. This provides an efficient negative electrode material solution for developing high-energy-density, long-life fast-charging lithium-ion batteries. Attached Figure Description
[0023] Figure 1 Figure 1 shows the morphology of the graphite electrodes of Example 1 and Comparative Example 2 of the present invention; Figure (a) shows the morphology of the interface nitrided pre-lithiated graphite electrode of Example 1, and Figure (b) shows the morphology of the pre-lithiated graphite electrode of Comparative Example 2.
[0024] Figure 2 Figure 1 shows the microstructure of the graphite electrodes of Example 1 and Comparative Example 3 of the present invention; Figure (a) shows the microstructure of the pre-lithiated graphite electrode with interface nitridation of Example 1, and Figure (b) shows the microstructure of the graphite electrode of Comparative Example 3 with conventional electrolyte as the medium.
[0025] Figure 3 XPS spectra of the pre-lithiated graphite electrode prepared by interface nitriding in Example 1 and the original graphite electrode of Comparative Example 1 are shown in the figures. In the figures, the intensity on the horizontal axis represents the strength of the detected photoelectron signal; the binding energy represents the energy required for the transition of inner-shell electrons. In the figures, a represents the XPS spectra of the graphite electrode surfaces of Example 1 and Comparative Example 1 at C 1s, b represents the XPS spectra of the graphite electrode surfaces of Example 1 and Comparative Example 1 at Li 1s, and c represents the XPS spectra of the graphite electrode surfaces of Example 1 and Comparative Example 1 at N 1s.
[0026] Figure 4 The figure shows the cyclic voltammetry test results of the interface-nitrided pre-lithiated graphite electrode of Example 1 of the present invention; in the figure, the horizontal axis represents the voltage, which is the working voltage of the voltage platform; the vertical axis represents the current response intensity of the redox reaction at the corresponding voltage.
[0027] Figure 5 The results of the first charge-discharge test of the interface-nitrided pre-lithiated graphite electrode of Example 1 and the original graphite electrode of Comparative Example 1 are shown. The horizontal axis represents the capacity, which indicates the specific capacity of the battery charge-discharge; the vertical axis represents the voltage, which indicates the operating voltage of the voltage plateau.
[0028] Figure 6 The figures show the rate performance test results of the interface nitrided pre-lithiated graphite electrode of Example 1 and the dielectric-only pre-lithiated graphite electrode of Comparative Example 2. In the figures, the horizontal axis Cycle number represents the number of cycles in the charge-discharge test; the vertical axis Specific capacity represents the amount of electricity that can be stored per unit mass of electrode material.
[0029] Figure 7The figures show the cycle performance test results of the interface-nitrided pre-lithiated graphite electrode of Example 1 and the original graphite electrode of Comparative Example 1. In the figure, the Cycle number on the horizontal axis represents the number of cycles in the charge-discharge test; the Specific capacity on the vertical axis 1 represents the specific capacity, which represents the amount of electricity that can be stored per unit mass of electrode material; and the Initial Coulomb Efficiency (ICE) on the vertical axis 2 represents the ratio of the initial charge capacity to the initial discharge capacity.
[0030] Figure 8 This is a schematic diagram comparing the pre-lithiation efficiency of Example 2 and Comparative Example 3 of the present invention. Detailed Implementation
[0031] The technical solutions in the embodiments of the present invention will be clearly and completely described below.
[0032] Example 1: A method for preparing a graphite electrode to improve fast charging through pre-lithiation and interface nitridation, comprising the following steps:
[0033] Step 1, Preparation of pre-lithiated graphite electrode: Prepare a 0.1 mol / L medium, dissolve 0.182 g of benzophenone in 10 ml of dimethoxyethane by stirring thoroughly, use lithium foil as the lithium source to contact the graphite electrode, and contact for 20 min under a pressure of 0.1 kg to obtain a pre-lithiated graphite electrode with an initial coulombic efficiency of about 110%.
[0034] Step 2, prepare the nitride-interface pre-lithiated graphite electrode, such as... Figure 1 As shown in Figure a: The pre-lithiated graphite electrode from step 1 was immediately immersed in 10 ml of a 0.1 mol / L tetramethylethylenediamine solution, and an interfacial chemical reaction was carried out at 20 °C for 15 min, resulting in the in-situ formation of Li3N / Li on the graphite electrode surface. x N y Composite interface layers, such as morphology Figure 1 As shown in Figure a, the microstructure is as follows Figure 2 As shown in Figure a, the XPS spectrum of the pre-lithiated graphite electrode is as follows: Figure 3 As shown;
[0035] Step 3, Electrode Drying Treatment: The pre-lithiated graphite electrode with nitride interface from Step 2 was dried at 80°C for 2 hours under an argon atmosphere to completely remove residual solvent, obtaining a structurally stable lithium nitride-rich graphite composite electrode. The cyclic voltammetry test results are as follows: Figure 4 As shown.
[0036] Example 2: A method for preparing a graphite electrode to improve fast charging through pre-lithiation and interface nitridation, comprising the following steps:
[0037] Step 1, Preparation of pre-lithiated graphite electrode: Prepare a 0.1 mol / L medium, dissolve 0.146 g of tetrahydronaphthone in 10 ml of dimethoxyethane by stirring thoroughly, use lithium foil as the lithium source to contact the graphite electrode, and contact for 20 min under a pressure of 0.2 kg to obtain a pre-lithiated graphite electrode with an initial coulombic efficiency of about 110%.
[0038] Step 2, Preparation of nitrided interfacial pre-lithiated graphite electrode: The pre-lithiated graphite electrode from Step 1 is immediately immersed in 10 ml of a 0.1 mol / L tetramethylethylenediamine solution, and an interfacial chemical reaction is carried out at 25 °C for 15 min, resulting in the in-situ generation of Li3N / Li on the graphite electrode surface. x N y Composite interface layer, morphology as Figure 1 As shown in b;
[0039] Step 3, electrode drying treatment: The pre-lithiated graphite electrode with nitride interface from step 2 is dried at 80°C for 2 hours under an argon atmosphere to completely remove residual solvent and obtain a structurally stable lithium nitride-rich graphite composite electrode.
[0040] Example 3: A method for preparing a graphite electrode to improve fast charging through pre-lithiation and interface nitridation, comprising the following steps:
[0041] Step 1, Preparation of pre-lithiated graphite electrode: Prepare a 0.5 mol / L medium, dissolve 0.901 g of 9-fluorenone in 10 ml of tetrahydrofuran by stirring thoroughly, use lithium foil as the lithium source to contact the graphite electrode, and contact for 15 min under a pressure of 0.1 kg to obtain a pre-lithiated graphite electrode with an initial coulombic efficiency of about 110%.
[0042] Step 2, Preparation of nitrided interfacial pre-lithiated graphite electrode: The pre-lithiated graphite electrode from Step 1 is immediately immersed in 10 ml of 0.2 mol / L ethylenediaminetetraacetic acid solution, and an interfacial chemical reaction is carried out at 35°C for 6 min, resulting in the in-situ generation of Li3N / Li on the graphite electrode surface. x N y Composite interface layer, microstructure such as Figure 2 As shown in b;
[0043] Step 3, electrode drying treatment: The pre-lithiated graphite electrode with nitride interface from step 2 is dried at 80°C for 2 hours under an argon atmosphere to completely remove residual solvent and obtain a structurally stable lithium nitride-rich graphite composite electrode.
[0044] Example 4: A method for preparing a graphite electrode to improve fast charging through pre-lithiation and interface nitridation, comprising the following steps:
[0045] Step 1, Preparation of pre-lithiated graphite electrode: Prepare a 0.5 mol / L medium, dissolve 0.971 g of anthrone in 10 ml of 2-methyltetrahydrofuran by stirring thoroughly, use lithium foil as the lithium source to contact the graphite electrode, and contact for 15 min under a pressure of 0.1 kg to obtain a pre-lithiated graphite electrode with an initial coulombic efficiency of about 110%.
[0046] Step 2, Preparation of nitrided interfacial pre-lithiated graphite electrode: The pre-lithiated graphite electrode from Step 1 is immediately immersed in 10 ml of 0.1 mol / L ethylenediaminetetraacetic acid solution, and an interfacial chemical reaction is carried out at 25 °C for 9 min, resulting in the in-situ generation of Li3N / Li on the graphite electrode surface. x N y Composite interface layer;
[0047] Step 3, electrode drying treatment: The pre-lithiated graphite electrode with nitride interface from step 2 is dried at 80°C for 2 hours under an argon atmosphere to completely remove residual solvent and obtain a structurally stable lithium nitride-rich graphite composite electrode.
[0048] Example 5: A method for preparing a graphite electrode to improve fast charging through pre-lithiation and interface nitridation, comprising the following steps:
[0049] Step 1, Preparation of pre-lithiated graphite electrode: Prepare a 0.5 mol / L medium, dissolve 0.911 g of benzophenone in 10 ml of 1,3-dioxolane by stirring thoroughly, use lithium foil as the lithium source to contact the graphite electrode, and contact for 12 min under a pressure of 0.1 kg to obtain a pre-lithiated graphite electrode with an initial coulombic efficiency of about 110%.
[0050] Step 2, Preparation of nitrided interfacial pre-lithiated graphite electrode: The pre-lithiated graphite electrode from Step 1 is immediately immersed in 10 ml of a 0.1 mol / L ammonium hexafluorozirconate solution, and an interfacial chemical reaction is carried out at 25 °C for 8 min, resulting in the in-situ generation of Li3N / Li on the graphite electrode surface. x N y Composite interface layer;
[0051] Step 3, electrode drying treatment: The pre-lithiated graphite electrode with nitride interface from step 2 is dried at 80°C for 2 hours under an argon atmosphere to completely remove residual solvent and obtain a structurally stable lithium nitride-rich graphite composite electrode.
[0052] Example 6: A method for preparing a graphite electrode to improve fast charging through pre-lithiation and interface nitridation, comprising the following steps:
[0053] Step 1, Preparation of pre-lithiated graphite electrode: Prepare a 0.1 mol / L medium, dissolve 0.162 g of phenacetin in 10 ml of tetrahydropyran by stirring thoroughly, use lithium foil as the lithium source to contact the graphite electrode, and contact for 15 min under a pressure of 0.2 kg to obtain a pre-lithiated graphite electrode with an initial coulombic efficiency of about 110%.
[0054] Step 2, Preparation of nitrided interfacial pre-lithiated graphite electrode: The pre-lithiated graphite electrode from Step 1 is immediately immersed in 10 ml of 0.1 mol / L ammonium hexafluorozirconate solution, and an interfacial chemical reaction is carried out at 25 °C for 10 min, resulting in the in-situ generation of Li3N / Li on the graphite electrode surface. x N y Composite interface layer;
[0055] Step 3, electrode drying treatment: The pre-lithiated graphite electrode with nitride interface from step 2 is dried at 80°C for 2 hours under an argon atmosphere to completely remove residual solvent and obtain a structurally stable lithium nitride-rich graphite composite electrode.
[0056] Example 7: A method for preparing a graphite electrode to improve fast charging through pre-lithiation and interface nitridation, comprising the following steps:
[0057] Step 1, Preparation of pre-lithiated graphite electrode: Prepare a 1 mol / L medium, dissolve 1.802 g of 9-fluorenone in 10 ml of tetrahydropyran by stirring thoroughly, use lithium foil as the lithium source to contact the graphite electrode, and contact for 5 min under a pressure of 0.1 kg to obtain a pre-lithiated graphite electrode with an initial coulombic efficiency of about 110%.
[0058] Step 2, Preparation of nitrided interfacial pre-lithiated graphite electrode: The pre-lithiated graphite electrode from Step 1 is immediately immersed in 10 ml of a 0.5 mol / L ammonium hexafluorozirconate solution, and an interfacial chemical reaction is carried out at 30 °C for 3 min, resulting in the in-situ generation of Li3N / Li on the graphite electrode surface. x N y Composite interface layer;
[0059] Step 3, electrode drying treatment: The pre-lithiated graphite electrode with nitride interface from step 2 is dried at 80°C for 2 hours under an argon atmosphere to completely remove residual solvent and obtain a structurally stable lithium nitride-rich graphite composite electrode.
[0060] Example 8: A lithium-ion battery, the preparation steps are as follows:
[0061] 1) Prepare the following materials in advance in a glove box filled with high-purity argon: lithium nitride-rich graphite composite electrode obtained in Example 1, positive electrode shell CR2025, negative electrode shell CR2025, spring sheet 15.4mm×1.1mm, gasket 15.8mm×0.5mm, LiPF6 (EC / DEC=1:1 vol%) as electrolyte, 1mL pipette, polypropylene diaphragm, and lithium sheet 16mm×0.6mm.
[0062] 2) Assemble the prepared materials in the following order: negative electrode shell, graphite electrode, electrolyte, separator electrolyte, lithium sheet, gasket, spring sheet, and positive electrode shell to form a CR2025 button lithium-ion battery.
[0063] Comparative Example 1: The only difference between this comparative example and Example 1 is that this comparative example does not use dielectric pre-lithiation treatment and interface nitriding treatment, that is, the original graphite electrode is used as the comparative example. Figure 5 The results of the first charge-discharge test are for the pre-lithiated graphite electrode with interface nitridation in Example 1 and the original graphite electrode in Comparative Example 1.
[0064] Comparative Example 2: The only difference between this comparative example and Example 1 is that this comparative example only uses the dielectric contact pre-lithiation in step 1, that is, it does not use pre-lithiated graphite to prepare the nitride interface as a comparative example. Figure 6 The results of the first charge-discharge tests are shown for the interface-nitrided pre-lithiated graphite electrode of Example 1 and the original graphite electrode of Comparative Example 2. Figure 7 The results show the cycle performance of the pre-lithiated graphite electrode with interface nitridation in Example 1 and the original graphite electrode in Comparative Example 1.
[0065] Comparative Example 3: The only difference between this comparative example and Example 1 is that this comparative example uses 1M conventional electrolyte as the contact pre-lithiation medium in step 1, i.e., 1M LiPF6 (EC / DEC=1:1 vol%) as the comparative example. Figure 8 The results of the first charge-discharge tests are for the pre-lithiated graphite electrode with interface nitridation in Example 2 and the graphite electrode with 1M LiPF6 (EC / DEC=1:1 vol%) electrolyte as the contact pre-lithiation medium in Comparative Example 3. Carbonate solvents are prone to excessive decomposition during the pre-lithiation process, and the pre-lithiation efficiency is relatively lower than that of the carbonyl aromatic hydrocarbon medium in the examples.
[0066] Obviously, the above embodiments are only some embodiments of the present invention, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.
Claims
1. A method for preparing graphite electrodes to enhance fast charging through pre-lithiation and interface nitridation, characterized in that, Includes the following steps: S1: The graphite electrode and the lithium source are brought into pressure contact with each other in a carbonyl aromatic hydrocarbon medium to form a pre-lithiated graphite electrode with highly reactive lithium on the surface. S2: Immediately immerse the pre-lithiated graphite electrode in a nitrogen-containing precursor solution to generate Li3N / Li in situ on the graphite electrode surface. x N y Composite interface layer, Li3N / Li x N y The composite interface layer and the graphite substrate are covalently bonded by CN-Li to form a stable interface structure SEI; S3: Dry the graphite electrode under an argon or nitrogen atmosphere to completely remove residual solvent and obtain a structurally stable lithium nitride-rich graphite composite electrode.
2. The method for preparing a graphite electrode with improved fast charging through pre-lithiation and interface nitridation regulation according to claim 1, characterized in that, The graphite electrode has a concentration of 2 mg / cm³. 2 The lithium source is artificial graphite, natural graphite, mesophase carbon microspheres, soft carbon, or hard carbon; the lithium source is a smooth-surfaced metallic lithium foil, lithium strip, or lithium film deposited on a carrier.
3. The method for preparing a graphite electrode with improved fast charging through pre-lithiation and interface nitridation control according to claim 1, characterized in that, The carbonyl aromatic hydrocarbon medium is an ether reagent of carbonyl aromatic hydrocarbon with a concentration of 0.01 mol / L to 1 mol / L. When the carbonyl aromatic hydrocarbon medium comes into contact with the lithium source, it can rapidly form a highly active and migratory lithium-aromatic hydrocarbon complex. The lithium-aromatic hydrocarbon complex acts as a charge carrier, enabling rapid and spatially uniform bulk pre-intercalation of lithium ions from the lithium source into the interior of the graphite electrode, forming a pre-lithiated graphite electrode with a highly reactive lithium surface.
4. The method for preparing a graphite electrode with improved fast charging through pre-lithiation and interface nitridation control according to claim 1, characterized in that, The carbonyl aromatic hydrocarbon molecules constituting the carbonyl aromatic hydrocarbon medium include one or more combinations of benzophenone, tetrahydronaphthone, anthrone, phenanthrone, 9-fluorenone, acetophenone, and naphthyl acetophenone, and the ether solvent is selected from one or more combinations of dimethoxyethane, tetrahydrofuran, 2-methyltetrahydrofuran, tetrahydropyran, and 1,3-dioxolane.
5. The method for preparing a graphite electrode with improved fast charging through pre-lithiation and interface nitridation control according to claim 3, characterized in that, The pre-lithiation degree of the pre-lithiated graphite electrode is achieved by controlling the contact time between the graphite electrode and the lithium source, the applied pressure, and the medium concentration to achieve an initial coulombic efficiency of 90%-120%. The contact time is 1-30 minutes and the applied pressure is 0.1-1 kg.
6. The method for preparing a graphite electrode with improved fast charging through pre-lithiation and interface nitridation control according to claim 1, characterized in that, The nitrogen-containing precursor solution is at least one of the following: a functionalized ionic liquid containing cyano, amino, or azide groups, a nitrogen-doped carbon precursor, or a solution of a polydentate nitrogen ligand with coordination ability: including one or more of tetramethylethylenediamine, ammonium hexafluorozirconate, N,N-dimethylethylenediamine, diphenyl azidophosphate, ammonium hexafluorotitanate, ethylenediaminetetraacetic acid, and melamine.
7. The method for preparing a graphite electrode with improved fast charging through pre-lithiation and interface nitridation control according to claim 6, characterized in that, The pre-lithiated graphite electrode was immersed in a nitrogen-containing precursor solution and subjected to interfacial chemical reaction at 20-50℃. The concentration of the nitrogen-containing precursor solution was 0.05mol / L~2mol / L, and the reaction time was 1min~30min.
8. The method for preparing a graphite electrode with improved fast charging through pre-lithiation and interface nitridation control according to claim 1, characterized in that, The inert atmosphere is argon or nitrogen; the drying temperature is 60-120℃, and the drying time is 2-12 hours to ensure that the residual solvent in the electrode is fully removed without affecting the electrode structure and performance.
9. A pre-lithiated graphite electrode with interfacial nitridation obtained by the preparation method of claim 1 as a negative electrode material.
10. A lithium-ion battery, characterized in that, According to claim 1, the pre-lithiated graphite electrode with interface nitridation is characterized in that the initial coulombic efficiency of the composite electrode is ≥95%, and the capacity retention rate is ≥90% after 500 cycles at 1C rate.