A pre-lithiation method for lithium-ion battery

Abstract

The present invention discloses a pre-lithiation method for a lithium-ion battery. The battery positive electrode material is lithium iron phosphate or a mixture of lithium iron phosphate and one or more of lithium nickel cobalt manganese oxide and lithium iron manganese phosphate. The pre-lithiation material and a redox shuttle agent material are used as additives. These two additives can initiate a redox shuttle reaction and a pre-lithiation reaction at a specific voltage of 3.8-4.0V, effectively reducing the delithiation voltage of the pre-lithiation additive. The heat energy generated by the redox shuttle reaction enables the pre-lithiation agent to more fully exert its lithium replenishment effect, effectively compensating for the lithium loss caused by the formation of a solid-electrolyte interface film (SEI film) of the positive electrode material during the first charge and discharge, thereby effectively improving the capacity of the positive electrode and achieving higher energy density requirements.

Description

Technical Field

[0001] The present invention relates to the field of lithium ion batteries, in particular to a pre-lithiation method for lithium ion batteries. Background Art

[0002] During the initial charge of a lithium-ion battery, the organic electrolyte undergoes reduction and decomposition on the surface of the negative electrode, such as graphite, forming a solid electrolyte interface (SEI) film. This consumes lithium from the positive electrode, resulting in a low first-cycle Coulombic efficiency (ICE), reducing the capacity of the lithium-ion battery and thus affecting its energy density. Therefore, how to compensate for the lithium ions consumed during the SEI film formation process has always been a product development goal in the lithium battery industry.

[0003] From the perspective of technical paths, the current mainstream lithium replenishment solutions can be divided into two categories: one is negative electrode lithium replenishment, which is mainly inert metal lithium powder, metal lithium foil or lithium compounds; the other is positive electrode lithium replenishment, which is mainly some lithium-containing oxides.

[0004] A search of existing patent literature revealed that CN 110212184 A discloses a pre-lithiation method for carbon anode materials for lithium-ion batteries. The method comprises the following steps: preparing 1-10% lithium carbonate powder and 90-99% carbon anode material; adding the lithium carbonate powder and solvent to a ball mill for liquid-phase ball milling to obtain a fine powder of 100-1000 nm; adding the carbon anode material to the ball mill and stirring to disperse it to obtain a well-dispersed slurry of graphite mixed with lithium carbonate powder; using a gauze screen to remove zirconium oxide balls from the slurry to obtain a powder slurry with good consistency; and drying the powder slurry by spray drying to obtain a pre-lithiated graphite anode material. However, the preparation of pre-lithiated anode materials is more complex than conventional battery manufacturing, and the high price of lithium carbonate hinders the efficiency and cost reduction of large-scale industrial production.

[0005] CN 113394371 A discloses a lithium-replenishing slurry, a positive electrode sheet, and a lithium-ion battery. The lithium-replenishing slurry and the positive electrode slurry are dispersed and mixed separately, avoiding the problem of directly adding the lithium-replenishing material to the positive electrode slurry, which causes the positive electrode slurry to be difficult to disperse, easily agglomerated, and gelled. The lithium-replenishing slurry formed by the lithium-replenishing material, conductive agent, and binder added by the present invention can achieve a better dispersion effect. After being applied to the positive electrode coating, the impedance of the resulting positive electrode sheet is lower, and the lithium-replenishing effect is more excellent. However, the lithium-replenishing slurry and the positive electrode slurry are applied separately, and the electrode sheet manufacturing process is more complicated than the conventional battery manufacturing process, and the electrode sheet is layered. After the first charge, the lithium-replenishing layer will generate a layer of inactive substances with very low conductivity, which can easily affect the battery capacity. In addition, the two slurries consume a lot of inactive substances such as binders, which is not conducive to improving the battery energy density. Summary of the Invention

[0006] The purpose of the present invention is to provide a pre-lithiation method for lithium-ion batteries, in order to solve the problems of complex lithium replenishment technology and insufficient lithium replenishment, thereby effectively improving the capacity of the positive electrode and achieving higher energy density requirements.

[0007] The present invention relates to a pre-lithiation method for a lithium ion battery, wherein the lithium ion battery contains a redox shuttle agent and a pre-lithiation agent; the positive electrode active material of the lithium ion battery contains lithium iron phosphate;

[0008] The redox shuttle agent is added in an amount of 0.1%-10% of the total mass of the positive electrode sheet, the negative electrode sheet or the electrolyte; and the solid content of the pre-lithium agent in the positive electrode sheet is 0.1%-10%.

[0009] The present invention utilizes the synergistic effect of a redox shuttle agent and a pre-lithiation agent within a specific voltage range to enable the battery to achieve sufficient pre-lithiation and achieve quantitative control, thereby preparing a high specific capacity battery.

[0010] As an embodiment, the pre-lithium agent is one or more of lithium ferrite, lithium phosphate, lithium oxalate, and lithium carbonate.

[0011] As an embodiment, the redox shuttle agent is one or more of 2,5-di-tert-butyl-1,4-dimethoxybenzene, 3,5-di-tert-butyl-1,2-dimethoxybenzene, 4-tert-butyl-1,2-dimethoxybenzene, naphthalene, anthracene, thianthrene, and anisole.

[0012] As one embodiment, the mass ratio of the redox shuttle agent to the pre-lithiation agent is 0.1-10:0.1-10. A more preferred mass ratio is 2.0-5.0:1.0-5.0. In some embodiments, the mass ratio of the redox shuttle agent to the pre-lithiation agent when added simultaneously to the positive electrode sheet is 2.0-5.0:1.0-5.0.

[0013] As an embodiment, the mass percentage content of lithium iron phosphate in the positive electrode active material of the lithium ion battery is 60% to 100%.

[0014] As an embodiment, the positive electrode active material of the lithium-ion battery is lithium iron phosphate, or a mixture of lithium iron phosphate and one or more of lithium nickel cobalt manganese oxide, lithium manganese oxide, lithium cobalt oxide, and lithium manganese iron phosphate.

[0015] As an embodiment, the negative electrode active material of the lithium ion battery is graphite, silicon-carbon negative electrode or other metal negative electrode materials.

[0016] As an embodiment, the electrolyte is an organic solution containing at least one lithium salt, and the lithium salt is LiPF6, LiFSI, LiBF6, or LiClO4.

[0017] As an embodiment, a lithium-ion battery containing a redox shuttle agent and a pre-lithiation agent is replenished with lithium using the following steps:

[0018] S1. A lithium-ion battery containing a redox shuttle agent and a pre-lithium agent is aged and allowed to stand for 12-24 hours;

[0019] S2. Precharge the battery to 3.5V-3.7V with a constant current of 0.01C-0.05C, then charge it to 3.8V-3.95V with a constant current of 0.01C-0.02C. Continue constant current charging. At this time, the battery will be constant between 3.85V-3.95V or a pre-lithium agent delithiation voltage platform will appear. The pre-lithium agent begins to delithium. According to the amount of pre-lithium, the constant current charging time t is calculated. After obtaining a constant pre-lithium amount, charge the battery to 4.4V-4.5V with a constant current of 0.03C-0.05C and let it stand for 30-60 minutes.

[0020] S3. Discharge the battery with a constant current of 0.1C-1C to the lower discharge voltage limit and let it stand for 30-60 minutes.

[0021] According to the above steps S1, S2, and S3, the lithium replenishment of the battery is completed, and the battery can be used according to the normal steps. Step S2 can be selected to partially delithiate or completely delithiate. When the pre-lithium agent is partially delithiated, the constant current charging time t (h) and the current size I (A) meet 0 ≤ It / 10 ≤ Q 预锂剂 , when the pre-lithium agent is completely delithiated, It / 10≥Q 预锂剂 , Q 预锂剂 (Ah) is the total capacity of the pre-lithium agent. In step S3, for lithium iron phosphate batteries, the lower discharge voltage is usually 2-2.5V.

[0022] The present invention also relates to a method for preparing a lithium-ion battery comprising the aforementioned pre-lithium method, the method comprising the following steps:

[0023] S1, preparing a positive electrode sheet;

[0024] S1-1, mixing a positive electrode active material, a binder, a conductive agent, a redox shuttle agent, and a pre-lithium agent, using N-methylpyrrolidone as a dispersion medium, stirring, and preparing a positive electrode slurry, and coating the mixture on a positive electrode current collector to form a positive electrode sheet A1;

[0025] or,

[0026] S1-2, mixing the positive electrode active material, binder, conductive agent, and pre-lithium agent, using N-methylpyrrolidone as a dispersion medium, stirring to prepare a positive electrode slurry, and coating the mixture on the positive electrode current collector to form a positive electrode sheet A2;

[0027] S2, preparing the negative electrode sheet;

[0028] S2-1, mixing graphite, a binder, a conductive agent, and a redox shuttle agent, using N-methylpyrrolidone as a dispersion medium, stirring, and preparing a negative electrode slurry, and coating the mixture on a negative electrode current collector to form a negative electrode sheet B1;

[0029] or,

[0030] S2-2, mixing graphite, a binder, and a conductive agent, using N-methylpyrrolidone as a dispersion medium, stirring, and preparing a negative electrode slurry, and coating the mixture on a negative electrode current collector to form a negative electrode sheet B2;

[0031] S3,

[0032] S3-1, assembling the positive electrode sheet A1 and the negative electrode sheet B2 into a dry cell, injecting liquid and allowing to stand;

[0033] Or, S3-2, assembling the positive electrode sheet A2 and the negative electrode sheet B1 into a dry cell, injecting liquid and allowing to stand;

[0034] Or, S3-3, assembling the positive electrode sheet A2 and the negative electrode sheet B2 into a dry cell, injecting liquid and letting it stand; adding a redox shuttle agent to the electrolyte injected.

[0035] As an embodiment, in step S1-1, the mass ratio of the positive electrode active material, the binder, the conductive agent, the redox shuttle agent, and the pre-lithiation agent is 73-97:1-3:1.8-4:0.1-10:0.1-10.

[0036] As an embodiment, in step S2-1, the mass ratio of graphite, binder, conductive agent, and redox shuttle agent is 85-97:2-3:0-2:0.1-10.

[0037] As an embodiment, in step S1-2, the mass ratio of the positive electrode active material, the binder, the conductive agent, and the pre-lithium agent is 83-97:1-3:1.9-4:0.1-10.

[0038] As an embodiment, in step S2-2, the mass ratio of graphite, binder, and conductive agent is 95-98:2-3:0-2.

[0039] As an embodiment, the electrolyte in steps S3-1 and 3-2 does not contain a redox shuttle agent; the electrolyte in step S3-3 contains a redox shuttle agent, and the redox shuttle agent is added in an amount of 0.1% to 10% of the total mass of the positive electrode sheet, the negative electrode sheet or the electrolyte.

[0040] The high specific capacity lithium-ion battery obtained by the aforementioned lithium-ion battery pre-lithiation method also falls within the protection scope of the present invention.

[0041] Compared with the prior art, the present invention has the following beneficial effects:

[0042] 1) Fully utilizing the synergistic effect of the pre-lithiation agent and the redox shuttle additive within a specific voltage range of 3.8V-3.95V, the battery is charged with a small current, and when the battery reaches 3.85V, it enters the pre-lithiation range. By controlling the current and charging time, quantitative pre-lithiation is achieved; because the redox shuttle additive converts chemical energy into thermal energy under the self-equilibrium voltage, the heat generated is conducive to the delithiation of the pre-lithiation agent, the polarization becomes smaller, and the gram capacity of the pre-lithiation agent is more fully utilized.

[0043] 2) In addition, since the upper limit voltage of pure lithium iron phosphate batteries during normal use is 3.65V-3.8V, pre-lithiation will not be activated. Therefore, when the battery contains appropriate pre-lithiation agents and redox shuttle additives, the cyclic use within the normal voltage range will not be affected. Moreover, due to the presence of the redox shuttle agent, the delithiation voltage of the pre-lithiation agent is reduced to a certain extent, which is beneficial to maintaining the stability of the electrolyte during the first charge. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] Other features, objects and advantages of the present invention will become more apparent upon reading the detailed description of non-limiting embodiments with reference to the following drawings:

[0045] Figure 1 The first charge curves of the batteries after pre-lithiation of Example 1, Example 2 and Comparative Example 1 are marked as A1, A2, and B1 respectively;

[0046] Figure 2 The discharge capacity test curves of the batteries after pre-lithiation of Example 1, Example 2 and Comparative Example 1 are marked as A1, A2 and B1 respectively. DETAILED DESCRIPTION

[0047] The present invention is described in detail below with reference to the examples. The following examples will help those skilled in the art to further understand the present invention, but are not intended to limit the present invention in any form. It should be noted that, for those skilled in the art, several adjustments and improvements can be made without departing from the present invention. These all fall within the scope of protection of the present invention. In addition, the parameters of the specific processes in the following examples also need to be adjusted to appropriate parameters according to actual conditions.

[0048] The present invention provides a pre-lithiation method, which includes the synergistic effect of a redox shuttle agent and a pre-lithiation agent.

[0049] The pre-lithium agent is used to compensate for the irreversible lithium loss caused by the formation of a passivation film during battery formation, as well as the active lithium loss during cycling. The pre-lithium agent contains at least one of lithium ferrite, lithium phosphate, lithium oxalate, and lithium carbonate.

[0050] The redox shuttle agent's ability to convert self-equalizing voltage and chemical energy into thermal energy ensures more complete delithiation of the pre-lithiation agent during the initial charge process. The redox shuttle agent is selected from one or more of 2,5-di-tert-butyl-1,4-dimethoxybenzene, 3,5-di-tert-butyl-1,2-dimethoxybenzene, 4-tert-butyl-1,2-dimethoxybenzene, naphthalene, anthracene, thianthrene, and anisole.

[0051] Test methods and test results:

[0052] Pre-lithiation method: 1) For Examples 1-12 and Comparative Examples 1-6, the prepared batteries were allowed to stand at 25°C ± 3°C for 12 hours, charged at a constant current of 0.05C to 3.65V, and then charged at a constant current of 0.02C to 3.85V. Constant current charging was continued. At this time, the battery would show a pre-lithiation voltage platform, and the pre-lithiation agent began to delithiate. The battery was then charged at a constant current for 1 hour, and then charged at a constant current of 0.03C to 4.4V, and allowed to stand for 30 minutes. The battery was then discharged at a constant current of 0.1C to 2V, and allowed to stand for 30 minutes.

[0053] Discharge capacity test: After completing the above steps, let the battery rest for 5 minutes, charge it at a constant current of 0.1C to 3.8V; let it rest for 5 minutes, then discharge it at a constant current of 0.1C to 2.0V, and record the discharge specific capacity (mAh / g). Discharge specific capacity = discharge capacity / mass of positive electrode active material.

[0054] The present application will be further described below through some specific embodiments.

[0055] Example 1

[0056] LiFePO4, carbon black, PVDF, 2,5-di-tert-butyl-1,4-dimethoxybenzene, and lithium ferrite were mixed in a mass ratio of 90:2.5:2.5:3.0:2.0 and loaded into a ball mill. N-methylpyrrolidone was used as a dispersion medium, and the mixture was stirred to prepare a positive electrode slurry, which was then coated on the positive electrode current collector and dried and rolled to obtain a positive electrode sheet.

[0057] Graphite, PVDF and carbon black were mixed in a mass ratio of 96:2:2, and N-methylpyrrolidone was used as a dispersion medium. The mixture was stirred and prepared into a negative electrode slurry, which was then coated on a negative electrode current collector. The negative electrode sheet was obtained after drying and roller pressing.

[0058] Example 2

[0059] The preparation method of Example 1 is adopted, except that its positive electrode active material is a mixture of LiMnFePO4 and LiFePO4, the mass ratio of which is 6:4, and the mass ratio of (LiMnFePO4+LiFePO4), carbon black, PVDF, 2,5-di-tert-butyl-1,4-dimethoxybenzene, and lithium ferrite is 90:2.5:2.5:3.0:2.0.

[0060] Example 3

[0061] The preparation method of Example 1 was adopted, except that the mass ratio of LiFePO4, carbon black, PVDF, 2,5-di-tert-butyl-1,4-dimethoxybenzene, and lithium ferrite was 91.9:2.5:2.5:3.0:0.1.

[0062] Example 4

[0063] The preparation method of Example 1 was adopted, except that the mass ratio of LiFePO4, carbon black, PVDF, 2,5-di-tert-butyl-1,4-dimethoxybenzene, and lithium ferrite was 87:2.5:2.5:3.0:5.0.

[0064] Example 5

[0065] The preparation method of Example 1 was adopted, except that the mass ratio of LiFePO4, carbon black, PVDF, 2,5-di-tert-butyl-1,4-dimethoxybenzene, and lithium ferrite was 82:2.5:2.5:3.0:10.0.

[0066] Example 6

[0067] The preparation method of Example 1 was adopted, except that 2,5-di-tert-butyl-1,4-dimethoxybenzene was added to the electrolyte with a mass fraction of 2%, and the mass ratio of LiFePO4, carbon black, PVDF, and lithium ferrite in the positive electrode was 93:2.5:2.5:2.0.

[0068] Example 7

[0069] The preparation method of Example 6 was adopted, except that the mass fraction of 2,5-di-tert-butyl-1,4-dimethoxybenzene was 5%.

[0070] Example 8

[0071] The preparation method of Example 1 was adopted, except that 2,5-di-tert-butyl-1,4-dimethoxybenzene was added to the negative electrode slurry, graphite, PVDF, carbon black, and 2,5-di-tert-butyl-1,4-dimethoxybenzene were mixed in a mass ratio of 94:2.0:2.0:2.0, and the mass ratio of LiFePO4, carbon black, PVDF, and lithium ferrite in the positive electrode was 93:2.5:2.5:2.0.

[0072] Example 9

[0073] The preparation method of Example 8 was adopted, except that graphite, PVDF, carbon black, and 2,5-di-tert-butyl-1,4-dimethoxybenzene were mixed in a mass ratio of 91:2.0:2:5.0.

[0074] Example 10

[0075] The preparation method of Example 6 was adopted, except that the redox shuttle agent was 3,5-di-tert-butyl-1,2-dimethoxybenzene.

[0076] Example 11

[0077] The preparation method of Example 6 is adopted, except that the pre-lithium agent is lithium oxalate.

[0078] Example 12

[0079] The preparation method of Example 6 is adopted, except that the pre-lithium agent is lithium carbonate.

[0080] Comparative Example 1

[0081] LiFePO4, carbon black, PVDF, and 2,5-di-tert-butyl-1,4-dimethoxybenzene were mixed in a mass ratio of 90:2.5:2.5:5.0 and loaded into a ball mill. N-methylpyrrolidone was used as a dispersion medium, and the mixture was stirred to prepare a negative electrode slurry, which was then coated on the positive electrode current collector and dried and rolled to obtain a positive electrode sheet.

[0082] Graphite, PVDF and carbon black were mixed in a mass ratio of 96:2:2, and N-methylpyrrolidone was used as a dispersion medium. The mixture was stirred and prepared into a negative electrode slurry, which was then coated on a negative electrode current collector. The negative electrode sheet was obtained after drying and roller pressing.

[0083] After assembly, a lithium-ion battery is obtained.

[0084] Comparative Example 2

[0085] The same preparation method as Comparative Example 1 was adopted, except that the positive electrode active material was a mixture of LiMnFePO4 and LiFePO4 with a mass ratio of 6:4, and the mass ratio of (LiMnFePO4+LiFePO4), carbon black, PVDF, and 2,5-di-tert-butyl-1,4-dimethoxybenzene was 90:2.5:2.5:5.0.

[0086] Comparative Example 3

[0087] The same preparation method as Comparative Example 1 was adopted, except that no redox shuttle agent was added, and a pre-lithium agent was added, and the mass ratio of LiFePO4, carbon black, PVDF, and lithium ferrite was 90:2.5:2.5:5.0.

[0088] Comparative Example 4

[0089] The same preparation method as Comparative Example 1 was adopted, except that no redox shuttle agent was added, and the mass ratio of LiFePO4, carbon black, and PVDF was 95:2.5:2.5.

[0090] Comparative Example 5

[0091] The same preparation method as in Example 1 is adopted, except that the pre-lithium agent is lithium nitride.

[0092] Comparative Example 6

[0093] The same preparation method as in Example 1 is adopted, except that the pre-lithium agent is lithium hydride.

[0094] Comparative Example 7

[0095] The same manufacturing method as Example 2 is adopted, except that the pre-lithiation method is: charging to 3.85V at a constant current of 0.03C, continuing constant current charging for 1h, and then charging to 4.4V at a constant current of 0.3C.

[0096] The positive and negative electrodes of the above examples and comparative examples were assembled into dry cells, which were then packaged and allowed to stand for 24 hours to obtain lithium-ion batteries for testing. The electrolyte formulation was 1M LiPF6 electrolyte, and the solvents EC:EMC:DMC were in a volume ratio of 1:1:1.

[0097] Table 1 shows the test results of the batteries of the embodiment and the comparative example. It can be seen from the test results that the simultaneous addition of the redox shuttle agent and the pre-lithium agent can significantly enhance the performance of the pre-lithium agent and improve the discharge specific capacity of the lithium-ion battery.

[0098] Table 1

[0099]

[0100]

[0101] Figure 1 The first charge curve diagram of the battery after pre-lithiation of Example 1, Example 2 and Comparative Example 1 is shown. Figure 2 is the discharge capacity test curve; Figure 1 It can be seen that the first charge curves A1 and A2 of the battery with the pre-lithium agent added have obvious inflection points between 3.85V and 3.95V, which are the starting points of the delithiation voltage platform of the pre-lithium agent. The battery without the pre-lithium agent has only the self-balanced voltage platform of the redox shuttle agent in this range. Under the pre-lithium method of the present invention, the pre-lithium agent can be fully utilized, and the charge specific capacity is increased by more than 10mAh / g. Figure 2It can be seen that the battery discharge capacity is significantly improved after pre-lithiation, indicating that the added pre-lithiation agent plays a role in compensating for the active lithium lost in the battery formation process and improving the reversible capacity of the battery.

[0102] In summary, the present invention uses both pre-lithium materials and redox shuttle materials as additives. These two additives can initiate redox shuttle reactions and pre-lithium reactions at a specific voltage of 3.8V-4.0V, which can effectively reduce the delithiation voltage of the pre-lithium additive. The heat energy generated by the redox shuttle reaction enables the pre-lithium agent to more fully exert its lithium replenishment effect, effectively compensating for the lithium loss caused by the formation of the solid-electrolyte interface film (SEI film) of the positive electrode material during the first charge and discharge, thereby effectively improving the capacity of the positive electrode and achieving higher energy density requirements.

[0103] The above describes the specific embodiments of the present invention. It should be understood that the present invention is not limited to the above specific embodiments, and those skilled in the art may make various variations or modifications within the scope of the claims, which do not affect the essence of the present invention.

Claims

1. A lithium-ion battery pre-lithiation method, characterized in that: The lithium-ion battery contains a redox shuttle agent and a pre-lithium agent; the positive electrode active material of the lithium-ion battery contains lithium iron phosphate; The redox shuttle agent is added to the positive electrode sheet, the negative electrode sheet or the electrolyte in an amount of 0.1% to 10% of the total mass; the solid content of the pre-lithium agent in the positive electrode sheet is 0.1% to 10%; The lithium-ion battery containing the redox shuttle agent and the pre-lithium agent is replenished with lithium using the following steps: S1. A lithium-ion battery containing a redox shuttle agent and a pre-lithium agent is aged and allowed to stand for 12-24 hours; S2. Precharge the battery to 3.5V-3.7V with a constant current of 0.01C-0.05C, then charge it to 3.8V-3.95V with a constant current of 0.01C-0.02C. Continue constant current charging. At this time, the battery will be constant between 3.85V-3.95V or a pre-lithium agent delithiation voltage platform will appear. The pre-lithium agent begins to delithium. According to the amount of pre-lithium, the constant current charging time t is calculated. After obtaining a constant pre-lithium amount, charge the battery to 4.4V-4.5V with a constant current of 0.03C-0.05C and let it stand for 30 minutes to 60 minutes. S3. Discharge the battery with a constant current of 0.1C-1C to the lower discharge voltage limit and let it stand for 30 minutes to 60 minutes.

2. The lithium ion battery pre-lithiation method according to claim 1, wherein The pre-lithium agent is one or more of lithium ferrite, lithium phosphate, lithium oxalate, and lithium carbonate.

3. The lithium ion battery pre-lithiation method according to claim 1, wherein The redox shuttle agent is one or more of 2,5-di-tert-butyl-1,4-dimethoxybenzene, 3,5-di-tert-butyl-1,2-dimethoxybenzene, 4-tert-butyl-1,2-dimethoxybenzene, naphthalene, anthracene, thianthrene, and anisole.

4. The lithium ion battery pre-lithiation method according to claim 1, wherein The mass ratio of the redox shuttle agent to the pre-lithium agent is 0.1-10:0.1-10.

5. The lithium-ion battery pre-lithiation method according to claim 4, wherein: The mass ratio of the redox shuttle agent to the pre-lithium agent is 2.0-5.0:1.0-5.

0.

6. The lithium-ion battery pre-lithiation method according to claim 1, wherein The mass percentage of lithium iron phosphate in the positive electrode active material of the lithium ion battery is 60% to 100%.

7. The lithium-ion battery pre-lithiation method according to claim 1, characterized in that: The positive electrode active material of the lithium ion battery is lithium iron phosphate, or a mixture of lithium iron phosphate and one or more of lithium nickel cobalt manganese oxide, lithium manganese oxide, lithium cobalt oxide, and lithium manganese iron phosphate.

8. The lithium-ion battery pre-lithiation method according to claim 1, wherein: The negative electrode active material of the lithium-ion battery is graphite, silicon-carbon negative electrode or other metal negative electrode materials; the electrolyte is an organic solution containing at least one of LiPF6, LiFSI, LiBF6, and LiClO4.

9. A high specific capacity battery obtained by the lithium-ion battery pre-lithiation method according to claim 1.

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