Lithium ion battery pole piece, battery cell and battery

Abstract

The invention relates to the technical field of lithium batteries, and discloses a lithium ion battery pole piece, a battery cell and a battery. The solid electrolyte and the lithium-rich solid electrolyte contain variable valence metal elements M, the valence state of the variable valence metal elements M in the solid electrolyte is + 3 to + 6, and the valence state of the variable valence metal elements M in the lithium-rich solid electrolyte is + 2 to + 5. The lithium ion battery assembled by the pole piece has better safety performance and longer cycle life.

Description

Lithium-ion battery electrodes, cells and batteries Technical Field

[0001] This invention relates to the field of lithium battery technology, specifically to a lithium-ion battery electrode, cell, and battery. Background Technology

[0002] Lithium-ion batteries are widely used in new energy vehicles, 3C consumer electronics, energy storage, and other fields. To meet the market's continuous pursuit of high specific energy and high safety, improving their various performance indicators is crucial. During the first charge and discharge process of a lithium-ion battery, the formation of the SEI film on the negative electrode side leads to irreversible loss of active lithium, inevitably reducing the battery's energy density and cycle life. Currently, the effective strategy to compensate for this loss is to add lithium replenishing agents to the positive and negative electrode materials. Mainstream lithium replenishing agents include: binary lithium-containing compounds such as LiN3, Li3N, Li2O, Li2S, Li2Se, LiF, and Li3P, with a theoretical lithium replenishment capacity of up to 1000 mAh / g; ternary lithium-containing compounds such as Li2NiO2, Li5FeO4, Li6CoO4, Li2MoO3, and Li8ZrO6, with lithium replenishment capacities mostly exceeding 300 mAh / g; and organic lithium-containing compounds such as Li2C2O4, Li2C4O4, and Li2DHBN.

[0003] Despite the wide variety of lithium supplements and their relatively mature technology, challenges remain, including high complete decomposition potential, gas production during decomposition, high residual alkali levels, and poor air stability. To improve battery safety, introducing inorganic solid-state electrolytes into traditional lithium-ion batteries to achieve gradual solid-state transformation has become an inevitable trend. Compared to flammable traditional organic electrolytes, solid-state electrolytes are non-flammable and also possess lithium-ion transport capabilities, significantly improving battery safety. However, the introduction of solid-state electrolytes typically leads to a decrease in battery energy density.

[0004] Currently, introducing solid-state electrolytes and lithium replenishers separately into batteries is a common industry practice. For example, CN115954615A describes co-coating solid-state electrolytes and lithium powder onto a separator under inert gas; CN119751058 describes constructing a core-shell structure with lithium replenishers and solid-state electrolytes. However, existing technologies essentially still introduce solid-state electrolytes and lithium replenishers as two physically isolated independent substances into the battery cell, representing a simple surface-physical combination. This approach not only increases the complexity of the material structure but also makes the manufacturing process more cumbersome. Furthermore, the lithium-containing compounds used in existing technologies, after completing their lithium replenishment function, no longer possess any other functional advantages and become redundant additives in the battery cell, offering no subsequent beneficial effects on the battery. Summary of the Invention

[0005] The purpose of this invention is to overcome the problems of high decomposition potential of lithium-ion materials, gas production, and battery performance degradation caused by decomposition byproducts in existing technologies. This invention provides a lithium-ion battery electrode, cell, and battery. When applied to lithium-ion batteries, this electrode can effectively improve the safety performance and extend the lifespan of lithium-ion batteries.

[0006] To achieve the above objectives, the present invention provides a lithium-ion battery electrode, wherein the electrode contains a lithium-rich solid electrolyte; the solid electrolyte and the lithium-rich solid electrolyte contain a variable valence metal element M, wherein the variable valence metal element M in the solid electrolyte has a valence state of +3 to +6, and the variable valence metal element M in the lithium-rich solid electrolyte has a valence state of +2 to +5.

[0007] A second aspect of the present invention provides a battery cell comprising the electrode sheets provided in the first aspect of the present invention.

[0008] A third aspect of the present invention provides a battery comprising the battery cell provided in the second aspect of the present invention.

[0009] The beneficial effects of this invention, achieved through the above technical solution, are as follows: The specific lithium-rich solid electrolyte material provided by this invention, on the one hand, possesses the effects of traditional lithium replenishing agents, replenishing irreversible lithium loss during the first charge-discharge process and improving the battery's energy density; on the other hand, it has the advantages of solid electrolytes, including lithium-ion conduction, electrochemical stability, and safety (non-flammability). Therefore, its introduction into lithium-ion batteries can replace both lithium replenishing agents and inorganic solid electrolytes. Furthermore, during the first charge, the low-valence cations at the center of the crystal structure of the lithium-rich solid electrolyte material provided by this invention tend to form high-valence cations to maintain structural stability. This makes it easier for lithium ions in the crystal structure to escape and migrate to the negative electrode side to form an SEI film or participate in negative electrode lithium intercalation, replenishing the loss of active lithium in the positive electrode material; that is, forming a stable fast-ion conductor solid electrolyte material. During subsequent charge and discharge processes, due to the inherent stability of the material, lithium ions will not be re-intercalated into the solid electrolyte, consuming reversible active lithium. Instead, they remain in the electrode as a solid electrolyte, serving as both a fast ion conductor and a safety additive that significantly improves the cell's thermal stability and needle penetration stability. This lithium-rich solid electrolyte effectively enhances the cycle stability and rate performance of lithium-ion batteries as a lithium replenishment agent. Furthermore, it exhibits low decomposition voltage, no gas generation, and no byproduct production, which is beneficial to the safety performance of lithium-ion batteries. Attached Figure Description

[0010] Figure 1 shows the XRD pattern of the lithium-rich solid electrolyte prepared in Example 3. Detailed Implementation

[0011] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0012] The present invention provides a lithium-ion battery electrode, wherein the electrode contains a lithium-rich solid electrolyte; the solid electrolyte and the lithium-rich solid electrolyte contain a variable valence metal element M, wherein the valence state of the variable valence metal element M in the solid electrolyte is +3 to +6, for example, +3, +4, +5, +6, and the valence state of the variable valence metal element M in the lithium-rich solid electrolyte is +2, +3, +4, +5.

[0013] In this invention, the lithium-rich solid electrolyte refers to a traditional solid electrolyte in which more lithium ions are doped into the crystal through in-situ chemical methods to fill crystal defects. Unlike traditional solid electrolytes, the lithium-rich solid electrolyte has a lower valence state of the central cation in the crystal structure and a higher lithium content. Before formation, it can be used as a lithium replenishing agent, and after formation, it can be used as a fast ion conductor and a safety additive.

[0014] The electrode provided by this invention has the effect of traditional lithium replenishing agents, which replenishes irreversible lithium loss during the first charge and discharge process and improves the energy density of the battery. On the other hand, it has the advantages of solid electrolytes such as lithium-ion conduction, electrochemical stability, safety and non-flammability. Therefore, its introduction into lithium-ion batteries can replace both lithium replenishing agents and inorganic solid electrolytes.

[0015] The lithium-rich solid electrolyte of this application effectively improves the cycle stability and rate performance of lithium-ion batteries as a chemical lithium supplement. It also has a low decomposition voltage, is not prone to gas generation, and produces no by-products, which is beneficial to the safety performance of lithium-ion batteries. In addition, compared with the lithium foil anode pre-lithiation method, the process of mixing lithium-rich solid electrolyte is less complex and difficult to manufacture, and the cost is more controllable.

[0016] According to the present invention, preferably, the electrode comprises a current collector and an active layer composited on the surface of the current collector, the active layer comprising an active material and a lithium-rich solid electrolyte.

[0017] This invention does not particularly limit the type of current collector, as long as it achieves the technical objective of the invention. According to some preferred embodiments of the invention, the current collector is aluminum foil.

[0018] Preferably, the electrode is a positive electrode and / or a negative electrode, especially a positive electrode.

[0019] Preferably, the active material includes a positive electrode active material and / or a negative electrode active material.

[0020] According to the present invention, preferably, the lithium-rich solid electrolyte is prepared by chemical lithium supplementation from a solid electrolyte.

[0021] According to the present invention, preferably, the content of lithium-rich solid electrolyte in the electrode is 0.1-5% based on the total mass of the active layer, more preferably 1-3%, for example, it can be 1%, 1.3%, 1.5%, 1.8%, 2%, 2.3%, 2.5%, 2.7%, or 3%.

[0022] In this invention, if the content of the lithium-rich solid electrolyte is too high, it will reduce the proportion of active material, resulting in a decrease in the overall energy density of the cell. If it is too low, it will be insufficient to replenish the lithium loss of the active material, thus failing to achieve the lithium replenishment effect, and the safety of the cell will also be reduced.

[0023] This invention does not particularly limit the types of positive and negative electrode active materials; conventional positive and negative electrode active materials in the art can be used. Preferably, the positive electrode active material is selected from at least one of lithium cobalt oxide, nickel-cobalt-manganese ternary materials, lithium iron phosphate, and lithium manganese iron phosphate; preferably, the negative electrode active material is selected from at least one of graphite, silicon, silicon-carbon, and silicon-oxygen.

[0024] According to the present invention, preferably, the variable valence metal element M is selected from at least one of the variable valence metal elements of group IVB, group VB, group VIB, and group VIII, and more preferably from at least one of Ti, V, Cr, Fe, Co, Ni, Nb, Mo, W, and Pt.

[0025] In this invention, the presence of the aforementioned preferred variable-valence metal elements in the solid electrolyte is beneficial for the solid electrolyte to gain electrons and reduce its chemical valence state during the chemical lithium replenishment process. While maintaining structural stability, this allows more lithium ions to enter the crystal structure. The variable-valence elements introduce more lithium ions by adjusting their own valence state.

[0026] According to the present invention, preferably, the molar percentage of the variable valence metal element M in the solid electrolyte is 9-25%.

[0027] This invention does not specifically limit the type of solid electrolyte. Preferably, the solid electrolyte is selected from at least one of NASICON-type, perovskite-type, γ-Li3PO4-type, antifluorite-type, and xenotime-structured solid electrolytes, and more preferably from Li... 1+x Al x Ti 2-x (PO4)3, where 0.3 ≤ x ≤ 0.5; Li 0.32 La 0.56TiO3, LiTiOPO4, Li4TiO4, LiVO3, Li3VO4, Li 3.1 V 0.9 Ge 0.1 At least one of O4.

[0028] In this invention, the preferred solid electrolyte is more likely to be prepared into a lithium-rich solid electrolyte through chemical lithium supplementation, which is beneficial to introduce more lithium ions into the material while reducing its own valence, so as to make it reach a lithium-rich state.

[0029] This invention does not impose a particular limitation on the particle size of the solid electrolyte, as long as it achieves the purpose of this invention. The particle size of the solid electrolyte is 50-500 nm; for example, it can be 50 nm, 80 nm, 100 nm, 120 nm, 150 nm, 180 nm, 200 nm, 250 nm, 300 nm, 320 nm, 350 nm, 380 nm, 400 nm, 450 nm, 480 nm, 500 nm, and any value in between, more preferably 50-250 nm.

[0030] In this invention, the particle size of the solid electrolyte refers to D90. Specifically, in this invention, the particle size of the solid electrolyte refers to the particle size value corresponding to the cumulative particle size distribution of a single solid electrolyte particle, i.e., a primary particle sample, reaching 90%. The size is usually expressed as diameter (for spherical particles) or equivalent particle size (for irregularly shaped particles).

[0031] In this invention, if the particle size of the solid electrolyte is too large, the reaction inside the large particles will be insufficient when the particles react with the organic lithium reagent, and lithium ions will not be able to embed into the interior. If the particle size is too small, there will be dispersion problems during subsequent manufacturing, and the particles will easily agglomerate, which will increase the difficulty of the subsequent process of introducing the electrolyte into the cell.

[0032] According to the present invention, preferably, the chemical composition of the lithium-rich solid electrolyte includes: Li 1+x+y1 Al x Ti 2-x(PO4)3, where 0.3 ≤ x ≤ 0.5 and 1.9 < 1 + x + y1 ≤ 3. For example, x can be 0.3, 0.32, 0.34, 0.36, 0.38, 0.4, 0.42, 0.44, 0.45, 0.46, 0.48, 0.5, or any value in between; y1 can be 0.61, 0.62, 0.63, 0.65, 0.66, 0.68, 0.7, 0.71, 0.73, 0.75, 0.76, 0.77, 0.79, 0.8, 0.82, 0.84, 0.85, 0.87, 0.89, 0.9, 0.91, 0.93, 0.95, 0.96, 0.98, 0.99, 1, 1.01, 1.05, 1.07, 1.08, 1.1, 1.12, 1.15, 1.18, 1.2, 1.22, 1.23, 1.25, 1.27, 1.28, 1.29, 1.3, 1.31, 1.32, 1.3, 1.35, 1.38, 1.4, 1.42, 1.43, 1.45, 1.47, 1.48, 1.49, 1.5, or any value in between; and / or, Li 0.32+y2 La 0.56 TiO3, where 0.38 < y2 ≤ 1. For example, y2 can be 0.39, 0.4, 0.42, 0.44, 0.45, 0.48, 0.5, 0.52, 0.54, 0.55, 0.56, 0.58, 0.59, 0.6, 0.61, 0.62, 0.63, 0.65, 0.66, 0.68, 0.7, 0.71, 0.73, 0.75, 0.76, 0.77, 0.79, 0.8, 0.82, 0.84, 0.85, 0.87, 0.89, 0.9, 0.91, 0.93, 0.95, 0.96, 0.98, 0.99, 1, or any value in between; and / or, Li 1+y3 TiOPO4, where 0 < y3 ≤ 1; and / or, Li 4+y4TiO4, where 0 < y4 ≤ 1. For example, y3 and y4 can be 0.01, 0.03, 0.05, 0.08, 0.1, 0.13, 0.14, 0.16, 0.18, 0.2, 0.22, 0.24, 0.25, 0.26, 0.28, 0.3, 0.33, 0.34, 0.36, 0.38, 0.4, 0.42, 0.44, 0.45, 0.46, 0.48, 0.5, 0.52, 0.54, 0.55, 0.56, 0.58, 0.59, 0.6, 0.61, 0.62, 0.63, 0.65, 0.66, 0.68, 0.7, 0.71, 0.73, 0.75, 0.76, 0.77, 0.79, 0.8, 0.82, 0.84, 0.85, 0.87, 0.89, 0.9, 0.91, 0.93, 0.95, 0.96, 0.98, 0.99, 1 and any value in between; and / or, Li 1+y5 VO3, where 0 < y5 ≤ 3; and / or, Li 3+y6VO4, where 0 < y6 ≤ 3, for example, y5 and y6 can be 0.01, 0.03, 0.05, 0.08, 0.1, 0.13, 0.14, 0.16, 0.18, 0.2, 0.22, 0.24, 0.25, 0.26, 0.28, 0.3, 0.33, 0.34, 0.36, 0.38, 0.4, 0.42, 0.44, 0.45, 0.46, 0.48, 0.5, 0.52, 0.54, 0.55, 0.56, 0.58, 0.59, 0.6, 0.61, 0.62, 0.63, 0.65, 0.66, 0.68, 0.7, 0.71, 0.73, 0.75, 0.76, 0.77, 0.79, 0.8, 0.82, 0.84, 0.85, 0.87, 0.89, 0.9, 0.91, 0.93, 0.95, 0.96, 0.98, 0.99, 1, 1.01, 1.03, 1.05, 1.08, 1.1, 1.13, 1.14, 1.16, 1.18, 1.2, 1.22, 1.24, 1.25, 1.26, 1.28, 1.3, 1.33, 1.34, 1.36, 1.38, 1.4, 1.42, 1.44, 1.45, 1.46, 1.48, 1.5, 1.52, 1.54, 1.55, 1.56, 1.58, 1.59, 1.6, 1.61, 1.62, 1.63, 1.65, 1.66, 1.68, 1.7, 1.71, 1.73, 1.75, 1.76, 1.77, 1.79, 1.8, 1.82, 1.84, 1.85, 1.87, 1.89, 1.9, 1.91, 1.93, 1.95, 1.96, 1.98, 1.99, 2, 2.01, 2.03, 2.05, 2.08, 2.1, 2.13, 2.14, 2.16, 2.18, 2.2, 2.22, 2.24, 2.25, 2.26, 2.28, 2.3, 2.33, 2.34, 2.36, 2.38, 2.4, 2.42, 2.44, 2.45, 2.46, 2.48, 2.5, 2.52, 2.54, 2.55, 2.56, 2.58, 2.59, 2.6, 2.61, 2.62, 2.63, 2.65, 2.66, 2.68, 2.7, 2.71, 2.73, 2.75, 2.76, 2.77, 2.79, 2.8, 2.82, 2.84, 2.85, 2.87, 2.89, 2.9, 2.91, 2.93, 2.95, 2.96, 2.98, 2.99, 3 and any value in between; and / or, Li 3.1+y7 V 0.9 Ge 0.1O4, where 0 < y7 ≤ 2.7. For example, y7 can be 0.01, 0.03, 0.05, 0.08, 0.1, 0.13, 0.14, 0.16, 0.18, 0.2, 0.22, 0.24, 0.25, 0.26, 0.28, 0.3, 0.33, 0.34, 0.36, 0.38, 0.4, 0.42, 0.44, 0.45, 0.46, 0.48, 0.5, 0.52, 0.54, 0.55, 0.56, 0.58, 0.59, 0.6, 0.61, 0.62, 0.63, 0.65, 0.66, 0.68, 0.7, 0.71, 0.73, 0.75, 0.76, 0.77, 0.79, 0.8, 0.82, 0.84, 0.85, 0.87, 0.89, 0.9, 0.91, 0.93, 0.95, 0.96, 0.98, 0.99, 1, 1.01, 1.03, 1.05, 1.08, 1.1, 1.13, 1.14, 1.16, 1.18, 1.2, 1.22, 1.24, 1.25, 1.26, 1.28, 1.3, 1.33, 1.34, 1.36, 1.38, 1.4, 1.42, 1.44, 1.45, 1.46, 1.48, 1.5, 1.52, 1.54, 1.55, 1.56, 1.58, 1.59, 1.6, 1.61, 1.62, 1.63, 1.65, 1.66, 1.68, 1.7, 1.71, 1.73, 1.75, 1.76, 1.77, 1.79, 1.8, 1.82, 1.84, 1.85, 1.87, 1.89, 1.9, 1.91, 1.93, 1.95, 1.96, 1.98, 1.99, 2, 2.01, 2.03, 2.05, 2.08, 2.1, 2.13, 2.14, 2.16, 2.18, 2.2, 2.22, 2.24, 2.25, 2.26, 2.28, 2.3, 2.33, 2.34, 2.36, 2.38, 2.4, 2.42, 2.44, 2.45, 2.46, 2.48, 2.5, 2.52, 2.54, 2.55, 2.56, 2.58, 2.59, 2.6, 2.61, 2.62, 2.63, 2.65, 2.66, 2.68, 2.7 and any value in between.

[0033] In a second aspect of the present invention, a method for preparing a lithium-rich solid electrolyte is provided. The lithium-rich solid electrolyte is the lithium-rich solid electrolyte in the electrode sheet described in the first aspect of the present invention. The preparation method includes the following steps: mixing an organolithium compound with a solid electrolyte to obtain the lithium-rich solid electrolyte; the solid electrolyte contains a variable-valence metal element M. According to some preferred embodiments of the present invention, the organolithium compound contains an aromatic group.

[0034] Preferably, the variable valence metal element M is selected from Ti, V, Cr, Fe, Co, Ni, Nb, Mo, W, and Pt.

[0035] In the preparation method provided by this invention, all processes are carried out in an inert gas environment. In this invention, the inert gas can be argon, neon, etc. This invention does not have a particular limitation on the inert gas environment; in some preferred embodiments, the inert gas environment is provided by a glove box with an argon atmosphere.

[0036] According to the present invention, preferably, the organolithium compound is obtained by reacting metallic lithium with an aromatic hydrocarbon electron acceptor.

[0037] Preferably, the molar ratio of lithium metal to aromatic hydrocarbon electron acceptor is 0.5-3, for example, it can be 0.5, 0.6, 0.8, 1, 1.2, 1.5, 1.8, 2, 2.2, 2.5, 2.6, 2.8, 3 and any value in between, preferably 1-2.

[0038] According to the present invention, preferably, the total number of carbons in the aromatic hydrocarbon electron acceptor is 10-18, for example, 10, 11, 12, 13, 14, 15, 16, 17, or 18.

[0039] Preferably, the aromatic hydrocarbon electron acceptor is selected from at least one of 4-methoxybiphenyl, biphenyl, 4,4'-2-tert-butylbiphenyl, terphenyl, naphthalene, anthracene, and phenanthrene.

[0040] In this invention, the use of the above-mentioned preferred aromatic hydrocarbon electron acceptors is beneficial for accepting electrons from lithium atoms to form free radical anions, which have a better reducing ability than lithium metal; and can efficiently transfer electrons to the target reactants.

[0041] According to the present invention, the molar ratio of the solid electrolyte to the organic lithium compound is 1:(0.5-10), for example, it can be 1:0.5, 1:1, 1:2, 1:3, 1:4, 1:5, 1:6, 1:7, 1:8, 1:9, 1:10 and any value in between, preferably 1:(0.5-4).

[0042] In this invention, if the molar ratio of the solid electrolyte to the organic lithium compound is too high, the solid electrolyte will be over-lithiated, and excess lithium ions will accumulate on the surface of the solid electrolyte particles. When in contact with carbon dioxide and water, alkaline carbonates will be generated to coat the particle surface, thereby affecting the subsequent slurry process. If the molar ratio is too low, the variable valence metal in the solid electrolyte cannot be completely reduced, and the lithium ions are insufficient to be fully embedded in the solid electrolyte material.

[0043] According to the present invention, preferably, the mixing reaction comprises: mixing an organic lithium compound with a solid electrolyte under ultrasonic conditions for 2-6 hours and then allowing it to stand for 6-24 hours.

[0044] According to the present invention, preferably, the mixing reaction comprises: mixing the solid electrolyte with a first lithiation reagent containing an organolithium compound for 1-3 hours under ultrasonic conditions, allowing it to stand for 6-12 hours and then separating it to obtain a pre-lithiated solid electrolyte; then continuing to mix the pre-lithiated solid electrolyte with a second lithiation reagent containing an organolithium compound for 1-3 hours under ultrasonic conditions, and then allowing it to stand for 6-12 hours.

[0045] In this invention, there is no particular limitation on the separation method, as long as it achieves the technical objective of this invention. According to some preferred embodiments of this invention, the separation method is centrifugation.

[0046] In this invention, the purpose of ultrasound is to ensure that the solid electrolyte particles are fully dispersed in the organic lithium reagent; the purpose of settling is to prolong the reaction time to ensure that the solid electrolyte particles can fully react with the organic lithium reagent.

[0047] In this invention, the above-mentioned preferred mixed reaction conditions are conducive to the full reaction of the organic lithium reagent with the solid electrolyte. There is a concentration difference between the first lithium reagent and the second lithium reagent, so that after the solid electrolyte is replenished with lithium by the first lithium reagent, the second lithium reagent can still spontaneously replenish the solid electrolyte with lithium at a deeper level.

[0048] Preferably, the first and second lithiation reagents each contain a solvent.

[0049] In this invention, the degree of lithiation of the solid electrolyte is controlled by adjusting the molar ratio of the solid electrolyte to the organic lithium compound, gradually achieving full lithiation of the solid electrolyte and reaching a final lithium-rich solid electrolyte. Furthermore, by preparing lithiation reagents of different concentrations and applying them to the solid electrolyte according to a low-to-high concentration gradient, this concentration gradient of lithiation reagents ensures sufficient lithium replenishment of the solid electrolyte. Using Li... 1.3 Al 0.3 Ti 1.7 Taking (PO4)3(LATP) as an example, the XRD pattern is shown in Figure 1. When the molar ratio of solid electrolyte to organolithium compound is 1:0.5, the solid electrolyte is lithiated to Li. 1.7 Al 0.3 Ti 1.7 (PO4)3, when the molar ratio is 1:1, the solid electrolyte is lithium-lithiated to Li2Al. 0.3 Ti 1.7(PO4)3; As the molar ratio of LATP to organolithic compounds increases, the degree of lithiation of the LATP electrolyte varies, gradually transforming it into lithium-rich LATP (Li3Al) with a higher degree of lithiation. 0.3 Ti 1.7 (PO4)3).

[0050] Preferably, the solvent is an ester and / or an ether solvent, preferably selected from at least one of ethylene glycol dimethyl ether, cyclopentyl methyl ether, 1,3-dioxolane, tetrahydrofuran, γ-butyrolactone, and ethyl acetate.

[0051] Preferably, the molar concentrations of the organolithium compounds in the first and second lithiation reagents are M1 and M2, respectively.

[0052] Preferably, M1 is 0.05-1 mol / L; M2 is 0.1-4 mol / L.

[0053] Preferably, the molar concentrations of the organolithium compounds in the first and second lithiation reagents satisfy M2≥M1, and more preferably M2≥2M1.

[0054] In this invention, the molar concentration of the organic lithium compound in the first and second lithiation reagents being within the above-mentioned preferred range is beneficial because after the first lithiation reagent lightly replenishes the lithium in the solid electrolyte, the high lithium content in the second lithiation reagent can fully replenish the lithium in the solid electrolyte.

[0055] According to the present invention, preferably, the preparation method further includes separating, drying and washing the product obtained after the mixing reaction.

[0056] This invention does not impose particular limitations on the conditions for separation, drying, and washing, as long as they achieve the objectives of the invention. In some preferred embodiments of the invention, centrifugation is used to separate the products obtained after the mixing reaction. Drying is performed by allowing the mixture to stand in a glove box. Preferably, the products are washed using a solvent of the same type as that used in the mixing reaction.

[0057] A third aspect of the present invention provides a battery cell comprising the electrode sheet provided in the first aspect of the present invention.

[0058] A fourth aspect of the present invention provides a battery comprising the battery cell provided in the third aspect of the present invention.

[0059] The lithium-ion battery is assembled using the electrode containing lithium-rich solid electrolyte provided by this invention. On the one hand, the lithium-rich solid electrolyte contained therein can replenish irreversible lithium loss during the first charge and discharge process of the battery, thereby improving the cycle stability and rate performance of the lithium-ion battery. On the other hand, the lithium-rich solid electrolyte has a low irreversible delithiation voltage, is not prone to gas generation, and the delithiated solid electrolyte has excellent lithium-ion conduction, electrochemical stability, no by-products generated, and is safe and non-flammable. This is beneficial to the safety performance of the lithium-ion battery.

[0060] The present invention will be described in detail below through embodiments.

[0061] In this invention, the DCR test method is a hybrid pulse power characteristic test. First, the battery is charged with constant current and constant voltage to the upper limit cutoff voltage. After resting for a period of time, a 2C current pulse discharge is performed for 10 seconds. The voltage drop and discharge current at this time are recorded, and the internal resistance is calculated by Ohm's law.

[0062] In this invention, the battery capacity and cycle data are tested by the Blue Electric workstation.

[0063] Drug abbreviation and name: EC: Ethylene carbonate, analytical grade.

[0064] DMC: Dimethyl carbonate, analytical grade.

[0065] EMC: Ethyl methyl carbonate, analytical grade.

[0066] Example 1: Preparation of lithium replenishment solution: In an inert gas environment, 0.01 mol of dried biphenyl was added to 20 ml of anhydrous ethylene glycol dimethyl ether solvent and dissolved completely. Then, 0.005 mol of fresh lithium flakes was added to the solution prepared above to obtain a 0.005 mol low-concentration lithiation reaction reagent 1 containing organolithium compounds (concentration 0.25 mol / L). Another 0.015 mol high-concentration reaction reagent 2 containing organolithium compounds (concentration 0.75 mol / L) was prepared in the same way.

[0067] Lithium-ionized solid electrolyte: 0.01 mol of LTOP-1 (LiTiOPO4) powder with a D90 particle size of 50 nm (measured by laser particle size analyzer) was first added to reagent 1 of the above lithiation reaction. After thorough mixing and sonication at room temperature for 1 h, the mixture was centrifuged at 1000 rpm / min to obtain a dark brown viscous slurry. Then, a high concentration of lithiation reaction reagent 2 (molar ratio of LTOP to the total of reagent 1 and reagent 2 = 1:2) was added. The mixture was thoroughly mixed, sonicated for 1 h, and allowed to stand for 24 h.

[0068] To obtain a lithium-rich solid electrolyte: the turbid liquid after standing was thoroughly washed with ethylene glycol dimethyl ether solvent and centrifuged twice to obtain the lower precipitate. The precipitate was dried in a glove box to obtain lithium-rich LTOP-2. Further ICP testing was performed to determine the Li content in the lithiated solid electrolyte, confirming the chemical formula of the lithiated solid electrolyte LTOP-2 as Li2TiOPO4. A positive electrode containing lithium-rich LTOP-2: the main positive electrode material system is NCM811. During the positive electrode homogenization process, 3% (based on the total mass of the active layer) of the dried lithium-rich solid electrolyte Li2TiOPO4 was added for homogenization, coating, drying, and rolling. The positive electrode was then die-cut to obtain the positive electrode sheet.

[0069] Preparation of the negative electrode: The negative electrode system consists of 25wt% SiO + 75wt% Gr, which is homogenized, coated, dried, and rolled. After die-cutting, the negative electrode sheet is obtained.

[0070] The diaphragm uses a double-layer alumina diaphragm (1μmAl2O3+9μmPE+1μmAl2O3 diaphragm).

[0071] The electrolyte is EC + DMC + EMC (EC:DMC:EMC = 3:5:2, volume ratio) + 1M LiPF6.

[0072] The above-mentioned electrodes and separators were stacked, assembled, and electrolyte injected to obtain a pouch cell after formation. The obtained cells were then tested. The test results are shown in Table 1.

[0073] Example 2: Preparation of lithium replenishment solution: In an inert gas environment, 0.01 mol of dried biphenyl was added to 20 ml of anhydrous ethylene glycol dimethyl ether solvent and dissolved completely. Then, 0.01 mol of fresh lithium flakes was added to the solution prepared above to obtain 0.01 mol of reagent 1 (concentration of 0.5 mol / L) containing organolithium compounds for lithiation reaction. Another batch of lithiation reagent 2 with the same concentration was prepared in the same way.

[0074] Lithium-ionized solid electrolyte: 0.01 mol of LTOP-1 (LiTiOPO4) powder with a D90 particle size of 50 nm was added to reagent 1 of the above lithiation reaction. After thorough mixing and sonication at room temperature for 1 h, the mixture was centrifuged at 1000 rpm / min to obtain a dark brown viscous slurry. Then, reagent 2 of the lithiation reaction (the molar ratio of LTOP to the total of reagent 1 and reagent 2 = 1:2) was added to obtain a turbid liquid. The mixture was thoroughly mixed, sonicated for 1 h, and allowed to stand for 24 h.

[0075] To obtain the lithium-rich solid electrolyte: the turbid liquid after standing was thoroughly washed with ethylene glycol dimethyl ether solvent and centrifuged twice to obtain the lower precipitate. The precipitate was dried in a glove box to obtain lithium-rich LTOP-2. Further ICP testing was performed to determine the Li content in the lithiated solid electrolyte, confirming the chemical formula of the lithiated solid electrolyte LTOP-2 as Li. 1.7 TiOPO4; a lithium-rich solid electrolyte containing Li 1.7 TiOPO4 positive electrode sheet: The main positive electrode material system is NCM811, and 3% (based on the total mass of the active layer) of the above-mentioned dried lithium-rich solid electrolyte Li is added during the positive electrode homogenization process. 1.7 TiOPO4 is homogenized, coated, dried, and rolled. After die-cutting, the positive electrode sheet is obtained.

[0076] The parameters of the negative electrode, separator, and electrolyte are the same as in Example 1.

[0077] The above-mentioned electrodes and separators were stacked, assembled, and electrolyte injected to obtain a pouch cell after formation. The obtained cells were then tested. The test results are shown in Table 1.

[0078] Example 3: Preparation of lithium replenishment solution: In an inert gas environment, 0.01 mol of dried 4-methoxybiphenyl was added to 20 ml of anhydrous ethylene glycol dimethyl ether solvent and dissolved completely. Then, 0.005 mol of fresh lithium flakes was added to the solution prepared above to obtain a 0.005 mol low-concentration lithiation reaction reagent 1 containing organolithium compounds (concentration 0.25 mol / L). Another 0.015 mol high-concentration reaction reagent 2 containing organolithium compounds (concentration 0.75 mol / L) was prepared in the same way.

[0079] Lithium-based solid electrolyte: 0.01 mol of LATP-1 (Li₂O₃) with a particle size of 150 nm. 1.3 Al 0.3 Ti 1.7 (PO4)3) powder is first added to reagent 1 of the above lithiation reaction and mixed thoroughly. After sonication at room temperature for 1 hour, it is centrifuged at 1000 rpm / min to obtain a dark brown viscous slurry. Then, a high concentration of lithiation reaction reagent 2 (the molar ratio of LATP to the total of reagent 1 and reagent 2 is 1:2) is added to obtain a turbid liquid. The mixture is then thoroughly mixed, sonicated for 1 hour, and allowed to stand for 24 hours.

[0080] To obtain the lithium-rich solid electrolyte: the turbid liquid after standing was thoroughly washed with ethylene glycol dimethyl ether solvent and centrifuged twice to obtain the lower precipitate. The precipitate was dried in a glove box to obtain the lithium-rich LATP-2 solid electrolyte. The lithium-rich solid electrolyte was further tested by ICP to determine the Li content in the lithium-rich solid electrolyte, and the chemical formula of the lithium-rich solid electrolyte LATP-2 was determined to be Li3Al.0.3 Ti 1.7 The XRD pattern of (PO4)3; LATP is shown in Figure 1. Figure 1 shows that as the molar ratio of LATP to organolithium compounds increases, the degree of lithiation of the LATP electrolyte varies, gradually transforming it into lithium-rich LATP (Li3Al) with a higher degree of lithiation. 0.3 Ti 1.7 (PO4)3).

[0081] A positive electrode containing lithium-rich LATP-2: wherein the main positive electrode material system is NCM811, and 3% (based on the total mass of the active layer) of the above-mentioned dried lithium-rich solid electrolyte Li3Al is added during the positive electrode homogenization process. 0.3 Ti 1.7 The (PO4)3 is homogenized, coated, dried, and rolled. After die-cutting, the positive electrode sheet is obtained.

[0082] Preparation of the negative electrode: The negative electrode system consists of 25wt% SiO + 75wt% Gr, which is homogenized, coated, dried, and rolled. After die-cutting, the negative electrode sheet is obtained.

[0083] The diaphragm uses a double-layer alumina diaphragm (1μmAl2O3+9μmPE+1μmAl2O3 diaphragm).

[0084] The electrolyte is EC + DMC + EMC (EC:DMC:EMC = 3:5:2, volume ratio) + 1M LiPF6.

[0085] The above-mentioned electrodes and separators were stacked, assembled, and electrolyte injected to obtain a pouch cell after formation. The obtained cells were then tested. The test results are shown in Table 1.

[0086] Example 4: The preparation method of the lithium-rich solid electrolyte is the same as in Example 3, except that the LATP solid electrolyte used has a particle size of 1 micrometer; other parameters are the same as in Example 3; the configuration parameters of the positive electrode, the amount of solid electrolyte mixed in the positive electrode, the negative electrode, the separator, and the electrolyte are the same as in Example 2; the above electrodes and separator are stacked, assembled, injected with electrolyte, and formed to obtain a pouch battery. The obtained battery cell is then tested. The test results are shown in Table 1.

[0087] Example 5 uses the same method as Example 1, except that the order of adding lithiation reagents 1 and 2 is changed in the lithiation solid electrolyte step. Specifically, a high-concentration lithiation reagent is used first for lithiation of the solid electrolyte, followed by a low-concentration reagent. The lithiation solid electrolyte is then subjected to ICP testing to determine the Li content, thus confirming the chemical formula of the lithiated solid electrolyte LTOP-2 as Li. 1.8 TiOPO4; subsequent cell test results are shown in Table 1.

[0088] Example 6: Preparation of lithium replenishment solution: In an inert gas environment, 0.01 mol of dried phenanthrene was added to 20 ml of anhydrous ethylene glycol dimethyl ether solvent and dissolved completely. Then, 0.01 mol of fresh lithium flakes was added to the solution prepared above to obtain 0.01 mol of reagent 1 (concentration of 0.5 mol / L) containing organolithium compounds for the lithiation reaction. Another 0.02 mol of high-concentration reaction reagent 2 (concentration of 1 mol / L) containing organolithium compounds was prepared in the same way.

[0089] Lithium-based solid electrolyte: 0.01 mol of Li 3.1 V 0.9 Ge 0.1 O4 powder is first added to reagent 1 of the above-mentioned lithiation reaction. After thorough mixing and sonication at room temperature for 1 hour, it is centrifuged at 1000 rpm / min to obtain a viscous slurry. Then, high-concentration lithiation reaction reagent 2 (molar ratio of LVGO to the total of reagent 1 and reagent 2 = 1:3) is added to obtain a turbid liquid. After thorough mixing and sonication for 1 hour, it is allowed to stand for 24 hours.

[0090] To obtain the lithium-rich solid electrolyte: the turbid liquid after standing was thoroughly washed with ethylene glycol dimethyl ether solvent and centrifuged twice to obtain the lower precipitate. The precipitate was dried in a glove box to obtain the lithium-rich LVGO solid electrolyte. Further ICP testing was performed to determine the Li element content. The chemical formula of the lithium-rich solid electrolyte is Li. 5.8 V 0.9 Ge 0.1 O4; the particle size of lithium-rich LVGO is 400 nm.

[0091] A lithium-rich solid electrolyte Li 5.8 V 0.9 Ge 0.1 The positive electrode of O4: The main material system of the positive electrode is NCM811, and 0.1% of the above-mentioned dried lithium-rich solid electrolyte Li is added during the positive electrode homogenization process. 5.8 V 0.9 Ge 0.1 O4 is homogenized, coated, dried, and rolled. After die-cutting, the positive electrode sheet is obtained.

[0092] The parameters of the negative electrode, separator, and electrolyte are the same as in Example 1.

[0093] The above-mentioned electrodes and separators are stacked, assembled, and injected with electrolyte to form a soft-pack battery.

[0094] Example 7 uses the same method as Example 6, except that 3% of the above-mentioned lithium-rich solid electrolyte Li was added during the positive electrode homogenization process. 5.8 V 0.9 Ge 0.1 O4; other parameters remain unchanged.

[0095] Example 8: Preparation of lithium replenishment solution: In an inert gas environment, 0.01 mol of dried biphenyl was added to 20 ml of anhydrous ethylene glycol dimethyl ether solvent and dissolved completely. Then, 0.005 mol of fresh lithium flakes was added to the above solution to obtain 0.005 mol of reagent 1 (concentration of 0.25 mol / L) containing organolithium compounds for the lithiation reaction. Another 0.015 mol of high-concentration reaction reagent 2 (concentration of 0.75 mol / L) containing organolithium compounds was prepared in the same way.

[0096] Lithium-ionized solid electrolyte: 0.01 mol of LLTO-1 (Li₂O₃) with a D90 particle size of 250 nm. 0.32 La 0.56 TiO3 powder was first added to reagent 1 of the above lithiation reaction. After thorough mixing and sonication at room temperature for 1 hour, the mixture was centrifuged at 1000 rpm / min to obtain a viscous slurry. Then, a high concentration of lithiation reaction reagent 2 (the molar ratio of LLTO to the total of reagent 1 and reagent 2 = 1:2) was added to obtain a turbid liquid. The mixture was thoroughly mixed and sonicated for 1 hour and then allowed to stand for 24 hours.

[0097] To obtain the lithium-rich solid electrolyte: the turbid liquid after standing was thoroughly washed with ethylene glycol dimethyl ether solvent and centrifuged twice to obtain the lower precipitate. The precipitate was dried in a glove box to obtain the lithium-rich LLTO-2 solid electrolyte. Further ICP testing was performed to determine the Li element content. The chemical formula of the lithium-rich solid electrolyte is Li. 1.32 La 0.56 TiO3; a lithium-rich solid electrolyte containing Li 1.32 La 0.56 Preparation of TiO3 anode sheet: The anode system uses 25wt% SiO + 75wt% Gr, mixed with 3% (based on the total mass of the active layer) lithium-rich solid electrolyte Li. 1.32 La 0.56 TiO3 is homogenized, coated, dried, and rolled. After die-cutting, the negative electrode sheet is obtained.

[0098] The positive electrode material system is NCM811, which is homogenized, coated, dried, and rolled. After die-cutting, the positive electrode sheet is obtained.

[0099] The diaphragm uses a double-layer alumina diaphragm (1μmAl2O3+9μmPE+1μmAl2O3 diaphragm).

[0100] The electrolyte is EC + DMC + EMC (EC:DMC:EMC = 3:5:2, volume ratio) + 1M LiPF6.

[0101] The above-mentioned electrodes and separators were stacked, assembled, and electrolyte injected to obtain a pouch cell after formation. The obtained cells were then tested. The test results are shown in Table 1.

[0102] Comparative Example 1: Lithified solid electrolyte: 0.01 mol of LTOP-1 (LiTiOPO4) powder with a D90 particle size of 50 nm was mixed with lithium metal powder according to the stoichiometric ratio shown in Li2TiOPO4 (LTOP: lithium metal powder = 1:1 molar ratio) and heated at 250 °C for 2 h. After cooling, the lithified solid electrolyte powder LTOP-2 was obtained.

[0103] The lithium-rich LTOP-2 was further subjected to ICP testing to determine the Li content in the lithiated solid electrolyte, thus confirming the chemical formula of the lithiated solid electrolyte LTOP-2 as Li. 1.5 TiOPO4; a positive electrode containing lithium-rich LTOP-2: wherein the main positive electrode material system is NCM811, and 3% (based on the total mass of the active layer) of the above-mentioned dried lithium-rich solid electrolyte Li is added during the positive electrode homogenization process. 1.5 TiOPO4 is homogenized, coated, dried, and rolled. After die-cutting, the positive electrode sheet is obtained.

[0104] The parameters of the negative electrode, separator, and electrolyte are the same as in Example 1.

[0105] The above-mentioned electrodes and separators were stacked, assembled, and electrolyte injected to obtain a pouch cell after formation. The obtained cells were then tested. The test results are shown in Table 1.

[0106] Comparative Example 2: Positive electrode preparation: 3% LATP solid electrolyte and 2% lithium supplement Li2NiO2 (LNO) were added during the NCM811 positive electrode homogenization process to obtain the positive electrode. The negative electrode and separator were the same as those used in Example 1. The above-mentioned electrode and separator were stacked, assembled, and injected with electrolyte to obtain a pouch cell after formation. The obtained cells were then tested. The test results are shown in Table 1.

[0107] Comparative Example 3: Positive electrode preparation: 3% LATP was added during the NCM811 positive electrode homogenization process to obtain the positive electrode. The negative electrode and separator were the same as those used in Example 1. The above-mentioned electrode and separator were stacked, assembled, and injected with electrolyte to obtain a pouch cell after formation. The obtained cells were then tested. The test results are shown in Table 1.

[0108] Comparative Example 4: Positive electrode preparation: 2% lithium supplement Li2NiO2 was added during the NCM811 positive electrode homogenization process to obtain the positive electrode. The negative electrode and separator were the same as those used in Example 1. The above-mentioned electrode and separator were stacked, assembled, and injected with electrolyte to obtain a pouch cell after formation. The obtained cells were then tested. The test results are shown in Table 1.

[0109] Table 1 Cell Test Results

[0110] The cycle life in the table refers to the number of cycles during which the capacity decays to 80% of the theoretical specific capacity.

[0111] Examples 1-8 show that the lithium-ion battery assembled with the lithium-rich solid electrolyte of this application has a lower DCR (DC internal resistance), better cycle life, safer needle penetration performance, and better capacity retention; it achieves a balance between performance and safety compared to traditional lithium replenishment methods.

[0112] The preferred embodiments of the present invention have been described in detail above; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combinations of various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

Claims

1. A lithium-ion battery electrode, characterized in that, The electrode contains a lithium-rich solid electrolyte; the lithium-rich solid electrolyte contains a variable-valence metal element M, the variable-valence metal element M in the solid electrolyte has a valence state of +3 to +6, and the variable-valence metal element M in the lithium-rich solid electrolyte has a valence state of +2 to +5.

2. The electrode according to claim 1, wherein, The electrode comprises a current collector and an active layer composited on the surface of the current collector, the active layer comprising an active material and a lithium-rich solid electrolyte; preferably, the electrode is a positive electrode and / or a negative electrode; preferably, the active material comprises a positive electrode active material and / or a negative electrode active material; preferably, the lithium-rich solid electrolyte is prepared by chemical lithium supplementation from a solid electrolyte; preferably, the content of lithium-rich solid electrolyte in the electrode is 0.1-5% based on the total mass of the active layer, more preferably 1-3%; preferably, the positive electrode active material is selected from at least one of lithium cobalt oxide, nickel-cobalt-manganese ternary materials, lithium iron phosphate, and lithium manganese iron phosphate; preferably, the negative electrode active material is selected from at least one of graphite, silicon, silicon-carbon, and silicon-oxygen.

3. The electrode according to claim 1 or 2, wherein, The variable valence metal element M is selected from at least one of the variable valence metal elements of group IVB, group VB, group VIB, and group VIII, and preferably from at least one of Ti, V, Cr, Fe, Co, Ni, Nb, Mo, W, and Pt.

4. The electrode according to any one of claims 1-3, wherein, The solid electrolyte contains 9-25% molar percentage of the variable-valence metal element M; preferably, the solid electrolyte is selected from at least one of NASICON-type, perovskite, γ-Li3PO4-type, antifluorite-type, and xenotime-structured solid electrolytes, and more preferably from Li 1+x Al x Ti 2-x (PO4)3, where 0.3 ≤ x ≤ 0.5; Li 0.32 La 0.56 TiO3, LiTiOPO4, Li4TiO4, LiVO3, Li3VO4, Li 3.1 V 0.9 Ge 0.1 At least one of O4.

5. The electrode according to any one of claims 1-4, wherein, The particle size of the solid electrolyte is 50-500 nm; more preferably 50-250 nm.

6. The electrode according to any one of claims 1-5, wherein, The chemical composition of the lithium-rich solid electrolyte includes: Li 1+x+y1 Al x Ti 2-x (PO4)3, where 0.3 ≤ x ≤ 0.5 and 1.9 < 1 + x + y1 ≤ 3; and / or, Li 0.32+y2 La 0.56 TiO3, where 0.38 < y2 ≤ 1; and / or, Li 1+y3 TiOPO4, where 0 < y3 ≤ 1; and / or, Li 4+y4 TiO4, where 0 < y4 ≤ 1; and / or, Li 1+y5 VO3, where 0 < y5 ≤ 3; and / or, Li 3+y6 VO4, where 0 < y6 ≤ 3; and / or, Li 3.1+y7 V 0.9 Ge 0.1 O4, where 0 < y7 ≤ 2.

7.

7. The electrode according to any one of claims 1-6, wherein, The method for preparing the lithium-rich solid electrolyte includes: mixing and reacting an organic lithium compound with a solid electrolyte to obtain the lithium-rich solid electrolyte; the solid electrolyte contains a variable-valence metal element M.

8. The electrode according to claim 7, wherein, The organolithium compound contains aromatic groups; preferably, the organolithium compound is obtained by reacting lithium metal and an aromatic hydrocarbon electron acceptor; preferably, the molar ratio of lithium metal to aromatic hydrocarbon electron acceptor is 0.5-3.

9. The electrode according to claim 7 or 8, wherein, The total number of carbons in the aromatic hydrocarbon electron acceptor is 10-18; preferably, the aromatic hydrocarbon electron acceptor is selected from at least one of 4-methoxybiphenyl, biphenyl, 4,4'-2-tert-butylbiphenyl, terphenyl, naphthalene, anthracene, and phenanthrene.

10. The electrode according to any one of claims 7-9, wherein, The molar ratio of the solid electrolyte to the organic lithium compound is 1:(0.5-10).

11. The electrode according to any one of claims 7-10, wherein, The mixing reaction includes: mixing an organolithium compound with a solid electrolyte under ultrasonic conditions for 2-6 hours, followed by standing for 6-24 hours; preferably, the mixing reaction includes: mixing the solid electrolyte with a first lithiation reagent containing an organolithium compound under ultrasonic conditions for 1-3 hours, standing for 6-12 hours, and then separating to obtain a pre-lithiated solid electrolyte; then, continuing to mix the pre-lithiated solid electrolyte with a second lithiation reagent containing an organolithium compound under ultrasonic conditions for 1-3 hours, followed by standing for 6-12 hours; preferably, the first and second lithiation reagents each contain a solvent; preferably, the solvent... The solvent is an ester and / or ether solvent, preferably selected from at least one of ethylene glycol dimethyl ether, cyclopentyl methyl ether, 1,3-dioxolane, tetrahydrofuran, γ-butyrolactone, and ethyl acetate; preferably, the molar concentrations of the organolithium compound in the first and second lithiation reagents are M1 and M2, respectively; preferably, M1 is 0.05-1 mol / L; M2 is 0.1-4 mol / L; preferably, the molar concentrations of the organolithium compound in the first and second lithiation reagents satisfy M2≥M1; more preferably, the molar concentrations of the organolithium compound in the first and second lithiation reagents satisfy M2≥2M1.

12. A battery cell, characterized in that, The battery cell comprises the electrode as described in any one of claims 1-11.

13. A battery, characterized in that, The battery comprises the cell of claim 12.

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