Lithium-supplementing positive electrode sheet, preparation method therefor, and use thereof

Abstract

The present application provides a lithium-supplementing positive electrode sheet, a preparation method therefor, and a use thereof. The lithium-supplementing positive electrode plate comprises a current collector and a positive electrode active layer provided on the current collector, the positive electrode active layer comprising a positive electrode material, a first lithium-supplementing agent, and a second lithium-supplementing agent. In the present application, the first lithium-supplementing agent and the second lithium-supplementing agent are used in the positive electrode active layer for combination, and the content ratio of the two is controlled within a suitable range, so that the advantages of two lithium-supplementing agents can be exerted while avoiding the negative impact of a single lithium-supplementing agent during use of a battery, increasing the capacity of the battery while effectively inhibiting the gas generation phenomenon during a lithium-supplementing process.

Description

Lithium supplementing positive electrode sheet, and preparation method and application thereof

[0001] The present application claims priority to the Chinese patent application No. 202411353940.9, filed on September 26, 2024, and entitled "Lithium supplementing positive electrode sheet, and preparation method and application thereof", the content of which is incorporated herein by reference in its entirety. TECHNICAL FIELD

[0002] Embodiments of the present application relate to the technical field of lithium ion batteries, in particular to a lithium supplementing positive electrode sheet, and a preparation method and application thereof. BACKGROUND

[0003] Lithium supplementing technology is an effective means to improve the energy density of lithium ion batteries while improving the cycle life and energy storage performance of the batteries. Currently, common lithium supplementing technologies include negative electrode lithium supplementing, positive electrode lithium supplementing, electrolyte lithium supplementing, separator lithium supplementing, current collector lithium supplementing, and electrochemical lithium supplementing. Among them, the positive electrode lithium supplementing technology can directly add a positive electrode lithium supplementing agent to the positive electrode slurry, has lower requirements for the lithium supplementing process, does not require modification of the production environment and equipment, and is more suitable for existing lithium ion battery manufacturing processes.

[0004] The commonly used positive electrode lithium supplementing agent is a lithium-rich transition metal oxide. During the delithiation process, the oxidation of the transition metal leads to an increase in the valence state of the transition metal, and oxygen gas or oxygen radicals are also generated. The residual lithium supplementing agent residues with high oxidation states remaining in the positive electrode sheet increase the risk of side reactions when in contact with the electrolyte, thereby increasing the risk of gas generation during battery use, especially in high-temperature environments. In addition, these high-valence lithium supplementing agent residues can generate a large amount of flammable gas when triggered by heat abuse (such as needle puncture, collision, etc.), thereby increasing the risk of thermal runaway and increasing the safety risk during battery use. SUMMARY

[0005] In view of this, the present application provides a lithium supplementing positive electrode sheet, and a preparation method and application thereof. The lithium supplementing positive electrode sheet uses a first lithium supplementing agent and a second lithium supplementing agent in the positive electrode active layer, and the content ratio of the two is controlled within a suitable range. This can take advantage of both lithium supplementing agents while avoiding the negative effects of a single lithium supplementing agent during battery use, thereby improving battery capacity while effectively suppressing gas generation during the lithium supplementing process.

[0006] The first aspect of the present application provides a lithium supplementing positive electrode sheet, which comprises a current collector and a positive electrode active layer arranged on the current collector, wherein the positive electrode active layer comprises a positive electrode material, a first lithium supplementing agent and a second lithium supplementing agent; the volume change range of the first lithium supplementing agent before and after the first delithiation is greater than the volume change range of the second lithium supplementing agent before and after the first delithiation; the first charge gram capacity of the first lithium supplementing agent is greater than the first charge gram capacity of the second lithium supplementing agent; the first discharge gram capacity of the first lithium supplementing agent is less than the first discharge gram capacity of the second lithium supplementing agent; and the volume ratio of the first lithium supplementing agent to the second lithium supplementing agent in the lithium supplementing positive electrode sheet after the first delithiation is 1:(0.2-3).

[0007] In the embodiments of the present application, the volume ratio of the first lithium supplementing agent to the second lithium supplementing agent in the lithium supplementing positive electrode sheet after the first delithiation is 1:(0.3-3).

[0008] In the embodiments of the present application, the volume of the first lithium supplementing agent after the first delithiation is 40%-90% of the volume before the first delithiation, and the volume of the second lithium supplementing agent after the first delithiation is 60%-98% of the volume before the first delithiation.

[0009] In the embodiments of the present application, the porosity of the first lithium supplementing agent after the first delithiation is 5%-60%, and the porosity of the second lithium supplementing agent after the first delithiation is 1%-40%; the porosity of the second lithium supplementing agent after the first delithiation is less than the porosity of the first lithium supplementing agent after the first delithiation.

[0010] In the embodiments of the present application, the first charge gram capacity of the first lithium supplementing agent ranges from 400 mAh / g to 1200 mAh / g, and the first charge-discharge efficiency of the first lithium supplementing agent ranges from 1% to 14%; and / or, the first charge gram capacity of the second lithium supplementing agent ranges from 240 mAh / g to 550 mAh / g, and the first charge-discharge efficiency of the second lithium supplementing agent ranges from 15% to 45%.

[0011] In the embodiments of the present application, the first lithium supplementing agent comprises one or more of Li5FeO4, Li2O, Li6CoO4, Li5ReO6 and Li4CoO4; and / or, the second lithium supplementing agent comprises one or more of Li2NiO2, Li2CuO2, Li2RuO3, Li2MnO3, Li2MoO3 and Li 0.65 Ni 1.35 O2.

[0012] In the embodiments of the present application, the sum of the volumes of the first lithium supplementing agent and the second lithium supplementing agent in the lithium supplementing positive electrode sheet accounts for 0.1%-8% of the volume of the positive electrode active layer.

[0013] In the embodiments of the present application, the particle size D50 of the first lithium supplementing agent is 3-15 μm; and / or the particle size D50 of the second lithium supplementing agent is 4-23 μm.

[0014] In the embodiments of the present application, the positive electrode material comprises one or more of lithium iron manganese phosphate, lithium iron phosphate, lithium nickel manganese phosphate and ternary positive electrode material; the ternary positive electrode material comprises lithium nickel cobalt manganese phosphate and / or lithium nickel cobalt aluminum phosphate.

[0015] In the embodiments of the present application, the positive electrode active layer further comprises a conductive agent; the conductive agent comprises one or more of conductive graphite, carbon black, acetylene black, super-P, carbon nanotube, graphene, Ketjen black and VGCF.

[0016] In the embodiments of the present application, the positive electrode active layer further comprises a binder; the binder comprises one or more of polyvinylidene fluoride, polytetrafluoroethylene, polyimide, polyacrylate, lithium polyacrylate and sodium polyacrylate.

[0017] In the embodiments of the present application, the first charge capacity of the lithium-supplementing positive electrode sheet is 0.25-13% larger than that of a positive electrode sheet without the first lithium supplementing agent and the second lithium supplementing agent.

[0018] The second aspect of the present application further provides a preparation method of the lithium-supplementing positive electrode sheet provided in the first aspect of the present application, comprising:

[0019] mixing the positive electrode material, the first lithium supplementing agent and the second lithium supplementing agent to prepare a lithium-supplementing positive electrode active paste;

[0020] arranging the lithium-supplementing positive electrode active paste on a current collector to obtain a lithium-supplementing positive electrode sheet.

[0021] In the embodiments of the present application, the sum of the mass of the first lithium supplementing agent and the second lithium supplementing agent is 0.1-7.4% of the mass of the positive electrode material.

[0022] In the embodiments of the present application, the mass ratio of the first lithium supplementing agent to the second lithium supplementing agent is (0.1-10):1.

[0023] The third aspect of the present application provides a lithium ion battery, comprising a positive electrode sheet, a negative electrode sheet, and a separator and an electrolyte between the positive electrode sheet and the negative electrode sheet, wherein the positive electrode sheet comprises a lithium-supplementing positive electrode sheet provided in the first aspect of the present application or prepared by the preparation method provided in the second aspect of the present application.

[0024] The fourth aspect of the present application provides an electric device comprising the lithium ion battery provided in the third aspect of the present application. BRIEF DESCRIPTION OF DRAWINGS

[0025] FIG. 1 is a flowchart of a preparation method of a lithium-supplemented positive electrode sheet according to an embodiment of the present application;

[0026] FIG. 2 is a structural schematic diagram of a lithium ion battery according to an embodiment of the present application.

[0027] FIG. 1 is a flowchart of a preparation method of a lithium-supplemented positive electrode sheet according to an embodiment of the present application; DETAILED DESCRIPTION

[0028] The present application will be further described in conjunction with preferred embodiments. However, the scope of protection of the present application is not limited to the following specific embodiments.

[0029] In the present application, all the professional terms have the same meanings as generally understood by those skilled in the art. The professional terms used herein are only for the purpose of describing the specific embodiments and are not intended to limit the scope of protection of the present application.

[0030] Lithium supplement technology is an effective means to improve the energy density of lithium ion batteries while improving the cycle life and energy storage performance of the batteries. Currently, common lithium supplement technologies include negative electrode lithium supplement, positive electrode lithium supplement, electrolyte lithium supplement, separator lithium supplement, current collector lithium supplement, and electrochemical lithium supplement. Among them, the positive electrode lithium supplement technology can directly add a positive electrode lithium supplement agent to the positive electrode slurry during the homogenization process, has lower requirements for the lithium supplement process, does not require modification of the production environment and equipment, and is more suitable for existing lithium ion battery manufacturing processes.

[0031] The commonly used positive electrode lithium supplement agent is a lithium-rich transition metal oxide. During the delithiation process, the oxidation of transition metals leads to an increase in the oxidation state of transition metals, and oxygen or oxygen radicals are also released. The residual lithium supplement agent residues in the positive electrode sheet, which are in a high oxidation state, increase the risk of side reactions when in contact with the electrolyte, thereby increasing the risk of gas production during battery use, especially in high-temperature environments. In addition, these high-valence lithium supplement agent residues will produce a large amount of flammable gas when triggered by heat abuse (such as needle puncture, collision, etc.), thereby increasing the risk of thermal runaway and increasing the safety risk during battery use.

[0032] To solve the above problems, the present application provides a lithium-supplemented positive electrode sheet, a preparation method and application thereof. The lithium-supplemented positive electrode sheet uses a first lithium supplement agent and a second lithium supplement agent in the positive electrode active layer, and the content ratio of the two is controlled within a suitable range. This can take advantage of both lithium supplement agents while avoiding the negative effects of a single lithium supplement agent during battery use, thereby improving battery capacity while effectively suppressing gas production during the lithium supplement process.

[0033] The application provides a lithium supplementing positive electrode sheet, which comprises a current collector and a positive electrode active layer arranged on the current collector, and the positive electrode active layer comprises a positive electrode material, a first lithium supplementing agent and a second lithium supplementing agent. In the embodiment of the application, the volume change range of the first lithium supplementing agent before and after the first time of lithium extraction is greater than the volume change range of the second lithium supplementing agent before and after the first time of lithium extraction; and the first charge gram capacity of the first lithium supplementing agent is greater than the first charge gram capacity of the second lithium supplementing agent. In the embodiment of the application, the volume change range refers to the ratio of the difference between the volume of the first lithium supplementing agent and the second lithium supplementing agent before the first time of lithium extraction and the volume after the first time of lithium extraction to the volume before the first time of lithium extraction. After the first charge and lithium extraction, at least part of the lithium-rich first lithium supplementing agent and the second lithium supplementing agent become lithium-poor metal oxide residues after lithium extraction, so that the first lithium supplementing agent and the second lithium supplementing agent after the first time of lithium extraction collapse and the volume decreases. The first lithium supplementing agent has a greater first charge gram capacity than the second lithium supplementing agent, so the first lithium supplementing agent serves as the main lithium supplementing active substance in the positive electrode active layer and contributes greatly to the improvement of the battery capacity. Because the first lithium supplementing agent releases or precipitates oxygen and oxygen radicals during lithium extraction, the first lithium supplementing agent has a greater volume change before and after the first time of lithium extraction than the second lithium supplementing agent. Therefore, by adding the second lithium supplementing agent with a smaller volume change range before and after the first time of lithium extraction in the positive electrode active layer, the problem of gas production during the lithium extraction of the first lithium supplementing agent can be effectively alleviated, thereby improving the safety performance of the battery. In the embodiment of the application, the volume ratio of the first lithium supplementing agent to the second lithium supplementing agent in the lithium supplementing positive electrode sheet after the first time of lithium extraction is 1:(0.2-3). In some specific embodiments, the volume ratio of the first lithium supplementing agent to the second lithium supplementing agent in the lithium supplementing positive electrode sheet may, for example, be 1:0.2, 1:0.3, 1:0.4, 1:0.5, 1:0.6, 1:0.7, 1:0.8, 1:0.9, 1:1, 1:1.5, 1:2, 1:2.5, 1:3. By controlling the volume ratio of the first lithium supplementing agent to the second lithium supplementing agent in the lithium supplementing positive electrode sheet within a suitable range, the content ratio of the first lithium supplementing agent to the second lithium supplementing agent is controlled, the synergistic lithium supplementing effect of the two is exerted as much as possible, the lithium supplementing positive electrode sheet has good lithium supplementing effect, and at the same time, has high safety, thereby increasing the energy density, cycle life and safety performance of the battery.

[0034] In the present application, the first charge capacity of the first lithium supplement agent refers to the first lithium supplement agent being used as a battery positive electrode material to make a button cell, and then charging to 4.3V under the condition of 0.1C to obtain the first charge capacity of the first lithium supplement agent; the first discharge capacity of the first lithium supplement agent refers to the first lithium supplement agent being used as a battery positive electrode material to make a button cell, and then discharging to 2.5V under the condition of 0.1C to obtain the first discharge capacity of the first lithium supplement agent; the first charge-discharge efficiency is the ratio of the first discharge capacity to the first charge capacity. In the present application, the second charge capacity of the second lithium supplement agent refers to the second lithium supplement agent being used as a battery positive electrode material to make a button cell, and then charging to 4.3V under the condition of 0.1C to obtain the second charge capacity of the second lithium supplement agent; the second discharge capacity of the second lithium supplement agent refers to the second lithium supplement agent being used as a battery positive electrode material to make a button cell, and then discharging to 2.5V under the condition of 0.1C to obtain the second discharge capacity of the second lithium supplement agent; the second charge-discharge efficiency is the ratio of the second discharge capacity to the second charge capacity.

[0035] In some embodiments of the present application, the volume ratio of the first lithium supplement agent to the second lithium supplement agent in the lithium-supplemented positive electrode sheet after the first delithiation is 1:(0.3-3). Controlling the volume ratio of the first lithium supplement agent to the second lithium supplement agent within the above range can further limit the content of the first lithium supplement agent to be greater than or equal to the content of the second lithium supplement agent in the lithium-supplemented positive electrode sheet, and further optimize the synergistic lithium supplement effect of the first lithium supplement agent and the second lithium supplement agent, improve the lithium supplement efficiency of the first lithium supplement agent and the second lithium supplement agent, and as much as possible improve the battery energy density while further prolonging the cycle life of the battery.

[0036] In the embodiments of the present application, the volume of the first lithium supplement agent after the first delithiation is 40% to 90% of the volume before the first delithiation, and the volume of the second lithium supplement agent after the first delithiation is 60% to 98% of the volume before the first delithiation. After the first delithiation, the first lithium supplement agent and the second lithium supplement agent become lithium-rich first lithium supplement agent and second lithium supplement agent after delithiation, and the lithium-rich first lithium supplement agent and second lithium supplement agent become lithium-poor metal oxide residues after delithiation, so that the first lithium supplement agent and the second lithium supplement agent after the first delithiation collapse and change in volume. In the first lithium supplement agent, oxygen is released or oxygen radicals are precipitated during the delithiation process, and the volume changes greatly before and after the first delithiation. In the second lithium supplement agent, the valence of the metal element changes during the delithiation process, which can ensure that the oxygen element and the metal element in the second lithium supplement agent are tightly combined, so that the second lithium supplement agent does not release oxygen during the delithiation process. Compared with the first lithium supplement agent, the volume changes less before and after the first delithiation. By controlling the volume change range of the first lithium supplement agent and the second lithium supplement agent in the appropriate range, the present application can ensure the contribution of the lithium supplement agent to the capacity of the electrode sheet while further reducing the gas production caused by the release of oxygen from the first lithium supplement agent and the side reactions caused by the precipitation of oxygen radicals with the electrolyte. In some specific embodiments of the present application, the volume of the first lithium supplement agent after the first delithiation may, for example, be 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90% of the volume before the first delithiation. The volume of the second lithium supplement agent after the first delithiation may, for example, be 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, 98% of the volume before the first delithiation.

[0037] In the embodiments of the present application, the porosity of the first lithium supplement agent after the first delithiation is 5%-60%, and the porosity of the second lithium supplement agent after the first delithiation is 1%-40%; and the porosity of the second lithium supplement agent is less than the porosity of the first lithium supplement agent. The positive active layer of the lithium supplement positive electrode sheet provided in the present application has the first lithium supplement agent and the second lithium supplement agent, and the structure of the first lithium supplement agent and the second lithium supplement agent collapses after delithiation, and the volume decreases, and at the same time, cracks, gaps and other defects appear in the interior of the particles, thereby changing the porosity of the first lithium supplement agent and the second lithium supplement agent after the first delithiation. In the present application, the porosity of the second lithium supplement agent after the first delithiation is controlled to be less than the porosity of the first lithium supplement agent after the first delithiation, thereby further controlling the volume change of the first lithium supplement agent and the second lithium supplement agent before and after the first delithiation, so that the volume change of the second lithium supplement agent after the first delithiation is smaller than that of the first lithium supplement agent, the cracks in the interior of the second lithium supplement agent particles are fewer, and the corresponding porosity is also smaller, thereby further improving the synergistic effect of the first lithium supplement agent and the second lithium supplement agent, and improving the safety performance and cycle life of the lithium supplement positive electrode sheet. In some specific embodiments of the present application, the porosity of the first lithium supplement agent after the first delithiation may be, for example, 5%, 6%, 7%, 8%, 9%, 10%, 12%, 14%, 15%, 16%, 18%, 20%, 30%, 40%, 50%, 60%; and the porosity of the second lithium supplement agent after the first delithiation may be, for example, 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 15%, 20%, 30%, 40%.

[0038] In the embodiments of the present application, the first lithium supplement agent has a first charge gram capacity of 400 mAh / g-1200 mAh / g, and the first lithium supplement agent has a first charge-discharge efficiency of 1%-14%. In some specific embodiments, the first charge gram capacity of the first lithium supplement agent may be, for example, 400 mAh / g, 500 mAh / g, 600 mAh / g, 700 mAh / g, 800 mAh / g, 900 mAh / g, 1000 mAh / g, 1100 mAh / g, 1200 mAh / g, and the first charge-discharge efficiency of the first lithium supplement agent may be, for example, 1%, 2%, 3%, 4%, 5%, 6%, 8%, 10%, 12%, 14%. In the embodiments of the present application, the lithium content of the first lithium supplement agent after the first delithiation accounts for 70%-95% of the total lithium content of the first lithium supplement agent. In some specific embodiments, the lithium content of the first lithium supplement agent after the first delithiation may account for, for example, 70%, 75%, 80%, 85%, 90%, 95% of the total lithium content of the first lithium supplement agent. By controlling the related electrochemical parameters of the first lithium supplement agent within the above range, the lithium supplement efficiency of the first lithium supplement agent during the first charging can be further improved.

[0039] In the embodiments of the present application, the first charge specific capacity of the second lithium supplement agent is 240 mAh / g-550 mAh / g, and the first charge-discharge efficiency of the second lithium supplement agent is 15%-45%. In some specific embodiments, the first charge specific capacity of the second lithium supplement agent may, for example, be 240 mAh / g, 250 mAh / g, 280 mAh / g, 300 mAh / g, 350 mAh / g, 400 mAh / g, 450 mAh / g, 500 mAh / g, 550 mAh / g, and the first charge-discharge efficiency of the second lithium supplement agent may, for example, be 15%, 20%, 25%, 30%, 35%, 40%, 45%. In the embodiments of the present application, the lithium stripping amount of the second lithium supplement agent during the first lithium stripping is 55%-88% of the total lithium content of the second lithium supplement agent. In some specific embodiments, the lithium stripping amount of the second lithium supplement agent during the first lithium stripping may, for example, be 55%, 60%, 65%, 70%, 75%, 80%, 85%, 88% of the total lithium content of the second lithium supplement agent. By controlling the relevant electrochemical parameters of the second lithium supplement agent within the above range, the present application can further improve the lithium supplement efficiency of the second lithium supplement agent during the battery cycle process. In the present application, the first charge-discharge efficiency is the ratio of the first discharge specific capacity to the first charge specific capacity.

[0040] In the embodiments of the present application, the first charge specific capacity of the first lithium supplement agent is greater than the first charge specific capacity of the second lithium supplement agent, and the first charge-discharge efficiency of the second lithium supplement agent is greater than the first charge-discharge efficiency of the first lithium supplement agent. By controlling the first charge specific capacity and the first charge-discharge efficiency of the first lithium supplement agent and the second lithium supplement agent within the above range, the present application can further exert the capacity improvement effect of the first lithium supplement agent on the battery, and on the other hand, can further exert the advantage of the large reversible specific capacity of the second lithium supplement agent, so that the second lithium supplement agent continuously releases active lithium into the battery system during the repeated charge-discharge process of the battery, and realizes continuous lithium supplement during the battery cycle process.

[0041] In the embodiments of the present application, the first lithium supplement agent includes one or more of Li5FeO4, Li2O, Li6CoO4, Li5ReO6, and Li4CoO4. By selecting the above metal oxides with high oxygen content as the first lithium supplement agent, the present application can effectively exert the lithium supplement effect thereof during the first charging. In the embodiments of the present application, the second lithium supplement agent includes Li2NiO2, Li2CuO2, Li2RuO3, Li2MnO3, Li2MoO3, and Li 0.65 Ni 1.35one or more of O2. By selecting the above metal oxides as the second lithium supplement, these metal oxides will not cause oxygen evolution during charging and discharging, thereby making up for the defects of the first lithium supplement in safety performance. In addition, the residues of these second lithium supplements after the first delithiation are mostly of layered structure, which makes them have a higher reversible specific capacity, and active lithium is continuously released to the battery system during the battery cycle. By specially selecting and matching the first lithium supplement and the second lithium supplement, the obtained lithium-supplemented positive electrode sheet has good lithium supplement effect during the first charging and subsequent cycles.

[0042] In the embodiments of the present application, the sum of the volume of the first lithium supplement and the second lithium supplement in the lithium-supplemented positive electrode sheet accounts for 0.1%-8% of the volume of the positive active layer. In some specific embodiments, the sum of the volume of the first lithium supplement and the second lithium supplement accounts for 0.1%, 0.2%, 0.3%, 0.5%, 0.6%, 0.8%, 1%, 2%, 3%, 4%, 5%, 6%, 7%, or 8% of the volume of the positive active layer. By controlling the total amount of the first lithium supplement and the second lithium supplement in the positive active layer within a suitable range, the lithium-supplemented positive electrode sheet has good lithium supplement effect and energy density, thereby improving the capacity and cycle life of the battery. In addition, it can also effectively improve the utilization rate of the lithium supplement, avoid the waste of the lithium supplement or the demand for more negative electrode materials, effectively reduce the cost of the battery, and improve the energy density of the battery.

[0043] In the embodiments of the present application, the particle size D50 of the first lithium supplementing agent is 3-15 μm, and the particle size D50 of the second lithium supplementing agent is 4-23 μm. In some specific embodiments of the present application, the particle size D50 of the first lithium supplementing agent may, for example, be 3 μm, 4 μm, 5 μm, 6 μm, 7 μm, 8 μm, 9 μm, 10 μm, 11 μm, 12 μm, 13 μm, 14 μm, 15 μm, and the particle size D50 of the second lithium supplementing agent may, for example, be 4 μm, 5 μm, 6 μm, 8 μm, 10 μm, 12 μm, 14 μm, 15 μm, 16 μm, 18 μm, 20 μm, 22 μm, 23 μm. In the present application, the particle size D50 is specifically Dv50, that is, the particle size corresponding to the cumulative particle size distribution percentage of 50% of the measured sample, and the physical meaning is that the particles with a particle size greater than it account for 50%, and the particles with a particle size less than it also account for 50%. In the embodiments of the present application, the particle size D50 of the first lithium supplementing agent and the second lithium supplementing agent can be measured and calculated by using SEM (Scanning Electron Microscope) combined with EDS (Energy Dispersive Spectrometer), and can also be measured by using FIB-SEM (Focused Ion Beam-Scanning Electron Microscope). In the embodiments of the present application, the particle size D50 of the first lithium supplementing agent and the second lithium supplementing agent includes the particle size before the first time of lithium extraction, and also includes the particle size after the first time of lithium extraction, that is, the particle size of the first lithium supplementing agent and the second lithium supplementing agent before and after the first time of lithium extraction is within the above range. By controlling the particle size of the first lithium supplementing agent and the second lithium supplementing agent within the above range, on the one hand, the problem of excessive specific surface area of the lithium supplementing agent leading to side reactions with the electrolyte can be avoided, and on the other hand, the problem of large inert particles formed after lithium extraction hindering the transmission of lithium ions in the pole piece can be avoided, thereby further improving the safety performance and lithium ion transmission capacity of the lithium supplementing positive pole piece.

[0044] In the embodiments of the present application, the positive electrode material includes one or more of lithium iron manganese phosphate, lithium iron phosphate, lithium nickel manganese phosphate, and ternary positive electrode material, wherein the ternary positive electrode material includes lithium nickel cobalt manganese phosphate and / or lithium nickel cobalt aluminum phosphate. The first lithium supplementing agent and the second lithium supplementing agent in the lithium supplementing positive pole piece provided by the present application are not specially limited to the system of lithium ion batteries, and are suitable for most common lithium ion battery systems.

[0045] In the embodiments of the present application, the positive active layer further comprises a conductive agent, and the conductive agent comprises one or more of conductive graphite, carbon black, acetylene black, super-P, carbon nanotubes, graphene, Ketjen black and VGCF. By selecting a suitable conductive agent and a binder, the conductivity of the lithium supplementing positive electrode sheet can be further increased. In the embodiments of the present application, the positive active layer further comprises a binder, and the binder comprises one or more of polyvinylidene fluoride, polytetrafluoroethylene, polyimide, polyacrylate, lithium polyacrylate and sodium polyacrylate. By selecting a suitable binder, the binding force between the positive active layer and the current collector of the lithium supplementing positive electrode sheet and the binding force between the components in the positive active layer can be further increased.

[0046] In the embodiments of the present application, the first charge capacity of the lithium supplementing positive electrode sheet is 0.25%-13% larger than that of the positive electrode sheet without the first lithium supplementing agent and the second lithium supplementing agent. In the present application, the positive electrode sheet without the first lithium supplementing agent and the second lithium supplementing agent refers to the positive electrode sheet with the same composition and content of all components as the lithium supplementing positive electrode sheet, except that the first lithium supplementing agent and the second lithium supplementing agent are not added. In some specific embodiments, the first charge capacity of the lithium supplementing positive electrode sheet is 0.25%, 0.5%, 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12% or 13% larger than that of the positive electrode sheet without the first lithium supplementing agent and the second lithium supplementing agent. The lithium supplementing positive electrode sheet provided in the present application can effectively improve the capacity of the battery while ensuring the safety performance of the battery by using the first lithium supplementing agent and the second lithium supplementing agent. The active lithium released by the first lithium supplementing agent and the second lithium supplementing agent partly supplements the active lithium consumed in the SEI film formation process and partly supplements the reversible lithium lost in the lithium intercalation sites of the positive electrode sheet, so that the capacity of the battery after the first lithium supplementing agent and the second lithium supplementing agent supplement lithium has a certain degree of improvement. In the present application, the first charge capacity of the lithium supplementing positive electrode sheet is the sum of the three charge capacities obtained by charging the lithium supplementing positive electrode sheet at 0.05C for 2h, then charging to 3.8V at 0.2C, and then charging to 4.3V at 0.03C, respectively.

[0047] In the embodiments of the present application, the direct current discharge impedance of the lithium supplementing positive electrode sheet at room temperature is 1%-30% lower than that of the positive electrode sheet without the first lithium supplementing agent and the second lithium supplementing agent; and the direct current discharge impedance of the lithium supplementing positive electrode sheet at -10°C is 2%-40% lower than that of the positive electrode sheet without the first lithium supplementing agent and the second lithium supplementing agent. The lithium supplementing positive electrode sheet provided in the present application can effectively reduce the impedance of the battery by using the first lithium supplementing agent and the second lithium supplementing agent.

[0048] The lithium supplement positive electrode sheet provided by the application improves the capacity, safety performance and cycle life of the battery by using the first lithium supplement agent which contributes more to the capacity of the electrode sheet and the second lithium supplement agent which has a smaller volume change before and after the first delithiation to compound and control the content of the two within a suitable range.

[0049] The application also provides a preparation method of the lithium supplement positive electrode sheet provided above, and FIG. 1 is a flow chart of the preparation method, which comprises the following steps:

[0050] S101. mixing the positive electrode material, the first lithium supplement agent and the second lithium supplement agent to prepare a lithium supplement positive electrode active paste;

[0051] S102. arranging the lithium supplement positive electrode active paste on a current collector to obtain a lithium supplement positive electrode sheet.

[0052] In step S101, the sum of the mass of the first lithium supplement agent and the second lithium supplement agent is 0.1%-7.4% of the mass of the positive electrode material. In some specific embodiments, the sum of the mass of the first lithium supplement agent and the second lithium supplement agent may, for example, be 0.1%, 0.5%, 1%, 2%, 3%, 4%, 5%, 6%, 7%, 7.4% of the mass of the positive electrode material. By controlling the sum of the mass of the first lithium supplement agent and the second lithium supplement agent within a suitable range, the application can ensure that the positive electrode material provides sufficient energy density for the lithium supplement positive electrode sheet, exert the lithium supplement effect of the lithium supplement agent, and further improve the capacity and cycle life of the battery.

[0053] In the embodiments of the application, the mass ratio of the first lithium supplement agent to the second lithium supplement agent is (0.1-10):1. In some specific embodiments, the mass ratio of the first lithium supplement agent to the second lithium supplement agent may, for example, be 0.1:1, 0.5:1, 1:1, 2:1, 3:1, 4:1, 5:1, 6:1, 7:1, 8:1, 9:1, 10:1. In some embodiments, the mass ratio of the first lithium supplement agent to the second lithium supplement agent is (1-10):1.

[0054] In some embodiments of the application, the lithium supplement positive electrode active paste in step S101 further comprises a conductive agent and a binder. In the embodiments of the application, the conductive agent may be any conductive agent known in the art, for example, one or more of conductive graphite, carbon black, acetylene black, super-P, carbon nanotube, graphene, ketchen black and VGCF; and the binder may be any binder known in the art, for example, one or more of polyvinylidene fluoride, polytetrafluoroethylene, polyimide, polyacrylate, lithium polyacrylate and sodium polyacrylate.

[0055] In the embodiments of the present application, the sum of the mass of the positive electrode material, the first lithium supplementing agent and the second lithium supplementing agent accounts for 92.2% to 98.3% of the total mass of the lithium-supplemented positive electrode active paste; the mass of the conductive agent accounts for 0.5% to 3.8% of the total mass of the lithium-supplemented positive electrode active paste; the mass of the binder accounts for 1.2% to 4% of the total mass of the lithium-supplemented positive electrode active paste; wherein the total mass of the positive electrode active paste refers to the total mass of the paste after removing the solvent.

[0056] The preparation method provided by the present application has simple process, shorter flow and lower preparation cost, and is conducive to large-scale industrial production.

[0057] As shown in FIG. 2, the present application also provides a lithium ion battery 100, which comprises a positive electrode sheet 101, a negative electrode sheet 102, and an electrolyte 103 and a separator 104 located between the positive electrode sheet 101 and the negative electrode sheet 102, wherein the positive electrode sheet 101 comprises the lithium-supplemented positive electrode sheet provided in the foregoing or prepared by the preparation method provided in the foregoing. In the embodiments of the present application, the negative electrode sheet 102 comprises a negative electrode current collector and a negative electrode active layer arranged on the negative electrode current collector. The negative electrode active material in the negative electrode material layer can be any negative electrode active material commonly known in the art for lithium ion batteries. In the embodiments of the present application, the negative electrode active material in the negative electrode material layer can be any negative electrode active material commonly known in the art for lithium ion batteries. Exemplarily, the negative electrode active material can be selected from one or more of carbon-based negative electrode active materials, silicon-based negative electrode active materials, tin-based negative electrode active materials and lithium metal negative electrode active materials. The carbon-based negative electrode includes but is not limited to natural graphite, artificial graphite, hard carbon, soft carbon and graphene; the silicon-based negative electrode includes but is not limited to silicon, silicon-carbon and silicon-oxygen; and the tin-based negative electrode includes but is not limited to tin, tin-carbon, tin-oxygen and tin metal compounds.

[0058] The present application also provides an electric device comprising the lithium ion battery described in the foregoing. The electric device can be, for example, an electric vehicle, a mobile phone, a tablet computer, a notebook computer, a wearable device (watch, bracelet), a digital camera, etc.

[0059] The present application will be further described in the following embodiments:

[0060] Embodiment 1

[0061] 3g of the binder polyvinylidene fluoride was weighed and dissolved into 60g of the solvent N-methyl pyrrolidone, and then 3g of the conductive agent carbon black was added, and after mixing and stirring, a conductive glue solution was obtained;

[0062] 100g of the positive electrode material lithium iron phosphate was weighed and added into the conductive glue solution to prepare a positive electrode active paste;

[0063] 1 g of first lithium supplement Li5FeO4 with a particle size D50 of 6 μm and 1 g of second lithium supplement Li2NiO2 with a particle size D50 of 12 μm are added to the positive active paste to prepare a lithium-supplemented positive active paste;

[0064] The first lithium supplement has a first discharge gram capacity of 713 mAh / g, a first charge gram capacity of 43 mAh / g, and a first charge-discharge efficiency of 6.03%; and the second lithium supplement has a first discharge gram capacity of 413 mAh / g, a first charge gram capacity of 124 mAh / g, and a first charge-discharge efficiency of 30.02%.

[0065] The lithium-supplemented positive active paste is coated on an aluminum foil, and a lithium-supplemented positive electrode sheet is obtained after baking and rolling.

[0066] Example 2

[0067] The difference from Example 1 is that the mass of the first lithium supplement is 1.5 g and the mass of the second lithium supplement is 0.5 g.

[0068] Example 3

[0069] The difference from Example 1 is that the mass of the first lithium supplement is 0.5 g and the mass of the second lithium supplement is 1.5 g.

[0070] Example 4

[0071] The difference from Example 1 is that the mass of the first lithium supplement is 1.2 g and the mass of the second lithium supplement is 0.8 g.

[0072] Example 5

[0073] The difference from Example 1 is that the first lithium supplement is Li6CoO4 with a particle size D50 of 10 μm, the first lithium supplement has a first discharge gram capacity of 977 mAh / g, a first charge gram capacity of 103 mAh / g, and a first charge-discharge efficiency of 10.54%; and after the first lithium-supplemented positive electrode sheet is subjected to the first delithiation, the volume ratio of the first lithium supplement to the second lithium supplement is 1:0.9.

[0074] Example 6

[0075] The difference from Example 1 is that the second lithium supplement is Li2CuO2 with a particle size D50 of 10 μm, the second lithium supplement has a first discharge gram capacity of 406 mAh / g, a first charge gram capacity of 123 mAh / g, and a first charge-discharge efficiency of 30.29%; and after the first lithium-supplemented positive electrode sheet is subjected to the first delithiation, the volume ratio of the first lithium supplement to the second lithium supplement is 1:1.1.

[0076] Example 7

[0077] The difference from Example 6 is that the mass of the first lithium supplement agent is 2 g, and the mass of the second lithium supplement agent is 2 g; after the first lithium supplement agent and the second lithium supplement agent are subjected to the first delithiation, the volume ratio of the first lithium supplement agent to the second lithium supplement agent is 1:0.9.

[0078] Example 8

[0079] The difference from Example 1 is that the particle size D50 of the first lithium supplement agent is 13 μm, and the particle size D50 of the second lithium supplement agent is 6 μm; after the first lithium supplement agent and the second lithium supplement agent are subjected to the first delithiation, the volume ratio of the first lithium supplement agent to the second lithium supplement agent is 1:0.83.

[0080] Example 9

[0081] The difference from Example 1 is that the mass of the first lithium supplement agent is 1.95 g, the mass of the second lithium supplement agent is 0.05 g, and the volume ratio of the first lithium supplement agent to the second lithium supplement agent after delithiation is 1:0.2.

[0082] Example 10

[0083] The difference from Example 1 is that the particle size D50 of the first lithium supplement agent is 15 μm, and the particle size D50 of the second lithium supplement agent is 23 μm.

[0084] Comparative Example 1

[0085] 3 g of the binder polyvinylidene fluoride is weighed and dissolved into 60 g of the solvent N-methyl pyrrolidone, and then 3 g of the conductive agent carbon black is added, and after mixing and stirring, a conductive glue solution is obtained;

[0086] 100 g of the positive electrode material lithium iron phosphate is weighed and added into the conductive glue solution to prepare a positive electrode active paste;

[0087] 2 g of the first lithium supplement agent Li5FeO4 with a particle size D50 of 6 μm is weighed and added into the positive electrode active paste to prepare a lithium-supplemented positive electrode active paste;

[0088] The prepared lithium-supplemented positive electrode active paste is coated on an aluminum foil, and after baking and rolling, a lithium-supplemented positive electrode sheet is obtained.

[0089] Comparative Example 2

[0090] 3 g of the binder polyvinylidene fluoride is weighed and dissolved into 60 g of the solvent N-methyl pyrrolidone, and then 3 g of the conductive agent carbon black is added, and after mixing and stirring, a conductive glue solution is obtained;

[0091] 100 g of the positive electrode material lithium iron phosphate is weighed and added into the conductive glue solution to prepare a positive electrode active paste;

[0092] 2 g of the second lithium supplement agent Li2NiO2 with a particle size D50 of 12 μm is weighed and added into the positive electrode active paste to prepare a lithium-supplemented positive electrode active paste;

[0093] The prepared lithium supplementing positive electrode active slurry is coated on an aluminum foil, and a lithium supplementing positive electrode sheet is obtained after baking and rolling.

[0094] Comparative Example 3

[0095] 3 g of the adhesive polyvinylidene fluoride is weighed and dissolved into 60 g of the solvent N-methyl pyrrolidone, and 3 g of the conductive agent carbon black is continuously added, and a conductive glue solution is obtained after mixing and stirring;

[0096] 100 g of the positive electrode material lithium iron phosphate is weighed and added into the conductive glue solution to prepare a positive electrode active slurry.

[0097] 0.4 g of the first lithium supplementing agent Li5FeO4 with a particle size D50 of 6 μm and 1.6 g of the second lithium supplementing agent Li2NiO2 with a particle size D50 of 12 μm are weighed and added into the positive electrode active slurry to prepare a lithium supplementing positive electrode active slurry.

[0098] The prepared lithium supplementing positive electrode active slurry is coated on an aluminum foil, and a lithium supplementing positive electrode sheet is obtained after baking and rolling.

[0099] Charging and discharging gram capacity:

[0100] The first lithium supplementing agent and the second lithium supplementing agent in Example 1-Example 8 are respectively made into button cells as battery positive electrode materials, and then charged to 4.3 V under the condition of 0.1 C to obtain the first charging gram capacity of the first lithium supplementing agent and the second lithium supplementing agent respectively; the first lithium supplementing agent and the second lithium supplementing agent are respectively made into button cells as battery positive electrode materials, and then discharged to 2.5 V under the condition of 0.1 C to obtain the first discharging gram capacity of the first lithium supplementing agent and the second lithium supplementing agent respectively.

[0101] Volume change amplitude:

[0102] The first lithium supplement anode sheet prepared by Example 1-Example 8 and Comparative Example 1-Comparative Example 3 after the first delithiation is tested by FIB-SEM (Focused Ion Beam-Scanning Electron Microscope), a region with a size of 200 μm*200 μm is selected from different regions of the sheet and is sliced and scanned layer by layer to form a multi-layer two-dimensional image, and the multi-layer two-dimensional image data is reconstructed into three dimensions, the first lithium supplement agent and the second lithium supplement agent are reduced in volume after the first delithiation, but still leave a pore in the sheet which occupies the space of the first lithium supplement agent and the second lithium supplement agent before the first delithiation, the volume of the pore is the volume of the lithium supplement agent occupying the space before the first delithiation, the volume of the first lithium supplement agent and the second lithium supplement agent before and after the first delithiation is measured respectively, and the volume change amplitude and the porosity of the first lithium supplement agent and the second lithium supplement agent before and after the first delithiation are calculated, and the volume ratio of the first lithium supplement agent to the second lithium supplement agent after the first delithiation is obtained, the results are shown in Table 1, wherein the volume change amplitude of the first lithium supplement agent before and after the first delithiation = (the absolute value of the volume of the first lithium supplement agent after the first delithiation-the volume of the first lithium supplement agent before the first delithiation) / the volume of the first lithium supplement agent before the first delithiation*100%, the volume change amplitude of the second lithium supplement agent before and after the first delithiation = (the absolute value of the volume of the second lithium supplement agent after the first delithiation-the volume of the second lithium supplement agent before the first delithiation) / the volume of the second lithium supplement agent before the first delithiation*100%.

[0103] The sum of the volumes of the first lithium supplement agent and the second lithium supplement agent accounts for the volume fraction of the positive active layer:

[0104] The volume of the first lithium supplement agent is obtained by dividing the supplement amount of the lithium supplement agent in the sheet by the true density of the first lithium supplement agent, the volume of the second lithium supplement agent is obtained by dividing the supplement amount of the second lithium supplement agent in the sheet by the true density of the lithium supplement agent, and the sum of the volumes of the first lithium supplement agent and the second lithium supplement agent accounts for the positive active layer, which is obtained by dividing the sum of the volumes of the two lithium supplement agents by the volume of the sheet.

[0105] The lithium supplement anode sheet prepared by Example 1-Example 8 and Comparative Example 1-Comparative Example 3 is converted into a soft package battery together with a negative electrode, a separator and an electrolyte.

[0106] Gas production performance: the soft package batteries prepared by Example 1-Example 8 and Comparative Example 1-Comparative Example 3 are adjusted to 100%, 90%, 80%, 70%, 60%, 50%, 40%, 30%, 20%, 10% and 0% SOC respectively, and after 28 days of storage at 60°C, the weight of the battery is tested by the drainage method, the gas production performance of the battery is calculated and counted by the weight difference, and the results are shown in Table 1.

[0107] Cycling performance: the soft pack batteries prepared from example 1 to example 8 and comparative example 1 to comparative example 3 were cycled at 60℃, 0.5C CC-CV to 3.7V cutoff current was 0.05C charging condition, 0.5C discharge to 2.3V, after 1000 cycles, the capacity retention rate relative to the battery capacity before cycling was observed, and the results are shown in Table 1.

[0108] Rate performance: the soft pack batteries prepared from example 1 to example 8 and comparative example 1 to comparative example 3 were cycled at 25℃, 0.5C CC-CV to 3.7V cutoff current was 0.05C charging condition, 0.1C discharge to 2.3V, the capacity was recorded as C1; at 25℃, 0.5C CC-CV to 3.7V cutoff current was 0.05C charging condition, 2C discharge to 2.3V, the capacity was recorded as C2; the calculation formula of 2C / 0.1C capacity retention rate was: C2 / C1*100%, and the results are shown in Table 1.

[0109] Table 1

[0110] As can be seen from Table 1, the lithium supplementing positive electrode sheet provided by example 1 to example 8 of the present application can effectively inhibit the gas generation phenomenon in the lithium supplementing process while improving the battery capacity and cycling performance by adding appropriate first and second lithium supplementing agents in the positive active layer and controlling the content ratio of the two within a suitable range.

[0111] The preferred embodiments are described in detail above, but the present application is not limited to the above specific embodiments, and those skilled in the art can make various specific changes under the inspiration of the present application without departing from the scope of the present application, which are all within the protection scope of the present application.

Claims

1. A lithium supplemented positive electrode sheet, wherein, The lithium supplement positive plate comprises a current collector and a positive active layer arranged on the current collector, the positive active layer comprising a positive material, a first lithium supplement agent and a second lithium supplement agent; the volume change range of the first lithium supplement agent before and after the first delithiation is greater than that of the second lithium supplement agent; the first charge gram capacity of the first lithium supplement agent is greater than that of the second lithium supplement agent; the first discharge gram capacity of the first lithium supplement agent is less than that of the second lithium supplement agent; the volume ratio of the first lithium supplement agent to the second lithium supplement agent in the lithium supplement positive plate after the first delithiation is 1:(0.2-3).

2. The lithium-supplementing positive electrode sheet according to claim 1, wherein The volume ratio of the first lithium supplement agent to the second lithium supplement agent in the lithium supplement positive plate after the first delithiation is 1:(0.3-3).

3. The lithium-supplementing positive electrode sheet according to claim 1 or 2, wherein The volume of the first lithium supplement agent after the first delithiation is 40%-90% of the volume before the first delithiation, and the volume of the second lithium supplement agent after the first delithiation is 60%-98% of the volume before the first delithiation.

4. The lithium supplemented cathode sheet of any one of claims 1-3, wherein, The porosity of the first lithium supplement agent after the first delithiation is 5%-60%, and the porosity of the second lithium supplement agent after the first delithiation is 1%-40%; the porosity of the second lithium supplement agent after the first delithiation is less than that of the first lithium supplement agent after the first delithiation.

5. The lithium supplemented cathode sheet of any one of claims 1-4, wherein, The first charge gram capacity of the first lithium supplement agent is 400mAh / g-1200mAh / g, and the first charge-discharge efficiency of the first lithium supplement agent is 1%-14%.

6. The lithium supplemented cathode sheet of any one of claims 1-4, wherein, The first charge gram capacity of the second lithium supplement agent is 240mAh / g-550mAh / g, and the first charge-discharge efficiency of the second lithium supplement agent is 15%-45%.

7. The lithium supplemented cathode sheet of any one of claims 1-6, wherein, The first lithium supplement agent comprises one or more of Li5FeO4, Li2O, Li6CoO4, Li5ReO6 and Li4CoO4.

8. The lithium supplemented cathode sheet of any one of claims 1-5, wherein, The second lithium supplementing agent includes one or more of Li2NiO2, Li2CuO2, Li2RuO3, Li2MnO3, Li2MoO3, and Li 0.65 Ni 1.35 O2.

9. The lithium supplemented cathode sheet of any one of claims 1-8, wherein, In the lithium supplement positive plate, the sum of the volumes of the first lithium supplement agent and the second lithium supplement agent accounts for 0.1%-8% of the volume of the positive active layer.

10. The lithium supplemented cathode sheet of any one of claims 1-9, wherein, The particle size D50 of the first lithium supplement agent is 3-15μm.

11. The lithium supplemented cathode sheet of any one of claims 1-9, wherein, The particle size D50 of the second lithium supplement agent is 4-23μm.

12. The lithium supplemented cathode sheet of any one of claims 1-11, wherein, The positive material comprises one or more of lithium manganese iron phosphate, lithium iron phosphate, lithium nickel manganese acid and ternary positive material; the ternary positive material comprises lithium nickel cobalt manganese acid and / or lithium nickel cobalt aluminum acid.

13. The lithium supplemented cathode sheet of any one of claims 1-12, wherein, The positive active layer further comprises a conductive agent and a binder; the conductive agent comprises one or more of conductive graphite, carbon black, acetylene black, super-P, carbon nanotube, graphene, ketchen black and VGCF; the binder comprises one or more of polyvinylidene fluoride, polytetrafluoroethylene, polyimide, polyacrylate, lithium polyacrylate and sodium polyacrylate.

14. The lithium supplemented cathode sheet of any one of claims 1-13, wherein, The first charge capacity of the lithium supplement positive plate is 0.25%-13% greater than that of a positive plate without adding the first lithium supplement agent and the second lithium supplement agent.

15. A method of producing the lithium supplemented cathode sheet according to any one of claims 1 to 14, wherein, Comprising: mixing a positive material, a first lithium supplement agent and a second lithium supplement agent to prepare a lithium supplement positive active paste; arranging the lithium supplement positive active paste on a current collector to obtain a lithium supplement positive plate.

16. The method of producing a lithium supplemented cathode sheet according to claim 15, wherein The sum of the mass of the first lithium supplement agent and the second lithium supplement agent is 0.1%-7.4% of the mass of the positive electrode material; and / or, the mass ratio of the first lithium supplement agent and the second lithium supplement agent is (0.1-10):

1.

17. A lithium-ion battery, wherein, The lithium ion battery (100) comprises a positive electrode sheet (101), a negative electrode sheet (102), and a separator (104) and an electrolyte (103) between the positive electrode sheet (101) and the negative electrode sheet (102), wherein the positive electrode sheet (102) comprises the lithium-supplemented positive electrode sheet according to any one of claims 1-14 or the lithium-supplemented positive electrode sheet prepared by the preparation method according to any one of claims 15-16.

18. An electrical device, comprising: The electric device comprises the lithium ion battery according to claim 17.

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