Positive electrode material, positive electrode sheet, battery cell, battery, and electric device

Abstract

The embodiment of the application provides a kind of positive electrode material, positive pole piece, battery cell, battery and electric device, belong to battery technical field.Positive electrode material includes layered lithium-containing metal oxide, the general formula of layered lithium-containing metal oxide is Li a L x Ni b Co c Mn d M (1‑b‑c‑d) O e N f Wherein, L ion is cation with radius greater than the radius of Li ion, M includes at least one of Mg, Zr, Al, B, Ta, Mo, W, Nb, Sb, La, N includes at least one of F, S, P, 0 < a < 2, 0 ≤ b < 1, 0 ≤ c < 1, 0 ≤ d < 1, 0 < b+c+d ≤ 1, 0 < e ≤ 2, 0 ≤ f < 2, 0 < x ≤ 0.8.The technical scheme of the embodiment of the application is conducive to improving the performance of positive electrode material and the performance of battery cell.

Description

Technical Field

[0001] This application relates to the field of battery technology, and in particular to a positive electrode material, a positive electrode sheet, a battery cell, a battery, and an electrical device. Background Technology

[0002] With increasing environmental pollution, the new energy industry is attracting more and more attention. Within the new energy industry, battery technology is a crucial factor in its development.

[0003] As a material used to prepare the positive electrode sheet of a battery cell, the performance of the positive electrode material is crucial to the performance of the battery cell. Therefore, how to provide a positive electrode material that improves the performance of the battery cell is a technical problem that urgently needs to be solved. Summary of the Invention

[0004] This application is made in view of the above-mentioned problems, and its purpose is to provide a cathode material to improve the performance of a battery cell.

[0005] To achieve the above objectives, this application provides a positive electrode material, a positive electrode sheet, a battery cell, a battery, and an electrical device.

[0006] In a first aspect, a cathode material is provided, the cathode material comprising a layered lithium-containing metal oxide, the layered lithium-containing metal oxide having the general formula Li. a L x Ni b Co c Mn d M (1-b-c-d) O e N f Wherein, L ions are cations with radii larger than that of Li ions, M includes at least one of Mg, Zr, Al, B, Ta, Mo, W, Nb, Sb, and La, N includes at least one of F, S, and P, and 0 <a<2,0≤b<1,0≤c<1,0≤d<1,0<b+c+d≤1,0<e≤2,0≤f<2,0<x≤0.8。

[0007] This application provides a cathode material comprising a layered lithium-containing metal oxide, wherein the general formula of the layered lithium-containing metal oxide is Li. a L x Ni b Co c Mn d M (1-b-c-d) O e N f, where the L ion is a cation with a radius larger than that of the Li ion, M includes at least one of Mg, Zr, Al, B, Ta, Mo, W, Nb, Sb, La, N includes at least one of F, S, P, 0 < a < 2, 0 ≤ b < 1, 0 ≤ c < 1, 0 ≤ d < 1, 0 < b + c + d ≤ 1, 0 < e ≤ 2, 0 ≤ f < 2, 0 < x ≤ 0.8. After the lithium ions are removed from the cathode material, since the radius of the L ion is larger than that of the lithium ion, the range of the Coulomb interaction of the L ion with a large radius is larger than that of the lithium ion, which can weaken the electrostatic repulsion between the oxygen layers after the lithium ions are removed, and can also inhibit phenomena such as atomic misalignment and oxygen ion sliding caused by the vacancies generated by the removal of lithium ions. Therefore, the risk of structural collapse of the cathode material can be reduced, which is beneficial to improving the structural stability of the cathode material; in addition, the radius of the L ion is larger than that of the lithium ion, which can increase the layer spacing between the oxygen layers to a certain extent, so that more release space can be provided for the stress generated during the charge and discharge process of the battery cell, thereby reducing the risk of cracking and oxidation of the cathode material caused by stress, which is beneficial to improving the stability of the cathode material. 0 < x ≤ 0.8. In this way, when the cathode material is used in a battery cell, the battery cell can have a high energy density while improving the stability of the cathode material. Therefore, the technical solution of the embodiment of the present application can improve the structural stability of the cathode material and the performance of the battery cell.

[0008] In one possible implementation, 0.001 ≤ x ≤ 0.5; optionally, 0.001 ≤ x ≤ 0.1. In this way, the battery cell can have a higher energy density while improving the stability of the cathode material.

[0009] In one possible implementation, 0 < c < 0.5. On the one hand, it is beneficial to improve the stability of the layered structure of the cathode material and the cycle performance of the battery cell; on the other hand, it is beneficial to reduce the preparation cost of the cathode material.

[0010] In one possible implementation, 0.3 ≤ b ≤ 0.96. In this way, by reasonably setting the content of Ni in the cathode material, it is beneficial to reasonably set the content of Co in the cathode material, which is beneficial to improving the stability of the layered structure of the cathode material.

[0011] In one possible implementation, 0 < d ≤ 0.3. In this way, by reasonably setting the content of Mn in the cathode material, it is beneficial to reasonably set the content of Co in the cathode material, which is beneficial to improving the stability of the layered structure of the cathode material.

[0012] In one possible implementation, the L ion occupies at least part of the lithium sites in the layered lithium-containing metal oxide, and the position of the Li ion in the layered lithium-containing metal oxide is the lithium site.

[0013] In the layered lithium-containing metal oxide structure, each element has its own arrangement position. In the layered lithium-containing metal oxide structure, the position where lithium ions are located is the lithium site, and L ions occupy at least part of the lithium sites in the layered lithium-containing metal oxide structure. The L ions have a large radius and are stable in occupying the lithium sites, which is beneficial to reducing the phenomenon of lithium-nickel mixing and thus beneficial to improving the stability of the layered structure.

[0014] In one possible implementation, the L ion element includes at least one of alkali metal elements, alkaline earth metal elements, transition metal elements, and other main group metal elements other than lithium element. In this way, it is convenient to select appropriate elements for doping according to actual needs.

[0015] In one possible implementation, the alkali metal element includes at least one of Na, K, Rb, and Cs; the alkaline earth metal element includes at least one of Mg, Ca, and Sr; the transition metal element includes Y; the other main group metal element includes Bi.

[0016] In the above technical solution, the above elements are convenient for doping and convenient for the preparation of the positive electrode material; in addition, by doping sodium ions, potassium ions, rubidium ions, cesium ions, etc. into the positive electrode material, it is beneficial to improve the stability of the positive electrode material.

[0017] In one possible implementation, the operating voltage V of the positive electrode material satisfies: V = kx, where 0 < k < 100. In this way, it is convenient to reasonably set the value of y according to the required positive electrode material to meet the requirement of the positive electrode material for the operating voltage.

[0018] In one possible implementation, the Poisson's ratio S of the positive electrode material is less than 0. In this way, it is beneficial to improve the stability of the positive electrode material, and at the same time, it is also beneficial to increase the operating voltage of the battery cell.

[0019] In one possible implementation, the Poisson's ratio S of the positive electrode material satisfies: -2 < S < 0; optionally, -0.2 ≤ S ≤ -0.05. In this way, the positive electrode material has high stability, and at the same time, it is also beneficial to increase the operating voltage of the battery cell, thereby increasing the energy density of the battery cell.

[0020] In one possible implementation, the operating voltage V of the positive electrode material satisfies: V = -TS, where 0 < T < 100. In this way, it is convenient to reasonably set the value of S according to the required positive electrode material to meet the requirement of the positive electrode material for the operating voltage.

[0021] In a second aspect, the present application provides a positive electrode plate, including the positive electrode material in the first aspect and any one of its possible implementations.

[0022] In a third aspect, the present application provides a battery cell, including the positive electrode sheet described in the second aspect.

[0023] In a possible implementation, the operating voltage of the battery cell is 2V to 5V; optionally, it is 4.4V to 5V. In this way, it is beneficial to improve the energy density of the battery cell.

[0024] In a fourth aspect, the present application provides a battery, including the battery cell in the third aspect and any one of its possible implementations.

[0025] In a fifth aspect, the present application provides an electrical device, including the battery described in the fourth aspect.

[0026] The present application provides a positive electrode material. The positive electrode material includes a layered lithium-containing metal oxide. The general formula of the layered lithium-containing metal oxide is Li a L x Ni b Co c Mn d M (1-b-c-d) O e N f , where the L ion is a cation with a radius larger than that of the Li ion, M includes at least one of Mg, Zr, Al, B, Ta, Mo, W, Nb, Sb, La, N includes at least one of F, S, P, 0 < a < 2, 0 < b ≤ 0.96, 0 < c < 1, 0 < d < 1, 0 < b + c + d ≤ 1, 0 < e ≤ 2, 0 ≤ f < 2, 0 < x ≤ 0.8. After the lithium ions are removed from the positive electrode material, since the radius of the L ion is larger than that of the lithium ion, the range of the Coulomb interaction of the L ion with a large radius is larger than that of the lithium ion, which can weaken the electrostatic repulsion between the oxygen layers after the lithium ions are removed, and can also inhibit phenomena such as atomic misalignment and oxygen ion sliding caused by the vacancies generated by the removal of lithium ions. Therefore, the risk of structural collapse of the positive electrode material can be reduced, which is beneficial to improving the structural stability of the positive electrode material; in addition, the radius of the L ion is larger than that of the lithium ion, which can increase the layer spacing between the oxygen layers to a certain extent, so that more release space can be provided for the stress generated during the charge and discharge process of the battery cell, and thus the risk of cracking and oxidation of the positive electrode material caused by stress can be reduced, which is beneficial to improving the stability of the positive electrode material. 0 < x ≤ 0.8. In this way, when the positive electrode material is used in a battery cell, the battery cell can have a high energy density while improving the stability of the positive electrode material. Therefore, the technical solution of the present application can improve the performance of the positive electrode material and the battery cell. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 is a schematic diagram of a battery cell according to an embodiment of the present application;

[0028] Figure 2 This is a schematic diagram of a battery module according to an embodiment of this application;

[0029] Figure 3 This is a schematic diagram of a battery according to an embodiment of this application;

[0030] Figure 4 This is a schematic diagram of an electrical device according to an embodiment of this application. Detailed Implementation

[0031] The following detailed description, with appropriate reference to the accompanying drawings, discloses embodiments of the positive electrode material, positive electrode sheet, battery cell, battery, and power device of this application. However, unnecessary detailed descriptions may be omitted. For example, detailed descriptions of well-known matters and repetitive descriptions of practically identical structures may be omitted. This is to avoid unnecessarily lengthy descriptions and to facilitate understanding by those skilled in the art. Furthermore, the accompanying drawings and the following description are provided for the purpose of enabling those skilled in the art to fully understand this application and are not intended to limit the subject matter of the claims.

[0032] The "range" disclosed in this application is defined by a lower limit and an upper limit. A given range is defined by selecting a lower limit and an upper limit, which define the boundaries of a particular range. Ranges defined in this way can include or exclude endpoints and can be arbitrarily combined; that is, any lower limit can be combined with any upper limit to form a range. For example, if ranges of 60-120 and 80-110 are listed for a specific parameter, it is expected that ranges of 60-110 and 80-120 are also included. Furthermore, if minimum range values ​​of 1 and 2 are listed, and if maximum range values ​​of 3, 4, and 5 are listed, then the following ranges are all expected: 1-3, 1-4, 1-5, 2-3, 2-4, and 2-5. In this application, unless otherwise stated, the numerical range "ab" represents a shortened representation of any combination of real numbers between a and b, where a and b are real numbers. For example, the numerical range "0-5" indicates that all real numbers between "0-5" have been listed in this article; "0-5" is simply a shortened representation of these numerical combinations. Furthermore, when a parameter is stated as an integer ≥2, it is equivalent to disclosing that the parameter is, for example, an integer such as 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, etc.

[0033] Unless otherwise specified, all embodiments and optional embodiments of this application can be combined to form new technical solutions.

[0034] Unless otherwise specified, all technical features and optional technical features of this application may be combined to form new technical solutions.

[0035] Unless otherwise specified, all steps in this application may be performed sequentially or randomly, preferably sequentially. For example, the method includes steps (a) and (b), indicating that the method may include steps (a) and (b) performed sequentially, or it may include steps (b) and (a) performed sequentially. For example, the mention that the method may also include step (c) indicates that step (c) may be added to the method in any order. For example, the method may include steps (a), (b), and (c), or it may include steps (a), (c), and (b), or it may include steps (c), (a), and (b), etc.

[0036] Unless otherwise specified, the terms "comprising" and "including" as used in this application can be open-ended or closed-ended. For example, "comprising" and "including" can mean that other components not listed may also be included, or that only the listed components may be included.

[0037] Unless otherwise specified, the term "or" is inclusive in this application. For example, the phrase "A or B" means "A, B, or both A and B". More specifically, the condition "A or B" is satisfied by any of the following conditions: A is true (or exists) and B is false (or does not exist); A is false (or does not exist) and B is true (or exists); or both A and B are true (or exist).

[0038] Cathode materials, as the materials used to prepare the positive electrode sheet of a battery cell, are crucial to the performance of the battery cell. Cathode materials can be mainly classified into three categories according to their structure: layered oxides, such as LiMO2, where M includes at least one of Co, Ni, and Mn; spinel oxides, such as LiMn2O4; and olivine oxides, such as LiFePO4. Layered cathode materials are widely used due to their high specific energy and high specific capacity. In layered cathode materials, each metal oxide layer has two oxygen atom planes, and transition metal atoms occupy interstitial vacancies. Lithium ions are embedded in the interstitials between the metal oxide layers to form an atomically thick lithium layer. During the charging and discharging process of the battery cell, lithium ions can move two-dimensionally from their respective planes, i.e., lithium ion extraction and insertion occur.

[0039] Currently, the operating voltage of the cathode material with a layered structure is relatively low, resulting in limited improvement in the energy density of a single battery cell. In some treatment methods, the energy density of a single battery cell can be increased by raising the charge-discharge voltage (also known as the operating voltage) of the single battery cell. However, when the charge-discharge voltage of the single battery cell is relatively high, on the one hand, during the charging process of the single battery cell, the number of lithium ions in the cathode material is relatively small, and the cathode material is in a lithium-deficient state, and the structure of the cathode material is prone to collapse, thus affecting the performance of the single battery cell; on the other hand, the stress generated during the charge-discharge process of the single battery cell may cause the cathode material to crack, and further lead to increased oxidation of the cathode material, affecting the performance of the single battery cell.

[0040] The applicant has found through research that by doping cations with an ionic radius larger than that of lithium ions in the cathode material and reasonably setting the content of the doped cations, the stability of the cathode material can be improved, which is beneficial to improving the performance of a single battery cell. In view of this, an embodiment of the present application provides a cathode material including a layered lithium-containing metal oxide. The general formula of the layered lithium-containing metal oxide is Li a L x Ni b Co c Mn d M (1-b-c-d) O e N f , where the L ion is a cation with an ionic radius larger than that of the Li ion, M includes at least one of Mg, Zr, Al, B, Ta, Mo, W, Nb, Sb, La, N includes at least one of F, S, P, 0 < a < 2, 0 ≤ b < 1, 0 ≤ c < 1, 0 ≤ d < 1, 0 < b + c + d ≤ 1, 0 < e ≤ 2, 0 ≤ f < 2, 0 < x ≤ 0.8. In this way, the stability of the cathode material can be improved, which is beneficial to improving the performance of a single battery cell.

[0041] [Cathode Material]

[0042] An embodiment of the present application provides a cathode material. The cathode material includes a layered lithium-containing metal oxide. The general formula of the layered lithium-containing metal oxide is Li a L x Ni b Co c Mn d M (1-b-c-d) O e N f , where the L ion is a cation with an ionic radius larger than that of the Li ion, M includes at least one of Mg, Zr, Al, B, Ta, Mo, W, Nb, Sb, La, N includes at least one of F, S, P, 0 < a < 2, 0 ≤ b < 1, 0 ≤ c < 1, 0 ≤ d < 1, 0 < b + c + d ≤ 1, 0 < e ≤ 2, 0 ≤ f < 2, 0 < x ≤ 0.8.

[0043] Layered lithium-containing metal oxides can refer to lithium-containing salts that include a metallic element. For example, layered lithium-containing metal oxides can be lithium nickel cobalt manganese oxide. "Layered" can also refer to the layered crystal structure of the lithium-containing metal oxide.

[0044] L-ions are cations with a radius larger than that of lithium ions. Therefore, after lithium ions are extracted from the cathode material, the larger radius of the L-ion results in a greater Coulombic effect range compared to lithium ions. This weakens the electrostatic repulsion between oxygen layers after lithium ion extraction and suppresses atomic misalignment and oxygen ion slippage caused by vacancies. This reduces the risk of structural collapse in the cathode material and improves its stability. Furthermore, the larger radius of the L-ion increases the spacing between oxygen layers, providing more space for stress release during charging and discharging. This reduces the risk of stress-induced cracking and oxidation in the cathode material, further enhancing its stability.

[0045] The following conditions apply: 0 ≤ b < 1, 0 ≤ c < 1, 0 ≤ d < 1, 0 < b + c + d ≤ 1. For example, b can be 0, 0.1, 0.3, 0.5, 0.9, or any value within the above range; c can be 0, 0.1, 0.3, 0.5, 0.9, or any value within the above range; d can be 0, 0.1, 0.3, 0.5, 0.9, or any value within the above range. This application does not impose specific limitations on these conditions, as long as the above conditions are met. In this application embodiment, b, c, and d do not all have to be 0 simultaneously; one or two of them can be 0. For example, the layered lithium-containing metal oxide is Li... 0.5 Na 0.5 NiO2, Li 0.5 Na 0.5 CoO2, Li 0.5 Na 0.5 MnO2, Li 0.5 Na 0.5 Ni 0.9 Al 0.1 O2, etc.

[0046] M includes at least one of Mg, Zr, Al, B, Ta, Mo, W, Nb, Sb, and La, where 0 < b + c + d ≤ 1. When b + c + d < 1, the layered lithium-containing metal oxide includes element M, and the layered lithium-containing metal oxide can have higher stability. When b + c + d = 1, the layered lithium-containing metal oxide does not include element M, and the general formula of the layered lithium-containing metal oxide can be Li. a L x Ni b Coc Mn d O e N f 。

[0047] It can be understood that the position of M ions in the layered lithium-containing metal oxide structure can be the position replacing part of the transition metals. For example, in the case where the layered lithium-containing metal oxide is a nickel-cobalt-manganese-based ternary material, M ions can replace part of the manganese position, nickel position or cobalt position.

[0048] N includes at least one of F, S, and P, 0 ≤ f < 2. For example, f is 0, 0.5, 1, 1.5 or any other value within the above range. When f = 0, the layered lithium-containing metal oxide does not include the N element, and the general formula of the layered lithium-containing metal oxide can be Li a L x Ni b Co c Mn d M (1-b-c-d) O e 。

[0049] It can be understood that the position of N ions in the layered lithium-containing metal oxide structure can be the position replacing part of O. Optionally, e + f = 2.

[0050] 0 < a < 2, and the value of a can be flexibly set according to the required capacity of the battery cell. For example, a is 0.9, 1, 1.2, 1.5, 1.8 or any other value within the above range. When a is greater than 1, the layered lithium-containing metal oxide can be a lithium-rich metal oxide, which is beneficial to increasing the content of active lithium in the positive electrode material, thereby being beneficial to increasing the capacity of the battery cell.

[0051] 0 < x ≤ 0.8. For example, x is 0.001, 0.005, 0.1, 0.5, 0.6, 0.8 or any other value within the above range. On the one hand, x > 0, and the inclusion of L ions in the layered lithium-containing metal oxide is beneficial to improving the stability of the positive electrode material; on the other hand, x ≤ 0.8, and the content of L ions is within a suitable range, which can avoid the situation where the content of lithium ions is low due to the excessive content of L ions, so that the battery cell can have relatively appropriate cycling performance under the condition of having a high energy density.

[0052] It should be noted that the general formula for layered lithium-containing metal oxides given in the embodiments of this application can be a general formula under ideal conditions. Ideally, it can include the addition of lithium-containing layered oxides that satisfy the above general formula during the preparation of cathode materials. After a battery cell is prepared from the cathode material, due to various factors such as lithium ion insertion / extraction or consumption, the actual lithium ion content may be reduced compared to the above general formula. Similarly, the actual oxygen ion content may also be reduced. For example, when the lithium-containing layered metal oxide is Li... 0.5 Na 0.5 In the case of NiO2, the actual measured general formula might be Li. 0.5+ e Na 0.5+g NiO 2+f , e<0, g<0, f<0.

[0053] The positive electrode material in the embodiments of this application can be used as a positive electrode active material. For example, it can be mixed with binder, conductive agent and corresponding solvent to prepare a slurry, which is then coated on the positive electrode current collector to prepare a positive electrode sheet.

[0054] This application provides a cathode material comprising a layered lithium-containing metal oxide, wherein the general formula of the layered lithium-containing metal oxide is Li. a L x Ni b Co c Mn d M (1-b-c-d) O e N f, where the L ion is a cation with a radius larger than that of the Li ion, M includes at least one of Mg, Zr, Al, B, Ta, Mo, W, Nb, Sb, and La, N includes at least one of F, S, and P, 0 < a < 2, 0 ≤ b < 1, 0 ≤ c < 1, 0 ≤ d < 1, 0 < b + c + d ≤ 1, 0 < e ≤ 2, 0 ≤ f < 2, and 0 < x ≤ 0.8. After the lithium ions are removed from the cathode material, since the radius of the L ion is larger than that of the lithium ion, the range of the Coulomb interaction of the L ion with a large radius is larger than that of the lithium ion, which can weaken the electrostatic repulsion between the oxygen layers after the lithium ions are removed, and can also inhibit phenomena such as atomic misalignment and oxygen ion sliding caused by the vacancies generated during the removal of lithium ions. Therefore, the risk of structural collapse of the cathode material can be reduced, which is beneficial to improving the structural stability of the cathode material; in addition, since the radius of the L ion is larger than that of the lithium ion, the interlayer spacing between the oxygen layers can be increased to a certain extent, which can provide more space for the release of the stress generated during the charge and discharge process of the battery cell, thereby reducing the risk of cracking and oxidation of the cathode material caused by stress, and being beneficial to improving the stability of the cathode material. 0 < x ≤ 0.8. In this way, when the cathode material is used in a battery cell, the battery cell can have high cycling performance while improving the stability of the cathode material. Therefore, the technical solution of the present application can improve the structural stability of the cathode material and the performance of the battery cell.

[0055] In some embodiments, 0.001 ≤ x ≤ 0.5. In this way, the cathode material has high stability, and the battery cell has a high operating voltage and good cycling performance.

[0056] Optionally, 0.001 ≤ x ≤ 0.1. In this way, the battery cell has a high operating voltage and good cycling performance.

[0057] In some embodiments, 0 < a < 1 and a + x = 1. In this way, the cathode material satisfying this proportional relationship is convenient to prepare and obtain, which is beneficial to reducing the production cost.

[0058] In some embodiments, 0 < c < 0.5. In this way, by reasonably setting the content of Co in the cathode material, on the one hand, it is beneficial to improving the stability of the layered structure of the cathode material and the cycling performance of the battery cell; on the other hand, it is beneficial to reducing the preparation cost of the cathode material.

[0059] In some embodiments, 0.3 ≤ b ≤ 0.96. In this way, by reasonably setting the content of Ni in the cathode material, it is beneficial to reasonably setting the content of Co in the cathode material, and is beneficial to improving the stability of the layered structure of the cathode material.

[0060] In some embodiments, 0 < d ≤ 0.3. Thus, by reasonably setting the content of Mn in the cathode material, it is beneficial to reasonably set the content of Co in the cathode material, thereby facilitating the improvement of the stability of the layered structure of the cathode material.

[0061] In some embodiments, 0.3 ≤ b ≤ 0.96, 0 < c < 0.5, 0 < d ≤ 0.3. By reasonably setting the contents of Ni, Co, and Mn in the cathode material, it is beneficial to balance the operating voltage and cycling performance of the battery cell.

[0062] In some embodiments, L ions occupy at least part of the lithium sites in the layered lithium-containing metal oxide, and the positions of Li ions in the layered lithium-containing metal oxide are lithium sites.

[0063] In the structure of the layered lithium-containing metal oxide, each element has its own arrangement position. In the layered lithium-containing metal oxide structure, the positions where lithium ions are located are lithium sites, and L ions occupy at least part of the lithium sites in the layered lithium-containing metal oxide structure. The radius of L ions is large, and occupying lithium sites is stable, which is beneficial to reducing the phenomenon of lithium-nickel mixing, thereby facilitating the improvement of the stability of the layered structure.

[0064] In some embodiments, the L ion element includes at least one of alkali metal elements, alkaline earth metal elements, transition metal elements, and other main group metal elements other than lithium element. Thus, it is convenient to select appropriate elements for doping according to actual needs.

[0065] In some embodiments, the alkali metal elements include at least one of Na, K, Rb, and Cs; the alkaline earth metal elements include at least one of Mg, Ca, and Sr; the transition metal element includes Y; and the other main group metal element includes Bi.

[0066] The above elements are convenient for doping and for the preparation of the cathode material; in addition, by doping sodium ions, potassium ions, rubidium ions, cesium ions, etc. into the cathode material, it is beneficial to improve the stability of the cathode material.

[0067] In some embodiments, the operating voltage V of the cathode material satisfies: V = kx, where 0 < k < 100.

[0068] The unit of k is the same as the unit of voltage V, both being volts (V), and the value of k can be determined according to the operating voltage V and the content y of L ions.

[0069] The operating voltage of the cathode material can be understood as the voltage of the battery cell when the cathode material is fabricated into a cathode electrode sheet and used in the battery cell. This voltage can be understood as the charge-discharge voltage of the battery cell, and in some cases, it can also be understood as the upper or lower limit of the charge-discharge voltage of the battery cell.

[0070] The higher the voltage of the battery cell, the higher the number of lithium ions extracted from the positive electrode material, and thus the greater the possibility of the structure of the positive electrode material changing. The operating voltage V of the positive electrode material and the content y of L ions satisfy a certain relationship. By reasonably setting y, the requirement for the operating voltage V can be met while the positive electrode material maintains good structural stability.

[0071] In the above embodiments, it is convenient to reasonably set the value of y according to the required positive electrode material to meet the requirement of the positive electrode material for the operating voltage.

[0072] In some embodiments, the Poisson's ratio S of the positive electrode material is less than 0.

[0073] For the positive electrode material of the embodiments of the present application, the fact that the Poisson's ratio S of the positive electrode material is less than 0 is reflected in that when the positive electrode material is stretched in the lithium ion insertion / extraction direction, the positive electrode material expands in the direction perpendicular to the lithium ion insertion / extraction direction; when the positive electrode material is compressed in the lithium ion insertion / extraction direction, the positive electrode material contracts in the direction perpendicular to the lithium ion insertion / extraction direction. In other words, when the size of the positive electrode material becomes larger in one direction, the sizes of the positive electrode material in the other two directions perpendicular to the above direction become smaller.

[0074] The Poisson's ratio S of the positive electrode material may refer to the Poisson's ratio of the lattice structure of the positive electrode material itself.

[0075] During the continuous charge and discharge of the battery cell, stress will be generated. When the battery cell is in a high voltage state, the positive electrode material is in a lithium-deficient state, and the relatively large stress generated may cause the positive electrode material to crack. The cracked positive electrode material is easily oxidized, affecting the performance of the battery cell. The Poisson's ratio S of the positive electrode material of the present application is less than 0. When the structure of the positive electrode material is stretched in the lithium ion extraction direction, due to the Poisson's ratio S of the positive electrode material being less than 0, the positive electrode material will not contract in the direction perpendicular to the lithium ion extraction direction, thereby reducing the possibility of the positive electrode material cracking and further reducing the possibility of the positive electrode material being oxidized.

[0076] In the above embodiments, the Poisson's ratio S of the positive electrode material is less than 0. In this way, it is beneficial to improve the stability of the positive electrode material, and at the same time, it is also beneficial to increase the operating voltage of the battery cell.

[0077] In some embodiments, the Poisson's ratio S of the positive electrode material satisfies: -2 < S < 0; optionally, -0.2 ≤ S ≤ -0.05. In this way, the positive electrode material has high stability, and at the same time, it is also beneficial to increase the operating voltage of the battery cell, thereby increasing the energy density of the battery cell.

[0078] In some embodiments, the operating voltage V of the positive electrode material satisfies: V = -TS, where 0 < T < 100.

[0079] The unit of T is the same as that of voltage V, both being volts (V). The value of T can be determined based on the operating voltage V and the Poisson's ratio S of the positive electrode material.

[0080] The operating voltage V of the positive electrode material is related to its Poisson's ratio S. In the above embodiment, it is convenient to reasonably set the value of S according to the required operating voltage of the positive electrode material, so as to meet the operating voltage requirements of the positive electrode material.

[0081] [Positive electrode plate]

[0082] This application provides a positive electrode sheet, including the positive electrode material described in the above embodiments.

[0083] In some embodiments, the positive electrode sheet includes a positive current collector and a coating disposed on the positive current collector, wherein the coating includes the positive electrode material in the above embodiments.

[0084] In some embodiments, the coating includes an adhesive. As an example, the adhesive may include at least one of polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), PVDF-tetrafluoroethylene-propylene terpolymer, PVDF-hexafluoropropylene-tetrafluoroethylene terpolymer, tetrafluoroethylene-hexafluoropropylene copolymer, and fluorinated acrylate resin.

[0085] In some embodiments, the coating includes a conductive agent. As an example, the conductive agent may include at least one selected from superconducting carbon, acetylene black, carbon black, Ketjen black, carbon dots, carbon nanotubes, graphene, and carbon nanofibers.

[0086] In some embodiments, the positive current collector may be a metal foil or a composite current collector. For example, aluminum foil may be used as the metal foil. The composite current collector may include a polymer substrate and a metal layer formed on at least one surface of the polymer substrate. The composite current collector may be formed by forming a metal material (aluminum, aluminum alloy, nickel, nickel alloy, titanium, titanium alloy, silver and silver alloy, etc.) on a polymer substrate (such as a substrate of polypropylene (PP), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polystyrene (PS), polyethylene (PE), etc.).

[0087] [Battery cell]

[0088] This application provides a battery cell including the positive electrode sheet described in the above embodiments.

[0089] The embodiments of this application do not impose any particular restrictions on the shape of the battery cell; it can be cylindrical, square, or any other arbitrary shape.

[0090] Figure 1 This is a schematic diagram of a battery cell according to an embodiment of this application. Figure 1As shown, the battery cell 3 includes a housing 31, a cover plate 32, and an electrode assembly 33 disposed in the housing 31.

[0091] The electrode assembly 33 can be manufactured from the positive electrode, negative electrode and separator of the present application embodiment by a winding process or a stacking process.

[0092] Optionally, the battery cell 3 also includes an electrolyte. The electrolyte can be solid, semi-solid, or liquid, and this application embodiment does not impose specific limitations on this.

[0093] In some embodiments, individual battery cells can be assembled into a battery module. The number of individual battery cells contained in a battery module can be one or more, and the specific number can be selected by those skilled in the art based on the application and capacity of the battery module.

[0094] Figure 2 This is a schematic diagram of a battery module according to an embodiment of this application. (Refer to...) Figure 2 In the battery module 4, multiple battery cells 3 can be arranged sequentially along the length of the battery module 4. Of course, they can also be arranged in any other way. Furthermore, these multiple battery cells 3 can be fixed in place using fasteners.

[0095] Optionally, the battery module 4 may also include a housing with a receiving space in which multiple battery cells 3 are housed.

[0096] In some embodiments, the operating voltage of a single battery cell is 2V to 5V; optionally, it is 4.4V to 5V. This is beneficial for improving the energy density of the single battery cell.

[0097] When the operating voltage of a battery cell is high, such as above 4.4V, the positive electrode material exhibits higher stability, thus maintaining its original structure. Furthermore, the operating voltage of a battery cell is related to its energy density; a higher operating voltage is more conducive to increasing the energy density of the battery cell. Therefore, battery cells can have higher operating voltages, which is beneficial for improving their energy density.

[0098] [Battery]

[0099] This application provides a battery comprising the battery cell described in the above embodiments.

[0100] Figure 3 This is a schematic diagram of a battery according to an embodiment of this application. Figure 3 As shown, this application provides a battery 5, including the battery cell 3 in any of the above embodiments.

[0101] Battery cells 3 can be directly assembled into battery 5, or they can be first assembled into battery modules, and then multiple battery modules can be assembled into battery 5.

[0102] [Electrical appliances]

[0103] This application provides an electrical device including the battery described in the above embodiments.

[0104] Figure 4 This is a schematic diagram of an electrical device according to an embodiment of this application. Figure 4 As shown, this application provides an electrical device 6, which includes the battery 5 in the above embodiment.

[0105] The following describes embodiments of this application. The embodiments described below are exemplary and are only used to explain this application, and should not be construed as limiting this application. Where specific techniques or conditions are not specified in the embodiments, they are performed according to the techniques or conditions described in the literature in this field or according to the product instructions. Reagents or instruments used, unless otherwise specified, are all conventional products that can be obtained commercially.

[0106] [Example]

[0107] Example 1

[0108] The general formula of the cathode material in Example 1 is Li 0.5 Na 0.5 Ni 0.5 Co 0.2 Mn 0.3 O2, prepared as follows. In Example 1, a is 0.5 and x is 0.5.

[0109] (1) Add nickel acetate, cobalt acetate, and manganese acetate to deionized water according to the stoichiometric ratio and stir evenly to obtain a transition metal salt solution; (2) Quickly pour sodium carbonate solution into the above transition metal salt solution, continue the reaction for 9 hours, and then let it stand for 4 hours to obtain the primary particles after growth; (3) Wash the above primary particles with deionized water 3 times, dry them in a blower dryer, and then vacuum dry them at 100°C for 12 hours. Collect the dried solid, which is the precursor; (4) Mix the precursor with lithium carbonate and sodium carbonate in a molar ratio of 1:0.535:0.535 evenly and grind them (wherein, the excess lithium carbonate is to compensate for the loss of lithium in high-temperature calcination); (5) Transfer the fully ground solid powder to a crucible and place it in a muffle furnace with programmed temperature rise for calcination. The calcination program is as follows: (6) Pre-calcine at 500°C from room temperature for 5 hours, and then calcine at 800°C for 12 hours. The heating rate is 3°C / min. -1 After cooling to room temperature, the material is collected to obtain the aforementioned cathode material.

[0110] Example 2

[0111] The general formula of the cathode material in Example 2 is Li0.4 Na 0.6 Ni 0.5 Co 0.2 Mn 0.3 O2. In Example 2, a is 0.4 and x is 0.6.

[0112] The preparation method of Example 2 is largely the same as that of Example 1, except that the molar ratio in step (4) is different. In Example 2, the precursor, lithium carbonate, and sodium carbonate are in a molar ratio of 1:0.428:0.642.

[0113] Example 3

[0114] The general formula of the cathode material in Example 3 is Li 0.3 Na 0.7 Ni 0.5 Co 0.2 Mn 0.3 O2. In Example 3, a is 0.3 and x is 0.7.

[0115] The preparation method of Example 3 is largely the same as that of Example 1, except that the molar ratio in step (4) is different. In Example 3, the precursor, lithium carbonate, and sodium carbonate are in a molar ratio of 1:0.321:0.749.

[0116] Example 4

[0117] The general formula of the cathode material in Example 4 is Li 0.2 Na 0.8 Ni 0.5 Co 0.2 Mn 0.3 O2. In Example 4, a is 0.2 and x is 0.8.

[0118] The preparation method of Example 4 is largely the same as that of Example 1, except that the molar ratio in step (4) is different. In Example 3, the precursor, lithium carbonate, and sodium carbonate were prepared in a molar ratio of 1:0.214:0.856.

[0119] Example 5

[0120] The general formula of the cathode material in Example 5 is Li 0.9 Na 0.1 Ni 0.5 Co 0.2 Mn 0.3 O2. In Example 5, a is 0.9 and x is 0.1.

[0121] The preparation method of Example 5 is largely the same as that of Example 1, except that the molar ratio in step (4) is different. In Example 5, the precursor, lithium carbonate, and sodium carbonate are in a molar ratio of 1:0.963:0.107.

[0122] Example 6

[0123] The general formula of the cathode material in Example 6 is Li 0.99 Na 0.01 Ni 0.5 Co 0.2 Mn 0.3 O2. In Example 6, a is 0.99 and x is 0.01.

[0124] The preparation method of Example 6 is largely the same as that of Example 1, except that the molar ratio in step (4) is different. In Example 6, the precursor, lithium carbonate, and sodium carbonate are in a molar ratio of 1:1.056:0.011.

[0125] Example 7

[0126] The general formula of the cathode material in Example 7 is Li 0.999 Na 0.001 Ni 0.5 Co 0.2 Mn 0.3 O2. In Example 6, a is 0.999 and x is 0.001.

[0127] The preparation method of Example 7 is largely the same as that of Example 1, except that the molar ratio in step (4) is different. In Example 7, the precursor, lithium carbonate, and sodium carbonate are in a molar ratio of 1:1.068:0.002.

[0128] Examples 8-13

[0129] The general formula of the cathode material in Example 8 is Li 0.5 Na 0.5 Ni 0.3 Co 0.4 Mn 0.3 O2, the general formula of the positive electrode material in Example 9 is Li 0.5 Na 0.5 Ni 0.4 Co 0.3 Mn 0.3 O2, the general formula of the positive electrode material in Example 10 is Li 0.5 Na 0.5 Ni 0.7 Co 0.1 Mn 0.2 O2, the general formula of the positive electrode material in Example 11 is Li 0.5 Na 0.5NiO2, the general formula of the cathode material in Example 12 is Li 0.5 Na 0.5 CoO2, the general formula of the cathode material in Example 13 is Li 0.5 Na 0.5 MnO2.

[0130] The difference between Examples 8-13 and Example 1 lies in the content of Co, Mn, and Ni.

[0131] Example 14

[0132] The general formula of the cathode material in Example 14 is Li 0.5 Na 0.1 K 0.2 Cs 0.05 Rb 0.15 Ni 0.5 Co 0.2 Mn 0.3 O2. In Example 14, a is 0.5 and x is 0.5.

[0133] The preparation method of Example 14 is largely the same as that of Example 1, except that the molar ratio in step (4) is different. In Example 14, the precursor and lithium carbonate, sodium carbonate, potassium carbonate, cesium carbonate and rubidium carbonate are in a molar ratio of 1:0.535:0.107:0.216:0.0535:0.1605.

[0134] Examples 15-20

[0135] The general formula of the cathode material in Example 15 is Li. 0.5 K 0.5 Ni 0.5 Co 0.2 Mn 0.3 O2, the general formula of the positive electrode material in Example 16 is Li 0.5 Rb 0.5 Ni 0.5 Co 0.2 Mn 0.3 O2, the general formula of the positive electrode material in Example 17 is Li 0.5 Cs 0.5 Ni 0.5 Co 0.2 Mn 0.3 O2, the general formula of the positive electrode material in Example 18 is Li 0.5 Mg 0.5 Ni 0.5 Co 0.2 Mn 0.3 O2, the general formula of the positive electrode material in Example 19 is Li 0.5 Y 0.5 Ni 0.5 Co0.2 Mn 0.3 O2, the general formula of the positive electrode material in Example 20 is Li 0.5 Bi 0.5 Ni 0.5 Co 0.2 Mn 0.3 O2.

[0136] The difference between Examples 15-20 and Example 1 is that the L element used for doping is different.

[0137] Examples 21-23

[0138] The general formula of the cathode material in Example 21 is Li 1.5 Na 0.5 Ni 0.5 Co 0.2 Mn 0.3 O2, the general formula of the positive electrode material in Example 22 is Li 1.2 Na 0.8 Ni 0.5 Co 0.2 Mn 0.3 O2, the general formula of the positive electrode material in Example 23 is Li 0.8 Na 0.8 Ni 0.5 Co 0.2 Mn 0.3 O2.

[0139] The difference between Examples 21-23 and Example 1 is that the value of x+a is different.

[0140] In Examples 21-23, the precursors were mixed with lithium carbonate and sodium carbonate in molar ratios of 1:1.605:0.535; 1:1.284:0.856; and 1:0.856:0.856, respectively.

[0141] Examples 24-25

[0142] In Examples 24-25, element M was doped.

[0143] The general formula of the cathode material in Example 24 is Li 0.5 Na 0.5 Ni 0.5 Co 0.2 Mn 0.2 Al 0.1 O2, in Example 24, M is Al.

[0144] The general formula of the cathode material in Example 25 is Li 0.5 Na 0.5 Ni 0.5 Co 0.2 Mn 0.2 Mg0.1 O2, in Example 25, M is Mg.

[0145] Comparative Example 1

[0146] The general formula of the cathode material in Comparative Example 1 is LiNi. 0.5 Co 0.2 Mn 0.2 Al 0.1 O2. In Comparative Example 1, the cathode material was not doped with cations whose ionic radii are larger than those of lithium ions.

[0147] Comparative Example 2

[0148] The general formula of the cathode material in Comparative Example 2 is LiNi. 0.5 Co 0.2 Mn 0.3 O2. In Comparative Example 2, the cathode material was not doped with cations whose ionic radii are larger than those of lithium ions.

[0149] [Preparation of the positive electrode sheet]

[0150] The above-mentioned positive electrode material, polyvinylidene fluoride binder, and carbon black conductive agent are mixed at a mass ratio of 90:5:5. Using N-methyl-pyrrolidone as a solvent, the amount of solvent added is adjusted to control the slurry viscosity at 100-20000 mPa·s. The slurry is then coated onto the positive electrode current collector using a coating machine or sprayer. After drying at 85°C, it is cold-pressed, then trimmed, cut into sheets, and slit. Finally, it is dried under vacuum at 85°C for 4 hours, and electrode tabs are welded to produce the positive electrode sheet of the battery cell that meets the requirements.

[0151] [Preparation of battery cells]

[0152] The positive electrode, separator, and negative electrode are stacked and wound in sequence to obtain an electrode assembly. The electrode assembly is placed in an outer packaging, electrolyte is added, and after processes such as encapsulation, standing, formation, and aging, a battery cell is obtained.

[0153] [Method for determining the general formula]

[0154] The general formula of cathode materials can be determined by chemical analysis.

[0155] The composition of the cathode material can be determined by inductively coupled plasma (ICP) spectroscopy, referring to standards YS / T 1006.2-2014, GB / T 23367.2-2009, or YS / T 1028.5-2015. As an example, in this embodiment, an inductively coupled plasma atomic emission spectrometer can be used for measurement. Alternatively, the content of metal elements in the sample can also be determined by gravimetric analysis and ethylenediaminetetraacetic acid (EDTA) complexometric titration.

[0156] [Method for testing Poisson's ratio]

[0157] The Poisson's ratio of the cathode material can be determined in the following way.

[0158] Surface acoustic waves are excited by directly projecting a laser beam onto the surface of the positive electrode (or positive electrode material powder); in acoustic microscopy, incident sound waves are excited by a medium striking the surface of a material. Based on classical elastic wave propagation theory, the Rayleigh wave velocity v at the surface can be calculated. R Approximate relationship with elasticity coefficient: v R =(C 11 / ρ) 1 / 2 [(2.87C 11 -4C 44 ) / 3(C 11 -4C 44 )], where: C 11 =G(E-4G) / (E-3G), C 44 =G,C 11 C 44 These are two independent elastic modulus components; ρ is the density of the thin-film material. Using different C... 11 and C 44 The optimal C value is obtained by fitting the values. 11 and C 44 The value, based on the obtained optimal C 11 and C 44 The values ​​can be used to deduce the E and G values. The Poisson's ratio of the material can be calculated using the following general formula: G = E / [2(1+S)], where: tensile modulus E (or Young's modulus), shear modulus G, and Poisson's ratio S describe the elastic behavior of the material.

[0159] [Testing the upper limit of the operating voltage of a single battery cell]

[0160] Cyclic voltammetry was used to determine the voltage range during the test, while keeping the current constant at 0.1C. The voltage range-current relationship was obtained for different voltage ranges. The upper limit voltage of the voltage range with the sudden change is the upper limit voltage of the battery cell.

[0161] [Cycle life testing of individual battery cells]

[0162] Using a constant current charge-discharge instrument, the battery was charged and discharged at 25°C under 1C / 1C conditions to test the number of cycles to reach 80% SOH state.

[0163] [Volume Energy Density Test]

[0164] At 25°C, the battery cell is charged at a constant current of 0.33C to 4.35V, then charged at a constant voltage of 4.35V until the current is less than 0.05C, and then discharged at 0.33C to 2.8V to obtain the discharge energy E; the dimensions of the battery cell are measured using the three-coordinate method (which can be measured using a three-coordinate measuring machine), and the volume V is calculated.

[0165] Volumetric energy density K = E / V.

[0166] Table 1 shows the experimental results of each embodiment and comparative example. Specific data can be found in Table 1.

[0167]

[0168]

[0169] The upper limit of the operating voltage of a single battery cell is related to the stability of the cathode material. Higher stability of the cathode material is conducive to achieving a higher upper limit of voltage for the battery cell, which in turn helps to achieve a higher energy density for the battery cell.

[0170] Based on Examples 1-23 and Comparative Example 2, and based on Examples 24 and Comparative Example 1, it can be seen that by doping with ions whose ionic radii are larger than those of lithium ions, such as sodium ions, potassium ions, cesium ions, and rubidium ions, it is beneficial to increase the upper limit of the operating voltage of a single battery cell, and also beneficial to increase the cycle life of the single battery cell.

[0171] As shown in Examples 1-7, setting the value of x appropriately is beneficial to achieving the negative Poisson's ratio characteristic of the cathode material, thereby allowing for a larger upper voltage limit for the applicable battery cell; at the same time, a smaller value of y can achieve a larger upper voltage limit.

[0172] As shown in Examples 8-13, by reasonably setting the ratio of the three elements Ni, Co, and Mn, it is beneficial to balance the energy density, upper limit of operating voltage, and cycle life of the battery cell.

[0173] As shown in Examples 1 and 24-25, adding Al to the cathode material is beneficial to improving the stability of the cathode material, thereby helping to increase the upper limit of the battery cell's operating voltage and cycle life.

[0174] As shown in Examples 14-20, the cathode material can be doped with a variety of different ions. For example, sodium ions, potassium ions, cesium ions, rubidium ions, or a combination of the above ions can be doped to increase the upper limit of the operating voltage of the battery cell.

[0175] As shown in Examples 21-23, the total content of lithium ions and doped sodium ions increases, and the content of lithium ions also increases accordingly, which is beneficial to further improve the energy density and cycle performance of the battery cell.

[0176] It should be noted that this application is not limited to the above-described embodiments. The above embodiments are merely examples, and any embodiments with the same structure and effect as the technical concept within the scope of this application are included in the technical scope of this application. Furthermore, various modifications that can be conceived by those skilled in the art to the embodiments, and other ways of constructing by combining some of the constituent elements of the embodiments, without departing from the spirit of this application, are also included in the scope of this application.

Claims

1. A positive electrode material, characterized in that, The cathode material comprises a layered lithium-containing metal oxide, the general formula of which is Li. a L x Ni b Co c Mn d M (1-b-c-d) O e N f Wherein, L ions are cations with radii larger than that of Li ions, M includes at least one of Mg, Zr, Al, B, Ta, Mo, W, Nb, Sb, and La, N includes at least one of F, S, and P, and 0 <a<2,0≤b<1,0≤c<1,0≤d<1,0<b+c+d≤1,0<e≤2,0≤f<2,0<x≤0.8。 2. The cathode material according to claim 1, characterized in that, 0.001≤x≤0.5。 3. The cathode material according to claim 2, characterized in that, 0.001≤x≤0.1。 4. The cathode material according to claim 1, characterized in that, 0＜c＜0.5。 5. The positive electrode material according to claim 1, characterized in that, 0.3≤b≤0.96。 6. The cathode material according to claim 1, characterized in that, 0<d≤0.3。 7. The cathode material according to claim 1, characterized in that, The L ions occupy at least a portion of the lithium sites in the layered lithium-containing metal oxide, and the Li ions are located at the lithium sites in the layered lithium-containing metal oxide.

8. The cathode material according to any one of claims 1-6, characterized in that, The L-ion element includes at least one of the following: alkali metal elements other than lithium, alkaline earth metal elements, transition metal elements, and other main group metal elements.

9. The cathode material according to claim 8, characterized in that, The alkali metal element includes at least one of Na, K, Rb, and Cs; The alkaline earth metal element includes at least one of Mg, Ca, and Sr; The transition metal element includes Y; Other metallic elements in the main group include Bi.

10. The cathode material according to any one of claims 1-6, characterized in that, The operating voltage V of the positive electrode material satisfies: V=kx, where 0 <k<100。 11. The cathode material according to any one of claims 1-6, characterized in that, The Poisson's ratio S of the positive electrode material is less than 0.

12. The cathode material according to claim 11, characterized in that, The Poisson's ratio S of the cathode material satisfies: -2 <S<0。 13. The cathode material according to claim 12, characterized in that, -0.2≤S≤-0.05。 14. The cathode material according to claim 12, characterized in that, The operating voltage V of the positive electrode material satisfies: V = -TS, where 0 <T<100。 15. A positive electrode plate, characterized in that, Includes the cathode material as described in any one of claims 1-14.

16. A single battery cell, characterized in that, Including the positive electrode sheet as described in claim 15.

17. The battery cell according to claim 16, characterized in that, The operating voltage of the battery cell is 2V~5V.

18. The battery cell according to claim 17, characterized in that, The operating voltage of the battery cell is 4.4V~5V.

19. A battery, characterized in that, Includes the battery cell as described in any one of claims 16-18.

20. An electrical appliance, characterized in that, Includes the battery as described in claim 19.

Images