Composite cathode material, preparation method thereof, cathode, battery and battery application

Abstract

The application discloses a composite positive electrode material and a preparation method thereof, a positive electrode, a battery and a battery application. The composite positive electrode material comprises a core containing a lithium-rich positive electrode material and a coating layer coating the core, and the coating layer contains an ABO3 perovskite, wherein A in the ABO3 contains at least one of La and Sr, and B contains at least one of Fe, Ti, Mo, Ga, Ru, Zr, Ir and Co. The coating layer contained in the composite positive electrode material constitutes an oxygen buffer layer, significantly reduces oxygen release of the lithium-rich positive electrode material in the core, improves the stability of the crystal structure of the lithium-rich positive electrode material, and obviously improves the cycle performance of the composite positive electrode material. In addition, the capacity is high, and the stability of the interface with electrolyte is good. The positive electrode and the battery both contain the composite positive electrode material.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of batteries, and particularly relates to a composite positive electrode material, a preparation method thereof, a positive electrode, a battery and a battery application. BACKGROUND

[0002] Lithium ion batteries are rapidly popularized in the fields of electric vehicles, 3C electronic products and energy storage devices due to their high energy density, small self-discharge and other advantages. With the popularization of the application of lithium batteries, the requirements for the electrochemical performance of lithium batteries, such as cycle performance, are also getting higher and higher.

[0003] The positive electrode material of a lithium ion battery has an important influence on the electrochemical performance of the battery. For example, a lithium-rich positive electrode material not only endows the battery with a high energy density, but also has an important influence on the cycle performance and safety performance of the battery. The oxygen on the surface of the lithium-rich positive electrode material is easy to escape from the lattice position, which causes the instability of the crystal framework, thereby causing the capacity attenuation of the lithium-rich positive electrode material and reducing the cycle performance of the battery. Moreover, the escaped oxygen entering the electrolyte will cause the electrolyte to have a side reaction, such as gas production, thereby reducing the safety performance of the battery. SUMMARY

[0004] In view of the above problems, the application provides a composite positive electrode material, a preparation method thereof, a positive electrode and a battery, to solve the technical problems of the existing lithium-rich positive electrode material causing the cycle performance of the battery to decrease and gas production due to oxygen release.

[0005] In a first aspect, the embodiments of the application provide a composite positive electrode material. The composite positive electrode material of the application comprises a core and a coating layer covering the core, the core contains a lithium-rich positive electrode material, and the coating layer contains an ABO3 perovskite, wherein A includes at least one element of La and Sr, and B includes at least one element of Fe, Ti, Mo, Ga, Ru, Zr, Ir and Co.

[0006] The core material in the embodiments of the application includes a lithium-rich positive electrode material, which has a high specific capacity. The coating layer contains a specific type of ABO3 perovskite, which can form an oxygen buffer layer, thereby significantly reducing the oxygen release phenomenon of the lithium-rich positive electrode material in the core, effectively alleviating the capacity attenuation of the lithium-rich positive electrode material, improving the stability of the crystal structure of the lithium-rich positive electrode material, and significantly improving the cycle performance of the composite positive electrode material. The coating layer containing the above type of ABO3 perovskite itself has chemical stability, and it reduces the amount of oxygen escaping from the composite positive electrode material into the electrolyte, effectively improves the stability of the interface between the positive electrode containing the composite positive electrode material and the electrolyte, and reduces the gas production phenomenon of the positive electrode.

[0007] In some embodiments, the ABO3 perovskite includes at least one of LaFeO3, LaTiO3, LaMoO3, LaGaO3, LaRuO3, SrTiO3, SrZrO3, LaIrO3, and LaCoO3. By selecting the above ABO3 perovskite as the coating material, the oxygen release alleviating effect of the coating layer can be improved, and the stability of the crystal structure of the lithium-rich cathode material can be further improved, so that the capacity attenuation of the lithium-rich cathode material in the core can be further alleviated. Moreover, the ABO3 perovskite can further improve the stability of the interface between the ABO3 perovskite and the electrolyte.

[0008] In some embodiments, the mass ratio of the ABO3 perovskite to the core is (0.2-0.8):100, and optionally (0.25-0.7):100.

[0009] In some embodiments, the total content of the A, B elements in the ABO3 perovskite in the composite cathode material is 800-5400 ppm, and optionally 1200-5000 ppm.

[0010] By selecting and controlling the content of the ABO3 perovskite in the composite cathode material in the range, the oxygen release alleviating effect between the ABO3 perovskite and the lithium-rich cathode material in the core can be improved, so that the stability of the crystal structure of the lithium-rich cathode material can be further improved, and the cycle performance of the composite cathode material can be significantly improved. Moreover, the ABO3 perovskite in the range can also effectively adjust the thickness of the coating layer and the stability of the interface with the electrolyte, and reduce the gas production of the cathode.

[0011] In some embodiments, the thickness of the coating layer is 0.05-1 μm, and optionally 0.1-0.4 μm.

[0012] By selecting and controlling the thickness of the coating layer in the range, the content of the ABO3 perovskite in the composite cathode material can be adjusted, so that the oxygen release alleviating effect between the ABO3 perovskite and the lithium-rich cathode material in the core can be further improved, the stability of the crystal structure of the lithium-rich cathode material can be improved, and the stability of the interface with the electrolyte can be improved. At the same time, the high capacity of the composite cathode material can also be considered.

[0013] In some embodiments, the lithium-rich cathode material includes a lithium-rich manganese-based cathode material, and the lithium-rich manganese-based cathode material is Li[Li x Ni a Co b Mn c M d ]O2, wherein x+a+b+c+d=1, x>0, a+b+c+d<1, 0<b<0.1, and M includes at least one of Mg, Nb, Cr, Ce, Fe, Ta, Al, V, Ti, Zr, Sn, and Mo.

[0014] The lithium-rich manganese-based positive electrode material shown in the structural formula has a high gram capacity, so that the composite positive electrode material has a high gram capacity, and the above-mentioned type of ABO3 perovskite in the coating layer can play a synergistic effect in relieving oxygen evolution, further relieving the oxygen evolution phenomenon of the composite positive electrode material, thereby further relieving the capacity attenuation of the lithium-rich positive electrode material to improve its cycle performance.

[0015] In some embodiments, the core has a Dv50 particle size of 5-11 μm, and optionally 6-8 μm.

[0016] The core with the particle size in the range not only increases the content ratio of the lithium-rich positive electrode material in the composite positive electrode material, and increases the gram capacity of the composite positive electrode material. Moreover, the particle size range of the core together with the thickness range of the above-mentioned coating layer makes the particle size of the composite positive electrode material in a certain range, improving the performance of the composite positive electrode material including the tap density. At the same time, the core with the particle size in the range can match the content of the perovskite in the coating layer with the thickness range, so as to improve the oxygen buffer layer effect of the coating layer on the basis of the relatively high gram capacity of the composite positive electrode material, further inhibit the oxygen evolution effect of the lithium-rich positive electrode material, thereby further relieve the capacity attenuation of the lithium-rich positive electrode material, and further improve the cycle performance of the composite positive electrode material and the stability of the interface with the electrolyte.

[0017] In some embodiments, the composite positive electrode material has at least one of the following (1) to (4):

[0018] (1) the dislocation density is 1.55×10 11 -3.5×10 11 m / m -3 , and optionally 1.8×10 11 -3.2×10 11 m / m -3 ;

[0019] (2) the microstress is 0.3-3.0%, and optionally 0.3-1.0%;

[0020] (3) the specific surface area BET is 1.2-2.5 m 2 / g, and optionally 1.35-2.3 m 2 / g;

[0021] (4) the Dv50 particle size is 6.5-11 μm, and optionally 7-10.5 μm.

[0022] The dislocation density of the composite positive electrode material is in the above range, which can relatively obviously reduce the stacking faults, thereby improving the voltage decay problem of the composite positive electrode material in the battery cycle process and improving the voltage stability of the composite positive electrode material. The micro stress of the composite positive electrode material is in the above range, which can obviously relieve the stress accumulation phenomenon of the composite positive electrode material particles in the charge and discharge cycle process, thereby improving the stability of the particle structure of the composite positive electrode material. The specific surface area of the composite positive electrode material is in the above range, which can relatively improve the stability of the contact interface between the composite positive electrode material and the electrolyte, reduce the side reaction of the contact interface, and thereby obviously improve the long-term performance of the composite positive electrode material including the cycle performance. The Dv50 of the composite positive electrode material is in the above range, which can improve the compaction density and structural stability of the composite positive electrode material and other electrochemical performances including the initial reversible capacity.

[0023] In a second aspect, the embodiments of the present application provide a preparation method of a composite positive electrode material. The preparation method of the composite positive electrode material includes the following steps:

[0024] mixing the positive electrode material particles with ABO3 perovskite precursors to obtain a mixture;

[0025] sintering the mixture to form a coating layer containing ABO3 perovskite on the surface of the positive electrode material particles to obtain a composite positive electrode material;

[0026] In the preparation method of the composite positive electrode material, the positive electrode material particles contain a lithium-rich manganese-based positive electrode material, A in the ABO3 includes at least one element of La and Sr, and B includes at least one element of Fe, Ti, Mo, Ga, Ru, Zr, Ir and Co.

[0027] The preparation method of the composite positive electrode material in the embodiments of the present application uses ABO3 perovskite precursors as raw materials to directly form a coating layer containing ABO3 perovskite on the surface of the positive electrode material particles containing a lithium-rich positive electrode material, thereby generating the composite positive electrode material in the embodiments of the present application with the core-shell structure as described above. In addition, the conditions for forming the coating layer on the surface of the positive electrode material particles in the preparation method of the composite positive electrode material in the embodiments of the present application are controllable, so that the prepared composite positive electrode material has stable performance and high efficiency, and is suitable for industrial large-scale production and application.

[0028] In some embodiments, the ABO3 perovskite precursor includes at least one perovskite precursor of LaFeO3, LaTiO3, LaMoO3, LaGaO3, LaRuO3, SrTiO3, SrZrO3, LaIrO3 and LaCoO3.

[0029] By mixing the positive electrode material particles and the ABO3 perovskite precursor in the range of the ratio, the thickness of the generated coating layer can be controlled in the range of 0.05-1 μm, and the total content of the A and B elements in the ABO3 perovskite in the composite positive electrode material can be controlled to be 1000-5000 ppm. Meanwhile, the ABO3 perovskite precursor is selected and controlled to improve the effect of the coating layer as an oxygen buffer layer, and to further reduce the oxygen release of the lithium-rich positive electrode material in the core and improve the stability of the interface between the composite positive electrode material and the electrolyte.

[0030] In some embodiments, the sintering process includes at least one of the following (1) to (3):

[0031] (1) the sintering temperature is 500-750°C, and can be 500-650°C;

[0032] (2) the temperature is raised to the sintering temperature at a temperature raising rate of 2-5°C / min;

[0033] (3) when the sintering temperature is 500-650°C, the sintering time is 6-10h.

[0034] The sintering temperature in the range can make the ABO3 perovskite precursor completely sintered and form a coating layer containing the ABO3 perovskite to coat the positive electrode material particles. Controlling the temperature raising rate in the range can effectively regulate the growth of the ABO3 perovskite crystals, so that the generated coating layer containing the ABO3 perovskite can more effectively play the role of an oxygen buffer layer, further reduce the oxygen release of the lithium-rich positive electrode material in the core, and improve the stability of the interface between the composite positive electrode material and the electrolyte.

[0035] In a third aspect, the embodiments of the present application provide a positive electrode. The positive electrode of the embodiments of the present application contains the composite positive electrode material of the embodiments of the present application or is prepared by the preparation method of the composite positive electrode material of the embodiments of the present application.

[0036] The positive electrode of the embodiments of the present application contains the composite positive electrode material of the embodiments of the present application in the active layer, so that it not only has high energy density, but also has good cycle performance, good stability of the interface with the electrolyte, and can effectively reduce the gas production.

[0037] In a fourth aspect, the embodiments of the present application provide a battery. The battery of the embodiments of the present application includes the positive electrode of the embodiments of the present application.

[0038] Since the battery of the embodiments of the present application contains the positive electrode of the embodiments of the present application, the battery of the embodiments of the present application has good cycle performance on the basis of high energy density and high electrochemical performance, and has low gas production and relatively high safety.

[0039] In a fifth aspect, the embodiments of the present application provide a power consuming device. The power consuming device of the embodiments of the present application comprises the battery of the embodiments of the present application.

[0040] The power consuming device of the embodiments of the present application has a long standby or endurance time and is safe to use.

[0041] The above description is only a summary of the technical solutions of the present application. In order to enable one of ordinary skill in the art to better understand the technical means of the present application and implement the same according to the contents of the specification, and in order to enable the above and other purposes, characteristics and advantages of the present application to be more apparent and understandable, the following detailed description of the embodiments of the present application is provided. BRIEF DESCRIPTION OF DRAWINGS

[0042] Various other advantages and benefits will become apparent to those of ordinary skill in the art upon reading the following detailed description of the preferred embodiments. The accompanying drawings are included to provide a better understanding of the preferred embodiments, and are not to be considered as limiting of the present application. Moreover, in the drawings, like reference numerals denote same or similar components. In the drawings:

[0043] Figure 1 A structural schematic diagram of a composite positive electrode material of some embodiments of the present application;

[0044] Figure 2 A structural schematic diagram of a positive electrode of some embodiments of the present application;

[0045] Figure 3 Another structural schematic diagram of a positive electrode of some embodiments of the present application;

[0046] Figure 4 A structural schematic diagram of an embodiment of the battery cell of the embodiments of the present application;

[0047] Figure 5 A structural schematic diagram of an embodiment of the battery cell of the embodiments of the present application; Figure 4

[0048] Figure 6 A structural schematic diagram of an embodiment of the battery module of the embodiments of the present application;

[0049] Figure 7 A structural schematic diagram of an embodiment of the battery pack of the embodiments of the present application;

[0050] Figure 8 A structural schematic diagram of an embodiment of the battery pack of the embodiments of the present application; Figure 7

[0051] Figure 9 A structural schematic diagram of an embodiment of the power consuming device comprising the battery of the embodiments of the present application as a power supply;

[0052] The reference numerals in the detailed description are as follows: ​​

[0053] 10 - composite cathode material, 11 - core, 12 - coating layer;

[0054] 20 - cathode, 21 - current collector, 22 - active layer;

[0055] 30 - battery cell, 31 - case, 32 - electrode assembly, 33 - cover plate;

[0056] 40 - battery module;

[0057] 50 - battery pack, 51 - box, 52 - lower box. DETAILED DESCRIPTION

[0058] The embodiments of the technical solutions of the present application will be described in detail below with reference to the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solutions of the present application, and therefore only serve as examples, and cannot limit the protection scope of the present application.

[0059] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs; the terms used herein are only for the purpose of describing specific embodiments and are not intended to limit the present application; the terms "include" and "have" and any variations thereof in the specification and claims of the present application and the above description of drawings are intended to cover non-exclusive inclusion.

[0060] In the description of the embodiments of the present application, the technical terms "first", "second", etc. are only used to distinguish different objects, and cannot be understood as indicating or implying relative importance or implicitly indicating the number, specific order or primary and secondary relationship of the indicated technical features. In the description of the embodiments of the present application, the meaning of "a plurality of" is two or more, unless otherwise explicitly and specifically limited.

[0061] Reference herein to "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment can be included in at least one embodiment of the present application. The appearance of this phrase in various places in the specification does not necessarily all refer to the same embodiment, nor is it necessarily mutually exclusive or alternative to other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0062] In the description of the embodiments of the present application, the term "and / or" is only a description of the association relationship between the associated objects, which means that there can be three relationships, for example, A and / or B, which can represent the three cases of A alone, A and B together, and B alone. In addition, the character " / " in this paper generally represents a "or" relationship between the front and rear associated objects.

[0063] In the description of the embodiments of the present application, the term "a plurality of" refers to two or more (including two), and similarly, "a plurality of groups" refers to two or more groups (including two groups), and "a plurality of pieces" refers to two or more pieces (including two pieces).

[0064] In the description of the embodiments of the present application, the technical terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate the orientation or positional relationship shown in the drawings, which is only for the convenience of describing the embodiments of the present application and simplifying the description, and does not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the embodiments of the present application.

[0065] In the description of the embodiments of the present application, unless otherwise explicitly specified and limited, the technical terms "mounting", "connection", "connection", "fixing" and the like should be understood broadly, for example, it can be fixedly connected, or it can be detachably connected, or it can be integrated; it can be mechanically connected, or it can be electrically connected; it can be directly connected, or it can be indirectly connected through an intermediate medium; it can be the internal communication of two elements or the interaction relationship between two elements. For those skilled in the art, the specific meaning of the above terms in the embodiments of the present application can be understood according to the specific circumstances. With the rapid popularization of lithium batteries, especially in electric vehicles, the requirements for the cycle performance and safety of lithium batteries are also increasing.

[0066] The positive electrode is one of the important components of the battery, which contains a positive electrode active material. The positive electrode active material has an important influence on the electrochemical performance of the battery, such as the cycle performance, energy density and safety performance of the battery. With the emergence of lithium-rich positive electrode materials, the energy density of the battery is significantly improved. However, the lithium-rich positive electrode material also has certain deficiencies, such as the oxygen release phenomenon of the lithium-rich manganese-based positive electrode material in the lithium-rich positive electrode material, which specifically manifests that the oxygen on the surface of the lithium-rich positive electrode is easy to escape from the lattice position, which will cause the instability of the crystal framework, thereby causing the cycle performance of the battery to decrease.

[0067] Moreover, the escaped oxygen has high reactivity, which will reduce the stability of the electrode and electrolyte interface, such as will corrode the electrolyte at the electrode / electrolyte interface to cause unstable SEI and corresponding protons, and the protons will continue to etch the material to accelerate the progress of these adverse reactions, such as generating gas and other adverse phenomena.

[0068] In order to effectively alleviate the oxygen release phenomenon of the lithium-rich cathode material and improve the stability of the lithium-rich cathode material, it is reported that a coating layer is constructed on the surface of the lithium-rich cathode material to realize coating modification treatment of the lithium-rich cathode material. However, it is found through research that the oxygen release phenomenon of the lithium-rich cathode material with the coating structure disclosed at present is improved to some extent compared with the lithium-rich cathode material without the coating layer, but is still not ideal.

[0069] In order to further alleviate the oxygen release phenomenon of the lithium-rich cathode material and further improve the stability of the structure and electrochemical performance of the lithium-rich cathode material, through research, the application embodiment provides a composite cathode material with a coating structure. Specifically, perovskite is used as a coating layer material, and the type of the perovskite material is controlled to improve the synergistic effect between the coating layer and the lithium-rich cathode material, improve the modification effect of the coating layer on the lithium-rich cathode material, significantly alleviate the oxygen release phenomenon of the lithium-rich cathode material, and improve the crystal structure stability of the composite cathode material, thereby significantly improving the electrochemical performance of the battery, including the cycle performance.

[0070] Composite cathode material

[0071] In a first aspect, the application embodiment provides a composite cathode material. The composite cathode material of the application embodiment has a core-shell structure. In some embodiments, the structure of the composite cathode material of the application embodiment is as shown in Figure 1 The composite cathode material 10 includes a core body 11 and a coating layer 12 coating the core body 11. The core body 11 contains a lithium-rich cathode material, and the coating layer 12 contains ABO3 perovskite. In the ABO3 perovskite, A includes at least one element of La and Sr, and B includes at least one element of Fe, Ti, Mo, Ga, Ru, Zr, Ir, and Co.

[0072] The core-shell structure of the composite cathode material 10 of the application embodiment refers to the core body 11 and the shell layer coating the core body 11, that is, the coating layer 12. The coating of the core body 11 refers to the formation of a film layer of the coating layer 12 surrounding the surface of the core body 11. The core body 11 containing the lithium-rich cathode material can be understood as that the material of the core body 11 is entirely the lithium-rich cathode material. Of course, on the basis of containing the lithium-rich cathode material, other components can also be contained, such as a lithium supplement material that is beneficial to improving the capacity of the lithium-rich cathode material or an additive that can play a synergistic effect with the coating layer 12 to reduce the oxygen release of the lithium-rich cathode material. Similarly, the coating layer 12 containing the ABO3 perovskite can be understood as that the material of the coating layer 12 is entirely the ABO3 perovskite. Of course, on the basis of containing the ABO3 perovskite, other components can also be contained, such as an additive that is beneficial to playing a synergistic effect with the ABO3 perovskite to alleviate the oxygen release of the lithium-rich cathode material.

[0073] The core 11 contained in the composite cathode material 10 of the embodiment of the present application contains a lithium-rich cathode material, which gives the composite cathode material 10 a high specific capacity. A specific element is selected for A and B in the ABO3 perovskite, and the ABO3 perovskite has a relatively regular cubic perovskite structure, and the crystal symmetry is relatively high, O 2- The transport isotropy is relatively high, and therefore, the specific ABO3 perovskite can relatively well form an oxygen buffer layer in the coating layer 12. Since the coating layer 12 can play a better role as an oxygen buffer layer, the oxygen release phenomenon of the lithium-rich cathode material in the core 11 can be significantly inhibited, the stability of the crystal structure of the lithium-rich cathode material is improved, and therefore, the capacity decay of the lithium-rich cathode material is effectively alleviated, so that the cycle performance of the composite cathode material 10 can be significantly improved. Due to the oxygen release effect of the coating layer 12, the amount of oxygen escaping from the composite cathode material 10 into the electrolyte can be effectively reduced; in addition, the chemical properties of the ABO3 perovskite of the above type, such as acid resistance, are relatively stable compared to other perovskites, and the acid corrosion resistance is enhanced, such as the corrosion from the electrolyte byproduct HF. Therefore, through the combined action of the oxygen release effect of the coating layer 12 and its good chemical stability, the stability of the interface between the cathode containing the composite cathode material 10 and the electrolyte is effectively improved, and the gas generation phenomenon of the cathode is reduced.

[0074] In the embodiment, the lithium-rich cathode material contained in the core 11 of the composite cathode material 10 can include a lithium-rich manganese-based cathode material. The molecular general formula of the lithium-rich manganese-based cathode material can be represented as Li[Li x Ni a Co b Mn c M d ]O2, wherein x+a+b+c+d=1, x>0, a+b+c+d<1, 0<b<0.1, and M includes at least one of Mg, Nb, Cr, Ce, Fe, Ta, Al, V, Ti, Zr, Sn, and Mo. In an exemplary embodiment, the lithium-rich manganese-based cathode material can specifically include Li 1.2 Mn 0.48 Co 0.1 Ni 0.2 Ti 0.02 O2, Li 1.2 Mn 0.48 Co 0.1 Ni 0.2 Zr 0.02 O2, Li 1.2 Mn 0.48 Co 0.1 Ni 0.2 Mo 0.02 O2, Li 1.2 Mn 0.48 Co 0.1 Ni0.2 V 0.02 O2, etc. The lithium-rich manganese-based positive electrode material shown in the structural formula has a high gram capacity, so that the composite positive electrode material 10 has a high gram capacity, and can play a synergistic effect of alleviating oxygen evolution between the ABO3 perovskite in the coating layer 12 and the above-mentioned type, further alleviate the oxygen evolution phenomenon of the composite positive electrode material 10, and improve the cycle performance of the composite positive electrode material 10.

[0075] The core body 11 in the composite positive electrode material 10 can be regular or irregular in appearance. In the exemplary embodiment, the core body 11 can be spherical or similar spherical in appearance, and of course can also be other appearances. Moreover, the particle size and the thickness of the coating layer 12 can jointly affect the particle size of the composite positive electrode material 10. In the embodiment, the Dv50 particle size of the core body 11 can be 5-11 μm, and optionally 6-8 μm. In the exemplary embodiment, it can be 5 μm, 6 μm, 7 μm, 8 μm, 9 μm, 10 μm, 11 μm, etc. The particle size of the core body 11 is selected and controlled in the above range, which not only increases the content ratio of the lithium-rich positive electrode material in the composite positive electrode material 10 and improves the gram capacity of the composite positive electrode material 10. Moreover, the core body 11 with the particle size in the above range can match the content of the perovskite in the coating layer 12, so as to improve the oxygen buffer layer effect of the coating layer 12 on the basis of the relatively high gram capacity of the composite positive electrode material 10, and improve the oxygen evolution inhibition effect of the lithium-rich positive electrode material, thereby further alleviating the capacity attenuation of the lithium-rich positive electrode material and further improving the cycle performance and stability of the interface with the electrolyte of the composite positive electrode material 10. In addition, the particle size range of the core body 11 can also jointly regulate the particle size of the composite positive electrode material 10 with the coating layer 12. For example, the Dv50 particle size of the composite positive electrode material 10 can be 6.5-11 μm, so as to improve the performance of the composite positive electrode material 10, including the compaction density.

[0076] In the embodiments, the mass ratio of ABO3 perovskite to the core 11 in the coating layer 12 of the composite cathode material 10 in the above embodiments can be (0.2-0.8):100, or optionally (0.25-0.7):100. Typical but non-limiting ratios include 0.2:100, 0.3:100, 0.4:100, 0.5:100, 0.6:100, 0.7:100, and 0.8:100. By controlling the content of ABO3 perovskite in the composite cathode material 10 within this range, the synergistic effect of slow oxygen desorption between ABO3 perovskite and the lithium-rich cathode material in the core 11 can be improved, thereby further enhancing the stability of the lithium-rich cathode material crystal structure in the core 11 and significantly improving the cycle performance of the composite cathode material 10. Furthermore, the ABO3 perovskite content within this range can effectively regulate the thickness of the coating layer 11 and the stability of the interface with the electrode liquid, reducing the gas generation phenomenon of the positive electrode.

[0077] In the embodiments, the thickness range of the coating layer 12 can be adjusted by controlling the total content of ABO3 perovskite in the composite cathode material 10. For example, in the embodiments, the thickness of the coating layer 12 contained in the composite cathode material 10 can be controlled to be 0.05–1 μm, optionally 1–0.8 μm, and further can be 0.1–0.4 μm. In exemplary examples, typical but non-limiting thickness ranges such as 0.05–0.1 μm, 0.1–0.2 μm, 0.2–0.3 μm, 0.3–0.4 μm, 0.4–0.5 μm, 0.5–0.6 μm, 0.6–0.7 μm, 0.7–0.8 μm, 0.8–0.9 μm, and 0.9–1 μm can be used. By controlling the thickness of the coating layer 12 within this range, the content of ABO3 perovskite in the composite cathode material 10 can be adjusted. Compared to other content ranges, this improves the oxygen desorption synergistic effect between ABO3 perovskite and the lithium-rich cathode material in the core 11, enhances the stability of the lithium-rich cathode material's crystal structure, and improves the stability of the interface with the electrode liquid. As shown in Table 2 below, the relevant performance of the batteries in Examples B1 to B4 is superior to that of the batteries shown in Examples B5 and B6. Simultaneously, it also achieves a high specific capacity for the composite cathode material 10. Specifically, when the coating layer 12 contains only ABO3 perovskite, the coating layer 12 within this thickness range is formed by adjusting the content of ABO3 perovskite.

[0078] Based on the thickness of the coating layer 12 and the mass ratio range of the perovskite to the core body 11, it is detected that the total content of A and B elements in the ABO3 perovskite in the coating layer 12 of the composite cathode material 10 in each of the above embodiments in the composite cathode material 10 is 800-5400 ppm, 1000-5000 ppm, optionally 1200-5000 ppm, 1500-4500 ppm, and in the exemplary examples, it can be 1000-1500 ppm, 1500-2000 ppm, 2000-2500 ppm, 2500-3000 ppm, 3000-3500 ppm, 3500-4000 ppm, 4000-4500 ppm, 4500-5000 ppm, etc. typical but non-limiting content range. Among them, the total content of A and B elements in the composite cathode material 10 can be determined by the conventional method of element content. As an example, it can be determined by ICP emission spectrometry (inductively coupled plasma emission spectrometer), and the specific test procedure refers to the standard test method EPA 6010D-2014.

[0079] In the embodiments, based on the types of elements represented by A and B in the ABO3 perovskite contained in the coating layer 12 of the composite cathode material 10 in each of the above embodiments, the valence of A ion can be +2 or +3, and the valence of B ion can be +3 or +4; the ionic radius r A of the element represented by A can be 70 pm≤r A ≤150 pm; and the ionic radius r B of the element represented by B can be 40 pm≤r B ≤100 pm, and r A >r B . In the exemplary examples, the ABO3 perovskite can specifically include at least one of LaFeO3, LaTiO3, LaMoO3, LaGaO3, LaRuO3, SrTiO3, SrZrO3, LaIrO3, and LaCoO3. The above ABO3 perovskite has higher O 2- transport isotropy and high crystal symmetry, which can improve the oxygen buffer effect of the coating layer 12, thereby improving the relaxation oxygen effect of the coating layer 12, so as to further improve the stability of the crystal structure of the lithium-rich cathode material, thereby further relieving the capacity attenuation of the lithium-rich cathode material, thereby significantly improving the cycle performance of the composite cathode material 10. Moreover, the ABO3 perovskite of the above types has stronger acid resistance, thereby further improving the stability of the interface between the cathode containing the composite cathode material 10 and the electrolyte, and reducing the gas production phenomenon of the cathode.

[0080] Based on the core 11 and the coating layer 12 of the composite cathode material 10, the dislocation density, micro stress, specific surface area, particle size and other properties of the composite cathode material 10 can be improved by adjusting and controlling the particle size of the core 11 and the material and thickness of the coating layer 12, so as to further improve the mechanical properties such as structural strength and the electrochemical properties such as voltage stability and stability of the contact interface with the electrolyte of the composite cathode material 10.

[0081] As in the examples, the dislocation density of the composite cathode material 10 of each of the above examples can be 1.55×10 11 ~ 3.5×10 11 m / m -3 , optionally 1.8×10 11 ~ 3.2×10 11 m / m -3 , and in exemplary examples, can be 1.55×10 11 ~ 1.8×10 11 m / m -3 , 1.8×10 11 ~ 2.0×10 11 m / m -3 , 2.0×10 11 ~ 2.5×10 11 m / m -3 , 2.5×10 11 ~ 3.0×10 11 m / m -3 , 3.0×10 11 ~ 3.2×10 11 m / m -3 , 3.2×10 11 ~ 3.5×10 11 m / m -3 , and other typical but non-limiting dislocation density ranges. The dislocation density quantifies the dislocations contained in the crystal of the composite cathode material 10, specifically the total length of dislocation lines contained in the unit volume of the crystal. Controlling the dislocation density of the composite cathode material 10 within the above range can relatively significantly reduce stacking faults compared to other ranges of dislocation density, thereby relatively significantly improving the voltage decay problem of the composite cathode material during battery cycling and relatively improving the voltage stability of the composite cathode material 10.

[0082] In the embodiments, the micro stress of the composite cathode material 10 in the above embodiments can be 0.3-3.0%, optionally 0.3-1.0%, and in exemplary embodiments, can be in a typical but non-limiting micro stress range of 0.3-0.5%, 0.5-1%, 1-1.5%, 1.5-2%, 2-2.5%, 2.5-3%, etc. The micro stress refers to the stress acting between the microstructures of the composite cathode material 10, also known as micro residual stress, and specifically refers to the stress existing between the grains or in the grains of the composite cathode material 10 due to factors such as deformation, phase change, and expansion of multi-phase materials. Controlling the micro stress of the composite cathode material within the above range can significantly improve the balance between the grains or between the grains in the composite cathode material 10 compared to other ranges of micro stress, thereby significantly relieving the stress accumulation phenomenon of the composite cathode material 10 particles during the charge and discharge cycle, thereby improving the stability of the particle structure of the composite cathode material 10 and significantly reducing the secondary ball breakage phenomenon of the composite cathode material 10 caused by excessive stress.

[0083] In the embodiments, the BET specific surface area of the composite cathode material 10 in the above embodiments can be 1.2-2.5 m 2 / g, optionally 1.35-2.3 m 2 / g, and in exemplary embodiments, can be in a typical but non-limiting specific surface area range of 1.2-1.35 m 2 / g, 1.35-1.5 m 2 / g, 1.5-1.8 m 2 / g, 1.8-2 m 2 / g, 2-2.3 m 2 / g, 2.2-2.5 m 2 / g, etc. The BET specific surface area refers to the total area per unit mass of the composite cathode material 10. Controlling the specific surface area of the composite cathode material within the above range can appropriately increase the contact area of the composite cathode material 10 particles with the electrolyte, improve the stability of the contact interface between the composite cathode material 10 and the electrolyte on the basis of fully utilizing the high capacity of the composite cathode material 10, reduce the side reactions at the contact interface, and thereby significantly improve the long-term performance of the composite cathode material 10, including the cycle performance.

[0084] In the embodiment, the composite cathode material 10 of each of the above embodiments can control the particle size of the core 11 and the thickness of the coating layer 12, etc. of the composite cathode material 10, so that the Dv50 particle size of the composite cathode material 10 can be 6.5-11 μm, and can be selected to be 7-10.5 μm, and in the exemplary embodiment, it can be a typical but non-limiting particle size range of 6.5 μm, 7 μm, 8 μm, 9 μm, 10 μm, 11 μm, etc. The Dv50 particle size of the composite cathode material is controlled within the above range, and compared with other particle sizes, the compaction density of the composite cathode material 10 particles can be improved, and the structural stability of the composite cathode material 10 particles can be improved, and the first reversible capacity and other electrochemical properties of the composite cathode material 10 can be improved at the same time.

[0085] Method for preparing composite cathode material

[0086] In a second aspect, the embodiments of the present application provide a method for preparing the composite cathode material of the above embodiments. The composite cathode material of the embodiments of the present application includes the following steps:

[0087] Step S10: mixing and processing the cathode material particles and the ABO3 perovskite precursor to obtain a mixture;

[0088] Step S20: sintering the mixture to form a coating layer containing ABO3 perovskite on the surface of the cathode material particles to obtain a composite cathode material.

[0089] In the step S10, the cathode material particles are the core 11 contained in the composite cathode material 10 of the above embodiments of the present application as shown in Figure 1 Therefore, the cathode material particles in step S10 contain a lithium-rich manganese-based cathode material. The ABO3 perovskite precursor in step S10 is to form the ABO3 perovskite in the coating layer 12 contained in the composite cathode material 10 of the above embodiments of the present application, and specifically, A in ABO3 includes at least one element of La and Sr, and B includes at least one element of Fe, Ti, Mo, Ga, Ru, Zr, Ir and Co. Therefore, the coating layer formed on the surface of the cathode material particles in step S20 is the coating layer 12 contained in the composite cathode material 10 of the above embodiments of the present application as shown in Figure 1

[0090] ​Thus, the preparation method of the composite cathode material in this application uses ABO3 perovskite precursor as raw material to directly form an ABO3 perovskite-containing coating layer on the surface of cathode material particles containing lithium-rich cathode material, thereby generating the composite cathode material 10 of this application with the core-shell structure described above. Therefore, the cathode material particles, as the core, endow the prepared composite cathode material with high electrochemical performance, including specific capacity. The formed coating layer effectively constitutes an oxygen buffer layer, which can suppress the oxygen release phenomenon of lithium-rich cathode material in the core, thereby effectively improving the crystal structure stability of lithium-rich cathode material in the core, alleviating the capacity decay of lithium-rich cathode material, and significantly improving the cycle performance of composite cathode material. Moreover, the formed coating layer has stable chemical properties, effectively enhancing the stability of the interface between the prepared composite cathode material and the electrolyte, and reducing gas generation. In addition, the conditions for forming the coating layer on the surface of cathode material particles in the preparation method of the composite cathode material in this application are controllable, making the prepared composite cathode material stable and efficient, suitable for large-scale industrial production and application.

[0091] Step 10:

[0092] Because the positive electrode material particles in step 10 are as follows Figure 1 The composite cathode material 10 shown in the above-described embodiment contains a core 11. Therefore, the cathode material particles include the same components and particle size as the core 11 of the composite cathode material 10 described above. Similarly, the ABO3 perovskite precursor in step 10 is the perovskite precursor that forms the ABO3 perovskite in the coating layer 12 of the composite cathode material 10 described above. Therefore, the specific ABO3 perovskite precursor can be selected and controlled according to the type of ABO3 perovskite. Specifically, the ABO3 perovskite precursor can be selected and controlled according to the type of ABO3 perovskite in the coating layer 12 of the composite cathode material 10 described above.

[0093] Furthermore, the cathode material particles can be cathode material particles prepared according to conventional cathode material preparation methods, or cathode material particles prepared by modifying conventional cathode material preparation methods. For example, in the demonstration example, when the cathode material particles are lithium-rich cathode materials, specifically lithium-rich manganese-based material particles, they can be prepared according to conventional methods for preparing lithium-rich cathode materials, specifically lithium-rich manganese-based materials.

[0094] In this embodiment, the ABO3 perovskite precursor may include at least one perovskite precursor selected from LaFeO3, LaTiO3, LaMoO3, LaGaO3, LaRuO3, SrTiO3, SrZrO3, LaIrO3, and LaCoO3. Using these precursors, the perovskite can be sintered during the sintering process in step S30 to generate the corresponding ABO3 perovskite described above.

[0095] In the embodiment, the mixing treatment of the positive electrode material particles and the ABO3 perovskite precursor can be dry mixing treatment or solution mixing treatment.

[0096] The dry mixing treatment can be mixing treatment of the positive electrode material particles and the powder of the ABO3 perovskite precursor without solvent. In the embodiment, the dry mixing treatment can be stirring or ball milling treatment of the mixture including the positive electrode material particles and the ABO3 perovskite precursor.

[0097] The solution mixing treatment is relative to the dry mixing treatment. In the embodiment, the ABO3 perovskite precursor is prepared into a solution and mixed with the positive electrode material particles to form a mixture slurry, and then the solvent is removed by drying treatment, so that the ABO3 perovskite precursor can form a precursor coating layer to coat the surface of the positive electrode material particles. The ABO3 perovskite precursor and the positive electrode material particles can also be mixed with the solvent to prepare a mixture slurry, and then the solvent is removed by drying treatment, so that the ABO3 perovskite precursor can form a precursor coating layer to coat the surface of the positive electrode material particles.

[0098] In the mixing treatment process of step S10, the mass content and thickness of the coating layer generated in step S20 can be adjusted by controlling the mixing ratio of the positive electrode material particles and the ABO3 perovskite precursor. In the embodiment, the mass ratio of the positive electrode material particles and the ABO3 perovskite is controlled to satisfy the mass ratio of the ABO3 perovskite in the core 11 and the coating layer 12 of the composite positive electrode material 10 in the above embodiment, which is 100:(0.2-0.8), or optionally 100:(0.25-0.7). That is, in step S10, the positive electrode material particles and the ABO3 perovskite precursor are mixed at a mass ratio of 100:(0.2-0.8), or optionally 100:(0.25-0.7). By mixing at this ratio, the thickness of the coating layer generated in step S20 can be controlled to be 0.05-1 μm as described above, and the total content of A and B elements in the ABO3 perovskite in the composite positive electrode material can be controlled to be 1000-5000 ppm. This can improve the effect of the coating layer as an oxygen buffer layer, further reduce the oxygen release phenomenon of the lithium-rich positive electrode material in the core, and improve the stability of the interface between the composite positive electrode material and the electrolyte.

[0099] Step 20:

[0100] During the sintering process in step 20, the ABO3 perovskite precursor will be sintered to generate the ABO3 perovskite in the coating layer 12 contained in the composite cathode material 10 of the above application embodiment, and can form cathode material particles coated with a coating layer containing ABO3 perovskite.

[0101] In this embodiment, the sintering temperature can be controlled between 500 and 650°C. This temperature range allows the ABO3 perovskite precursor to be completely sintered, forming an ABO3 perovskite-containing coating layer that coats the cathode material particles. At this sintering temperature, the sintering time should be sufficient; for example, in this embodiment, when the sintering temperature is 500–650°C, the sintering time is 6–10 hours.

[0102] In this embodiment, the sintering process can be controlled to reach the sintering temperature at a heating rate of 2–5 °C / min. Controlling this heating rate within this range effectively regulates the growth of ABO3 perovskite crystals, enhances the oxygen buffering effect of the ABO3-containing perovskite coating layer, further reduces oxygen release from the lithium-rich cathode material in the core, and improves the stability of the interface between the composite cathode material and the electrolyte.

[0103] positive electrode

[0104] Thirdly, embodiments of this application provide a positive electrode. In some embodiments, such as... Figure 2 and Figure 3 As shown, the positive electrode 20 of this application embodiment includes a current collector 21 and an active layer 22. The active layer 22 is bonded to the current collector 21. In the positive electrode 20 of this application embodiment, the positive electrode active material contained in the active layer 22 includes the composite positive electrode material 10 of the above-described application embodiment.

[0105] Since the positive active material contained in the active layer 22 of the positive electrode 20 in this application embodiment includes the composite positive electrode material 10 in the above application embodiment, the positive electrode 20 in this application embodiment not only has high energy density, but also has good cycle performance. Its interface stability with the electrolyte is good, which can effectively reduce gas generation.

[0106] In this embodiment, the current collector 21 included in the positive electrode 20 refers to a structure or component used for collecting current. In the embodiments, the current collector 21 included in the positive electrode 20 includes, but is not limited to, metal current collectors, carbon current collectors, conductive resin current collectors, and composite current collectors of metal and resin, more specifically, copper, nickel, titanium, iron and their respective alloys, stainless steel, carbon fiber, carbon nanotubes (CNTs), graphite, etc. In the embodiments, the current collector 21 can also be a dense film layer or a porous film layer.

[0107] The active layer 22 contained in the positive electrode 20 of the embodiment refers to a film layer containing a positive electrode active material. In the embodiment, the active layer 22 contained in the positive electrode 20 of the embodiment can be laminated on the surface of the current collector 21 in combination with the current collector 21. When the surface layer of the current collector 21 contains a porous structure or the current collector 21 itself is a porous structure, the active layer 22 can be at least partially embedded into the current collector 21.

[0108] In the embodiment, when the active layer 22 is laminated on the surface of the current collector 21, the active layer 22 can be combined on one surface of the current collector 21, as shown in FIG. 2A. When the current collector 21 contains two opposite surfaces, that is, the current collector 21 is a film structure, the active layer 22 can be combined on the two opposite surfaces of the current collector 21, as shown in FIG. 2B. Figure 2 Figure 3

[0109] In the embodiment, the active layer 22 contained in the positive electrode 20 of the embodiment contains the composite positive electrode material 10 of the embodiment of the application, and further contains necessary components such as a positive electrode active material and other components. The other components can include a binder or can further contain a conductive agent, other additives, and the like.

[0110] In the embodiment, when the active layer 22 contains a binder, the binder can include one or more of an oil-soluble binder, a water-soluble binder, an emulsion-type binder, and the like. In an exemplary embodiment, the oil-soluble binder can include one or more of polyvinylidene fluoride, polyimide, polytetrafluoroethylene, polybutyl acrylate, polyacrylonitrile, and the like; in an exemplary embodiment, the water-soluble binder can include one or more of carboxymethyl cellulose, carboxymethyl cellulose salt, polyacrylic acid, polyacrylic acid salt, polyvinyl alcohol, sodium alginate, cyclodextrin, and the like; in an exemplary embodiment, the emulsion-type binder includes one or more of butadiene-styrene rubber, vinyl acetate resin, acrylic resin, chlorinated rubber, and the like.

[0111] In the embodiment, when the active layer 22 contains a conductive agent, the conductive agent can include one or more of acetylene black (SP), carbon nanotube, conductive carbon black (super-P), ketjen black, carbon fiber, graphene, and the like.

[0112] In the embodiment, when the active layer 22 contains other additives, the additives can include, but are not limited to, functional components such as lithium supplement additives.

[0113] The positive electrode active material, the binder, and the conductive agent, and the like can be selected according to the application or production requirements of the positive electrode 20.

[0114] ​​The positive electrode 20 of the embodiment of the present application can be prepared according to a conventional method for preparing a positive electrode, which can include the following steps: preparing a slurry containing the above composite positive electrode material and a binder and a solvent or further containing an electrically conductive agent, other additives, etc., and performing film processing (wet film) of the slurry on the current collector 21; then performing drying processing to volatilize the solvent, thereby drying the wet film; and then performing roll processing on the dried film layer to form the active layer 22, thereby obtaining the positive electrode 20.

[0115] Battery

[0116] In a fourth aspect, the embodiment of the present application further provides a battery. The battery of the embodiment of the present application includes a positive electrode and a negative electrode, wherein the positive electrode is the above positive electrode 20 of the embodiment of the present application.

[0117] Since the battery of the embodiment of the present application contains the above positive electrode 20 of the embodiment of the present application, the battery of the embodiment of the present application has good cycle performance and low gas production and relatively high safety on the basis of high energy density and other electrochemical properties.

[0118] In the embodiment, the negative electrode contained in the battery of the embodiment of the present application can be a conventional negative electrode, which, in the embodiment, can be a negative electrode matched with the positive electrode 20 of the embodiment of the present application.

[0119] Of course, the battery of the embodiment of the present application can further include other necessary components or auxiliary components in addition to the above electrodes and other components. For example, when the battery of the embodiment of the present application is an ion battery, the battery of the embodiment of the present application includes a separator, an electrolyte, and other constituent components or parts.

[0120] In the embodiment, the above battery of each embodiment can include any one of a battery monomer, a battery module, and a battery pack.

[0121] The battery monomer refers to a battery shell and an electrode assembly (also referred to as a bare cell) packaged in the battery shell. The shape of the battery monomer is not particularly limited, and it can be cylindrical, square, or any other shape. In an exemplary embodiment, the battery monomer can be a square-structure battery monomer 30 as shown in FIG. 1. Figure 4

[0122] In some embodiments, as shown in FIG. 2, the battery module 40 can include a plurality of battery monomers 30, a plurality of separators 41, and a plurality of electrolytes 42. Figure 5 ​As shown, the outer package of the battery cell 30 can include a housing 31 and a cover plate 33. The housing 31 can include a bottom plate and side plates connected to the bottom plate, which enclose a receiving cavity. The housing 31 has an opening communicating with the receiving cavity, and the cover plate 33 is used to cover the opening to seal the receiving cavity. The positive electrode 20, the separator and the negative electrode contained in the battery cell 30 of the embodiment can form an electrode assembly 32 through a winding process and / or a stacking process. The electrode assembly 32 is packaged in the receiving cavity. The electrolyte is impregnated in the electrode assembly 32. The number of the electrode assembly 32 contained in the battery cell 30 can be one or more, which can be adjusted according to actual needs.

[0123] In some embodiments, the battery cell 30 can be prepared by assembling the positive electrode 20, the separator and the negative electrode and the electrolyte. For example, the positive electrode 20, the separator and the negative electrode can be formed into an electrode assembly 32 through a winding process or a stacking process, the electrode assembly 32 is placed in an outer package, and the electrolyte is injected after drying. After vacuum packaging, standing, formation, shaping and other processes, the battery cell 30 is obtained. Since the battery cell 30 contains the positive electrode 20 of the above embodiment.

[0124] In the embodiment, when the battery of the embodiment is a battery module, the battery module refers to being assembled from the battery cell 30, that is, can contain a plurality of battery cells 30, and the specific number can be adjusted according to the application and capacity of the battery module.

[0125] In some embodiments, Figure 6 FIG. 1 is a schematic diagram of a battery module 40 as an example. As shown in FIG. 1, the battery module 40 can include a plurality of battery cells 30. Figure 6 As shown in the battery module 40, the plurality of battery cells 30 can be arranged in sequence along the length direction of the battery module 40. Of course, other arbitrary arrangements can also be used. Further, the plurality of battery cells 30 can be fixed by fasteners.

[0126] Optionally, the battery module 40 can further include a housing having a receiving space, and the plurality of battery cells 30 are received in the receiving space.

[0127] The battery pack refers to being assembled from the battery cell 30, that is, can contain a plurality of battery cells 30, wherein the plurality of battery cells 30 can be assembled into the battery module 40. The specific number of the battery cells 30 or the battery module 40 contained in the battery pack can be adjusted according to the application and capacity of the battery pack.

[0128] As shown in the embodiment, Figure 7 and Figure 8is a schematic diagram of a battery pack 50 as an example. In the battery pack 50, a battery case and a plurality of battery modules 40 disposed in the battery case can be included. The battery case includes an upper case 51 and a lower case 52, and the upper case 51 is used to cover the lower case 52 and forms a closed space for accommodating the battery modules 40. The plurality of battery modules 40 can be arranged in the battery case in any manner.

[0129] Electric device

[0130] In a fifth aspect, the embodiments of the present application further provide an electric device. The electric device of the embodiments of the present application includes a power supply unit or an energy storage unit, and of course can further include other auxiliary components or necessary components. The power supply unit or the energy storage unit contains the battery of the above embodiments of the present application. The battery contained in the power supply unit or the energy storage unit can be one or more. When there are multiple, the multiple batteries can form a battery module or a battery pack. Since the electric device of the embodiments of the present application contains the battery of the above embodiments of the present application, the power supply unit or the energy storage unit of the electric device of the embodiments of the present application has high energy density, good cycle performance, long service life, and high safety, and the standby or endurance time of the electric device of the embodiments of the present application is long, and the use safety is high.

[0131] Figure 9 is a schematic diagram of an electric device as an example. The electric device is a pure electric vehicle, a hybrid electric vehicle, or a plug-in hybrid electric vehicle, etc. In order to meet the demand of the electric device for high power and high energy density, a battery pack or a battery module can be used.

[0132] The electric device as another example can be a mobile phone, a tablet computer, a notebook computer, etc. The electric device usually requires thin and light, and a secondary battery can be used as a power supply.

[0133] In the embodiments, when the electric device includes an energy storage unit, the electric device can be an energy storage device, and the energy storage device includes an energy storage unit, and of course can further include other auxiliary components or necessary components. The energy storage unit contains the battery of the above embodiments of the present application. The battery contained in the energy storage unit can be one or more. When there are multiple, the multiple batteries can form a battery module or a battery pack. Since the energy storage device of the embodiments of the present application contains the battery of the above embodiments of the present application, the energy storage device has high energy storage density, good cycle performance, long service life, and high safety.

[0134] Embodiments

[0135] Hereinafter, the examples of the present application will be described. The examples described below are illustrative and are given to satisfy generic skeletal disclosure laws only and are not to be construed as limiting of the present application. Unless particular technical or conditions are mentioned in the examples, the technical or conditions described in the literature in the art or according to the product manual are used. Unless the manufacturer of the reagent or instrument is mentioned, it is a conventional product that can be obtained commercially.

[0136] 1. Composite cathode material and preparation method thereof

[0137] Example A1

[0138] The present example provides a composite cathode material and a preparation method thereof. The composite cathode material of the present example includes lithium-rich manganese-based cathode material particles, and a coating layer of the lithium-rich manganese-based cathode material particles on the surface of the lithium-rich manganese-based cathode material particles, the coating layer being a LaFeO3 perovskite-containing coating layer. The relevant parameters of the lithium-rich manganese-based cathode material particles and the coating layer are shown in 1 below.

[0139] The preparation method of the composite cathode material includes the following steps:

[0140] S1. Preparation of lithium-rich manganese-based cathode material particles: according to the molecular formula Li 1.2 Mn 0.48 Co 0.1 Ni 0.2 Ti 0.02 O2, the lithium salt Li2CO3, the manganese salt MnSO4·H2O, the cobalt salt CoSO4·7H2O, and the TiO2 precursor compounds are accurately weighed according to the molar ratio of the elements contained in the lithium-rich manganese-based cathode material, and each precursor compound is mixed with zirconium beads for ball milling at a ball-to-material ratio of 60:1 in a drum-type ball mill mixer to obtain a precursor mixture; the precursor mixture is placed in a muffle furnace for sintering treatment, the sintering temperature is 800°C, the heating rate is 2°C / min, the sintering time is 10h, the sintering atmosphere is air, and after sintering, the material is mechanically ground and vibrated to obtain lithium-rich manganese-based cathode material particles of the molecular formula Li 1.2 Mn 0.48 Co 0.1 Ni 0.2 Ti 0.02 O2.

[0141] S2. Preparation of perovskite coating layer on the surface of lithium-rich manganese-based cathode material particles:

[0142] The precursor materials of the perovskite material LaCl3 and Fe2O3 are put into a roller-type ball mill mixer in a proportion of 1:1 of La:Fe element molar ratio for 10 h of mixing, and then the lithium-rich manganese-based positive electrode material particles obtained in the above step S1 are added into the roller-type ball mill mixer for 10 h of mixing again. The total mass of the precursor materials of the perovskite material and the lithium-rich manganese-based positive electrode material particles is mixed in a proportion of 0.25:100 of the mass ratio of the perovskite LaFeO3 to the lithium-rich manganese-based positive electrode material particles. The obtained mixture is put into a muffle furnace for secondary sintering, the sintering temperature is 700℃, the heating rate is 3℃ / min, the sintering time is 9 h, and the sintering atmosphere is air. After sintering, the material is mechanically ground and vibrated to obtain a perovskite-coated lithium-rich manganese-based composite positive electrode material.

[0143] Examples A2 to A13

[0144] Examples A2 to A13 each provide a composite positive electrode material and a preparation method thereof. The structure of each composite positive electrode material provided in Examples A2 to A13 is the same as that of the composite positive electrode material in Example A1, and each composite positive electrode material is a core-shell structure, each composite positive electrode material comprising lithium-rich manganese-based positive electrode material particles (core) and a coating layer coating the core, the coating layer being a perovskite-containing coating layer. The relevant parameters of the lithium-rich manganese-based positive electrode material particles and the coating layer are shown in Table 1 below.

[0145] The preparation method of each composite positive electrode material provided in Examples A2 to A13 each refers to the preparation method of the composite positive electrode material in Example A1, wherein the type of the precursor material of the perovskite material and the secondary sintering conditions in S2 of the preparation method of each composite positive electrode material in Examples A2 to A13 are shown in Table 1 below.

[0146] Comparative Example A1

[0147] The present comparative example provides a lithium-rich positive electrode material and a preparation method thereof. The lithium-rich positive electrode material of the present comparative example is different from the composite positive electrode material in Example A1 in that it does not contain a coating layer, i.e. the lithium-rich manganese-based positive electrode material particles of the present comparative example are the core of the composite positive electrode material in Example A1.

[0148] Comparative Example A2

[0149] The present comparative example provides a composite positive electrode material and a preparation method thereof. The composite positive electrode material of the present comparative example is different from the composite positive electrode material in Example A2 in that the perovskite LaFeO3 in the coating layer is replaced by LaAlO3, and the others remain unchanged. The relevant parameters of the lithium-rich manganese-based positive electrode material particles and the coating layer contained in the composite positive electrode material of the present comparative example are shown in Table 1 below.

[0150] The preparation method of the composite cathode material comprises the following steps:

[0151] S1. Preparation of lithium-rich manganese-based cathode material particles: prepared according to the method in Example A2.

[0152] S2. Preparation of perovskite coating layer on the surface of lithium-rich manganese-based cathode material particles:

[0153] The precursor material LaCl3 and Al2O3 of the perovskite material are placed in a drum-type ball mill mixer in a La:Al element molar ratio of 1:1 for 10h of mixing, and then the lithium-rich manganese-based cathode material particles obtained in the above step S1 are added to the drum-type ball mill mixer for 10h of mixing treatment again; wherein the total mass of the precursor material of the perovskite material and the lithium-rich manganese-based cathode material particles are mixed in a perovskite LaAlO3 to lithium-rich manganese-based cathode material particle mass ratio of 0.4:100; the obtained mixture is placed in a muffle furnace for secondary sintering, the sintering temperature is 700℃, the heating rate is 3℃ / min, the sintering time is 9h, the sintering atmosphere is air, and after sintering, the material is mechanically ground and vibrated to obtain a perovskite-coated lithium-rich manganese-based composite cathode material.

[0154] Comparative Example A3

[0155] This comparative example provides a composite cathode material and a preparation method thereof. The composite cathode material of this comparative example is different from the composite cathode material in Example A2 in that the perovskite LaFeO3 in the coating layer is replaced by LaMnO3, and the others remain unchanged. The related parameters of the lithium-rich manganese-based cathode material particles and the coating layer contained in the composite cathode material of this comparative example are shown in the following 1.

[0156] The preparation method of the composite cathode material comprises the following steps:

[0157] S1. Preparation of lithium-rich manganese-based cathode material particles: prepared according to the method in Example A2.

[0158] S2. Preparation of perovskite coating layer on the surface of lithium-rich manganese-based cathode material particles:

[0159] The precursor material LaCl3 and Mn2O3 of the perovskite material are placed in a drum-type ball mill mixer in a La:Mn element molar ratio of 1:1 for 10h of mixing, and then the lithium-rich manganese-based cathode material particles obtained in the above step S1 are added to the drum-type ball mill mixer for 10h of mixing treatment again; the obtained mixture is placed in a muffle furnace for secondary sintering, the sintering temperature is 700℃, the heating rate is 3℃ / min, the sintering time is 9h, the sintering atmosphere is air, and after sintering, the material is mechanically ground and vibrated to obtain a perovskite-coated lithium-rich manganese-based composite cathode material.

[0160] 2. Positive electrode sheet, battery embodiment

[0161] Embodiment B1

[0162] This embodiment provides a positive electrode sheet and a battery cell containing the same. The battery cell of this embodiment comprises an electrode assembly formed by a positive electrode sheet, a separator and a negative electrode sheet, and further comprises an electrolyte. The positive electrode sheet contains the composite positive electrode material of Embodiment A1.

[0163] Preparation of the positive electrode sheet: the composite positive electrode material of Embodiment A1 is put into a 5-liter stirring tank for pre-mixing for 30 minutes, then the conductive agent acetylene black (SP) and the binder polyvinylidene fluoride (PVDF) are added for secondary dry mixing for 30 minutes, and then the solvent N-methyl pyrrolidone (NMP) is added for rapid stirring under vacuum to form a slurry. The mass ratio of the composite positive electrode material: acetylene black: polyvinylidene fluoride is 96:2:2, and the solid content of the slurry is 70% by weight. The slurry is uniformly coated on both sides of an aluminum foil with a thickness of 12 μm, and the coated electrode sheet is taken out after drying in an oven at 100-130°C for half an hour. The positive electrode active material loading of the electrode sheet is 21.5 mg / cm 2 ; and the removed positive electrode sheet is subjected to roller cold pressing to obtain a positive electrode sheet.

[0164] Preparation of the negative electrode sheet: the negative electrode active material artificial graphite, hard carbon, conductive agent acetylene black, binder styrene-butadiene rubber (SBR) and thickening agent sodium carboxymethyl cellulose (CMC) are fully stirred and mixed uniformly in a deionized water solvent system according to a weight ratio of 90:5:2:2:1, and then coated on a copper foil, dried and cold-pressed to obtain a negative electrode sheet.

[0165] Separator: a porous polyethylene polymer film with a thickness of 12 μm.

[0166] Electrolyte: 1 mol / L of LiPF6 / (solvent is EC+EMC+DMC, volume ratio is 1:1:1).

[0167] Battery cell: the positive electrode sheet, the separator and the negative electrode sheet are stacked in order with the separator in the middle of the positive and negative electrode sheets to play a role of isolation, and are wound to obtain a bare cell; the bare cell is placed in an outer package, the prepared base electrolyte is injected, and the package is sealed to obtain a full battery.

[0168] Embodiments B2 to B13

[0169] Embodiments B2 to B13 each provide a positive electrode sheet and a battery cell containing the same.

[0170] The positive electrode sheet provided in each of Embodiment B2 to Embodiment B13 is different from the positive electrode sheet in Embodiment B1 in that the positive electrode material contained in the positive electrode sheet in Embodiment B2 is the composite positive electrode material in Embodiment A2, the positive electrode material contained in the positive electrode sheet in Embodiment B3 is the composite positive electrode material in Embodiment A3, and so on, and the positive electrode material contained in the positive electrode sheet in Embodiment B13 is the composite positive electrode material in Embodiment A13, and the other aspects are the same as the positive electrode sheet in Embodiment B1.

[0171] The battery monomer provided in each of Embodiment B2 to Embodiment B13 is different from the battery monomer in Embodiment B1 in that the positive electrode sheet contained in the battery monomer in Embodiment B2 is the positive electrode sheet in Embodiment B2 of the present application, that is, the positive electrode material in the positive electrode sheet contained in the battery monomer in each embodiment is the composite positive electrode material in Embodiment A2, and so on, and the positive electrode sheet contained in the battery monomer in Embodiment B13 is the positive electrode sheet in Embodiment B13, and the other aspects are the same as the battery monomer in Embodiment B1.

[0172] The preparation method of the positive electrode sheet and the battery monomer provided in each of Embodiment B2 to Embodiment B13 respectively replaces the contained positive electrode material with the composite positive electrode material in the corresponding embodiment, and the other steps and preparation conditions are the same as the preparation steps and preparation conditions in Embodiment B1.

[0173] Comparative Example B1 to Comparative Example B3

[0174] The positive electrode sheet and the battery monomer containing the positive electrode sheet provided in each of Comparative Example B1 to Comparative Example B3 are provided.

[0175] The positive electrode sheet provided in each of Comparative Example B1 to Comparative Example B3 is different from the positive electrode sheet in Embodiment B1 in that the positive electrode material contained in the positive electrode sheet in Comparative Example B1 is the lithium-rich positive electrode material in Comparative Example A1, the positive electrode material contained in the positive electrode sheet in Comparative Example B2 is the composite positive electrode material in Comparative Example A2, and the positive electrode material contained in the positive electrode sheet in Comparative Example B3 is the composite positive electrode material in Comparative Example A3, and the other aspects are the same as the positive electrode sheet in Embodiment B1.

[0176] 3. Related performance test of composite positive electrode material and battery monomer:

[0177] 3.1. Related performance test of composite positive electrode material:

[0178] Each lithium-rich positive electrode material provided in Embodiments A1 to A13 and Comparative Examples A1 to A3 is respectively detected by the following method for the related parameters in Table 1.

[0179] The detection method of the thickness of the coating layer contained in the composite cathode material: the cross-section photo of the coating layer is scanned by transmission electron microscope (TEM), and then the distance between the inner wall and the outer wall of the coating layer is measured.

[0180] The detection method of the Dv50 particle size of the composite cathode material and the core contained therein: referring to GB / T 19077-2016 / ISO13320:2009 particle size distribution laser diffraction method, the equipment Malvern 3000 is used for detection.

[0181] The detection method of the dislocation density of the composite cathode material: based on XRD test β = (1 / D) 2 ×10 16 , wherein D = Kλ / Bcosθ, K = 0.9, λ = 1.5406, B is the half-height width of the (hkl) crystal plane of the composite cathode material in the XRD diffraction graph, and θ is the diffraction angle.

[0182] The detection method of the microstress of the composite cathode material: microstress = (βhkl×Cosθhkl) / (4sinθhkl), wherein θhkl is the diffraction angle of the (hkl) crystal plane of the composite cathode material in the XRD diffraction graph, and βhkl is the half-height width of the (hkl) crystal plane of the composite cathode material in the XRD diffraction graph.

[0183] The detection method of the BET specific surface area of the composite cathode material: referring to GB / T 19587-2004 gas adsorption BET method, the specific surface area of the composite cathode material is measured.

[0184] The results of the detection of the related performance of the composite cathode material and the battery cell are shown in Table 1 as follows:

[0185] Table 1

[0186]

[0187]

[0188] It can be known from Table 1 that the composite cathode material of the embodiments has appropriate range of dislocation density, microstress and specific surface area, so that the mechanical properties such as the particle structure strength of the composite cathode material of the embodiments are good, and the electrochemical properties such as the voltage stability and the stability of the contact interface with the electrolyte are improved. Moreover, the particle size thereof can be adjusted by adjusting the core particle size and the coating layer thickness, such as adjusting in the range in Table 1 above, so that the performance such as the compaction density of the composite cathode material can be improved at the same time.

[0189] 3.2 Detection of the related performance of the battery cell:

[0190] The battery cells provided in the above Examples B1 to B13 and Comparative Examples B1 to B3 were subjected to the relevant electrochemical performance tests in Table 2 using the following methods, and the results are shown in Table 2 below.

[0191] Battery gas production detection method: the battery cell was discharged at 0.1C to 2V and then rested for 30 min, then fully charged at 0.33C to 4.4V and rested for 30 days; the initial volume and the volume after resting for 30 days of the battery cell were tested by the drainage method, and the volume expansion rate of the battery cell was obtained, the volume expansion rate (%) = (volume after resting for 30 days / initial volume-1) x 100%.

[0192] Battery cell cycle retention rate (%): taking the full battery cell as the test object, in a constant temperature environment at 25°C, at a voltage of 2.5V-4.45V, charging at 1C rate to 4.45V, then constant voltage charging at 4.45V until the current is ≤0.05mA, resting for 5min, then discharging at 1C rate to 2.5V, recording the discharge capacity, repeating the previous process, obtaining the capacity retention rate after a specified number of cycles, the capacity retention rate = the first cycle discharge capacity / the discharge capacity at the specified number of cycles x 100%.

[0193] Battery cell storage performance test detection method: in a constant temperature environment at 25°C, rest for 5min, discharge at 1 / 3C to 2.5V, rest for 5min, charge at 1 / 3C to 4.5V, then constant voltage charge at 4.5V until the current is ≤0.05mA, rest for 5min, at this time the charge capacity is recorded as C0, then discharge at 1 / 3C to 2.8V, the initial discharge capacity at this time is recorded as D0; then the battery is charged at 0.33C to 4.5V and constant voltage to current ≤0.05mA, rest for 5min, and finally put into a high and low temperature box at 60°C, rest for 1h until the battery temperature reaches the target temperature, then store; after 15 days, take out and repeat the previous process in a constant temperature environment at 25°C, and record the capacity Dn (n=0, 1, 2…) every 15 days, calculate the capacity retention rate after 60 days of storage: (D4-D0) / D0*100%.

[0194] Battery capacity detection: in a constant temperature environment at 25°C, rest for 30min, discharge at 0.33C to 2.3V, rest for 5min, charge at 0.33C to 4.55V, then constant voltage charge at 4.55V until the current is ≤0.05mA, rest for 5min, then discharge at 0.33C to 2.3V, at this time the discharge capacity is the initial discharge capacity.

[0195] The relevant performance tests of the battery cell are shown in Table 2 below:

[0196] Table 2

[0197]

[0198] As can be seen from the data in Table 2, compared with the battery monomer in Comparative Examples B1 to B3, the battery monomer in Examples B1 to B13 has relatively higher storage performance and cycle performance, relatively increased gram capacity, and relatively low gas production. Among them, compared with Comparative Example B1, the capacity retention rate of the battery in Example B5 is significantly improved, the gas production is significantly reduced, and the gram capacity and other performances are also improved. Therefore, on the basis of the same lithium-rich manganese-based positive electrode material particles, the addition of the perovskite containing coating layer can alleviate the oxygen release phenomenon of the composite positive electrode material and improve the stability of the interface contact between the composite positive electrode material and the electrolyte. Compared with Comparative Examples B2 and B3, the capacity retention rate of the battery in Examples B2, B7 to B13 is also significantly improved, the gas production is significantly reduced, and the gram capacity and other performances are also improved. Therefore, on the basis of the same lithium-rich manganese-based positive electrode material particles and the same or similar thickness of the coating layer, the type of perovskite material contained in the coating layer of the composite positive electrode material of the present application can significantly alleviate the oxygen release phenomenon of the composite positive electrode material compared with LaAlO3, LaMnO3 and other perovskites, and further improve the stability of the interface contact between the composite positive electrode material and the electrolyte.

[0199] The coating layer contained in the composite positive electrode material of the present application. The capacity retention rate of the battery in Example B5 is significantly improved compared with Comparative Example B1, the gas production is significantly reduced, and the gram capacity and other performances are also improved. Example B2, therefore, by controlling the perovskite material contained in the coating layer, the composite positive electrode material of the present application significantly alleviates the oxygen release phenomenon of the lithium-rich positive electrode material contained therein, and improves the capacity stability and cycle performance of the composite positive electrode material.

[0200] Further compare Examples B1 to B6, wherein the battery monomer related performance in Examples B1 to B4 is better than Examples B5 to B6, therefore, on the basis of the same perovskite material contained in the composite positive electrode material, further adjusting the thickness of the coating layer or the mass ratio of the perovskite material to the core, can further adjust the role of the coating layer in alleviating the oxygen release of the core positive electrode material, such as controlling the coating layer to be 0.05 to 1 μm, further 0.1 to 0.4 μm range or the mass ratio of the core to the perovskite is 100:0.25 to 100:0.8, compared with other content range, the oxygen release phenomenon of the lithium-rich positive electrode material contained in the composite positive electrode material is significantly alleviated, and the capacity stability and cycle performance of the composite positive electrode material are further improved.

[0201] Further comparing the example B2 and B7 to B13, on the basis of the same or similar content of perovskite material in the composite cathode material of each example, changing the type of perovskite material can still alleviate the oxygen release phenomenon of the lithium-rich cathode material contained in the composite cathode material, and improve the capacity stability and cycle performance of the composite cathode material.

[0202] Finally, it should be noted that: the above examples are only used to illustrate the technical solutions of the present application, but not to limit them; although the present application has been described in detail with reference to the foregoing examples, those skilled in the art should understand that: it can still modify the technical solutions recorded in the foregoing examples, or make equivalent replacement for part or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the examples of the present application, and they should be covered in the scope of the claims and the description of the present application. Especially, as long as there is no structural conflict, each technical feature mentioned in each example can be combined in any way. The present application is not limited to the specific examples disclosed in the text, but includes all technical solutions falling within the scope of the claims.

Claims

1. A composite cathode material comprising a core and a coating layer coating the core, characterized in that: The core contains a lithium-rich positive electrode material, and the coating layer contains an ABO3 perovskite, wherein A includes at least one of La and Sr, and B includes at least one of Fe, Ti, Mo, Ga, Ru, Zr, Ir and Co; the total content of A and B in the ABO3 perovskite in the composite positive electrode material is 800-5400 ppm.

2. The composite cathode material of claim 1, wherein: The ABO3 perovskite includes at least one of LaFeO3, LaTiO3, LaMoO3, LaGaO3, LaRuO3, SrTiO3, SrZrO3, LaIrO3 and LaCoO3.

3. The composite cathode material of claim 1 or 2, wherein: The total content of A and B in the ABO3 perovskite in the composite positive electrode material is 1200-5000 ppm. The mass ratio of the ABO3 perovskite to the core is (0.2-0.8):

100.

4. The composite cathode material of claim 3, wherein, The mass ratio of the ABO3 perovskite to the core is (0.25-0.7):

100.

5. The composite cathode material of claim 1 or 2, wherein: The lithium-rich cathode material includes a lithium-rich manganese-based cathode material, the lithium-rich manganese-based cathode material is Li[Li x Ni a Co b Mn c M d ]O2, wherein x+a+b+c+d=1, x>0, a+b+c+d<1, 0<b<0.1, and M includes at least one of Mg, Nb, Cr, Ce, Fe, Ta, Al, V, Ti, Zr, Sn and Mo.

6. The composite cathode material of claim 1 or 2, wherein: The Dv50 particle size of the core is 5-11 μm.

7. The composite cathode material of claim 6, wherein: The Dv50 particle size of the core is 6-8 μm.

8. The composite cathode material of claim 1, wherein: The composite positive electrode material has at least one of the following (1) to (4): (1) dislocation density of 1.55 x 10 11 3.5 x 10 11 m / m -3 ; (2) the micro stress is 0.3%-3.0%; (3) a specific surface area BET of 1.2 to 2.5 m2 / g 2 / g; (4) the Dv50 particle size is 6.5-11 μm.

9. The composite cathode material of claim 8, wherein: The composite positive electrode material has at least one of the following (1) to (4): (1) dislocation density of 1.8 x 10 11 3.2 x 10 11 m / m -3 ; (2) the micro stress is 0.3%-1.0%; (3) the specific surface area BET is 1.35-2.3 m 2 / g; (4) the Dv50 particle size is 7-10.5 μm.

10. A method of preparing a composite cathode material, characterized by, The method comprises the following steps: mixing the positive electrode material particles with an ABO3 perovskite precursor to obtain a mixture; sintering the mixture to form a coating layer containing the ABO3 perovskite on the surface of the positive electrode material particles, thereby obtaining a composite positive electrode material; The positive electrode material particles contain a lithium-rich positive electrode material, A in the ABO3 perovskite includes at least one of La and Sr, and B includes at least one of Fe, Ti, Mo, Ga, Ru, Zr, Ir and Co; the total content of A and B in the ABO3 perovskite in the composite positive electrode material is 800-5400 ppm.

11. The production method according to claim 10, characterized by: The ABO3 perovskite precursor includes at least one of LaFeO3, LaTiO3, LaMoO3, LaGaO3, LaRuO3, SrTiO3, SrZrO3, LaIrO3 and LaCoO3.

12. The production method according to claim 10 or 11, characterized by: The sintering process includes at least one of the following (1) to (3): (1) the sintering temperature is 500-750 ℃; (2) the temperature is raised to the sintering temperature at a rate of 2-5 ℃ / min; (3) when the sintering temperature is 500-650 ℃, the sintering time is 6-10 h.

13. The production method according to claim 12, characterized by: The sintering temperature is 500-650 ℃.

14. A positive electrode, characterized by comprising: The composite positive electrode material contains the composite positive electrode material of any one of claims 1-9 or is prepared by the preparation method of any one of claims 10-13.

15. A battery, characterized by The positive electrode comprises the positive electrode of claim 14.

16. An electrical device, comprising: The battery comprises the battery of claim 15.

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