A positive electrode material and its preparation method and application

Abstract

The present application discloses a positive electrode material and a preparation method and application thereof, comprising a positive electrode material core layer and a flame retardant coating layer, wherein the flame retardant coating layer is composed of a polyphosphate ammonium polymer main chain [(PO4NH4)] m , cross-linking region X, phosphate side chain [(PO3Y)] n When thermal runaway occurs inside a lithium-ion battery, the flame-retardant coating can capture the active oxygen released by the positive electrode at high temperature, preventing the active oxygen from reacting violently with the flammable electrolyte and the negative electrode to release heat, and forming a dense coating layer on the positive electrode surface to block the side reactions between the highly oxidizing positive electrode and the electrolyte and the negative electrode, thereby improving the battery safety and cycle performance.

Description

Technical Field

[0001] The present invention relates to the field of electrochemistry, and in particular to a cathode material, a preparation method thereof, and an application thereof. Background Art

[0002] Since the commercialization of lithium-ion batteries, lithium-ion batteries have rapidly become the primary choice for energy storage components in devices such as computers, power tools, and digital cameras due to their advantages of high energy density, long cycle life, and high safety. In recent years, with the rapid rise of the electric vehicle market, lithium-ion batteries have been more widely used. However, with the widespread application of lithium-ion batteries, problems such as uneven distribution of lithium resources and relative shortage of resources have gradually emerged.

[0003] For new energy vehicles, lithium-ion power batteries are their core components, and their safety has received extensive attention from the public. However, safety accidents of lithium-ion battery systems characterized by thermal runaway occur from time to time, seriously threatening the life and property safety of passengers. Summary of the Invention

[0004] In view of the above problems, the present application provides a cathode material, a preparation method thereof, and an application thereof, which can effectively prevent the thermal runaway problem that occurs during the use of lithium-ion batteries.

[0005] In a first aspect, the present application provides a cathode material, which is characterized by comprising a core and a flame-retardant coating layer coated on the surface of the core, and the flame-retardant coating layer comprises a polyammonium phosphate polymer main chain a crosslinked region X and a phosphate ester side chain The flame-retardant coating layer is a polymer represented by Formula I:

[0006]

[0007] wherein the unit structure of the crosslinked region X is X1 and X2 are each independently selected from one of -CH2-, -CH2-O-, -C(=O)-O-, -NH-, -Si(-O-)3; R1 is a C1-C 10 alkyl group, a C1-C 10 aryl group, a C1-C 10 polyether; 10 < m < 10000; 1 < n < 1000; Y is a C1-C 10 alkyl group or a C1-C 10 aryl group.

[0008] In the technical scheme of the embodiment of the present application, ammonium polyphosphate and phosphate are both flame retardants with excellent performance, and the cross-linking of the two can play a multiple flame retardant role. Moreover, the flame retardant coating layer directly coated on the surface of the inner core can better exert the flame retardant effect. On the one hand, the chemical molecules in the flame retardant coating layer will decompose and produce free radicals at high temperatures, and timely capture the active oxygen released by the positive electrode to prevent the active oxygen from diffusing and spreading in the battery and reacting violently with the combustibles in the battery to produce exothermic side reactions, leading to thermal runaway; on the other hand, the flame retardant coating layer can form a dense barrier layer on the surface of the positive electrode at high temperatures to prevent the highly oxidizing positive electrode from contacting the electrolyte and the anode, and avoid the heat generated by violent exothermic side reactions such as crosstalk between the positive and negative electrodes, thereby greatly reducing the heat generated by thermal runaway of the battery and significantly improving the safety performance of the battery.

[0009] In any embodiment, the chemical structure of the flame retardant coating is 200 <m<2000,1<n<100。

[0010] The molecular weight of the polymer should be appropriate and should not be too large or too small, otherwise it will affect the cross-linking effect.

[0011] In any embodiment, the coverage of the flame retardant coating layer is 40% to 100%, and optionally 60% to 90%.

[0012] The flame retardant coating layer needs to have a sufficiently large coverage rate to effectively play a flame retardant role and prevent thermal runaway of the battery; the coverage rate of the flame retardant coating layer in the range of 60% to 90% is both economical and can better exert the flame retardant effect.

[0013] In any embodiment, the thickness of the flame retardant coating layer is 10 nm to 1000 nm, optionally 20 nm to 100 nm.

[0014] The thickness of the flame retardant coating should be within a suitable range. If it is too thin, the flame retardant effect will be insufficient, while if it is too thick, it will affect the battery group margin, thereby reducing the performance of the battery.

[0015] In any embodiment, the specific surface area of ​​the flame retardant coating is 1 m 2 / g~100m 2 / g.

[0016] By adopting the specific surface area within the above range, it is possible to take into account both the flame retardant effect and the electrochemical performance and processing performance of the battery.

[0017] In any embodiment, the core includes at least one of an olivine-structured lithium phosphate, a lithium transition metal oxide, and their respective modified compounds, optionally at least one of lithium cobalt oxide, lithium manganese oxide, lithium nickel oxide, lithium titanium oxide, lithium nickel manganese oxide, and lithium nickel cobalt manganese composite oxide, further optionally LiFePO4, LiMnPO4, LiCoO2, LiNi 0.6 Co0.2 Mn 0.2 O2, LiNi 0.8 Co 0.1 Mn 0.1 O2, LiNi 0.9 Co 0.05 Mn 0.05 O2, LiNi 0.8 Co 0.1 Al 0.1 at least one of O2.

[0018] These compounds are cathode materials with good safety. The cathode material is the main source of lithium ions in a lithium-ion battery and is the most core part of a lithium battery. The performance of the cathode material directly affects the performance of the lithium-ion battery.

[0019] In a second aspect, the present application provides a method for preparing the above-mentioned material, including the following steps: providing ammonium polyphosphate and a phosphate ester, dispersing the ammonium polyphosphate and the phosphate ester in a solvent, adding a cross-linking agent and a catalyst, and stirring evenly to obtain a flame retardant; processing the flame retardant and the core together to obtain a cathode material;

[0020] The cathode material includes the core and a flame retardant coating layer coated on the surface of the core. The flame retardant coating layer includes a high molecular main chain of ammonium polyphosphate a cross-linked region X and phosphate ester branches The flame retardant coating layer is a polymer as described in Formula I:

[0021]

[0022] wherein the unit structure of the cross-linked region X is [X1-R1-X2], X1 and X2 are each independently selected from one of -CH2-, -CH2-O-, -C(=O)-O-, -NH-, -Si(-O-)3; R1 is a C1-C 10 alkyl group, a C1-C 10 aryl group, a C1-C 10 polyether; 10 < m < 10000; 1 < n < 1000; Y is a C1-C 10 alkyl group or a C1-C 10 aryl group.

[0023] Phosphate esters are chemically covalently cross-linked on the ammonium polyphosphate polymer skeleton and will not dissolve or diffuse into the electrolyte, which would have a negative impact on battery performance. Moreover, by adjusting the preparation conditions and the molecular structure of the flame retardant, the thermal response temperature of the flame retardant coating can be adjusted to adapt to the oxygen release temperature of various positive electrode materials, and to capture the released active oxygen in time to prevent thermal runaway of the battery. Therefore, the flame retardant coating obtained by this method can not only play a good flame retardant effect, but also improve the structural stability of the positive electrode material, alleviate the volume expansion and contraction of the positive electrode material during the charge and discharge process, and prevent the positive electrode material from breaking during the cycle, resulting in capacity loss, thereby improving the battery cycle life.

[0024] In any embodiment, the processing comprises: placing the flame retardant and the core together in a ball milling jar, and ball milling for 1 h to 24 h at a rotation speed of 100 r / min to 800 r / min to obtain the positive electrode material.

[0025] The ball milling method is simple, accurate and controllable, and can obtain positive electrode materials with excellent performance.

[0026] In any embodiment, the processing comprises: dispersing the flame retardant and the core in a solvent, and using a spray dryer to spray dry at 80° C. to 200° C. to obtain the positive electrode material.

[0027] The spray drying method is very convenient and can produce positive electrode materials conveniently and efficiently.

[0028] In any embodiment, the structural formula of the phosphate ester is as follows:

[0029]

[0030] Wherein, R1 and R2 are independently selected from C1 to C 10 Alkyl, C1~C 10 Aromatic group, C1~C 10 Olefins, C1~C 10 Alkoxy, C1~C 10 Carboxyl, C1~C 10 At least one of alcohol, amino, hydroxyl, -Cl, and -Br;

[0031] The core includes at least one of an olivine-structured lithium phosphate, a lithium transition metal oxide, and their respective modified compounds, optionally at least one of lithium cobalt oxide, lithium manganese oxide, lithium nickel oxide, lithium titanium oxide, lithium nickel manganese oxide, and lithium nickel cobalt manganese composite oxide, and further optionally at least one of LiFePO4, LiMnPO4, LiCoO2, LiNi 0.6 Co 0.2 Mn 0.2 O2、LiNi0.8 Co 0.1 Mn 0.1 O2、LiNi 0.9 Co 0.05 Mn 0.05 O2、LiNi 0.8 Co 0.1 Al 0.1 At least one of O2.

[0032] A variety of phosphates are chemically covalently cross-linked on the ammonium polyphosphate polymer skeleton, which can adjust the thermal response temperature of the flame-retardant coating layer, thereby adapting to the oxygen release temperature of various positive electrode materials; further combined with the use of a safer inner core, it is more conducive to ensuring the flame retardant effect of the battery.

[0033] In a third aspect, the present application provides a secondary battery, comprising a positive electrode, a negative electrode, an electrolyte and a separator, characterized in that it comprises the aforementioned positive electrode material or the positive electrode material prepared by the aforementioned method.

[0034] Secondary batteries that use materials with flame-retardant coatings can promptly exert their flame-retardant effects and prevent the highly oxidizing positive electrode from contacting the electrolyte and anode, avoiding heat generation from violent exothermic side reactions such as crosstalk between the positive and negative electrodes, thereby greatly reducing heat generation from thermal runaway of the battery and significantly improving battery safety performance.

[0035] In a fourth aspect, the present application provides a battery module, comprising the aforementioned secondary battery.

[0036] The flame retardant coating of the secondary battery can not only effectively avoid thermal runaway, but also reduce the side reaction between the highly oxidizing positive electrode and the electrolyte, thereby improving the high voltage cycle performance of the battery. Therefore, the battery module containing such a secondary battery has good overall safety performance.

[0037] In a fifth aspect, the present application provides a battery pack comprising the aforementioned battery module.

[0038] Because it contains battery modules with good safety performance, the performance of this battery pack is more efficient and stable.

[0039] In a sixth aspect, the present application provides an electrical device comprising at least one of the aforementioned secondary batteries, battery modules or battery packs.

[0040] The battery pack of the present application maintains a controllable temperature due to the flame-retardant coating layer, which is beneficial to the safe operation of the electrical device containing the battery pack and avoids thermal runaway.

[0041] The above description is only an overview of the technical solution of the present application. In order to more clearly understand the technical means of the present application, it can be implemented in accordance with the contents of the specification. In order to make the above and other purposes, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are listed below. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] Various other advantages and benefits will become apparent to those of ordinary skill in the art by reading the detailed description of the preferred embodiments below.The accompanying drawings are only for the purpose of illustrating the preferred embodiments and are not to be considered as limiting the present application.

[0043] Figure 1 It is a schematic diagram of the positive electrode material.

[0044] Figure 2 is a schematic diagram of a secondary battery according to one embodiment of the present application.

[0045] Figure 3 yes Figure 2 An exploded view of a secondary battery according to an embodiment of the present application is shown.

[0046] Figure 4 is a schematic diagram of a battery module according to an embodiment of the present application.

[0047] Figure 5 It is a schematic diagram of a battery pack according to one embodiment of the present application.

[0048] Figure 6 yes Figure 5 An exploded view of a battery pack according to an embodiment of the present application is shown.

[0049] Figure 7 FIG. 1 is a schematic diagram of an electric device using a secondary battery according to an embodiment of the present application as a power source.

[0050] Description of reference numerals:

[0051] 1 battery pack; 2 upper box; 3 lower box; 4 battery module; 5 secondary battery; 51 shell; 52 electrode assembly; 53 top cover assembly. DETAILED DESCRIPTION

[0052] The following embodiments of the technical solution of the present application are described in detail in conjunction with the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present application, and are therefore only used as examples, and cannot be used to limit the scope of protection of the present application.

[0053] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by technicians in the technical field to which this application belongs; the terms used herein are only for the purpose of describing specific embodiments and are not intended to limit this application; the terms "including" and "having" in the specification and claims of this application and the above-mentioned figure descriptions and any variations thereof are intended to cover non-exclusive inclusions.

[0054] Reference to "embodiments" herein means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment of the present application. The appearance of the phrase in various locations in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0055] In the description of the embodiments of the present application, the term "and / or" is only a description of the association relationship of the associated objects, indicating that there may be three relationships. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. In addition, the character " / " in this article generally indicates that the associated objects before and after are in an "or" relationship.

[0056] Reference herein to "one or more" or "at least one" means that at least one of the element is present; a plurality of such elements may be present unless explicitly and specifically defined otherwise.

[0057] During the thermal runaway of lithium-ion batteries, the positive electrode releases active oxygen at high temperature. The violent exothermic side reactions between the active oxygen and the flammable electrolyte and the negative electrode, and between the highly oxidizing positive electrode and the negative electrode are the main causes of battery combustion and explosion.

[0058] There are already some technologies to prevent battery thermal runaway, such as using a core-shell structured flame retardant additive, including a flame retardant core layer and an organic or inorganic shell layer. Before the battery electrolyte temperature reaches the combustion temperature, the flame retardant is released from the shell layer, allowing the flame retardant to play a flame retardant role and prevent the battery from burning and exploding.

[0059] However, the flame retardants in these technologies are selected from one of the organic phosphorus flame retardants, inorganic phosphorus flame retardants, and silicon flame retardants. They have a single flame retardant function and low efficiency, and cannot fully guarantee battery safety. In addition, the thermal runaway triggering of the battery often occurs in an instant. The flame retardant is coated on the surface of the positive electrode, negative electrode or diaphragm through a binder, or poured into the positive and negative electrode sheets. There is a long diffusion path between the flame retardant additive and the active material. The flame retardant may not have time to exert its effect before the battery has already experienced thermal runaway. Moreover, the shell layer of the flame retardant additive is prone to swelling and rupture when immersed in the electrolyte, resulting in leakage of the internal flame retardant core layer, thereby affecting battery performance.

[0060] Based on the above considerations, in order to simultaneously solve the problems of low flame retardancy efficiency, untimely flame retardancy, and easy leakage, the inventor has conducted in-depth research and designed a cathode material, including a core and a flame retardant coating layer, wherein the flame retardant coating layer is coated on the surface of the core, and the flame retardant coating layer is composed of a polyammonium phosphate polymer main chain [(PO4NH4) m , a crosslinking region X, and a phosphate ester side chain [(PO3Y) n . In this way, on the one hand, the flame retardant is crosslinked by two flame retardant materials, avoiding the problem of low flame retardancy efficiency caused by the single flame retardancy function. On the other hand, the flame retardant is located on the surface of the core layer of the cathode material, which can retard the flame in time and will not leak, significantly improving the battery safety performance.

[0061] The cathode material provided by this application can be widely used in various batteries.

[0062] In a first aspect, this application provides a cathode material, characterized in that it includes a core and a flame retardant coating layer coated on the surface of the core, and the flame retardant coating layer includes a polyammonium phosphate polymer main chain a crosslinking region X and a phosphate ester side chain The flame retardant coating layer is a polymer shown in Formula I:

[0063]

[0064] Among them, the unit structure of the crosslinking region X is X1 and X2 are each independently selected from one of -CH2-, -CH2-O-, -C(=O)-O-, -NH-, -Si(-O-)3; R1 is C1-C 10 alkyl, C1-C 10 aryl, C1-C 10 polyether; 10 < m < 10000; 1 < n < 1000; Y is C1-C 10 alkyl or C1-C 10 aryl.

[0065] "Crosslinking" refers to the process of connecting linear or branched polymer chains by covalent bonds to form a network or three-dimensional polymer.

[0066] The schematic diagram of the cathode material of this application refers to Figure 1 , and the flame retardant coating layer is coated on the surface of the core.

[0067] In the technical scheme of the embodiment of the present application, ammonium polyphosphate and phosphate are both flame retardants with excellent performance, and the cross-linking of the two can play multiple flame retardant effects. Moreover, the flame retardant coating layer directly coated on the surface of the inner core can better exert the flame retardant effect. On the one hand, the chemical molecules in the flame retardant coating layer will decompose and produce free radicals at high temperatures, and timely capture the active oxygen released by the positive electrode to prevent the active oxygen from diffusing and spreading in the battery and reacting violently with the combustibles in the battery to produce exothermic side reactions, leading to thermal runaway; on the other hand, the flame retardant coating layer can form a dense barrier layer on the surface of the positive electrode at high temperatures to prevent the highly oxidizing positive electrode from contacting the electrolyte and the anode, and avoid the heat generated by violent exothermic side reactions such as crosstalk between the positive and negative electrodes, thereby greatly reducing the heat generated by thermal runaway of the battery and significantly improving the safety performance of the battery.

[0068] In some embodiments, the chemical structure of the flame retardant coating is 200 <m<2000,1<n<100。

[0069] The molecular weight of the polymer should be appropriate and should not be too large or too small, otherwise it will affect the cross-linking effect.

[0070] In some embodiments, the coverage of the flame retardant coating layer is 40% to 100%, and optionally 60% to 90%.

[0071] The flame retardant coating layer needs to have a sufficiently large coverage rate to effectively play a flame retardant role and prevent thermal runaway of the battery; the flame retardant coating layer can play a good flame retardant role when the coverage rate is in the range of 60% to 90%.

[0072] In some embodiments, the thickness of the flame retardant coating layer is 10 nm to 1000 nm, optionally 20 nm to 100 nm.

[0073] The thickness of the flame retardant coating should be within a suitable range. If it is too thin, the flame retardant effect will be insufficient, while if it is too thick, it will affect the battery group margin, thereby reducing the performance of the battery.

[0074] In some embodiments, the specific surface area of ​​the flame retardant coating is 1 m 2 / g~100m 2 / g.

[0075] By adopting the specific surface area within the above range, it is possible to take into account both the flame retardant effect and the electrochemical performance and processing performance of the battery.

[0076] In some embodiments, the core includes at least one of an olivine-structured lithium phosphate, a lithium transition metal oxide, and their respective modified compounds, optionally at least one of lithium cobalt oxide, lithium manganese oxide, lithium nickel oxide, lithium titanium oxide, lithium nickel manganese oxide, and lithium nickel cobalt manganese composite oxide, further optionally LiFePO4, LiMnPO4, LiCoO2, LiNi 0.6 Co0.2 Mn 0.2 O2, LiNi 0.8 Co 0.1 Mn 0.1 O2, LiNi 0.9 Co 0.05 Mn 0.05 O2, LiNi 0.8 Co 0.1 Al 0.1 At least one of O2.

[0077] These compounds are cathode materials with good safety. The cathode material is the main source of lithium ions in a lithium-ion battery and is the most core part of the lithium battery. The performance of the cathode material directly affects the performance of the lithium-ion battery.

[0078] Second, the present application provides a method for preparing the above-mentioned material, including the following steps: providing ammonium polyphosphate and phosphate ester, dispersing the ammonium polyphosphate and the phosphate ester in a solvent, adding a cross-linking agent and a catalyst, and stirring evenly to obtain a flame retardant; processing the flame retardant and the core together to obtain a cathode material;

[0079] The cathode material includes the core and a flame retardant coating layer coated on the surface of the core. The flame retardant coating layer includes an ammonium polyphosphate polymer main chain Cross-linking region X and phosphate ester side chains The flame retardant coating layer is a polymer shown in Formula I:

[0080]

[0081] Among them, the unit structure of the cross-linking region X is X1 and X2 are each independently selected from one of -CH2-, -CH2-O-, -C(=O)-O-, -NH-, -Si(-O-)3; R1 is C1-C 10 alkyl, C1-C 10 aryl, C1-C 10 polyether; 10 < m < 10000; 1 < n < 1000; Y is C1-C 10 alkyl or C1-C 10 aryl.

[0082] Phosphate esters are chemically covalently cross-linked on the ammonium polyphosphate polymer skeleton and will not dissolve or diffuse into the electrolyte, which would have a negative impact on battery performance. Moreover, by adjusting the preparation conditions and the molecular structure of the flame retardant, the thermal response temperature of the flame retardant coating can be adjusted to adapt to the oxygen release temperature of various positive electrode materials, and to capture the released active oxygen in time to prevent thermal runaway of the battery. Therefore, the flame retardant coating obtained by this method can not only play a good flame retardant effect, but also improve the structural stability of the positive electrode material, alleviate the volume expansion and contraction of the positive electrode material during the charge and discharge process, and prevent the positive electrode material from breaking during the cycle, resulting in capacity loss, thereby improving the battery cycle life.

[0083] In some embodiments, the processing includes: placing the flame retardant and the core into a ball mill, and ball milling at a rotation speed of 100 r / min to 800 r / min for 1 h to 24 h to obtain the positive electrode material.

[0084] The ball milling method is simple, accurate and controllable, and can obtain positive electrode materials with excellent performance.

[0085] In some embodiments, the processing includes: dispersing the flame retardant and the core in a solvent, and using a spray dryer to spray dry at 80° C. to 200° C. to obtain the positive electrode material.

[0086] The spray drying method is very convenient and can produce positive electrode materials conveniently and efficiently.

[0087] In some embodiments, the structural formula of the phosphate ester is as follows:

[0088]

[0089] Wherein, R1 and R2 are independently selected from C1 to C 10 Alkyl, C1~C 10 Aromatic group, C1~C 10 Olefins, C1~C 10 Alkoxy, C1~C 10 Carboxyl, C1~C 10 At least one of alcohol, amino, hydroxyl, -Cl, and -Br;

[0090] The core includes at least one of an olivine-structured lithium phosphate, a lithium transition metal oxide, and their respective modified compounds, optionally at least one of lithium cobalt oxide, lithium manganese oxide, lithium nickel oxide, lithium titanium oxide, lithium nickel manganese oxide, and lithium nickel cobalt manganese composite oxide, and further optionally at least one of LiFePO4, LiMnPO4, LiCoO2, LiNi 0.6 Co 0.2 Mn 0.2 O2、LiNi0.8 Co 0.1 Mn 0.1 O2、LiNi 0.9 Co 0.05 Mn 0.05 O2、LiNi 0.8 Co 0.1 Al 0.1 At least one of O2.

[0091] In some embodiments, the positive electrode active material may be a positive electrode active material for a battery known in the art.

[0092] A variety of phosphates are chemically covalently cross-linked on the ammonium polyphosphate polymer skeleton, which can adjust the thermal response temperature of the flame-retardant coating layer, thereby adapting to the oxygen release temperature of various positive electrode materials; further combined with the use of a safer inner core, it is more conducive to ensuring the flame retardant effect of the battery.

[0093] In a third aspect, the present application provides a secondary battery, comprising a positive electrode, a negative electrode, an electrolyte and a separator, characterized in that it comprises the aforementioned positive electrode material or the positive electrode material prepared by the aforementioned method.

[0094] Secondary batteries that use materials with flame-retardant coatings can promptly exert their flame-retardant effects and prevent the highly oxidizing positive electrode from contacting the electrolyte and anode, avoiding heat generation from violent exothermic side reactions such as crosstalk between the positive and negative electrodes, thereby greatly reducing heat generation from thermal runaway of the battery and significantly improving battery safety performance.

[0095] In a fourth aspect, the present application provides a battery module, comprising the aforementioned secondary battery.

[0096] The flame retardant coating of the secondary battery can not only effectively avoid thermal runaway, but also reduce the side reaction between the highly oxidizing positive electrode and the electrolyte, thereby improving the high voltage cycle performance of the battery. Therefore, the battery module containing such a secondary battery has good overall safety performance.

[0097] In a fifth aspect, the present application provides a battery pack comprising the aforementioned battery module.

[0098] Because it contains battery modules with good safety performance, the performance of this battery pack is more efficient and stable.

[0099] In a sixth aspect, the present application provides an electrical device comprising at least one of the aforementioned secondary batteries, battery modules or battery packs.

[0100] The battery pack of the present application maintains a controllable temperature due to the flame-retardant coating layer, which is beneficial to the safe operation of the electrical device containing the battery pack and avoids thermal runaway.

[0101] In addition, the secondary battery, battery module, battery pack, and electric device of the present application will be described below with reference to the drawings as appropriate.

[0102] Generally, a secondary battery includes a positive electrode sheet, a negative electrode sheet, an electrolyte and a separator. During the battery charging and discharging process, active ions are embedded and released back and forth between the positive electrode sheet and the negative electrode sheet. The electrolyte plays the role of conducting ions between the positive electrode sheet and the negative electrode sheet. The separator is set between the positive electrode sheet and the negative electrode sheet, mainly to prevent the positive and negative electrodes from short-circuiting, while allowing ions to pass through.

[0103] [Positive electrode]

[0104] The positive electrode sheet includes a positive electrode current collector and a positive electrode film layer arranged on at least one surface of the positive electrode current collector, wherein the positive electrode film layer includes the positive electrode active material of the first aspect of the present application.

[0105] As an example, the positive electrode current collector has two surfaces opposite to each other in its thickness direction, and the positive electrode film layer is disposed on any one or both of the two opposite surfaces of the positive electrode current collector.

[0106] In some embodiments, the positive electrode current collector may be a metal foil or a composite current collector. For example, aluminum foil may be used as the metal foil. The composite current collector may include a polymer material base and a metal layer formed on at least one surface of the polymer material base. The composite current collector may be formed by forming a metal material (aluminum, aluminum alloy, nickel, nickel alloy, titanium, titanium alloy, silver and silver alloy, etc.) on a polymer material substrate (such as a substrate of polypropylene (PP), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polystyrene (PS), polyethylene (PE), etc.).

[0107] In some embodiments, the positive electrode film layer may further optionally include a binder. As an example, the binder may include at least one of polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), vinylidene fluoride-tetrafluoroethylene-propylene terpolymer, vinylidene fluoride-hexafluoropropylene-tetrafluoroethylene terpolymer, tetrafluoroethylene-hexafluoropropylene copolymer, and fluorine-containing acrylate resin.

[0108] In some embodiments, the positive electrode film layer may further include a conductive agent, which may include, for example, at least one of superconducting carbon, acetylene black, carbon black, Ketjen black, carbon dots, carbon nanotubes, graphene, and carbon nanofibers.

[0109] In some embodiments, the positive electrode sheet can be prepared in the following manner: the components for preparing the positive electrode sheet, such as the positive electrode active material, the conductive agent, the binder and any other components are dispersed in a solvent (such as N-methylpyrrolidone) to form a positive electrode slurry; the positive electrode slurry is coated on the positive electrode collector, and after drying, cold pressing and other processes, the positive electrode sheet can be obtained.

[0110] [Negative electrode]

[0111] The negative electrode sheet includes a negative electrode current collector and a negative electrode film layer disposed on at least one surface of the negative electrode current collector, wherein the negative electrode film layer includes a negative electrode active material.

[0112] As an example, the negative electrode current collector has two surfaces opposite to each other in its thickness direction, and the negative electrode film layer is disposed on any one or both of the two opposite surfaces of the negative electrode current collector.

[0113] In some embodiments, the negative electrode current collector may be a metal foil or a composite current collector. For example, as the metal foil, copper foil may be used. The composite current collector may include a polymer material base layer and a metal layer formed on at least one surface of the polymer material substrate. The composite current collector may be formed by forming a metal material (copper, copper alloy, nickel, nickel alloy, titanium, titanium alloy, silver and silver alloy, etc.) on a polymer material substrate (such as a substrate of polypropylene (PP), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polystyrene (PS), polyethylene (PE), etc.).

[0114] In some embodiments, the negative electrode active material may adopt the negative electrode active material for the battery known in the art. As an example, the negative electrode active material may include at least one of the following materials: artificial graphite, natural graphite, soft carbon, hard carbon, silicon-based materials, tin-based materials, lithium titanate, etc. The silicon-based material may be selected from at least one of elemental silicon, silicon oxide compounds, silicon-carbon composites, silicon-nitrogen composites, and silicon alloys. The tin-based material may be selected from at least one of elemental tin, tin oxide compounds, and tin alloys. However, the present application is not limited to these materials, and other traditional materials that can be used as negative electrode active materials for batteries may also be used. These negative electrode active materials may be used alone or in combination of two or more.

[0115] In some embodiments, the negative electrode film layer may further include a binder. The binder may be selected from at least one of styrene-butadiene rubber (SBR), polyacrylic acid (PAA), sodium polyacrylate (PAAS), polyacrylamide (PAM), polyvinyl alcohol (PVA), sodium alginate (SA), polymethacrylic acid (PMAA) and carboxymethyl chitosan (CMCS).

[0116] In some embodiments, the negative electrode film layer may further include a conductive agent, which may be selected from at least one of superconducting carbon, acetylene black, carbon black, Ketjen black, carbon dots, carbon nanotubes, graphene and carbon nanofibers.

[0117] In some embodiments, the negative electrode film layer may optionally include other additives, such as a thickener (eg, sodium carboxymethyl cellulose (CMC-Na)).

[0118] In some embodiments, the negative electrode sheet can be prepared in the following manner: the components for preparing the negative electrode sheet, such as the negative electrode active material, the conductive agent, the binder and any other components are dispersed in a solvent (such as deionized water) to form a negative electrode slurry; the negative electrode slurry is coated on the negative electrode collector, and after drying, cold pressing and other processes, the negative electrode sheet can be obtained.

[0119] [Electrolytes]

[0120] The electrolyte plays the role of conducting ions between the positive electrode and the negative electrode. The present application has no specific restrictions on the type of electrolyte, which can be selected according to needs. For example, the electrolyte can be liquid, gel or all-solid.

[0121] In some embodiments, the electrolyte is an electrolyte solution, which includes an electrolyte salt and a solvent.

[0122] In some embodiments, the electrolyte salt can be selected from at least one of lithium hexafluorophosphate, lithium tetrafluoroborate, lithium perchlorate, lithium hexafluoroarsenate, lithium bis(fluorosulfonyl)imide, lithium bis(trifluoromethanesulfonyl)imide, lithium trifluoromethanesulfonate, lithium difluorophosphate, lithium difluorooxalatoborate, lithium dioxalatoborate, lithium difluorodioxalatophosphate, and lithium tetrafluorooxalatophosphate.

[0123] In some embodiments, the solvent can be selected from at least one of ethylene carbonate, propylene carbonate, ethyl methyl carbonate, diethyl carbonate, dimethyl carbonate, dipropyl carbonate, methyl propyl carbonate, ethyl propyl carbonate, butylene carbonate, fluoroethylene carbonate, methyl formate, methyl acetate, ethyl acetate, propyl acetate, methyl propionate, ethyl propionate, propyl propionate, methyl butyrate, ethyl butyrate, 1,4-butyrolactone, cyclopentane sulfone, dimethyl sulfone, methyl ethyl sulfone and diethyl sulfone.

[0124] In some embodiments, the electrolyte may further include additives, such as negative electrode film-forming additives, positive electrode film-forming additives, and additives that can improve certain battery properties, such as additives that improve battery overcharge performance, additives that improve battery high or low temperature performance, etc.

[0125] [Isolation film]

[0126] In some embodiments, the secondary battery further includes a separator. The present application has no particular limitation on the type of separator, and any known porous separator with good chemical stability and mechanical stability can be selected.

[0127] In some embodiments, the material of the isolation membrane can be selected from at least one of glass fiber, non-woven fabric, polyethylene, polypropylene and polyvinylidene fluoride. The isolation membrane can be a single-layer film or a multi-layer composite film, without particular limitation. When the isolation membrane is a multi-layer composite film, the materials of each layer can be the same or different, without particular limitation.

[0128] In some embodiments, the positive electrode sheet, the negative electrode sheet, and the separator may be formed into an electrode assembly by a winding process or a lamination process.

[0129] In some embodiments, the secondary battery may include an outer package, which may be used to encapsulate the electrode assembly and the electrolyte.

[0130] In some embodiments, the outer packaging of the secondary battery may be a hard shell, such as a hard plastic shell, an aluminum shell, a steel shell, etc. The outer packaging of the secondary battery may also be a soft package, such as a bag-type soft package. The material of the soft package may be plastic, and examples of the plastic include polypropylene, polybutylene terephthalate, and polybutylene succinate.

[0131] The present application has no particular limitation on the shape of the secondary battery, which may be cylindrical, square or any other shape. Figure 2 The secondary battery 5 is a square structure as an example.

[0132] In some embodiments, reference Figure 3 , the outer packaging may include a shell 51 and a cover plate 53. Among them, the shell 51 may include a bottom plate and a side plate connected to the bottom plate, and the bottom plate and the side plate enclose a receiving cavity. The shell 51 has an opening connected to the receiving cavity, and the cover plate 53 can be covered on the opening to close the receiving cavity. The positive electrode sheet, the negative electrode sheet and the isolation membrane can form an electrode assembly 52 through a winding process or a lamination process. The electrode assembly 52 is encapsulated in the receiving cavity. The electrolyte is infiltrated in the electrode assembly 52. ​​The number of electrode assemblies 52 contained in the secondary battery 5 can be one or more, and those skilled in the art can select according to specific actual needs.

[0133] In some embodiments, secondary batteries may be assembled into a battery module. The number of secondary batteries contained in the battery module may be one or more, and the specific number may be selected by those skilled in the art according to the application and capacity of the battery module.

[0134] Figure 4 4 is an example of a battery module. Figure 4In the battery module 4, the plurality of secondary batteries 5 may be arranged in sequence along the length direction of the battery module 4. Of course, they may also be arranged in any other manner. Further, the plurality of secondary batteries 5 may be fixed by fasteners.

[0135] Optionally, the battery module 4 may further include a housing having a receiving space, and the plurality of secondary batteries 5 are received in the receiving space.

[0136] In some embodiments, the battery modules described above may also be assembled into a battery pack. The battery pack may contain one or more battery modules, and the specific number may be selected by those skilled in the art according to the application and capacity of the battery pack.

[0137] Figure 5 and Figure 6 1 is a battery pack 1 as an example. Figure 5 and Figure 6 The battery pack 1 may include a battery box and a plurality of battery modules 4 disposed in the battery box. The battery box includes an upper box body 2 and a lower box body 3. The upper box body 2 can cover the lower box body 3 and form a closed space for accommodating the battery modules 4. The plurality of battery modules 4 can be arranged in the battery box in any manner.

[0138] In addition, the present application also provides an electrical device, which includes at least one of the secondary battery, battery module, or battery pack provided in the present application. The secondary battery, battery module, or battery pack can be used as a power source for the electrical device, and can also be used as an energy storage unit for the electrical device. The electrical device may include mobile devices (such as mobile phones, laptops, etc.), electric vehicles (such as pure electric vehicles, hybrid electric vehicles, plug-in hybrid electric vehicles, electric bicycles, electric scooters, electric golf carts, electric trucks, etc.), electric trains, ships and satellites, energy storage systems, etc., but are not limited thereto.

[0139] As the electrical device, a secondary battery, a battery module or a battery pack may be selected according to its usage requirements.

[0140] Figure 7 The power consumption device is taken as an example. The power consumption device is a pure electric vehicle, a hybrid electric vehicle, or a plug-in hybrid electric vehicle. In order to meet the high power and high energy density requirements of the power consumption device for the secondary battery, a battery pack or a battery module can be used.

[0141] Another example of a device may be a mobile phone, a tablet computer, a notebook computer, etc. Such a device is usually required to be thin and light, and a secondary battery may be used as a power source.

[0142] Example 1

[0143] 52 parts by mass of LiNi 0.8 Co 0.1 Mn 0.1 O2 core, 20 parts by weight of ammonium polyphosphate, 3 parts by weight of γ-aminopropyltrimethoxysilane, 10 parts by weight of H2PO4C6H5, 1 part by weight of vanadium pentoxide, and 500 parts by weight of N,N-dimethylformamide were mixed evenly and reacted at 75°C for 10 hours. The mixture was washed and dried to obtain a positive electrode material.

[0144] Example 2

[0145] The positive electrode material of Example 2 was prepared in the same manner as Example 1, except that γ-aminopropyltrimethoxysilane in the raw material was replaced with ethanolamine as shown in Table 1 below.

[0146] Example 3

[0147] The positive electrode material of Example 3 was prepared in the same manner as Example 1, except that the γ-aminopropyltrimethoxysilane in the raw material was replaced with acrylatetrimethoxysilane as shown in Table 1 below.

[0148] Example 4

[0149] The positive electrode material of Example 4 was prepared in the same manner as Example 1, except that H2PO4C6H5 in the raw material was replaced with H2PO4CH3 as shown in Table 1 below.

[0150] Embodiment 5-8

[0151] The positive electrode materials of Examples 5 to 8 were prepared in the same manner as in Example 1, except that the values ​​of m and n were adjusted by adjusting the raw material input amounts as shown in Table 1 below.

[0152] Examples 9-10

[0153] The positive electrode materials of Examples 9-10 were prepared in the same manner as in Example 1, except that the coverage of the flame retardant coating layer was adjusted by adjusting the raw material input amount as shown in Table 1 below.

[0154] Embodiment 11

[0155] The positive electrode material of Example 11 was prepared in the same manner as in Example 1, except that the BET specific surface area of ​​the flame retardant coating layer was adjusted by adjusting the raw material input ratio as shown in Table 1 below.

[0156] Examples 12-13

[0157] The positive electrode materials of Examples 12-13 were prepared in the same manner as in Example 1, except that the thickness of the flame retardant coating layer was adjusted by adjusting the raw material input amount as shown in Table 1 below.

[0158] Comparative Example 1

[0159] Direct use of LiNi 0.8 Co 0.1 Mn 0.1 O2 is used as the positive electrode material.

[0160] Comparative Example 2

[0161] The positive electrode material of Comparative Example 2 was prepared in the same manner as in Example 1, except that γ-aminopropyltrimethoxysilane and H2PO4C6H5 were not added as shown in Table 1 below.

[0162] Comparative Example 3

[0163] A positive electrode material of Comparative Example 3 was prepared in the same manner as Example 1, except that ammonium polyphosphate was not added as shown in Table 1 below.

[0164] The characteristic parameters of the positive electrode materials involved in Examples 1-13 and Comparative Examples 1-3 are shown in Table 1.

[0165] Table 1 Characteristic parameters of positive electrode materials

[0166]

[0167] In addition, the positive electrode materials obtained in the above Examples 1-13 and Comparative Examples 1-3 were respectively prepared into secondary batteries as shown below and the performance tests were performed.

[0168] (1) Preparation of secondary batteries

[0169] The finished positive electrode materials in the above-mentioned embodiments and comparative examples were used as positive electrode materials, and were thoroughly stirred and mixed with conductive agent acetylene black and binder polyvinylidene fluoride (PVDF) in an N-methylpyrrolidone solvent system at a weight ratio of 94:3:3, and then coated on aluminum foil, dried, and cold pressed to obtain a positive electrode sheet.

[0170] Artificial graphite as a negative electrode active material, acetylene black as a conductive agent, styrene butadiene rubber (SBR) as a binder, and carbon methyl cellulose sodium (CMC) as a thickener are fully stirred and mixed in a deionized water solvent system in 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.

[0171] A porous polymer film made of polyethylene (PE) is used as the isolation membrane.

[0172] The positive electrode sheet, the separator and the negative electrode sheet are stacked in order, so that the separator is between the positive and negative electrodes to play a role of isolation, and then wound to obtain a bare cell. The electrolyte is 1mol / L LiPF6 / (ethylene carbonate (EC) + diethyl carbonate (DEC) + dimethyl carbonate (DMC)) (volume ratio 1:1:1). The bare cell is placed in an outer package, injected with the above electrolyte and packaged to obtain a secondary battery.

[0173] (2) Acupuncture experiment

[0174] The secondary battery prepared above was charged at a current of 0.5C to an upper voltage limit of 4.35V, and then charged at a constant voltage at the corresponding cut-off voltage, with a cut-off current of 0.2C. A steel needle with a diameter of 3mm was completely inserted into the center of the battery at a speed of 50mm / s, and the insertion state was maintained for 1 hour or the battery surface temperature dropped to 50°C after thermal runaway occurred, and the test was terminated.

[0175] (3) Hot box test

[0176] The secondary battery prepared above was placed in a drying oven and heated to 160° C. at a heating rate of 5° C. / min and maintained for 30 min.

[0177] (4) Overcharge test

[0178] The secondary battery prepared above was charged to 120% SOC at 0.5C and observed for 1 h.

[0179] (5) 500 cycles of normal pressure retention test

[0180] The secondary battery prepared as above was charged to 4.2V at 1C in a constant temperature environment of 60°C, then charged at a constant voltage at 4.2V to a current ≤0.05C, allowed to stand for 5 minutes, and then discharged to 2.8V at 1C. This cycle was repeated for 500 cycles. The capacity after 500 cycles obtained by the test was divided by the initial capacity to obtain the capacity retention rate.

[0181] The test results are shown in Table 2.

[0182] Table 2 Test results

[0183]

[0184] It can be seen that Example 1 is the best test scheme. Compared with Comparative Examples 1-3, the secondary battery prepared by the positive electrode material of Example 1 can 100% pass the needle puncture test, hot box test and overcharge test, while the battery prepared by the positive electrode material of Comparative Examples 1-3 caught fire and exploded in most cases in all safety tests; moreover, in terms of the 500-cycle cycle retention rate at normal pressure, the battery obtained by the positive electrode material of Example 1 is no different from the battery obtained by Comparative Example 1 without a flame retardant layer, indicating that the flame retardant coating layer of the present application has a good effect on the flame retardancy of the battery and does not affect the 500-cycle cycle retention rate of the battery at normal pressure.

[0185] The thickness of the flame retardant coating layer of Example 12 is half the thickness of the flame retardant coating layer of Example 1. Accordingly, its flame retardant effects in the needle puncture test, hot box test and overcharge test are significantly lower than those of Example 1, indicating that the thickness of the flame retardant coating layer directly affects the flame retardant effect of the battery.

[0186] Example 11 greatly reduces the BET specific surface area of ​​the flame retardant coating in Example 1, resulting in a decrease in the cycle retention rate of the battery at 500 cycles at normal pressure, indicating that the BET specific surface area of ​​the flame retardant coating affects the cycle retention rate of the battery at 500 cycles at normal pressure and therefore cannot be too small.

[0187] The coverage of the flame retardant coating layer of Example 9 is less than half of that of Example 1, resulting in the flame retardant effect of the battery prepared by the obtained positive electrode material in the needle puncture test, hot box test and overcharge test being significantly lower than that of Example 1, indicating that too low coverage of the flame retardant coating layer is not conducive to the flame retardant effect; however, the coverage should not be too high. The flame retardant coating layer of Example 10 adopts a coverage of 100%, but the flame retardant effect of the battery prepared by the positive electrode material in the needle puncture test, hot box test and overcharge test is not as good as that of Example 1. Therefore, the coverage of the flame retardant coating layer should be in an appropriate range to be more conducive to the flame retardant effect.

[0188] The flame retardant raw materials of Example 2 and Example 3 are different. Although neither of them has a good flame retardant effect as the battery prepared with the positive electrode material of Example 1, those skilled in the art can see that different flame retardant raw materials can achieve good flame retardant effects.

[0189] In general, the batteries of Comparative Examples 1 to 3 caught fire and exploded in most cases in all safety tests, while most of the batteries prepared using the positive electrode materials of Examples 1-13 passed the safety tests and had good cycle performance. This is because the flame-retardant coating layer can decompose and produce free radicals at high temperatures, and timely capture the active oxygen released by the positive electrode to prevent the active oxygen from diffusing and spreading in the battery and reacting violently with the combustibles in the battery to cause thermal runaway; it can also form a dense barrier layer on the surface of the positive electrode to prevent the highly oxidizing positive electrode from contacting the electrolyte and the anode, and avoid the heat generated by violent exothermic side reactions such as crosstalk between the positive and negative electrodes, thereby greatly reducing the heat generated by thermal runaway of the battery and significantly improving the safety performance of the battery.

[0190] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them; although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein by equivalents; 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 embodiments of the present application, and they should all be included in the scope of the claims and specification of the present application. In particular, as long as there is no structural conflict, the various technical features mentioned in the various embodiments can be combined in any way. The present application is not limited to the specific embodiments disclosed herein, but includes all technical solutions that fall within the scope of the claims.

Claims

1. A positive electrode material, characterized in that: The invention comprises a core and a flame retardant coating layer coated on the surface of the core, wherein the flame retardant coating layer comprises a polyphosphate ammonium polymer main chain [(PO4NH4)] m , cross-linking region X and phosphate side chain [(PO3Y)] n , the flame retardant coating layer is a polymer represented by formula I: [Formula I] Wherein, the unit structure of the cross-linked region X is [X1-R1-X2], X1 and X2 are independently selected from one of -CH2-, -CH2-O-, -CO-, -COO-, -NH-, and -Si(-O-)3; R1 is C1-C 10 Alkyl, C1-C 10 Aromatic, C1-C 10 One of the polyethers; 10 < m <10000; 1 < n <1000; Y is C1~C 10 Alkyl or C1~C 10 Aromatic group.

2. The material according to claim 1, characterized in that In the chemical structure of the flame retardant coating layer, 200<m<1950, 1<n<100.

3. The material according to claim 1 or 2, characterized in that The coverage rate of the flame retardant coating layer is 40% to 100%.

4. The material according to claim 3, characterized in that The coverage rate of the flame retardant coating layer is 60% to 90%.

5. The material according to claim 1, characterized in that The thickness of the flame retardant coating layer is 10nm~1000nm.

6. The material according to claim 1, characterized in that The thickness of the flame retardant coating layer is 20nm~100nm.

7. The material according to claim 1, characterized in that The specific surface area of ​​the flame retardant coating is 1m 2 / g~100m 2 / g.

8. The material according to claim 1, characterized in that The inner core includes at least one of an olivine-structured lithium-containing phosphate, a lithium transition metal oxide, and their respective modified compounds.

9. The material according to claim 8, characterized in that The core is at least one of lithium cobalt oxide, lithium manganese oxide, lithium nickel oxide, lithium titanium oxide, lithium nickel manganese oxide, and lithium nickel cobalt manganese composite oxide.

10. The material according to claim 9, characterized in that The core is LiFePO4, LiMnPO4, LiCoO2, LiNi 0.6 Co 0.2 Mn 0.2 O2、LiNi 0.8 Co 0.1 Mn 0.1 O2、LiNi 0.9 Co 0.05 Mn 0.05 O2、LiNi 0.8 Co 0.1 Al 0.1 At least one of O2.

11. A method for preparing the material according to any one of claims 1 to 10, characterized in that: The following steps are involved: Providing ammonium polyphosphate and phosphate ester, dispersing the ammonium polyphosphate and the phosphate ester in a solvent, adding a cross-linking agent and a catalyst, and stirring evenly to obtain a flame retardant; processing the flame retardant and the core together to obtain a positive electrode material; The positive electrode material comprises the core and a flame retardant coating layer coated on the surface of the core, wherein the flame retardant coating layer comprises a polyphosphate ammonium polymer main chain [(PO4NH4)] m , cross-linking region X and phosphate side chain [(PO3Y)] n , the flame retardant coating layer is a polymer represented by formula I: [Formula I] Wherein, the unit structure of the cross-linked region X is [X1-R1-X2], X1 and X2 are independently selected from one of -CH2-, -CH2-O-, -CO-, -COO-, -NH-, and -Si(-O-)3; R1 is C1-C 10 Alkyl, C1-C 10 Aromatic, C1-C 10 One of the polyethers; 10 < m <10000; 1 < n <1000; Y is C1~C 10 Alkyl or C1~C 10 Aromatic group.

12. The method according to claim 11, characterized in that The processing includes: The flame retardant and the core are placed in a ball milling jar, and ball milled at a rotation speed of 100 r / min to 800 r / min for 1 h to 24 h to obtain the positive electrode material.

13. The method according to claim 11, characterized in that The processing includes: The flame retardant and the core are dispersed in a solvent, and spray-dried at 80° C. to 200° C. using a spray dryer to obtain the positive electrode material.

14. A secondary battery comprising a positive electrode, a negative electrode, an electrolyte and a separator, characterized in that: The invention comprises the positive electrode material according to any one of claims 1 to 10 or the positive electrode material prepared by the method according to any one of claims 11 to 13.

15. A battery module, characterized in that: Includes the secondary battery as claimed in claim 14.

16. A battery pack, characterized in that: Comprising the battery module as claimed in claim 15.

17. An electrical device, characterized in that: The battery comprises at least one selected from the secondary battery of claim 14, the battery module of claim 15, or the battery pack of claim 16.

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