Nickel cobalt manganese oxide precursor and preparation method and application thereof

Abstract

The invention belongs to the technical field of secondary batteries, and particularly relates to a nickel cobalt manganese oxide precursor and a preparation method and application thereof. According to the nickel cobalt manganese oxide precursor provided by the invention, the specific surface area of the nickel cobalt manganese oxide precursor is 50-150m < 2 > / g, and the pore volume of the nickel cobalt manganese oxide precursor is 0.1-0.5 cm < 3 > / g. Researches find that the specific surface area and the pore volume of the nickel cobalt manganese oxide precursor are limited in a specific range, a more favorable lithium intercalation path can be provided, the reaction activity of a lithium source and the nickel cobalt manganese oxide precursor in the subsequent calcination reaction process is improved, more lithium ions are intercalated into the nickel cobalt lithium manganate material, and the lithium ion battery performance is improved. And the nickel cobalt lithium manganate material with low residual alkali on the surface and excellent electrical performance can be prepared.

Description

Technical Field

[0001] This application belongs to the field of secondary battery technology, specifically relating to a nickel-cobalt-manganese oxide precursor, its preparation method, and its application. Background Technology

[0002] High-temperature solid-state methods are the most common industrial approach for preparing lithium nickel cobalt manganese oxide (LiCO) cathode materials. However, the low reactivity of the hydroxide precursor and lithium source leads to high residual alkali on the surface of the cathode material, thus affecting its electrical performance. Furthermore, due to the low reactivity of Ni... 2+ and Li + Because they have similar ionic radii, cation mixing occurs. Therefore, it is necessary to increase the oxygen partial pressure during sintering, or even use pure oxygen, to oxidize the divalent nickel in the material to trivalent nickel. The use of high temperature and oxygen not only increases the difficulty of operation and the safety hazards of the entire process, but also causes a large amount of lithium source to volatilize, resulting in increased economic costs.

[0003] Currently, existing technologies have published some solutions to these problems. For example, one method involves oxidizing the precursor with H2O2 and sintering the cathode material in air. However, the decomposition of H2O2 itself makes it difficult to guarantee the stability of oxidation in industrial applications, and H2O2 reacts with ammonia to form an explosive gas, increasing the risk of the reaction. Therefore, how to stably improve the reactivity of the precursor and lithium salt in the subsequent calcination process through a simple method, and thus prepare lithium nickel cobalt manganese oxide cathode materials with low surface residual alkali and excellent electrochemical performance, is of great interest. Summary of the Invention

[0004] This application provides a nickel-cobalt-manganese oxide precursor, its preparation method, and its application, in order to solve the problems in the prior art such as low reactivity of nickel-cobalt-manganese precursors with lithium sources, high residual alkali on the surface of the material, and the need for further improvement in electrochemical performance.

[0005] In a first aspect, this application provides a nickel-cobalt-manganese oxide precursor, wherein the specific surface area of ​​the nickel-cobalt-manganese oxide precursor is 50-150 m². 2 / g, pore volume 0.1-0.5cm³ 3 / g.

[0006] In some optional embodiments, the specific surface area of ​​the nickel-cobalt-manganese oxide precursor is 70-150 m². 2 / g, pore volume 0.15-0.45cm³ 3 / g.

[0007] Secondly, this application also provides a method for preparing the above-mentioned nickel-cobalt-manganese oxide precursor, comprising the following steps:

[0008] S1, sintering nickel cobalt manganese hydroxide at 480℃~650℃ for 30min~150min;

[0009] S2, after sintering, is cooled at an average cooling rate of 20-30℃ / min to obtain nickel cobalt manganese oxide precursor.

[0010] In some optional embodiments, in step S1, the sintering temperature is 550℃~650℃ and the sintering time is 40min~60min;

[0011] And / or, in step S1, the sintering atmosphere is an oxygen-containing atmosphere, or optionally, the sintering atmosphere is an air atmosphere;

[0012] And / or, in step S2, the average cooling rate is 25–30 °C / min;

[0013] And / or, in step S2, the temperature is lowered to below 40°C.

[0014] Thirdly, this application provides a method for preparing lithium nickel cobalt manganese oxide material, comprising the following steps:

[0015] S11, the lithium source is mixed with the nickel cobalt manganese oxide precursor provided in the first aspect of this application or the nickel cobalt manganese oxide precursor prepared by the preparation method provided in the second aspect of this application to obtain a mixture;

[0016] S12, the mixture is calcined to obtain lithium nickel cobalt manganese oxide material.

[0017] In some optional embodiments, in step S11, the molar ratio of the lithium source to all metal elements in the nickel cobalt manganese oxide precursor is 1.01 to 1.05, and optionally 1.01 to 1.03.

[0018] And / or, in step S12, the calcination temperature is 790℃~940℃, and the calcination time is 7~13h, optionally 7~9h;

[0019] And / or, in step S12, the heating rate of the calcination step is 1.5-7℃ / min;

[0020] And / or, in step S12, calcination is carried out in a roller kiln, with the height of the kiln being 5-8 cm, optionally 7-8 cm;

[0021] And / or, in step S12, the calcination atmosphere is an oxygen-containing atmosphere, or optionally, the calcination atmosphere is an air atmosphere.

[0022] Fourthly, this application provides a lithium nickel cobalt manganese oxide material, which is prepared by the preparation method provided in the third aspect of this application.

[0023] Fifthly, this application provides a positive electrode sheet, comprising:

[0024] Positive current collector, and

[0025] A positive electrode active material layer disposed on at least one side of the positive electrode current collector, the positive electrode active material layer including the lithium nickel cobalt manganese oxide material provided in the fourth aspect of this application.

[0026] Sixthly, this application provides a secondary battery, including the positive electrode provided in the fifth aspect of this application.

[0027] In a seventh aspect, this application provides an electrical device, including the secondary battery provided in the sixth aspect of this application.

[0028] The technical solution of this application has the following advantages:

[0029] The nickel-cobalt-manganese oxide precursor provided in this application has a specific surface area of ​​50-150 m². 2 / g, pore volume 0.1-0.5cm³ 3 / g. This application has found that limiting the specific surface area and pore volume of the nickel cobalt manganese oxide precursor to a specific range can provide a more favorable lithium intercalation pathway, enhance the reactivity of the lithium source and the nickel cobalt manganese oxide precursor in the subsequent calcination reaction, and enable more lithium ions to be intercalated into the lithium nickel cobalt manganese oxide material, thereby enabling the preparation of lithium nickel cobalt manganese oxide materials with low surface residual alkali and excellent electrical properties.

[0030] The nickel-cobalt-manganese oxide precursor provided in this application has a specific surface area of ​​70-150 m². 2 / g, pore volume 0.15-0.45cm³ 3 / g. This application increases the effective contact area between the precursor and the lithium source by further limiting the specific surface area and pore volume of the nickel cobalt manganese oxide precursor without damaging the precursor particles, thereby obtaining a nickel cobalt manganese oxide precursor with optimal reactivity.

[0031] The method for preparing nickel cobalt manganese oxide precursor provided in this application includes the following steps: S1, sintering nickel cobalt manganese hydroxide at 480℃~650℃ for 30min~150min; S2, after sintering, cooling at an average cooling rate of 20~30℃ / min to obtain the nickel cobalt manganese oxide precursor. This application achieves this by sintering nickel cobalt manganese hydroxide at a specific temperature for a certain time, which forms pores. Rapid cooling then prevents pore closure, thus obtaining a nickel cobalt manganese oxide precursor with a large specific surface area and pore volume. This method does not require the addition of pore-expanding materials or pore-forming agents, is simple to operate, and is easy to promote and apply.

[0032] The method for preparing nickel cobalt manganese oxide precursor provided in this application, through optimization of sintering temperature, sintering time and average cooling rate, yields lithium nickel cobalt manganese oxide cathode material with better electrochemical performance and lower surface residual alkali.

[0033] The preparation method of lithium nickel cobalt manganese oxide material provided in this application includes the following steps: S11, mixing a lithium source with the aforementioned nickel cobalt manganese oxide precursor or the nickel cobalt manganese oxide precursor prepared by the aforementioned preparation method to obtain a mixture; S12, calcining the mixture to obtain lithium nickel cobalt manganese oxide material. This application utilizes the nickel cobalt manganese oxide precursor provided in this application, which, due to its porous structure, provides a more favorable lithium intercalation pathway, enhancing the reactivity of the lithium source and the nickel cobalt manganese oxide precursor in the subsequent calcination reaction, thereby preparing a lithium nickel cobalt manganese oxide material with low surface residual alkali and excellent electrochemical performance.

[0034] The method for preparing lithium nickel cobalt manganese oxide (LCO) provided in this application allows for lower calcination temperatures and times due to the high reactivity of the lithium source and the nickel cobalt manganese oxide precursor during the subsequent calcination reaction. This reduces lithium source volatilization, allows for a lower lithium ratio, and lowers energy consumption and economic costs. Furthermore, the lower lithium ratio and more favorable lithium intercalation pathways enable more lithium ions to be effectively embedded within the LCO material, further reducing residual alkali on the material surface.

[0035] The secondary battery provided in this application has a positive electrode active material layer comprising the aforementioned lithium nickel cobalt manganese oxide material, which enables the secondary battery to have lower internal resistance (DCR) and better discharge and cycle performance. Attached Figure Description

[0036] To more clearly illustrate the technical solutions in the specific embodiments of this application or the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0037] Figure 1 This is an electron microscope cross-sectional view of the nickel cobalt manganese oxide precursor provided in Example 2 of this application;

[0038] Figure 2 This is an electron microscope cross-sectional view of the nickel cobalt manganese oxide precursor provided in Example 4 of this application;

[0039] Figure 3 This is an electron microscope cross-sectional view of the nickel-cobalt-manganese hydroxide used in Comparative Example 1 of this application;

[0040] Figure 4This is an electron microscope cross-sectional view of the nickel-cobalt-manganese oxide precursor provided in Comparative Example 5 of this application. Detailed Implementation

[0041] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of the embodiments. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.

[0042] 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 pertains; the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the application; the terms “comprising” and “having”, and any variations thereof, in the specification and claims of this application are intended to cover non-exclusive inclusion.

[0043] In the description of the embodiments of this application, technical terms such as "first" and "second" are used only to distinguish different objects and should not be construed as indicating or implying relative importance or implicitly indicating the number, specific order, or primary and secondary relationship of the indicated technical features.

[0044] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0045] The "range" disclosed in this application is defined by a lower limit and an upper limit. A given range is defined by selecting a lower limit and an upper limit, which define the boundaries of a particular range. Ranges defined in this way can include or exclude endpoints and can be arbitrarily combined; that is, any lower limit can be combined with any upper limit to form a range. For example, if ranges of 60-120 and 80-110 are listed for a specific parameter, it is expected that ranges of 60-110 and 80-120 are also included. Furthermore, if minimum range values ​​of 1 and 2 are listed, and if maximum range values ​​of 3, 4, and 5 are listed, then the following ranges are all expected: 1-3, 1-4, 1-5, 2-3, 2-4, and 2-5. In this application, unless otherwise stated, the numerical range "ab" represents a shortened representation of any combination of real numbers between a and b, where a and b are real numbers. For example, the numerical range "0-5" indicates that all real numbers between "0-5" have been listed in this article; "0-5" is simply a shortened representation of these numerical combinations. Furthermore, when a parameter is stated as an integer ≥2, it is equivalent to disclosing that the parameter is, for example, an integer such as 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, etc.

[0046] In the description of the embodiments in this application, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, and B existing alone. Additionally, the character " / " in this document generally indicates that the preceding and following related objects have an "or" relationship.

[0047] In the description of the embodiments of this application, the term "multiple" refers to two or more (including two), similarly, "multiple sets" refers to two or more (including two sets), and "multiple pieces" refers to two or more (including two pieces).

[0048] In the description of the embodiments of this application, unless otherwise expressly specified and limited, technical terms such as "installation," "connection," "joining," and "fixing" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. For those skilled in the art, the specific meaning of the above terms in the embodiments of this application can be understood according to the specific circumstances.

[0049] To address the problems of low reactivity of nickel-cobalt-manganese precursors with lithium sources, high residual alkali on the surface of materials, and the need for further improvement in electrochemical performance in existing technologies, according to the first aspect of this application, a nickel-cobalt-manganese oxide precursor is provided, wherein the specific surface area of ​​the nickel-cobalt-manganese oxide precursor is 50-150 m².2 / g, pore volume 0.1-0.5cm³ 3 / g. This application, through research, discovered that limiting the specific surface area and pore volume of the nickel cobalt manganese oxide precursor within a specific range can provide a more favorable lithium intercalation pathway, enhance the reactivity of the lithium source and the nickel cobalt manganese oxide precursor in the subsequent calcination reaction, and allow more lithium ions to be intercalated into the lithium nickel cobalt manganese oxide material. This results in the preparation of lithium nickel cobalt manganese oxide materials with low surface alkali residue and excellent electrical properties. If the specific surface area and pore volume of the nickel cobalt manganese oxide precursor are too low, the material's reactivity is low, the lithium intercalation reaction rate is slow, and the reaction temperature requirement is higher. At high temperatures, a large amount of lithium source that fails to react in time volatilizes, leading to a low lithium content and poor electrochemical performance in the material. Conversely, if the specific surface area and pore volume of the nickel cobalt manganese oxide precursor are too high, the precursor will undergo excessive volume expansion and contraction, resulting in through-cracks. This will lead to electrolyte infiltration during application, triggering a series of side reactions and affecting the material's cycle stability.

[0050] In some optional embodiments, the specific surface area of ​​the nickel-cobalt-manganese oxide precursor can be 50 m². 2 / g, 55m 2 / g, 60m 2 / g, 70m 2 / g, 80m 2 / g, 90m 2 / g, 100m 2 / g, 120m 2 / g, 130m 2 / g, 140m 2 / g, 150m 2 / g, or within any range of the above values; pore volume can be 0.1cm³. 3 / g, 0.15cm 3 / g, 0.2cm 3 / g, 0.26cm 3 / g, 0.31cm 3 / g, 0.37cm 3 / g, 0.43cm 3 / g, 0.48cm 3 / g, 0.5cm 3 / g, or within any of the above values.

[0051] In some optional embodiments, the specific surface area of ​​the nickel-cobalt-manganese oxide precursor is 70-150 m². 2 / g, pore volume 0.15-0.45cm³ 3 / g. This application, by further limiting the specific surface area and pore volume of the nickel cobalt manganese oxide precursor, increases the effective contact area between the precursor and the lithium source without damaging the precursor particles, thus obtaining a nickel cobalt manganese oxide precursor with optimal reactivity. Compared with the untreated precursor, the nickel cobalt manganese oxide precursor with a large specific surface area can be adapted to lower calcination temperatures and times in subsequent calcination processes, thereby reducing lithium source volatilization and lowering the lithium ratio. Lower lithium source volatilization and efficient lithium-ion intercalation processes are beneficial for obtaining lithium nickel cobalt manganese oxide materials with low surface residual alkali, resulting in lower internal resistance (DCR) and better discharge and cycle performance in secondary batteries.

[0052] According to a second aspect of this application, a method for preparing a nickel-cobalt-manganese oxide precursor is provided, comprising the following steps: S1, sintering nickel-cobalt-manganese hydroxide at 480℃~650℃ for 30min~150min; S2, after sintering, cooling at an average cooling rate of 20~30℃ / min to obtain the nickel-cobalt-manganese oxide precursor. This application obtains a nickel-cobalt-manganese oxide precursor with a large specific surface area and pore volume by sintering nickel-cobalt-manganese hydroxide at a specific temperature for a certain time to form pores, and then rapidly cooling to prevent pore closure. This method does not require the addition of pore-expanding materials or pore-forming agents, is simple to operate, and is easy to promote and apply. If the sintering temperature is too low or the sintering time is too short, the dehydration reaction of the precursor will be incomplete, resulting in fewer pores and making it impossible to obtain a nickel cobalt manganese oxide precursor with a large specific surface area and pore volume. Furthermore, the sintering rate in the subsequent calcination process will be greatly reduced. If the sintering time is too long, the pores will be closed after the precursor dehydration is completed, and even rapid cooling will not yield a nickel cobalt manganese oxide precursor with a large specific surface area and pore volume. If the sintering temperature is too high, the precursor will begin to crystallize and form primary grains, which will hinder the subsequent lithium intercalation process and increase the lithium ion insertion / extraction pathway in the lithium nickel cobalt manganese oxide cathode material, which is detrimental to the electrochemical performance. If the average cooling rate is too slow, the pores formed during the sintering process will partially close, thus failing to obtain a nickel cobalt manganese oxide precursor with a large specific surface area and pore volume.

[0053] In some alternative embodiments, the sintering temperature can be 480°C, 500°C, 520°C, 540°C, 550°C, 570°C, 590°C, 600°C, 630°C, 650°C, or within any range of the above values; the sintering time can be 30 min, 50 min, 75 min, 88 min, 95 min, 110 min, 120 min, 135 min, 145 min, 150 min, or within any range of the above values; the average cooling rate can be 20°C / min, 22°C / min, 25°C / min, 27°C / min, 30°C / min, or within any range of the above values.

[0054] In this application, the cooling time of the material is controlled by controlling the mass ratio of the material to the cooling water, thereby achieving the regulation of the average cooling rate.

[0055] In some optional embodiments, in step S1, the sintering temperature is 550℃~650℃ and the sintering time is 40min~60min; and / or, in step S1, the sintering atmosphere is an oxygen-containing atmosphere, optionally, the sintering atmosphere is an air atmosphere; and / or, in step S2, the average cooling rate is 25~30℃ / min; and / or, in step S2, the temperature is lowered to below 40℃.

[0056] The method for preparing nickel cobalt manganese oxide precursor provided in this application, by optimizing the sintering temperature, sintering time and average cooling rate, interrupts the pore closure process after the precursor dehydration, resulting in a nickel cobalt manganese oxide precursor with a larger surface area and pore volume and better reactivity. Due to the increased reactivity, the precursor can be adapted to lower calcination temperature and calcination time, thereby reducing the loss of lithium source volatilization and reducing the lithium ratio. The high reactivity and low lithium source volatilization enable lithium ions to be more effectively embedded in the precursor, thereby obtaining a ternary cathode material with low surface residual alkali, resulting in a secondary battery with lower internal resistance (DCR) and better discharge and cycle performance.

[0057] In this application, the composition and preparation method of the nickel-cobalt-manganese hydroxide are conventional in the art. In some optional embodiments, the composition of the nickel-cobalt-manganese hydroxide is Ni x Co y Mn (1-x-y) (OH)₂, 0.5≤x≤0.8, 0.05≤y≤0.2, for example, Ni 0.5 Co 0.2 Mn 0.3 (OH)2, Ni 0.6 Co 0.2 Mn 0.2 (OH)2, Ni 0.7 Co 0.15 Mn 0.15 (OH)2.

[0058] This application does not exclude other methods for preparing nickel-cobalt-manganese oxide precursors with corresponding specific surface area and pore volume, such as the existing technology of adding pore-expanding materials or pore-forming agents. However, the preparation method provided in this application does not require the introduction of external substances, the method is simpler, and the adverse effects of these substances on the material properties can be avoided.

[0059] According to a third aspect of this application, a method for preparing lithium nickel cobalt manganese oxide material is provided, comprising the following steps: S11, mixing a lithium source with the above-mentioned nickel cobalt manganese oxide precursor or the nickel cobalt manganese oxide precursor prepared by the above-mentioned preparation method to obtain a mixture; S12, calcining the mixture to obtain lithium nickel cobalt manganese oxide material.

[0060] This application utilizes the nickel cobalt manganese oxide precursor provided in this application. Due to its porous structure, it can provide a more favorable lithium intercalation pathway, thereby enhancing the reactivity of the lithium source and the nickel cobalt manganese oxide precursor in the subsequent calcination reaction process, and thus preparing a lithium nickel cobalt manganese oxide material with low surface residual alkali and excellent electrochemical performance.

[0061] In some optional embodiments, in step S11, the molar ratio (also known as the lithium ratio) of all metal elements in the lithium source and the nickel-cobalt-manganese oxide precursor is 1.01 to 1.05, optionally 1.01 to 1.03; and / or, in step S12, the calcination temperature is 790℃ to 940℃, and the calcination time is 7 to 13 hours, optionally 7 to 9 hours; and / or, in step S12, the heating rate of the calcination step is 1.5-7℃ / min; and / or, in step S12, the calcination is carried out in a roller kiln, and the height of the calcined pot is 5 to 8 cm, optionally 7 to 8 cm; and / or, in step S12, the calcination atmosphere is an oxygen-containing atmosphere, optionally an air atmosphere.

[0062] In this application, because the lithium source and nickel-cobalt-manganese oxide precursor exhibit high reactivity during the subsequent calcination reaction, lower calcination temperatures and times can be accommodated, thereby reducing lithium source volatilization, allowing for a lower lithium ratio, and lowering energy consumption and economic costs. Furthermore, the lower lithium ratio, coupled with a more favorable lithium intercalation pathway, enables more lithium to be embedded within the lithium nickel-cobalt-manganese oxide material, further reducing residual alkali on the material surface. This application, by limiting calcination in a roller kiln and restricting the loading height and heating rate, yields a lithium nickel-cobalt-manganese oxide cathode material with superior electrochemical performance. If the calcination temperature is too low or the calcination time is too short, problems such as incomplete lithium intercalation and incomplete crystal structure growth will occur, which will hinder lithium ion intercalation and deintercalation. If the calcination temperature is too high or the calcination time is too long, the primary grains will be too large, the ion diffusion path will be extended, which will hinder lithium ion intercalation and deintercalation during battery discharge and thus affect battery performance. If the pot height is too low, the material will be too thin, and the specific surface area in contact with the gas will be larger, which will lead to serious problems of lithium source volatilization. If the pot height is too high, the material temperature difference between different heights will be large due to poor solid heat transfer, and the uniformity of calcined material will be poor.

[0063] In some optional embodiments, the molar ratio of the lithium source to all metal elements in the nickel-cobalt-manganese oxide precursor can be 1.01, 1.02, 1.03, 1.04, 1.05, or within any range of the above values; the calcination temperature can be 790℃, 820℃, 850℃, 870℃, 890℃, 900℃, 910℃, 915℃, 920℃, 930℃, 940℃, or within any range of the above values; the calcination time can be 7h, 8h, 9h, 10h, 11h, 12h, 13h, or within any range of the above values; the heating rate of the calcination step can be 4℃ / min, or within any range of the above values; the height of the container can be 5cm, 5.5cm, 6cm, 6.5cm, 7cm, 7.5cm, 8cm, or within any range of the above values.

[0064] In this application, the lithium source is conventional in the field, and in some optional embodiments, it can be at least one of lithium carbonate, lithium hydroxide, lithium oxide, etc.

[0065] According to a fourth aspect of this application, a lithium nickel cobalt manganese oxide material is also provided, which is prepared by the above-described preparation method.

[0066] According to a fifth aspect of this application, a positive electrode sheet is provided, comprising:

[0067] Positive current collector, and

[0068] A positive electrode active material layer disposed on at least one side of the positive electrode current collector, the positive electrode active material layer comprising the aforementioned lithium nickel cobalt manganese oxide material.

[0069] According to a sixth aspect of this application, a secondary battery is provided, comprising the aforementioned positive electrode.

[0070] According to a seventh aspect of this application, an electrical device is provided, comprising the aforementioned secondary battery.

[0071] The following describes the secondary battery and electrical equipment of this application.

[0072] Typically, a secondary battery consists of a positive electrode, a negative electrode, an electrolyte, and a separator. During charging and discharging, active ions move back and forth between the positive and negative electrodes, inserting and releasing. The electrolyte acts as a conductor between the positive and negative electrodes. The separator, positioned between the positive and negative electrodes, primarily prevents short circuits while allowing ions to pass through.

[0073] [Positive electrode plate]

[0074] The positive electrode plate includes a positive electrode current collector and a positive electrode active material layer provided on at least one surface of the positive electrode current collector, and the positive electrode active material layer includes the lithium nickel cobalt manganese oxide material of the fourth aspect of the present application.

[0075] As an example, the positive electrode current collector has two surfaces opposite to each other in its own thickness direction, and the positive electrode active material layer is provided on any one or both of the two opposite surfaces of the positive electrode current collector.

[0076] The positive electrode active material layer includes a positive electrode active material. The positive electrode active material can be selected from materials that can absorb and release lithium.

[0077] In some embodiments, the positive electrode active material layer in the positive electrode plate of the present application does not exclude other positive electrode active materials other than the lithium nickel cobalt manganese oxide material provided by the present application. For example, other positive electrode active materials can adopt positive electrode active materials well-known in the art for batteries. The specific type of the positive electrode active material is not specifically limited and can be selected according to requirements. As an example, the positive electrode active material can include, but is not limited to, lithium iron phosphate (LiFePO4), lithium manganese phosphate (LiMnPO4), lithium cobalt phosphate (LiCoPO4), lithium iron pyrophosphate (Li2FeP2O7), lithium cobalt oxide (LiCoO2), spinel-type lithium manganese oxide (LiMn2O4), spinel-type lithium nickel manganese oxide (LiNi 0.5 Mn 1.5 O4), layered lithium manganese oxide (LiMnO2), lithium nickel oxide (LiNiO2), lithium niobate (LiNbO2), lithium ferrite (LiFeO2), lithium manganate (LiMgO2), lithium calcium oxide (LiCaO2), lithium copper oxide (LiCuO2), lithium zinc oxide (LiZnO2), lithium molybdate (LiMoO2), lithium tantalate (LiTaO2), lithium tungstate (LiWO2), lithium nickel cobalt aluminum oxide (LiNi x Co y Al 1-x-y O2, 0 < x < 1, 0 < y < 1, 0 < x + y < 1, such as LiNi 0.8 Co 0.15 Al 0.05 O2), lithium nickel cobalt manganese oxide (LiNi x Co y Mn 1-x-y O2, 0 < x < 1, 0 < y < 1, 0 < x + y < 1, such as LiNi 1 / 3 Co 1 / 3 Mn 1 / 3 O2, LiNi 0.5 Co 0.2 Mn 0.3 O2, LiNi 0.6 Co 0.2 Mn 0.2O2, LiNi 0.8 Co 0.1 Mn 0.1 At least one of the following: O2, lithium-rich materials (e.g., lithium-rich nickel-cobalt-manganese oxide), manganese oxide (MnO2), vanadium oxide, sulfur oxide, silicate oxide, and their respective modified compounds. These materials may be used alone or in combination of two or more.

[0078] The modified compounds for the above-mentioned positive electrode active materials can be modified by doping, surface coating, or both doping and coating.

[0079] In some embodiments, the positive current collector may be a metal foil or a composite current collector. For example, aluminum foil may be used as the metal foil. The composite current collector may include a polymer substrate and a metal layer formed on at least one surface of the polymer substrate. The composite current collector may be formed by forming a metal material (aluminum, aluminum alloy, nickel, nickel alloy, titanium, titanium alloy, silver and silver alloy, etc.) on a polymer substrate (such as a substrate of polypropylene (PP), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polystyrene (PS), polyethylene (PE), etc.).

[0080] In some embodiments, the positive electrode active material layer may optionally include a binder. As an example, the binder may include at least one selected from polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), PVDF-tetrafluoroethylene-propylene terpolymer, PVDF-hexafluoropropylene-tetrafluoroethylene terpolymer, tetrafluoroethylene-hexafluoropropylene copolymer, and fluorinated acrylate resin.

[0081] In some embodiments, the positive electrode active material layer may optionally include a conductive agent. As an example, the conductive agent may include at least one selected from superconducting carbon, acetylene black, carbon black, Ketjen black, carbon dots, carbon nanotubes, graphene, and carbon nanofibers.

[0082] In some embodiments, the positive electrode sheet can be prepared by dispersing the above-mentioned components for preparing the positive electrode sheet, such as positive active material, conductive agent, binder and any other components, in a solvent (e.g., N-methylpyrrolidone) to form a positive electrode slurry; coating the positive electrode slurry onto the positive electrode current collector, and then obtaining the positive electrode sheet after drying, cold pressing and other processes.

[0083] [Negative electrode plate]

[0084] The negative electrode includes a negative current collector and a negative electrode film layer disposed on at least one surface of the negative current collector, the negative electrode film layer comprising a negative electrode active material. In some optional embodiments, the negative electrode can be directly made of a lithium-containing metal sheet. The lithium-containing metal sheet can be lithium metal or an alloy formed of lithium metal with other metals or non-metallic elements.

[0085] As an example, the negative electrode current collector has two surfaces opposite each other in its own thickness direction, and the negative electrode film layer is disposed on either or both of the two opposite surfaces of the negative electrode current collector.

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

[0087] In some embodiments, the negative electrode active material may be a negative electrode active material known in the art for use in batteries. 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, and 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, this application is not limited to these materials, and other conventional 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.

[0088] In some embodiments, the negative electrode film layer may optionally 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).

[0089] In some embodiments, the negative electrode film may optionally include a conductive agent. The conductive agent may be selected from at least one of superconducting carbon, acetylene black, carbon black, Ketjen black, carbon dots, carbon nanotubes, graphene, and carbon nanofibers.

[0090] In some embodiments, the negative electrode film may optionally include other additives, such as thickeners (e.g., sodium carboxymethyl cellulose (CMC-Na)).

[0091] In some embodiments, the negative electrode sheet can be prepared by dispersing the components used to prepare the negative electrode sheet, such as the negative electrode active material, conductive agent, binder and any other components, in a solvent (e.g., deionized water) to form a negative electrode slurry; coating the negative electrode slurry onto the negative electrode current collector, and then obtaining the negative electrode sheet after drying, cold pressing and other processes.

[0092] [Electrolytes]

[0093] The electrolyte acts as a conductor of ions between the positive and negative electrodes. This application does not impose specific restrictions on the type of electrolyte; it can be selected according to requirements. For example, the electrolyte can be liquid, gel, or entirely solid.

[0094] In some embodiments, the electrolyte is an electrolyte solution. The electrolyte solution includes an electrolyte salt and a solvent.

[0095] In some embodiments, the electrolyte salt may 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 difluorooxalate borate, lithium dioxalate borate, lithium difluorodioxalate phosphate, and lithium tetrafluorooxalate phosphate.

[0096] In some embodiments, the solvent may be selected from at least one of ethylene carbonate, propylene carbonate, methyl ethyl carbonate, diethyl carbonate, dimethyl carbonate, dipropyl carbonate, methyl propyl carbonate, ethyl propyl carbonate, butyl carbonate, fluoroethylene carbonate, methyl formate, methyl acetate, ethyl acetate, propyl acetate, methyl propionate, ethyl propionate, propyl propionate, methyl butyrate, ethyl butyrate, 1,4-butyrolactone, sulfolane, dimethyl sulfone, methyl ethyl sulfone, and diethyl sulfone.

[0097] In some embodiments, the electrolyte may optionally include additives. For example, additives may include negative electrode film-forming additives, positive electrode film-forming additives, and may also include additives that can improve certain battery performance, such as additives that improve battery overcharge performance, additives that improve battery high-temperature or low-temperature performance, etc.

[0098] The lithium-ion solid electrolyte can be any of the lithium-ion solid electrolytes commonly used in the art. In some embodiments, the solid electrolyte substrate is a lithium-ion solid electrolyte.

[0099] Examples of lithium-ion solid electrolytes are provided here, including but not limited to:

[0100] LISICON type: such as γ-Li3PO4, etc.;

[0101] NASICON type; for example, Li (1+x1) Q x1 M (2-x1) (PO4)3, 0 ≤ x1 < 1, Q includes at least one of Al, Cr, Ba, Fe, Sc, In, Lu, Y, La;

[0102] Garnet type; for example, Li (7-x2) La3Zr (2-x2) M x2 O12, etc., 0 ≤ x2 < 1, M includes at least one of Sb, Nb, Ta, Te, W;

[0103] LIPON type: for example, Li x3 PO y1 N z1 ; 0 < x3 ≤ 1, 0 < y1 ≤ 1, 0 < z1 ≤ 1;

[0104] Perovskite type: for example, Li x4 Q (2 / 3-x4) MO3, etc., 0.04 < x4 < 0.17, Q includes at least one of La, Sr, Ba, Nd, M includes at least one of Al, Ti, Ge;

[0105] Anti-Perovskite type: for example, Li3OCl, etc.;

[0106] Thio-LiSICON type: for example, Li (3+x5) My2A (1-y2) Q (4-z2) T z2 , where -1 < x5 < 2, 0 ≤ y2 ≤ 1, 0 ≤ z2 ≤ 2, M includes at least one of B, Al, In, Si, Ge, Sn, Ti, W, Mo, A includes at least one of P, As, Sb, Bi, Q includes at least one of S, Se, T includes at least one of F, Cl, Br, I;

[0107] Sulfide solid electrolyte, including: Thiophosphate type: Li3PS4, etc., Argyrodite type: Li6PS5Cl, Halide type: Li3InCl6, Hydride type: 0.7Li(CB9H 10 ) - 0.3Li(CB 11 H 12 ) at least one of; for example, Li (10+x6) M (1+y3) A (2-y3) Q (12-z3) H z3Type: where -2 < x6 < 2, 0 ≤ y3 ≤ 2, 0 ≤ z3 ≤ 2, M includes at least one of B, Al, In, Si, Ge, Sn, Ti, W, Mo; A includes at least one of P, As, Sb, Bi, Q includes at least one of S, Se, H includes at least one of F, Cl, Br, I: (100 - x7)Li2S·x7M·y4Q type: where 20 ≤ x7 ≤ 30, 0 ≤ y4 ≤ 50, M includes at least one of B2S3, Al2S3, In2S3, SiS2, GeS2, SnS2, P2S5, As2S3, Sb2S5, Bi2S3, WS2, MoS2, Q includes at least one of B2O3, Al2O3, In2O3, SiO2, GeO2, SnO2, P2O5, Sb2O5, Bi2O3, WO2, WO3, MoO2, MoO3, Fe2O3, ZnO, MgO, CuO, CaO, LiN, Li2O, LiF, LiCl, LiBr, LiI; Argyrodite type: Li (6+x8) M y5 A (1-y5) Q (5-z5) T (1+z5) , where -1 ≤ x8 ≤ 1, 0 ≤ y5 ≤ 1, -1 < z5 ≤ 1, M includes at least one of B, Al, In, Si, Ge, Sn, Ti, W, Mo, A includes at least one of P, As, Sb, Bi, Q includes at least one of S, Se, T includes at least one of F, Cl, Br, I; Halide type: Li3MJ or Li2Sc 2 / 3 J; M includes at least one of Y, Er, In, Sc, Ga, J includes at least one of F, Cl, Br, I.

[0108] When the above sulfide solid electrolyte is a sulfide - type solid electrolyte, it includes but is not limited to: argyrodite electrolyte; binary sulfide - type solid systems such as Li2S - P2S5, Li2S - SiS2, Li2S - GeS, and Li2S - B2S3, and Li2S - Me - P2S5 ternary systems, where Me is selected from Si, Ge, Sn, or Al, etc.

[0109] Specifically, the above sulfide electrolyte is selected from at least one of Li2S - P2S5, Li2S - SiS2, Li2S - GeS, Li2S - B2S3, and Li2S - Me - P2S5.

[0110] [Separator membrane]

[0111] In some embodiments, the secondary battery further includes a separator membrane. The present application does not particularly limit the type of the separator membrane, and any well - known porous - structure separator membrane with good chemical stability and mechanical stability can be selected.

[0112] In some embodiments, the material of the separator can be selected from at least one of glass fiber, nonwoven fabric, polyethylene, polypropylene, and polyvinylidene fluoride. The separator can be a single-layer film or a multi-layer composite film, without particular limitation. When the separator is a multi-layer composite film, the materials of each layer can be the same or different, without particular limitation.

[0113] In some implementations, the positive electrode, negative electrode, and separator can be fabricated into an electrode assembly using a winding or stacking process.

[0114] In some embodiments, the secondary battery may include an outer packaging. This outer packaging may be used to encapsulate the electrode assembly and electrolyte described above.

[0115] In some embodiments, the outer packaging of the secondary battery can be a hard shell, such as a hard plastic shell, an aluminum shell, or a steel shell. The outer packaging of the secondary battery can also be a soft pack, such as a pouch. The material of the soft pack can be plastic; examples of plastics include polypropylene, polybutylene terephthalate, and polybutylene succinate.

[0116] This application does not impose any particular restrictions on the shape of the secondary battery; it can be cylindrical, square, or any other arbitrary shape.

[0117] In some implementations, the secondary batteries can be assembled into a battery module, and the number of secondary batteries contained in the battery module can be one or more, the specific number of which can be selected by those skilled in the art according to the application and capacity of the battery module.

[0118] In some embodiments, the battery modules described above can also be assembled into a battery pack, and the number of battery modules contained in the battery pack can be one or more, the specific number of which can be selected by those skilled in the art according to the application and capacity of the battery pack.

[0119] In some embodiments, the aforementioned electrical device may also include a battery module or battery pack assembled from the aforementioned secondary batteries. The secondary batteries, battery modules, or battery packs can be used as a power source for the electrical device, or as an energy storage unit for the electrical device. The electrical device may include, but is not limited to, mobile devices (e.g., mobile phones, laptops, etc.), electric vehicles (e.g., 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.

[0120] As the electrical device, a secondary battery, battery module, or battery pack can be selected according to its usage requirements. An example electrical device is a pure electric vehicle, a hybrid electric vehicle, or a plug-in hybrid electric vehicle, etc. To meet the high power and high energy density requirements of the secondary battery for this electrical device, a battery pack or battery module can be used.

[0121] Another example device could be a mobile phone, tablet, or laptop. These devices typically require a slim and lightweight design and can use a rechargeable battery as their power source.

[0122] The present application will be further described in detail below with reference to specific embodiments, which should not be construed as limiting the scope of protection claimed in the present application.

[0123] Example 1

[0124] This embodiment provides a lithium nickel cobalt manganese oxide material, and its specific preparation steps and operating parameters are as follows:

[0125] 400kg Ni 0.5 Co 0.2 Mn 0.3 The (OH)2 precursor was sintered in a rotary kiln at 650°C for 150 min in an air atmosphere with a gas flow rate of 600 L / min.

[0126] After sintering, the material is cooled by chilled water. The average cooling rate is controlled at 30℃ / min by adjusting the mass ratio of chilled water to high-temperature material. The material is cooled to below 40℃ to obtain nickel-cobalt-manganese oxide precursor.

[0127] The nickel cobalt manganese oxide precursor and lithium carbonate were mixed evenly at a lithium ratio of 1.02 and then packed into a mortar to a height of 7 cm. The mixture was then calcined in an air atmosphere in a 50-meter roller kiln at a heating rate of 4 °C / min, a calcination temperature of 900 °C, and a time of 8 h to obtain lithium nickel cobalt manganese oxide material.

[0128] Example 2

[0129] This embodiment provides a lithium nickel cobalt manganese oxide material, and its specific preparation steps and operating parameters are as follows:

[0130] 400kg Ni 0.5 Co 0.2 Mn 0.3 The (OH)2 precursor was sintered in a rotary kiln at 480℃ for 30 minutes in an air atmosphere with a gas flow rate of 600 L / min.

[0131] After sintering, the material is cooled using chilled water. The average cooling rate is controlled at 30°C / min by adjusting the mass ratio of chilled water to high-temperature materials. The material is cooled to below 40°C to obtain the nickel-cobalt-manganese oxide precursor (electron microscopy cross-section image shown). Figure 1 (As shown).

[0132] The nickel cobalt manganese oxide precursor and lithium carbonate were mixed evenly at a lithium ratio of 1.02 and then packed into a mortar to a height of 7 cm. The mixture was then calcined in an air atmosphere in a 50-meter roller kiln at a heating rate of 4℃ / min, a calcination temperature of 900℃, and a time of 8 hours to obtain lithium nickel cobalt manganese oxide material.

[0133] Example 3

[0134] This embodiment provides a lithium nickel cobalt manganese oxide material, and its specific preparation steps and operating parameters are as follows:

[0135] 400kg Ni 0.5 Co 0.2 Mn 0.3 The (OH)2 precursor was sintered in a rotary kiln at 550°C for 60 min in an air atmosphere with a gas flow rate of 600 L / min.

[0136] After sintering, the material is cooled by chilled water. The average cooling rate is controlled at 30℃ / min by adjusting the mass ratio of chilled water to high-temperature material. The material is cooled to below 40℃ to obtain nickel-cobalt-manganese oxide precursor.

[0137] The nickel cobalt manganese oxide precursor and lithium carbonate were mixed evenly at a lithium ratio of 1.02 and then packed into a mortar to a height of 7 cm. The mixture was then calcined in an air atmosphere in a 50-meter roller kiln at a heating rate of 4 °C / min, a calcination temperature of 900 °C, and a time of 8 h to obtain lithium nickel cobalt manganese oxide material.

[0138] Example 4

[0139] This embodiment provides a lithium nickel cobalt manganese oxide material, and its specific preparation steps and operating parameters are as follows:

[0140] 400kg Ni 0.5 Co 0.2 Mn 0.3 The (OH)2 precursor was sintered in a rotary kiln at 600℃ for 50 minutes in an air atmosphere with a gas flow rate of 600 L / min.

[0141] After sintering, the material is cooled using chilled water. The average cooling rate is controlled at 30°C / min by adjusting the mass ratio of chilled water to high-temperature materials. The material is cooled to below 40°C to obtain the nickel-cobalt-manganese oxide precursor (electron microscopy cross-section image shown). Figure 2 (As shown).

[0142] The nickel cobalt manganese oxide precursor and lithium carbonate were mixed evenly at a lithium ratio of 1.02 and then packed into a mortar to a height of 7 cm. The mixture was then calcined in an air atmosphere in a 50-meter roller kiln at a heating rate of 4℃ / min, a calcination temperature of 900℃, and a time of 8 hours to obtain lithium nickel cobalt manganese oxide material.

[0143] Example 5

[0144] This embodiment provides a lithium nickel cobalt manganese oxide material, and its specific preparation steps and operating parameters are as follows:

[0145] 400kg Ni 0.5 Co 0.2 Mn 0.3 The (OH)2 precursor was sintered in a rotary kiln at 600℃ for 50 minutes in an air atmosphere with a gas flow rate of 600 L / min.

[0146] After sintering, the material is cooled by chilled water. The average cooling rate is controlled at 20℃ / min by adjusting the mass ratio of chilled water to high-temperature material. The material is cooled to below 40℃ to obtain nickel-cobalt-manganese oxide precursor.

[0147] The nickel cobalt manganese oxide precursor and lithium carbonate were mixed evenly at a lithium ratio of 1.02 and then packed into a mortar to a height of 7 cm. The mixture was then calcined in an air atmosphere in a 50-meter roller kiln at a heating rate of 4℃ / min, a calcination temperature of 900℃, and a time of 8 hours to obtain lithium nickel cobalt manganese oxide material.

[0148] Example 6

[0149] This embodiment provides a lithium nickel cobalt manganese oxide material, and its specific preparation steps and operating parameters are as follows:

[0150] 400kg Ni 0.5 Co 0.2 Mn 0.3 The (OH)2 precursor was sintered in a rotary kiln at 600℃ for 90 min in an air atmosphere with a gas flow rate of 600 L / min.

[0151] After sintering, the material is cooled by chilled water. The average cooling rate is controlled at 25℃ / min by adjusting the mass ratio of chilled water to high-temperature material. The material is cooled to below 40℃ to obtain nickel cobalt manganese oxide precursor.

[0152] The nickel cobalt manganese oxide precursor and lithium carbonate were mixed evenly at a lithium ratio of 1.04 and then packed into a 5cm high container. The mixture was then calcined in an air atmosphere in a 50m roller kiln at a heating rate of 4℃ / min, a calcination temperature of 940℃, and a time of 7h to obtain lithium nickel cobalt manganese oxide material.

[0153] Example 7

[0154] This embodiment provides a lithium nickel cobalt manganese oxide material, and its specific preparation steps and operating parameters are as follows:

[0155] 400kg Ni 0.5 Co 0.2 Mn 0.3 The (OH)2 precursor was sintered in a rotary kiln at 530℃ for 120 min in an air atmosphere with a gas flow rate of 600 L / min.

[0156] After sintering, the material is cooled by chilled water. The average cooling rate is controlled at 23℃ / min by adjusting the mass ratio of chilled water to high-temperature material. The material is cooled to below 40℃ to obtain nickel-cobalt-manganese oxide precursor.

[0157] The nickel cobalt manganese oxide precursor and lithium carbonate were mixed evenly at a lithium ratio of 1.01 and then packed into a mortar to a height of 8 cm. The mixture was then calcined in an air atmosphere in a 50-meter roller kiln at a heating rate of 4℃ / min, a calcination temperature of 890℃, and a time of 13 h to obtain lithium nickel cobalt manganese oxide material.

[0158] Example 8

[0159] This embodiment provides a lithium nickel cobalt manganese oxide material, and its specific preparation steps and operating parameters are as follows:

[0160] 400kg Ni 0.5 Co 0.2 Mn 0.3 The (OH)2 precursor was sintered in a rotary kiln at 620℃ for 55 minutes in an air atmosphere with a gas flow rate of 600 L / min.

[0161] After sintering, the material is cooled by chilled water. The average cooling rate is controlled at 28℃ / min by adjusting the mass ratio of chilled water to high-temperature material. The material is cooled to below 40℃ to obtain nickel-cobalt-manganese oxide precursor.

[0162] The nickel cobalt manganese oxide precursor and lithium carbonate were mixed evenly at a lithium ratio of 1.05 and then packed into a 6cm high container. The mixture was then calcined in an air atmosphere in a 50m roller kiln at a heating rate of 4℃ / min, a calcination temperature of 920℃, and a time of 9h to obtain lithium nickel cobalt manganese oxide material.

[0163] Example 9

[0164] This embodiment provides a lithium nickel cobalt manganese oxide material, and its specific preparation steps and operating parameters are as follows:

[0165] 400kg Ni 0.7 Co0.15 Mn 0.15 The (OH)2 precursor was sintered in a rotary kiln at 570℃ for 50 min in an air atmosphere with a gas flow rate of 600 L / min.

[0166] After sintering, the material is cooled by chilled water. The average cooling rate is controlled at 30℃ / min by adjusting the mass ratio of chilled water to high-temperature material. The material is cooled to below 40℃ to obtain nickel-cobalt-manganese oxide precursor.

[0167] The nickel cobalt manganese oxide precursor and lithium hydroxide were mixed evenly at a lithium ratio of 1.02 and then packed into a mortar to a height of 7 cm. The mixture was then calcined in an air atmosphere in a 50-meter roller kiln at a heating rate of 4℃ / min, a calcination temperature of 790℃, and a time of 8 hours to obtain lithium nickel cobalt manganese oxide material.

[0168] Example 10

[0169] This embodiment provides a lithium nickel cobalt manganese oxide material, and its specific preparation steps and operating parameters are as follows:

[0170] 400kg Ni 0.6 Co 0.2 Mn 0.2 The (OH)2 precursor was sintered in a rotary kiln at 570℃ for 50 min in an air atmosphere with a gas flow rate of 600 L / min.

[0171] After sintering, the material is cooled by chilled water. The average cooling rate is controlled at 30℃ / min by adjusting the mass ratio of chilled water to high-temperature material. The material is cooled to below 40℃ to obtain nickel-cobalt-manganese oxide precursor.

[0172] The nickel cobalt manganese oxide precursor and lithium oxide were mixed evenly at a lithium ratio of 1.02 and then packed into a mortar to a height of 7 cm. The mixture was then calcined in an air atmosphere in a 50-meter roller kiln at a heating rate of 4℃ / min, a calcination temperature of 810℃, and a time of 8 hours to obtain lithium nickel cobalt manganese oxide material.

[0173] Comparative Example 1

[0174] This comparative example provides a lithium nickel cobalt manganese oxide material, and its specific preparation steps and operating parameters are as follows:

[0175] 400kg Ni 0.5 Co 0.2 Mn 0.3 (OH)2 precursor (electron microscopy cross-section shown) Figure 3The mixture (as shown) was thoroughly mixed with lithium carbonate at a lithium ratio of 1.02 and then packed into a mortar to a height of 7 cm. The mixture was then sintered in an air atmosphere in a 50-meter roller kiln at a heating rate of 4°C / min, a sintering temperature of 900°C, and a time of 8 hours. After sintering, the mixture was cooled to below 40°C in the furnace to obtain lithium nickel cobalt manganese oxide cathode material.

[0176] Comparative Example 2

[0177] This comparative example provides a lithium nickel cobalt manganese oxide material, and its specific preparation steps and operating parameters are as follows:

[0178] 400kg Ni 0.5 Co 0.2 Mn 0.3 The (OH)2 precursor was sintered in a rotary kiln at 650°C for 150 min in an air atmosphere with a gas flow rate of 600 L / min.

[0179] After sintering, the material is cooled by chilled water. The average cooling rate is controlled at 5℃ / min by adjusting the mass ratio of chilled water to high-temperature material. The material is cooled to below 40℃ to obtain nickel-cobalt-manganese oxide precursor.

[0180] The nickel cobalt manganese oxide precursor and lithium carbonate were mixed evenly at a lithium ratio of 1.02 and then packed into a mortar to a height of 7 cm. The mixture was then calcined in an air atmosphere in a 50-meter roller kiln at a heating rate of 4℃ / min, a calcination temperature of 900℃, and a time of 8 hours to obtain lithium nickel cobalt manganese oxide material.

[0181] Comparative Example 3

[0182] This comparative example provides a lithium nickel cobalt manganese oxide material, and its specific preparation steps and operating parameters are as follows:

[0183] 400kg Ni 0.5 Co 0.2 Mn 0.3 The (OH)2 precursor and lithium carbonate were mixed evenly at a lithium ratio of 1.02 and then packed into a mortar to a height of 7 cm. The mixture was then sintered in an air atmosphere in a 50-meter roller kiln at a heating rate of 4℃ / min, a sintering temperature of 950℃, and a time of 15 h to obtain lithium nickel cobalt manganese oxide cathode material.

[0184] Comparative Example 4

[0185] This comparative example provides a lithium nickel cobalt manganese oxide material, and its specific preparation steps and operating parameters are as follows:

[0186] 400kg Ni 0.7 Co 0.15 Mn 0.15The (OH)2 precursor and lithium hydroxide were mixed evenly at a lithium ratio of 1.02 and then packed into a mortar to a height of 7 cm. The mixture was then calcined in an air atmosphere in a 50-meter roller kiln at a heating rate of 4°C / min, a calcination temperature of 790°C, and a time of 8 hours. After calcination, the mixture was cooled to below 40°C in the furnace to obtain lithium nickel cobalt manganese oxide material.

[0187] Comparative Example 5

[0188] This comparative example provides a lithium nickel cobalt manganese oxide material, and its specific preparation steps and operating parameters are as follows:

[0189] 400kg Ni 0.5 Co 0.2 Mn 0.3 The (OH)2 precursor was sintered in a rotary kiln at 600℃ for 50 minutes in an air atmosphere with a gas flow rate of 600 L / min.

[0190] After sintering, the material is cooled using an ice-water mixture. The average cooling rate is controlled at 40°C / min by adjusting the mass ratio of the ice-water mixture to the high-temperature material. Once the temperature is below 40°C, a nickel-cobalt-manganese oxide precursor is obtained (electron microscopy cross-section image shown). Figure 4 (As shown).

[0191] The nickel cobalt manganese oxide precursor and lithium carbonate were mixed evenly at a lithium ratio of 1.02 and then packed into a mortar to a height of 7 cm. The mixture was then calcined in an air atmosphere in a 50-meter roller kiln at a heating rate of 4℃ / min, a calcination temperature of 900℃, and a time of 8 hours to obtain lithium nickel cobalt manganese oxide material.

[0192] Test case

[0193] 1. Test methods for specific surface area and pore volume

[0194] In this application, the specific surface area and pore volume are measured using the static volumetric method, and can be determined using a four-channel fully automatic BET specific surface area analyzer JW-BK400, in accordance with standards GB / T19587-2017 and GB / T 21650.2-2008.

[0195] 2. Test method for residual alkali

[0196] The residual alkali test method in this application refers to standard GB / T 41704-2022. Specifically, 5g ± 0.0005g of positive electrode material is weighed and poured into a 200mL beaker with a magnetic stir bar placed inside. 50mL of distilled water or boiled deionized water is measured using a graduated cylinder and slowly added to the beaker. After the addition is complete, magnetic stirring is performed at 500 rpm for 10 minutes. After stirring, the mixture is filtered into a 100mL volumetric flask, diluted to volume, and shaken to obtain the sample solution. The sample solution is then titrated to obtain two titration jump points. The residual alkali content (LiOH, Li2CO3) is calculated based on the titration volumes at the two points.

[0197] 3. Electrochemical performance testing

[0198] The nickel-cobalt-manganese lithium materials prepared in the embodiments and comparative examples of this application were assembled into coin cells. The specific method is as follows: Lithium-cobalt-manganese oxide material, PVDF, and acetylene black were mixed uniformly at a mass ratio of 8:1:1. Nitrogen-methylpyrrolidone was added and stirred for 3 hours to obtain a uniform slurry. The slurry was uniformly coated onto aluminum foil using a coating machine. After vacuum drying at 110°C for 8 hours, the foil was rolled and cut to obtain a positive electrode sheet with a diameter of 14 mm. The electrode was then transferred to an argon-atmospheric glove box. Using RNCM523 as the working electrode, a lithium metal sheet as the counter electrode, a polyethylene / polypropylene membrane (Celgard 2400) as the separator, and a 1M LiPF6 EC:DMC:DEC solution (volume ratio 1:1:1, with 5wt% FEC added) as the electrolyte, a CR2025 coin cell (solid density 25 mg / cm³) was assembled. 2 The battery was tested for charge / discharge and room temperature DCR on the Neware battery testing system.

[0199] The specific test results are shown in the table below:

[0200] Table 1

[0201]

[0202]

[0203] As can be seen from the data in the table and the attached figures, the cross-sectional view shows that the nickel-cobalt-manganese oxide precursor obtained in the examples has a distinct porous structure, which is more conducive to the lithium intercalation process during the subsequent calcination reaction, resulting in a high-performance lithium nickel-cobalt-manganese oxide cathode material. The low lithium ratio combined with a more favorable lithium intercalation pathway allows more lithium ions to be effectively intercalated into the cathode material, significantly reducing the content of residual alkali (LiOH and Li2CO3) on the product surface. The good lithium ion intercalation and low residual alkali result in a lower discharge rate (DCR) and better discharge and cycle performance. A comparison of Examples 3 and 4 with Examples 1-2 shows that a suitable oxidation temperature and oxidation time can maximize the opening of the pores inside the precursor. Combined with rapid cooling to interrupt the pore closure process, a precursor with a large specific surface area and pore volume can be obtained. A comparison of Examples 4-5 and Comparative Examples 2 and 5 shows that the cooling rate affects the degree of pore closure. At the same sintering temperature and time, rapid cooling can obtain a nickel-cobalt-manganese oxide precursor with a larger specific surface area and pore volume. However, an excessively rapid cooling rate can cause excessive volume expansion and contraction of the precursor, forming through-cracks. Figure 4 This will lead to electrolyte intrusion during use, triggering a series of side reactions and affecting the material's cycle stability. As shown in Example 9 and Comparative Example 4, a precursor with a large specific surface area and pore volume can exhibit higher reactivity in subsequent experiments, which is beneficial for the lithium-ion intercalation process. It can be adapted to lower calcination temperatures, calcination times, and lithium ratios. The low lithium ratio and high lithium-ion intercalation activity result in lithium nickel cobalt manganese oxide materials with low surface residual alkali, low secondary battery internal resistance, and high discharge and cycle performance. This principle also applies to cathode materials with different Ni contents.

[0204] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this application.

Claims

1. A nickel-cobalt-manganese oxide precursor, characterized in that, The specific surface area of ​​the nickel-cobalt-manganese oxide precursor is 50-150 m². 2 / g, pore volume 0.1-0.5cm³ 3 / g.

2. The nickel-cobalt-manganese oxide precursor according to claim 1, characterized in that, The specific surface area of ​​the nickel-cobalt-manganese oxide precursor is 70-150 m². 2 / g, pore volume 0.15-0.45cm³ 3 / g.

3. A method for preparing the nickel-cobalt-manganese oxide precursor according to claim 1 or 2, characterized in that, Includes the following steps: S1, sintering nickel cobalt manganese hydroxide at 480℃~650℃ for 30min~150min; S2, after sintering, is cooled at an average cooling rate of 20-30℃ / min to obtain nickel cobalt manganese oxide precursor.

4. The method for preparing the nickel-cobalt-manganese oxide precursor according to claim 3, characterized in that, In step S1, the sintering temperature is 550℃~650℃, and the sintering time is 40min~60min; And / or, in step S1, the sintering atmosphere is an oxygen-containing atmosphere, or optionally, the sintering atmosphere is an air atmosphere; And / or, in step S2, the average cooling rate is 25–30 °C / min; And / or, in step S2, the temperature is lowered to below 40°C.

5. A method for preparing lithium nickel cobalt manganese oxide material, characterized in that, Includes the following steps: S11, the lithium source is mixed with the nickel cobalt manganese oxide precursor according to any one of claims 1-2 or the nickel cobalt manganese oxide precursor prepared by the preparation method according to any one of claims 3-4 to obtain a mixture; S12, the mixture is calcined to obtain lithium nickel cobalt manganese oxide material.

6. The method for preparing lithium nickel cobalt manganese oxide material according to claim 5, characterized in that, In step S11, the molar ratio of the lithium source to all metal elements in the nickel-cobalt-manganese oxide precursor is 1.01 to 1.05, and optionally 1.01 to 1.

03. And / or, in step S12, the calcination temperature is 790℃~940℃, and the calcination time is 7~13h, optionally 7~9h; And / or, in step S12, the heating rate of the calcination step is 1.5-7℃ / min; And / or, in step S12, calcination is carried out in a roller kiln, with the height of the kiln being 5-8 cm, optionally 7-8 cm; And / or, in step S12, the calcination atmosphere is an oxygen-containing atmosphere, or optionally, the calcination atmosphere is an air atmosphere.

7. A lithium nickel cobalt manganese oxide material, characterized in that, It is prepared by the preparation method described in claim 5 or 6.

8. A positive electrode sheet, characterized in that, include: Positive current collector, and A positive electrode active material layer disposed on at least one side of the positive electrode current collector, the positive electrode active material layer comprising the lithium nickel cobalt manganese oxide material as described in claim 7.

9. A secondary battery, characterized in that, Includes the positive electrode sheet as described in claim 8.

10. An electrical appliance, characterized in that, Includes the secondary battery as described in claim 9.

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