Magnesium-zirconium doped precursor, positive electrode material and preparation method and application of magnesium-zirconium doped precursor and positive electrode material

Abstract

The invention relates to a magnesium-zirconium-doped precursor, a positive electrode material and a preparation method and application of the magnesium-zirconium-doped precursor and the positive electrode material. The chemical components of the magnesium-zirconium doped precursor meet the following formula: Ni (1-x-y) ZryMgz (OH) 2, wherein 0 lt; xlt; 0.015, 0 lt; yt; Yt; and 0.015% of the total weight. When a positive electrode material prepared from the magnesium-zirconium doped precursor is used for preparing a battery, the charge-discharge performance and the cycle stability of the battery can be improved at the same time. And compared with the commonly used doping element cobalt in the traditional technology, the doping elements Mg and Zr in the magnesium-zirconium doped precursor are cheaper, so that the cost can be further reduced.

Description

Technical Field

[0001] The present invention relates to the field of battery technology, and in particular to a magnesium-zirconium doped precursor, a positive electrode material, and a preparation method and application thereof. Background Art

[0002] In recent years, with the continuous development of the new energy industry and the automobile industry, people's demand for electric vehicles, electric bicycles and other electrical devices has increased, and thus the performance requirements for batteries have become higher and higher.

[0003] Lithium batteries are commonly used power batteries. Among them, lithium nickel oxide positive electrode materials have high energy density and are one of the commonly used positive electrode materials for lithium batteries. However, their shortcomings are also particularly obvious. The structural stability and interface stability are poor. Irreversible phase changes are prone to occur during the cycle process, and the layered structure gradually changes to a rock salt structure. The phase change on the surface will extend to the interior of the particles, and the particles will produce intercrystalline cracks and intracrystalline cracks, which will eventually lead to battery failure. In addition, the initial efficiency is low, which limits the improvement of battery performance.

[0004] Therefore, the traditional technology still needs to be improved. Summary of the invention

[0005] Based on this, the present invention provides a magnesium-zirconium doped precursor, a positive electrode material, and a preparation method and application thereof, which can simultaneously improve the battery cycle performance and the first efficiency.

[0006] In one aspect of the present invention, a magnesium-zirconium doped precursor is provided, wherein the chemical composition of the magnesium-zirconium doped precursor satisfies: Ni (1-x-y) Zr y Mg z (OH) 2 ;

[0007] Among them, 0 <x<0.015,0<y<0.015。

[0008] The above-mentioned magnesium-zirconium doped precursor is doped with a specific amount of magnesium and zirconium. When the magnesium-zirconium doped precursor is used to prepare the positive electrode material, on the one hand, the alkali metal ion layer and the transition metal ion layer can be stabilized, the interlayer distance can be increased, and the crystal layered structure can be stabilized, and the phase change reversibility can be enhanced, that is, while maintaining a high energy density, the structural stability of the positive electrode material is improved; on the other hand, the specific amount of magnesium and zirconium doped can improve the conductivity and ion diffusion rate of the positive electrode material, and at the same time, the sphericity and size consistency of the particles of the prepared positive electrode material can be improved, the surface primary particles have high crystallinity, and the internal structure is dense, which can improve the secondary ball crack problem commonly found in traditional high-nickel precursors. In this way, when the magnesium-zirconium doped precursor is used to prepare the positive electrode material for the preparation of the battery, the charge and discharge performance and cycle stability of the battery can be improved at the same time.

[0009] Compared with the doping element cobalt commonly used in traditional technology, the doping elements Mg and Zr in the above-mentioned magnesium-zirconium doping precursor are cheaper, which can further reduce costs.

[0010] On the other hand, the present application provides a method for preparing the above-mentioned magnesium-zirconium doped precursor, comprising the following steps:

[0011] Providing precursor raw materials according to the chemical composition of the magnesium-zirconium doped precursor: nickel salt, zirconium salt and magnesium salt;

[0012] The precursor raw material, the complexing agent and the alkaline aqueous solution are mixed to carry out a complex precipitation reaction, and then an aging treatment is carried out to prepare the magnesium-zirconium doped precursor.

[0013] In some embodiments, based on the volume of the mixture of the precursor material, the complexing agent and the alkaline aqueous solution, the concentration of the complexing agent is 0.5 mol / L to 2 mol / L; and / or

[0014] During the complex precipitation reaction, the pH value of the reaction system is 10-12.

[0015] In some embodiments, the temperature of the complex precipitation reaction is 40°C to 80°C; and / or

[0016] The aging treatment is performed at a temperature of 40°C to 80°C and for a time of 1h to 24h.

[0017] In some embodiments, in the step of mixing the precursor material, the complexing agent and the alkaline aqueous solution, the precursor material is added in the form of an aqueous solution of the precursor material, the aqueous solution of the precursor material comprises a nickel salt solution, a zirconium salt solution and a magnesium salt solution, the concentration of nickel ions in the nickel salt solution is 0.5 mol / L~2.5 mol / L, the concentration of magnesium ions in the magnesium salt solution is 0.01 mol / L~0.1 mol / L, and the concentration of zirconium ions in the zirconium salt solution is 0.01 mol / L~0.1 mol / L; and / or

[0018] In the step of mixing the precursor material, the complexing agent and the alkaline aqueous solution, the complexing agent is added in the form of an aqueous solution of the complexing agent, and the concentration of the aqueous solution of the complexing agent is 0.2 mol / L to 2 mol / L; and / or

[0019] The concentration of the alkaline aqueous solution is 1 mol / L to 5 mol / L.

[0020] In some embodiments, the steps of mixing the precursor material, the complexing agent and the alkaline aqueous solution are as follows:

[0021] The nickel salt solution, the zirconium salt solution, the magnesium salt solution and the alkaline aqueous solution are pumped into the aqueous solution of the complexing agent, the pumping flow rate of the nickel salt solution is 1 mL / min~50 mL / min, the pumping flow rate of the zirconium salt solution is 1 mL / min~10 mL / min, the pumping flow rate of the magnesium salt solution is 1 mL / min~10 mL / min, and the pumping flow rate of the alkaline aqueous solution is 1 mL / min~50 mL / min.

[0022] In some embodiments, the nickel salt is selected from one or more of nickel sulfate, nickel chloride and nickel nitrate; and / or

[0023] The magnesium salt is selected from one or more of magnesium sulfate, magnesium chloride and magnesium nitrate; and / or

[0024] The zirconium salt is selected from one or more of zirconium sulfate, zirconium chloride and zirconium nitrate; and / or

[0025] The complexing agent is selected from one or more of ammonia water and ammonium bicarbonate; and / or

[0026] The alkaline substance in the alkaline aqueous solution is selected from one or more of lithium hydroxide, sodium hydroxide, potassium hydroxide and sodium carbonate.

[0027] In one embodiment of the present application, there is also a positive electrode material, the chemical composition of the positive electrode material satisfies: LiNi (1-x-y) Zr y Mg y (OH) 2 ; Among them, 0 <x<0.015,0<y<0.015。

[0028] In the above-mentioned positive electrode material, a specific amount of magnesium and zirconium are doped. On the one hand, the alkali metal ion layer and the transition metal ion layer can be stabilized, the interlayer distance can be increased, and the crystal layered structure can be stabilized, and the phase change reversibility can be enhanced, that is, while maintaining a high energy density, the structural stability of the positive electrode material is improved; on the other hand, a specific amount of magnesium and zirconium are doped, which can improve the conductivity and ion diffusion rate of the positive electrode material, and at the same time improve the sphericity and size consistency of the particles of the positive electrode material, the surface primary particles have high crystallinity, and the internal structure is dense, which can improve the secondary ball crack problem commonly found in traditional high-nickel precursors. In this way, when the positive electrode material is used to prepare a battery, the charge and discharge performance and cycle stability of the battery can be improved at the same time, and a good energy density can be maintained.

[0029] Another aspect of the present invention provides a method for preparing the above-mentioned positive electrode material, comprising the following steps:

[0030] Providing a raw material for preparation, wherein the raw material for preparation comprises: at least one of the above-mentioned magnesium-zirconium doped precursor or the magnesium-zirconium doped precursor prepared by the above-mentioned method for preparing the magnesium-zirconium doped precursor, and a lithium source;

[0031] The raw materials are mixed and calcined to prepare the positive electrode material.

[0032] In some embodiments, the calcination temperature is 600°C to 800°C, and the time is 10h to 20h; and / or

[0033] The lithium source is selected from one or more of lithium hydroxide, lithium carbonate and lithium citrate; and / or

[0034] The molar ratio of the magnesium-zirconium doped precursor to the lithium element in the lithium source is 1:1.05-1.10.

[0035] In another aspect of the present invention, a positive electrode sheet is provided, wherein the positive electrode sheet comprises the positive electrode material mentioned above or the positive electrode material prepared by the method for preparing the positive electrode material mentioned above.

[0036] Another aspect of the present invention provides a battery, wherein the battery comprises the above-mentioned positive electrode material or the positive electrode material prepared by the above-mentioned method for preparing the positive electrode material or the above-mentioned positive electrode sheet.

[0037] According to another aspect of the present invention, there is provided an electrical device, characterized in that the electrical device comprises the battery as described above. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] 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. Moreover, the same reference numerals are used throughout the drawings to represent the same components. In the drawings:

[0039] Figure 1 This is a scanning electron microscope image of the surface of the magnesium-zirconium doped precursor in Example 1 of the present application;

[0040] Figure 2 This is the EDS-mapping diagram of the magnesium-zirconium doped precursor in Example 1 of the present application;

[0041] Figure 3 This is a scanning electron microscope image of a cross section of a magnesium-zirconium doped precursor in Example 1 of the present application;

[0042] Figure 4 is an XRD diagram of a cross section of a magnesium-zirconium doped precursor in Example 1 of the present application;

[0043] Figure 5This is a scanning electron microscope image of the surface of the positive electrode material in Example 1 of the present application;

[0044] Figure 6 This is an EDS-mapping image of the surface of the positive electrode material in Example 1 of the present application;

[0045] Figure 7 The transmission electron microscope image and EDS-mapping image of the positive electrode material in Example 1 of the present application;

[0046] Figure 8 The first charge and discharge performance curves of the batteries in Comparative Example 1 and Example 1 of the present application;

[0047] Fig. 9 It is a cycle performance curve diagram of the battery in comparative example 1 and example 1 of the present application. DETAILED DESCRIPTION

[0048] In order to facilitate the understanding of the present invention, the present invention will be described more comprehensively below. Preferred embodiments of the present invention are provided in the specific embodiments. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the understanding of the disclosure of the present invention more thorough and comprehensive.

[0049] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which the present invention belongs. The terms used herein in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The term "and / or" used herein includes any and all combinations of one or more of the related listed items.

[0050] the term

[0051] Unless otherwise specified or incompatible herewith, the terms and phrases used herein shall have the following meanings:

[0052] The terms "and / or", "or / and", and "and / or" used in this article have a selection range that includes any one of two or more related listed items, and also includes any and all combinations of related listed items, and the arbitrary and all combinations include any combination of two related listed items, any more related listed items, or all related listed items. It should be noted that when at least three items are connected by at least two conjunctions selected from "and / or", "or / and", and "and / or", it should be understood that in this application, the technical solution undoubtedly includes technical solutions that are all connected by "logical and", and undoubtedly includes technical solutions that are all connected by "logical or". For example, "A and / or B" includes three parallel solutions of A, B and the combination of A and B. For example, the technical solution of "A, and / or, B, and / or, C, and / or, D" includes any one of A, B, C, and D (that is, the technical solution that is all connected by "logical OR"), and also includes any and all combinations of A, B, C, and D, that is, the combination of any two or any three of A, B, C, and D, and also includes the combination of four of A, B, C, and D (that is, the technical solution that is all connected by "logical AND").

[0053] In the present invention, "plurality", "multiple", "multiple times", etc., unless otherwise specified, refer to a number greater than 2 or equal to 2. For example, "one or more" means one or greater than or equal to two.

[0054] In the present invention, in the "first aspect", "second aspect", "third aspect", "fourth aspect", etc., the terms "first", "second", "third", "fourth", etc. are used only for descriptive purposes and cannot be understood as indicating or implying relative importance or quantity, nor can they be understood as implicitly indicating the importance or quantity of the indicated technical features. Moreover, "first", "second", "third", "fourth", etc. only serve the purpose of non-exhaustive enumeration and description, and it should be understood that they do not constitute a closed limitation on quantity.

[0055] In the present invention, the technical features described in an open manner include closed technical solutions composed of the listed features, and also include open technical solutions containing the listed features.

[0056] In the present invention, when it comes to a numerical interval (i.e., a numerical range), unless otherwise specified, the distribution of the optional numerical values ​​in the numerical interval is considered to be continuous, and includes the two numerical endpoints (i.e., the minimum value and the maximum value) of the numerical interval, and each numerical value between the two numerical endpoints. Unless otherwise specified, when the numerical interval only refers to the integers in the numerical interval, it includes the two endpoint integers of the numerical range, and each integer between the two endpoints, which is equivalent to directly listing each integer. When multiple numerical ranges are provided to describe features or characteristics, these numerical ranges can be merged. In other words, unless otherwise specified, the numerical range disclosed herein should be understood to include any and all sub-ranges included therein. The "numerical value" in the numerical interval can be any quantitative value, such as a number, a percentage, a ratio, etc. "Numerical interval" allows broadly including numerical interval types such as percentage intervals, ratio intervals, and ratio intervals.

[0057] The temperature parameters in the present invention, if not specifically limited, are allowed to be either constant temperature treatment or to vary within a certain temperature range. It should be understood that the constant temperature treatment allows the temperature to fluctuate within the precision range controlled by the instrument. Fluctuations within the range of ±5°C, ±4°C, ±3°C, ±2°C, and ±1°C are allowed.

[0058] In the present application, "room temperature" or "normal temperature" refers to 10°C ~ 35°C, and further, may refer to 20°C ~ 30°C.

[0059] The mass or weight of the relevant components mentioned in the description of the embodiments of the present invention may not only refer to the specific content of each component, but also indicate the proportional relationship of the mass or weight between the components. Therefore, as long as the content of the relevant components is proportionally enlarged or reduced according to the description of the embodiments of the present invention, it is within the scope disclosed in the description of the embodiments of the present invention. Specifically, the mass or weight described in the description of the embodiments of the present invention may be units known in the chemical industry such as μg, mg, g, and kg.

[0060] One embodiment of the present invention provides a magnesium-zirconium doped precursor, the chemical composition of which satisfies: Ni (1-x-y) Zr y Mg z (OH) 2 .

[0061] Among them, 0 <x<0.015,0<y<0.015。

[0062] In the above magnesium-zirconium doped precursor, a specific amount of magnesium and zirconium is doped. When preparing the cathode material using this magnesium-zirconium doped precursor, on the one hand, it can stabilize the alkali metal ion layer and the transition metal ion layer, increase the layer spacing, and stabilize the crystal layer structure, enhancing the reversibility of phase change. That is, while maintaining a high energy density, the structural stability of the cathode material is improved. On the other hand, doping a specific amount of magnesium and zirconium can improve the conductivity and ion diffusion rate of the cathode material. At the same time, it can improve the particle sphericity and size consistency of the prepared cathode material. The surface primary particles have high crystallinity and the internal structure is dense, which can improve the problem of secondary spherical cracks commonly existing in traditional high-nickel precursors. Thus, when using this magnesium-zirconium doped precursor to prepare the cathode material for manufacturing a battery, it can simultaneously improve the charge-discharge performance and cycle stability of the battery and maintain good energy density.

[0063] Moreover, compared with the commonly used doping element cobalt in traditional technologies, the doping elements Mg and Zr in the above magnesium-zirconium doped precursor are cheaper and can further reduce costs.

[0064] For the above "0 < x < 0.015", the values include the minimum and maximum values of this range, as well as each value between such minimum and maximum values. Specific examples include but are not limited to the point values in the embodiments and the following point values: 0.015, 0.014, 0.013, 0.012, 0.011, 0.01, 0.009, 0.008, 0.007, 0.006, 0.005, 0.004, 0.003, 0.002, 0.001; or a range composed of any two numerical values.

[0065] For the above "0 < y < 0.015", the values include the minimum and maximum values of this range, as well as each value between such minimum and maximum values. Specific examples include but are not limited to the point values in the embodiments and the following point values: 0.015, 0.014, 0.013, 0.012, 0.011, 0.01, 0.009, 0.008, 0.007, 0.006, 0.005, 0.004, 0.003, 0.002, 0.001; or a range composed of any two numerical values.

[0066] On the other hand, the present invention provides a method for preparing the above magnesium-zirconium doped precursor, including the following steps S10 to S20.

[0067] Step S10: Provide precursor raw materials according to the chemical components of the magnesium-zirconium doped precursor: nickel salt, zirconium salt, and magnesium salt.

[0068] Step S20: Mix the precursor raw materials, complexing agent, and alkaline aqueous solution for complex precipitation reaction, and then perform aging treatment to prepare the magnesium-zirconium doped precursor.

[0069] In some of the embodiments, the concentration of the complexing agent is 0.5 mol / L to 2 mol / L based on the volume of the mixture of the precursor, the complexing agent and the alkaline aqueous solution.

[0070] In some embodiments, the complexing agent is selected from one or more of ammonia water and ammonium bicarbonate.

[0071] In some of the embodiments, during the complex precipitation reaction, the pH value of the reaction system is 10-12.

[0072] In some embodiments, the alkaline substance in the alkaline aqueous solution is selected from one or more of lithium hydroxide, sodium hydroxide, potassium hydroxide, and sodium carbonate.

[0073] In some embodiments, the concentration of the alkaline aqueous solution is 1 mol / L to 5 mol / L.

[0074] It can be understood that the amount of alkaline aqueous solution added is based on maintaining the pH value of the reaction system at 10-12.

[0075] In some embodiments, the temperature of the complex precipitation reaction is 40° C. to 80° C. Further, the reaction time is 40 h to 55 h.

[0076] In some of the embodiments, the temperature of the complex precipitation reaction is 60° C., the time is 48 h, and the reaction is stopped when the particle size D50 of the precipitated product reaches about 6 μm.

[0077] In some of the embodiments, the complex precipitation reaction is carried out under stirring conditions; further, the stirring speed is 600 rpm ~1200 rpm.

[0078] In some embodiments, the aging treatment temperature is 40° C. to 80° C., and the time is 1 h to 24 h.

[0079] In some embodiments, the aging treatment temperature is 60° C. and the time is 8 h.

[0080] In some of the embodiments, in the step of mixing the precursor raw material, the complexing agent and the alkaline aqueous solution, the precursor raw material is added in the form of an aqueous solution of the precursor raw material, the aqueous solution of the precursor raw material includes a nickel salt solution, a zirconium salt solution and a magnesium salt solution, the concentration of nickel ions in the nickel salt solution is 0.5mol / L~2.5mol / L, the concentration of magnesium ions in the magnesium salt solution is 0.01mol / L~0.1mol / L, and the concentration of zirconium ions in the zirconium salt solution is 0.01mol / L~0.1mol / L.

[0081] In some of the embodiments, the concentration of nickel ions in the nickel salt solution is 2 mol / L, the concentration of magnesium ions in the magnesium salt solution is 0.021 mol / L, and the concentration of zirconium ions in the zirconium salt solution is 0.021 mol / L.

[0082] In some of the embodiments, in the step of mixing the precursor material, the complexing agent and the alkaline aqueous solution, the complexing agent is added in the form of an aqueous solution of the complexing agent, and the concentration of the aqueous solution of the complexing agent is 0.2 mol / L to 2 mol / L.

[0083] In some embodiments, the concentration of the aqueous solution of the complexing agent is 1 mol / L.

[0084] In some embodiments, the steps of mixing the precursor material, the complexing agent and the alkaline aqueous solution are as follows:

[0085] Pump nickel salt solution, zirconium salt solution, magnesium salt solution and alkaline aqueous solution into the aqueous solution of the complexing agent. The pumping flow rate of the nickel salt solution is 1 mL / min~50 mL / min, the pumping flow rate of the zirconium salt solution is 1 mL / min~10 mL / min, the pumping flow rate of the magnesium salt solution is 1 mL / min~10 mL / min, and the pumping flow rate of the alkaline aqueous solution is 1 mL / min~50 mL / min.

[0086] In some of the embodiments, the pumping flow rate of the nickel salt solution is 5 mL / min~20 mL / min, the pumping flow rate of the zirconium salt solution is 1 mL / min~5 mL / min, the pumping flow rate of the magnesium salt solution is 1 mL / min~5 mL / min, and the pumping flow rate of the alkaline aqueous solution is 10 mL / min~30 mL / min.

[0087] In some of the embodiments, before the step of pumping the nickel salt solution, zirconium salt solution, magnesium salt solution and alkaline aqueous solution into the aqueous solution of the complexing agent, the step of pumping the aqueous solution of the complexing agent into the reactor is also included; further, the pumping flow rate of the aqueous solution of the complexing agent is 1 mL / min~20 mL / min, and can be optionally 5 mL / min~15 mL / min.

[0088] In some embodiments, the nickel salt is selected from one or more of nickel sulfate, nickel chloride and nickel nitrate; optionally, the nickel salt is selected from nickel sulfate.

[0089] In some embodiments, the magnesium salt is selected from one or more of magnesium sulfate, magnesium chloride, and magnesium nitrate; optionally, the magnesium salt is selected from magnesium sulfate.

[0090] In some of the embodiments, the zirconium salt is selected from one or more of zirconium sulfate, zirconium chloride, and zirconium nitrate; optionally, the zirconium salt is selected from zirconium sulfate.

[0091] In some embodiments, after the step of forming treatment, the following steps are also included:

[0092] The aged product was washed with water, filtered and dried.

[0093] Another embodiment of the present application provides a positive electrode material, the chemical composition of the positive electrode material satisfies: LiNi (1-x-y) Zr y Mg y (OH) 2 ; Among them, 0 <x<0.015,0<y<0.015。

[0094] In the above-mentioned positive electrode material, a specific amount of magnesium and zirconium are doped. On the one hand, the alkali metal ion layer and the transition metal ion layer can be stabilized, the interlayer distance can be increased, and the crystal layered structure can be stabilized, and the phase change reversibility can be enhanced, that is, while maintaining a high energy density, the structural stability of the positive electrode material is improved; on the other hand, a specific amount of magnesium and zirconium are doped, which can improve the conductivity and ion diffusion rate of the positive electrode material, and at the same time improve the sphericity and size consistency of the particles of the positive electrode material, the surface primary particles have high crystallinity, and the internal structure is dense, which can improve the secondary ball crack problem commonly found in traditional high-nickel precursors. In this way, when the positive electrode material is used to prepare a battery, the charge and discharge performance and cycle stability of the battery can be improved at the same time, and a good energy density can be maintained.

[0095] The values ​​of x and y are the same as above and will not be repeated here.

[0096] Another embodiment of the present application provides a method for preparing the above-mentioned positive electrode material, comprising the following steps S30 to S40.

[0097] Step S30: providing raw materials for preparation, the raw materials for preparation comprising: at least one of the above-mentioned magnesium-zirconium doped precursor or the magnesium-zirconium doped precursor prepared by the above-mentioned method for preparing the magnesium-zirconium doped precursor, and a lithium source.

[0098] Step S40: Mixing and calcining the prepared raw materials to prepare the positive electrode material.

[0099] In some of the embodiments, the calcination temperature is 600° C. to 800° C., and the calcination time is 10 h to 20 h.

[0100] In some embodiments, the lithium source is selected from one or more of lithium hydroxide, lithium carbonate and lithium citrate.

[0101] In some of the embodiments, the molar ratio of the magnesium-zirconium doped precursor to the lithium element in the lithium source is 1:1.05-1.10.

[0102] Another embodiment of the present invention further provides a positive electrode sheet, which includes the positive electrode material mentioned above or the positive electrode material prepared by the method for preparing the positive electrode material mentioned above.

[0103] In some of the embodiments, the positive electrode sheet includes a current collector and a positive electrode active layer disposed on at least one surface of the current collector, and the positive electrode active layer includes the above-mentioned positive electrode material.

[0104] In some embodiments, the positive electrode active layer further includes a binder and a conductive agent.

[0105] The conductive agent can be a conductive material commonly used in the art, including but not limited to at least one of graphite, carbon nanotubes, nanofibers, carbon black and graphene. Specifically, it can be selected from at least one of SP, KS-6, acetylene black, branched Ketjen black ECP, SFG-6, vapor-grown carbon fiber VGCF, carbon nanotubes CNTs and graphene and composite conductive agents thereof.

[0106] In some of the embodiments, in the positive electrode active layer, the binder accounts for 0.1% to 20% by mass.

[0107] In some of the embodiments, in the positive electrode active layer, the mass proportion of the positive electrode material is 60% to 99.8%.

[0108] In some of the embodiments, in the positive electrode active layer, the mass proportion of the conductive agent is 0.1% to 20%.

[0109] It is understood that the adhesive may be any type of adhesive commonly used in the art, including but not limited to acrylic adhesive, polytetrafluoroethylene adhesive, and the like.

[0110] Another embodiment of the present application further provides a battery, the positive electrode material of the battery or the positive electrode material prepared by the preparation method of the positive electrode material as described above or the positive electrode sheet as described above.

[0111] In some embodiments, the battery further includes a negative electrode sheet, a separator and an electrolyte.

[0112] The negative electrode sheet, separator and electrolyte mentioned above may adopt the negative electrode sheet, separator and electrolyte of various secondary batteries at normal pressure in the art, and will not be described in detail here.

[0113] Another embodiment of the present application further provides an electrical device, which also includes the above-mentioned battery.

[0114] In some embodiments, the electrical device includes a vehicle, including but not limited to an electric vehicle, a hybrid electric vehicle, or a plug-in hybrid electric vehicle.

[0115] The present invention will be described below in conjunction with specific embodiments, but the present invention is not limited to the following embodiments. It should be understood that the attached claims summarize the scope of the present invention. Under the guidance of the concept of the present invention, those skilled in the art should realize that certain changes made to the various embodiments of the present invention will be covered by the spirit and scope of the claims of the present invention.

[0116] Example 1

[0117] (1) Preparation of magnesium zirconium doped precursor, as follows:

[0118] Deionized water was used to prepare an ammonia solution A with a concentration of 1 mol / L; deionized water was used to prepare an alkaline solution B with a sodium hydroxide solution concentration of 4 mol / L; deionized water was used to prepare nickel sulfate solution C, magnesium sulfate solution D and zirconium sulfate solution E with nickel sulfate, magnesium sulfate and zirconium sulfate, respectively. The concentration of nickel sulfate solution C was 2 mol / L, and the concentrations of magnesium sulfate solution D and zirconium sulfate solution E were both 0.021 mol / L. Among them, the molar ratio of Ni in nickel sulfate solution C, Mg in magnesium sulfate solution D and Zr in zirconium sulfate conforms to Ni 0.98 Zr 0.01 Mg 0.01 (OH) 2 The stoichiometric ratio in .

[0119] 500 ml of deionized water was added to a 10 L reactor, and ammonia solution A was added to adjust the pH to 10.5, and the temperature was controlled at 60°C and the stirring speed was 800 rpm. Then, nickel sulfate solution C, magnesium sulfate solution D and zirconium sulfate solution E were introduced into the reactor through a precision constant flow pump for complex precipitation reaction, and the pH of the reaction process was controlled to 11.0 by pumping in alkaline aqueous solution B. At the same time, the temperature was controlled at 60°C to maintain the reaction for 48 hours. When the particle size D50 of the material in the reactor reached about 6 μm, the feeding was stopped, and the material was discharged after stirring and aging for 8 hours, washed and filtered with deionized water, dried at 120°C in a blast drying oven for 12 hours, and ground and sieved to obtain magnesium zirconium doped precursor Ni 0.98 Zr 0.01 Mg 0.01 (OH) 2 .

[0120] (2) Test characterization of magnesium-zirconium doped precursor:

[0121] 1: The surface of the magnesium-zirconium doped precursor obtained in Example 1 was analyzed using a scanning electron microscope to obtain a surface scanning electron microscope image. The scanning electron microscope images under different magnifications are shown in FIG. Figure 1 Then, X-ray energy spectrum element analysis (EDS-mapping) is performed, and the EDS-mapping diagram is as follows Figure 2As shown, from left to right are the analysis diagrams of nickel (Ni), zirconium (Zr) and magnesium (Mg); the magnesium-zirconium doped precursor is further cut open, and the cross-section of the magnesium-zirconium doped precursor is analyzed using a scanning electron microscope to obtain a scanning electron microscope image of the cross-section, as shown in FIG. Figure 3 shown.

[0122] 2: The magnesium-zirconium doped precursor obtained in Example 1 was subjected to an X-ray diffraction (XRD) test. The X-ray diffraction (XRD) comparison diagram is shown in FIG. Figure 4 As shown, the horizontal axis represents the angle (2θ) and the vertical axis represents the diffraction intensity (Intansity).

[0123] (3) Preparation of positive electrode materials, as follows:

[0124] The magnesium zirconium doped precursor and lithium hydroxide were ground and mixed at a molar ratio of 1:1.05; they were pre-sintered at 500°C for 5 hours and then calcined at 700°C for 12 hours to obtain the positive electrode material LiNi 0.98 Zr 0.01 Mg 0.01 (OH) 2 .

[0125] (4) Characterization test of positive electrode materials. The specific steps are as follows:

[0126] 1: Use a scanning electron microscope to analyze the surface of the positive electrode material and obtain its surface scanning electron microscope image. The scanning electron microscope images under different magnifications are as follows: Figure 5 Then, X-ray energy spectrum element analysis (EDS-mapping) is performed, and the EDS-mapping diagram is as follows Figure 6 As shown; the positive electrode material is further analyzed by transmission electron microscopy, and X-ray energy spectrum elemental image analysis (EDS-mapping) is performed at the same time. The transmission electron microscopy image is as shown Figure 7 As shown in (a), (b) to (d) are the EDS-mapping images of nickel (Ni), zirconium (Zr) and magnesium (Mg) respectively.

[0127] (5) Preparation of batteries and their performance testing, as follows:

[0128] Referring to the CR2032 button cell, the positive electrode sheet was prepared using the above positive electrode material and assembled into a button cell: in the positive electrode sheet, the mass ratio of positive electrode material: Super-P: PVDF = 80:10:10, Celgard 2500 separator was used, the negative electrode used metal lithium sheet, and the electrolyte was LiPF 6 Mix the solution. Perform the following test:

[0129] 1: Place the button battery under 25℃, 0.1 C conditions for charge and discharge, and obtain the first charge and discharge curve under 25℃, 1 C conditions, such as Figure 8 The specific data are shown in Table 1.

[0130] 2: Place the button cell at 25°C and 0.1 C for cycle performance test (1 C = 180 mAh g -1 ), the cycle performance curve is as follows Fig. 9 The specific results are shown in Table 1.

[0131] Example 2

[0132] Example 2 is basically the same as Example 1, except that step (3) is as follows:

[0133] The magnesium-zirconium doped precursor and lithium hydroxide were ground and mixed at a molar ratio of 1:1.05; they were pre-calcined at 450°C for 5 hours and then calcined at 650°C for 12 hours to obtain a positive electrode material.

[0134] The other steps are the same as those in Example 1.

[0135] Example 3

[0136] Example 3 is basically the same as Example 1, except that step (3) is as follows:

[0137] The magnesium-zirconium doped precursor and lithium hydroxide were ground and mixed at a molar ratio of 1:1.1; the mixture was directly calcined at 700° C. for 12 hours to obtain a positive electrode material.

[0138] The other steps are the same as those in Example 1.

[0139] Comparative Example 1

[0140] Comparative Example 1 is substantially the same as Example 1, except that step (1) in Comparative Example 1 is as follows:

[0141] Deionized water was used to prepare an ammonia solution A with a concentration of 1 mol / L; deionized water was used to prepare an alkaline aqueous solution B with a sodium hydroxide solution concentration of 4 mol / L; deionized water and nickel sulfate were used to prepare a nickel sulfate solution C with a concentration of 2 mol / L.

[0142] Solutions A, B, and C were introduced into the reactor through a precision constant flow pump, and the pH of the reaction process was controlled to be 10.7 and the temperature to be 60 °C. The reaction was maintained for 48 h. When the particle size D50 of the material in the reactor reached about 6.0 μm, the feeding was stopped, and the material was discharged after continued stirring and aging for 8 h. The product was washed with deionized water, filtered, and dried in a forced air drying oven at 120 °C for 12 h to obtain a precursor.

[0143] The other steps are the same as those in Example 1. Please see Table 1 for specific test results.

[0144] The battery performances of Example 1 and Comparative Example 1 are shown in Table 1.

[0145] Table 1

[0146]

[0147] It can be seen from the data in Table 1 that when the magnesium-zirconium doped precursor is used to prepare the positive electrode material for preparing the battery, the charge and discharge performance and cycle stability of the battery can be improved at the same time.

[0148] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0149] The above-mentioned embodiments only express several implementation methods of the present invention, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. A magnesium-zirconium doped precursor, It is characterized in that The chemical composition of the magnesium-zirconium doped precursor satisfies: Ni (1-x-y) Zr y Mg z (OH) 2 ; Among them, 0 <x<0.015,0<y<0.015。 2. The method for preparing a magnesium-zirconium doped precursor according to claim 1, It is characterized in that The steps include: Providing precursor raw materials according to the chemical composition of the magnesium-zirconium doped precursor: nickel salt, zirconium salt and magnesium salt; The precursor raw material, the complexing agent and the alkaline aqueous solution are mixed to carry out a complex precipitation reaction, and then an aging treatment is carried out to prepare the magnesium-zirconium doped precursor.

3. The method for preparing a magnesium-zirconium doped precursor according to claim 2, It is characterized in that Based on the volume of the mixed solution of the precursor material, the complexing agent and the alkaline aqueous solution, the concentration of the complexing agent is 0.5 mol / L to 2 mol / L; and / or During the complex precipitation reaction, the pH value of the reaction system is 10-12.

4. The method for preparing a magnesium-zirconium doped precursor according to any one of claims 2 to 3, It is characterized in that The temperature of the complex precipitation reaction is 40°C to 80°C; and / or The aging treatment is performed at a temperature of 40°C to 80°C and for a time of 1h to 24h.

5. The method for preparing a magnesium-zirconium doped precursor according to any one of claims 2 to 3, It is characterized in that In the step of mixing the precursor material, the complexing agent and the alkaline aqueous solution, the precursor material is added in the form of an aqueous solution of the precursor material, the aqueous solution of the precursor material comprises a nickel salt solution, a zirconium salt solution and a magnesium salt solution, the concentration of nickel ions in the nickel salt solution is 0.5 mol / L to 2.5 mol / L, the concentration of magnesium ions in the magnesium salt solution is 0.01 mol / L to 0.1 mol / L, and the concentration of zirconium ions in the zirconium salt solution is 0.01 mol / L to 0.1 mol / L; and / or In the step of mixing the precursor material, the complexing agent and the alkaline aqueous solution, the complexing agent is added in the form of an aqueous solution of the complexing agent, and the concentration of the aqueous solution of the complexing agent is 0.2 mol / L to 2 mol / L; and / or The concentration of the alkaline aqueous solution is 1 mol / L to 5 mol / L.

6. The method for preparing a magnesium-zirconium doped precursor according to claim 5, It is characterized in that The steps of mixing the precursor material, the complexing agent and the alkaline aqueous solution are as follows: The nickel salt solution, the zirconium salt solution, the magnesium salt solution and the alkaline aqueous solution are pumped into the aqueous solution of the complexing agent, the pumping flow rate of the nickel salt solution is 1 mL / min~50 mL / min, the pumping flow rate of the zirconium salt solution is 1 mL / min~10 mL / min, the pumping flow rate of the magnesium salt solution is 1 mL / min~10 mL / min, and the pumping flow rate of the alkaline aqueous solution is 1 mL / min~50 mL / min.

7. The method for preparing a magnesium-zirconium doped precursor according to any one of claims 2 to 3, It is characterized in that The nickel salt is selected from one or more of nickel sulfate, nickel chloride and nickel nitrate; and / or The magnesium salt is selected from one or more of magnesium sulfate, magnesium chloride and magnesium nitrate; and / or The zirconium salt is selected from one or more of zirconium sulfate, zirconium chloride and zirconium nitrate; and / or The complexing agent is selected from one or more of ammonia water and ammonium bicarbonate; and / or The alkaline substance in the alkaline aqueous solution is selected from one or more of lithium hydroxide, sodium hydroxide, potassium hydroxide and sodium carbonate.

8. A positive electrode material, It is characterized in that The chemical composition of the positive electrode material satisfies: LiNi (1-x-y) Zr y Mg y (OH) 2 ; Among them, 0 <x<0.015,0<y<0.015。 9. The method for preparing the positive electrode material according to claim 8, It is characterized in that The steps include: Providing a raw material for preparation, wherein the raw material for preparation comprises: at least one of the magnesium-zirconium doped precursor according to claim 1 or the magnesium-zirconium doped precursor prepared by the method for preparing the magnesium-zirconium doped precursor according to any one of claims 2 to 7, and a lithium source; The raw materials are mixed and calcined to prepare the positive electrode material.

10. The method for preparing the positive electrode material according to claim 9, It is characterized in that The calcination treatment temperature is 600°C to 800°C and the time is 10h to 20h; and / or The lithium source is selected from one or more of lithium hydroxide, lithium carbonate and lithium citrate; The molar ratio of the magnesium-zirconium doped precursor to the lithium element in the lithium source is 1:1.05-1.

10.

11. A positive electrode sheet, It is characterized in that The positive electrode sheet comprises the positive electrode material according to claim 8 or the positive electrode material prepared by the method for preparing the positive electrode material according to any one of claims 9 to 10.

12. A battery, It is characterized in that The battery comprises the positive electrode material as claimed in claim 8 or the positive electrode material prepared by the method for preparing the positive electrode material as claimed in any one of claims 9 to 10 or the positive electrode sheet as claimed in claim 11.

13. An electrical device, It is characterized in that The electric device comprises the battery as claimed in claim 12.

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