High-nickel positive electrode material, and preparation method therefor and use thereof

Abstract

The present application relates to the technical field of lithium-ion batteries, and specifically relates to a high-nickel positive electrode material and a preparation method therefor, a positive electrode sheet, a lithium-ion battery and an electric device. The high-nickel positive electrode material has a general formula of LimNixCoyMnzQiAjEkO2, wherein 0.98≤m≤1.05, 0.74≤x≤0.98, 0≤y≤0.2, 0≤z≤0.2, 0.001≤i≤0.2, 0.002≤j≤0.09, 0.001≤k≤0.06, and x+y+z+i+j+k＝1; Q comprises at least one of Zr, B and Al; A comprises at least one of F, Ca, La and Ru; and E comprises at least one of Na, Ag and Mg. The high-nickel positive electrode material has low direct current resistance (DCR) during cycling.

Description

High nickel cathode material and its preparation method and application

[0001] This application claims priority to the Chinese patent application filed with the China Patent Office on November 23, 2023, with application number 202311574096.8 and application name “High Nickel Positive Electrode Materials, Preparation Methods and Applications Thereof”, the entire contents of which are incorporated by reference into this application. Technical Field

[0002] The present application relates to the technical field of lithium-ion batteries, and in particular to a high-nickel positive electrode material and a preparation method and application thereof. Background Art

[0003] Lithium-ion batteries, with their outstanding advantages such as high energy density, excellent cycle life, high operating voltage, low self-discharge rate, and environmental friendliness, have become an ideal power source for electric vehicles, mobile devices, and energy storage. The capacity of the cathode material plays a significant role in lithium-ion batteries. Among them, high-nickel ternary cathode materials offer promising application prospects for lithium-ion batteries due to their low cost, environmental friendliness, high reversible capacity, and abundant raw material resources.

[0004] The capacity retention rate of high nickel ternary cathode material is closely related to its cycle DCR (direct current internal resistance). During the charge and discharge process, high nickel ternary cathode material + The valence state of the transition metal will also change accordingly. 2+ With Li + Close ionic radius, so it is easy to enter Li + This not only leads to Li + The reduction of storage locations reduces the charge and discharge efficiency and will + It becomes an obstacle in the transmission path, thereby reducing the ionic conductivity of the high-nickel ternary positive electrode material, and ultimately leading to an increase in the cyclic DCR of the high-nickel ternary positive electrode material.

[0005] The current common solution is to regulate the ionic conductivity and electronic conductivity of high-nickel ternary positive electrode materials through doping, coating, or a combination of doping and coating. However, the existing doping and coating methods rely solely on external elements to improve conductivity, and do not solve the problem of increased cycle DCR caused by lithium-nickel mixing. There is still a risk of reduced cycle capacity and reduced product safety.

[0006] In view of this, this application is hereby filed. Summary of the Invention

[0007] The first object of the present application is to provide a high-nickel positive electrode material, which has a low degree of lithium-nickel mixing, a low cycle DCR, and a high cycle capacity.

[0008] The second object of this application is to provide a method for preparing a high-nickel positive electrode material.

[0009] The third object of this application is to provide a positive electrode plate.

[0010] A fourth object of the present application is to provide a lithium-ion battery.

[0011] The fifth purpose of this application is to provide an electrical device.

[0012] In order to achieve the above-mentioned purpose of this application, the following technical solutions are specially adopted:

[0013] The present application first provides a high nickel cathode material, the general formula of which is Li m Ni x Co y Mn z Q i A j E k O2;

[0014] Among them, 0.98≤m≤1.05, 0.74≤x≤0.98, 0≤y≤0.2, 0≤z≤0.2, 0.001≤i≤0.2, 0.002≤j≤0.09, 0.001≤k≤0.06, and x+y+z+i+j+k=1; Q includes at least one of Zr, B and Al elements, A includes at least one of F, Ca, La and Ru elements, and E includes at least one of Na, Ag and Mg elements.

[0015] Preferably, 0.8≤x≤0.98.

[0016] Preferably, the ratio of the diffraction peak intensity of the (003) crystal plane to the diffraction peak intensity of the (104) crystal plane of the high-nickel positive electrode material is I(003) / I(104)≥3.5.

[0017] Preferably, the ratio of the sum of the diffraction peak intensities of the (006) crystal plane and the (012) crystal plane of the high-nickel positive electrode material to the diffraction peak intensity of the (101) crystal plane [I(006)+I(012)] / I(101)≤0.291.

[0018] Preferably, the lithium-nickel mixing ratio of the high-nickel positive electrode material is ≤0.017.

[0019] Preferably, the high-nickel positive electrode material contains a bonded ion cluster structure.

[0020] Preferably, in the high nickel cathode material, element Q is at least partially enriched in Ni 2+ Around and with Ni 2+ The bonded ion cluster structure is formed.

[0021] Preferably, the unit cell volume of the high nickel cathode material is ≥

[0022] The present application also provides a method for preparing a high-nickel positive electrode material, comprising the following steps:

[0023] A mixed salt solution containing Ni and Q elements is mixed with a complexing agent solution and a precipitant solution and subjected to a coprecipitation reaction, wherein the mixed salt solution also includes Co and / or Mn elements; after the coprecipitation reaction is completed, a chemical formula of Ni is obtained. x Co y Mn z Q i (OH)2 precursor material; wherein 0.8≤x≤0.98, 0≤y≤0.2, 0≤z≤0.2, 0.001≤i≤0.2; Q comprises at least one of Zr, B and Al elements;

[0024] calcining the precursor material to pre-treat it, so that the doping element Q enters the interlayer structure of the precursor material to obtain a pre-treated material;

[0025] The pretreated material is mixed with a lithium source, an A-containing dopant, and an E-containing dopant and then sintered to obtain the high-nickel positive electrode material; wherein A includes at least one of F, Ca, La, and Ru elements; and E includes at least one of Na, Ag, and Mg elements.

[0026] Preferably, the temperature of the calcination pretreatment is 300-600°C.

[0027] Preferably, the calcination pretreatment is carried out in an atmosphere with an oxygen volume fraction of ≤21% by volume.

[0028] Preferably, the sintering temperature is 500-800°C.

[0029] Preferably, the sintering is performed in an atmosphere with an oxygen volume fraction of ≥21% by volume.

[0030] Preferably, the sintering specifically includes: first keeping the temperature at 500-700° C. for 2-5 hours, and then keeping the temperature at 710-800° C. for 8-10 hours.

[0031] Preferably, the coprecipitation reaction temperature is 55-65°C.

[0032] Preferably, the coprecipitation reaction time is 12 to 24 hours.

[0033] Preferably, the pH of the mixed material during the coprecipitation reaction is 10-11.

[0034] Preferably, the A-containing dopant comprises an A-containing compound;

[0035] Preferably, the E-containing dopant includes an E-containing compound.

[0036] Preferably, the Q element is provided by a Q source, and the Q source includes at least one of ZrO2, B2O3 and Al2O3.

[0037] The present application further provides a positive electrode plate, which is mainly made of the high-nickel positive electrode material.

[0038] The present application further provides a lithium-ion battery, comprising the aforementioned positive electrode plate.

[0039] The present application further provides an electrical device comprising the lithium-ion battery.

[0040] Compared with the prior art, the present invention has the following advantages:

[0041] (1) The high nickel cathode material provided by this application can fundamentally reduce Ni by introducing doping stabilizing elements Q, fast ion transport elements E and large ion radius elements A. 2+ Enter Li + The resulting high lithium-nickel mixed arrangement phenomenon stabilizes the layered crystal structure of the high nickel positive electrode material, improves the high temperature stability and rate performance of the high nickel positive electrode material, and reduces the cycle DCR of the high nickel positive electrode material.

[0042] (2) The preparation method of the high nickel positive electrode material provided in the present application introduces the stabilizing element Q in the precursor preparation process and performs calcination pretreatment on the precursor material, which can decompose the stabilizing element compound and enter the internal interlayer structure of the precursor to obtain a positive electrode precursor material in which the stabilizing element Q and nickel, cobalt and manganese are uniformly distributed; at the same time, the calcination pretreatment can enrich the stabilizing element Q in the precursor material in the Ni 2+ Around and with Ni 2+ Forming ionic bonding, increasing the ionic radius of the bonded ions, when the positive electrode material is repeatedly charged and discharged, the Ni 2+ Stable in the original position, fundamentally reducing Ni 2+ Enter Li + The resulting high lithium-nickel mixing phenomenon stabilizes the layered crystal structure of the high nickel positive electrode material, improves the cycle and rate performance of the high nickel positive electrode material, and reduces the cycle DCR of the high nickel positive electrode material.

[0043] (3) The preparation method of the high nickel positive electrode material provided in the present application is to introduce doping elements A and E by adding A-containing dopant and E-containing dopant, wherein the element A with a large ion radius can be embedded in the layered positive electrode material to increase the bonding ion group and Li + The spacing between them is increased.+ transport path, and further reduce the bonded ion clusters to Li + The fast ion transport element E forms a low eutectic at a lower temperature, and synergistically acts with the large ion radius element A to enable lithium ions to diffuse rapidly at a relatively low temperature, reducing energy consumption while improving ionic conductivity, promoting the entry of lithium ions into the precursor, improving the high temperature stability and cycle capacity of the high nickel cathode material, and further reducing the cycle DCR of the high nickel cathode material. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] In order to more clearly illustrate the specific implementation methods of the present application or the technical solutions in the prior art, the following is a brief introduction to the drawings required for use in the specific implementation methods or the description of the prior art. Obviously, the drawings described below are some implementation methods of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0045] FIG1 is a crystal structure model diagram of the high nickel cathode material provided in this application;

[0046] FIG2 is a SEM image of the precursor material prepared in Example 1 provided in this application;

[0047] FIG3 is a SEM image of the high-nickel positive electrode material prepared in Example 1 provided in this application;

[0048] FIG4 is a bar graph of cycle DCR tests of batteries made from the positive electrode materials of the embodiments and comparative examples provided in this application. DETAILED DESCRIPTION

[0049] The technical scheme of the present application will be clearly and completely described below in conjunction with the accompanying drawings and specific embodiments, but it will be understood by those skilled in the art that the following described embodiments are part of the present application's embodiments, rather than all of the embodiments, and are only used to illustrate the present application, and should not be considered as limiting the scope of the present application. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without making creative work are within the scope of protection of the present application. Those who do not specify specific conditions in the embodiments are carried out according to conventional conditions or the conditions recommended by the manufacturer. Those whose reagents or instruments are not specified as manufacturers are conventional products that can be purchased commercially.

[0050] Unless otherwise specified, the terms "include" and "comprising" used in this application may be open-ended or closed-ended. For example, "include" and "comprising" may mean that other components not listed may also be included or that only the listed components are included.

[0051] Unless otherwise specified, the term "or" is used in this application to be inclusive. For example, the phrase "A or B" means "A, B, or both A and B." More specifically, the condition "A or B" is satisfied if any of the following conditions are met: A is true (or exists) and B is false (or does not exist); A is false (or does not exist) and B is true (or exists); or both A and B are true (or exist).

[0052] Unless otherwise specified, in this application, "one or more" or "at least one" refers to any one, any two, or any two or more of the listed items. Among them, "several" refers to any two or any two or more.

[0053] Unless otherwise specified, in this application, terms such as "first aspect," "second aspect," "third aspect," and "fourth aspect" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or quantity, nor as implicitly indicating the importance or quantity of the technical features indicated. Furthermore, terms such as "first," "second," "third," and "fourth" serve only as non-exhaustive enumeration and description, and should not constitute a closed-ended limitation on quantity.

[0054] In the first aspect, the present application provides a high nickel cathode material with a low cycle DCR (direct current internal resistance) having a bonded ion group structure, the general formula of the high nickel cathode material is Li m Ni x Co y Mn z Q i A j E k O2, the high nickel positive electrode material has a layered structure, and Q, A and E are doped as doping elements inside the high nickel positive electrode material.

[0055] The above general formula Li m Ni x Co y Mn z Q i A j E k In O2, 0.98≤m≤1.05, 0.74≤x≤0.98, 0≤y≤0.2, 0≤z≤0.2, 0.001≤i≤0.2, 0.002≤j≤0.09, 0.001≤k≤0.06, and x+y+z+i+j+k=1.

[0056] Wherein, the value of m includes but is not limited to any one of 0.98, 0.99, 1.00, 1.01, 1.02, 1.03, 1.04, and 1.05, or a range of values ​​between any two of them; the value of x includes but is not limited to any one of 0.74, 0.745, 0.781, 0.8, 0.83, 0.85, 0.88, 0.90, 0.93, 0.95, and 0.98, or a range of values ​​between any two of them; the value of y includes but is not limited to any one of 0, 0.01, 0.03, 0.05, 0.08, 0.1, 0.12, 0.15, 0.17, 0.19, and 0.2, or a range of values ​​between any two of them; the value of z includes but is not limited to 0, 0.01, 0.03, 0.05, 0.08, 0.1, 0.12, 0.15, 0.17 , 0.19, 0.2 or any range between them; the value of i includes but is not limited to any one of 0.001, 0.003, 0.005, 0.008, 0.01, 0.03, 0.05, 0.08, 0.1, 0.12, 0.15, 0.17, 0.19, 0.2 or any range between them; the value of j includes but is not limited to any one of 0.002, 0.003, 0.005, 0.008, 0.01, 0.03, 0.05, 0.07, 0.09 or any range between them; the value of k includes but is not limited to any one of 0.001, 0.003, 0.005, 0.008, 0.01, 0.02, 0.03, 0.05, 0.06 or any range between them.

[0057] The above general formula Li m Ni x Co y Mn z Q i A j E k In O2, Q includes at least one of Zr, B and Al, A includes at least one of F, Ca, La and Ru, and E includes at least one of Na, Ag and Mg.

[0058] The high nickel cathode material provided in this application is enriched in Ni by introducing the doping stabilizing element Q. 2+ Around and with Ni 2+ Form bonded ion clusters and increase the ionic radius of bonded ions, so that when the positive electrode material is repeatedly charged and discharged, the Ni 2+ Stable in the original position, fundamentally reducing Ni 2+ Enter Li +The resulting high lithium-nickel mixing phenomenon stabilizes the layered crystal structure of the high nickel positive electrode material, improves the cycle and rate performance of the high nickel positive electrode material, and reduces the cycle DCR of the high nickel positive electrode material.

[0059] At the same time, the high nickel cathode material is introduced into the large ion radius element A and the fast ion transport element E, wherein the doping of the large ion radius element A further increases the bonding ion group and Li + The spacing between the two elements further reduces the possibility of lithium nickel mixing, and the fast ion transport element E and the large ion radius element A work together to make Li + It diffuses rapidly at relatively low temperatures, reduces energy consumption while improving ionic conductivity, promotes the entry of lithium ions into the precursor, improves the high-temperature stability and cycle capacity of the high-nickel positive electrode material, and further reduces the cycle DCR of the high-nickel positive electrode material.

[0060] In a preferred embodiment, 0.8≤x≤0.98, and the value of x includes but is not limited to any point value of 0.8, 0.83, 0.85, 0.88, 0.90, 0.93, 0.95, 0.98, or a range of values ​​between any two of them.

[0061] In some specific embodiments, the ratio of the diffraction peak intensity of the (003) crystal plane of the high nickel positive electrode material to the diffraction peak intensity of the (104) crystal plane I(003) / I(104) is ≥3.50, including but not limited to any one of 3.51, 3.52, 3.53, 3.54, 3.55, 3.56, 3.57, 3.58, 3.59, and 3.60 or the range between any two of them. That is, in the X-ray diffraction pattern of the high nickel positive electrode material, the ratio of the (003) peak height to the (104) peak height I(003) / I(104) is ≥3.50.

[0062] The higher the ratio I(003) / I(104), the lower the degree of lithium-nickel intermixing. The high-nickel cathode material provided in this application has an I(003) / I(104) of ≥3.50, indicating a low degree of lithium-nickel intermixing.

[0063] In some specific embodiments, the ratio of the sum of the diffraction peak intensities of the (006) crystal plane and the (012) crystal plane of the high-nickel positive electrode material to the diffraction peak intensity of the (101) crystal plane [I(006)+I(012)] / I(101)≤0.291, including but not limited to any one of 0.291, 0.290, 0.289, 0.288, 0.287, 0.286, 0.285, 0.283, 0.280 or the range value between any two of them.

[0064] The lower the ratio [I(006)+I(012)] / I(101), the lower the degree of lithium-nickel intermixing. The high-nickel cathode material provided in this application has [I(006)+I(012)] / I(101) ≤ 0.291, indicating a low degree of lithium-nickel intermixing.

[0065] In some specific embodiments, the lithium-nickel mixing ratio of the high-nickel positive electrode material is ≤0.017, including but not limited to any one of 0.017, 0.0169, 0.0168, 0.0167, 0.0166, and 0.0165, or a range between any two of them.

[0066] The lower the lithium-nickel intermixing ratio, the lower the degree of lithium-nickel intermixing. The lithium-nickel intermixing ratio of the high-nickel positive electrode material provided in this application is ≤0.017, which indicates that the lithium-nickel intermixing degree of the positive electrode material is low.

[0067] In some specific embodiments, the high-nickel positive electrode material contains a bonded ion cluster structure.

[0068] In some specific embodiments, in the high nickel cathode material, element Q is at least partially enriched in Ni 2+ Around and with Ni 2+ The bonded ion group structure is formed to increase the ion radius of the bonded ion group structure, so that when the positive electrode material is repeatedly charged and discharged and lithium is inserted and removed, Ni 2+ Stable in the original position, fundamentally reducing Ni 2+ Enter Li + The resulting high lithium-nickel mixing phenomenon stabilizes the layered crystal structure of the high nickel positive electrode material, improves the cycle and rate performance of the high nickel positive electrode material, and reduces the cycle DCR of the high nickel positive electrode material.

[0069] In some specific embodiments, in the high nickel cathode material, element A increases the bonding ion group structure and Li + The spacing between them further reduces the possibility of lithium and nickel mixing.

[0070] In some specific embodiments, in the high nickel cathode material, element E and element A synergistically increase Li + The diffusion rate of Li + Rapid diffusion at relatively low temperatures reduces energy consumption while improving ionic conductivity and promoting Li + Entering into the precursor, it improves the high temperature stability and cycle capacity of the high nickel cathode material, and further reduces the cycle DCR of the high nickel cathode material.

[0071] In some specific embodiments, the unit cell volume of the high nickel cathode material is ≥

[0072] In a second aspect, the present application provides a method for preparing the high-nickel positive electrode material, which specifically comprises the following steps:

[0073] Precursor preparation: a mixed salt solution containing Ni and Q elements is mixed with a complexing agent solution and a precipitant solution, and a coprecipitation reaction is carried out. After the coprecipitation reaction is completed, the solid and liquid are separated to obtain a product with the chemical formula Ni x Co y Mn z Q i Precursor material for (OH)2.

[0074] The mixed salt solution further includes Co and / or Mn elements. That is, the mixed salt solution may not contain Co and Mn elements, may contain Co or Mn elements, or may contain both Co and Mn elements. Whether to introduce Co and Mn elements can be determined as needed.

[0075] The above chemical formula Ni x Co y Mn z Q i In (OH)2, 0.8≤x≤0.98, 0≤y≤0.2, 0≤z≤0.2, and 0.001≤i≤0.2. The value of x includes but is not limited to any one of 0.8, 0.83, 0.85, 0.88, 0.90, 0.93, 0.95, and 0.98, or any range between two of them; the value of y includes but is not limited to any one of 0, 0.01, 0.03, 0.05, 0.08, 0.1, 0.12, 0.15, 0.17, 0.19, and 0.2, or any range between two of them; the value of z includes but is not limited to 0, 0.0 1, 0.03, 0.05, 0.08, 0.1, 0.12, 0.15, 0.17, 0.19, 0.2, or any range between them; the value of i includes but is not limited to 0.001, 0.003, 0.005, 0.008, 0.01, 0.03, 0.05, 0.08, 0.1, 0.12, 0.15, 0.17, 0.19, 0.2, or any range between them.

[0076] The above chemical formula Ni x Co y Mn z Q i In (OH)2, Q includes at least one of Zr element, B element and Al element.

[0077] Precursor pretreatment: The precursor material prepared above is calcined to allow the doping element Q to enter the interlayer structure of the precursor material, and then cooled to obtain a pretreated material, the chemical formula of which is Ni x Co y Mn z Q i (OH)2.

[0078] The purpose of the above-mentioned calcination pretreatment is to allow the stabilizing element Q to enter the internal interlayer structure of the precursor, thereby obtaining a positive electrode precursor material in which the stabilizing element Q and nickel, cobalt and manganese are evenly distributed.

[0079] It is understandable that before pretreatment, some Q-containing compounds are mixed in the layered structure, but their embedding and arrangement are not regular, and most of the Q-containing compounds are concentrated at the edges and outside of the layered structure. However, the calcination pretreatment step provided in the present application can ensure that the Q element is regularly embedded in the layered structure.

[0080] Preparation of high nickel cathode material: The pretreated material prepared above is mixed with lithium source, A-containing dopant and E-containing dopant, and sintered, and then cooled to obtain the high nickel cathode material, whose chemical formula is Li m Ni x Co y Mn z Q i A j E k O2.

[0081] The A element in the A-containing dopant includes at least one of F, Ca, La and Ru.

[0082] The E element in the E-containing dopant includes at least one of Na, Ag, and Mg.

[0083] The above preparation method introduces the stabilizing element Q during the precursor preparation process and performs calcination pretreatment on the precursor material, which can decompose the stabilizing element compound and enter the internal interlayer structure of the precursor, thereby obtaining a positive electrode precursor material with a uniform distribution of the stabilizing element Q and nickel, cobalt and manganese. Among them, the calcination pretreatment can further enrich the stabilizing element Q inside the precursor material in the Ni 2+ Around and with Ni 2+ Forming ionic bonding, increasing the ionic radius of the bonded ions, when the positive electrode material is repeatedly charged and discharged, the Ni 2+ Stable in the original position, fundamentally reducing Ni 2+ Enter Li +The high lithium-nickel mixing phenomenon brought about stabilizes the layered crystal structure of the high nickel positive electrode material, enhances the cycle and rate performance of the high nickel positive electrode material, and reduces the cycle DCR of the high nickel positive electrode material.

[0084] Furthermore, the present invention mixes the pretreated material with a lithium source, an A-containing dopant and an E-containing dopant and sintering them, wherein the large ion radius element A can be embedded in the layered positive electrode material to expand the Li + transport path, and further reduce the bonded ion clusters to Li + At the same time, the fast ion transport element E forms a low eutectic at a lower temperature, and synergistically acts with the large ion radius element A, so that lithium ions diffuse rapidly at a relatively low temperature, reducing energy consumption while improving ionic conductivity, promoting the entry of lithium ions into the precursor, and improving the high temperature stability and cycle capacity of the high nickel cathode material, thereby reducing the cycle DCR of the high nickel cathode material.

[0085] As shown in FIG1 , after the precursor material obtained by the coprecipitation reaction is calcined and pretreated, the doping element Q is enriched in the Ni 2+ Around and with Ni 2+ Form a bonded ion cluster whose ionic radius is larger than Li + Radius, then add A source and E source sintering, by doping the large ion radius element A further increase the bonding ion group and Li + spacing, reducing the possibility of mixing the two, and fundamentally reducing Ni 2+ Enter Li + The resulting high lithium-nickel mixing phenomenon stabilizes the layered crystal structure of the material, improves the cycle and rate performance of the material, and reduces the cycle DCR of the high-nickel positive electrode material; at the same time, the fast ion transport element E is used to diffuse rapidly at a relatively low temperature, reducing energy consumption while improving ionic conductivity, promoting the entry of lithium ions into the precursor, improving the high-temperature stability and cycle capacity of the high-nickel positive electrode material, and further reducing the cycle DCR of the high-nickel positive electrode material.

[0086] Therefore, the preparation method of the high nickel positive electrode material provided in this application first obtains Ni by Q doping and calcination pretreatment. 2+ A stable positive electrode precursor material was then prepared through the synergistic effect of the large ion radius element A and the fast ion transport element E to obtain a ternary high-nickel positive electrode material with a low cycle DCR and a bonded ion cluster structure.

[0087] In the above process of preparing high nickel cathode material, the ratio of each raw material satisfies the general formula Li m Ni x Co y Mn z Q i A jE k O2, wherein 0.98≤m≤1.05, 0.8≤x≤0.98, 0≤y≤0.2, 0≤z≤0.2, 0.001≤i≤0.2, 0.002≤j≤0.09, 0.001≤k≤0.06, and x+y+z+i+j+k=1.

[0088] In some specific embodiments, the A-containing dopant includes an A-containing compound.

[0089] For example, the compound containing A includes at least one of AlF 3 , CaO, CaO 2 , La 2 O 3 , LaOH, and RuO 2 , but is not limited thereto.

[0090] In some specific embodiments, the E-containing dopant includes an E-containing compound.

[0091] For example, the compound containing E includes at least one of NaO 2 , NaOH, Na 2 CO 3 , AgNO 3 , MgO, and Mg 2 O 3 , but is not limited thereto.

[0092] In some specific embodiments, the temperature of the calcination pretreatment is 300-600°C, including but not limited to any one of 300°C, 350°C, 400°C, 450°C, 500°C, 550°C, and 600°C, or a range between any two of them.

[0093] By adopting the above-mentioned calcination pretreatment temperature range, the Q compound can be decomposed and enter the internal interlayer structure of the precursor, thereby obtaining a positive electrode precursor material in which the stabilizing element Q and nickel, cobalt or manganese elements are evenly distributed.

[0094] In some specific embodiments, the holding time of the calcination pretreatment is 3 to 10 hours, including but not limited to any one of 3 hours, 3.5 hours, 4 hours, 4.5 hours, 5 hours, 5.5 hours, 6 hours, 7 hours, 8 hours, and 10 hours, or a range between any two of the points.

[0095] In some specific embodiments, the calcination pretreatment is carried out in an atmosphere with an oxygen volume fraction ≤21% by volume, wherein the oxygen volume fraction ≤21% includes but is not limited to any one of 21%, 20%, 18%, 15%, 13%, 10%, 7%, 5%, 3%, 1%, 0% or a range between any two of them.

[0096] The calcination pretreatment adopts the above temperature range and the above atmosphere to ensure that the material remains Ni after pretreatment. x Co y Mn z Q i (OH)2, to avoid the formation of oxide positive electrode materials.

[0097] In some specific embodiments, the atmosphere of the calcination pretreatment includes at least one of an air atmosphere, a nitrogen atmosphere, and an argon atmosphere, or a mixture of air and an inert atmosphere.

[0098] In some specific embodiments, the gas pressure during the calcination pretreatment is 0.1-0.3 MPa, including but not limited to any one of 0.1 MPa, 0.2 MPa, and 0.3 MPa, or a range between any two of them.

[0099] In some specific embodiments, the sintering temperature is 500-800°C, including but not limited to any one of 500°C, 550°C, 600°C, 650°C, 700°C, 750°C, 800°C or a range between any two of them.

[0100] By adopting the above sintering temperature range, a layered oxide high-nickel positive electrode material can be obtained, and at the same time, the A element and the E element can be doped into the crystal lattice.

[0101] In some specific embodiments, the sintering holding time is 3 to 15 hours, including but not limited to any one of 3 hours, 3.5 hours, 4 hours, 4.5 hours, 5 hours, 5.5 hours, 6 hours, 7 hours, 8 hours, 9 hours, 10 hours, 11 hours, 13 hours, and 15 hours, or a range between any two of them.

[0102] In some specific implementations, the sintering specifically includes: first keeping the temperature at 500-700° C. for 2-5 hours, and then keeping the temperature at 710-800° C. for 8-10 hours.

[0103] The two-step sintering process involves decomposing the raw materials at a temperature of 500-700°C, removing some impurities and making the raw materials purer and more stable. The second step, sintering, converts the decomposed raw materials into the target material and stabilizes it.

[0104] In some specific embodiments, the sintering is carried out in an atmosphere with an oxygen volume fraction ≥21% by volume, wherein the oxygen volume fraction ≥21% includes but is not limited to any point value of 21%, 22%, 23%, 25%, 30%, 40%, 50%, 60%, 70%, 80%, 100% or a range value between any two of them.

[0105] In some specific embodiments, the sintering atmosphere includes air atmosphere and / or oxygen atmosphere.

[0106] In some specific embodiments, the sintering gas pressure is 0.1-0.3 MPa, including but not limited to any one of 0.1 MPa, 0.2 MPa, and 0.3 MPa, or a range between any two of them.

[0107] In some specific embodiments, after the sintering, the steps of crushing, screening and iron removal are further performed in sequence.

[0108] In some specific embodiments, during the process of mixing the pretreated material with the lithium source, the A-containing dopant and the E-containing dopant, the temperature of the mixed material is ≤60°C, including but not limited to any one of 60°C, 50°C, 40°C, 30°C, 20°C, 10°C or a range between any two of them.

[0109] In some specific embodiments, the lithium source may be any conventional lithium-containing compound, such as at least one of Li2CO3, LiOH, LiOH·H2O, and CH3COOLi, but is not limited thereto.

[0110] In some specific embodiments, the coprecipitation reaction temperature is 55-65°C, including but not limited to any one of 55°C, 57°C, 59°C, 60°C, 62°C, 64°C, and 65°C, or a range between any two of them.

[0111] In some specific embodiments, the coprecipitation reaction time is 12 to 24 hours, including but not limited to any one of 12 hours, 15 hours, 18 hours, 20 hours, 22 hours, and 24 hours, or a range between any two of them.

[0112] In some specific embodiments, the pH of the mixed material during the coprecipitation reaction is 10-11, including but not limited to any one of 10.0, 10.2, 10.4, 10.5, 10.7, 10.9, 11.0 or a range between any two of them.

[0113] By adopting the above-mentioned co-precipitation reaction temperature, time and pH, a precursor with higher purity and less impurities can be obtained.

[0114] In some specific embodiments, the coprecipitation reaction is carried out in a reactor.

[0115] In some specific embodiments, the method for preparing the mixed salt solution includes: mixing a nickel source solution and a Q source solution, and optionally, adding a cobalt source solution and / or a manganese source solution during the mixing process.

[0116] In some specific embodiments, in the mixed salt solution, the molar ratio of Ni element, Co element, Mn element and Q element is (0.8-0.98):(0-0.2):(0-0.2):(0.001-0.2).

[0117] The nickel source may be any conventional nickel-containing compound, such as at least one of nickel sulfate, nickel nitrate and nickel chloride, but is not limited thereto.

[0118] The cobalt source may be any conventional cobalt-containing compound, such as at least one of cobalt sulfate, cobalt nitrate and cobalt chloride, but is not limited thereto.

[0119] The manganese source may be any conventional manganese-containing compound, such as at least one of manganese sulfate, manganese nitrate and manganese chloride, but is not limited thereto.

[0120] The Q source includes a compound containing a Q element, such as an oxide.

[0121] The use of oxides is beneficial to reducing the impurity content in the positive electrode material.

[0122] As an example, the Q source includes, but is not limited to, at least one of ZrO 2 , B 2 O 3 , and Al 2 O 3 .

[0123] In some specific embodiments, the complexing agent solution comprises an aqueous ammonia solution.

[0124] In some specific embodiments, the precipitant solution comprises a sodium hydroxide solution.

[0125] In some specific embodiments, the molar ratio of the pretreated material, the Li element in the lithium source, the A element in the A-containing dopant, and the E element in the E-containing dopant is 1:(0.98-1.05):(0.002-0.09):(0.001-0.06).

[0126] In a third aspect, the present application provides a positive electrode plate comprising the high-nickel positive electrode material.

[0127] In some specific embodiments, the positive electrode plate includes a current collector and a positive electrode material coated on the current collector, wherein the positive electrode material is mainly made of the above-mentioned high-nickel positive electrode material, a binder and a conductive agent.

[0128] In some specific embodiments, the current collector for the positive electrode plate may be a metal foil or a composite current collector. For example, aluminum foil may be used as the metal foil. The composite current collector may include a polymer material base layer and a metal layer formed on at least one surface of the polymer material base layer. The composite current collector may be formed by forming a metal material on a polymer material substrate. Alternatively, the metal material may include but is not limited to one or more of aluminum, aluminum alloy, nickel, nickel alloy, titanium, titanium alloy, silver and silver alloy. Alternatively, the polymer material substrate may include but is not limited to one or more of polypropylene (PP), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polystyrene (PS) and polyethylene (PE).

[0129] In some specific embodiments, the binder for the positive electrode sheet may be any commercially available binder for positive electrode sheets, such as polyvinylidene fluoride (PVDF), or any binder prepared by prior art, but is not limited thereto.

[0130] As an example, the binder may include at least one of polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), vinylidene fluoride-tetrafluoroethylene-propylene terpolymer, vinylidene fluoride-fluoropropylene-tetrafluoroethylene terpolymer, tetrafluoroethylene-hexafluoropropylene copolymer, and fluorine-containing acrylate resin.

[0131] In some specific embodiments, the conductive agent used for the positive electrode plate can be any commercially available conductive agent for lithium-ion batteries, or any conductive agent prepared by existing technologies, such as carbon black, graphite, etc., but is not limited thereto.

[0132] As an example, the conductive agent may include at least one of carbon black, carbon dots, carbon nanotubes, graphene, and carbon nanofibers, wherein the carbon black includes superconducting carbon, acetylene black, or Ketjen black.

[0133] In some specific embodiments, the positive electrode plate can be prepared using a method commonly used in the art, or using any existing technology.

[0134] As an example, a positive electrode sheet can be prepared by dispersing the aforementioned components for preparing a positive electrode sheet, such as a positive electrode active material, a conductive agent, a binder, and any other components, in a solvent to form a positive electrode slurry; coating the positive electrode slurry on a positive electrode current collector, and performing drying, cold pressing, and other processes to obtain a positive electrode sheet. Optionally, the solvent includes, but is not limited to, N-methylpyrrolidone.

[0135] In a fourth aspect, the present application provides a lithium-ion battery comprising the aforementioned positive electrode plate.

[0136] The lithium-ion battery provided in this application has excellent rate performance and capacity retention, and has a low cycle DCR.

[0137] In some specific embodiments, the lithium-ion battery is mainly composed of the above-mentioned positive electrode sheet, negative electrode sheet, separator and electrolyte.

[0138] Among them, the negative electrode plate, separator and electrolyte can be made of any materials commonly used in the art, or materials available according to the prior art, and this application does not limit this.

[0139] In a fifth aspect, the present application provides an electrical device comprising the lithium-ion battery.

[0140] The above-mentioned electrical equipment includes any equipment that uses the above-mentioned lithium-ion battery, such as electric vehicles, electric motorcycles, electric bicycles, power tools, energy storage systems, electronic products, office equipment, etc., but is not limited thereto.

[0141] The embodiments of the present application will be described in detail below with reference to the examples, but it will be understood by those skilled in the art that the following examples are merely illustrative of the present application and should not be construed as limiting the scope of the present application. In the examples, if no specific conditions are specified, the conditions are followed according to conventional conditions or manufacturer recommendations. The reagents or instruments used are not specified by manufacturer and are all commercially available conventional products.

[0142] Example 1

[0143] The high nickel cathode material Li provided in this embodiment 1.04 Ni 0.781 Co 0.113 Mn 0.047 B 0.047 F 0.008 Al 0.003 Na 0.001 The preparation method of O2 comprises the following steps:

[0144] (1) Nickel sulfate, cobalt sulfate, manganese sulfate, B2O3, and water were mixed to form a mixed salt solution at a molar ratio of Ni:Co:Mn:B=0.79:0.114:0.048:0.048, and a sodium hydroxide solution with a molar concentration of 4.4 mol / L and an ammonia solution with a molar concentration of 2.2 mol / L were prepared.

[0145] The mixed salt solution, ammonia solution and sodium hydroxide solution were added to the reactor slowly and continuously at a flow ratio of 1:0.8:0.5, and a coprecipitation reaction was carried out at a temperature of 60°C and a pH of 10.5. After the reaction for 16 hours, the precipitate was filtered, washed and dried to obtain the precursor material Ni 0.79 Co 0.114 Mn 0.048 B 0.048 (OH)2.

[0146] (2) The precursor material prepared in step (1) is calcined at 400° C. in an air atmosphere for pretreatment, kept at this temperature for 8 hours, and then naturally cooled to room temperature to obtain a pretreated precursor material.

[0147] (3) According to the molar ratio of the pretreated precursor material: Li element: F element: Na element = 1:1.04:0.005:0.001, the pretreated precursor material obtained in step (2) was mixed with battery-grade lithium hydroxide monohydrate, AlF3 and NaO2, and then heated in an oxygen atmosphere at 2°C·min-1 The temperature was raised to 500℃ and kept at this temperature for 4h, then the temperature was raised to 500℃ at a rate of 2℃·min -1 The heating rate was raised to 770℃ and kept at this temperature for 10h, and then the temperature was raised to 770℃ at a rate of 3℃·min -1 The sintered material was subjected to coarse crushing, fine crushing, sieving and iron removal in sequence to obtain a high nickel positive electrode material Li 1.04 Ni 0.781 Co 0.113 Mn 0.047 B 0.047 F 0.008 Al 0.003 Na 0.001 O2.

[0148] Example 2

[0149] The high nickel cathode material Li provided in this embodiment 1.03 Ni 0.871 Co 0.1 Mn 0.02 Zr 0.002 Ca 0.002 Mg 0.005 The preparation method of O2 comprises the following steps:

[0150] (1) Nickel sulfate, cobalt sulfate, manganese sulfate, ZrO2, and water were mixed to form a mixed salt solution at a molar ratio of Ni:Co:Mn:Zr = 0.877:0.101:0.020:0.002, and a sodium hydroxide solution with a molar concentration of 4.4 mol / L and an ammonia solution with a molar concentration of 2.2 mol / L were prepared.

[0151] The mixed salt solution, ammonia solution and sodium hydroxide solution were added to the reactor slowly and continuously at a flow ratio of 1:0.8:0.5, and a coprecipitation reaction was carried out at a temperature of 62 ° C and a pH of 10.3. After the reaction for 18 hours, the precipitate was filtered, washed and dried to obtain the precursor material Ni 0.877 Co 0.101 Mn 0.020 Zr 0.002 (OH)2.

[0152] (2) The precursor material prepared in step (1) is calcined at 450° C. in an air atmosphere for pretreatment, kept at this temperature for 8 hours, and then naturally cooled to room temperature to obtain a pretreated precursor material.

[0153] (3) The pretreated precursor material obtained in step (2) was mixed evenly with battery-grade lithium hydroxide monohydrate, calcium oxide, and magnesium oxide according to the molar ratio of the pretreated precursor material: Li element: Ca element: Mg element = 1:1.03:0.002:0.005, and then heated in an oxygen atmosphere at 2°C·min -1 The temperature was raised to 530℃ and kept at this temperature for 3.5h, and then the temperature was raised to 530℃ at a rate of 2℃·min -1 The temperature was raised to 780℃ and kept at this temperature for 9h, and then the temperature was raised to 780℃ at a rate of 3℃·min -1 The sintered material was subjected to coarse crushing, fine crushing, sieving and iron removal in sequence to obtain a high nickel positive electrode material Li 1.03 Ni 0.871 Co 0.1 Mn 0.02 Zr 0.002 Ca 0.002 Mg 0.005 O2.

[0154] Example 3

[0155] The high nickel cathode material Li 0.98 Ni 0.745 Co 0.108 Mn 0.045 Al 0.045 Ru 0.038 Ag 0.019 The preparation method of O2 comprises the following steps:

[0156] (1) Nickel sulfate, cobalt sulfate, manganese sulfate, aluminum oxide, and water were mixed to form a mixed salt solution at a molar ratio of Ni:Co:Mn:Al of 0.79:0.114:0.048:0.048, and a sodium hydroxide solution with a molar concentration of 4.4 mol / L and an ammonia solution with a molar concentration of 2.2 mol / L were prepared.

[0157] The mixed salt solution, ammonia solution and sodium hydroxide solution were added to the reactor slowly and continuously at a flow ratio of 1:0.8:0.5. The coprecipitation reaction was carried out at a temperature of 63 ° C and a pH of 10.8. After 17 hours of reaction, the precipitate was filtered, washed and dried to obtain the precursor material Ni 0.79 Co 0.114 Mn 0.048 Al 0.048 (OH)2.

[0158] (2) The precursor material prepared in step (1) was pre-treated by calcination at 500° C. in a nitrogen atmosphere, kept warm for 8 h, and then naturally cooled to room temperature to obtain a pre-treated precursor material.

[0159] (3) According to the molar ratio of the pretreated precursor material: Li element: Ru element: Ag element = 1:0.98:0.038:0.019, the pretreated precursor material obtained in step (2) was mixed with battery-grade lithium hydroxide monohydrate, RuO2 and AgO, and then heated in an oxygen atmosphere at 2°C·min -1 The temperature was raised to 550℃ and kept at this temperature for 4h, and then the temperature was raised to 550℃ at a rate of 2℃·min -1 The heating rate was raised to 800℃ and kept at this temperature for 10h, and then the temperature was raised to 800℃ at a rate of 3℃·min -1 The sintered material was subjected to coarse crushing, fine crushing, sieving and iron removal in sequence to obtain a high nickel positive electrode material Li 0.98 Ni 0.745 Co 0.108 Mn 0.045 Al 0.045 Ru 0.038 Ag 0.019 O2.

[0160] Example 4

[0161] The high nickel positive electrode material LiNi provided in this embodiment 0.82 Mn 0.1 B 0.05 Ca 0.02 Ag 0.01 The preparation method of O2 comprises the following steps:

[0162] (1) Nickel nitrate, manganese nitrate, B2O3 and water were mixed to form a mixed salt solution at a molar ratio of Ni:Mn:B=84.5:10:5.5, and a sodium hydroxide solution with a molar concentration of 4.4 mol / L and an ammonia solution with a molar concentration of 2.2 mol / L were prepared.

[0163] The mixed salt solution, ammonia solution and sodium hydroxide solution were added to the reactor at a flow ratio of 1:0.8:0.5, and a coprecipitation reaction was carried out at a temperature of 60 ° C and a pH of 10. After the reaction for 15 hours, the precipitate was filtered, washed and dried to obtain the precursor material Ni 0.845 Mn 0.1 B 0.055 (OH)2.

[0164] (2) The precursor material prepared in step (1) was calcined at 520° C. in an air atmosphere for pretreatment, kept warm for 8 hours, and then naturally cooled to room temperature to obtain a pretreated precursor material.

[0165] (3) According to the molar ratio of the pretreated precursor material: Li element: Ca element: Ag element = 1:1:0.02:0.01, the pretreated precursor material obtained in step (2) was mixed with lithium acetate, calcium oxide and silver oxide, and then heated in an oxygen atmosphere at 2°C·min -1 The temperature was raised to 600℃ and kept at this temperature for 3h, then the temperature was raised to 600℃ at a rate of 2℃·min -1 The temperature was raised to 830℃ at a heating rate of 100℃ and kept at that temperature for 11h, and then the temperature was raised to 830℃ at a heating rate of 3℃·min - 1 The sintered material was subjected to coarse crushing, fine crushing, sieving and iron removal in sequence to obtain the high nickel positive electrode material LiNi 0.82 Mn 0.1 B 0.05 Ca 0.02 Ag 0.01 O2.

[0166] Example 5

[0167] The high nickel cathode material Li provided in this embodiment 1.02 Ni 0.822 Co 0.08 Al 0.008 La 0.05 Na 0.04 The preparation method of O2 comprises the following steps:

[0168] (1) Nickel chloride, cobalt chloride, aluminum oxide, and water were mixed to form a mixed salt solution at a molar ratio of Ni:Co:Al of 90:9:1, and a sodium hydroxide solution with a molar concentration of 4.4 mol / L and an ammonia solution with a molar concentration of 2.2 mol / L were prepared.

[0169] The mixed salt solution, ammonia solution and sodium hydroxide solution were added to the reactor slowly and continuously at a flow ratio of 1:0.8:0.5, and a coprecipitation reaction was carried out at a temperature of 65 ° C and a pH of 11. After the reaction for 20 hours, the precipitate was filtered, washed and dried to obtain the precursor material Ni 0.9 Co 0.09 Al 0.01 (OH)2.

[0170] (2) The precursor material prepared in step (1) is calcined at 350° C. in an air atmosphere for pretreatment, kept at this temperature for 8 hours, and then naturally cooled to room temperature to obtain a pretreated precursor material.

[0171] (3) According to the molar ratio of the pretreated precursor material: Li element: La element: Na element = 1:1.02:0.05:0.04, the pretreated precursor material obtained in step (2) was mixed with lithium carbonate, La2O3 and NaO2, and then heated in an oxygen atmosphere at 2°C·min -1 The temperature was raised to 600℃ and kept at this temperature for 3h, then the temperature was raised to 600℃ at a rate of 2℃·min -1 The heating rate was raised to 850℃ and kept at this temperature for 8h, and then the temperature was raised to 850℃ at a rate of 3℃·min - 1 The sintered material was subjected to coarse crushing, fine crushing, sieving and iron removal in sequence to obtain a high nickel positive electrode material Li 1.02 Ni 0.822 Co 0.08 Al 0.008 La 0.05 Na 0.04 O2.

[0172] Comparative Example 1

[0173] The preparation method of the high-nickel positive electrode material provided in this comparative example is basically the same as that of Example 1, except that the mixed salt solution in step (1) does not contain B2O3, and AlF3 is not added in step (3).

[0174] The chemical formula of the high nickel cathode material prepared in this comparative example is Li 1.04 Ni 0.829 Co 0.120 Mn 0.050 Na 0.001 O2.

[0175] Comparative Example 2

[0176] The preparation method of the high-nickel positive electrode material provided in this comparative example is basically the same as that of Example 1, except that the mixed salt solution in step (1) does not contain B2O3, and NaO2 is not added in step (3).

[0177] The chemical formula of the high nickel cathode material prepared in this comparative example is Li 1.04 Ni 0.826 Co 0.119 Mn 0.050 Na 0.005 O2.

[0178] Comparative Example 3

[0179] The preparation method of the high-nickel positive electrode material provided in this comparative example is basically the same as that in Example 1, except that B2O3 is replaced by an equal molar amount of MgO in step (1), and AlF3 is not added in step (3).

[0180] The chemical formula of the high nickel cathode material prepared in this comparative example is Li 1.04 Ni 0.789 Co 0.114 Mn 0.048 Mg 0.048 Na 0.001 O2.

[0181] Comparative Example 4

[0182] The preparation method of the high-nickel positive electrode material provided in this comparative example is basically the same as that in Example 1, except that B2O3 is replaced by an equal molar amount of MgO in step (1), and NaO2 is not added in step (3).

[0183] The chemical formula of the high nickel cathode material prepared in this comparative example is Li 1.04 Ni 0.782 Co 0.113 Mn 0.047 B 0.047 F 0.008 Al 0.003 O2.

[0184] Comparative Example 5

[0185] The preparation method of the high-nickel positive electrode material provided in this comparative example is basically the same as that in Example 1, except that in step (3), the molar ratio of the pretreated precursor material: Li element: F element: Na element is replaced with 1:1.04:0.01:0.007.

[0186] The chemical formula of the high nickel cathode material prepared in this comparative example is Li 1.04 Ni 0.771 Co 0.112 Mn 0.046 B 0.046 F 0.0136 Al 0.0045 Na 0.0069 O2.

[0187] Comparative Example 6

[0188] The preparation method of the high-nickel positive electrode material provided in this comparative example is basically the same as that in Example 1, except that B2O3 is replaced by an equimolar amount of MgO in step (1), and AlF3 and NaO2 are not added in step (3).

[0189] The chemical formula of the high nickel cathode material prepared in this comparative example is Li 1.04 Ni 0.790 Co 0.114 Mn 0.048 Mg 0.048 O2.

[0190] Comparative Example 7

[0191] The preparation method of the positive electrode material provided in this comparative example comprises the following steps:

[0192] (1) is basically the same as step (1) of Example 1, except that the mixed salt solution does not contain B2O3.

[0193] (2) The same as step (2) of Example 1.

[0194] (3) The pretreated precursor material obtained in step (2) was mixed with battery-grade lithium hydroxide monohydrate at a molar ratio of 1:1.04 and heated in an oxygen atmosphere with a concentration of 95% or more at 2°C / min. -1 The heating rate was 2℃·min, and the temperature was raised to 500℃ and kept for 4h; then the temperature was raised to 500℃ and kept for 4h; -1 Heat to 770℃, keep warm for 10h; then -1 The temperature was lowered to room temperature to obtain the sintered positive electrode material. The positive electrode material obtained after sintering was then mixed with NaO2 in a molar ratio of 1:0.001, and heated in an oxygen atmosphere with a concentration of more than 95% at 2°C / min. -1 The heating rate was 3℃·min, and the temperature was raised to 360℃ and kept for 18h; then the temperature was raised to 3℃·min -1 The temperature was lowered to room temperature to obtain a Na-coated positive electrode material.

[0195] Comparative Example 8

[0196] The preparation method of the positive electrode material provided in this comparative example is basically the same as that of comparative example 7, except that in step (3), NaO2 is replaced by AlF3.

[0197] The positive electrode material prepared in this comparative example is an Al and F coated positive electrode material.

[0198] Comparative Example 9

[0199] The preparation method of the positive electrode material provided in this comparative example comprises the following steps:

[0200] (1) is basically the same as step (1) of Example 1, except that B2O3 is replaced by an equal molar amount of MgO.

[0201] (2) and (3) are the same as steps (2) and (3) of Comparative Example 7.

[0202] The positive electrode material prepared in this comparative example is a Mg-doped, Na-coated positive electrode material.

[0203] Comparative Example 10

[0204] The preparation method of the positive electrode material provided in this comparative example comprises the following steps:

[0205] (1) is basically the same as step (1) of Example 1, except that B2O3 is replaced by an equal molar amount of MgO.

[0206] (2) and (3) are the same as steps (2) and (3) of Comparative Example 8.

[0207] The positive electrode material prepared in this comparative example is a positive electrode material doped with Mg and coated with F and Al.

[0208] Comparative Example 11

[0209] The preparation method of the positive electrode material provided in this comparative example is basically the same as that of comparative example 7, except that in step (3), NaO2 is replaced by an equimolar amount of B2O3.

[0210] The positive electrode material prepared in this comparative example is a B-coated positive electrode material.

[0211] Comparative Example 12

[0212] The preparation method of the positive electrode material provided in this comparative example comprises the following steps:

[0213] (1) and (2) are the same as steps (1) and (2) of Example 1.

[0214] 3) The process is substantially the same as step (3) of Comparative Example 7, except that the positive electrode material is uniformly mixed with AlF3 and NaO2 according to a molar ratio of positive electrode material: F element: Na element of 1:0.005:0.001.

[0215] The positive electrode material prepared in this comparative example is a positive electrode material coated with Al, F and Na.

[0216] Comparative Example 13

[0217] The preparation method of the positive electrode material provided in this comparative example is basically the same as that of comparative example 7, except that, in step (3), the positive electrode material is uniformly mixed with B2O3, AlF3 and NaO2 according to the molar ratio of positive electrode material: B element: F element: Na element = 1:0.005:0.005:0.001.

[0218] The positive electrode material prepared in this comparative example is a positive electrode material coated with B, Al, F and Na.

[0219] Comparative Example 14

[0220] The preparation method of the positive electrode material provided in this comparative example is basically the same as that of comparative example 5, except that step (2) is not provided, that is, the precursor material is not subjected to calcination pretreatment.

[0221] The differences between the above embodiments and comparative examples are shown in Table 1 below.

[0222] Table 1

[0223] Experimental Example 1

[0224] The precursor material and high nickel cathode material prepared in Example 1 were subjected to SEM examination, and the SEM images are shown in FIG2 and FIG3 , respectively. The contents of main elements in the precursor material and high nickel cathode material are shown in Table 2 and Table 3 , respectively.

[0225] Table 2

[0226] Table 3

[0227] It can be seen from Figures 2 and 3 and Tables 2 and 3 that the elements Q, A and E in the high-nickel positive electrode material are all doping elements, not coatings.

[0228] Experimental Example 2

[0229] XRD tests were performed on the positive electrode materials prepared in the above embodiments and comparative examples to obtain the unit cell parameters of each material, the ratio of the sum of the diffraction peak intensities of the (006) crystal plane and the (012) crystal plane to the diffraction peak intensity of the (101) crystal plane [I(006)+I(012)] / I(101), the ratio of the diffraction peak intensity of the (003) crystal plane to the diffraction peak intensity of the (104) crystal plane I(003) / I(104) and the Li / Ni mixing ratio, as shown in Table 4.

[0230] Table 4

[0231] It can be seen from Table 4 that the unit cell volume of the positive electrode materials prepared in each embodiment is larger than that of each comparative example, which indicates that the stabilizing element Q is enriched in Ni 2+ Around and with Ni 2+ A bonded ion cluster is formed, which increases the ionic radius of the bonded ion.

[0232] Furthermore, the ratio of the sum of the diffraction peak intensities of the (006) crystal plane and the (012) crystal plane of the positive electrode material prepared in each embodiment to the diffraction peak intensity of the (101) crystal plane [I(006)+I(012)] / I(101) is lower than that of the comparative examples, the ratio of the diffraction peak intensity of the (003) crystal plane to the diffraction peak intensity of the (104) crystal plane of the positive electrode material prepared in each embodiment I(003) / I(104) is higher than that of the comparative examples, and the lithium-nickel intermixing rate of the high-nickel positive electrode material prepared in each embodiment is significantly lower than that of the comparative examples, which indicates that the degree of lithium-nickel intermixing of the high-nickel positive electrode material prepared in the present application is low.

[0233] Experimental Example 3

[0234] The positive electrode materials prepared in the above Examples and Comparative Examples were fabricated into lithium-ion batteries and subjected to electrochemical performance testing (voltage range 2.8-4.25 V, 0.2C discharge rate). The results are shown in Figure 4 and Table 5. Specifically, Figure 4 is a bar chart of the cyclic DCR test of batteries prepared with the positive electrode materials of the Examples and Comparative Examples; Table 5 shows the capacity retention results after 500 cycles of batteries prepared with the positive electrode materials of the Examples and Comparative Examples.

[0235] Among them, the preparation method of the positive electrode sheet is as follows: the high nickel positive electrode materials prepared in each group: SP (conductive carbon black): KS-6 (conductive graphite): PVDF (polyvinylidene fluoride) are dissolved in NMP in a ratio of mass percentage = 94.5%: 2%: 1%: 2.5%, and stirred into a paste slurry. The resulting slurry is then coated on a 15μm thick aluminum foil current collector using a coating machine and roll-formed, dried in an oven at 125°C, and cut into positive electrode sheets of the required size.

[0236] The preparation method of the negative electrode sheet is as follows: graphite: SP: CMC (carboxymethyl cellulose): SBR (styrene-butadiene rubber) is dissolved in deionized water in a ratio of mass percentage = 95.5%: 1%: 1.5%: 2%, and stirred into a paste slurry by magnetic stirring. The resulting slurry is then coated on a 10μm thick copper foil current collector using a coating machine and roll-formed. It is then dried in an oven at 115°C and cut into negative electrode sheets of the required size.

[0237] The battery assembly method is as follows: the positive electrode sheet, separator PP and the negative electrode sheet prepared above are wound into the required battery cell, baked in an 85°C oven for 10 hours, wrapped with aluminum-plastic film, and the tabs are welded. After a short-circuit test, the battery is further baked for 20 hours to test the moisture content. After the test is qualified, the liquid injection, exhaust, sealing, pre-charging, formation, aging and other processes are carried out to obtain the required battery.

[0238] Table 5

[0239] As shown in Figure 4 and Table 5, the high nickel positive electrode prepared in Example 1 has a lower cycle DCR, better rate performance and capacity retention.

[0240] Although the present application has been illustrated and described using specific embodiments, it should be appreciated that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. Those skilled in the art should understand that the technical solutions described in the above embodiments may be modified, or some or all of the technical features therein may be replaced by equivalents, without departing from the spirit and scope of the present application. These modifications or replacements do not deviate from the essence of the corresponding technical solutions within the scope of the technical solutions of the embodiments of the present application. Therefore, this means that all such replacements and modifications within the scope of the present application are included in the appended claims.

Claims

1. High nickel cathode material, among which, The general formula of the high nickel positive electrode material is Li m Ni x Co y Mn z Q i A j E k O2; Among them, 0.98≤m≤1.05, 0.74≤x≤0.98, 0≤y≤0.2, 0≤z≤0.2, 0.001≤i≤0.2, 0.002≤j≤0.09, 0.001≤k≤0.06, and x+y+z+i+j+k=1; Q includes at least one of Zr, B and Al elements, A includes at least one of F, Ca, La and Ru elements, and E includes at least one of Na, Ag and Mg elements.

2. The high nickel cathode material according to claim 1, wherein: 0.8≤x≤0.98。 3. The high nickel cathode material according to claim 2, wherein: The ratio of the diffraction peak intensity of the (003) crystal plane of the high-nickel positive electrode material to the diffraction peak intensity of the (104) crystal plane is I(003) / I(104)≥3.

5.

4. The high nickel cathode material according to claim 2, wherein: The ratio of the sum of the diffraction peak intensities of the (006) crystal plane and the (012) crystal plane of the high-nickel positive electrode material to the diffraction peak intensity of the (101) crystal plane [I(006)+I(012)] / I(101)≤0.

291.

5. The high nickel cathode material according to claim 2, wherein: The lithium-nickel mixing rate of the high-nickel positive electrode material is ≤0.

017.

6. The high nickel cathode material according to claim 2, wherein: The high-nickel positive electrode material contains a bonded ion cluster structure.

7. The high nickel positive electrode material according to claim 6, wherein: In the high nickel positive electrode material, element Q is at least partially enriched in Ni 2+ Around and with you 2+ The bonded ion cluster structure is formed.

8. The high nickel cathode material according to claim 2, wherein: Said 9. The method for preparing a high-nickel positive electrode material according to any one of claims 1 to 8, wherein: The steps include: A mixed salt solution containing Ni and Q elements is mixed with a complexing agent solution and a precipitant solution to carry out a coprecipitation reaction, wherein the mixed salt solution also includes Co and / or Mn elements; after the coprecipitation reaction is completed, a solution with a chemical formula of Ni x Co y Mn z Q i (OH)2 precursor material; wherein 0.8≤x≤0.98, 0≤y≤0.2, 0≤z≤0.2, 0.001≤i≤0.2; Q comprises at least one of Zr, B and Al elements; The precursor material is pre-treated by calcination, so that the doping element Q enters the interlayer structure of the precursor material to obtain a pre-treated material; The pretreated material is mixed with a lithium source, an A-containing dopant and an E-containing dopant and then sintered to obtain the high-nickel positive electrode material; wherein A includes at least one of F, Ca, La and Ru elements; and E includes at least one of Na, Ag and Mg elements.

10. The method for preparing a high nickel positive electrode material according to claim 9, wherein: The temperature of the calcination pretreatment is 300-600°C; And / or, the calcination pretreatment is carried out in an atmosphere with an oxygen volume fraction of ≤21% by volume.

11. The method for preparing a high-nickel positive electrode material according to claim 9, wherein: The sintering temperature is 500-800°C; And / or, the sintering is carried out in an atmosphere with an oxygen volume fraction of ≥ 21% by volume.

12. The method for preparing a high-nickel positive electrode material according to claim 9, wherein: The sintering specifically includes: firstly keeping the temperature at 500-700° C. for 2-5 hours, and then keeping the temperature at 710-800° C. for 8-10 hours.

13. The method for preparing a high-nickel positive electrode material according to claim 9, wherein: The coprecipitation reaction satisfies at least one of the following conditions: (1) The temperature of the coprecipitation reaction is 55-65° C.; (2) The coprecipitation reaction time is 12 to 24 hours; (3) The pH of the mixed material during the coprecipitation reaction is 10-11.

14. The method for preparing a high-nickel positive electrode material according to claim 9, wherein: At least one of the following conditions is met: (1) The A-containing dopant includes an A-containing compound; (2) The E-containing dopant includes a compound containing E; (3) The Q element is provided by a Q source, and the Q source includes at least one of ZrO2, B2O3 and Al2O3.

15. Positive electrode, wherein: Including the high-nickel positive electrode material as described in any one of claims 1 to claim 8.

16. Lithium-ion batteries, wherein: Comprising the positive electrode sheet as described in claim 15.

17. Electrical equipment, including: Comprising the lithium ion battery as claimed in claim 16.

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