A multi-element doped ultra-high nickel cathode material, its preparation method and application

Abstract

This invention provides a multi-element doped ultra-high nickel cathode material, its preparation method, and its application. The chemical formula of the multi-element doped ultra-high nickel cathode material is LiNi. x Mn y Mo a Nb b Zr c W d O2, where 0.85≤x≤0.90, 0.03≤y≤0.08, 0.01≤a≤0.03, 0.01≤b≤0.02, 0.005≤c≤0.015, 0.005≤d≤0.015. This invention uses Mo, Nb, Zr, and W as doping elements to achieve uniform multi-element doping throughout the entire particle from the core to the surface, synergistically leveraging lattice broadening and electron delocalization: by broadening the Li interlayer spacing, it enhances Li... ＋ The diffusion coefficient is reduced by forming wide-bandgap delocalized states in Li. ＋ The insertion / extraction barrier, combined with pinning to suppress oxygen evolution, jointly achieves the fast ion conductor effect, resulting in cathode materials with superior discharge capacity, cycle stability, and rate performance.

Description

Technical Field

[0001] This invention relates to the field of battery materials technology, and in particular to a multi-element doped ultra-high nickel cathode material, its preparation method, and its application. Background Technology

[0002] With the rapid development of solid-state battery technology, high-nickel layered oxide cathode materials (Ni≥85%) have become core candidate materials for next-generation high-energy-density solid-state batteries due to their high specific capacity and relatively low cost. However, with the increase of nickel content, the intrinsic stability problem of the material becomes increasingly prominent, mainly manifested in Li... ＋ -Ni 2＋ Severe mixing, lattice oxygen precipitation, intense interfacial side reactions, and microcrack propagation during cycling are among the problems.

[0003] To address the aforementioned issues, existing technologies generally employ elemental doping, typically selecting multiple elements in combination to enhance material stability at multiple scales—from the bulk lattice and particle interior to the solid-solid interface—thus meeting the application requirements of high-energy-density solid-state batteries. However, despite significant progress in existing multi-element doping technologies, the following key problems remain: ① Ambiguous functional positioning of doping elements: Existing technologies often simply pursue a large variety of elements without functionalizing them based on their electronic structure, ionic radius, redox activity, and other characteristics, resulting in limited performance improvement. For example, the introduction of high-valence elements such as Mo, Nb, Zr, and W may produce electron delocalization effects, but current technologies have not adequately explored this; ② Insufficient consideration of lattice compatibility: Multi-element co-doping may lead to the accumulation of lattice distortion. If the synergistic and compensatory effects between elements are not considered, it may instead cause lattice stress concentration, accelerating structural degradation; ③ Single selection of doping sites: Most multi-element doping only targets transition metal sites (3b sites), with insufficient attention paid to the regulation of lithium sites (3a sites). Studies have shown that lithium doping can expand the Li... ＋ Diffusion channels play a crucial role in improving rate performance; ④ Complex preparation process: Uniform multi-element doping requires high process standards. Traditional solid-state methods easily lead to uneven element distribution, while co-precipitation methods have stringent requirements for reaction condition control, making it difficult to balance doping uniformity and production efficiency. For example, CN117059795A discloses a high-entropy alloy modified high-nickel cobalt-free cathode material. By performing multi-element doping on the entire material, the structural stability is improved. However, this technology uses the same doping scheme for all sites and fails to design for the differentiated needs of different crystallographic positions, resulting in Li ＋Limited improvement in migration rate. CN116632186A proposed a gradient nickel-based cathode material with decreasing entropy from the outside to the inside, which only performs high-entropy doping on the outermost shell, thus improving cycle life to some extent. However, due to the lack of full-structure high entropy and the unoptimized element selection, the discharge specific capacity is low (191.2 mAh / g at 0.1C), making it difficult to meet the requirements for high energy density.

[0004] Therefore, how to provide an ultra-high nickel cathode material and its preparation method that can achieve synergistic optimization of bulk structure stability, interfacial chemical stability and kinetic performance is a technical problem that urgently needs to be solved. Summary of the Invention

[0005] To address the aforementioned technical problems, this invention provides a multi-element doped ultra-high nickel cathode material, its preparation method, and its applications. This invention uses Mo, Nb, Zr, and W as doping elements to achieve uniform multi-element doping throughout the entire particle from the core to the surface. Each element works synergistically to broaden the lattice and regulate electron delocalization: by widening the Li interlayer spacing, it enhances the Li... ＋ The diffusion coefficient is reduced by forming wide bandgap delocalized states in Li. ＋ The insertion / extraction barrier, combined with pinning to suppress oxygen evolution, together achieve the fast ion conductor effect, enabling multi-element doped ultra-high nickel cathode materials to have better discharge capacity, cycle stability and rate performance.

[0006] To achieve this objective, the present invention adopts the following technical solution:

[0007] In a first aspect, the present invention provides a multi-element doped ultra-high nickel cathode material, wherein the chemical formula of the multi-element doped ultra-high nickel cathode material is LiNi. x Mn y Mo a Nb b Zr c W d O2, where 0.85≤x≤0.90, for example 0.85, 0.86, 0.87, 0.88, 0.89, or 0.90, etc.; 0.03≤y≤0.08, for example 0.03, 0.04, 0.05, 0.06, 0.07, or 0.08, etc.; and 0.01≤a≤0.03, for example 0.01, 0.015, 0.02, 0.025, or 0.03, etc. , 0.01≤b≤0.02, for example 0.01, 0.012, 0.015, 0.018 or 0.02, etc.; 0.005≤c≤0.015, for example 0.005, 0.008, 0.01, 0.012 or 0.015, etc.; 0.005≤d≤0.015, for example 0.005, 0.008, 0.01, 0.012 or 0.015, etc.

[0008] This invention introduces four multi-element dopants—Mo, Nb, Zr, and W—along with Mn into the lattice of a nickel-rich ternary cathode material, achieving a synergistic improvement effect from single-element doping to multi-element functionalization. Specifically, Mn acts as a structural framework, providing a stable octahedral coordination environment and suppressing Jahn-Teller distortion; Mo enters the transition metal site (3b site), utilizing its Mo... 6＋ / Mo 4＋ The mixed valence state characteristic leads to the formation of electronically delocalized states in the crystal lattice, and the hybridization of d orbitals and O 2p orbitals forms a wide bandgap structure, significantly reducing the Li valence state. ＋ The insertion / extraction energy barrier increases electronic conductivity by 1-2 orders of magnitude; Nb enters the transition metal site (3b site), leveraging Nb... 5＋ With O 2－ The strong covalent bonding of Zr effectively pins lattice oxygen, suppressing the precipitation reaction of lattice oxygen under high delithiation states, thus reducing interfacial side reactions at the source. Due to its large ionic radius (0.72 Å), Zr partially enters the lithium sites (3a sites), widening the Li interlayer spacing from 2.6 Å to over 2.8 Å, providing a more spacious diffusion channel for lithium ions. + The diffusion coefficient is increased by 3-5 times, with some entering the transition metal site (3b site); W element enters the transition metal site (3b site), utilizing its W... 6＋ / W 4＋ The mixed valence state characteristic leads to the formation of electronically delocalized states in the crystal lattice, and the hybridization of d orbitals and O 2p orbitals forms a wide bandgap structure, significantly reducing the Li valence state. ＋ Zr can break the insertion / extraction energy barrier and form strong WO bonds, enhancing lattice rigidity, suppressing microcrack propagation during cycling, and improving structural mechanical stability. In summary, Zr widens the Li interlayer spacing and improves Li… ＋ The diffusion coefficient is reduced by the broad bandgap delocalization of Mo and W elements, which lowers the diffusion coefficient of Li. ＋ The insertion / extraction barrier is blocked, and Nb mainly acts as a pinning element to suppress oxygen evolution, thus achieving the fast ion conductor effect. This results in multi-element doped ultra-high nickel cathode materials having better discharge capacity, cycle stability and rate performance.

[0009] This invention combines structural stabilization and electronic structure modulation. Through multi-element doping, the electronic structure is controlled, reducing the material's free energy and suppressing phase transitions and elemental segregation. Multi-element d-orbital hybridization forms a continuous energy band, reducing polarization. Simultaneously, high-valence elements (Mo)... 6＋ 、Nb 5＋ and W 6＋ Both can form strong MO bonds, pinning lattice oxygen and inhibiting oxygen evolution reactions.

[0010] As a preferred technical solution of the present invention, the total molar amount of Mo, Nb, Zr and W accounts for 3.5 mol%-7.5 mol% of the total molar amount of transition metal elements, for example 3.5 mol%, 4 mol%, 4.5 mol%, 5 mol%, 5.5 mol%, 6 mol%, 6.5 mol%, 7 mol% or 7.5 mol%, etc.

[0011] This invention regulates the total molar amount of Mo, Nb, Zr, and W to 3.5 mol%-7.5 mol% of the total molar amount of transition metal elements. This maximizes the synergistic modification effect of multiple elements while ensuring the integrity of the layered crystal structure and the absence of impurity phase formation. If the total molar amount of Mo, Nb, Zr, and W is too low, it will lead to insufficient lattice stability, oxygen anchoring, and electronic regulation effects. If the total molar amount of Mo, Nb, Zr, and W is too high, it will cause severe lattice distortion, generate impurity phase structures, increase lithium-ion diffusion resistance, and reduce the reversible capacity of the material.

[0012] In a second aspect, the present invention also provides a method for preparing the multi-element doped ultra-high nickel cathode material according to the first aspect, the method comprising the following steps:

[0013] (1) Prepare nickel-manganese mixed salt solution, molybdenum-niobium mixed salt solution and zirconium-tungsten mixed salt solution according to the general chemical formula;

[0014] The nickel-manganese mixed salt solution and the precipitant-complexing agent mixture were added concurrently to the reaction substrate to carry out the first coprecipitation reaction, thereby obtaining the crystal nucleus slurry.

[0015] The nickel-manganese mixed salt solution, the molybdenum-niobium mixed salt solution, the zirconium-tungsten mixed salt solution, and the precipitant-complexing agent mixture are added in parallel to the crystal nucleation slurry to carry out a second coprecipitation reaction;

[0016] After the second coprecipitation reaction is completed, the feeding is stopped, and a crystallization reaction is carried out to obtain a multi-element doped precursor material;

[0017] (2) The lithium source and the multi-element doped precursor material described in step (1) are mixed evenly and sintered to obtain a multi-element doped ultra-high nickel cathode material.

[0018] The preparation method provided by this invention features good doping uniformity, high process controllability, and strong reproducibility, making it suitable for large-scale industrial production. From a cost perspective, all raw materials used are industrial-grade chemicals, requiring no expensive equipment and generating no solid or liquid waste, resulting in a significant cost advantage.

[0019] As a preferred technical solution of the present invention, the total metal ion concentration in the nickel-manganese mixed salt solution in step (1) is 1mol / L-3mol / L, for example, 1mol / L, 1.5mol / L, 2mol / L, 2.5mol / L or 3mol / L.

[0020] Preferably, the preparation method of the nickel-manganese mixed salt solution in step (1) includes: mixing nickel salt, manganese salt and deionized water evenly.

[0021] Preferably, the nickel salt includes at least one of nickel sulfate, nickel nitrate, nickel acetate, or nickel chloride.

[0022] Preferably, the manganese salt includes at least one of manganese sulfate, manganese nitrate, manganese acetate, or manganese chloride.

[0023] Preferably, the total metal ion concentration in the molybdenum-niobium mixed salt solution in step (1) is 0.08 mol / L-0.2 mol / L, such as 0.08 mol / L, 0.1 mol / L, 0.12 mol / L, 0.15 mol / L, 0.18 mol / L or 0.2 mol / L.

[0024] Preferably, the preparation method of the molybdenum-niobium mixed salt solution in step (1) includes: mixing molybdenum salt, niobium salt and ammonia solution evenly.

[0025] Preferably, the molybdenum salt includes at least one of ammonium molybdate, ammonium paratungstate, or ammonium dimolybdate.

[0026] Preferably, the niobium salt includes at least one of niobium ammonium oxalate hydrate, niobium pentachloride, or niobium oxalate hydrate.

[0027] Preferably, the pH of the ammonia solution is 8-10, such as 8, 8.5, 9, 9.5 or 10.

[0028] Preferably, the total metal ion concentration in the zirconium-tungsten mixed salt solution in step (1) is 0.01 mol / L-0.1 mol / L, such as 0.01 mol / L, 0.03 mol / L, 0.05 mol / L, 0.08 mol / L or 0.1 mol / L.

[0029] Preferably, the method for preparing the zirconium-tungsten mixed salt solution in step (1) includes: mixing zirconium salt, tungsten salt and deionized water evenly.

[0030] Preferably, the zirconium salt includes at least one of zirconium oxynitrate, zirconium tetrachloride, or zirconium acetate.

[0031] Preferably, the tungsten salt includes at least one of ammonium metatungstate, ammonium paratungstate, or sodium tungstate.

[0032] Preferably, the molar concentration of the precipitant in the precipitant-complexing agent mixture in step (1) is 1 mol / L-8 mol / L, such as 1 mol / L, 3 mol / L, 5 mol / L or 8 mol / L.

[0033] Preferably, the precipitant comprises sodium hydroxide.

[0034] Preferably, the molar concentration of the complexing agent in the precipitant-complexing agent mixture in step (1) is 0.1 mol / L-5 mol / L, such as 0.1 mol / L, 0.5 mol / L, 1 mol / L, 2 mol / L, 3 mol / L, 4 mol / L or 5 mol / L.

[0035] Preferably, the complexing agent comprises ammonia.

[0036] Preferably, the reaction substrate in step (1) comprises a mixed solution of pure water and ammonia.

[0037] Preferably, the pH of the reaction substrate in step (1) is 10-12, such as 10, 10.2, 10.5, 10.8, 11, 11.2, 11.5, 11.8 or 12.

[0038] As a preferred technical solution of the present invention, in step (1), the first coprecipitation reaction, the second coprecipitation reaction and the crystallization reaction are all carried out under an inert atmosphere.

[0039] Preferably, the inert atmosphere includes a nitrogen atmosphere.

[0040] Preferably, the feed rate of the nickel-manganese mixed salt solution in step (1) is 45L / h-55L / h, such as 45L / h, 48L / h, 50L / h, 52L / h or 55L / h.

[0041] Preferably, the pH of the first coprecipitation reaction in step (1) is 10.5-11.4.

[0042] Preferably, the temperature of the first coprecipitation reaction in step (1) is 40℃-60℃, such as 40℃, 45℃, 50℃, 55℃ or 60℃.

[0043] Preferably, the stirring rate of the first coprecipitation reaction in step (1) is 500 rpm to 900 rpm, for example, 500 rpm, 600 rpm, 700 rpm, 800 rpm or 900 rpm.

[0044] Preferably, the reaction time of the first coprecipitation reaction in step (1) is 1h-4h, for example 1h, 2h, 3h or 4h.

[0045] As a preferred technical solution of the present invention, the feed rate of the molybdenum-niobium mixed salt solution in step (1) is linearly increased from 0 to a preset feed rate of the molybdenum-niobium mixed salt solution.

[0046] Preferably, the preset feed rate of the molybdenum-niobium mixed salt solution is 30L / h-50L / h, such as 30L / h, 35L / h, 40L / h, 45L / h or 50L / h.

[0047] Preferably, the time for the feed rate of the molybdenum-niobium mixed salt solution to increase linearly from 0 to the preset feed rate is 3h-5h, such as 3h, 4h or 5h.

[0048] Preferably, the feed rate of the zirconium-tungsten mixed salt solution in step (1) is linearly increased from 0 to a preset feed rate of the zirconium-tungsten mixed salt solution.

[0049] Preferably, the preset feed rate of the zirconium-tungsten mixed salt solution is 25L / h-40L / h, such as 25L / h, 30L / h, 35L / h or 40L / h.

[0050] Preferably, the time for the feed rate of the zirconium-tungsten mixed salt solution to increase linearly from 0 to the preset feed rate is 3h-6h, such as 3h, 4h, 5h or 6h.

[0051] In this invention, the feed rate of the molybdenum-niobium mixed salt solution is linearly increased from 0 to a preset feed rate, and the feed rate of the zirconium-tungsten mixed salt solution is linearly increased from 0 to a preset feed rate. A gradient co-precipitation method is adopted. No doping elements are added in the initial nucleation stage (first co-precipitation reaction stage). In the doping stage (second co-precipitation reaction stage), the feed rates of the mixed salt molybdenum-niobium mixed salt solution and the zirconium-tungsten mixed salt solution corresponding to the doping elements Mo, Nb, Zr, and W are linearly increased from 0 to the preset feed rate. The linear increase in the feed rate can avoid the compositional segregation and lattice distortion caused by the simultaneous nucleation of multiple elements in the early stage of co-precipitation, ensure the controllability of the entire co-precipitation stage, and ensure the structure of the obtained cathode material and the uniformity of element doping.

[0052] As a preferred technical solution of the present invention, the pH of the second coprecipitation reaction in step (1) is 10.5-11.4.

[0053] Preferably, the temperature of the second coprecipitation reaction in step (1) is 40℃-60℃, such as 40℃, 45℃, 50℃, 55℃ or 60℃.

[0054] Preferably, the stirring rate of the second coprecipitation reaction in step (1) is 200 rpm to 700 rpm, for example, 200 rpm, 300 rpm, 400 rpm, 500 rpm, 600 rpm or 700 rpm.

[0055] Preferably, the reaction time of the second coprecipitation reaction in step (1) is 10h-18h, for example, 10h, 12h, 15h or 18h.

[0056] Preferably, the pH of the crystallization reaction in step (1) is 10.5-12.5, such as 10.5, 10.8, 11, 11.2, 11.5, 11.8, 12, 12.2 or 12.5.

[0057] Preferably, the temperature of the crystallization reaction in step (1) is 50℃-70℃, such as 50℃, 55℃, 60℃, 65℃ or 70℃.

[0058] Preferably, the stirring rate of the crystallization reaction in step (1) is 200 rpm to 700 rpm, for example, 200 rpm, 300 rpm, 400 rpm, 500 rpm, 600 rpm or 700 rpm.

[0059] Preferably, the reaction time of the crystallization reaction in step (1) is 4h-8h, for example 4h, 5h, 6h, 7h or 8h.

[0060] Preferably, after the crystallization reaction in step (1) is completed, the steps of solid-liquid separation, washing and drying are also included.

[0061] It should be noted that this invention does not impose specific requirements or limitations on the solid-liquid separation method. Commonly used solid-liquid separation methods in the art are applicable to this invention, such as filtration or centrifugation. Similarly, this invention does not impose specific requirements or limitations on the drying method, corresponding temperature, and time. Commonly used methods, corresponding temperatures, and times in the art are applicable to this invention, as long as complete drying of the product can be achieved.

[0062] As a preferred technical solution of the present invention, the lithium source in step (2) includes at least one of LiOH·H2O, LiOH or lithium carbonate.

[0063] Preferably, in step (2), the molar ratio between the Li element in the lithium source and the total transition metal elements in the multi-element doped precursor material in step (1) is (1-1.05):1, for example, 1:1, 1.01:1, 1.02:1, 1.03:1, 1.04:1 or 1.05:1, etc.

[0064] Preferably, the raw materials mixed in step (2) also include a flux.

[0065] The addition of flux in this invention promotes the lithiation reaction. NH4Cl decomposes upon heating to produce HCl gas, which can react with residual LiOH and Li2CO3 on the precursor surface, lowering the lithiation energy barrier and enabling Li... ＋ First, it makes it easier to enter the crystal lattice; second, it lowers the sintering temperature, as the flux can form a trace liquid phase, promoting element diffusion and facilitating uniform solid solution of elements at relatively low temperatures; third, it improves the morphology of single crystals, assists in the growth of single crystal particles, and makes the particles denser and the crystal orientation better.

[0066] Preferably, the flux includes NH4Cl.

[0067] Preferably, the amount of flux added is 0.1wt%-1wt% of the mass of the multi-element doped precursor material, such as 0.1wt%, 0.3wt%, 0.5wt%, 0.8wt% or 1wt%.

[0068] As a preferred technical solution of the present invention, the sintering in step (2) includes a first-stage sintering, a second-stage sintering, a third-stage sintering, a fourth-stage sintering and a cooling stage performed sequentially.

[0069] Preferably, the heating rate of the sintering section is 1℃ / min-5℃ / min, for example, 1℃ / min, 2℃ / min, 3℃ / min, 4℃ / min or 5℃ / min.

[0070] Preferably, the holding temperature of the first sintering stage is 350℃-530℃, such as 350℃, 380℃, 400℃, 420℃, 450℃, 480℃, 500℃ or 530℃.

[0071] Preferably, the holding time for the first sintering stage is 3h-7h, such as 3h, 4h, 5h, 6h or 7h.

[0072] Preferably, the heating rate of the two-stage sintering is 0.1℃ / min-0.8℃ / min, for example, 0.1℃ / min, 0.2℃ / min, 0.3℃ / min, 0.4℃ / min, 0.5℃ / min, 0.6℃ / min, 0.7℃ / min or 0.8℃ / min, etc.

[0073] Preferably, the holding temperature for the two-stage sintering is 550℃-730℃, such as 550℃, 580℃, 600℃, 620℃, 650℃, 680℃, 700℃ or 730℃.

[0074] Preferably, the holding time for the two-stage sintering is 8h-12h, such as 8h, 9h, 10h, 11h or 12h.

[0075] Preferably, the heating rate of the three-stage sintering is 1℃ / min-5℃ / min, for example, 1℃ / min, 2℃ / min, 3℃ / min, 4℃ / min or 5℃ / min.

[0076] Preferably, the holding temperature for the three-stage sintering is 750℃-850℃, such as 750℃, 780℃, 800℃, 820℃ or 850℃.

[0077] Preferably, the holding time for the three-stage sintering is 12h-15h, such as 12h, 13h, 14h or 15h.

[0078] Preferably, the heating rate of the four-stage sintering is 2℃ / min-10℃ / min, for example, 2℃ / min, 3℃ / min, 4℃ / min, 5℃ / min, 6℃ / min, 7℃ / min, 8℃ / min, 9℃ / min or 10℃ / min.

[0079] Preferably, the holding temperature for the four-stage sintering is 850℃-1000℃, such as 850℃, 880℃, 900℃, 920℃, 950℃, 980℃ or 1000℃.

[0080] In this invention, when the holding temperature for three-stage sintering is 850°C, the holding temperature for four-stage sintering is >850°C.

[0081] Preferably, the holding time for the four-stage sintering is 1-3 hours, such as 1 hour, 2 hours or 3 hours.

[0082] Preferably, the sintering gas used in the first-stage sintering, the second-stage sintering, and the third-stage sintering each independently includes oxygen.

[0083] Preferably, the sintering gas used in the four-stage sintering includes argon.

[0084] Preferably, the cooling rate of the cooling section is 0.1℃ / min-0.8℃ / min, for example, 0.1℃ / min, 0.2℃ / min, 0.3℃ / min, 0.4℃ / min, 0.5℃ / min, 0.6℃ / min, 0.7℃ / min or 0.8℃ / min, etc.

[0085] Preferably, the cooling section cools the temperature from the holding temperature of the four sintering sections to 300℃-500℃, such as 300℃, 320℃, 350℃, 380℃, 400℃, 420℃, 450℃, 480℃ or 500℃.

[0086] This invention employs a variable temperature and variable atmosphere multi-stage sintering process. The first stage of sintering achieves preliminary lithiation, forming a layered structural framework. The second stage of sintering uses an extremely slow heating rate to ensure sufficient diffusion of multiple elements, forming a uniform solid solution. The third stage of sintering promotes the growth of single crystal particles and optimizes crystal orientation. The fourth stage of sintering induces the formation of oxygen vacancies through an oxygen-deficient environment, modulates the electronic structure, and further enhances the electron delocalization effect. The cooling stage uses extremely slow annealing to release lattice stress, thereby stabilizing the overall structure of the material.

[0087] Based on multi-element doped precursor materials with gradient doping of doped elements, this invention utilizes two-stage and three-stage sintering processes, extremely slow heating rates, and long holding times to allow the doping elements in the multi-element doped precursor materials to fully diffuse into the particle interior. This achieves uniform multi-element doping throughout the entire particle from the core to the surface, while also increasing the structural stability of the material.

[0088] Thirdly, the present invention also provides a solid-state battery, the solid-state battery comprising the multi-element doped ultra-high nickel cathode material as described in the first aspect, or the multi-element doped ultra-high nickel cathode material prepared by the preparation method described in the second aspect.

[0089] Compared with the prior art, the present invention has at least the following beneficial effects:

[0090] 1) This invention uses four elements—Mo, Nb, Zr, and W—as doping elements to achieve uniform multi-element doping throughout the entire particle from the core to the surface. Each element works synergistically to broaden the lattice and regulate electron delocalization: by broadening the Li interlayer spacing, it enhances the Li… ＋ The diffusion coefficient is reduced by forming wide bandgap delocalized states in Li. ＋ The insertion / extraction barrier, combined with pinning to suppress oxygen evolution, together achieve the fast ion conductor effect, enabling multi-element doped ultra-high nickel cathode materials to have better discharge capacity, cycle stability and rate performance.

[0091] 2) The preparation method provided by this invention features good doping uniformity, high process controllability, and strong reproducibility, making it suitable for large-scale industrial production. From a cost perspective, all raw materials used are industrial-grade chemicals, requiring no expensive equipment and generating no solid or liquid waste, resulting in a significant cost advantage. Detailed Implementation

[0092] To facilitate understanding of the present invention, the following embodiments are provided. Those skilled in the art should understand that these embodiments are merely illustrative and should not be construed as limiting the scope of the invention.

[0093] The scope of this invention can be defined by lower and upper limits. The selected lower and upper limits define the boundaries of a specific range. The range defined in this way can be defined by the inclusion or exclusion of endpoints. Any endpoint can be independently selected for inclusion or exclusion, and all lower and upper limits can be arbitrarily combined to form new ranges. That is, any lower limit can be combined with any upper limit to form an effective range. For example, if the ranges of 60~120 and 80~110 are listed for specific parameters, it should be understood that the ranges of 60~110 and 80~120 also fall within the scope of this invention. In addition, if the minimum range values ​​1 and 2 are listed, and the maximum range values ​​3, 4 and 5 are also listed, then all ranges of 1~3, 1~4, 1~5, 2~3, 2~4 and 2~5 fall within the scope of this invention. In this invention, the numerical range "a~b" represents a shortened representation of any combination of real numbers between a and b, where a and b are both real numbers. For example, the numerical range "0~5" means that all real numbers between 0 and 5 have been fully listed in this document, and "0~5" is only a shortened representation of this set of numerical combinations. When a parameter is expressed as an integer ≥2, it is equivalent to listing positive integers that meet the requirements, such as 2, 3, 4, 5, 6, 7, 8, 9, 10, etc. When a parameter is expressed as an integer selected from "2~10", it is equivalent to listing any integer among 2, 3, 4, 5, 6, 7, 8, 9, and 10.

[0094] In this invention, "a combination of at least two" refers to a quantity greater than or equal to 2 unless otherwise specified. For example, "any one or a combination of at least two" means that any one of the listed items can be selected, or a combination of at least two of the listed items formed in a manner that does not conflict and enables the implementation of this invention. In this invention, unless otherwise specified, the features or solutions corresponding to "and / or" cover any one of two or more related listed items, as well as any and all combinations of the related listed items. The arbitrary and all combinations include any two related listed items, any more related listed items, or a combination of all related listed items. For example, "A and / or B" means a set consisting of A, B, and combinations of A and B, where "containing A and / or B" can be understood, depending on the context of the statement, as containing A, containing B, or simultaneously containing both A and B. In this invention, "optional" means that the corresponding feature, component, step or solution is not necessary, that is, it is selected from either "with" or "without". If there are multiple "optional" limitations in a technical solution, unless otherwise specified and there is no technical conflict or mutual constraint, each "optional" limitation is independent and does not affect the others.

[0095] In this invention, technical features or solutions described using open-ended terms such as "comprising" or "including" do not exclude additional non-conflicting elements beyond the listed elements unless otherwise specified. They are considered to disclose both closed-ended features or solutions consisting solely of the listed elements and open-ended features or solutions that may include additional non-conflicting elements beyond the listed elements. For example, if A includes a1, a2, and a3, unless otherwise specified, this means that A can consist only of a1, a2, and a3, or it can include other non-conflicting elements based on a1, a2, and a3. This corresponds to the disclosure of technical solutions such as "A consists of a1, a2, and a3," "A is selected from a1, a2, and a3," and "A not only includes a1, a2, and a3, but may also include other non-conflicting elements." All embodiments and optional embodiments of this invention, unless otherwise specified and without technical conflict, can be combined to form new technical solutions, and such combinations fall within the scope of this invention. The term "embodiment" as used in this invention means that a specific feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment or implementation of the invention. The appearance of this phrase in various locations throughout the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment mutually exclusive with other embodiments. Those skilled in the art will understand, explicitly and implicitly, that the embodiments described in this invention can be combined with other embodiments that do not conflict with the technology. The ordinal numbers "first," "second," "third," and "fourth," etc., used in the expressions "first aspect," "second aspect," "third aspect," and "fourth aspect" in this invention are for descriptive purposes only and should not be construed as indicating or implying relative importance or quantity, nor should they be construed as implicitly specifying the importance or quantity of the indicated technical features. They serve only as a non-exhaustive enumeration and do not constitute a closed limitation on quantity.

[0096] In this invention, the order in which the steps are written in the methods described in each embodiment does not imply a strict execution order. The actual execution order of each step should be determined based on its function and possible internal logic. Unless otherwise specified, all steps of this invention can be executed in the order they are written, or in any order without technical conflict. For example, if the method includes steps (a) and (b), it means that the method may include steps (a) and (b) executed sequentially, or it may include steps (b) and (a) executed sequentially. If the method also includes step (c), then step (c) can be added to the method in any order without conflict, including but not limited to the execution order of steps (a), (b), and (c), steps (a), (c), and (b), steps (c), (a), and (b), etc.

[0097] Example 1

[0098] This embodiment provides a multi-element doped ultra-high nickel cathode material, the chemical formula of which is LiNi.0.88 Mn 0.06 Mo 0.02 Nb 0.015 Zr 0.01 W 0.015 The total molar amount of O2, Mo, Nb, Zr and W accounts for 6 mol of the total molar amount of transition metal elements.

[0099] This invention provides a method for preparing the multi-element doped ultra-high nickel cathode material, the method comprising the following steps:

[0100] (1) Based on the chemical formula, NiSO4·6H2O and MnSO4·H2O were dissolved in deionized water at a molar ratio of Ni:Mn=0.88:0.06 to obtain a nickel-manganese mixed salt solution with a total metal ion concentration of 1.5 mol / L. (NH4)6Mo7O was then dissolved in water at a molar ratio of Mo:Nb=0.02:0.015. 24 ·4H2O and C4H4NNbO9·xH2O were dissolved in dilute ammonia water (pH=9) to obtain a molybdenum-niobium mixed salt solution with a total metal ion concentration of 0.1 mol / L. ZrO(NO3)2·2H2O and (NH4)6H2W were then added according to a molar ratio of Zr:W = 0.01:0.015. 12 O 40 ·xH2O was dissolved in deionized water to obtain a zirconium-tungsten mixed salt solution with a total metal ion concentration of 0.05 mol / L. A precipitant-complexing agent mixture containing 4 mol / L NaOH and 2 mol / L NH3·H2O was prepared (solvent: deionized water).

[0101] Under a nitrogen atmosphere, a nickel-manganese mixed salt solution and a precipitant-complexing agent mixture were added in parallel to a reaction substrate (pure water + ammonia) with a pH of 11 to carry out the first coprecipitation reaction. The feed rate of the nickel-manganese mixed salt solution was 50 L / h. The pH of the first coprecipitation reaction was controlled at 11.2 ± 0.1 by the precipitant-complexing agent mixture. The reaction temperature was 55℃, the stirring speed was 700 rpm, and the reaction time was 2 h to obtain a crystal nucleus slurry.

[0102] A nickel-manganese mixed salt solution, a molybdenum-niobium mixed salt solution, a zirconium-tungsten mixed salt solution, and a precipitant-complexing agent mixture were added in parallel to the above-mentioned crystal nucleation slurry for a second coprecipitation reaction. The feed rate of the nickel-manganese mixed salt solution was 50 L / h, the feed rate of the molybdenum-niobium mixed salt solution was linearly increased from 0 to 40 L / h over a period of 4 h, and the feed rate of the zirconium-tungsten mixed salt solution was linearly increased from 0 to 32 L / h over a period of 4 h. The pH of the first coprecipitation reaction was controlled at 11.2 ± 0.1 by the precipitant-complexing agent mixture, the reaction temperature was 55 °C, the stirring speed was 500 rpm, and the reaction time was 12 h.

[0103] After the second coprecipitation reaction was completed, the solution feed was stopped, the temperature of the reaction system was raised to 65°C, an appropriate amount of ammonia was added to adjust the pH to 11.5, and the crystallization reaction was continued at 500 rpm for 6 hours. After the reaction was completed, the precipitate was centrifuged and washed until neutral, and dried at 120°C for 12 hours to obtain the multi-element doped precursor material.

[0104] (2) LiOH·H2O and multi-element doped precursor materials were mixed evenly at a molar ratio of Li:(Ni+Mn+Mo+Nb+Zr+W)=1.05:1. 0.3wt% of NH4Cl was added to the multi-element doped precursor materials and mixed evenly before sintering. First, the temperature was raised to 450℃ at 1℃ / min and held for 5h under an oxygen atmosphere for the first stage of sintering. Then, the temperature was raised to 650℃ at 0.5℃ / min and held for 10h under an oxygen atmosphere for the second stage of sintering. Then, the temperature was raised to 800℃ at 1℃ / min and held for 15h under an oxygen atmosphere for the third stage of sintering. Then, the temperature was raised to 850℃ at 2℃ / min and held for 3h under an argon atmosphere for the fourth stage of sintering. Then, the temperature was lowered to 400℃ at 0.2℃ / min and then naturally cooled to obtain the multi-element doped ultra-high nickel cathode material.

[0105] Example 2

[0106] This embodiment provides a multi-element doped ultra-high nickel cathode material, the chemical formula of which is LiNi. 0.87 Mn 0.06 Mo 0.03 Nb 0.015 Zr 0.01 W 0.015 The total molar amount of O2, Mo, Nb, Zr and W accounts for 7 mol of the total molar amount of transition metal elements.

[0107] This invention provides a method for preparing the multi-element doped ultra-high nickel cathode material. The difference between this method and Example 1 is that the molar ratio between the elements in the nickel-manganese mixed salt solution, the molybdenum-niobium mixed salt solution, and the zirconium-tungsten mixed salt solution is adjusted according to the chemical formula. The remaining preparation methods and parameters are consistent with those in Example 1.

[0108] Example 3

[0109] This embodiment provides a multi-element doped ultra-high nickel cathode material, the chemical formula of which is LiNi. 0.86 Mn 0.07 Mo 0.03 Nb 0.015 Zr 0.01 W 0.015 The total molar amount of O2, Mo, Nb, Zr and W accounts for 7 mol of the total molar amount of transition metal elements.

[0110] This invention provides a method for preparing the multi-element doped ultra-high nickel cathode material. The difference between this method and Example 1 is that the molar ratio between the elements in the nickel-manganese mixed salt solution, the molybdenum-niobium mixed salt solution, and the zirconium-tungsten mixed salt solution is adjusted according to the chemical formula. The remaining preparation methods and parameters are consistent with those in Example 1.

[0111] Example 4

[0112] This embodiment provides a multi-element doped ultra-high nickel cathode material, the chemical formula of which is LiNi. 0.85 Mn 0.08 Mo 0.03 Nb 0.015 Zr 0.01 W 0.015 The total molar amount of O2, Mo, Nb, Zr and W accounts for 7 mol of the total molar amount of transition metal elements.

[0113] This invention provides a method for preparing the multi-element doped ultra-high nickel cathode material. The difference between this method and Example 1 is that the molar ratio between the elements in the nickel-manganese mixed salt solution, the molybdenum-niobium mixed salt solution, and the zirconium-tungsten mixed salt solution is adjusted according to the chemical formula. The remaining preparation methods and parameters are consistent with those in Example 1.

[0114] Example 5

[0115] This embodiment provides a multi-element doped ultra-high nickel cathode material, the chemical formula of which is LiNi. 0.885 Mn 0.08 Mo 0.01 Nb 0.01 Zr 0.01 W 0.005 The total molar amount of O2, Mo, Nb, Zr and W accounts for 3.5 mol of the total molar amount of transition metal elements.

[0116] This invention provides a method for preparing the multi-element doped ultra-high nickel cathode material, the method comprising the following steps:

[0117] (1) According to the chemical formula, NiSO4·6H2O and MnSO4·H2O are dissolved in deionized water at a molar ratio of Ni:Mn=0.885:0.08 to obtain a nickel-manganese mixed salt solution with a total metal ion concentration of 1 mol / L. (NH4)6Mo7O is then dissolved in water at a molar ratio of Mo:Nb=0.01:0.01. 24·4H2O and C4H4NNbO9·xH2O were dissolved in dilute ammonia water (pH=9) to obtain a molybdenum-niobium mixed salt solution with a total metal ion concentration of 0.08 mol / L. ZrO(NO3)2·2H2O and (NH4)6H2W were then added according to a molar ratio of Zr:W = 0.01:0.005. 12 O 40 ·xH2O was dissolved in deionized water to obtain a zirconium-tungsten mixed salt solution with a total metal ion concentration of 0.1 mol / L. A precipitant-complexing agent mixture containing 4 mol / L NaOH and 2 mol / L NH3·H2O was prepared (solvent: deionized water).

[0118] Under a nitrogen atmosphere, a nickel-manganese mixed salt solution and a precipitant-complexing agent mixture were added in parallel to a reaction substrate (pure water + ammonia) with a pH of 10 to carry out the first coprecipitation reaction. The feed rate of the nickel-manganese mixed salt solution was 45 L / h. The pH of the first coprecipitation reaction was controlled at 11.3 ± 0.1 by the precipitant-complexing agent mixture. The reaction temperature was 40℃, the stirring speed was 900 rpm, and the reaction time was 1 h to obtain a crystal nucleus slurry.

[0119] A nickel-manganese mixed salt solution, a molybdenum-niobium mixed salt solution, a zirconium-tungsten mixed salt solution, and a precipitant-complexing agent mixture were added in parallel to the above-mentioned crystal nucleation slurry for a second coprecipitation reaction. The feed rate of the nickel-manganese mixed salt solution was 45 L / h, the feed rate of the molybdenum-niobium mixed salt solution was linearly increased from 0 to 30 L / h over a period of 3 h, and the feed rate of the zirconium-tungsten mixed salt solution was linearly increased from 0 to 40 L / h over a period of 6 h. The pH of the first coprecipitation reaction was controlled at 11.3 ± 0.1 by the precipitant-complexing agent mixture, the reaction temperature was 40 °C, the stirring speed was 700 rpm, and the reaction time was 10 h.

[0120] After the second coprecipitation reaction was completed, the solution feed was stopped, the temperature of the reaction system was raised to 50°C, an appropriate amount of ammonia was added to adjust the pH to 10.5, and the crystallization reaction was continued at 700 rpm for 6 hours. After the reaction was completed, the precipitate was centrifuged and washed until neutral, and dried at 120°C for 12 hours to obtain the multi-element doped precursor material.

[0121] (2) LiOH·H2O and multi-element doped precursor materials were mixed evenly at a molar ratio of Li:(Ni+Mn+Mo+Nb+Zr+W)=1.05:1. 0.1wt% of NH4Cl was added to the multi-element doped precursor materials and mixed evenly before sintering. First, the temperature was raised to 530℃ at 2℃ / min and held for 3h under an oxygen atmosphere for the first stage of sintering. Then, the temperature was raised to 550℃ at 0.1℃ / min and held for 12h under an oxygen atmosphere for the second stage of sintering. Then, the temperature was raised to 850℃ at 2℃ / min and held for 12h under an oxygen atmosphere for the third stage of sintering. Then, the temperature was raised to 900℃ at 5℃ / min and held for 1h under an argon atmosphere for the fourth stage of sintering. Then, the temperature was lowered to 500℃ at 0.1℃ / min and then naturally cooled to obtain the multi-element doped ultra-high nickel cathode material.

[0122] Example 6

[0123] This embodiment provides a multi-element doped ultra-high nickel cathode material, the chemical formula of which is LiNi. 0.895 Mn 0.03 Mo 0.03 Nb 0.02 Zr 0.015 W 0.01 The total molar amount of O2, Mo, Nb, Zr and W accounts for 7.5 mol of the total molar amount of transition metal elements.

[0124] This invention provides a method for preparing the multi-element doped ultra-high nickel cathode material, the method comprising the following steps:

[0125] (1) According to the chemical formula, NiSO4·6H2O and MnSO4·H2O were dissolved in deionized water at a molar ratio of Ni:Mn=0.895:0.03 to obtain a nickel-manganese mixed salt solution with a total metal ion concentration of 3 mol / L. (NH4)6Mo7O was then dissolved in water at a molar ratio of Mo:Nb=0.03:0.02. 24 ·4H2O and C4H4NNbO9·xH2O were dissolved in dilute ammonia water (pH=9) to obtain a molybdenum-niobium mixed salt solution with a total metal ion concentration of 0.2 mol / L. ZrO(NO3)2·2H2O and (NH4)6H2W were then added according to a molar ratio of Zr:W = 0.015:0.01. 12 O 40 ·xH2O was dissolved in deionized water to obtain a zirconium-tungsten mixed salt solution with a total metal ion concentration of 0.01 mol / L. A precipitant-complexing agent mixture containing 4 mol / L NaOH and 2 mol / L NH3·H2O was prepared (solvent: deionized water).

[0126] Under a nitrogen atmosphere, a nickel-manganese mixed salt solution and a precipitant-complexing agent mixture were added in parallel to a reaction substrate (pure water + ammonia) at pH 12 to carry out the first coprecipitation reaction. The feed rate of the nickel-manganese mixed salt solution was 55 L / h. The pH of the first coprecipitation reaction was controlled at 11.0 ± 0.1 by the precipitant-complexing agent mixture. The reaction temperature was 60℃, the stirring speed was 500 rpm, and the reaction time was 4 h to obtain a crystal nucleus slurry.

[0127] A nickel-manganese mixed salt solution, a molybdenum-niobium mixed salt solution, a zirconium-tungsten mixed salt solution, and a precipitant-complexing agent mixture were added in parallel to the above-mentioned crystal nucleation slurry for a second coprecipitation reaction. The feed rate of the nickel-manganese mixed salt solution was 55 L / h, the feed rate of the molybdenum-niobium mixed salt solution was linearly increased from 0 to 50 L / h over a period of 5 h, and the feed rate of the zirconium-tungsten mixed salt solution was linearly increased from 0 to 25 L / h over a period of 3 h. The pH of the first coprecipitation reaction was controlled at 11.0 ± 0.1 by the precipitant-complexing agent mixture, the reaction temperature was 60 °C, the stirring speed was 200 rpm, and the reaction time was 18 h.

[0128] After the second coprecipitation reaction was completed, the solution feed was stopped, the temperature of the reaction system was raised to 70°C, an appropriate amount of ammonia was added to adjust the pH to 12.5, and the crystallization reaction was continued at 200 rpm for 8 hours. After the reaction was completed, the precipitate was centrifuged and washed until neutral, and dried at 120°C for 12 hours to obtain the multi-element doped precursor material.

[0129] (2) LiOH·H2O and multi-element doped precursor materials were mixed evenly at a molar ratio of Li:(Ni+Mn+Mo+Nb+Zr+W)=1.05:1. 1 wt% of NH4Cl was added to the multi-element doped precursor materials and mixed evenly before sintering. First, the temperature was raised to 350℃ at 5℃ / min and held for 7h under an oxygen atmosphere for the first stage of sintering. Then, the temperature was raised to 730℃ at 0.8℃ / min and held for 8h under an oxygen atmosphere for the second stage of sintering. Then, the temperature was raised to 750℃ at 5℃ / min and held for 15h under an oxygen atmosphere for the third stage of sintering. Then, the temperature was raised to 1000℃ at 5℃ / min and held for 3h under an argon atmosphere for the fourth stage of sintering. Then, the temperature was lowered to 300℃ at 0.8℃ / min and then naturally cooled to obtain the multi-element doped ultra-high nickel cathode material.

[0130] Example 7

[0131] This embodiment provides a multi-element doped ultra-high nickel cathode material, the chemical formula of which is consistent with that of Embodiment 1.

[0132] This invention provides a method for preparing the multi-element doped ultra-high nickel cathode material. The difference between this method and Example 1 is that in step (1), a one-step co-precipitation reaction is directly adopted. Under a nitrogen atmosphere, a nickel-manganese mixed salt solution, a molybdenum-niobium mixed salt solution, a zirconium-tungsten mixed salt solution, and a precipitant-complexing agent mixture are added in parallel to a reaction base solution (pure water + ammonia water) with a pH of 11 for co-precipitation reaction. The feed rate of the nickel-manganese mixed salt solution is 50 L / h, the feed rate of the molybdenum-niobium mixed salt solution is 40 L / h, and the feed rate of the zirconium-tungsten mixed salt solution is 32 L / h. The pH of the co-precipitation reaction is controlled to be 11.0 ± 0.2 by the precipitant-complexing agent mixture, the reaction temperature is 55℃, the stirring speed is 450 pm, and the reaction time is 12 h. After the co-precipitation reaction is completed, the solution feed is stopped, and a crystallization reaction is carried out to obtain the multi-element doped precursor material. The remaining preparation methods and parameters are consistent with those of Example 1.

[0133] Example 8

[0134] This embodiment provides a multi-element doped ultra-high nickel cathode material, the chemical formula of which is consistent with that of Embodiment 1.

[0135] This invention provides a method for preparing the multi-element doped ultra-high nickel cathode material. The difference between this method and Example 1 is that the four-stage sintering process is still carried out in an oxygen atmosphere, with the temperature increased to 850°C at a rate of 2°C / min and held for 3 hours. The other preparation methods and parameters are consistent with those in Example 1.

[0136] Example 9

[0137] This embodiment provides a multi-element doped ultra-high nickel cathode material, the chemical formula of which is LiNi. 0.90 Mn 0.07 Mo 0.01 Nb 0.01 Zr 0.005 W 0.005 The total molar amount of O2, Mo, Nb, Zr and W accounts for 3 mol of the total molar amount of transition metal elements.

[0138] This invention provides a method for preparing the multi-element doped ultra-high nickel cathode material. The difference between this method and Example 1 is that the molar ratio between the elements in the nickel-manganese mixed salt solution, the molybdenum-niobium mixed salt solution, and the zirconium-tungsten mixed salt solution is adjusted according to the chemical formula. The remaining preparation methods and parameters are consistent with those in Example 1.

[0139] Example 10

[0140] This embodiment provides a multi-element doped ultra-high nickel cathode material, the chemical formula of which is LiNi.0.85 Mn 0.07 Mo 0.03 Nb 0.02 Zr 0.015 W 0.015 The total molar amount of O2, Mo, Nb, Zr and W accounts for 8 mol of the total molar amount of transition metal elements.

[0141] This invention provides a method for preparing the multi-element doped ultra-high nickel cathode material. The difference between this method and Example 1 is that the molar ratio between the elements in the nickel-manganese mixed salt solution, the molybdenum-niobium mixed salt solution, and the zirconium-tungsten mixed salt solution is adjusted according to the chemical formula. The remaining preparation methods and parameters are consistent with those in Example 1.

[0142] Comparative Example 1

[0143] This comparative example provides an ultra-high nickel cathode material with the chemical formula LiNi. 0.95 Mn 0.05 O2.

[0144] This comparative example provides a method for preparing the ultra-high nickel cathode material, the method comprising the following steps:

[0145] (1) According to the chemical formula, NiSO4·6H2O and MnSO4·H2O were dissolved in deionized water at a molar ratio of Ni:Mn=0.95:0.05 to obtain a mixed salt solution of nickel, cobalt and manganese with a total metal ion concentration of 2mol / L. A precipitant-complexing agent mixture containing 4mol / L NaOH and 2mol / L NH3·H2O (solvent: deionized water) was prepared.

[0146] Under a nitrogen atmosphere, a nickel-manganese mixed salt solution and a precipitant-complexing agent mixture were co-added to a reaction substrate (pure water + ammonia) with a pH of 11 for co-precipitation. The feed rate of the nickel-manganese mixed salt solution was 50 L / h. The pH of the co-precipitation reaction was controlled at 11.0 ± 0.2 by the precipitant-complexing agent mixture. The reaction temperature was 55℃, the stirring speed was 450 rpm, and the reaction time was 12 h to obtain an ultra-high nickel precursor material.

[0147] (2) Mix LiOH·H2O and ultra-high nickel precursor material evenly according to the molar ratio of Li:(Ni+Mn)=1.05:1, sinter, heat to 780℃ at 3℃ / min and hold for 15h under oxygen atmosphere, and then cool naturally to obtain ultra-high nickel cathode material.

[0148] Comparative Example 2

[0149] This embodiment provides a zirconium-doped ultra-high nickel cathode material, the chemical formula of which is LiNi. 0.94Mn 0.05 Zr 0.01 O2.

[0150] This comparative example provides a method for preparing the zirconium-doped ultra-high nickel cathode material, the method comprising the following steps:

[0151] (1) According to the chemical formula, NiSO4·6H2O, MnSO4·H2O and ZrO(NO3)2·2H2O were dissolved in deionized water in a molar ratio of Ni:Mn:Zr=0.94:0.05:0.01 to obtain a nickel-manganese-zirconium mixed salt solution with a total metal ion concentration of 1.5mol / L. A precipitant-complexing agent mixture containing 4mol / L NaOH and 2mol / L NH3·H2O was prepared (solvent: deionized water).

[0152] Under a nitrogen atmosphere, a nickel-manganese-zirconium mixed salt solution and a precipitant-complexing agent mixture were co-added to a reaction substrate (pure water + ammonia) with a pH of 11 for co-precipitation. The feed rate of the nickel-manganese-zirconium mixed salt solution was 50 L / h. The pH of the co-precipitation reaction was controlled at 11.0 ± 0.2 by the precipitant-complexing agent mixture. The reaction temperature was 55℃, the stirring speed was 450 rpm, and the reaction time was 12 h to obtain a zirconium-doped ultra-high nickel precursor material.

[0153] (2) Mix LiOH·H2O and zirconium-doped ultra-high nickel precursor material uniformly according to the molar ratio of Li:(Ni+Mn+Zr)=1.05:1, sinter, heat to 780℃ at 3℃ / min and hold for 15h under oxygen atmosphere, and then cool naturally to obtain zirconium-doped ultra-high nickel cathode material.

[0154] Comparative Example 3

[0155] This comparative example provides a multi-element doped ultra-high nickel cathode material, the chemical formula of which is LiNi. 0.88 Mn 0.075 Mo 0.02 Nb 0.01 W 0.015 O2.

[0156] This comparative example provides a method for preparing the multi-element doped ultra-high nickel cathode material. The difference between this method and Example 1 is that, according to the chemical formula, NiSO4·6H2O and MnSO4·H2O are dissolved in deionized water in a molar ratio of Ni:Mn = 0.88:0.075 to obtain a nickel-manganese mixed salt solution with a total metal ion concentration of 1.5 mol / L. (NH4)6Mo7O is then dissolved in water in a molar ratio of Mo:Nb = 0.02:0.01. 24Dissolving ·4H2O and C4H4NNbO9·xH2O in dilute ammonia water (pH=9) yields a molybdenum-niobium mixed salt solution with a total metal ion concentration of 0.1 mol / L. (NH4)6H2W 12 O 40 xH2O was dissolved in deionized water to obtain a tungsten salt solution with a total metal ion concentration of 0.05 mol / L. A nickel-manganese mixed salt solution, a molybdenum-niobium mixed salt solution, a tungsten salt solution, and a precipitant-complexing agent mixture were added to the crystal nucleation slurry in a co-current manner to carry out a second co-precipitation reaction. The feed rate of the tungsten salt solution was linearly increased from 0 to 32 L / h over a period of 4 h. The remaining preparation methods and parameters were consistent with those in Example 1.

[0157] Comparative Example 4

[0158] This comparative example provides a multi-element doped ultra-high nickel cathode material, the chemical formula of which is LiNi. 0.88 Mn 0.075 Nb 0.02 Zr 0.01 W 0.015 O2.

[0159] This comparative example provides a method for preparing the multi-element doped ultra-high nickel cathode material. The difference between this method and Example 1 is that, according to the chemical formula, NiSO4·6H2O and MnSO4·H2O are dissolved in deionized water at a molar ratio of Ni:Mn = 0.88:0.075 to obtain a nickel-manganese mixed salt solution with a total metal ion concentration of 1.5 mol / L. C4H4NNbO9·xH2O is dissolved in dilute ammonia water (pH = 9) to obtain a niobium salt solution with a total metal ion concentration of 0.1 mol / L. ZrO(NO3)2·2H2O and (NH4)6H2W are mixed at a molar ratio of Zr:W = 0.01:0.015. 12 O 40 • xH2O was dissolved in deionized water to obtain a zirconium-tungsten mixed salt solution with a total metal ion concentration of 0.05 mol / L. The nickel-manganese mixed salt solution, niobium salt solution, zirconium-tungsten mixed salt solution and precipitant-complexing agent mixture were added to the crystal nucleation slurry in a co-current manner to carry out a second co-precipitation reaction. The feed rate of the niobium salt solution was linearly increased from 0 to 40 L / h over a period of 4 h. The remaining preparation methods and parameters were consistent with those in Example 1.

[0160] Comparative Example 5

[0161] This comparative example provides a multi-element doped ultra-high nickel cathode material, the chemical formula of which is LiNi. 0.88 Mn 0.075 Mo 0.02 Zr 0.01 W 0.015O2.

[0162] This comparative example provides a method for preparing the multi-element doped ultra-high nickel cathode material. The difference between this method and Example 1 is that, according to the chemical formula, NiSO4·6H2O and MnSO4·H2O are dissolved in deionized water at a molar ratio of Ni:Mn = 0.88:0.075 to obtain a nickel-manganese mixed salt solution with a total metal ion concentration of 1.5 mol / L. (NH4)6Mo7O 24 ·4H2O was dissolved in dilute ammonia water (pH=9) to obtain a molybdenum salt solution with a total metal ion concentration of 0.1 mol / L. ZrO(NO3)2·2H2O and (NH4)6H2W were then mixed according to a molar ratio of Zr:W = 0.01:0.015. 12 O 40 xH2O was dissolved in deionized water to obtain a zirconium-tungsten mixed salt solution with a total metal ion concentration of 0.05 mol / L. The nickel-manganese mixed salt solution, molybdenum salt solution, zirconium-tungsten mixed salt solution and precipitant-complexing agent mixture were added to the crystal nucleation slurry in a co-current flow to carry out a second coprecipitation reaction. The feed rate of the molybdenum salt solution was linearly increased from 0 to 40 L / h over a period of 4 h. The remaining preparation methods and parameters were consistent with those in Example 1.

[0163] Comparative Example 6

[0164] This comparative example provides a multi-element doped ultra-high nickel cathode material, the chemical formula of which is LiNi. 0.88 Mn 0.07 Mo 0.02 Nb 0.02 Zr 0.01 O2.

[0165] This comparative example provides a method for preparing the multi-element doped ultra-high nickel cathode material. The difference between this method and Example 1 is that, according to the chemical formula, NiSO4·6H2O and MnSO4·H2O are dissolved in deionized water in a molar ratio of Ni:Mn = 0.88:0.07 to obtain a nickel-manganese mixed salt solution with a total metal ion concentration of 1.5 mol / L. (NH4)6Mo7O is then dissolved in water in a molar ratio of Mo:Nb = 0.02:0.02. 24·4H2O and C4H4NNbO9·xH2O were dissolved in dilute ammonia water (pH=9) to obtain a molybdenum-niobium mixed salt solution with a total metal ion concentration of 0.1 mol / L. ZrO(NO3)2·2H2O was dissolved in deionized water to obtain a zirconium salt solution with a total metal ion concentration of 0.05 mol / L. The nickel-manganese mixed salt solution, the molybdenum-niobium mixed salt solution, the zirconium salt solution, and the precipitant-complexing agent mixture were added to the crystal nucleation slurry in a co-current manner to carry out a second coprecipitation reaction. The feed rate of the zirconium salt solution was linearly increased from 0 to 32 L / h over a period of 4 h. The remaining preparation methods and parameters were consistent with those in Example 1.

[0166] Comparative Example 7

[0167] This embodiment provides a multi-element doped ultra-high nickel cathode material, the chemical formula of which is LiNi. 0.88 Mn 0.06 Mo 0.02 Nb 0.015 Mg 0.01 W 0.015 O2.

[0168] This invention provides a method for preparing the multi-element doped ultra-high nickel cathode material. The difference between this method and Example 1 is that, according to the chemical formula, the zirconium-tungsten mixed salt solution is replaced with a magnesium-tungsten mixed salt solution, and MgSO4·7H2O and (NH4)6H2W are mixed according to a molar ratio of Mg:W = 0.01:0.015. 12 O 40 • xH2O was dissolved in deionized water to obtain a magnesium-tungsten mixed salt solution with a total metal ion concentration of 0.05 mol / L. The remaining preparation methods and parameters were consistent with those in Example 1.

[0169] Application Example 1-10 and Comparative Application Example 1-7

[0170] The positive electrode materials provided in Examples 1-10 and Comparative Examples 1-7 were mixed with a sulfide solid electrolyte Li6PS5Cl and a carbon nanotube conductive agent at a mass ratio of 75:23:2, and a self-supporting positive electrode film was prepared using a dry film-forming process. Using Li6PS5Cl as the solid electrolyte layer and a lithium-indium alloy as the negative electrode, the layers were stacked and assembled in an argon glove box, and an isostatic pressure of 300 MPa was applied to obtain solid-state batteries, corresponding to Application Examples 1-10 and Comparative Application Examples 1-7, respectively.

[0171] After the solid-state batteries corresponding to use cases 1-10 and comparative application examples 1-7 were left to stand for 24 hours, their initial discharge specific capacity and initial coulombic efficiency at 0.1C, discharge specific capacity at 1C, and retention rate after 50 cycles at 1C were tested at 25℃ and a voltage range of 2.5V-4.3V. The specific test results are shown in Table 1.

[0172] Table 1

[0173]

[0174] The test results show that:

[0175] (1) As can be seen from Application Examples 1 to 6, the present invention uses four elements, Mo, Nb, Zr and W, as doping elements to achieve uniform multi-element doping of the entire particle from the core to the surface. The elements work together to play a role in lattice broadening and electron delocalization: by broadening the Li interlayer spacing, the Li... ＋ The diffusion coefficient is reduced by forming wide bandgap delocalized states in Li. ＋ The insertion / extraction barrier, combined with pinning to suppress oxygen evolution, together achieve the fast ion conductor effect, enabling multi-element doped ultra-high nickel cathode materials to have better discharge capacity, cycle stability and rate performance.

[0176] Specifically, the 0.1C initial discharge specific capacity of the solid-state battery is 205mAh / g-212mAh / g, the initial coulombic efficiency is 88.5%-89.5%, the 1C discharge specific capacity is 179mAh / g-190mAh / g, and the retention rate after 50 1C cycles is 95.2%-97.1%.

[0177] (2) As can be seen from Application Example 1 and Application Example 7, no doping elements are added in the initial nucleation stage (first coprecipitation reaction stage). In the doping stage (second coprecipitation reaction stage), the feed rate of the mixed salt solution of molybdenum-niobium and zirconium-tungsten corresponding to the doping elements Mo, Nb, Zr and W is linearly increased from 0 to the preset feed rate. The linear increase of the feed rate can avoid the composition segregation and lattice distortion caused by the simultaneous nucleation of multiple elements in the early stage of coprecipitation, ensure the controllability of the entire coprecipitation stage, ensure the structure of the obtained cathode material and the uniformity of element doping, and thus make the discharge capacity, cycle stability and rate performance better.

[0178] (3) As can be seen from Application Example 1 and Application Example 8, in the four-stage sintering process, the present invention induces the formation of oxygen vacancies by the oxygen-deficient environment, regulates the electronic structure, and can further enhance the electron delocalization effect and improve the electrochemical performance of the cathode material.

[0179] (4) As can be seen from Application Example 1 and Application Examples 9-10, the present invention further regulates the total molar amount of Mo, Nb, Zr and W to 3.5mol%-7.5mol% of the total molar amount of transition metal elements, which can maximize the synergistic modification effect of multiple elements while ensuring the integrity of the layered crystal structure and the absence of impurity phase formation.

[0180] (5) As can be seen from Application Example 1 and Comparative Application Example 1, if no doping is performed, the resulting ultra-high nickel cathode material has poor crystal structure stability. ＋ During the insertion / extraction process, the structure is prone to distortion and the surface is prone to the formation of by-reaction products, which leads to poor electrochemical performance and fails to meet the requirements of high electrochemical performance.

[0181] (6) As can be seen from Application Example 1 and Comparative Application Example 2, if only Zr is doped, it is a non-multi-element doped ultra-high nickel cathode material. The stabilizing effect of the doping element on the crystal structure is limited, and it cannot suppress Ni to the greatest extent. 2＋ Although the dissolution and structural phase transition of the system resulted in electrochemical performance superior to the undoped system, it was far inferior to the multi-element doped application example 1, which fully verified the key role of multi-element doping in improving the electrochemical performance of ultra-high nickel cathode materials.

[0182] (7) As can be seen from Application Example 1 and Comparative Application Examples 3-6, the present invention achieves better discharge capacity, cycle stability and rate performance of multi-element doped ultra-high nickel cathode material through the combined effect of four multi-element doping elements: Mo, Nb, Zr and W. If any one of them is omitted, the overall improvement of the electrochemical performance of the material cannot be achieved.

[0183] (8) As can be seen from Application Example 1 and Comparative Application Example 7, part of the Zr of this invention 4＋ Upon entering the Li site, the high valence state generates an electrostatic repulsion effect, pushing adjacent oxygen layers outward, thereby significantly widening the Li interlayer spacing, while Mg... 2＋ Due to the radius and Li ＋ Similar, Mg 2＋ After entering the Li site, the lattice broadening effect is not significant, basically maintaining the original interlayer spacing and failing to form an effective lattice broadening effect. Moreover, its main function is to reduce the Li content by occupying the Li site. ＋ -Ni 2＋ Mixed arrangement has a limited effect on improving ionic conductivity and a limited effect on improving the electrochemical performance of materials.

[0184] In summary, this invention uses four elements—Mo, Nb, Zr, and W—as doping elements to achieve uniform multi-element doping throughout the entire particle from the core to the surface. Each element works synergistically to broaden the lattice and regulate electron delocalization: by widening the Li interlayer spacing, the Li... ＋ The diffusion coefficient is reduced by forming wide bandgap delocalized states in Li. ＋ The insertion / extraction barrier, combined with pinning to suppress oxygen evolution, together achieve the fast ion conductor effect, enabling multi-element doped ultra-high nickel cathode materials to have better discharge capacity, cycle stability and rate performance.

[0185] The applicant declares that the above description is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention fall within the protection and disclosure scope of the present invention.

Claims

1. A multi-element doped ultra-high nickel cathode material, characterized in that, The chemical formula of the multi-element doped ultra-high nickel cathode material is LiNi. x Mn y Mo a Nb b Zr c W d O2, where 0.85≤x≤0.90, 0.03≤y≤0.08, 0.01≤a≤0.03, 0.01≤b≤0.02, 0.005≤c≤0.015, and 0.005≤d≤0.

015.

2. The multi-element doped ultra-high nickel cathode material according to claim 1, characterized in that, The total molar amount of Mo, Nb, Zr and W accounts for 3.5 mol% to 7.5 mol% of the total molar amount of transition metal elements.

3. A method for preparing a multi-element doped ultra-high nickel cathode material according to claim 1 or 2, characterized in that, The preparation method includes the following steps: (1) Prepare nickel-manganese mixed salt solution, molybdenum-niobium mixed salt solution and zirconium-tungsten mixed salt solution according to the general chemical formula; The nickel-manganese mixed salt solution and the precipitant-complexing agent mixture were added concurrently to the reaction substrate to carry out the first coprecipitation reaction, thereby obtaining the crystal nucleus slurry. The nickel-manganese mixed salt solution, the molybdenum-niobium mixed salt solution, the zirconium-tungsten mixed salt solution, and the precipitant-complexing agent mixture are added in parallel to the crystal nucleation slurry to carry out a second coprecipitation reaction; After the second coprecipitation reaction is completed, the feeding is stopped, and a crystallization reaction is carried out to obtain a multi-element doped precursor material; (2) The lithium source and the multi-element doped precursor material described in step (1) are mixed evenly and sintered to obtain a multi-element doped ultra-high nickel cathode material.

4. The preparation method according to claim 3, characterized in that, The total metal ion concentration in the nickel-manganese mixed salt solution in step (1) is 1 mol / L-3 mol / L; Preferably, the total metal ion concentration in the molybdenum-niobium mixed salt solution in step (1) is 0.08 mol / L-0.2 mol / L; Preferably, the total metal ion concentration in the zirconium-tungsten mixed salt solution in step (1) is 0.01 mol / L-0.1 mol / L; Preferably, the molar concentration of the precipitant in the precipitant-complexing agent mixture in step (1) is 1 mol / L-8 mol / L; Preferably, the molar concentration of the complexing agent in the precipitant-complexing agent mixture in step (1) is 0.1 mol / L-5 mol / L; Preferably, the pH of the reaction substrate in step (1) is 10-12.

5. The preparation method according to claim 3 or 4, characterized in that, The feed rate of the nickel-manganese mixed salt solution in step (1) is 45 L / h-55 L / h; Preferably, the pH of the first coprecipitation reaction in step (1) is 10.5-11.4; Preferably, the temperature of the first coprecipitation reaction in step (1) is 40℃-60℃; Preferably, the stirring rate of the first coprecipitation reaction in step (1) is 500 rpm-900 rpm; Preferably, the reaction time of the first coprecipitation reaction in step (1) is 1h-4h.

6. The preparation method according to any one of claims 3-5, characterized in that, In step (1), the feed rate of the molybdenum-niobium mixed salt solution is linearly increased from 0 to the preset feed rate of the molybdenum-niobium mixed salt solution; Preferably, the feed rate of the preset molybdenum-niobium mixed salt solution is 30L / h-50L / h; Preferably, the time for the feed rate of the molybdenum-niobium mixed salt solution to increase linearly from 0 to the preset value is 3-5 hours. Preferably, the feed rate of the zirconium-tungsten mixed salt solution in step (1) is linearly increased from 0 to a preset feed rate of the zirconium-tungsten mixed salt solution; Preferably, the preset feed rate of the zirconium-tungsten mixed salt solution is 25L / h-40L / h; Preferably, the time for the feed rate of the zirconium-tungsten mixed salt solution to increase linearly from 0 to the preset feed rate is 3h-6h.

7. The preparation method according to any one of claims 3-6, characterized in that, In step (1), the pH of the second coprecipitation reaction is 10.5-11.4; Preferably, the temperature of the second coprecipitation reaction in step (1) is 40℃-60℃; Preferably, the stirring rate of the second coprecipitation reaction in step (1) is 200 rpm to 700 rpm; Preferably, the reaction time of the second coprecipitation reaction in step (1) is 10h-18h; Preferably, the pH of the crystallization reaction in step (1) is 10.5-12.5; Preferably, the temperature of the crystallization reaction in step (1) is 50℃-70℃; Preferably, the stirring rate of the crystallization reaction in step (1) is 200 rpm to 700 rpm; Preferably, the reaction time of the crystallization reaction in step (1) is 4h-8h.

8. The preparation method according to any one of claims 3-7, characterized in that, The raw materials mixed in step (2) also include a flux; Preferably, the flux includes NH4Cl; Preferably, the amount of flux added is 0.1wt%-1wt% of the mass of the multi-element doped precursor material.

9. The preparation method according to any one of claims 3-8, characterized in that, The sintering in step (2) includes sequentially performing a first-stage sintering, a second-stage sintering, a third-stage sintering, a fourth-stage sintering, and a cooling stage; Preferably, the heating rate of the first sintering stage is 1℃ / min-5℃ / min; Preferably, the holding temperature for the first sintering stage is 350℃-530℃; Preferably, the holding time for the first sintering stage is 3-7 hours. Preferably, the heating rate of the two-stage sintering is 0.1℃ / min-0.8℃ / min; Preferably, the holding temperature for the two-stage sintering is 550℃-730℃; Preferably, the holding time for the two-stage sintering is 8h-12h; Preferably, the heating rate of the three-stage sintering is 1℃ / min-5℃ / min; Preferably, the holding temperature for the three-stage sintering is 750℃-850℃; Preferably, the holding time for the three-stage sintering is 12-15 hours; Preferably, the heating rate of the four-stage sintering is 2℃ / min-10℃ / min; Preferably, the holding temperature for the four-stage sintering is 850℃-1000℃; Preferably, the holding time for the four-stage sintering is 1-3 hours. Preferably, the sintering gas used in the first-stage sintering, the second-stage sintering, and the third-stage sintering each independently includes oxygen; Preferably, the sintering gas used in the four-stage sintering includes argon; Preferably, the cooling rate of the cooling section is 0.1℃ / min-0.8℃ / min; Preferably, the cooling section cools the temperature from the holding temperature of the four sintering sections to 300℃-500℃.

10. A solid-state battery, characterized in that, The solid-state battery includes the multi-element doped ultra-high nickel cathode material as described in claim 1 or 2, or the multi-element doped ultra-high nickel cathode material prepared by the preparation method described in any one of claims 3-9.

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