Core-shell manganese-based battery precursor, positive electrode material and preparation method therefor

Abstract

A core-shell manganese-based battery precursor, a positive electrode material, and a preparation method therefor. The core-shell manganese-based battery precursor comprises a core and a shell layer covering the surface of the core, wherein the core comprises nickel manganese hydroxide; the shell layer comprises nickel manganese hydroxide doped with a metal; the shell layer comprises, sequentially from the core outwards, a first outer shell and a second outer shell; and the doped metal comprises at least Zr, and the content of Zr in the second outer shell is greater than the content of Zr in the first outer shell. The precursor can provide a higher specific capacity for the positive electrode material and inhibit phase transition. The shell material can effectively prevent the core of the material from coming into contact with an electrolyte, avoid the precipitation of lattice oxygen and the dissolution of Mn, and can comprehensively improve the cycle performance and rate performance of a lithium-rich manganese-based battery under high voltage conditions.

Description

A core-shell manganese-based battery precursor, cathode material, and preparation method thereof Technical Field

[0001] This application relates to the field of cathode material precursor technology, and in particular to a core-shell type manganese-based battery precursor, cathode material and its preparation method. Background Technology

[0002] In the ever-evolving new energy industry, lithium-ion batteries, as a crucial energy storage technology, rely heavily on precursor structures and properties that directly impact the performance of cathode materials and battery energy storage efficiency. Leveraging its high specific capacity, high voltage platform, and low cost, lithium-rich manganese-based cathode materials have long been considered a promising sector, with leading battery and material companies prioritizing their industrial applications. Recent industry advancements suggest that lithium-rich manganese-based materials may be poised for a turning point in industrial application, ushering in a new era for cathode materials. CN117747806A discloses a method for preparing and applying a high-capacity lithium-rich manganese-based cathode material and its precursor. By controlling the grain size and crystal orientation of the material, the energy density and cycle performance of lithium-ion batteries are improved.

[0003] Under high voltage (4.5V) conditions, the structural damage and electrochemical instability of lithium-rich manganese-based cathode materials have become a significant concern. This is primarily because, at high voltages, the insertion / extraction of lithium ions in these materials can trigger changes in the material's crystal structure, leading to structural deformation, lattice defect formation, and particle dissolution, thereby affecting battery performance and lifespan. Secondly, the oxygen release reaction of lithium-rich manganese-based materials under high voltage conditions may exacerbate the risk of thermal runaway. When the battery operates at high voltage, oxygen ions in the cathode material may react adversely with the solvent in the electrolyte or the anode material, causing oxygen release and potentially leading to overheating, combustion, or even explosion.

[0004] Therefore, it is necessary to solve the problems of structural damage and electrochemical instability of lithium-rich manganese-based cathode materials under high voltage conditions, so as to realize the commercial application of high-performance and high-safety lithium-rich manganese-based batteries.

[0005] Summary of the Invention

[0006] The following is an overview of the subject matter described in detail herein. This overview is not intended to limit the scope of the claims.

[0007] This application provides a core-shell type manganese-based battery precursor, cathode material, and preparation method thereof. By coating the surface of the nickel manganese hydroxide core with two Zr-doped shells, and limiting the Zr content in the second shell to be greater than the Zr content in the first shell, the phase transition of the cathode material can be effectively suppressed, the structural stability of the precursor can be improved, and the erosion of the electrolyte can be suppressed, thereby improving the rate performance and cycle performance of the lithium-rich manganese-based battery at high voltage.

[0008] In a first aspect, this application provides a core-shell type manganese-based battery precursor, the core-shell type manganese-based battery precursor including a core and a shell covering the surface of the core;

[0009] The core comprises nickel-manganese hydroxide;

[0010] The shell layer comprises a nickel-manganese hydroxide doped with metal; from the core outwards, the shell layer comprises a first outer shell and a second outer shell in sequence;

[0011] The doped metal includes at least Zr, and the Zr content in the second shell is greater than the Zr content in the first shell.

[0012] The core-shell manganese-based battery precursor provided in this application features two Zr coating layers on the surface of the core, with the Zr content in the second shell being greater than that in the first shell. Zr doping forms a lithium zirconate (Li₂ZrO₃) coating layer on the surface of the lithium-rich manganese-based cathode material. Due to the strong bonding energy of the Zr-O bonds, this stabilizes the material structure and effectively suppresses electrolyte erosion during electrochemical cycling, inhibits surface lattice oxygen evolution, and suppresses the dissolution of transition metal ions. Simultaneously, the Li₂ZrO₃ phase formed on the surface after mixing with the lithium source inhibits the transformation of the material from a layered to a spinel-like structure, expanding the lithium-ion migration channels and effectively curbing capacity decay and cycle performance deterioration caused by the destruction of the layered structure. Therefore, Zr doping plays a crucial role in stabilizing the material structure and improving cycle stability and rate performance.

[0013] Furthermore, this application sets two Zr layers, with the Zr content in the second shell being higher than that in the first shell. This ensures that the coating layer formed by the second shell has high density and can effectively inhibit electrolyte corrosion. Meanwhile, the relatively low Zr content in the first shell is more conducive to ensuring the electrochemical performance of nickel and manganese. At the same time, it can be further improved by compounding with other metal elements to enhance cycle stability and rate performance.

[0014] In one embodiment, the composition of the nickel-manganese hydroxide in the core is Ni x Mn 1-x(OH)2, where 0.3≤x≤0.45, for example, can be 0.3, 0.32, 0.34, 0.35, 0.37, 0.39, 0.4, 0.42, 0.44 or 0.45, etc., but is not limited to the listed values. Other unlisted values ​​within this range also apply.

[0015] In one embodiment, the doped metal in the shell further includes any one or at least two combinations of Fe, Mg, Cu, Ca, Al, Zn, Cr, W, V, Nb, or Ti, wherein typical but non-limiting combinations are combinations of Fe and Mg, Cu and Mg, Fe and Cu, Ca and Mg, Al and Mg, and Fe and W, and may be combinations of at least two, and may further be combinations of at least two of Cr, W, V, or Nb, wherein typical but non-limiting combinations are combinations of Cr and W, V and W, Cr and V, and Nb and W.

[0016] In one embodiment, the first outer shell is composed of Ni. a Mn b MA c (OH)2, wherein 0.3≤a≤0.4, 0.5≤b≤0.65, 0.05≤c≤0.10, and a+b+c=1, wherein the MA includes Zr, and any one or a combination of at least two of Fe, Mg, Cu, Ca, Al, Zn, Cr, W, V, Nb or Ti, which may be selected as a combination of at least two, and may further be selected as a combination of at least two of Cr, W, V or Nb.

[0017] This application may further include doping the first casing with a combination of at least two of Cr, W, V or Nb, which can work in conjunction with Zr to better improve the cycle stability and rate performance of the battery.

[0018] Specifically, 0.3≤a≤0.4, for example, can be 0.3, 0.32, 0.33, 0.34, 0.35, 0.36, 0.37, 0.38, 0.39, or 0.4, but is not limited to the listed values; other unlisted values ​​within this range also apply. 0.5≤b≤0.65, for example, can be 0.5, 0.52, 0.54, 0.55, 0.57, 0.59, 0.6, 0.62, 0.64, or 0.65, but is not limited to the listed values; other unlisted values ​​within this range also apply. 0.05≤c≤0.10, for example, can be 0.05, 0.06, 0.07, 0.07, 0.08, 0.09, or 0.1, but is not limited to the listed values; other unlisted values ​​within this range also apply.

[0019] In one embodiment, the second outer shell is composed of Ni. d Mn e MB f (OH)2, where 0.3≤d≤0.4, 0.5≤e≤0.65, 0.1≤f≤0.15, and d+e+f=1, wherein MB is Zr.

[0020] The second shell of this application is doped with only Zr, which has a higher density and is more conducive to suppressing electrolyte erosion and improving cycle stability.

[0021] Specifically, 0.3≤d≤0.4, for example, can be 0.3, 0.32, 0.33, 0.34, 0.35, 0.36, 0.37, 0.38, 0.39 or 0.4, but is not limited to the listed values; other unlisted values ​​within this range also apply. 0.5≤e≤0.65, for example, can be 0.5, 0.52, 0.54, 0.55, 0.57, 0.59, 0.6, 0.62, 0.64 or 0.65, but is not limited to the listed values; other unlisted values ​​within this range also apply. 0.1≤f≤0.15, for example, can be 0.1, 0.11, 0.12, 0.13, 0.14 or 0.15, but is not limited to the listed values; other unlisted values ​​within this range also apply.

[0022] In one embodiment, the particle size D50 of the core-shell manganese-based battery precursor is 5 to 15 μm, for example, it can be 5 μm, 7 μm, 8 μm, 9 μm, 10 μm, 11 μm, 12 μm, 13 μm, 14 μm or 15 μm, but is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0023] In one embodiment, the particle size D50 of the core is 4 to 13 μm, for example, it can be 4 μm, 5 μm, 6 μm, 7 μm, 8 μm, 9 μm, 10 μm, 11 μm, 12 μm or 13 μm, but is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0024] In one embodiment, the thickness of the shell layer is 1 to 5 μm, for example, it can be 1 μm, 1.5 μm, 1.9 μm, 2.4 μm, 2.8 μm, 3.3 μm, 3.7 μm, 4.2 μm, 4.6 μm or 5 μm, but is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0025] In one embodiment, the thickness of the first outer shell is 0.5 to 2.5 μm, for example, it can be 0.5 μm, 0.8 μm, 1 μm, 1.2 μm, 1.4 μm, 1.7 μm, 1.9 μm, 2.1 μm, 2.3 μm or 2.5 μm, but is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0026] In one embodiment, the thickness of the second outer shell is 0.5 to 4.5 μm, for example, it can be 0.5 μm, 1 μm, 1.4 μm, 1.9 μm, 2.3 μm, 2.8 μm, 3.2 μm, 3.7 μm, 4.1 μm or 4.5 μm, but is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0027] Secondly, this application provides a method for preparing the core-shell manganese-based battery precursor described in the first aspect, the method comprising:

[0028] The core is prepared by first co-precipitation of nickel salt, manganese salt, precipitant and complexing agent in solvent;

[0029] The core is subjected to a second co-precipitation in a solvent containing a first doped metal salt, nickel salt, manganese salt, additives, precipitant, and complexing agent to coat the surface of the core with a first shell, thereby obtaining an intermediate.

[0030] The intermediate is subjected to a third co-precipitation in a solvent containing a second doped metal salt, nickel salt, manganese salt, additives, precipitant, and complexing agent to coat the surface of the core with a first shell, thereby obtaining the core-shell manganese-based battery precursor.

[0031] Both the first doped metal salt and the second doped metal salt include at least zirconium salt.

[0032] The preparation method provided in the second aspect of this application can produce cathode materials with excellent cycle stability and rate performance, and has broad application prospects.

[0033] Furthermore, the precursor material in this application does not contain cobalt. Cobalt, as a non-renewable metal, is scarce, and its limited resources cannot support the unlimited development potential of new energy vehicles. In addition, cobalt significantly impacts the cost of the cathode material itself. Due to increasing demand, cobalt prices continue to rise, posing a challenge to the battery industry's low-cost requirements. The scarcity and high price of cobalt will gradually limit the future of the electric vehicle market. Reducing or even eliminating cobalt in batteries would make electric vehicles more cost-effective. Therefore, developing lithium-rich manganese-based battery precursor materials with low cobalt content is crucial, and low-cobalt or even cobalt-free materials are gradually becoming the trend in battery development. The development of cobalt-free lithium-rich manganese-based battery precursor material systems achieves true cobalt-free cathode materials, reduces the cost of lithium-rich manganese-based precursor materials, and increases the energy density of cathode materials. This can reduce lithium battery costs and extend battery life, providing a key material solution for long-range power lithium batteries.

[0034] In one embodiment, the nickel salt, manganese salt, and zirconium salt in the first coprecipitate, second coprecipitate, and third coprecipitate are each independently selected from any one or at least two combinations of chloride, sulfate, acetate, or nitrate, wherein typical but non-limiting combinations are combinations of chloride and sulfate, combinations of acetate and sulfate, combinations of chloride and acetate, and combinations of nitrate and sulfate.

[0035] In one embodiment, the additives in the second and third coprecipitates each independently comprise any one or a combination of at least two of sodium sulfide, sodium chloride, sodium carbonate, or sodium oxide, wherein typical but non-limiting combinations are combinations of sodium sulfide and sodium chloride, combinations of sodium carbonate and sodium chloride, combinations of sodium sulfide and sodium carbonate, and combinations of sodium oxide and sodium carbonate.

[0036] In one embodiment, the complexing agent in the first coprecipitate, the second coprecipitate, and the third coprecipitate each independently comprises any one or a combination of at least two of ammonia, citric acid, lactic acid, or ethylenediaminetetraacetic acid, wherein typical but non-limiting combinations are a combination of ammonia and citric acid, a combination of lactic acid and citric acid, a combination of ammonia and lactic acid, or a combination of ethylenediaminetetraacetic acid and lactic acid.

[0037] In one embodiment, the precipitant in the first coprecipitate, the second coprecipitate, and the third coprecipitate each independently comprises any one or a combination of at least two of sodium hydroxide, sodium oxalate, sodium carbonate, or sodium acetate, wherein typical but non-limiting combinations are combinations of sodium hydroxide and sodium oxalate, combinations of sodium carbonate and sodium oxalate, combinations of sodium hydroxide and sodium carbonate, and combinations of sodium acetate and sodium oxalate.

[0038] In one embodiment, the temperatures of the first coprecipitation, the second coprecipitation, and the third coprecipitation are each independently 50 to 60°C, for example, 50°C, 52°C, 53°C, 54°C, 55°C, 56°C, 57°C, 58°C, 59°C, or 60°C, but are not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0039] In one embodiment, the first coprecipitation, the second coprecipitation, and the third coprecipitation are each carried out independently under stirring conditions.

[0040] In one embodiment, the rotation speeds of the first coprecipitate, the second coprecipitate, and the third coprecipitate are each independently 300 to 400 rpm, for example, 300 rpm, 312 rpm, 323 rpm, 334 rpm, 345 rpm, 356 rpm, 367 rpm, 378 rpm, 389 rpm, or 400 rpm, but are not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0041] In one embodiment, the pH of the first coprecipitate, the second coprecipitate, and the third coprecipitate is independently controlled to be 10.4 to 10.6, for example, it can be 10.4, 10.5, or 10.6, but is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0042] In one embodiment, the first coprecipitation, the second coprecipitation, and the third coprecipitation each independently comprise: passing a metal salt solution, a precipitant solution, and a complexing agent solution into a base solution containing a precipitant and a complexing agent to perform coprecipitation. The metal salt solutions in the first, second, and third coprecipitations respectively include combinations of nickel and manganese salts, a first doped metal salt, a combination of nickel and manganese salts, and a second doped metal salt, a combination of nickel and manganese salts;

[0043] In one embodiment, the temperature of the base liquid is 50-60°C, for example, it can be 50°C, 52°C, 53°C, 54°C, 55°C, 56°C, 57°C, 58°C, 59°C or 60°C, but is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0044] In one embodiment, the pH of the base solution is 9.5 to 11.5, for example, it can be 9.5, 9.8, 10, 10.2, 10.4, 10.7, 10.9, 11.1, 11.3 or 11.5, etc., but is not limited to the listed values, and other unlisted values ​​within this range are also applicable.

[0045] In one embodiment, the influent rate of the metal salt solution is 5 to 10 L / h, for example, it can be 5 L / h, 5.6 L / h, 6.2 L / h, 6.7 L / h, 7.3 L / h, 7.8 L / h, 8.4 L / h, 8.9 L / h, 9.5 L / h or 10 L / h, but is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0046] In one embodiment, the concentration of the metal salt in the metal salt solution is 70 to 150 g / L, for example, it can be 70 g / L, 79 g / L, 88 g / L, 97 g / L, 106 g / L, 115 g / L, 124 g / L, 133 g / L, 142 g / L or 150 g / L, but is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0047] In one embodiment, the flow rate of the precipitant solution is 1.5 to 4.0 L / h, for example, it can be 1.5 L / h, 1.8 L / h, 2.1 L / h, 2.4 L / h, 2.7 L / h, 2.9 L / h, 3.2 L / h, 3.5 L / h, 3.8 L / h or 4.0 L / h, but is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0048] In one embodiment, the infusion rate of the complexing agent solution is 0.1 to 2.5 L / h, for example, it can be 0.1 L / h, 0.4 L / h, 0.7 L / h, 0.9 L / h, 1.2 L / h, 1.5 L / h, 1.7 L / h, 2 L / h, 2.3 L / h, or 2.5 L / h, but is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0049] In one embodiment, the mass concentration of the precipitant solution is 20-40%, for example, it can be 20%, 23%, 25%, 27%, 29%, 32%, 34%, 36%, 38%, or 40%, but is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0050] In one embodiment, the mass concentration of the complexing agent solution is 5% to 20%, for example, it can be 5%, 7%, 9%, 10%, 12%, 14%, 15%, 17%, 19%, or 20%, etc., but is not limited to the listed values, and other unlisted values ​​within this range are also applicable.

[0051] In one embodiment, an additive-containing solution is further introduced into the second and third coprecipitates at a rate of 0.5 to 5.0 L / h. For example, the rate can be 0.5 L / h, 0.6 L / h, 1.0 L / h, 1.2 L / h, 1.3 L / h, 1.4 L / h, 1.5 L / h, 2.0 L / h, 2.2 L / h, 2.5 L / h, 3.0 L / h, 3.2 L / h, 3.5 L / h, 4.0 L / h, 4.2 L / h, 4.5 L / h, or 5.0 L / h, but is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0052] In one embodiment, the molar concentration of the additive-containing solution is 0.01 to 0.1 mol / L, for example, it can be 0.01 mol / L, 0.02 mol / L, 0.03 mol / L, 0.04 mol / L, 0.05 mol / L, 0.06 mol / L, 0.07 mol / L, 0.08 mol / L, 0.09 mol / L, or 0.1 mol / L, but is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0053] The preferred additive solution of this application has a molar concentration within the above-mentioned range, which allows the elements to achieve atomic-level mixing in the crystal lattice, enabling uniform co-precipitation and avoiding problems such as uneven precipitation and element segregation caused by excessively high additive concentration.

[0054] In one embodiment, the third co-precipitation process further includes aging and washing.

[0055] In one embodiment, the aging time is 4 to 10 hours, for example, it can be 4 hours, 4.7 hours, 5.4 hours, 6 hours, 6.7 hours, 7.4 hours, 8 hours, 8.7 hours, 9.4 hours or 10 hours, but is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0056] In one embodiment, the washing includes sequentially performing an alkaline wash and a water wash.

[0057] In one embodiment, the washing includes at least two alkaline washes followed by at least two water washes.

[0058] In one embodiment, the preparation method further includes drying the washed core-shell manganese-based battery precursor.

[0059] As an optional technical solution in this application, the preparation method includes the following steps:

[0060] Prepare a first base solution with pH 9.5–11.5 containing a precipitant and a complexing agent. Then, introduce a 70–150 g / L metal salt solution containing nickel and manganese salts at a rate of 5–10 L / h, a precipitant solution with a mass concentration of 20–40% at a rate of 1.5–4.0 L / h, and a complexing agent solution with a mass concentration of 5–20% at a rate of 0.1–2.5 L / h to the first base solution for first coprecipitation to prepare the core.

[0061] A second coprecipitation is performed by introducing a 70-150 g / L metal salt solution containing nickel salt, manganese salt, and a first doped metal salt into a system containing a core at a rate of 5-10 L / h; a 20-40% (w / w) precipitant solution at a rate of 1.5-4.0 L / h; a 5-20% (w / w) complexing agent solution at a rate of 0.1-2.5 L / h; and an additive solution at a rate of 0.5-5.0 L / h. This process coats the surface of the core with a first outer shell, yielding an intermediate.

[0062] A 70-150 g / L metal salt solution containing nickel salt, manganese salt, and a second doped metal salt is introduced into the system containing the intermediate at a rate of 5-10 L / h; a precipitant solution with a mass concentration of 20-40% is introduced at a rate of 1.5-4.0 L / h; a complexing agent solution with a mass concentration of 5-20% is introduced at a rate of 0.1-2.5 L / h; and an additive solution with a molar concentration of 0.01-0.1 mol / L is introduced at a rate of 0.5-5.0 L / h to perform a second coprecipitation and aging. A second shell is then coated onto the surface of the intermediate to obtain the core-shell manganese-based battery precursor.

[0063] This application does not impose any special restrictions on the drying process described above. Any device and method known to those skilled in the art for drying can be used. Adjustments can also be made according to the actual process. For example, it can be air drying, vacuum drying, oven drying, or freeze drying, or a combination of different methods.

[0064] Thirdly, this application provides a method for preparing a cathode material, the method comprising preparing it using the core-shell manganese-based battery precursor described in the first aspect.

[0065] The method for preparing the cathode material provided in the third aspect of this application is simple to operate and has broad prospects for industrialization.

[0066] In one embodiment, the method for preparing the cathode material includes: mixing a core-shell manganese-based battery precursor and a lithium source, and then sintering them to obtain the cathode material.

[0067] In one embodiment, the lithium source includes any one or a combination of at least two of lithium hydroxide, lithium carbonate, lithium chloride, lithium sulfate, or lithium nitrate.

[0068] In one embodiment, the molar ratio of lithium content to the sum of nickel and manganese in the lithium source is 0.7 to 1:1, for example, it can be 0.7:1, 0.74:1, 0.77:1, 0.8:1, 0.84:1, 0.87:1, 0.9:1, 0.94:1, 0.97:1 or 1:1, but is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0069] In one embodiment, the sintering atmosphere includes any one or a combination of at least two of air, oxygen, nitrogen, or hydrogen, wherein typical but non-limiting combinations are combinations of air and oxygen, combinations of nitrogen and oxygen, combinations of air and nitrogen, and combinations of hydrogen and oxygen.

[0070] In one embodiment, the sintering includes: heating to a first temperature at a first heating rate for a first holding, and then heating to a second temperature at a second heating rate for a second holding.

[0071] In one embodiment, the first heating rate is 3 to 8 °C / min, for example, it can be 3 °C / min, 3.6 °C / min, 4.2 °C / min, 4.7 °C / min, 5.3 °C / min, 5.8 °C / min, 6.4 °C / min, 6.9 °C / min, 7.5 °C / min or 8 °C / min, but is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0072] In one embodiment, the first temperature is 400 to 500°C, for example, it can be 400°C, 412°C, 423°C, 434°C, 445°C, 456°C, 467°C, 478°C, 489°C or 500°C, but is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0073] In one embodiment, the first heat preservation is 4 to 8 hours, for example, it can be 4 hours, 4.5 hours, 4.9 hours, 5.4 hours, 5.8 hours, 6.3 hours, 6.7 hours, 7.2 hours, 7.6 hours or 8 hours, but is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0074] In one embodiment, the second heating rate is 3 to 8 °C / min, for example, it can be 3 °C / min, 3.6 °C / min, 4.2 °C / min, 4.7 °C / min, 5.3 °C / min, 5.8 °C / min, 6.4 °C / min, 6.9 °C / min, 7.5 °C / min or 8 °C / min, but is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0075] In one embodiment, the second temperature is 600 to 700°C, for example, it can be 600°C, 612°C, 623°C, 634°C, 645°C, 656°C, 667°C, 678°C, 689°C or 700°C, but is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0076] In one embodiment, the second heat preservation time is 8 to 16 hours, for example, it can be 8 hours, 8.9 hours, 9.8 hours, 10.7 hours, 11.6 hours, 12.5 hours, 13.4 hours, 14.3 hours, 15.2 hours or 16 hours, but is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0077] Fourthly, this application provides a cathode material, which is prepared using the cathode material preparation method described in the third aspect.

[0078] The cathode material provided in the fourth aspect of this application has excellent performance and broad application prospects.

[0079] Compared with related technologies, this application has at least the following beneficial effects:

[0080] (1) The core-shell manganese-based battery precursor provided in this application effectively suppresses the phase transition of the cathode material and improves the structural stability of the precursor by coating the surface of the nickel-manganese hydroxide core with two Zr-doped shells, and limiting the Zr content in the second shell to be greater than that in the first shell. Under optional conditions, after the cathode material made from the core-shell manganese-based battery precursor is used to form a battery, the first discharge specific capacity at 0.1C is 261.3 mAh·g. -1 The above specifications are also mentioned, with a capacity retention rate of over 93.7% after 200 cycles at 0.1C; the initial discharge specific capacity at 1C is 245.9 mAh·g. -1 The above specifications demonstrate that the capacity retention rate after 200 cycles under C is above 91.5%, indicating broad application prospects.

[0081] (2) The preparation method of the core-shell manganese-based battery precursor provided in this application can effectively control the particle size and morphology of the lithium-rich manganese-based battery precursor material by controlling the wet co-precipitation conditions, and obtain a product with uniform particle size and appropriate size.

[0082] (3) The preparation method of the core-shell manganese-based battery precursor provided in this application improves the structural stability of the lithium-rich manganese-based precursor through the synergistic effect of different doped metals and coating.

[0083] After reading and understanding the accompanying diagrams and detailed descriptions, the other aspects can be understood. Attached Figure Description

[0084] The accompanying drawings are used to provide a further understanding of the technical solutions in this paper and form part of the specification. They are used together with the embodiments of this application to explain the technical solutions in this paper and do not constitute a limitation on the technical solutions in this paper.

[0085] Figure 1 is a SEM image of the core-shell manganese-based battery precursor prepared in Example 1 of this application. Detailed Implementation

[0086] To facilitate understanding of this application, 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 this application.

[0087] It should be understood that in the description of this application, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Therefore, a feature defined with "first," "second," etc., may explicitly or implicitly include one or more of that feature. In the description of this application, unless otherwise stated, "a plurality of" means two or more.

[0088] Example 1

[0089] This embodiment provides a core-shell type manganese-based battery precursor, which includes a core and a shell covering the surface of the core;

[0090] The core comprises nickel-manganese hydroxide;

[0091] The shell layer comprises a nickel-manganese hydroxide doped with metal; from the core outwards, the shell layer comprises a first outer shell and a second outer shell in sequence;

[0092] The composition of the nickel-manganese hydroxide in the core is Ni x Mn 1-x (OH)2, where x is 0.4;

[0093] The first outer shell is composed of Ni a Mn b MA c (OH)2, where a is 0.32, b is 0.60, c is 0.08, and the MA includes Zr and Nb (both 0.04);

[0094] The second outer shell is composed of Ni d Mn e Zr f (OH)2, where d is 0.3, e is 0.58, and f is 0.12.

[0095] The particle size D50 of the core-shell manganese-based battery precursor is 10 μm; the particle size D50 of the core is 8 μm; the thickness of the shell is 2 μm; the thickness of the first outer shell is 1 μm; and the thickness of the second outer shell is 1 μm.

[0096] This embodiment also provides a method for preparing the core-shell manganese-based battery precursor, the method comprising:

[0097] Prepare a 100L base solution with pH 11, EDTA concentration of 1g / L, and temperature of 53℃. Then, introduce a 100g / L metal salt solution containing nickel nitrate and manganese nitrate, a 35% sodium hydroxide solution, and a 15% EDTA solution at a flow rate of 2.5L / h into the base solution. Perform a first coprecipitation at 58℃ and 350rpm, and control the pH to 10.4–10.6 to prepare the core.

[0098] A 120 g / L metal salt solution containing nickel nitrate, manganese nitrate, zirconium nitrate, and niobium nitrate was introduced into a system containing a core at a rate of 6 L / h; a 25% sodium hydroxide solution was introduced at a rate of 1.5 L / h; a 15% EDTA solution was introduced at a rate of 2.0 L / h; and a 0.03 mol / L sodium sulfide solution was introduced at a rate of 3.0 L / h. A second coprecipitation was carried out at 55 °C and 380 rpm, with the pH controlled between 10.4 and 10.5. A first outer shell was then coated onto the surface of the core to obtain an intermediate.

[0099] A 100 g / L metal salt solution containing nickel nitrate, manganese nitrate, and zirconium nitrate was introduced into the system containing the intermediate at a rate of 10 L / h, followed by a 20% sodium hydroxide solution at a rate of 2.5 L / h, a 20% EDTA solution at a rate of 0.5 L / h, and a 0.07 mol / L sodium sulfide solution at a rate of 2.5 L / h. A third coprecipitation was carried out at 58 °C and 320 rpm, with the pH controlled at 10.4–10.6, and the mixture was aged for 6 h. A second shell was then coated onto the surface of the intermediate. The intermediate was then washed three times with liquid alkali and five times with deionized water, dried at 120 °C for 12 h, and sieved to remove iron, yielding the core-shell manganese-based battery precursor.

[0100] The SEM image of the core-shell manganese-based battery precursor prepared in this embodiment is shown in Figure 1. As can be seen from Figure 1, the core-shell manganese-based battery precursor prepared in this embodiment has a uniform particle size, a spherical morphology, and good sphericity.

[0101] This embodiment also provides a method for preparing a cathode material, the method comprising the following steps:

[0102] The above-mentioned core-shell manganese-based battery precursor and lithium hydroxide were mixed according to the molar ratio of lithium content in lithium hydroxide to the sum of nickel and manganese of 0.8:1, and the mixture was heated to 450°C at 5°C / min in air for 6 hours, and then heated to 650°C at 5°C / min for 12 hours to complete the sintering. The mixture was then naturally cooled at room temperature to obtain the cathode material.

[0103] Example 2

[0104] This embodiment provides a core-shell type manganese-based battery precursor, which includes a core and a shell covering the surface of the core;

[0105] The core comprises nickel-manganese hydroxide;

[0106] The shell layer comprises a nickel-manganese hydroxide doped with metal; from the core outwards, the shell layer comprises a first outer shell and a second outer shell in sequence;

[0107] The composition of the nickel-manganese hydroxide in the core is Ni x Mn 1-x (OH)2, where x is 0.3;

[0108] The first outer shell is composed of Ni a Mn b MA c (OH)2, wherein a is 0.3, b is 0.65, c is 0.05, and wherein MA includes Zr and V (0.03 and 0.02 respectively);

[0109] The second outer shell is composed of Ni d Mn e Zr f (OH)2, where d is 0.3, e is 0.55, and f is 0.15.

[0110] The particle size D50 of the core-shell manganese-based battery precursor is 5 μm; the particle size D50 of the core is 4 μm; the thickness of the shell is 1 μm; the thickness of the first outer shell is 0.5 μm; and the thickness of the second outer shell is 0.5 μm.

[0111] This embodiment also provides a method for preparing the core-shell manganese-based battery precursor, the method comprising:

[0112] Prepare a first base solution with pH 10.5, lactic acid concentration of 1.5 g / L, and temperature of 50 °C. Then, introduce a 120 g / L metal salt solution containing nickel nitrate and manganese nitrate, a 20% sodium hydroxide solution, and a 20% lactic acid solution at a flow rate of 5 L / h into the first base solution. Perform a first coprecipitation at 60 °C and 400 rpm, and control the pH to 10.4–10.6 to prepare the core.

[0113] A 110 g / L metal salt solution containing nickel nitrate, manganese nitrate, zirconium nitrate, and vanadium nitrate was introduced into a system containing a core at a rate of 10 L / h; a 20% sodium hydroxide solution was introduced at a rate of 4.0 L / h; a 5% lactic acid solution was introduced at a rate of 2.5 L / h; and a 0.1 mol / L sodium chloride solution was introduced at a rate of 1.5 L / h. A second coprecipitation was carried out at 60 °C and 400 rpm, with the pH controlled between 10.4 and 10.5. A first outer shell was then coated onto the surface of the core to obtain an intermediate.

[0114] A 150 g / L metal salt solution containing nickel nitrate, manganese nitrate, and zirconium nitrate was introduced into the system containing the intermediate at a rate of 8 L / h, followed by a 25% sodium hydroxide solution at a rate of 4.0 L / h, a 15% lactic acid solution at a rate of 0.1 L / h, and a 0.03 mol / L sodium chloride solution at a rate of 1.0 L / h. A third coprecipitation was carried out at 60 °C and 300 rpm, with the pH controlled at 10.4–10.5, and the mixture was aged for 8 h. A second shell was then coated onto the surface of the intermediate. The intermediate was then washed four times with liquid alkali and four times with deionized water, dried at 100 °C for 24 h, and sieved to remove iron, yielding the core-shell manganese-based battery precursor.

[0115] This embodiment also provides a method for preparing a cathode material, the method comprising the following steps:

[0116] The above-mentioned core-shell manganese-based battery precursor and lithium chloride were mixed according to the molar ratio of lithium content in lithium chloride to the sum of nickel and manganese of 0.78:1, and the mixture was heated to 400°C at 8°C / min for 4 hours in a hydrogen atmosphere, and then heated to 700°C at 3°C / min for 8 hours to complete the sintering. The mixture was then naturally cooled at room temperature to obtain the cathode material.

[0117] Example 3

[0118] This embodiment provides a core-shell type manganese-based battery precursor, which includes a core and a shell covering the surface of the core;

[0119] The core comprises nickel-manganese hydroxide;

[0120] The shell layer comprises a nickel-manganese hydroxide doped with metal; from the core outwards, the shell layer comprises a first outer shell and a second outer shell in sequence;

[0121] The composition of the nickel-manganese hydroxide in the core is Ni x Mn 1-x (OH)2, where x is 0.4;

[0122] The first outer shell is composed of Ni a Mn b MA c (OH)2, wherein a is 0.3, b is 0.5, c is 0.1, and wherein MA includes Zr and W (0.06 and 0.04 respectively);

[0123] The second outer shell is composed of Ni d Mn e Zr f (OH)2, where d is 0.4, e is 0.5, and f is 0.1.

[0124] The particle size D50 of the core-shell manganese-based battery precursor is 15 μm; the particle size D50 of the core is 11 μm; the thickness of the shell is 4 μm; the thickness of the first outer shell is 1 μm; and the thickness of the second outer shell is 3 μm.

[0125] This embodiment also provides a method for preparing the core-shell manganese-based battery precursor, the method comprising:

[0126] Prepare a first base solution with pH 9.5, ammonia concentration of 0.8 g / L, and temperature of 60 °C. Then, introduce a 75 g / L metal salt solution containing nickel sulfate and manganese sulfate at a rate of 10 L / h, a 28% sodium hydroxide solution at a rate of 1.5 L / h, and a 15% ammonia solution at a rate of 1.2 L / h into the first base solution. Perform a first co-precipitation at 50 °C and 300 rpm, and control the pH to 10.4–10.6 to prepare the core.

[0127] A 120 g / L metal salt solution containing nickel sulfate, manganese sulfate, zirconium sulfate, and ammonium tungstate was introduced into a system containing a core at a rate of 5 L / h; a 25% sodium hydroxide solution was introduced at a rate of 3.0 L / h; an 8% ammonia solution was introduced at a rate of 0.2 L / h; and a 0.01 mol / L sodium oxide solution was introduced at a rate of 4.5 L / h. A second coprecipitation was carried out at 50 °C and 300 rpm, with the pH controlled between 10.5 and 10.6. A first outer shell was then coated onto the surface of the core to obtain an intermediate.

[0128] A metal salt solution containing nickel sulfate, manganese sulfate, and zirconium sulfate (80 g / L) was introduced into the system containing the intermediate at a rate of 5 L / h, followed by a 30% sodium hydroxide solution at a rate of 2.0 L / h, a 10% ammonia solution at a rate of 0.3 L / h, and a 0.01 mol / L sodium oxide solution at a rate of 4.0 L / h. A third co-precipitation was carried out at 50 °C and 400 rpm, with the pH controlled at 10.5–10.6, and the mixture was aged for 8 h. A second shell was then coated onto the surface of the intermediate. The intermediate was then washed three times with liquid alkali and five times with deionized water, dried at 130 °C for 10 h, and sieved to remove iron, yielding the core-shell manganese-based battery precursor.

[0129] This embodiment also provides a method for preparing a cathode material, the method comprising the following steps:

[0130] The above-mentioned core-shell manganese-based battery precursor and lithium chloride were mixed according to the molar ratio of lithium content in lithium chloride to the sum of nickel and manganese of 0.78:1, and the mixture was heated to 400°C at 8°C / min for 4 hours in a hydrogen atmosphere, and then heated to 700°C at 3°C / min for 8 hours to complete the sintering. The mixture was then naturally cooled at room temperature to obtain the cathode material.

[0131] Example 4

[0132] This embodiment provides a core-shell manganese-based battery precursor. Except for the fact that f is 0.20 in the second shell and e is adjusted to 0.50 accordingly, and the preparation method is adjusted accordingly, the rest of the core-shell manganese-based battery precursor is the same as that in Embodiment 1, and will not be repeated here.

[0133] Example 5

[0134] This embodiment provides a core-shell manganese-based battery precursor. Except that the first shell does not contain Nb and is replaced with Zr, and the preparation method is adjusted accordingly, the core-shell manganese-based battery precursor is the same as that in Embodiment 1, and will not be described again here.

[0135] Example 6

[0136] This embodiment provides a core-shell manganese-based battery precursor. Except for the absence of sodium sulfide in the second precipitate and the corresponding adjustment of the preparation method, the core-shell manganese-based battery precursor is the same as that in Example 1, and will not be described again here.

[0137] Example 7

[0138] This embodiment provides a core-shell manganese-based battery precursor. Except for the absence of sodium sulfide in the third precipitate, the core-shell manganese-based battery precursor is the same as that in Example 1, and will not be described again here.

[0139] Example 8

[0140] This embodiment provides a core-shell manganese-based battery precursor. Except for the concentration of sodium sulfide in the third precipitate being 0.005 mol / L, the core-shell manganese-based battery precursor is the same as that in Example 1, and will not be described again here.

[0141] Example 9

[0142] This embodiment provides a core-shell manganese-based battery precursor. Except for the concentration of sodium sulfide in the third precipitate being 0.2 mol / L, the core-shell manganese-based battery precursor is the same as that in Example 1, and will not be described again here.

[0143] Example 10

[0144] This embodiment provides a core-shell manganese-based battery precursor. Except for controlling the pH to be 9.6-9.8 in the third precipitate, the core-shell manganese-based battery precursor is the same as that in Example 1, and will not be described again here.

[0145] Comparative Example 1

[0146] This comparative example provides a core-shell type manganese-based battery precursor. Except for the fact that f is 0.03 in the second shell and d is adjusted to 0.39 accordingly, the core-shell type manganese-based battery precursor is the same as that in Example 1, and will not be described again here.

[0147] Comparative Example 2

[0148] This comparative example provides a core-shell manganese-based battery precursor. Except for the metal salt solutions of the second and third precipitates being the same as those of the first precipitate, without the addition of any additional doped metal salts, the precursor is the same as in Example 1 and will not be described again here.

[0149] Comparative Example 3

[0150] This comparative example provides a core-shell manganese-based battery precursor, which is the same as that in Example 1 except that the third precipitation is not performed, and will not be described again here.

[0151] Comparative Example 4

[0152] This comparative example provides a core-shell manganese-based battery precursor, which is the same as that in Example 1 except that the second precipitation is not performed, and will not be described again here.

[0153] The lithium-rich manganese-based cathode materials obtained in the above examples and comparative examples were used to make the cathode of a lithium-ion battery. Then, a lithium metal sheet was used as the anode, Celgard 2400 was used as the separator, and 1 mol / L LiPF6 was used as the electrolyte. The batteries were assembled into CR2032 coin cells, and then electrochemical performance tests were conducted. The test conditions were a voltage range of 2-4.8V, a current density of 0.1C and 1C, and 200 cycles.

[0154] The test results of the above embodiments and comparative examples are shown in Table 1.

[0155] Table 1

[0156] The following points can be observed from Table 1:

[0157] (1) As can be seen from Examples 1-3, the core-shell manganese-based battery precursor and its preparation method provided in this application can improve the discharge specific capacity, cycle performance and rate performance of the battery material, wherein the initial discharge specific capacity at 0.1C is 261.3 mAh·g -1 The above specifications are also mentioned, with a capacity retention rate of over 93.7% after 200 cycles at 0.1C; the initial discharge specific capacity at 1C is 245.9 mAh·g. -1 The above specifications demonstrate that the capacity retention rate after 200 cycles under C is above 91.5%, indicating broad application prospects.

[0158] (2) Combining Examples 1 and 4, it can be seen that in Example 1, the second shell has f = 0.12 and e = 0.58. Compared with Example 4, where the second shell has f = 0.2 and e = 0.5, the 0.1C initial discharge specific capacity in Example 1 is 283.0 mAh·g. -1 Furthermore, the capacity retention rate after 200 cycles at 0.1C is 95.4%, and the initial discharge specific capacity at 1C is 265.2 mAh·g. -1 Furthermore, the capacity retention rate after 200 cycles at 1C is 93.7%, while the specific capacity at the first discharge at 0.1C in Example 4 is only 253.9 mAh·g. -1 Furthermore, the capacity retention rate after 200 cycles at 0.1C is only 90.1%, and the rate performance also decreases accordingly. This indicates that by controlling the composition of the second shell in a specific ratio, this application can further improve the rate performance, discharge specific capacity and cycle performance of the cathode material.

[0159] (3) As can be seen from the combined descriptions of Examples 1 and 5, in Example 1, the MA in the first casing includes Zr and Nb (both 0.04%). Compared to Example 5, where the MA in the first casing is only Zr, the 0.1C first discharge specific capacity in Example 1 is 283.0 mAh·g. -1Furthermore, the capacity retention rate after 200 cycles at 0.1C is 95.4%, and the initial discharge specific capacity at 1C is 265.2 mAh·g. -1 Furthermore, the capacity retention rate after 200 cycles at 1C is 93.7%, while the specific capacity at the first discharge at 0.1C in Example 5 is only 240.8 mAh·g. -1 Furthermore, the capacity retention rate after 200 cycles at 0.1C is only 84.8%, and the rate performance also decreases accordingly. This indicates that by selecting other elements in the first shell to be used in combination with Zr, the rate performance, discharge specific capacity and cycle performance of the cathode material can be further improved.

[0160] (4) As can be seen from Examples 1 and 6-9, this application can further improve the rate performance, discharge specific capacity and cycle performance of the cathode material by introducing sodium sulfide solution into both the second and third precipitates and controlling the concentration of sodium sulfide.

[0161] (5) Combining Examples 1 and 10, it can be seen that the pH of the third coprecipitation in Example 1 is 10.4–10.6, compared to the pH of 9.6–9.8 controlled in the third precipitation in Example 10. The initial discharge specific capacity at 0.1C in Example 1 is 283.0 mAh·g. -1 Furthermore, the capacity retention rate after 200 cycles at 0.1C is 95.4%, and the initial discharge specific capacity at 1C is 265.2 mAh·g. -1 Furthermore, the capacity retention rate after 200 cycles at 1C is 93.7%, while the initial discharge specific capacity at 0.1C in Example 10 is only 255.9 mAh·g. -1 Furthermore, the capacity retention rate after 200 cycles at 0.1C is only 90.7%, and the initial discharge specific capacity at 1C is only 237.8 mAh·g. -1 Furthermore, the capacity retention rate after 200 cycles at 1C is only 88.3%, indicating that by controlling the pH in the third precipitate within a specific range, this application can further improve the rate performance, discharge specific capacity, and cycle performance of the cathode material.

[0162] (6) In Comparative Example 1, f is 0.03 in the second casing, and d is adjusted accordingly to 0.39, resulting in a final 0.1C first discharge specific capacity of only 229.3 mAh·g. -1 Furthermore, the capacity retention rate after 200 cycles at 0.1C was only 78.4%, indicating a significant decrease in discharge specific capacity and cycle performance. In Comparative Example 2, the metal salt solutions for the second and third precipitates were the same as those for the first precipitate, with no additional doped metal salts added, resulting in a final initial discharge specific capacity of only 218.4 mAh·g at 0.1C. -1Furthermore, the capacity retention rate after 200 cycles at 0.1C was only 72.8%, and the rate performance also decreased significantly. In Comparative Examples 3 and 4, the third and second precipitations were not performed, resulting in a significant decrease in the rate performance, discharge specific capacity, and cycle performance of the cathode material. This indicates that by adopting a three-step co-precipitation method and controlling the doping of metal salts, and strictly controlling the proportions in the product, this application can improve the electrochemical performance of the material.

[0163] This application illustrates its detailed features through the above embodiments, but it is not limited to these detailed features, meaning that this application does not necessarily rely on them for implementation. Those skilled in the art should understand that any improvements to this application, equivalent substitutions for selected technical features, additions of auxiliary technical features, and selection of specific methods all fall within the protection and disclosure scope of this application.

Claims

1. A core-shell type manganese-based battery precursor, comprising a core and a shell covering the surface of the core; The core comprises nickel-manganese hydroxide; The shell layer comprises a nickel-manganese hydroxide doped with metal; from the core outwards, the shell layer comprises a first outer shell and a second outer shell in sequence; The doped metal includes at least Zr, and the Zr content in the second shell is greater than the Zr content in the first shell.

2. The core-shell manganese-based battery precursor according to claim 1, wherein, The composition of the nickel-manganese hydroxide in the core is Ni x Mn 1-x (OH)2, where 0.3≤x≤0.

45.

3. The core-shell manganese-based battery precursor according to claim 1 or 2, wherein, The shell layer is also doped with metals including any one or a combination of at least two of Fe, Mg, Cu, Ca, Al, Zn, Cr, W, V, Nb or Ti, and may be selected as a combination of at least two, and may further be selected as a combination of at least two of Cr, W, V or Nb.

4. The core-shell manganese-based battery precursor according to any one of claims 1 to 3, wherein, The first outer shell is composed of Ni a Mn b MA c (OH)2, wherein 0.3≤a≤0.4, 0.5≤b≤0.65, 0.05≤c≤0.10, and a+b+c=1, wherein the MA includes Zr, and any one or a combination of at least two of Fe, Mg, Cu, Ca, Al, Zn, Cr, W, V, Nb or Ti, which may be selected as a combination of at least two, and may further be selected as a combination of at least two of Cr, W, V or Nb.

5. The core-shell manganese-based battery precursor according to any one of claims 1 to 4, wherein, The second outer shell is composed of Ni d Mn e MB f (OH)2, where 0.3≤d≤0.4, 0.5≤e≤0.65, 0.1≤f≤0.15, and d+e+f=1, wherein MB is Zr.

6. The core-shell manganese-based battery precursor according to any one of claims 1 to 5, wherein, The particle size D50 of the core-shell manganese-based battery precursor is 5–15 μm; Optionally, the kernel's particle size D50 is 4–13 μm; Optionally, the thickness of the shell layer is 1–5 μm; Optionally, the thickness of the first outer shell is 0.5–2.5 μm; Optionally, the thickness of the second outer shell is 0.5 to 4.5 μm.

7. A method for preparing a core-shell manganese-based battery precursor according to any one of claims 1 to 6, comprising: The core is prepared by first co-precipitation of nickel salt, manganese salt, precipitant and complexing agent in solvent; The core is subjected to a second co-precipitation in a solvent containing a first doped metal salt, nickel salt, manganese salt, additives, precipitant, and complexing agent to coat the surface of the core with a first shell, thereby obtaining an intermediate. The intermediate is subjected to a third co-precipitation in a solvent containing a second doped metal salt, nickel salt, manganese salt, additives, precipitant, and complexing agent to coat the surface of the core with a first shell, thereby obtaining the core-shell manganese-based battery precursor. Both the first doped metal salt and the second doped metal salt include at least zirconium salt.

8. The preparation method according to claim 7, wherein, The nickel salt, manganese salt, and zirconium salt in the first coprecipitate, the second coprecipitate, and the third coprecipitate are each independently selected from any one or a combination of at least two of chloride salts, sulfate salts, acetate salts, or nitrate salts.

9. The preparation method according to claim 7 or 8, wherein, The additives in the second and third coprecipitates each independently include any one or a combination of at least two of sodium sulfide, sodium chloride, sodium carbonate, or sodium oxide.

10. The preparation method according to any one of claims 7 to 9, wherein, The complexing agent in the first coprecipitate, the second coprecipitate, and the third coprecipitate each independently includes any one or a combination of at least two of ammonia, citric acid, lactic acid, or ethylenediaminetetraacetate. Optionally, the precipitant in the first coprecipitate, the second coprecipitate, and the third coprecipitate each independently includes any one or a combination of at least two of sodium hydroxide, sodium oxalate, sodium carbonate, or sodium acetate.

11. The preparation method according to any one of claims 8 to 10, wherein, The temperatures for the first coprecipitation, the second coprecipitation, and the third coprecipitation are each independently 50–60°C; Optionally, the first coprecipitation, the second coprecipitation, and the third coprecipitation are each carried out independently under stirring conditions; Optionally, the rotation speeds of the first coprecipitate, the second coprecipitate, and the third coprecipitate are each independently 300–400 rpm; Optionally, the pH of each of the first coprecipitate, the second coprecipitate, and the third coprecipitate is independently controlled to be 10.4 to 10.

6.

12. The preparation method according to any one of claims 7 to 11, wherein, The first coprecipitation, the second coprecipitation, and the third coprecipitation each independently include: passing a metal salt solution, a precipitant solution, and a complexing agent solution into a base solution containing a precipitant and a complexing agent to perform coprecipitation; the metal salt solutions in the first coprecipitation, the second coprecipitation, and the third coprecipitation respectively include a combination of nickel salt and manganese salt, a first doped metal salt, a combination of nickel salt and manganese salt, and a second doped metal salt, a combination of nickel salt and manganese salt; Optionally, the temperature of the base liquid is 50–60°C; Optionally, the pH of the substrate solution is 9.5–11.5; Optionally, the influent rate of the metal salt solution is 5–10 L / h; Optionally, the concentration of the metal salt in the metal salt solution is 70–150 g / L; Optionally, the flow rate of the precipitant-containing solution is 1.5–4.0 L / h; Optionally, the influent rate of the complexing agent-containing solution is 0.1–2.5 L / h; Optionally, the mass concentration of the precipitant-containing solution is 20-40%; Optionally, the mass concentration of the complexing agent-containing solution is 5-20%; Optionally, an additive-containing solution is also introduced into the second and third coprecipitates at a rate of 0.5–5.0 L / h. Optionally, the molar concentration of the additive-containing solution is 0.01–0.1 mol / L; Optionally, the third co-precipitation process further includes aging and washing; Optionally, the aging time is 4 to 10 hours; Optionally, the washing process includes sequentially performing alkaline washing and water washing; Optionally, the washing process includes at least two alkaline washes followed by at least two water washes. Optionally, the preparation method further includes drying the washed core-shell manganese-based battery precursor.

13. A method for preparing a cathode material, comprising preparing it using the core-shell manganese-based battery precursor as described in any one of claims 1 to 6.

14. The method for preparing the cathode material according to claim 13, wherein, The method for preparing the cathode material includes: mixing a core-shell manganese-based battery precursor and a lithium source, and then sintering them to obtain the cathode material; Optionally, the lithium source includes any one or a combination of at least two of lithium hydroxide, lithium carbonate, lithium chloride, lithium sulfate, or lithium nitrate; Optionally, the molar ratio of lithium content to the sum of nickel and manganese in the lithium source is 0.7 to 1:1; Optionally, the sintering atmosphere includes any one or a combination of at least two of air, oxygen, nitrogen or hydrogen. Optionally, the sintering includes: heating to a first temperature at a first heating rate and holding for a first time, and then heating to a second temperature at a second heating rate and holding for a second time. Optionally, the first heating rate is 3–8 °C / min; Optionally, the first temperature is 400–500°C; Optionally, the first heat preservation is performed for 4 to 8 hours; Optionally, the second heating rate is 3–8 °C / min; Optionally, the second temperature is 600–700°C; Optionally, the second insulation period is 8 to 16 hours.

15. A cathode material, wherein the cathode material is prepared by the method for preparing cathode material according to claim 13 or 14.

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