Agglomerated multi-component cathode material, method for producing the same, use thereof, and lithium ion battery

Abstract

A class-aggregated multi-component cathode material, a method for manufacturing the same, uses thereof, and a lithium-ion battery. The chemical formula of the class-aggregated multi-component cathode material is Li a Ni x Co y Mn z M b O2, where 0.9 ≦ a ≦ 1.1, 0.5 ≦ x < 1, 0 < y < 0.5, 0 < z < 0.5, 0 ≦ b < 0.05, M is at least one of V, Ta, Cr, La, Al, Ce, Er, Ho, Y, Mg, Sr, Ba, Ra, Zr, Fe, Ca, Zn, B, W, Nb, Cd, Pb, Si, Mo, Cu, Sr, and Ti, and it is a secondary particle in which primary particles aggregate. The primary particles are spherical or quasi-spherical, and the average particle size D S of the primary particles is 0.9 - 2.4 μm, the average particle size D L of the secondary particles is 5 - 15 μm, and the value range of D L / D S is 5 - 16. The class-aggregated multi-component cathode material has a high energy density and excellent rate performance and cycle stability.

Description

Technical Field

[0001] The present invention relates to the field of lithium-ion battery technology, and specifically to an aggregated multi-component cathode material, a method for manufacturing the same, and a lithium-ion battery.

Background Art

[0002] In recent years, energy and environmental issues have attracted increasing attention. The development of new energy vehicles in the world has started from hybrids and then entered an era centered on batteries. Pure electric and plug-in hybrids have become the main forces of true policy support for new energy.

[0003] High safety and long endurance are the development trends of electric vehicles. In order to meet the higher demand for electric vehicles, power lithium batteries need to have a higher energy density and better cycle stability. Among the lithium battery industrial chain, the link with the largest market scale and the highest production value is the cathode material. Moreover, its performance determines the energy density, life, rate performance, etc. of the battery. The cathode material has become the core and important material of lithium batteries.

[0004] Ternary materials have the characteristics of high energy density, good cycle stability, and good safety. The current mainstream ternary materials in the market are aggregated materials and single crystal materials. The aggregated materials have good rate performance but slightly poor cycle performance. The single crystal materials have good cycle performance but small particle size, low production efficiency, and slightly poor rate performance.

[0005] In order to obtain a cathode material with a high energy density and high structural stability, it is necessary to rationally design the material structure to balance the energy density, rate performance, and cycle stability of the material.

[0006] The related art discloses a micron-order sheet-like single-crystal structure aggregate of a ternary positive electrode material and a method for producing the same. First, an improved chemical co-precipitation method is used to prepare a micron-order spherical precursor with densely stacked nanosheets, and the D50 of the precursor is 6-8 μm. Then, the precursor is sequentially and thoroughly mixed with an appropriate amount of fluxing agent and lithium salt. Finally, two high-temperature sintering steps are carried out in a high-temperature sintering furnace. Finally, a micron-order sheet-like single-crystal structure aggregate of a ternary positive electrode material is obtained. This can combine the advantages of both the single-crystal structure and the aggregate structure. However, the sheet-like single-crystal structure The pressure resistance of the sheet-like structure is low, and the aggregates formed in the sheet structure do not easily form regular spherical shapes, and the primary particles do not easily accumulate closely together, resulting in weak mutual bonding. As a result, cracking and slippage between primary particles are likely to occur during the battery electrode piece production process, leading to structural collapse and reduced cycle performance. In addition, the grain boundary gaps of the aggregates accumulated in the sheet structure are large, and the grain boundaries and surfaces are not protected by a ductile coating layer. During the battery cycle process, the electrolyte easily reaches the surfaces of the primary particles through the grain boundaries, causing the primary particles to be eroded by the electrolyte from the surface to the interior, resulting in a reduced cycle retention rate. Summary of the Invention [Problem to be solved by the invention]

[0007] The present invention is intended to overcome the problem that conventional ternary cathode materials cannot simultaneously achieve energy density, rate performance, and cycle stability. [Means for solving the problem]

[0008] In order to achieve the above object, a first aspect of the present invention provides a near-agglomerated multi-component positive electrode material, the multi-component positive electrode material having a structure shown in Formula I: Li a Ni x Co y Mn z M b O2 formula I In formula I, 0.9 ≦ a ≦ 1.1, 0.5 ≦ x < 1, 0 < y < 0.5, 0 < z < 0.5, 0 ≦ b < 0.05, M is at least one of V, Ta, Cr, La, Al, Ce, Er, Ho, Y, Mg, Sr, Ba, Ra, Zr, Fe, Ca, Zn, B, W, Nb, Cd, Pb, Si, Mo, Cu, Sr and Ti, The multi-component cathode material is secondary particles in which primary particles are aggregated. The primary particles are spherical or quasi-spherical, and the average particle size D of the primary particles S is 0.9 - 2.4 μm, and the average particle size D of the secondary particles L is 5 - 15 μm, and D L / D S takes a value range of 5 - 16.

[0009] The second aspect of the present invention provides a method for manufacturing an agglomerated multi-component cathode material. The manufacturing method includes: (1) Mixing a nickel source, a first cobalt source, a manganese source, a complexing agent and a precipitating agent for coprecipitation reaction to obtain a slurry, and then aging, pressure filtering, washing and drying the slurry in sequence to obtain a nickel-cobalt-manganese ternary precursor; (2) Mixing the nickel-cobalt-manganese ternary precursor and a lithium source for the first high-temperature sintering, and performing pulverization and sieving processes in sequence to obtain an agglomerated cathode material process product; (3) Mixing the agglomerated cathode material process product and a second cobalt source for the second high-temperature sintering, and performing pulverization and sieving processes in sequence to obtain an agglomerated multi-component cathode material.

[0010] The third aspect of the present invention provides an agglomerated multi-component cathode material manufactured by the manufacturing method described in the second aspect.

[0011] The fourth aspect of the present invention provides the use of the agglomerated multi-component cathode material described in the first aspect or the third aspect, or the manufacturing method described in the second aspect in a lithium-ion battery.

[0012] The fifth aspect of the present invention provides a lithium-ion battery including the agglomerated multi-component cathode material described in the first aspect or the third aspect.

Advantages of the Invention

[0013] By the above technical solution, the present invention has the following advantages.

[0014] 1. In the prior art, the particle size of the primary particles of the aggregated ternary cathode material is usually 0.2 - 0.6 μm. The agglomerated multi-component cathode material according to the present invention is secondary particles in which the primary particles are agglomerated. The primary particles are spherical or quasi-spherical, are more closely deposited, have a strong mutual binding force, a high tap density, and the formed secondary particles are also spherical or quasi-spherical. In the present invention, the morphological characteristics of the primary particles and the secondary particles are advantageous for improving the energy density and cycle performance of the battery. The average particle size D of the primary particles S is 0.9 - 2.4 μm, which is close to the size of the single-crystalline ternary cathode material. The conventional aggregated ternary cathode material is easily cracked during the production process of the electrode sheet, and during the cycling process, due to the expansion and contraction of the particles, the primary particles are easily separated from each other, destroying the material structure and reducing the electrical performance. The agglomerated multi-component cathode material according to the present invention can compensate for the defects of the aggregated material, has a stronger pressure resistance ability, and even when separation occurs between the primary particles during the pressing and cycling processes, the performance of the separated primary particles is still the same as that of the single-crystalline material, ensuring the stability of the electrical performance of the cathode material during the cycling process.

[0015] 2. In the agglomerated multi-component cathode material according to the present invention, the average particle size D of the secondary particles L is 5 - 15 μm, which is close to the aggregated material and larger than the primary particles of the single-crystalline material. After manufacturing the electrode sheet, the binding between the particles of the single-crystalline material becomes closer, the rate performance is better, fewer conductive agents and binders are required, which is advantageous for improving the proportion of the active material, and the tap density of the electrode sheet is larger, improving the energy density of the battery.

[0016] 3. In the agglomerated multi-component cathode material according to the present invention, the grain boundaries of the primary particles and the surface of the secondary particles are rich in Co. Let the Co molar content at the center of the primary particles be K1, the Co molar content at the grain boundaries of the primary particles be K2, and the Co molar content at the surface of the secondary particles be K3. Then K2 - K1 ≥ 0.5% and K3 - K1 ≥ 1.5%. Since the primary particles of the multi-component cathode material of the present invention are large, the gaps at the grain boundaries between the primary particles are large. After coating the ductile cobalt-containing compound on the agglomerated cathode material process product and undergoing high-temperature sintering, the cobalt element can not only be coated on the surface of the secondary particles, but also enter the interior of the secondary particles along the grain boundaries of the primary particles, aggregate at the interfaces between the primary particles, and achieve the purpose of simultaneously coating the primary particles and the secondary particles with the cobalt element. In the process of making the electrode sheet and cycling, even if the secondary particles are pulverized or the electrolyte reaches the surface of the primary particles through the grain boundaries, the exposed surface of the primary particles is still protected by the coating layer, improving the structural stability of the material, suppressing the erosion of the electrolyte, and improving the cycling stability and safety.

Brief Description of the Drawings

[0017]

Figure 1

Figure 2

Figure 3

Figure 4

Modes for Carrying Out the Invention

[0018] The endpoints and any values disclosed in this specification are not limited to such exact ranges or values, and should be understood to include values close to these ranges or values. In the case of a numerical range, between the endpoint values of each range, between each endpoint value and a single point value, and between single point values, one or more new numerical ranges are obtained by combining them with each other, and these numerical ranges are regarded as specifically disclosed in the specification.

[0019] In the present invention, unless otherwise clearly indicated, "first" and "second" do not represent the order before and after, nor are they for limiting individual materials or operations, but only for distinguishing individual materials or operations. For example, "first cobalt source" and "second cobalt source" are only distinguished to indicate that these are not the same cobalt source, and "first high-temperature sintering" and "second high-temperature sintering" are only distinguished to indicate that they are not the same high-temperature sintering operation.

[0020] The first aspect of the present invention provides a pseudo-aggregated multi-component cathode material, and the multi-component cathode material has a structure shown in Formula I. Li a Ni x Co y Mn z M b O2 Formula I In Formula I, 0.9 ≦ a ≦ 1.1, 0.5 ≦ x < 1, 0 < y < 0.5, 0 < z < 0.5, 0 ≦ b < 0.05, and M is at least one of V, Ta, Cr, La, Al, Ce, Er, Ho, Y, Mg, Sr, Ba, Ra, Zr, Fe, Ca, Zn, B, W, Nb, Cd, Pb, Si, Mo, Cu, Sr, and Ti. The multi-component cathode material is secondary particles in which primary particles are aggregated, the primary particles are spherical or quasi-spherical, and the average particle size D of the primary particles S is 0.9 - 2.4 μm, the average particle size D of the secondary particles L is 5 - 15 μm, and the value range of D L / D S is 5 - 16.

[0021] According to some embodiments of the present invention, for the agglomerated multi-component cathode material, the sizes of the primary particles and the secondary particles are controlled, and by combining the value ranges of D L / D S , the formed multi-component cathode material becomes agglomerated, combines the excellent performances of single-crystalline materials and agglomerated materials, and can combine the high energy density, rate performance and cycle stability of the cathode material.

[0022] According to some embodiments of the present invention, preferably, the agglomerated multi-component cathode material has a spherical or quasi-spherical shape. The morphology of the agglomerated multi-component cathode material is characterized by a scanning electron microscope (SEM).

[0023] According to some embodiments of the present invention, the grain boundaries of the primary particles and the surfaces of the secondary particles are rich in Co. Let the Co molar content at the center of the primary particles be K1, the Co molar content at the grain boundaries of the primary particles be K2, and the Co molar content at the surfaces of the secondary particles be K3. Then K2 - K1 ≥ 0.5%, preferably, K2 - K1 ≥ 1%, and K3 - K1 ≥ 1.5%, preferably, K3 - K1 ≥ 3%. The "center" at the center of the primary particles does not refer to the true center, but refers to the other main parts excluding the grain boundaries of the primary particles and the surfaces of the secondary particles.

[0024] Adopting the above preferred embodiments is advantageous for forming a uniform coating layer on the grain boundaries and the surfaces of the secondary particles, increasing the mobility of lithium ions, suppressing the erosion of the electrolyte, and improving the rate and cycle performance.

[0025] According to some embodiments of the present invention, preferably, in Formula I, 1 ≤ a ≤ 1.1 and 0.0005 ≤ b ≤ 0.01.

[0026] According to some embodiments of the present invention, preferably, M is at least one of Mg, W, V, Ti, La, Nb, Si, Al, and B.

[0027] According to some embodiments of the present invention, preferably, the average particle size D of the primary particles S is 1.2 - 1.8 μm.

[0028] According to some embodiments of the present invention, preferably, the average particle size D of the secondary particles L is 7 - 13 μm.

[0029] According to some embodiments of the present invention, preferably, D L / D S is in the range of 7 - 12.

[0030] Adopting the above preferred embodiment, setting D S to 1.2 - 1.8 μm, when Ds is greater than 1.8 μm, the primary particles become larger, the material rate performance becomes lower, and the product performance may approach that of single-crystalline materials. When Ds is less than 1.2 μm, the primary particles become smaller, the structural stability is poor, the cycle performance is low, and the product performance may approach that of agglomerated materials. Adopting the above preferred embodiment, setting D L to 7 - 13 μm, when D L is greater than 13 μm, the secondary particles become larger, the mobility of lithium ions becomes lower, and the speed becomes worse. When D L is less than 7 μm, the secondary particles become smaller, the compaction density is low, leading to a decrease in energy density and deterioration of the cycle. Adopting the above preferred embodiment, setting the value range of D L / D S to 7 - 12, when D L / D S is greater than 12, the number of primary particles in the secondary particles increases, forming many grain boundaries, the pressure resistance performance of the material decreases, and the product performance may approach that of aggregates. The electrode sheet is likely to be cracked during the manufacturing process. When D L / D S is less than 7, the number of primary particles in the secondary particles decreases, the formed grain boundaries also decrease, the contact area between the electrolyte and the cathode material is small, and the material capacity decreases.

[0031] According to some embodiments of the present invention, the average particle size D of the primary particlesS and the size D of the average particle of the secondary particles L is measured by a scanning electron microscope (SEM), the particle size can be obtained by any graphical analysis software or manual measurement, and the data statistical results are obtained by any statistical software.

[0032] According to some embodiments of the present invention, the grain boundaries of the primary particles and the surfaces of the secondary particles are rich in Co. Preferably, when the content of Co for coating in the quasi-aggregated multi-component cathode material is the same, D L / D S The larger the value is, the lower the Co content at the grain boundaries of the primary particles is, and the higher the Co content on the surface of the secondary particles is, the smaller the D L / D S becomes smaller, and the higher the Co content at the grain boundaries of the primary particles is, the lower the Co content on the surface of the secondary particles is.

[0033] According to some embodiments of the present invention, preferably, the BET specific surface area of the quasi-aggregated multi-component cathode material is 0.1 - 0.4 m 2 / g, preferably 0.2 - 0.3 m 2 / g. The BET specific surface area of the quasi-aggregated multi-component cathode material is obtained by testing with a Tristar 3020 model specific surface area meter of Micromeritics.

[0034] According to some embodiments of the present invention, preferably, the full width at half maximum FWHM of the characteristic peak of the XRD test (104) of the quasi-aggregated multi-component cathode material (104) has a value range of 0.19 - 0.23, preferably 0.2 - 0.22. The full width at half maximum FWHM of the quasi-aggregated multi-component cathode material (104) is obtained by testing with a Smart Lab 9KW model X-ray diffractometer of Rigaku Corporation, and the full width at half maximum FWHM (104) specifically refers to the full width at half maximum of the (104) crystal plane of the quasi-aggregated multi-component cathode material, and the above value range indicates that the performance characterized by the XRD of the quasi-aggregated multi-component cathode material has the properties of a single crystal.

[0035] According to some embodiments of the present invention, preferably, the D of the agglomerated multi-component cathode material 50 is 5-15 μm, preferably 7-13 μm. The D of the agglomerated multi-component cathode material 50 is obtained by a test with a laser particle size distribution analyzer.

[0036] The second aspect of the present invention provides a method for manufacturing an agglomerated multi-component cathode material, and the manufacturing method includes: (1) Mixing a nickel source, a first cobalt source, a manganese source, a complexing agent, and a precipitant to perform a coprecipitation reaction to obtain a slurry, and then sequentially aging, compression filtering, washing, and drying the slurry to obtain a nickel cobalt manganese ternary precursor; (2) Mixing the nickel cobalt manganese ternary precursor and a lithium source to perform a first high-temperature sintering, and sequentially performing pulverization and sieving treatments to obtain an agglomerated cathode material process product; (3) Mixing the agglomerated cathode material process product and a second cobalt source to perform a second high-temperature sintering, and sequentially performing pulverization and sieving treatments to obtain an agglomerated multi-component cathode material.

[0037] It should be noted here that, in the present invention, for the purpose of distinction, the cobalt introduced from the first cobalt source is represented by Co 1 , and the cobalt introduced from the second cobalt source is represented by Co 2 .

[0038] According to some embodiments of the present invention, in step (1), the pH value of the coprecipitation reaction is 10-13. The higher the pH value of the coprecipitation reaction, the finer the obtained primary fibers, the larger the BET of the precursor, the easier it is to fuse during subsequent sintering, and the easier it is to form a cathode material with large primary particles. On the contrary, when the pH value of the coprecipitation reaction is low, the obtained primary fibers are thick, the BET of the precursor is small, it is difficult to fuse during subsequent sintering, and it is easy to form a cathode material with small primary particles.

[0039] According to some embodiments of the present invention, preferably, in step (1), the BET of the nickel cobalt manganese ternary precursor is 7-14 m 2 / g.

[0040] According to some embodiments of the present invention, preferably, in step (1), the conditions of the coprecipitation reaction further include that the temperature is 40-80 °C, the time is 5-40 h, and the rotation speed is 300-900 rpm.

[0041] According to some embodiments of the present invention, preferably, in step (1), the D 50 of the nickel cobalt manganese ternary precursor is 5-15 μm, preferably 7-13 μm.

[0042] According to some embodiments of the present invention, preferably, in step (1), the nickel source, the first cobalt source, and the manganese source are each independently selected from at least one of sulfates, chlorides, nitrates, and acetates. For example, the nickel source can be selected from at least one of nickel sulfate, nickel chloride, nickel nitrate, and nickel acetate, the first cobalt source can be selected from at least one of cobalt sulfate, cobalt chloride, cobalt nitrate, and cobalt acetate, and the manganese source can be selected from at least one of manganese sulfate, manganese chloride, manganese nitrate, and manganese acetate.

[0043] According to some embodiments of the present invention, preferably, in step (1), the mixing step includes a step of introducing a mixed salt aqueous solution containing the nickel source, the first cobalt source, and the manganese source, the complexing agent, and the precipitating agent into the reaction kettle in a co-current manner. More preferably, the concentration of the mixed salt aqueous solution is 2-3 mol / L. The mixed salt aqueous solution may be commercially available or prepared according to conventional methods in this field, and is not particularly limited thereto. Even more preferably, the mixing is carried out under the protection of an inert gas.

[0044] According to some embodiments of the present invention, in step (1), the precipitant may be a precipitant applicable to the production of nickel-cobalt-manganese ternary precursors known in the art, and is not particularly limited thereto. To a certain extent, the object of the present invention can be achieved. Preferably, the precipitant is selected from sodium hydroxide and / or potassium hydroxide. More preferably, the precipitant is provided in the form of an aqueous solution of the precipitant, and the concentration of the aqueous solution of the precipitant is 5-10 mol / L.

[0045] According to some embodiments of the present invention, in step (1), the complexing agent may be a complexing agent applicable to the production of nickel-cobalt-manganese ternary precursors known in the art, and is not particularly limited thereto. To a certain extent, the object of the present invention can be achieved. Preferably, the complexing agent can be selected from at least one of aqueous ammonia, disodium ethylenediaminetetraacetate, ammonium nitrate, ammonium chloride, and ammonium sulfate. More preferably, the complexing agent is provided in the form of an aqueous solution of the complexing agent, and the mass fraction of the aqueous solution of the complexing agent is 20-30%.

[0046] According to some embodiments of the present invention, in step (1), the usage amounts of the precipitant and the complexing agent are not particularly limited, as long as the usage amount of the precipitant and the usage amount of the complexing agent enable the coprecipitation reaction to meet the growth requirements of the precursor.

[0047] According to some embodiments of the present invention, in step (1), the aging, pressure filtration, washing, and drying can be performed by ordinary methods well known to those skilled in the art, and are not particularly limited thereto.

[0048] According to some embodiments of the present invention, preferably, in step (2), the temperature of the first high-temperature sintering is T, and the value range of T satisfies formula II,

Number

Number

[0049] According to some embodiments of the present invention, preferably, in step (2), when the temperature of the first high-temperature sintering is high, D L / D S becomes small, and when the temperature of the first high-temperature sintering is low, D L / D S becomes large.

[0050] According to some embodiments of the present invention, preferably, in step (2), the conditions of the first high-temperature sintering further include that the time is 10 - 30 h and the sintering atmosphere is provided by an oxygen-containing gas. Preferably, the oxygen content in the oxygen-containing gas is 1 - 100 vol%.

[0051] According to some embodiments of the present invention, preferably, in step (2), D of the quasi-aggregated cathode material process product 50 is 5 - 15 μm, preferably 7 - 13 μm.

[0052] According to some embodiments of the present invention, D of the nickel-cobalt-manganese ternary precursor 50 and D of the quasi-aggregated cathode material process product 50 are obtained by a laser particle size distribution analyzer test.

[0053] According to some embodiments of the present invention, preferably, in step (2), in a stoichiometric ratio, the usage amount of the lithium source satisfies 0.9 ≦ [n(Li)] / [n(Ni) + n(Co 1 ) + n(Mn)] ≦ 1.1, and preferably, 1.02 ≦ [n(Li)] / [n(Ni) + n(Co 1 ) + n(Mn)] ≦ 1.06.

[0054] According to some embodiments of the present invention, in step (2), the lithium source may be a lithium source applicable to the production of cathode materials known in the art, and is not particularly limited thereto, and to a certain extent, the object of the present invention can be achieved. Preferably, the lithium source is selected from at least one of lithium carbonate, lithium hydroxide, lithium oxide, and lithium acetate.

[0055] According to some embodiments of the present invention, in step (2), the pulverization and sieving processes can be performed by a conventional method well known to those skilled in the art, and are not particularly limited thereto, and D 50 It is only necessary to obtain an agglomerated cathode material process product that meets the above requirements.

[0056] According to some embodiments of the present invention, preferably, in step (3), the conditions for the second high-temperature sintering include that the temperature is 200 - 1000 °C, the time is 5 - 20 h, and the sintering atmosphere is provided by an oxygen-containing gas. Preferably, the oxygen content in the oxygen-containing gas is 1 - 100 vol%.

[0057] According to some embodiments of the present invention, preferably, in step (3), the second cobalt source is at least one of cobalt oxide, cobalt(III) hydroxide, cobalt oxyhydroxide, cobalt fluoride, cobalt(II) hydroxide, tricobalt tetraoxide, cobalt carbonate, and cobalt acetate, preferably at least one of cobalt oxide, cobalt(III) hydroxide, tricobalt tetraoxide, cobalt oxyhydroxide, and cobalt(II) hydroxide. Adopting the above preferred embodiments is advantageous for controlling surface residual alkali by facilitating uniform coating.

[0058] According to some embodiments of the present invention, preferably, in step (3), in terms of stoichiometric ratio, the usage amount of the second cobalt source is 0.005 ≦ [n(Co 2 )] / [n(Ni) + n(Co 1 ) + n(Mn)] ≦ 0.1, preferably 0.01 ≦ [n(Co 2)] / [n(Ni) + n(Co 1 ) + n(Mn)] ≤ 0.06 is satisfied.

[0059] According to some embodiments of the present invention, the usage amounts of the first cobalt source and the second cobalt source are such that the total cobalt content in the agglomerated multi-component cathode material satisfies n(Ni):n(Co):n(Mn) = x:y:z, where n(Co) = n(Co 1 ) + n(Co 2 ). The values taken by x, y, and z can be defined and selected with reference to the above, and the description is omitted here.

[0060] According to some embodiments of the present invention, preferably, in step (3), the D 50 of the agglomerated multi-component cathode material is 5 - 15 μm, preferably 7 - 13 μm.

[0061] According to some embodiments of the present invention, in step (3), the pulverization and sieving processes can be carried out by a conventional method well known to those skilled in the art, and are not particularly limited thereto. It is only necessary to obtain an agglomerated multi-component cathode material in which D 50 satisfies the above requirements.

[0062] According to some embodiments of the present invention, preferably, in step (1), the raw materials for mixing further include an additive.

[0063] According to some embodiments of the present invention, preferably, in step (2), the raw materials for mixing further include a dopant.

[0064] According to some embodiments of the present invention, preferably, in step (3), the raw materials for mixing further include a coating agent.

[0065] According to some embodiments of the present invention, the additive, the dopant, and the coating agent may be the same or different, and each is independently selected from at least one of M-containing compounds, preferably oxides, fluorides, hydroxides, oxyhydroxides, carbonates, nitrates, sulfates, and acetates containing M.

[0066] According to some embodiments of the present invention, preferably, the dopant is selected from at least one of MgO, WO3, TiO2, Nb2O5, and Al2O3.

[0067] According to some embodiments of the present invention, preferably, the coating agent is selected from at least one of V2O5, La2O3, SiO2, and B2O3.

[0068] According to some embodiments of the present invention, preferably, the amount of the additive used is such that the molar fraction of the additive in terms of M element occupying the total molar amount of Ni, Co, and Mn is 0.01% - 3%.

[0069] According to some embodiments of the present invention, preferably, the amount of the dopant used is such that the molar fraction of the dopant in terms of M element occupying the total molar amount of Ni, Co, and Mn is 0.01% - 3%.

[0070] According to some embodiments of the present invention, preferably, the amount of the coating agent used is such that the molar fraction of the coating agent in terms of M element occupying the total molar amount of Ni, Co, and Mn is 0.01% - 3%.

[0071] According to some embodiments of the present invention, the total amount of the additive, the dopant, and the coating agent used satisfies n(Ni):n(Co):n(Mn):n(M)=x:y:z:b in the obtained multi-component cathode material, where the values taken by x, y, z, and b can be defined and selected with reference to the above, and the description is omitted here.

[0072] According to some embodiments of the present invention, the agglomerated multi-component cathode material obtained by the manufacturing method has a structure represented by Formula I, Li a Ni x Co y Mn z M b O2 Formula I In Formula I, 0.9 ≦ a ≦ 1.1, 0.5 ≦ x < 1, 0 < y < 0.5, 0 < z < 0.5, 0 ≦ b < 0.05, and M is at least one of V, Ta, Cr, La, Al, Ce, Er, Ho, Y, Mg, Sr, Ba, Ra, Zr, Fe, Ca, Zn, B, W, Nb, Cd, Pb, Si, Mo, Cu, Sr, and Ti, The multi-component cathode material is secondary particles in which primary particles are aggregated. The primary particles are spherical or quasi-spherical, and the average particle size D of the primary particles S is 0.9 - 2.4 μm, the average particle size D of the secondary particles L is 5 - 15 μm, and the range of the value of D L / D S is 5 - 16.

[0073] A third aspect of the present invention provides an agglomerated multi-component cathode material obtained by the manufacturing method described in the second aspect.

[0074] A fourth aspect of the present invention provides the use of the agglomerated multi-component cathode material described in the first aspect or the third aspect, or the manufacturing method described in the second aspect in a lithium-ion battery.

[0075] A fifth aspect of the present invention provides a lithium-ion battery including the agglomerated multi-component cathode material described in the first aspect or the third aspect.

[0076] Hereinafter, the present invention will be described in detail by way of examples. In the following examples and comparative examples, all raw materials are commercially available products unless otherwise specified.

[0077] Unless otherwise specified, room temperature refers to 25 ± 2°C.

[0078] In the following examples and comparative examples, the relevant parameters are obtained by the tests of the following methods. (1) Morphology test: Obtained by the test of the scanning electron microscope of model S-4800 of Hitachi, Japan. (2) BET test: Obtained by the test of the specific surface area meter of model Tristar 3020 of Micromeritics. (3) XRD test: Obtained by the test of the X-ray diffractometer of model Smart Lab 9KW of Rigaku, Japan. (4) D 50 Particle size test: Obtained by the test of the laser particle size distribution analyzer of model Hydro 2000mu of Marvern. (5) Electrochemical performance test: In the following examples and comparative examples, the electrochemical performance of the multi-component cathode material is tested using a 2025 type button cell.

[0079] The manufacturing process of the 2025 type button cell is specifically as follows.

[0080] Pole piece manufacturing: The multi-component cathode material, acetylene black, and polyvinylidene fluoride (PVDF) are sufficiently mixed with an appropriate amount of N-methylpyrrolidone (NMP) at a mass ratio of 95:3:2 to form a uniform slurry. The slurry is coated on an aluminum foil and dried at 120 °C for 12 h, and then pressed and formed at a pressure of 100 MPa to manufacture a positive electrode pole piece with a diameter of 12 mm and a thickness of 120 μm. The loading amount of the multi-component cathode material is 15-16 mg / cm 2 .

[0081] Battery assembly: In a gas glove box filled with argon gas with both the water content and the oxygen content less than 5 ppm, the positive electrode pole piece, separator, negative electrode pole piece, and electrolyte are assembled into a 2025 type button cell and then left standing for 6 h. The negative electrode pole piece uses a lithium metal sheet with a diameter of 17 mm and a thickness of 1 mm. The separator uses a polyethylene porous film (Celgard 2325) with a thickness of 25 μm. The electrolyte uses an equal volume mixture of 1 mol / L LiPF6, ethylene carbonate (EC), and diethyl carbonate (DEC).

[0082] Electrochemical performance test: In the following examples and comparative examples, an electrochemical performance test was carried out on a 2025-type button battery using a deep-sensing Xinwei'er battery test system, and the charge-discharge current density of 0.1C was 200 mA / g.

[0083] The charge-discharge voltage range was controlled to 3 - 4.3V. At room temperature, the button battery was charged and discharged at 0.1C to evaluate the initial charge-discharge specific capacity and the initial charge-discharge efficiency of the multi-component cathode material.

[0084] Cycle performance test: The charge-discharge voltage range was controlled to 3.0 - 4.3V. At a constant temperature of 45°C, the button battery was charged and discharged at 0.1C for 2 cycles, and then charged and discharged at 1C for 80 cycles to evaluate the high-temperature capacity retention rate of the multi-component cathode material.

[0085] Rate performance test: The charge-discharge voltage range was controlled to 3.0 - 4.3V. At room temperature, the button battery was charged and discharged at 0.1C for 2 cycles, and then charged and discharged at 0.2C, 0.33C, 0.5C, and 1C for 1 cycle each. The rate performance of the multi-component cathode material was evaluated by the ratio of the initial discharge specific capacity at 0.1C to the discharge specific capacity at 1C. The initial discharge specific capacity at 0.1C is the discharge specific capacity of the first cycle of the button battery, and the discharge specific capacity at 1C is the discharge specific capacity of the sixth cycle of the button battery.

[0086] Example 1 (1) A nickel source, a first cobalt source, a manganese source, a complexing agent, and a precipitating agent were mixed for coprecipitation reaction to obtain a slurry. The slurry was aged, compression-filtered, washed, and dried in sequence to obtain a nickel-cobalt-manganese ternary precursor. The nickel source was nickel sulfate, the first cobalt source was cobalt sulfate, the manganese source was manganese sulfate, the complexing agent was provided in the form of an aqueous solution of the complexing agent, which was ammonia water with a mass fraction of 25%, and the precipitating agent was provided in the form of an aqueous solution of the precipitating agent, which was an 8 mol / L NaOH aqueous solution. The mixing step specifically involves introducing an aqueous solution containing the nickel source, the first cobalt source, and the manganese source, an aqueous complexing agent solution, and an aqueous precipitating agent solution into a reaction kettle in a co-current manner under the protection of nitrogen gas. Here, the molar ratio of Ni:Co 1 :Mn is shown in Table 1, The conditions for the coprecipitation reaction include a temperature of 60 °C, a time of 20 h, and a rotation speed of 800 rpm. The pH value of the coprecipitation reaction is shown in Table 1, The chemical formula composition, BET, and D of the obtained nickel-cobalt-manganese ternary precursor 50 are shown in Table 2.

[0087] (2) Mix the nickel-cobalt-manganese ternary precursor and a lithium source as a dopant and perform the first high-temperature sintering. Then, perform pulverization and sieving processes sequentially to obtain an agglomerated cathode material process product. The lithium source is lithium hydroxide. The types of dopants and the molar ratios of the usage amounts of each raw material are shown in Table 1. The conditions for the first high-temperature sintering include a time of 18 h and a sintering atmosphere provided by oxygen. The temperature of the first high-temperature sintering is shown in Table 1. Before performing the pulverization and sieving processes, the product of the first high-temperature sintering is naturally cooled to room temperature. The chemical formula composition and D of the obtained agglomerated cathode material process product 50 are shown in Table 2.

[0088] (3) Mix the agglomerated cathode material process product and a second cobalt source and perform the second high-temperature sintering. Then, perform pulverization and sieving processes sequentially to obtain an agglomerated multi-component cathode material. The types of the second cobalt source and the molar ratios of the usage amounts of each raw material are shown in Table 1. The conditions for the second high-temperature sintering include a temperature of 720 °C, a time of 10 h, and a sintering atmosphere provided by oxygen. Before performing the pulverization and sieving processes, the product of the second high-temperature sintering is naturally cooled to room temperature. The chemical formula composition and D of the obtained agglomerated multi-component cathode material 50 are shown in Table 2.

[0089] Examples 2 - 5 According to the method of Example 1, the raw materials and process parameters used were different, specifically shown in Table 1. Otherwise, in the same manner as Example 1, an aggregated multi-component cathode material was manufactured. The chemical formula compositions and characteristic parameter test data of each product are shown in Table 2.

[0090] Comparative Example 1 According to the method of Example 1, in step (1), the pH value of the coprecipitation reaction was 11.2, and in step (2), the temperature of the first high-temperature sintering was 790 °C. Otherwise, in the same manner as Example 1, a cathode material was manufactured. The chemical formula compositions and characteristic parameter test data of each product are shown in Table 2.

[0091] Comparative Example 2 According to the method of Example 1, in step (1), the pH value of the coprecipitation reaction was 13.2, and in step (2), the temperature of the first high-temperature sintering was 970 °C. Otherwise, in the same manner as Example 1, a cathode material was manufactured. The chemical formula compositions and characteristic parameter test data of each product are shown in Table 2.

[0092] Comparative Example 3 According to the method of Example 1, step (3) was not carried out. Otherwise, in the same manner as Example 1, the aggregated cathode material process product was directly used as the cathode material. The chemical formula compositions and characteristic parameter test data of each product are shown in Table 2.

[0093]

Table 1

[0094] Test Example (1) Morphology Test The present invention is a scanning electron microscope (SEM) image of the positive electrode materials manufactured in the above-mentioned examples and comparative examples. FIG. 1 is an SEM diagram of the aggregated multi-component positive electrode material obtained in Example 1 of the present invention. FIG. 2 is an SEM diagram of the positive electrode material obtained in Comparative Example 1 of the present invention. FIG. 3 is an SEM diagram of the positive electrode material obtained in Comparative Example 2 of the present invention. As can be seen from the figures, the primary particles in the positive electrode material obtained in Example 1 are larger than those in the aggregated Comparative Example 1 and smaller than those in the single crystal type Comparative Example 2. The gaps between the primary particles in the positive electrode material obtained in Example 1 are large, and the secondary particles are round spherical. (2) Physical property test The present invention tests the D 50 , BET, XRD (half-value width FWHM (104) ), the average particle size D of the primary particles S and the average particle size D of the secondary particles L of the positive electrode materials manufactured in the above-mentioned examples and comparative examples, and shows the specific test results in Table 2.

[0095]

Table 2-1

[0096]

Table 2-2

[0097] As can be seen from the results of Table 1 and Table 2, in the manufacturing process of the aggregated multi-component positive electrode material, when the temperature of the first sintering is increased, the FWHM (104) of the positive electrode material becomes smaller. When the temperature increases, the average size of the primary particles increases. When the primary particles grow to a certain size, they separate from each other and become independent particles.

[0098] D of the positive electrode material of Comparative Example 1 L / D S is large and it is an aggregated material. Comparative Example 2 is a single crystal type material. The FWHM of the quasi-aggregated multi-component positive electrode material of the present invention (104) is between the single crystal type material and the aggregated material and is close to the single crystal type material. (3) Composition test The present invention tests the Ni, Co, and Mn compositions at the center of the primary particles, the grain boundaries of the primary particles, and the surface of the secondary particles of the positive electrode materials manufactured in the above Examples and Comparative Examples, obtains the difference in Co content, and shows the specific test results in Table 3. The Ni, Co, and Mn compositions are the average results of multiple-point tests.

[0099]

Table 3

[0100] As can be seen from Table 3, when the primary particles in the positive electrode material are large, the grain boundaries between the primary particles are large, and a large amount of Co enters the grain boundaries. When the primary particles are small, it is difficult for Co to enter the grain boundaries, and most of it is coated on the surface of the secondary particles of the material.

[0101] (4) Electrochemical performance test The present invention tests the electrochemical performance of the positive electrode materials manufactured in the above Examples and Comparative Examples, including the initial discharge specific capacity at 0.1C, the 1C discharge specific capacity, the rate performance, and the cycle performance, shows the specific test results in Table 4, and the test temperature of the discharge specific capacity at a 1C rate is 25°C.

[0102]

Table 4

[0103] As can be seen from Table 4, Example 2 has a lower sintering temperature than Example 1, smaller primary particles, less grain boundary Co than Example 1, more external Co, and worse material cycling. Example 3 has a higher sintering temperature than Example 1, larger primary particles, more grain boundary Co than Example 1, less external Co, and a slightly lower material volume rate. Example 4 has less coated Co than Example 1, less grain boundary and surface Co, a lower material rate, and poor cycling. Comparative Example 1 is an agglomerated material with small primary particles, a compact structure, and Co unable to enter the interior of secondary particles along the grain boundaries, with very little grain boundary Co, a low material volume rate, and poor cycling. Comparative Example 2 is a single crystal type material with large primary particles, the primary particles being separated from each other and independent, and Co being rich on the surface of the material, with a low material volume rate. Comparative Example 3 has no coated Co, a low material rate, and poor cycling.

[0104] The above has described the preferred embodiments of the present invention in detail, but the present invention is not limited thereto. Within the technical concept scope of the present invention, multiple simple modifications are possible to the technical solution means of the present invention, including combinations of these simple modifications with the combination of each technical feature in any other appropriate manner, and these simple modifications and combinations are similarly regarded as the content disclosed in the present invention and all belong to the protection scope of the present invention.

[0105] (Cross - reference to related applications) This application claims the benefit of Chinese Patent Application No. 202211352231.X, filed on October 31, 2022, the content of which is incorporated herein by reference.

Claims

1. A class-aggregated multi-component cathode material, wherein the multi-component cathode material has a structure represented by Formula I, Li ａ Ni ｘ Co ｙ Mn ｚ M ｂ O ２ Formula I In Formula I, 0.9 ≦ a ≦ 1.1, 0.5 ≦ x < 1, 0 < y < 0.5, 0 < z < 0.5, 0 ≦ b < 0.05, and M is at least one of V, Ta, Cr, La, Al, Ce, Er, Ho, Y, Mg, Sr, Ba, Ra, Zr, Fe, Ca, Zn, B, W, Nb, Cd, Pb, Si, Mo, Cu, Sr, and Ti, The multi-component cathode material is secondary particles in which primary particles aggregate, the primary particles are spherical or quasi-spherical, and the average particle size D of the primary particles Ｓ is 0.9 - 2.4 μm, and the average particle size D of the secondary particles Ｌ is 5 - 15 μm, and the value range of D Ｌ / D Ｓ is 5 - 16, and the aggregated multi-component cathode material is characterized by this.

2. It is rich in Co at the grain boundaries of the primary particles and on the surface of the secondary particles. Let the Co molar content at the center of the primary particles be K1, the Co molar content at the grain boundaries of the primary particles be K2, and the Co molar content on the surface of the secondary particles be K3. K2 - K1 ≧ 0.5%, preferably, K2 - K1 ≧ 1%, and K3 - K1 ≧ 1.5%, preferably, K3 - K1 ≧ 3%. The class-aggregated multi-component cathode material according to Claim 1.

3. In Formula I, 1 ≦ a ≦ 1.1, 0.0005 ≦ b ≦ 0.01, and / or M is at least one of Mg, W, V, Ti, La, Nb, Si, Al, and B, and / or, the size D of the average particle of the primary particles Ｓ is 1.2 - 1.8 μm, and / or, the size D of the average particle of the secondary particles Ｌ is 7 - 13 μm, and / or, D Ｌ / D Ｓ The range of the value taken by the same is 7 - 12. The aggregated multi-component cathode material according to claim 1 or 2.

4. The BET specific surface area of the lectin-like multi-component cathode material is 0.1 - 0.4 m ２ / g, preferably 0.2 - 0.3 m ２ / g, and and / or, the full width at half maximum FWHM of the characteristic peak of the XRD test (104) of the pseudo-agglomerated multi-component cathode material （１０４） the value range taken is 0.19 - 0.23, preferably 0.2 - 0.22, and and / or, D of the agglomerated multi-component cathode material ５０ is 5 - 15 μm, preferably 7 - 13 μm, the agglomerated multi-component cathode material according to claim 1 or 2.

5. A method for manufacturing a class-aggregated multi-component cathode material, wherein the manufacturing method includes (1) mixing a nickel source, a first cobalt source, a manganese source, a complexing agent, and a precipitating agent to carry out a coprecipitation reaction to obtain a slurry, and then successively aging, compression filtering, washing, and drying the slurry to obtain a nickel-cobalt-manganese ternary precursor; (2) mixing the nickel-cobalt-manganese ternary precursor and a lithium source to carry out a first high-temperature sintering, and successively performing pulverization and sieving treatments to obtain a class-aggregated cathode material process product; (3) mixing the class-aggregated cathode material process product and a second cobalt source to carry out a second high-temperature sintering, and successively performing pulverization and sieving treatments to obtain a class-aggregated multi-component cathode material. The method for manufacturing a class-aggregated multi-component cathode material is characterized by including the above steps.

6. In step (1), the pH value of the coprecipitation reaction is 10 - 13, and / or the temperature of the coprecipitation reaction is 40 - 80 °C, the time is 5 - 40 h, and the rotation speed is 300 - 900 rpm, And / or, the BET specific surface area of the nickel cobalt manganese ternary precursor is 7-14 m ２ / g, and and / or, D of the nickel cobalt manganese ternary precursor ５０ is 5-15 μm, preferably 7-13 μm, and the manufacturing method according to claim 5.

7. In step (2), let the temperature of the first high-temperature sintering be T, and the value range of T satisfies Formula II, 【Number 1】 Preferably, the value range of T satisfies Formula III, 【Number 2】 Here, C Ｎｉ is the molar percentage of nickel element in the mixture composed of the nickel source, the first cobalt source, and the manganese source, And / or, the time of the first high-temperature sintering is 10 - 30 h, and the sintering atmosphere is provided by an oxygen-containing gas. and / or, D of the pseudo-aggregated positive electrode material processed product ５０ is 5 - 15 μm, preferably 7 - 13 μm, And / or, in a stoichiometric ratio, the usage amount of the lithium source satisfies 0.9 ≦ [n(Li)] / [n(Ni) + n(Co １ ) + n(Mn)] ≦ 1.1, preferably 1.02 ≦ [n(Li)] / [n(Ni) + n(Co １ ) + n(Mn)] ≦ 1.

06. The manufacturing method according to claim 5.

8. In step (3), the conditions of the second high-temperature sintering include that the temperature is 200 - 1000 °C, the time is 5 - 20 h, and the sintering atmosphere is provided by an oxygen-containing gas. And / or, the second cobalt source is at least one selected from cobalt oxide, cobalt(III) hydroxide, cobalt oxyhydroxide, cobalt fluoride, cobalt(II) hydroxide, cobalt tetroxide, cobalt carbonate, and cobalt acetate, preferably at least one selected from cobalt oxide, cobalt(III) hydroxide, cobalt tetroxide, cobalt oxyhydroxide, and cobalt(II) hydroxide. And / or, in a stoichiometric ratio, the usage amount of the second cobalt source satisfies 0.005 ≦ [n(Co ２ )] / [n(Ni) + n(Co １ ) + n(Mn)] ≦ 0.1, preferably 0.01 ≦ [n(Co ２ )] / [n(Ni) + n(Co １ ) + n(Mn)] ≦ 0.

06. The manufacturing method according to any one of claims 5 - 7.

9. In step (1), the mixed raw materials further include an additive, and / or in step (2), the mixed raw materials further include a dopant, and / or in step (3), the mixed raw materials further include a coating agent. The additive, the dopant, and the coating agent may be the same or different, and each is independently selected from at least one of M-containing compounds, preferably oxides, fluorides, hydroxides, oxyhydroxides, carbonates, nitrates, sulfates, and acetates containing M. Preferably, the dopant is selected from at least one of MgO, WO ３ , TiO ２ , Nb ２ O ５ and Al ２ O ３ , and / or the coating agent is selected from at least one of V ２ O ５ , La ２ O ３ , SiO ２ and B ２ O ３ . The manufacturing method according to any one of claims 5-8

10. A quasi-aggregated multi-component cathode material manufactured by the manufacturing method according to any one of claims 5 - 9.

11. Use in a lithium-ion battery of the quasi-aggregated multi-component cathode material according to any one of claims 1 - 4 or 10, or the manufacturing method according to claims 5 - 9.

12. A lithium-ion battery comprising the quasi-aggregated multi-component cathode material according to any one of claims 1 - 4 or 10.

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