Agglomerated multi-component positive electrode material, its manufacturing method, use, 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 in particular to agglomerated multi-component positive electrode material and a manufacturing method thereof, and a lithium ion battery. [Background technology]

[0002] In recent years, energy and environmental issues have received increasing attention, and the development of new energy vehicles around the world began with hybrids, then entered an era centered on batteries, with pure electric vehicles and plug-in hybrids becoming the mainstay of real policy support for new energy.

[0003] High safety and long driving time are the development trends of electric vehicles. To meet the increasing demands of electric vehicles, power lithium batteries need to have higher energy density and better cycle stability. In the lithium battery industry chain, the link with the largest market size and highest production value is the cathode material, and its performance determines the battery's energy density, lifespan, rate performance, etc., making the cathode material a core and important material for lithium batteries.

[0004] Ternary materials are characterized by high energy density, good cycle stability, and good safety. The mainstream ternary materials on the market today are agglomerated materials and monocrystalline materials. Agglomerated materials have good rate performance but somewhat poor cycle performance, while monocrystalline materials have good cycle performance but small particle size, low production efficiency, and somewhat poor rate performance.

[0005] To obtain a cathode material with high energy density and high structural stability, it is necessary to rationally design the material structure to achieve both energy density, rate performance, and cycle stability.

[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, 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.

[0009] The second aspect of the present invention provides a method for manufacturing an aggregated 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 precipitating agent to perform a coprecipitation reaction to obtain a slurry, and then sequentially aging, pressure 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 then sequentially performing pulverization and sieving treatments to obtain an aggregated cathode material process product; (3) Mixing the aggregated cathode material process product and a second cobalt source to perform a second high-temperature sintering, and then sequentially performing pulverization and sieving treatments to obtain an aggregated multi-component cathode material.

[0010] The third aspect of the present invention provides an aggregated 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 aggregated 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] A fifth aspect of the present invention provides a lithium ion battery comprising the near-agglomerated multi-component positive electrode material according to the first or third aspect. [Effects of the Invention]

[0013] According to the above technical solutions, the present invention has the following advantages:

[0014] 1. The particle size of the primary particles of the agglomerated ternary positive electrode material in the prior art is usually 0.2-0.6 μm. The agglomerated multi-component positive electrode material of the present invention is a secondary particle formed by agglomeration of primary particles, and the primary particles are spherical or near-spherical, are more closely stacked, have a stronger bonding force with each other, and have a higher compaction density. The formed secondary particles are also spherical or near-spherical. In the present invention, the morphological characteristics of the primary particles and secondary particles are advantageous for improving the energy density and cycle performance of the battery. The average particle size D of the primary particles is S is 0.9-2.4 μm, which is close to the size of single-crystal ternary positive electrode materials. Conventional agglomerated ternary positive electrode materials are prone to cracking during the electrode plate preparation process, and the primary particles are prone to separation during cycling due to particle expansion and contraction, destroying the material structure and reducing electrical performance. The near-agglomerated multi-component positive electrode material of the present invention can compensate for the defects of agglomerated materials, has stronger pressure resistance, and even if separation of primary particles occurs during cracking and cycling, the performance of the separated primary particles is still similar to that of single-crystalline materials, ensuring the stability of the electrical performance of the positive electrode material during cycling.

[0015] 2. In the near-agglomerated multi-component positive electrode material according to the present invention, the average particle size D of the secondary particles is L is 5-15 μm, which is close to the aggregated material and larger than the primary particle of the single crystal material. After the electrode pieces are produced, the bonding between the particles of the single crystal material is tighter, the rate performance is better, less conductive agent and binder are required, which is favorable for increasing the proportion of active material, and the compaction density of the electrode pieces is higher, which can improve the energy density of the battery.

[0016] 3. In the near-agglomerated multi-component positive electrode material of the present invention, the grain boundaries of the primary particles and the surfaces of the secondary particles are rich in Co, and the molar content of Co at the centers of the primary particles is K1, the molar content of Co at the grain boundaries of the primary particles is K2, and the molar content of Co at the surfaces of the secondary particles is K3, where K2-K1≧0.5% and K3-K1≧1.5%. Because the primary particles of the multi-component positive electrode material of the present invention are large, the gaps at the grain boundaries between the primary particles are large. After the processed product of the agglomerated positive electrode material is coated with a highly ductile cobalt-containing compound and then sintered at high temperature, the cobalt element is not only coated on the surfaces of the secondary particles, but also penetrates into the secondary particles along the grain boundaries of the primary particles and agglomerates at the interfaces between the primary particles, thereby achieving the purpose of simultaneously coating the primary particles and the secondary particles with cobalt element. During the electrode piece preparation and cycling process of the obtained multi-component positive electrode material, even if the secondary particles are crushed or the electrolyte reaches the surfaces of the primary particles through the grain boundaries, the exposed surfaces of the primary particles are still protected by the coating layer, thereby improving the structural stability of the material, inhibiting electrolyte erosion, and improving cycling stability and safety. [Brief explanation of the drawings]

[0017] [Figure 1] FIG. 2 is an SEM image of the aggregated multi-component positive electrode material obtained in Example 1 of the present invention. [Figure 2] FIG. 2 is an SEM image of the positive electrode material obtained in Comparative Example 1 of the present invention. [Figure 3] FIG. 2 is an SEM image of the positive electrode material obtained in Comparative Example 2 of the present invention. [Figure 4] 1C cycle performance chart of the positive electrode materials obtained in Example 1 and Comparative Examples 1 and 2 of the present invention, where the test temperature is 45° C. and the voltage range is 3.0-4.3V. DETAILED DESCRIPTION OF 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 there is a clear indication, "first" and "second" do not represent the order before and after, nor are they for limiting individual materials or operations, but are only for distinguishing individual materials or operations. For example, "first cobalt source" and "second cobalt source" in "first cobalt source" and "second cobalt source" only distinguish to indicate that this is not the same cobalt source, and "first high-temperature sintering" and "second high-temperature sintering" in "first high-temperature sintering" and "second high-temperature sintering" only distinguish to indicate that they are not the same high-temperature sintering operation.

[0020] The first aspect of the present invention provides an 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, the near-agglomerated multi-component positive electrode material is prepared by controlling the sizes of primary particles and secondary particles, and L / D S By combining the range of values ​​taken by , the formed multi-component positive electrode material is quasi-agglomerated, which combines the excellent performance of both single crystal materials and aggregated materials, and can achieve high energy density, rate performance, and cycle stability of the positive electrode material.

[0022] According to some embodiments of the present invention, the near-agglomerated multi-component positive electrode material preferably has a spherical or near-spherical morphology, and the morphology of the near-agglomerated multi-component positive electrode material is characterized by scanning electron microscopy (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 enriched in Co, and the molar Co content at the centers of the primary particles is K1, the molar Co content at the grain boundaries of the primary particles is K2, and the molar Co content at the surfaces of the secondary particles is K3, where K2-K1≧0.5%, preferably K2-K1≧1%, and K3-K1≧1.5%, preferably K3-K1≧3%. The "center" in the center of the primary particles does not refer to the exact center, but refers to the main portion excluding the grain boundaries of the primary particles and the surfaces of the secondary particles.

[0024] The adoption of the above preferred embodiment is advantageous in that a uniform coating layer is formed on the grain boundaries and surfaces of secondary particles, thereby increasing the mobility of lithium ions and suppressing the erosion of the electrolyte, thereby 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 The range of values ​​that can be taken is 7-12.

[0030] Adopting the above preferred embodiment, D S is set to 1.2-1.8 μm. If Ds is larger than 1.8 μm, the primary particles will be large, the material rate performance will be low, and the product performance may approach that of a single crystal material. If Ds is smaller than 1.2 μm, the primary particles will be small, the structural stability will be poor, the cycle performance will be low, and the product performance may approach that of an agglomerated material. Therefore, adopting the above preferred embodiment, D L Set the value to 7-13 μm and D L If the diameter is larger than 13 μm, the secondary particles become large, the mobility of lithium ions becomes low, the velocity becomes poor, and D L If D is smaller than 7 μm, the secondary particles become small, the compaction density is low, and this leads to a decrease in energy density and deterioration of cycle. L / D S Set the range of values ​​to 7-12, and D L / D S If the value is greater than 12, the number of primary particles in the secondary particles will increase, forming many grain boundaries, which will reduce the pressure resistance of the material and make the product performance closer to that of agglomerates. The pole pieces will be easily crushed during the manufacturing process, and D L / D S If is less than 7, the number of primary particles in the secondary particles will be small, the number of formed grain boundaries will also be small, the contact area between the electrolyte and the positive electrode material will be small, and the material capacity will decrease.

[0031] According to some embodiments of the present invention, the average particle size D of the primary particlesS and the average particle size of the secondary particles D L is measured by scanning electron microscope (SEM), the size of the particles can be obtained by any graphical analysis software or manual measurement, and the data statistical results can be 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 coating in the near-agglomerated multi-component positive electrode material is the same, D L / D S The larger the Co content at the grain boundary of the primary particles, the lower the Co content at the surface of the secondary particles. L / D S The Co content at the surface of the secondary particles decreases as the Co content at the grain boundaries of the primary particles increases.

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

[0034] According to some embodiments of the present invention, preferably, the full width at half maximum (FWHM) of a characteristic peak in the XRD test (104) of the near-agglomerated multi-component positive electrode material (104) The range of values ​​taken by the FWHM of the near-agglomerated multi-component positive electrode material is 0.19-0.23, and preferably 0.2-0.22. (104) is obtained by X-ray diffractometer test using Smart Lab 9KW model of Nippon Rigaku Co., Ltd., and FWHM (104) Specifically, the full width at half maximum of the (104) crystal plane of the near-agglomerated multi-component positive electrode material is in the above-mentioned value range, and the performance of the near-agglomerated multi-component positive electrode material characterized by XRD has the properties of a single crystal.

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

[0036] A second aspect of the present invention provides a method for producing a near-agglomerated multi-component positive electrode material, the method comprising: (1) mixing a nickel source, a first cobalt source, a manganese source, a complexing agent, and a precipitating agent to undergo a co-precipitation reaction to obtain a slurry, and then sequentially aging, compressing, filtering, washing, and drying the slurry to obtain a nickel-cobalt-manganese ternary precursor; (2) mixing the nickel-cobalt-manganese ternary precursor with a lithium source, performing a first high-temperature sintering process, and then performing a crushing and sieving process to obtain a processed product of agglomerated positive electrode material; (3) mixing the processed product of the near-agglomerated positive electrode material with a second cobalt source, and subjecting the mixture to second high-temperature sintering, followed by pulverizing and screening to obtain a near-agglomerated multi-component positive electrode material.

[0037] It is necessary to explain here that, in the present invention, for the purpose of distinction, the cobalt introduced from the first cobalt source is referred to as Co 1 and the cobalt introduced from the second cobalt source is denoted by Co 2 Shown in.

[0038] According to some embodiments of the present invention, in step (1), the pH value of the co-precipitation reaction is 10-13. The higher the pH value of the co-precipitation reaction, the thinner the resulting primary fibers are, the larger the BET of the precursor is, and the easier it is to fuse during subsequent sintering, making it easier to form a positive electrode material with large primary particles. Conversely, the lower the pH value of the co-precipitation reaction, the coarser the resulting primary fibers are, the smaller the BET of the precursor is, and the easier it is to fuse during subsequent sintering, making it easier to form a positive electrode 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 7-14m 2 / g.

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

[0041] According to some embodiments of the present invention, preferably, in step (1), D of the nickel-cobalt-manganese ternary precursor 50 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 may be selected from at least one of nickel sulfate, nickel chloride, nickel nitrate, and nickel acetate; the first cobalt source may be selected from at least one of cobalt sulfate, cobalt chloride, cobalt nitrate, and cobalt acetate; and the manganese source may 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, in step (1), the mixing step preferably includes a step of simultaneously feeding the mixed salt aqueous solution containing the nickel source, the first cobalt source, and the manganese source, the complexing agent, and the precipitating agent into a reaction vessel. More preferably, the mixed salt aqueous solution has a concentration of 2-3 mol / L. The mixed salt aqueous solution may be commercially available or may be prepared according to a conventional method in the art, but is not particularly limited thereto. 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 any precipitant known in the art for use in preparing nickel-cobalt-manganese ternary precursors, but is not limited thereto. The objectives of the present invention can be achieved to some extent. Preferably, the precipitant is selected from sodium hydroxide and / or potassium hydroxide. More preferably, the precipitant is provided in the form of an aqueous precipitant solution, and the concentration of the aqueous precipitant solution is 5-10 mol / L.

[0045] According to some embodiments of the present invention, in step (1), the complexing agent may be any complexing agent known in the art for use in preparing a nickel-cobalt-manganese ternary precursor, but is not limited thereto. The objectives of the present invention can be achieved to some extent. Preferably, the complexing agent is 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 complexing agent solution, and the mass fraction of the aqueous complexing agent solution is 20-30%.

[0046] According to some embodiments of the present invention, in step (1), the amounts of the precipitating agent and the complexing agent used are not particularly limited, as long as the amounts of the precipitating agent and the complexing agent used are such that the co-precipitation reaction meets the growth requirements of the precursor.

[0047] According to some embodiments of the present invention, in step (1), the aging, compression filtration, washing, and drying can be carried out by conventional 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 range of values ​​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 When the temperature of the first high-temperature sintering is low, D L / D S becomes larger.

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

[0051] According to some embodiments of the present invention, preferably, in step (2), D of the processed product of the agglomerated positive electrode material 50 is 5-15 μm, preferably 7-13 μm.

[0052] According to some embodiments of the present invention, the D of the nickel-cobalt-manganese ternary precursor 50 and D of the processed aggregate-like positive electrode material 50 is obtained by laser particle size distribution analyzer test.

[0053] According to some embodiments of the present invention, preferably, in step (2), the amount of the lithium source used is 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 any lithium source known in the art for preparing positive electrode materials, but is not limited thereto, and can achieve the objectives of the present invention to some extent. 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 crushing and sieving treatment can be performed by a conventional method well known to those skilled in the art, and is not particularly limited thereto. 50 However, it is sufficient to obtain a processed product of agglomerated positive electrode material that satisfies the above requirements.

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

[0057] According to some embodiments of the present invention, in step (3), the second cobalt source is preferably selected from at least one of cobalt oxide, cobalt(III) hydroxide, cobalt oxyhydroxide, cobalt fluoride, cobalt(II) hydroxide, tricobalt tetroxide, cobalt carbonate, and cobalt acetate, preferably at least one of cobalt oxide, cobalt(III) hydroxide, tricobalt tetroxide, cobalt oxyhydroxide, and cobalt(II) hydroxide. The adoption of the above preferred embodiments is advantageous for achieving uniform coating and controlling residual surface alkalinity.

[0058] According to some embodiments of the present invention, in step (3), the amount of the second cobalt source used is preferably 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.

[0059] According to some embodiments of the present invention, the amounts of the first cobalt source and the second cobalt source used are such that the total content of Co in the near-agglomerated multi-component positive electrode material satisfies n(Ni):n(Co):n(Mn)=x:y:z, where n(Co)=n(Co 1 )+n(Co 2 ) and the values ​​of x, y, and z can be defined and selected by referring to the above, and the explanation will be omitted here.

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

[0061] According to some embodiments of the present invention, in step (3), the crushing and sieving treatment can be performed by a conventional method well known to those skilled in the art, and is not particularly limited thereto. 50 However, it is only necessary to obtain a near-aggregated multi-component positive electrode material that satisfies the above requirements.

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

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

[0064] According to some embodiments of the present invention, preferably in step (3), the mixed raw materials further comprise 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 are each independently selected from M-containing compounds, preferably at least one of 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, the coating agent is preferably selected from at least one of V2O5, La2O3, SiO2, and B2O3.

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

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

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

[0071] According to some embodiments of the present invention, the total amount of the additive, the dopant, and the coating agent in the resulting multi-component positive electrode material satisfies n(Ni):n(Co):n(Mn):n(M)=x:y:z:b, where the values ​​of x, y, z, and b can be defined and selected with reference to the above, and further description thereof will be 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 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 agglomerated. 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.

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

[0074] 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.

[0075] 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.

[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 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 testing in the following manner. (1) Morphological test: Obtained by scanning electron microscope test using S-4800 model of Hitachi, Japan. (2) BET test: Obtained by Micromeritics Tristar 3020 type specific surface meter test, (3) XRD test: obtained by X-ray diffractometer test of Smart Lab 9KW model number of Nippon Rigakusha, (4)D 50 Particle size test: Obtained by Marvern Hydro 2000mu laser particle size distribution analyzer test, (5) Electrochemical performance test: In the following examples and comparative examples, the electrochemical performance of the multi-component cathode materials is tested using 2025 type button cells.

[0079] The manufacturing process of the 2025 button battery is as follows:

[0080] Electrode piece preparation: The multi-component positive electrode material, acetylene black, and polyvinylidene fluoride (PVDF) were thoroughly mixed with an appropriate amount of N-methylpyrrolidone (NMP) in a mass ratio of 95:3:2 to form a uniform slurry. The slurry was applied to an aluminum foil and dried at 120°C for 12 hours. The aluminum foil was then pressed under a pressure of 100 MPa to prepare a positive electrode piece with a diameter of 12 mm and a thickness of 120 μm. The loading of the multi-component positive electrode material was 15-16 mg / cm. 2 is.

[0081] Battery assembly: In a gas glove box filled with argon gas with a water and oxygen content of less than 5 ppm, the positive electrode pieces, separator, negative electrode pieces, and electrolyte were assembled into a 2025-type button cell battery and allowed to stand for 6 hours. The negative electrode pieces were made of lithium metal sheet with a diameter of 17 mm and a thickness of 1 mm, the separator was made of 25 μm thick polyethylene porous film (Celgard 2325), and the electrolyte was a mixture of equal parts of 1 mol / L LiPF6, ethylene carbonate (EC), and diethyl carbonate (DEC).

[0082] Electrochemical performance test: In the following examples and comparative examples, the electrochemical performance test was carried out on a 2025 button battery using a Shenzhen Newwell battery test system, and the 0.1C charge / discharge current density was 200mA / g.

[0083] The charge / discharge voltage range is controlled to 3-4.3V, and the button cell is charged / discharged at room temperature under 0.1C to evaluate the initial charge / discharge specific capacity and initial charge / discharge efficiency of the multi-component positive electrode material.

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

[0085] Rate performance test: The charge / discharge voltage range was controlled to 3.0-4.3V, and the button battery was charged / discharged at 0.1C for two cycles at room temperature, followed by one cycle at 0.2C, 0.33C, 0.5C, and 1C. The rate performance of the multi-component positive electrode 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 was the discharge specific capacity of the first cycle of the button battery, and the discharge specific capacity at 1C was the discharge specific capacity of the sixth cycle of the button battery.

[0086] Example 1 (1) mixing a nickel source, a first cobalt source, a manganese source, a complexing agent, and a precipitating agent to undergo a co-precipitation reaction to obtain a slurry, and then sequentially aging the slurry, compressing and filtering, washing, and drying to obtain a nickel-cobalt-manganese ternary precursor; the nickel source is nickel sulfate, the first cobalt source is cobalt sulfate, the manganese source is manganese sulfate, the complexing agent is provided in the form of an aqueous complexing agent solution and is ammonia water with a mass fraction of 25%, and the precipitating agent is provided in the form of an aqueous precipitating agent solution and is an 8 mol / L NaOH aqueous solution; Specifically, the mixing step is carried out by introducing the nickel source, the first cobalt source, the aqueous solution containing the manganese source, the aqueous complexing agent solution and the aqueous precipitating agent solution into a reactor in parallel flow under the protection of nitrogen gas, whereby Ni:Co 1 The molar ratio of Mn is shown in Table 1. The conditions of the co-precipitation reaction include a temperature of 60°C, a time of 20 hours, and a rotation speed of 800 rpm. The pH value of the co-precipitation reaction is shown in Table 1. The chemical formula, BET and D of the obtained nickel-cobalt-manganese ternary precursor 50 is shown in Table 2.

[0087] (2) Mixing a nickel-cobalt-manganese ternary precursor and a lithium source with a dopant, followed by a first high-temperature sintering process, followed by subsequent pulverization and sieving to obtain a quasi-agglomerated positive electrode material process product; The lithium source was lithium hydroxide. The types of dopants and the molar ratios of each raw material are shown in Table 1. The conditions of the first high-temperature sintering include: the time is 18 hours, the sintering atmosphere is oxygen, the temperature of the first high-temperature sintering is shown in Table 1, and the product of the first high-temperature sintering is naturally cooled to room temperature before being crushed and sieved; The chemical formula and D of the obtained agglomerated cathode material 50 is shown in Table 2.

[0088] (3) Mixing the processed product of the agglomerated positive electrode material with a second cobalt source, performing a second high-temperature sintering, and then performing crushing and sieving processes to obtain a agglomerated multi-component positive electrode material; The type of the second cobalt source and the molar ratio of each raw material used are shown in Table 1. The second high-temperature sintering conditions include a temperature of 720°C, a time of 10 hours, and an oxygen atmosphere. The second high-temperature sintering product is naturally cooled to room temperature before being crushed and sieved. The chemical structure and D of the obtained aggregated multi-component cathode material 50 is shown in Table 2.

[0089] Examples 2-5 The same processes as in Example 1 were used to prepare the agglomerated multi-component positive electrode materials, except for the raw materials and process parameters shown in Table 1. The chemical formulas 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 co-precipitation reaction was 11.2, and in step (2), the temperature of the first high-temperature sintering was 790°C, otherwise, the positive electrode materials were prepared in the same manner as in Example 1. The chemical formulas 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 co-precipitation reaction was 13.2, and in step (2), the temperature of the first high-temperature sintering was 970°C, otherwise, the positive electrode materials were prepared in the same manner as in Example 1. The chemical formulas and characteristic parameter test data of each product are shown in Table 2.

[0092] Comparative Example 3 The process of Example 1 was followed, but step (3) was omitted. The agglomerated cathode material was directly processed as the cathode material in the same manner as in Example 1. The chemical formulas and characteristic parameter test data of each product are shown in Table 2.

[0093] [Table 1] Note: The proportion of each element is calculated as a molar ratio.

[0094] Test Example (1) Morphological test The present invention shows scanning electron microscope (SEM) images of the positive electrode materials produced in the above examples and comparative examples. FIG. 1 is an SEM image of the quasi-agglomerated multi-component positive electrode material obtained in Example 1 of the present invention. FIG. 2 is an SEM image of the positive electrode material obtained in Comparative Example 1 of the present invention. FIG. 3 is an SEM image 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 agglomerated Comparative Example 1 and smaller than those in the single-crystal 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 rounded and spherical. (2) Physical property testing The present invention relates to the positive electrode material D produced in the above examples and comparative examples. 50 , BET, XRD (half width FWHM (104) ), the average particle size of the primary particles D S and the average particle size of the secondary particles D L The specific test results are shown in Table 2.

[0095] [Table 2-1] Note: Precursor* is a nickel-cobalt-manganese ternary precursor, processed product** is a processed product of a near-agglomerated positive electrode material, and positive electrode material*** is a near-agglomerated multi-component positive electrode material obtained in the examples or the positive electrode material obtained in the comparative examples.

[0096] [Table 2-2] Note: Precursor* is a nickel-cobalt-manganese ternary precursor, processed product** is a processed product of a near-agglomerated positive electrode material, and positive electrode material*** is a near-agglomerated multi-component positive electrode material obtained in the examples or the positive electrode material obtained in the comparative examples.

[0097] As can be seen from the results in Tables 1 and 2, in the manufacturing process of the agglomerated multi-component positive electrode material, increasing the temperature of the primary sintering (104) As the temperature increases and the size of the primary particles decreases, the average size of the primary particles increases, and 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 The FWHM of the aggregated material of Comparative Example 2 is large, and the FWHM of the aggregated multi-component positive electrode material of the present invention is large. (104) is between the single crystal type material and the agglomerated material, and is close to the single crystal type material. (3) Configuration test The present invention tested the Ni, Co, and Mn compositions at the center of the primary particles, the grain boundaries of the primary particles, and the surfaces of the secondary particles of the cathode materials prepared in the above examples and comparative examples to obtain the differences in Co content, and the specific test results are shown in Table 3. The Ni, Co, and Mn compositions are the average results of tests at multiple points.

[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 lot of Co enters the grain boundaries; when the primary particles are small, Co has difficulty entering the grain boundaries and is mostly coated on the surface of the secondary particles of the material.

[0101] (4) Electrochemical performance test The present invention tested the electrochemical performance of the positive electrode materials prepared in the above examples and comparative examples, including the initial 0.1C discharge specific capacity, 1C discharge specific capacity, rate performance, and cycle performance. The specific test results are shown in Table 4. The test temperature for the discharge specific capacity at 1C rate was 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 a poor material cycle. 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 capacity rate. Example 4 had less coated Co than Example 1, less grain boundary and surface Co, lower material speed, and worse cycles. Comparative Example 1 is an agglomerated material, with small primary particles and a tight structure. Co cannot enter the interior of secondary particles along the grain boundaries, and the grain boundary Co is very little, resulting in a low material capacity rate and poor cycle performance. Comparative Example 2 is a single crystal material, the primary particles are large, the primary particles are separated and independent from each other, Co is abundant on the surface of the material, and the material capacity rate is low. Comparative Example 3 has no Co coating, and the material speed is low and the cycle is poor.

[0104] Although the preferred embodiments of the present invention have been described in detail above, the present invention is not limited thereto. Within the technical concept of the present invention, the technical solutions of the present invention may be modified in a number of simple ways, including the combination of each technical feature in any other suitable manner, and these simple modifications and combinations are also considered to be the contents disclosed in the present invention, and all fall within 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, proposed on October 31, 2022, the contents of which are incorporated herein by reference.

Claims

1. 1. An aggregated multi-component positive electrode material, the multi-component positive electrode material having the structure shown in 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, and 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 positive electrode material is a secondary particle formed by aggregation of primary particles, the primary particles are spherical, and the average particle size of the primary particles is D 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 The range of values ​​that can be taken is 5-16, the grain boundaries of the primary particles and the surfaces of the secondary particles are rich in Co, the molar Co content of the centers of the primary particles is K1, the molar Co content of the grain boundaries of the primary particles is K2, and the molar Co content of the surfaces of the secondary particles is K3, wherein K2-K1≧0.5% and K3-K1≧1.5%.

2. 2. The aggregated multi-component positive electrode material of claim 1, wherein K2-K1≧1% and K3-K1≧3%.

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 average particle size D of the primary particles Ｓ is 1.2-1.8 μm, and / or the average particle size D of the secondary particles Ｌ is 7-13 μm, and / or D Ｌ / D Ｓ 3. The aggregated multi-component positive electrode material according to claim 1, wherein the range of values ​​of is 7 to 12.

4. The BET specific surface area of ​​the aggregated multi-component positive electrode material is 0.1-0.4 m ２ / g, And / or the full width at half maximum (FWHM) of the characteristic peak of the XRD test (104) of the aggregated multi-component positive electrode material （１０４） The range of values ​​taken by is 0.19-0.23, and / or D of the aggregated multi-component positive electrode material ５０ 3. The aggregated multi-component positive electrode material according to claim 1, wherein the particle size is 5-15 μm.

5. 10. The method of claim 1, wherein the method comprises: (1) mixing a nickel source, a first cobalt source, a manganese source, a complexing agent, and a precipitating agent to undergo a co-precipitation reaction to obtain a slurry, and then sequentially aging, compressing, filtering, washing, and drying the slurry to obtain a nickel-cobalt-manganese ternary precursor; (2) mixing the nickel-cobalt-manganese ternary precursor with a lithium source, performing a first high-temperature sintering process, and then performing a crushing and sieving process to obtain an aggregated cathode material; (3) mixing the processed agglomerated cathode material with a second cobalt source, subjecting the mixture to a second high-temperature sintering, followed by subsequent crushing and sieving to obtain an agglomerated multi-component cathode material.

6. In step (1), the pH value of the co-precipitation reaction is 10-13; and / or the temperature of the co-precipitation reaction is 40-80°C, the time is 5-40 hours, 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 / or D of the nickel-cobalt-manganese ternary precursor ５０ The method of claim 5, wherein the thickness is 5-15 μm.

7. In step (2), the temperature of the first high-temperature sintering is T, and the range of values ​​of T satisfies Formula II: [Equation 1] Here, C Ｎｉ is the mole percent of elemental nickel in the mixture of said nickel source, said first cobalt source, and said manganese source; and / or the first high-temperature sintering time is 10-30 h, and the sintering atmosphere is provided by an oxygen-containing gas; and / or D of the processed aggregate positive electrode material. ５０ is 5-15 μm, And / or, the amount of the lithium source used is 0.9≦[n(Li)] / [n(Ni)+n(Co) １ 6. The method according to claim 5, wherein n(Mn)+n(Mn)≦1.

1.

8. In step (3), the second high-temperature sintering conditions include a temperature of 200-1000°C, a time of 5-20 hours, and an oxygen-containing gas as the sintering atmosphere; and / or the second cobalt source is selected from at least one of cobalt oxide, cobalt(III) hydroxide, cobalt oxyhydroxide, cobalt fluoride, cobalt(II) hydroxide, tricobalt tetroxide, cobalt carbonate, and cobalt acetate; And / or, the amount of the second cobalt source used in the stoichiometric ratio is 0.005≦[n(Co ２ )] / [n(Ni)+n(Co １ 6. The method according to claim 5, wherein n(Mn)+n(Mn)≦0.

1.

9. In step (1), the mixed raw materials further comprise an additive, and / or in step (2), the mixed raw materials further comprise a dopant, and / or in step (3), the mixed raw materials further comprise a coating agent; The method of claim 5, wherein the additive, the dopant, and the coating agent may be the same or different and are each independently selected from M-containing compounds.

10. Use of the aggregated multi-component cathode material of claim 1 or the method of manufacture of claims 5-9 in a lithium ion battery.

11. A lithium ion battery comprising the aggregated multi-component positive electrode material of claim 1.

Images