A strontium-doped hydroxide precursor material, its preparation method and application

Abstract

The present invention relates to the technical field of new energy battery materials. Specifically, it relates to a strontium-doped hydroxide precursor material, a preparation method thereof, and an application thereof. The strontium-doped hydroxide precursor material includes strontium-doped hydroxide material layers and undoped hydroxide material layers that are periodically and alternately arranged from the inside to the outside; the chemical formula of the hydroxide material is Ni<subgt;a< / subgt;Co<subgt;b< / subgt;Mn<subgt>c< / subgt>Fe<subgt;d< / subgt>Cu<subgt>e< / subgt>M<subgt>f< / subgt;(OH)<subgt;2< / subgt>; M includes at least one of the elements Al, Ti, Ta, Mg, W, Ca, Nb, Cr, and Zr. By alternately growing the strontium-doped hydroxide material layer and the undoped hydroxide material layer, the present invention avoids the segregation growth of strontium sulfate and the formation of spiky protrusions on the surface of the precursor particles during current strontium ion doping, reduces the segregation degree of strontium ion doping, and improves the uniformity of the surface morphology of the strontium-doped hydroxide precursor material particles.

Description

Technical Field

[0001] The present invention relates to the technical field of new energy battery materials, and in particular, to a strontium-doped hydroxide precursor material, a preparation method thereof, and an application thereof. Background Art

[0002] Layered cathode materials are gradually widely used in lithium-ion batteries and sodium-ion batteries due to many advantages such as high energy density, long service life, and no memory effect. Currently, the industrial production of layered cathode materials often requires mixing a hydroxide precursor, a dopant, and a lithium salt / sodium salt, and then undergoing high-temperature calcination to obtain the corresponding cathode material. However, the doped elements cannot uniformly enter the bulk phase of the precursor. Especially when the particle size of the precursor is greater than 5 μm, it is even more difficult for the doped elements to move to the core part of the particle by high-temperature diffusion, and they often aggregate on the surface layer of the particle, resulting in the difficulty for such doped cathode materials to exhibit better battery performance. Therefore, in order to develop layered cathode materials with excellent battery performance and high crystal structure strength, more and more researchers have proposed to uniformly precipitate the ions required for doping in the cathode material inside the precursor particles by coprecipitation during the synthesis of the precursor, thereby effectively promoting the uniform distribution of the doped ions and the performance of the cathode material during the subsequent calcination process.

[0003] However, in the prior art during the process of preparing the precursor by coprecipitation reaction, due to the different precipitation rates of the doped elements, they often nucleate and grow independently and do not enter the precursor particles. Some precipitates formed by the doped elements segregate and grow on the surface of the precursor particles, seriously damaging the morphology of the precursor particles. Moreover, the hydroxide precipitates formed by many doped elements have a very high solubility, resulting in a serious shortage of the content of elements that can be doped into the particles. The above problems have hindered the industrial development of element doping in the precursor.

[0004] Therefore, the targeted development of a simple and feasible ion doping technology suitable for large-scale use for preparing high-performance cathode materials from the precursor has important promoting significance for the rapid development of lithium-ion batteries and sodium-ion batteries.

[0005] In view of this, the present invention is specifically proposed. Summary of the Invention

[0006] The first object of the present invention is to provide a strontium-doped hydroxide precursor material. By alternately growing a strontium-doped hydroxide material layer and an undoped hydroxide material layer, and using the undoped hydroxide material to coat the strontium-doped hydroxide material, the growth sites formed by the segregation of strontium sulfate on the surface of the precursor particles are effectively hidden, avoiding the segregation growth of strontium ions doped on the surface of the precursor particles and the formation of spiky protrusions in the prior art. Thus, a strontium-doped hydroxide precursor material with a low degree of strontium ion segregation and a uniform particle surface morphology is obtained, solving the problems of serious strontium ion segregation and damaged morphology in the production process of strontium-doped hydroxide precursors in the prior art.

[0007] The second object of the present invention is to provide a preparation method of a strontium-doped hydroxide precursor material. This preparation method has the advantages of being simple and easy to implement, capable of batch production, and maintaining the intact morphology of the particles of the strontium-doped hydroxide precursor material.

[0008] The third object of the present invention is to provide a cathode material.

[0009] The fourth object of the present invention is to provide a battery.

[0010] In order to achieve the above objects of the present invention, the following technical solutions are specifically adopted:

[0011] In the first aspect, the present invention provides a strontium-doped hydroxide precursor material, which includes a strontium-doped hydroxide material layer and an undoped hydroxide material layer that are periodically and alternately arranged (grown) from the inside to the outside. That is, the strontium-doped hydroxide precursor material sequentially includes a strontium-doped hydroxide material layer, an undoped hydroxide material layer, a strontium-doped hydroxide material layer, an undoped hydroxide material layer from the inside to the outside, and so on. Among them, the undoped hydroxide material layer and the strontium-doped hydroxide material layer are in a structure of layer-by-layer coating.

[0012] Among them, the innermost layer can be a strontium-doped hydroxide material layer or an undoped hydroxide material layer; the outermost layer can be a strontium-doped hydroxide material layer or an undoped hydroxide material layer.

[0013] In some specific embodiments of the present invention, the particle shape of the strontium-doped hydroxide precursor material is spherical. And, there are no spiky substances on the surface of the particles of the strontium-doped hydroxide precursor material.

[0014] Among them, the period of the alternating setting is at least 2 periods, including but not limited to the point value of any one of 3 periods, 4 periods, 5 periods, 6 periods, 7 periods, 8 periods, 9 periods, 10 periods, 11 periods, 12 periods, 13 periods, 15 periods, 18 periods, 20 periods, 22 periods, 24 periods, 25 periods, 26 periods, 28 periods, 30 periods or the range value between any two of them.

[0015] Among them, the chemical formula of the hydroxide material in the strontium-doped hydroxide material layer and the hydroxide material in the non-doped hydroxide material layer is Ni a Co b Mn c Fe d Cu e M f (OH)2;

[0016] That is, the main component of the non-doped hydroxide material layer is the hydroxide material (Ni a Co b Mn c Fe d Cu e M f (OH)2), in which strontium sulfate is not doped (not contained).

[0017] And the main component of the strontium-doped hydroxide material layer is the strontium-doped hydroxide material, that is, mainly composed of the hydroxide material (Ni a Co b Mn c Fe d Cu e M f (OH)2) and a small amount of strontium sulfate.

[0018] Among them, 0 ≤ a < 1, 0 ≤ b < 1, 0 ≤ c < 1, 0 ≤ d < 1, 0 ≤ e < 1, 0 ≤ f < 1, and a + b + c + d + e + f = 1; M includes at least one of Al element, Ti element, Ta element, Mg element, W element, Ca element, Nb element, Cr element and Zr element.

[0019] The present invention alternately grows and coats layer by layer the strontium-doped region and the non-doped region. By using the coating of the non-doped region on the strontium-doped region, the growth sites formed by the segregation of strontium sulfate on the surface of the precursor particles are effectively hidden, avoiding the segregation growth of strontium ions doped on the surface of the precursor particles and the formation of spiky protrusions, thereby obtaining a hydroxide precursor with a low degree of segregation of strontium ions doped and a uniform particle surface morphology.

[0020] The strontium-doped hydroxide precursor material provided by the present invention has a perfect particle morphology without spines, solving the problems of serious segregation of strontium ions and damaged morphology during the production of strontium-doped hydroxide precursors in the prior art.

[0021] Preferably, the thickness (single-layer thickness) of each layer of the strontium-doped hydroxide material layer is 0.1 - 5 μm, including but not limited to point values such as 0.2 μm, 0.5 μm, 1 μm, 1.5 μm, 2 μm, 2.5 μm, 3 μm, 3.5 μm, 4 μm, 4.5 μm or range values between any two of them. More preferably, it is 0.2 - 4.5 μm.

[0022] Preferably, the thickness (single-layer thickness) of each layer of the non-doped hydroxide material layer is 0.1 - 0.5 μm, including but not limited to point values such as 0.15 μm, 0.2 μm, 0.25 μm, 0.3 μm, 0.35 μm, 0.4 μm, 0.45 μm or range values between any two of them. More preferably, it is 0.1 - 0.3 μm.

[0023] Preferably, the D50 particle size of the strontium-doped hydroxide precursor material is 3 - 15 μm, including but not limited to point values such as 4 μm, 5 μm, 6 μm, 7 μm, 8 μm, 9 μm, 10 μm, 11 μm, 12 μm, 13 μm, 14 μm or range values between any two of them.

[0024] In a second aspect, the present invention provides a method for preparing the strontium-doped hydroxide precursor material as described above, comprising the following steps:

[0025] Mix a metal mixed salt solution, a precipitant solution and a complexing agent solution, and intermittently add a strontium source solution thereto to carry out a coprecipitation reaction to form periodically alternatingly growing strontium-doped hydroxide material layers and non-doped hydroxide material layers. After the coprecipitation reaction is completed, solid-liquid separation is carried out to obtain the strontium-doped hydroxide precursor material.

[0026] The present invention only needs to simply control the feeding timing of the strontium source solution, select to feed or stop feeding, and through the alternating growth coating technology of the strontium-doped region and the non-doped region, a hydroxide precursor with a uniform particle surface morphology and a low segregation degree of strontium ion doping can be obtained. This preparation method is simple, easy to implement, and easy to realize batch production.

[0027] The preparation method of the strontium-doped hydroxide precursor material provided by the present invention adopts an alternating growth and coating technology for doped regions and non-doped regions, avoiding the segregation of strontium sulfate during strontium doping precipitation, which causes long spicules to appear locally in the hydroxide precursor particles, resulting in serious deformation of the morphology. It maintains the perfect morphology of the precursor particles and provides an effective synthetic route for the preparation of strontium ion hydroxide precursors.

[0028] In some specific embodiments of the present invention, the preparation method of the strontium-doped hydroxide precursor material includes the following steps: mixing a metal mixed salt solution, a strontium source solution, a precipitant solution, and a complexing agent solution and carrying out a doped coprecipitation reaction to form a strontium-doped hydroxide material layer; stopping the introduction of the strontium source solution (the other raw material solutions except the strontium source solution continue to be introduced), and carrying out a non-doped coprecipitation reaction to form a non-doped hydroxide material layer, wherein the non-doped hydroxide material layer coats the surface of the strontium-doped hydroxide material layer. After a period of time, continue to introduce the strontium source solution and carry out a doped coprecipitation reaction to coat and form a strontium-doped hydroxide material layer on the surface of the non-doped hydroxide material layer, and then stop introducing the strontium source solution to coat and form a non-doped hydroxide material layer on the surface of the strontium-doped hydroxide material layer. Repeat this process to make the doped region (i.e., the strontium-doped hydroxide material layer) and the non-doped region (i.e., the non-doped hydroxide material layer) grow and coat alternately. After the reaction reaches the target particle size of the precursor, stop the reaction and stop introducing all reaction raw materials.

[0029] Preferably, the intermittent addition of the strontium source solution specifically includes: step (a), continuously adding the strontium source solution and reacting for 3 to 15 h (including but not limited to any point value or range value between any two of 4 h, 5 h, 6 h, 7 h, 8 h, 9 h, 10 h, 11 h, 12 h, 13 h, 14 h), and then stopping the addition of the strontium source solution and reacting for 1 to 5 h (including but not limited to any point value or range value between any two of 2 h, 3 h, 4 h).

[0030] Among them, step (a) is repeated at least 2 times, including but not limited to any point value or range value between any two of 3 times, 4 times, 5 times, 6 times, 7 times, 8 times, 9 times, 10 times, 11 times, 12 times, 13 times, 14 times, 15 times, 16 times, 17 times, 18 times, 19 times, 20 times, 22 times, 24 times, 25 times, 27 times, 28 times, 30 times. Preferably, it is repeated at least 5 times.

[0031] In some specific embodiments of the present invention, when the step (a) is repeated multiple times, if the particle size of the precursor has reached the target particle size, the reaction can be stopped (i.e., the addition of each raw material is stopped). That is, the last repetition of step (a) can end at any stage, without the need to continuously add the strontium source solution for reaction for 3 to 15 hours and then stop adding the strontium source solution and react for 1 to 5 hours.

[0032] In some specific embodiments of the present invention, the method for determining the feeding timing (selecting to feed or stop feeding) includes: judging whether to feed or stop feeding according to the reaction time of strontium doping and the reaction time of non-doping, or judging whether to feed or stop feeding according to the growth size of the particle size of the precursor during the strontium doping reaction and the growth size of the particle size of the precursor during the non-doping reaction.

[0033] For example, first feed for 3 to 15 hours for strontium doping reaction, then stop feeding for 1 to 5 hours for non-doping reaction, then feed for 3 to 15 hours for strontium doping reaction, and then stop feeding for 1 to 5 hours for non-doping reaction, and so on.

[0034] Or, first feed for strontium doping reaction, when the particle size reaches 0.1 to 5 μm, stop feeding for non-doping reaction, when the particle size of the precursor grows by 0.1 to 0.5 μm, feed again, when the particle size reaches 0.1 to 5 μm, stop again, and then when the particle size of the precursor grows by 0.1 to 0.5 μm, feed again, and so on.

[0035] Preferably, in step (a), continuously add the strontium source solution and react for 3 to 10 hours, and then stop adding the strontium source solution and react for 1 to 3 hours.

[0036] Preferably, the coprecipitation reaction needs to react until the D50 particle size of the precursor is 3 to 15 μm, including but not limited to any one of the point values of 4 μm, 5 μm, 6 μm, 7 μm, 8 μm, 9 μm, 10 μm, 11 μm, 12 μm, 13 μm, 14 μm or the range values between any two of them. That is, the target D50 particle size is 3 to 15 μm.

[0037] Preferably, the metal elements in the metal mixed salt solution include at least two of Ni, Co, Mn, Fe, Cu, Al, Ti, Ta, Mg, W, Ca, Nb, Cr, and Zr elements.

[0038] In some specific embodiments of the present invention, the metal elements in the metal mixed salt solution include at least two of Ni, Co, Mn, Fe, and Cu elements; optionally (it can be selected or not), it further includes at least one of Al, Ti, Ta, Mg, W, Ca, Nb, Cr, and Zr elements.

[0039] Preferably, the total mass concentration of metal elements (referring to all metal elements) in the metal mixed salt solution is 50-200 g / L, including but not limited to any point value among 60 g / L, 70 g / L, 80 g / L, 90 g / L, 100 g / L, 120 g / L, 150 g / L, 180 g / L or the range value between any two of them. More preferably, it is 100-200 g / L.

[0040] In some specific embodiments of the present invention, the anions in the metal mixed salt solution include sulfate ions, wherein the sulfate ions react with strontium ions to form strontium sulfate precipitate, thereby achieving doping. Optionally (optional), the anions in the metal mixed salt solution further include at least one of nitrate ions and chloride ions. That is, the metal mixed salt solution must contain sulfate ions, and may or may not contain nitrate ions and chloride ions.

[0041] That is, the salts used to prepare the metal mixed salt solution include sulfates, and at least one of nitrates or chlorides can also be selected and mixed with sulfates for use.

[0042] Preferably, the precipitating agent solution includes sodium hydroxide solution and / or potassium hydroxide solution.

[0043] Preferably, the mass fraction of the precipitating agent solution is 5%-28%, including but not limited to any point value among 6%, 7%, 8%, 9%, 10%, 12%, 15%, 18%, 20%, 22%, 25%, 27% or the range value between any two of them. More preferably, it is 6%-20%.

[0044] Preferably, the complexing agent solution includes at least one of ammonia water (aqueous ammonia solution), sodium citrate solution and ethylenediaminetetraacetic acid solution.

[0045] Preferably, the ammonia concentration of the ammonia water is 5-100 g / L, including but not limited to any point value among 7 g / L, 10 g / L, 15 g / L, 20 g / L, 25 g / L, 30 g / L, 35 g / L, 40 g / L, 50 g / L, 60 g / L, 70 g / L, 80 g / L, 90 g / L or the range value between any two of them. More preferably, it is 6-30 g / L. Wherein, the ammonia concentration refers to the mass concentration of ammonia monohydrate in the ammonia water.

[0046] Preferably, the strontium source solution includes at least one of strontium nitrate solution, strontium chloride solution, strontium acetate solution and strontium hydroxide solution.

[0047] Preferably, the mass concentration of the strontium source solution is 1 to 20 g / L, including but not limited to the point values of any one of 2 g / L, 3 g / L, 4 g / L, 5 g / L, 6 g / L, 7 g / L, 8 g / L, 9 g / L, 10 g / L, 12 g / L, 14 g / L, 15 g / L, 18 g / L or the range values between any two of them. More preferably, it is 2 to 15 g / L.

[0048] Preferably, during the coprecipitation reaction, the pH of the mixed material (reaction system) is 10 to 12, including but not limited to the point values of any one of 10.2, 10.5, 10.7, 11.0, 11.3, 11.5, 11.8 or the range values between any two of them. More preferably, it is 10 to 11.5.

[0049] Preferably, during the coprecipitation reaction, the temperature of the mixed material (reaction system) is 25 to 80 °C, including but not limited to the point values of any one of 30 °C, 35 °C, 40 °C, 45 °C, 50 °C, 55 °C, 60 °C, 65 °C, 70 °C, 75 °C or the range values between any two of them. More preferably, it is 30 to 70 °C.

[0050] In some specific embodiments of the present invention, the total time of the coprecipitation reaction is 30 to 150 h, including but not limited to the point values of any one of 35 h, 40 h, 50 h, 60 h, 70 h, 80 h, 90 h, 100 h, 110 h, 120 h, 130 h, 140 h or the range values between any two of them.

[0051] In some specific embodiments of the present invention, after the solid-liquid separation, it further includes the steps of washing, drying, sieving and demagnetizing the solid material obtained after the solid-liquid separation.

[0052] In some specific embodiments of the present invention, the feeding flow rate of the strontium source solution is 10 to 15 L / h, including but not limited to the point values of any one of 10.5 L / h, 11 L / h, 11.5 L / h, 12 L / h, 12.5 L / h, 13 L / h, 13.5 L / h, 14 L / h, 14.5 L / h or the range values between any two of them.

[0053] In some specific embodiments of the present invention, the feeding flow rate of the metal mixed salt solution is 60 to 90 L / h, including but not limited to the point values of any one of 62 L / h, 65 L / h, 67 L / h, 69 L / h, 70 L / h, 72 L / h, 75 L / h, 78 L / h, 80 L / h, 82 L / h, 85 L / h, 88 L / h or the range values between any two of them; preferably, it is 65 to 85 L / h.

[0054] In some specific embodiments of the present invention, the strontium doping amount in the strontium-doped hydroxide precursor material is 0.1% to 5%, including but not limited to the point values of any one of 0.2%, 0.5%, 0.8%, 1%, 1.3%, 1.5%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5% or the range values between any two of them.

[0055] In a third aspect, the present invention provides a cathode material, comprising the strontium-doped hydroxide precursor material as described above.

[0056] In a fourth aspect, the present invention provides a battery, comprising a positive electrode sheet mainly made of the cathode material as described above.

[0057] Among them, the battery includes a lithium-ion battery and a sodium-ion battery.

[0058] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0059] (1) For the strontium-doped hydroxide precursor material provided by the present invention, by alternately arranging the strontium-doped hydroxide material layer and the non-doped hydroxide material layer, and using the non-doped hydroxide material to coat the strontium-doped hydroxide material, the growth sites formed by the segregation of the precipitate formed by the strontium element on the surface of the precursor particles are effectively hidden, avoiding the segregation growth of strontium sulfate on the surface of the precursor particles and the formation of spiky protrusions during the current strontium ion doping, thereby reducing the segregation degree of strontium ion doping and improving the uniformity of the surface morphology of the strontium-doped hydroxide precursor material particles.

[0060] (2) The strontium-doped hydroxide precursor material provided by the present invention has a perfect particle morphology, no spiky objects on the particle surface, and a more uniform distribution of strontium elements inside.

[0061] (3) For the preparation method of the strontium-doped hydroxide precursor material provided by the present invention, only by simply controlling the feeding time of the strontium source solution, selecting to feed or not to feed, and through the alternating growth coating technology of the strontium-doped area and the non-doped area, a hydroxide precursor with a uniform surface morphology of particles and a low segregation degree of strontium ion doping can be obtained. This preparation method is simple, easy to implement, and easy to realize batch production. BRIEF DESCRIPTION OF THE DRAWINGS

[0062] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following will briefly introduce the drawings required for use in the description of the specific embodiments or the prior art. Obviously, the following drawings are some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0063] Figure 1FESEM image of the strontium-doped hydroxide precursor material prepared in Example 1 of the present invention;

[0064] Figure 2 FESEM image of the strontium-doped hydroxide precursor material prepared in Example 2 of the present invention;

[0065] Figure 3 FESEM image of the strontium-doped hydroxide precursor material prepared in Example 3 of the present invention;

[0066] Figure 4 FESEM image of the strontium-doped hydroxide precursor material prepared in Example 4 of the present invention;

[0067] Figure 5 FESEM image of the strontium-doped hydroxide precursor material prepared in Comparative Example 1 of the present invention;

[0068] Figure 6 FESEM image of the strontium-doped hydroxide precursor material prepared in Comparative Example 2 of the present invention. Detailed Description of the Invention

[0069] The technical solutions of the present invention will be clearly and completely described below in conjunction with the accompanying drawings and specific embodiments. However, those skilled in the art will understand that the following described embodiments are some embodiments of the present invention, rather than all embodiments, and are only used to illustrate the present invention and should not be construed as limiting the scope of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention. Those not specified in the embodiments are carried out under conventional conditions or conditions recommended by the manufacturer. The reagents or instruments not specified in the manufacturer are all conventional products that can be obtained through commercial purchase.

[0070] Example 1

[0071] The preparation method of the strontium-doped Ni 0.6 Co 0.2 Mn 0.2 (OH)2 hydroxide precursor material includes the following steps:

[0072] (1) Weigh nickel sulfate, cobalt nitrate, and manganese sulfate crystals according to the molar ratio of Ni:Co:Mn = 60:20:20, and dissolve them in a batching tank to prepare a mixed solution of multi-metal ions (i.e., a mixed metal salt solution). The total mass concentration of metal elements in this mixed solution is 180 g / L. Dissolve strontium nitrate crystals separately (in pure water) to prepare a strontium nitrate solution with a mass concentration of strontium element of 12 g / L. Prepare a precipitant solution with a mass fraction of sodium hydroxide of 19.7% using pure water and sodium hydroxide. Prepare ammonia water with an ammonia concentration (referring to the mass concentration of ammonia monohydrate in ammonia water, the same in the following examples) of 13.7 g / L for standby.

[0073] (2) Set the temperature of the reaction system to 55 °C, control the pH of the reaction system to 11.1, continuously introduce a protective gas into the reactor, feed the mixed solution of multi-metal ions at a flow rate of 69 L / h, feed the strontium nitrate solution at a flow rate of 10.3 L / h, the feed rate of the precipitant solution is specifically based on stabilizing the pH at 11.1, and feed ammonia water at a flow rate of 48 mL / min. Feed the above raw material liquids in parallel into a reactor containing a bottom liquid at 55 °C (pure water). The reactor needs to be continuously stirred to carry out the coprecipitation reaction.

[0074] During the coprecipitation reaction, the strontium nitrate solution is fed intermittently (that is, the strontium nitrate solution does not maintain a continuous feeding state, but chooses an intermittent feeding method, that is, it stops feeding after feeding for a period of time, then starts feeding and then stops again), to prevent the appearance of abnormal-shaped particles caused by the oriented growth of strontium sulfate on the particle surface. The feeding method of the strontium nitrate solution in this example is specifically as follows: First, feed for 5 h for strontium doping (forming a strontium-doped hydroxide material layer), then stop feeding for 2 h (forming an undoped hydroxide material layer), then feed for 5 h for strontium doping (forming a strontium-doped hydroxide material layer), and then immediately stop feeding for 2 h (forming an undoped hydroxide material layer), and so on (that is, forming a periodically alternating growth of strontium-doped hydroxide material layer and undoped hydroxide material layer); Finally, after a total reaction of 59 h (that is, the total coprecipitation reaction time is 59 h), at this time, the D50 particle size of the precursor is 8 μm, and solid-liquid separation is carried out to obtain a strontium-doped hydroxide precursor material with normal morphology, no strontium doping segregation, and a D50 particle size of 8 μm.

[0075] The strontium-doped hydroxide precursor material provided in this example includes a strontium-doped hydroxide material layer and an undoped hydroxide material layer that are periodically alternately arranged from the inside to the outside. Among them, the chemical formula of the hydroxide material in the strontium-doped hydroxide material layer and the hydroxide material in the undoped hydroxide material layer is Ni 0.6 Co 0.2 Mn 0.2 (OH)2.

[0076] As Figure 1 shown is the FESEM image of the strontium-doped hydroxide precursor material prepared in Example 1.

[0077] Example 2

[0078] The preparation method of the strontium-doped Ni 0.9 Co 0.1 (OH)2 hydroxide precursor material comprises the following steps:

[0079] (1) Weigh nickel acetate and cobalt sulfate crystals according to the molar ratio of Ni:Co = 90:10, and dissolve them in a batching tank to prepare a mixed solution of multi-metal ions (i.e., a mixed metal salt solution). The total mass concentration of metal elements in this mixed solution is 170 g / L. Prepare a strontium hydroxide solution with a mass concentration of strontium element of 11 g / L by dissolving strontium hydroxide alone (in pure water). Prepare a precipitant solution with a mass fraction of sodium hydroxide of 19.7% using pure water and sodium hydroxide. Prepare ammonia water with an ammonia concentration of 13.7 g / L for standby.

[0080] (2) Set the temperature of the reaction system to 68 °C, control the pH of the reaction system to 11.4, continuously introduce a protective gas into the reactor, feed the mixed solution of multi-metal ions at a flow rate of 67 L / h, feed the strontium hydroxide solution at a flow rate of 10.2 L / h, the feeding rate of the precipitant solution is specifically based on stabilizing the pH at 11.4, and feed ammonia water at a flow rate of 63 mL / min. Add the above raw material liquids in parallel into a reactor containing a bottom liquid at 68 °C (pure water). The reactor needs to be continuously stirred to carry out a co-precipitation reaction.

[0081] During the co-precipitation reaction, the strontium hydroxide solution is fed intermittently to prevent the appearance of abnormal-shaped particles caused by the directional growth of strontium sulfate on the particle surface. The feeding method of the strontium hydroxide solution in this example is specifically as follows: First, feed for 7 h for strontium doping (forming a strontium-doped hydroxide material layer), then stop feeding for 3 h (forming a non-doped hydroxide material layer), then feed for 7 h for strontium doping (forming a strontium-doped hydroxide material layer), and then immediately stop feeding for 3 h (forming a non-doped hydroxide material layer), and so on (i.e., forming a periodically alternating growth of strontium-doped hydroxide material layer and non-doped hydroxide material layer); Finally, after a total reaction of 81 h, at this time the D50 particle size of the precursor is 10 μm, and solid-liquid separation is carried out to obtain a strontium-doped hydroxide precursor material with normal morphology, no strontium doping segregation, and a D50 particle size of 10 μm.

[0082] The strontium-doped hydroxide precursor material provided in this embodiment includes strontium-doped hydroxide material layers and undoped hydroxide material layers that are periodically and alternately arranged from the inside to the outside. Among them, the chemical formula of the hydroxide material in the strontium-doped hydroxide material layer and the hydroxide material in the undoped hydroxide material layer is Ni 0.9 Co 0.1 (OH)2.

[0083] As Figure 2 shown is the FESEM image of the strontium-doped hydroxide precursor material prepared in Example 2.

[0084] Example 3

[0085] The preparation method of the strontium-doped Ni 0.33 Cu 0.33 Mn 0.34 (OH)2 hydroxide precursor material includes the following steps:

[0086] (1) Weigh nickel sulfate, copper acetate, and manganese nitrate crystals according to the molar ratio of Ni:Cu:Mn = 33:33:34, and dissolve them in a batching tank to prepare a mixed solution of multi-metal ions (i.e., a mixed metal salt solution). The total mass concentration of metal elements in this mixed solution is 140 g / L. Prepare a mixed strontium solution with a total mass concentration of strontium element of 2 g / L by dissolving strontium nitrate and strontium acetate crystals (in pure water). Prepare a precipitant solution with a mass fraction of sodium hydroxide of 12.7% using pure water and sodium hydroxide. Prepare ammonia water with an ammonia concentration of 10.3 g / L for standby.

[0087] (2) Set the temperature of the reaction system to 30 °C, control the pH of the reaction system to 11.0, continuously introduce a protective gas into the reactor, feed the mixed solution of multi-metal ions at a flow rate of 84 L / h, feed the mixed strontium solution at a flow rate of 10.6 L / h, the feed rate of the precipitant solution is specifically based on stabilizing the pH at 11.0, and feed ammonia water at a flow rate of 73 mL / min. Add the above raw material liquids in a co-current manner into a reactor containing a bottom liquid at 30 °C (pure water). The reactor needs to be continuously stirred to carry out a co-precipitation reaction.

[0088] During the coprecipitation reaction, the strontium mixed solution is intermittently fed to prevent the appearance of abnormal particles caused by the directional growth of strontium sulfate on the particle surface. In this example, the feeding method of the strontium mixed solution is specifically as follows: first, feed for strontium doping (forming a strontium-doped hydroxide material layer). When the D50 particle size of the particles reaches 2 μm, stop feeding (forming an undoped hydroxide material layer). When the D50 particle size of the precursor particles increases by 0.17 μm, feed again for strontium doping. When the D50 particle size of the particles increases by 2 μm, stop feeding again. When the D50 particle size of the precursor particles increases by 0.17 μm, feed again, and so on (that is, a strontium-doped hydroxide material layer and an undoped hydroxide material layer are formed to grow alternately in a cycle, where the thickness of each strontium-doped hydroxide material layer is 2 μm, and the thickness of each undoped hydroxide material layer is 0.17 μm); finally, after a total reaction of 52 h, at this time the D50 particle size of the precursor is 6.5 μm, and after solid-liquid separation, a strontium-doped hydroxide precursor material with normal morphology, no strontium doping segregation, and a D50 particle size of 6.5 μm is obtained.

[0089] The strontium-doped hydroxide precursor material provided in this example includes a strontium-doped hydroxide material layer and an undoped hydroxide material layer that are periodically alternately arranged from the inside to the outside. Among them, the chemical formula of the hydroxide material in the strontium-doped hydroxide material layer and the hydroxide material in the undoped hydroxide material layer is Ni 0.33 Cu 0.33 Mn 0.34 (OH)2.

[0090] As Figure 3 shown is the FESEM image of the strontium-doped hydroxide precursor material prepared in Example 3.

[0091] Example 4

[0092] The preparation method of the strontium-doped Ni 0.2 Cu 0.2 Fe 0.3 Mn 0.3 (OH)2 hydroxide precursor material includes the following steps:

[0093] (1) Weigh nickel sulfate, copper sulfate, ferrous sulfate, and manganese nitrate crystals according to the molar ratio of Ni:Cu:Fe:Mn = 20:20:30:30, and dissolve them in a batching tank to prepare a mixed solution of multi-metal ions (i.e., a metal mixed salt solution). The total mass concentration of the metal elements in this mixed solution is 100 g / L. Prepare a mixed strontium solution with a total mass concentration of strontium element of 6 g / L by dissolving strontium acetate crystals and strontium hydroxide crystals. Prepare a precipitant solution with a mass fraction of sodium hydroxide of 9.7% by using pure water and sodium hydroxide. Prepare ammonia water with an ammonia concentration of 6.7 g / L for standby.

[0094] (2) Set the temperature of the reaction system to 63 °C, control the pH of the reaction system to 10.7, continuously introduce a protective gas into the reactor, feed the mixed solution of multi-metal ions at a flow rate of 75 L / h, feed the strontium solution at a flow rate of 11.1 L / h, the feeding rate of the precipitant solution is specifically based on stabilizing the pH at 10.7, feed ammonia water at a flow rate of 57 mL / min, and add the above raw material solutions in parallel into the reactor containing a bottom solution at 63 °C (pure water). The reactor needs to be continuously stirred to carry out the co-precipitation reaction.

[0095] During the co-precipitation reaction, the strontium solution is fed intermittently to prevent the appearance of abnormal particles caused by the directional growth of strontium sulfate on the particle surface. In this example, the feeding method of the strontium solution is specifically as follows: first feed for 10 h for strontium doping (forming a strontium-doped hydroxide material layer), then stop feeding for 2 h (forming an undoped hydroxide material layer), then feed for 10 h for strontium doping (forming a strontium-doped hydroxide material layer), and then immediately stop feeding for 2 h (forming an undoped hydroxide material layer), and so on (i.e., forming a periodically alternating strontium-doped hydroxide material layer and an undoped hydroxide material layer); finally, after a total reaction of 37 h, at this time the D50 particle size of the precursor is 4.5 μm, and solid-liquid separation is carried out to obtain a strontium-doped hydroxide precursor material with normal morphology, no strontium doping segregation, and a D50 particle size of 4.5 μm.

[0096] The strontium-doped hydroxide precursor material provided in this example includes a strontium-doped hydroxide material layer and an undoped hydroxide material layer that are periodically alternately arranged from the inside to the outside. Among them, the chemical formula of the hydroxide material in the strontium-doped hydroxide material layer and the hydroxide material in the undoped hydroxide material layer is Ni 0.2 Cu 0.2 Fe 0.3 Mn 0.3 (OH)2.

[0097] As Figure 4 shown is the FESEM image of the strontium-doped hydroxide precursor material prepared in Example 4.

[0098] Example 5

[0099] The preparation method of the strontium-doped Ni 0.79 Mn 0.2 W 0.01 (OH)2 hydroxide precursor material includes the following steps:

[0100] (1) Weigh nickel sulfate, manganese nitrate, and ammonium tungstate crystals according to the molar ratio of Ni:Mn:W = 79:20:1, and dissolve them in a batching tank to prepare a mixed solution of multi-metal ions (i.e., a mixed metal salt solution). The total mass concentration of metal elements in this mixed solution is 156 g / L. Prepare a strontium nitrate solution with a strontium element mass concentration of 11 g / L by dissolving strontium nitrate crystals separately (in pure water). Prepare a precipitant solution with a sodium hydroxide mass fraction of 19.7% using pure water and sodium hydroxide. Prepare ammonia water with an ammonia concentration of 13.7 g / L for standby.

[0101] (2) Set the temperature of the reaction system to 30 °C, control the pH of the reaction system to 10.2, continuously introduce a protective gas into the reactor, feed the mixed solution of multi-metal ions at a flow rate of 75 L / h, feed the strontium nitrate solution at a flow rate of 11.1 L / h, the feed rate of the precipitant solution is specifically based on stabilizing the pH at 10.2, and feed ammonia water at a flow rate of 39 mL / min. Feed the above raw material liquids into the reactor containing a 30 °C bottom liquid (pure water) in a co-current manner. The reactor needs to be continuously stirred to carry out the co-precipitation reaction.

[0102] During the co-precipitation reaction, the strontium nitrate solution is fed intermittently to prevent the appearance of abnormal-shaped particles caused by the directional growth of strontium sulfate on the particle surface. The specific feeding method of the strontium nitrate solution in this example is as follows: First, feed for 3 h for strontium doping (forming a strontium-doped hydroxide material layer), then stop feeding for 1 h (forming an undoped hydroxide material layer), then feed for 3 h for strontium doping (forming a strontium-doped hydroxide material layer), and then immediately stop feeding for 1 h (forming an undoped hydroxide material layer), and so on (i.e., forming a periodically alternating growth of strontium-doped hydroxide material layer and undoped hydroxide material layer); finally, after a total reaction of 88 h, at this time, the D50 particle size of the precursor is 10 μm, and solid-liquid separation is carried out to obtain a strontium-doped hydroxide precursor material with normal morphology, no strontium doping segregation, and a D50 particle size of 10 μm.

[0103] The strontium-doped hydroxide precursor material provided in this example includes a strontium-doped hydroxide material layer and an undoped hydroxide material layer that are periodically alternately arranged from the inside to the outside. Among them, the chemical formula of the hydroxide material in the strontium-doped hydroxide material layer and the hydroxide material in the undoped hydroxide material layer is Ni 0.79 Mn 0.2 W 0.01 (OH)2.

[0104] Example 6

[0105] The strontium-doped Ni provided in this example 0.2 Fe 0.3 Mn 0.5The preparation method of the (OH)2 hydroxide precursor material comprises the following steps:

[0106] (1) Weigh nickel sulfate, ferrous sulfate, and manganese nitrate crystals according to the molar ratio of Ni:Fe:Mn = 20:30:50, and dissolve them in a batching tank to prepare a mixed solution of multi-metal ions (i.e., a metal mixed salt solution). The total mass concentration of metal elements in this mixed solution is 190 g / L. Dissolve strontium acetate crystals separately (in pure water) to prepare a strontium acetate solution with a strontium element mass concentration of 8 g / L. Prepare a precipitant solution with a sodium hydroxide mass fraction of 19.7% using pure water and sodium hydroxide. Prepare ammonia water with an ammonia concentration of 13.7 g / L for standby.

[0107] (2) Set the temperature of the reaction system to 56 °C, control the pH of the reaction system to 11.3, continuously introduce a protective gas into the reactor, feed the mixed solution of multi-metal ions at a flow rate of 75 L / h, feed the strontium acetate solution at a flow rate of 11.1 L / h, the feeding rate of the precipitant solution is specifically based on stabilizing the pH at 11.3, and feed ammonia water at a flow rate of 71 mL / min. Feed the above raw material solutions in parallel into a reactor containing a 56 °C bottom liquid (pure water). The reactor needs to be continuously stirred to carry out a co-precipitation reaction.

[0108] During the co-precipitation reaction, the strontium acetate solution is fed intermittently to prevent the appearance of abnormal-shaped particles caused by the directional growth of strontium sulfate on the particle surface. The feeding method of the strontium acetate solution in this example is specifically as follows: First, feed for 9 h for strontium doping, then stop feeding for 2 h, then feed the strontium acetate solution for 9 h for strontium doping, and then stop feeding the strontium acetate solution for 2 h again, and so on (i.e., form a strontium-doped hydroxide material layer and an undoped hydroxide material layer that grow alternately in a cycle); Finally, after a total reaction of 79 h, at this time, the D50 particle size of the precursor is 9 μm, and solid-liquid separation is carried out to obtain a strontium-doped hydroxide precursor material with a normal morphology, no strontium doping segregation, and a D50 particle size of 9 μm.

[0109] The strontium-doped hydroxide precursor material provided in this example includes a strontium-doped hydroxide material layer and an undoped hydroxide material layer that are periodically alternately arranged from the inside to the outside. Among them, the chemical formula of the hydroxide material in the strontium-doped hydroxide material layer and the hydroxide material in the undoped hydroxide material layer is Ni 0.2 Fe 0.3 Mn 0.5 (OH)2.

[0110] Example 7

[0111] The strontium-doped Ni 0.1 Co 0.1 Cu0.2 Fe 0.2 Mn 0.4 The preparation method of (OH)2 hydroxide precursor material comprises the following steps:

[0112] (1) Nickel sulfate, cobalt sulfate, copper nitrate, ferrous sulfate, and manganese sulfate crystals are weighed in a molar ratio of Ni:Co:Cu:Fe:Mn=10:10:20:20:40 and dissolved in a batching tank to prepare a mixed solution of polymetallic ions (i.e., a metal mixed salt solution), wherein the total mass concentration of the metal elements in the mixed solution is 190 g / L. Strontium acetate crystals are dissolved separately (in pure water) to prepare a strontium acetate solution with a mass concentration of strontium element of 11 g / L. Pure water and sodium hydroxide are used to prepare a precipitant solution with a mass fraction of sodium hydroxide of 19.7%. Ammonia water with an ammonia concentration of 13.7 g / L is prepared for use.

[0113] (2) The temperature of the reaction system is set to 45°C, the pH of the reaction system is controlled to 10.0, and protective gas is continuously introduced into the reactor. The mixed solution of polymetallic ions is fed at a flow rate of 75 L / h, the strontium acetate solution is fed at a flow rate of 11.1 L / h, the precipitant solution is fed at a flow rate specific to a stable pH at 10.0, and ammonia water is fed at a flow rate of 68 mL / min. The above raw material liquids are added in parallel to a reactor containing a bottom liquid (pure water) at 45°C. The reactor needs to be stirred continuously to carry out the co-precipitation reaction.

[0114] During the coprecipitation reaction, strontium acetate solution is fed intermittently, to block the appearance of special-shaped particles caused by the directional growth of strontium sulfate on the particle surface. The feeding mode of strontium acetate solution in the present embodiment is specifically as follows: advanced material is used for strontium doping, and when particle D50 particle diameter reaches 4.5 μm, feeding 1h is stopped, and then feeding 6h is used for strontium doping, and then feeding 1h is stopped, and feeding 6h is used for strontium doping again, so according to feeding time (feeding 6h-stopping 1h) repeated operation (i.e. forming strontium-doped hydroxide material layer and non-doped hydroxide material layer that are periodically grown alternately);Finally, through co-reaction 95h, now the D50 particle diameter of precursor is 10.5 μm, solid-liquid separation, obtains morphology normal, does not produce strontium-doped segregation and D50 particle diameter is 10.5 μm strontium-doped hydroxide precursor material.

[0115] The strontium doped hydroxide precursor material provided in this embodiment includes a strontium doped hydroxide material layer and a non-doped hydroxide material layer periodically arranged alternately from the inside to the outside. The chemical formula of the hydroxide material in the strontium doped hydroxide material layer and the hydroxide material in the non-doped hydroxide material layer is Ni 0.1 Co 0.1 Cu 0.2 Fe 0.2 Mn0.4 (OH)₂

[0116] Example 8

[0117] The strontium-doped Ni 0.2 Mn 0.75 Al 0.05 (OH)₂ hydroxide precursor material preparation method includes the following steps:

[0118] (1) Weigh nickel sulfate, manganese nitrate, and aluminum sulfate crystals according to the molar ratio of Ni:Mn:Al = 20:75:5, and dissolve them in a batching tank to prepare a mixed solution of multi-metal ions (i.e., a mixed metal salt solution). The total mass concentration of metal elements in this mixed solution is 190 g / L. Prepare a mixed strontium solution with a total mass concentration of strontium element of 1 g / L by separately dissolving strontium acetate and strontium chloride crystals (in pure water). Prepare a precipitant solution with a mass fraction of sodium hydroxide of 19.7% using pure water and sodium hydroxide. Prepare ammonia water with an ammonia concentration of 13.7 g / L for standby.

[0119] (2) Set the temperature of the reaction system to 70 °C, control the pH of the reaction system to 10.2, continuously introduce a protective gas into the reactor, feed the mixed solution of multi-metal ions at a flow rate of 75 L / h, feed the mixed strontium solution at a flow rate of 11.1 L / h, the feed rate of the precipitant solution is specifically based on stabilizing the pH at 10.2, and feed ammonia water at a flow rate of 97 mL / min. Add the above raw material liquids in a co-current manner into a reactor containing a bottom liquid at 70 °C (pure water). The reactor needs to be continuously stirred to carry out a co-precipitation reaction.

[0120] During the co-precipitation reaction, the mixed strontium solution is fed intermittently to prevent the appearance of abnormal-shaped particles caused by the oriented growth of strontium sulfate on the particle surface. The specific feeding method of the mixed strontium solution in this example is as follows: First, feed for 10 h for strontium doping, then stop feeding for 3 h, then feed for 10 h for strontium doping, and then stop feeding for 3 h again, and so on (i.e., form a strontium-doped hydroxide material layer and a non-doped hydroxide material layer that grow alternately in a cycle); Finally, after a total reaction of 103 h, at this time, the D50 particle size of the precursor is 10.5 μm, and solid-liquid separation is carried out to obtain a strontium-doped hydroxide precursor material with a normal morphology, no strontium doping segregation, and a D50 particle size of 10.5 μm.

[0121] The strontium-doped hydroxide precursor material provided in this example includes a strontium-doped hydroxide material layer and a non-doped hydroxide material layer that are periodically and alternately arranged from the inside to the outside. Among them, the chemical formula of the hydroxide material in the strontium-doped hydroxide material layer and the hydroxide material in the non-doped hydroxide material layer is Ni 0.2 Mn 0.75 Al0.05 (OH)2。

[0122] Comparative Example 1

[0123] The strontium-doped Ni 0.6 Co 0.2 Mn 0.2 (OH)2 hydroxide precursor material was prepared in substantially the same manner as in Example 1, except that the strontium nitrate solution was kept feeding continuously.

[0124] In this comparative example, solid-liquid separation was carried out when the D50 particle size of the precursor was 8 μm, and finally a strontium-doped hydroxide precursor material with abnormal particle morphology, strontium-doped segregation, and a D50 particle size of 8 μm was obtained.

[0125] The strontium-doped hydroxide precursor material provided in this comparative example is a strontium-doped hydroxide material, wherein the chemical formula of the hydroxide material is Ni 0.6 Co 0.2 Mn 0.2 (OH)2.

[0126] As Figure 5 shown is the FESEM image of the strontium-doped hydroxide precursor material prepared in Comparative Example 1.

[0127] Comparative Example 2

[0128] The strontium-doped Ni 0.9 Co 0.1 (OH)2 hydroxide precursor material was prepared in substantially the same manner as in Example 2, except that the strontium hydroxide solution was kept feeding continuously.

[0129] In this comparative example, solid-liquid separation was carried out when the D50 particle size of the precursor was 10 μm, and finally a strontium-doped hydroxide precursor material with abnormal particle morphology, strontium-doped segregation, and a D50 particle size of 10 μm was obtained.

[0130] The strontium-doped hydroxide precursor material provided in this comparative example is a strontium-doped hydroxide material, wherein the chemical formula of the hydroxide material is Ni 0.9 Co 0.1 (OH)2.

[0131] As Figure 6 shown is the FESEM image of the strontium-doped hydroxide precursor material prepared in Comparative Example 2.

[0132] From Figure 5 and Figure 6 it can be seen that strontium sulfate precipitation segregation occurred on the surfaces of the hydroxide precursor particles prepared in Comparative Example 1 and Comparative Example 2, resulting in long spines appearing locally on the particles and serious deformation of the morphology.

[0133] In Example 1 and Example 2 of this application, an improved intermittent feeding method of strontium ion solution is adopted, and strontium-doped Ni 0.6 Co 0.2 Mn 0.2 (OH)2 hydroxide precursors and FESEM images of strontium-doped Ni 0.9 Co 0.1 (OH)2 hydroxide precursors are obtained, as shown in Figure 1 and Figure 2 shown. It can be seen from Figure 1 and Figure 2 that the surface morphology of the precursor particles is normal, and it is difficult to observe prominent spicules or obvious segregation of strontium sulfate precipitation.

[0134] Furthermore, the present invention continues to adopt the improved intermittent feeding method of strontium ion solution to prepare strontium-doped Ni 0.33 Cu 0.33 Mn 0.34 (OH)2 and strontium-doped Ni 0.2 Cu 0.2 Fe 0.3 Mn 0.3 (OH)2 hydroxides in Example 3 and Example 4 respectively. Their FESEM images are as shown in Figure 3 and Figure 4 shown. It can be seen that there are no prominent spicules or obvious segregation of strontium sulfate precipitation in the morphology of the precursor particles, and the growth of the hydroxide precursor is normal.

[0135] The above test results show that the surface of the hydroxide precursors prepared in each example of the present invention has no spicules, and no obvious segregation of strontium sulfate is observed.

[0136] It can be seen that by alternately growing the strontium-doped hydroxide material layer and the non-doped hydroxide material layer, and using the non-doped hydroxide material to coat the strontium-doped hydroxide material, the growth sites formed by the segregation of the precipitation formed by the strontium element on the surface of the precursor particles are effectively hidden, avoiding the segregation growth of strontium sulfate and the formation of spiky protrusions on the surface of the precursor particles during current strontium ion doping, thereby obtaining a strontium-doped hydroxide precursor material with a low degree of strontium ion doping segregation and a uniform surface morphology of the particles.

[0137] Although the present invention has been illustrated and described with reference to specific embodiments, it should be understood that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it; those of ordinary skill in the art should understand that without departing from the spirit and scope of the present invention, the technical solutions described in the foregoing embodiments may be modified, or some or all of the technical features may be equivalently replaced; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention; therefore, this means that all such replacements and modifications that fall within the scope of the present invention are included in the appended claims.

Claims

1. A strontium-doped hydroxide precursor material, characterized in that, It includes a strontium-doped hydroxide material layer and an undoped hydroxide material layer that are periodically and alternately arranged from the inside to the outside, and the undoped hydroxide material layer and the strontium-doped hydroxide material layer are in a structure of layer-by-layer coating; Among them, the chemical formulas of the hydroxide material in the strontium-doped hydroxide material layer and the hydroxide material in the non-doped hydroxide material layer are Ni a Co b Mn c Fe d Cu e M f (OH)2; where 0≤a<1, 0≤b<1, 0≤c<1, 0≤d<1, 0≤e<1, 0≤f<1, and a + b + c + d + e + f = 1; M includes at least one of the elements Al, Ti, Ta, Mg, W, Ca, Nb, Cr, and Zr; The thickness of each strontium-doped hydroxide material layer is 0.1 - 5 μm; The thickness of each undoped hydroxide material layer is 0.1 - 0.5 μm.

2. The strontium-doped hydroxide precursor material according to claim 1, wherein The thickness of each strontium-doped hydroxide material layer is 0.2 - 4.5 μm.

3. The strontium-doped hydroxide precursor material according to claim 1, wherein The thickness of each undoped hydroxide material layer is 0.1 - 0.3 μm.

4. The strontium-doped hydroxide precursor material according to claim 1, wherein The D50 particle size of the strontium-doped hydroxide precursor material is 3 - 15 μm.

5. The preparation method of the strontium-doped hydroxide precursor material according to any one of claims 1 to 4, characterized in that, It includes the following steps: Mix the metal mixed salt solution, the precipitant solution, and the complexing agent solution, and intermittently add the strontium source solution thereto to carry out a coprecipitation reaction to form a strontium-doped hydroxide material layer and an undoped hydroxide material layer that grow periodically and alternately. After the coprecipitation reaction is completed, solid-liquid separation is carried out to obtain the strontium-doped hydroxide precursor material.

6. The preparation method of the strontium-doped hydroxide precursor material according to claim 5, characterized in that, The intermittent addition of the strontium source solution thereto specifically includes: (a) continuously adding the strontium source solution and reacting for 3 - 15 h, then stopping adding the strontium source solution and reacting for 1 - 5 h; wherein step (a) is repeated at least 2 times.

7. The preparation method of the strontium-doped hydroxide precursor material according to claim 6, characterized in that, Step (a) is repeated at least 5 times.

8. The preparation method of the strontium-doped hydroxide precursor material according to claim 6, characterized in that, In step (a), continuously add the strontium source solution and react for 3 - 10 h, then stop adding the strontium source solution and react for 1 - 3 h.

9. The preparation method of the strontium-doped hydroxide precursor material according to claim 5, characterized in that, The coprecipitation reaction is carried out until the particle D50 particle size is 3 - 15 μm.

10. The preparation method of the strontium-doped hydroxide precursor material according to claim 5, characterized in that, The metal elements in the metal mixed salt solution include at least two of the elements Ni, Co, Mn, Fe, Cu, Al, Ti, Ta, Mg, W, Ca, Nb, Cr, and Zr.

11. The preparation method of the strontium-doped hydroxide precursor material according to claim 5, characterized in that, The total mass concentration of the metal elements in the metal mixed salt solution is 50 - 200 g / L.

12. The preparation method of the strontium-doped hydroxide precursor material according to claim 11, characterized in that, The total mass concentration of the metal elements in the metal mixed salt solution is 100 - 200 g / L.

13. The preparation method of the strontium-doped hydroxide precursor material according to claim 5, characterized in that, The precipitant solution includes sodium hydroxide solution and / or potassium hydroxide solution.

14. The preparation method of the strontium-doped hydroxide precursor material according to claim 5, characterized in that, The mass fraction of the precipitant solution is 5% - 28%.

15. The preparation method of the strontium-doped hydroxide precursor material according to claim 14, wherein, The mass fraction of the precipitant solution is 6% - 20%.

16. The preparation method of the strontium-doped hydroxide precursor material according to claim 5, characterized in that, The complexing agent solution includes at least one of ammonia water, sodium citrate solution, and ethylenediaminetetraacetic acid solution.

17. The preparation method of the strontium-doped hydroxide precursor material according to claim 16, wherein, The ammonia concentration of the ammonia water is 5 - 100 g / L.

18. The preparation method of the strontium-doped hydroxide precursor material according to claim 17, wherein, The ammonia concentration of the ammonia water is 6 - 30 g / L.

19. The preparation method of the strontium-doped hydroxide precursor material according to claim 5, characterized in that, The strontium source solution includes at least one of strontium nitrate solution, strontium chloride solution, strontium acetate solution, and strontium hydroxide solution.

20. The preparation method of the strontium-doped hydroxide precursor material according to claim 19, wherein, The mass concentration of the strontium source solution is 1 - 20 g / L.

21. The preparation method of the strontium-doped hydroxide precursor material according to claim 20, characterized in that, The mass concentration of the strontium source solution is 2 - 15 g / L.

22. The preparation method of the strontium-doped hydroxide precursor material according to claim 5, characterized in that, During the coprecipitation reaction, the pH of the mixed material is 10 - 12.

23. The preparation method of the strontium-doped hydroxide precursor material according to claim 22, characterized in that, During the coprecipitation reaction, the pH of the mixed material is 10 - 11.

5.

24. The preparation method of the strontium-doped hydroxide precursor material according to claim 5, characterized in that, During the coprecipitation reaction, the temperature of the mixed materials is 25~80 °C.

25. The preparation method of the strontium-doped hydroxide precursor material according to claim 24, wherein, During the coprecipitation reaction, the temperature of the mixed materials is 30~70 °C.

26. A cathode material, characterized in that, It includes the strontium-doped hydroxide precursor material according to any one of claims 1 to 4.

27. A battery, characterized in that, It includes a positive electrode plate mainly made of the positive electrode material according to claim 26; Among them, the battery includes a lithium-ion battery or a sodium-ion battery.

Images