A precursor with high sphericity and tap density, its preparation method and application

Abstract

This invention relates to a precursor with high sphericity and tap density, its preparation method, and its application. The preparation method involves adding carbonate to a precipitant solution. Carbonates precipitate metal ions more readily than alkalis such as sodium hydroxide and potassium hydroxide. Therefore, in hydroxide precipitation systems, introducing carbonate ions induces crystal defects, thereby promoting the formation of amorphous branches and improving sphericity. Simultaneously, the degree of reaction between carbonate and metal ions is easier to control. This invention obtains a precursor with high sphericity and tap density by controlling the amount of carbonate added at different stages of the co-precipitation reaction.

Description

Technical Field

[0001] This invention belongs to the field of battery technology, and relates to a precursor, particularly a precursor with high sphericity and tap density, its preparation method and application. Background Technology

[0002] To obtain precursors with high tap density, suitable specific surface area, and dense growth, the preparation process often favors spherulite precursors with good sphericity. Spherulites are a polycrystalline morphology formed by crystal growth and evolution far from equilibrium conditions. The main factors contributing to spherulite formation include the static heterogeneity, dynamic heterogeneity, and amorphous branching of the system. Among these, amorphous branching is the core of spherulite growth. It occurs when the crystal is affected by external forces, temperature fields, or impurities, causing internal stress and crystal defects. These crystal defects then further induce internal stress, creating a continuous cycle that forms clusters of amorphous branches.

[0003] In the initial precursor growth process, in order to obtain a material with uniform element distribution and good crystallinity, the growth environment is not conducive to the generation of amorphous branches. Therefore, the morphology of the prepared precursor is mostly a material with coarse primary grains and poor sphericity. At the same time, it is easy to agglomerate during the reaction process, and the final precursor has poor tap density and large specific surface area.

[0004] To obtain precursors with better sphericity, current research proposes adding oxidants during the reaction process, most commonly by blowing in air. This method improves sphericity by introducing oxidation, specifically by oxidizing easily oxidized divalent metal ions to higher valences. This ionic difference introduces lattice distortion, continuously generating internal stress in the material and forming amorphous branches, thereby improving the sphericity of the precursor. However, current techniques struggle to quantify the degree of oxidation. Excessive oxidation leads to a blurry precursor morphology, poor crystallinity, and particle agglomeration, further deteriorating sphericity. Furthermore, the use of oxygen is limited to systems containing easily oxidized elements; in systems where metal elements are difficult to oxidize, it is challenging to induce amorphous branches to improve sphericity.

[0005] In addition, during the element doping process, it can be observed that the sphericity of the precursor becomes better after doping with certain elements. This is because the introduction of heteroatoms induces amorphous branching. However, doping can only be used in specific systems, and in other systems, it will lead to changes in the precursor composition.

[0006] Therefore, in order to obtain a precursor with good sphericity and high tap density, it is necessary to provide a precursor with high sphericity and tap density, as well as its preparation method and application. Summary of the Invention

[0007] The purpose of this invention is to provide a precursor with high sphericity and tap density, its preparation method and application, wherein the preparation method can obtain a precursor with high sphericity and tap density.

[0008] To achieve this objective, the present invention employs the following technical solution:

[0009] In a first aspect, the present invention provides a method for preparing a precursor with high sphericity and tap density, the method comprising the following steps:

[0010] A mixed salt solution, a complexing agent solution, and a precipitant solution are added concurrently to the base liquid to carry out a co-precipitation reaction, thereby obtaining the precursor with high sphericity and tap density.

[0011] The coprecipitation reaction includes a first stage, a second stage, and a third stage performed sequentially.

[0012] The precipitant in the precipitant solution includes carbonates and alkalis; the molar ratio of carbonates to alkalis in the precipitant solution is different in the first stage, the second stage, and the third stage.

[0013] Carbonates precipitate metal ions more readily than alkalis such as sodium hydroxide and potassium hydroxide. Therefore, in hydroxide precipitation systems, the introduction of carbonate ions induces crystal defects, thereby promoting the formation of amorphous branches and improving sphericity. At the same time, the degree of reaction between carbonates and metal ions is also easier to control. This invention obtains a precursor with high sphericity and tap density by controlling the amount of carbonate added at different stages of the coprecipitation reaction.

[0014] For example, the base solution of the present invention is an alkaline solution containing a complexing agent, and the concentration of the complexing agent in the base solution is 0.07-1 mol / L, for example, it can be 0.07 mol / L, 0.1 mol / L, 0.3 mol / L, 0.5 mol / L, 0.6 mol / L, 0.8 mol / L or 1 mol / L, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0015] For example, the pH value of the base liquid described in this invention is 10-13, such as 10, 11, 12 or 13, but not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0016] For example, the alkaline substances in the base liquid of the present invention include sodium carbonate and sodium hydroxide, and the molar ratio of sodium carbonate to sodium hydroxide is (2-10):1, for example, it can be 2:1, 4:1, 5:1, 6:1, 8:1 or 10:1, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0017] Preferably, in the first stage, the molar ratio of carbonate to alkali in the precipitant solution is (2-10):1, for example, it can be 2:1, 5:1, 6:1, 8:1 or 10:1, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0018] Preferably, in the second stage, the molar ratio of carbonate to alkali in the precipitant solution is (0.25-2):1, for example, it can be 0.25:1, 0.5:1, 1:1, 1.5:1 or 2:1, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0019] Preferably, in the third stage, the molar ratio of carbonate to alkali in the precipitant solution is (0.1-1):1, for example, it can be 0.1:1, 0.15:1, 0.2:1, 0.25:1, 0.5:1, 0.75:1 or 1:1, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0020] Preferably, the carbonate includes sodium carbonate and / or potassium carbonate.

[0021] Preferably, the alkali comprises sodium hydroxide and / or potassium hydroxide.

[0022] Preferably, during the first stage, the pH value is 10-13, for example, it can be 10, 11, 12 or 13, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0023] Preferably, in the first stage, the concentration of the complexing agent is 0.07-1 mol / L, for example, it can be 0.07 mol / L, 0.1 mol / L, 0.3 mol / L, 0.5 mol / L, 0.6 mol / L, 0.8 mol / L or 1 mol / L, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0024] Preferably, the particle size D50 at the end of the first stage is 1-5.2 μm, for example, it can be 1 μm, 1.5 μm, 2 μm, 2.5 μm, 3 μm, 3.5 μm, 3.9 μm, 4 μm, 5 μm or 5.2 μm, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0025] Preferably, in the second stage, the pH value is 8-11, for example, it can be 8, 9, 10 or 11, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0026] Preferably, in the second stage, the concentration of the complexing agent is 0.07-1 mol / L, for example, it can be 0.07 mol / L, 0.1 mol / L, 0.3 mol / L, 0.5 mol / L, 0.6 mol / L, 0.8 mol / L or 1 mol / L, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0027] Preferably, the particle size D50 at the end of the second stage is 2.3-10.4 μm, for example, it can be 2.3 μm, 3 μm, 4 μm, 5 μm, 6 μm, 8 μm, 8.7 μm, 9 μm, 10 μm or 10.4 μm, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0028] Preferably, in the third stage, the pH value is 8-11, for example, it can be 8, 9, 10 or 11, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0029] Preferably, in the third stage, the concentration of the complexing agent is 0.07-1 mol / L, for example, it can be 0.07 mol / L, 0.1 mol / L, 0.3 mol / L, 0.5 mol / L, 0.6 mol / L, 0.8 mol / L or 1 mol / L, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0030] Preferably, the particle size D50 at the end of the third stage is 2.5-16 μm, for example, it can be 2.5 μm, 4 μm, 5 μm, 10 μm, 12 μm, 15 μm or 16 μm, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0031] Preferably, the coprecipitation reaction is carried out under a protective atmosphere, the gas used in the protective atmosphere including nitrogen and / or an inert gas.

[0032] Preferably, the temperature of the coprecipitation reaction is 20-90℃, for example, it can be 20℃, 30℃, 40℃, 50℃, 60℃, 80℃ or 90℃, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable, with 80℃ being the preferred temperature.

[0033] Preferably, the concentration of the complexing agent solution is 1-10 mol / L, for example, it can be 1 mol / L, 3 mol / L, 5 mol / L, 8 mol / L or 10 mol / L, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0034] For example, the complexing agent in the complexing agent solution is ammonia.

[0035] Preferably, the concentration of the precipitant solution is 1-10 mol / L, for example, it can be 1 mol / L, 3 mol / L, 5 mol / L, 8 mol / L or 10 mol / L, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0036] Preferably, the concentration of the metal salt in the mixed salt solution is 1-3 mol / L, for example, it can be 1 mol / L, 1.5 mol / L, 2 mol / L, 2.5 mol / L or 3 mol / L, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0037] Preferably, the metal salt in the mixed salt solution conforms to the precursor chemical formula Ni. a Co b Mn c Fe d The (OH)2 is prepared in the following proportions: a+b+c+d=1, and 0≤a<1, 0≤b<1, 0≤c<1, 0≤d<1.

[0038] When c < 0.5 and d = 0, the resulting precursor is a ternary precursor;

[0039] When c>0.5 and d=0, the resulting precursor is a lithium-rich manganese-based precursor;

[0040] When d≠0, the resulting precursor is a sodium-electric precursor.

[0041] For example, the nickel salt in the mixed salt solution includes any one or a combination of at least two of nickel sulfate, nickel chloride, or nickel nitrate. Typical but non-limiting combinations include combinations of nickel sulfate and nickel chloride, nickel chloride and nickel nitrate, nickel sulfate and nickel nitrate, or combinations of nickel sulfate, nickel chloride, and nickel nitrate.

[0042] For example, the cobalt salt in the mixed salt solution includes any one or a combination of at least two of cobalt sulfate, cobalt chloride, or cobalt nitrate. Typical but non-limiting combinations include a combination of cobalt sulfate and cobalt chloride, a combination of cobalt chloride and cobalt nitrate, a combination of cobalt sulfate and cobalt nitrate, or a combination of cobalt sulfate, cobalt chloride, and cobalt nitrate.

[0043] For example, the manganese salt in the mixed salt solution includes any one or a combination of at least two of manganese sulfate, manganese chloride, or manganese nitrate. Typical but non-limiting combinations include combinations of manganese sulfate and manganese chloride, manganese chloride and manganese nitrate, manganese sulfate and manganese nitrate, or manganese sulfate, manganese chloride, and manganese nitrate.

[0044] For example, the iron salt in the mixed salt solution includes any one or a combination of at least two of ferrous sulfate, ferrous chloride, or ferrous nitrate. Typical but non-limiting combinations include combinations of ferrous sulfate and ferrous chloride, ferrous chloride and ferrous nitrate, ferrous sulfate and ferrous nitrate, or combinations of ferrous sulfate, ferrous chloride, and ferrous nitrate.

[0045] As a preferred embodiment of the preparation method described in the first aspect of the present invention, the preparation method includes the following steps:

[0046] (1) A mixed salt solution, complexing agent solution and precipitant solution are added to the bottom liquid in parallel to carry out the first stage of co-precipitation reaction;

[0047] In the first stage, the molar ratio of carbonate to alkali in the precipitant solution is (2-10):1;

[0048] In the first stage, the pH value of the coprecipitation reaction is 10-13, and the concentration of the complexing agent is 0.07-1 mol / L; the particle size D50 at the end of the first stage is 1-5.2 μm.

[0049] (2) The first stage of coprecipitation reaction is carried out when the particle size D50 is 1-5.2μm, and then the second stage of coprecipitation reaction is carried out.

[0050] In the second stage, the molar ratio of carbonate to alkali in the precipitant solution is (0.25-2):1;

[0051] In the second stage, the pH value of the coprecipitation reaction is 8-11, and the concentration of the complexing agent is 0.07-1 mol / L; the particle size D50 at the end of the second stage is 2.3-10.4 μm.

[0052] (3) The second stage of coprecipitation reaction, when the particle size D50 is 2.3-10.4μm, the third stage of coprecipitation reaction is carried out;

[0053] In the third stage, the molar ratio of carbonate to alkali in the precipitant solution is (0.1-1):1;

[0054] In the third stage, the pH value of the coprecipitation reaction is 8-11, and the concentration of the complexing agent is 0.07-1 mol / L; the particle size D50 at the end of the second stage is 2.5-16 μm.

[0055] In a second aspect, the present invention provides a precursor with high sphericity and tap density, wherein the precursor with high sphericity and tap density is prepared by the preparation method described in the first aspect.

[0056] Thirdly, the present invention provides an application of a precursor with high sphericity and tap density as described in the second aspect, wherein the precursor with high sphericity and tap density is used to prepare a cathode material.

[0057] The numerical range described in this invention includes not only the point values ​​listed above, but also any point values ​​within the numerical ranges not listed above. Due to space limitations and for the sake of brevity, this invention will not exhaustively list all the specific point values ​​included in the range.

[0058] Compared with the prior art, the present invention has the following beneficial effects:

[0059] Carbonates precipitate metal ions more readily than alkalis such as sodium hydroxide and potassium hydroxide. Therefore, in hydroxide precipitation systems, the introduction of carbonate ions induces crystal defects, thereby promoting the formation of amorphous branches and improving sphericity. At the same time, the degree of reaction between carbonates and metal ions is also easier to control. This invention obtains a precursor with high sphericity and tap density by controlling the amount of carbonate added at different stages of the coprecipitation reaction. Attached Figure Description

[0060] Figure 1 SEM images of the precursor with high sphericity and tap density obtained in Example 1-1;

[0061] Figure 2 SEM images of the precursors obtained in Comparative Examples 1-2;

[0062] Figure 3 SEM image of the precursor with high sphericity and tap density obtained in Example 2-1;

[0063] Figure 4 Here is a SEM image of the precursor obtained in Comparative Example 2-2;

[0064] Figure 5 SEM image of the precursor with high sphericity and tap density obtained in Example 3-1;

[0065] Figure 6 The image shows the SEM image of the precursor obtained in Example 3-2. Detailed Implementation

[0066] The technical solution of the present invention will be further illustrated below through specific embodiments. Those skilled in the art should understand that the embodiments described are merely illustrative of the present invention and should not be construed as limiting the invention in any way.

[0067] Example 1-1

[0068] This embodiment provides a method for preparing a precursor with high sphericity and tap density, the method comprising the following steps:

[0069] (1) In an argon atmosphere, a mixed salt solution, a complexing agent solution and a precipitant solution are added in parallel to the bottom liquid to carry out the first stage of co-precipitation reaction;

[0070] In the first stage, the molar ratio of sodium carbonate to sodium hydroxide in the precipitant solution is 3:1;

[0071] In the first stage, the pH value of the coprecipitation reaction was 10.6, and the concentration of the complexing agent was 0.5 mol / L; the particle size D50 at the end of the first stage was 2.6 μm.

[0072] The pH of the base solution was 10.6, the ammonia concentration was 0.5 mol / L, and the molar ratio of sodium carbonate to sodium hydroxide was 3:1.

[0073] (2) The first stage of coprecipitation reaction is carried out when the particle size D50 is 2.6 μm, and then the second stage of coprecipitation reaction is carried out.

[0074] In the second stage, the molar ratio of sodium carbonate to sodium hydroxide in the precipitant solution is 1:1;

[0075] In the second stage, the pH value of the coprecipitation reaction was 9.5, and the concentration of the complexing agent was 0.5 mol / L; the particle size D50 at the end of the second stage was 3.7 μm.

[0076] (3) The second stage of coprecipitation reaction, when the particle size D50 is 3.7μm, the third stage of coprecipitation reaction is carried out;

[0077] In the third stage, the molar ratio of sodium carbonate to sodium hydroxide in the precipitant solution is 0.15:1;

[0078] In the third stage, the pH value of the coprecipitation reaction was 9.5, and the concentration of the complexing agent was 0.5 mol / L; the particle size D50 at the end of the second stage was 5 μm.

[0079] In the first, second, and third stages, the temperature of the coprecipitation reaction is 80°C;

[0080] In this embodiment, the concentration of the mixed salt solution is 1 mol / L, and the flow rate is 8 L / min; the metal salt is prepared according to the precursor chemical formula Ni. 0.6 Co 0.2 Mn 0.2 The (OH)2 solution is prepared in the following proportions: nickel salt is nickel sulfate, cobalt salt is cobalt sulfate, and manganese salt is manganese sulfate; the complexing agent solution is ammonia water with a concentration of 5 mol / L, and the precipitant solution has a concentration of 6 mol / L.

[0081] The SEM image of the precursor obtained in this embodiment is as follows: Figure 1 As shown.

[0082] Examples 1-2

[0083] This embodiment provides a method for preparing a precursor with high sphericity and tap density, the method comprising the following steps:

[0084] (1) In an argon atmosphere, a mixed salt solution, a complexing agent solution and a precipitant solution are added in parallel to the bottom liquid to carry out the first stage of co-precipitation reaction;

[0085] In the first stage, the molar ratio of sodium carbonate to sodium hydroxide in the precipitant solution is 2:1;

[0086] In the first stage, the pH value of the coprecipitation reaction was 10, and the concentration of the complexing agent was 0.07 mol / L; the particle size D50 at the end of the first stage was 1 μm.

[0087] The pH of the base solution is 10, the ammonia concentration is 0.07 mol / L, and the molar ratio of sodium carbonate to sodium hydroxide is 2:1.

[0088] (2) The first stage of coprecipitation reaction is carried out when the particle size D50 is 1μm, and then the second stage of coprecipitation reaction is carried out.

[0089] In the second stage, the molar ratio of sodium carbonate to sodium hydroxide in the precipitant solution is 0.25:1;

[0090] In the second stage, the pH value of the coprecipitation reaction was 8, and the concentration of the complexing agent was 0.07 mol / L; the particle size D50 at the end of the second stage was 2.3 μm.

[0091] (3) The second stage of coprecipitation reaction, when the particle size D50 is 2.3 μm, the third stage of coprecipitation reaction is carried out;

[0092] In the third stage, the molar ratio of sodium carbonate to sodium hydroxide in the precipitant solution is 0.1:1;

[0093] In the third stage, the pH value of the coprecipitation reaction was 8, and the concentration of the complexing agent was 0.07 mol / L; the particle size D50 at the end of the second stage was 2.5 μm.

[0094] In the first, second, and third stages, the temperature of the coprecipitation reaction is 80°C;

[0095] In this embodiment, the concentration of the mixed salt solution is 1 mol / L, and the flow rate is 8 L / min; the metal salt is prepared according to the precursor chemical formula Ni. 0.6 Co 0.2 Mn 0.2 The (OH)2 solution is prepared in the following proportions: nickel salt is nickel sulfate, cobalt salt is cobalt sulfate, and manganese salt is manganese sulfate; the complexing agent solution is 1 mol / L ammonia water, and the precipitant solution is 1 mol / L.

[0096] Examples 1-3

[0097] This embodiment provides a method for preparing a precursor with high sphericity and tap density, the method comprising the following steps:

[0098] (1) In an argon atmosphere, a mixed salt solution, a complexing agent solution and a precipitant solution are added in parallel to the bottom liquid to carry out the first stage of co-precipitation reaction;

[0099] In the first stage, the molar ratio of sodium carbonate to sodium hydroxide in the precipitant solution is 10:1;

[0100] In the first stage, the pH value of the coprecipitation reaction was 13, and the concentration of the complexing agent was 1 mol / L; the particle size D50 at the end of the first stage was 3.9 μm.

[0101] The pH of the base solution is 13, the ammonia concentration is 1 mol / L, and the molar ratio of sodium carbonate to sodium hydroxide is 10:1.

[0102] (2) The first stage of coprecipitation reaction, when the particle size D50 is 3.9μm, the second stage of coprecipitation reaction is carried out;

[0103] In the second stage, the molar ratio of sodium carbonate to sodium hydroxide in the precipitant solution is 2:1;

[0104] In the second stage, the pH value of the coprecipitation reaction was 11, and the concentration of the complexing agent was 1 mol / L; the particle size D50 at the end of the second stage was 8.7 μm.

[0105] (3) The second stage of coprecipitation reaction, when the particle size D50 is 8.7μm, the third stage of coprecipitation reaction is carried out;

[0106] In the third stage, the molar ratio of sodium carbonate to sodium hydroxide in the precipitant solution is 0.25:1;

[0107] In the third stage, the pH value of the coprecipitation reaction was 11, and the concentration of the complexing agent was 1 mol / L; the particle size D50 at the end of the second stage was 16 μm.

[0108] In the first, second, and third stages, the temperature of the coprecipitation reaction is 80°C;

[0109] In this embodiment, the concentration of the mixed salt solution is 3 mol / L, and the flow rate is 8 L / min; the metal salt is prepared according to the precursor chemical formula Ni. 0.6 Co 0.2 Mn 0.2The (OH)2 solution is prepared in the following proportions: nickel salt is nickel sulfate, cobalt salt is cobalt sulfate, and manganese salt is manganese sulfate; the complexing agent solution is ammonia water with a concentration of 10 mol / L, and the precipitant solution has a concentration of 10 mol / L.

[0110] Examples 1-4

[0111] This embodiment provides a method for preparing a precursor with high sphericity and tap density, the method comprising the following steps:

[0112] (1) In an argon atmosphere, a mixed salt solution, a complexing agent solution and a precipitant solution are added in parallel to the bottom liquid to carry out the first stage of co-precipitation reaction;

[0113] In the first stage, the molar ratio of sodium carbonate to sodium hydroxide in the precipitant solution was 0.15:1;

[0114] In the first stage, the pH value of the coprecipitation reaction was 10.6, and the concentration of the complexing agent was 0.5 mol / L; the particle size D50 at the end of the first stage was 2.6 μm.

[0115] The pH of the base solution was 10.6, the ammonia concentration was 0.5 mol / L, and the molar ratio of sodium carbonate to sodium hydroxide was 0.15:1.

[0116] (2) The first stage of coprecipitation reaction is carried out when the particle size D50 is 2.6 μm, and then the second stage of coprecipitation reaction is carried out.

[0117] In the second stage, the molar ratio of sodium carbonate to sodium hydroxide in the precipitant solution is 1:1;

[0118] In the second stage, the pH value of the coprecipitation reaction was 9.5, and the concentration of the complexing agent was 0.5 mol / L; the particle size D50 at the end of the second stage was 3.7 μm.

[0119] (3) The second stage of coprecipitation reaction, when the particle size D50 is 3.7μm, the third stage of coprecipitation reaction is carried out;

[0120] In the third stage, the molar ratio of sodium carbonate to sodium hydroxide in the precipitant solution is 3:1;

[0121] In the third stage, the pH value of the coprecipitation reaction was 9.5, and the concentration of the complexing agent was 0.5 mol / L; the particle size D50 at the end of the second stage was 5 μm.

[0122] In the first, second, and third stages, the temperature of the coprecipitation reaction is 80°C;

[0123] In this embodiment, the concentration of the mixed salt solution is 1 mol / L, and the flow rate is 8 L / min; the metal salt is prepared according to the precursor chemical formula Ni.0.6 Co 0.2 Mn 0.2 The (OH)2 solution is prepared in the following proportions: nickel salt is nickel sulfate, cobalt salt is cobalt sulfate, and manganese salt is manganese sulfate; the complexing agent solution is ammonia water with a concentration of 5 mol / L, and the precipitant solution has a concentration of 6 mol / L.

[0124] Comparative Example 1-1

[0125] This comparative example provides a method for preparing a precursor, the method comprising the following steps:

[0126] (1) In an argon atmosphere, a mixed salt solution, a complexing agent solution and a precipitant solution are added in parallel to the bottom liquid to carry out the first stage of co-precipitation reaction;

[0127] In the first stage, the molar ratio of carbonate to alkali in the precipitant solution is 3:1;

[0128] In the first stage, the pH value of the coprecipitation reaction was 10.6, and the concentration of the complexing agent was 0.5 mol / L; the particle size D50 at the end of the first stage was 2.6 μm.

[0129] The pH of the base solution was 10.6, the ammonia concentration was 0.5 mol / L, and the molar ratio of sodium carbonate to sodium hydroxide was 3:1.

[0130] (2) The first stage of coprecipitation reaction is carried out when the particle size D50 is 2.6 μm, and then the second stage of coprecipitation reaction is carried out.

[0131] In the second stage, the molar ratio of sodium carbonate to sodium hydroxide in the precipitant solution is 3:1;

[0132] In the second stage, the pH value of the coprecipitation reaction was 9.5, and the concentration of the complexing agent was 0.5 mol / L; the particle size D50 at the end of the second stage was 3.7 μm.

[0133] (3) The second stage of coprecipitation reaction, when the particle size D50 is 3.7μm, the third stage of coprecipitation reaction is carried out;

[0134] In the third stage, the molar ratio of sodium carbonate to sodium hydroxide in the precipitant solution is 0.15:1;

[0135] In the third stage, the pH value of the coprecipitation reaction was 9.5, and the concentration of the complexing agent was 0.5 mol / L; the particle size D50 at the end of the second stage was 5 μm.

[0136] In the first, second, and third stages, the temperature of the coprecipitation reaction is 80°C;

[0137] In this comparative example, the concentration of the mixed salt solution was 1 mol / L, and the flow rate was 8 L / min; the metal salt was prepared according to the precursor chemical formula Ni. 0.6 Co 0.2 Mn 0.2 The (OH)2 solution is prepared in the following proportions: nickel salt is nickel sulfate, cobalt salt is cobalt sulfate, and manganese salt is manganese sulfate; the complexing agent solution is ammonia water with a concentration of 5 mol / L, and the precipitant solution has a concentration of 6 mol / L.

[0138] Comparative Examples 1-2

[0139] This comparative example provides a method for preparing a precursor, the method comprising the following steps:

[0140] (1) In an argon atmosphere, a mixed salt solution, a complexing agent solution and a precipitant solution are added in parallel to the bottom liquid to carry out the first stage of co-precipitation reaction;

[0141] In the first stage, the molar ratio of carbonate to alkali in the precipitant solution is 3:1;

[0142] In the first stage, the pH value of the coprecipitation reaction was 10.6, and the concentration of the complexing agent was 0.5 mol / L; the particle size D50 at the end of the first stage was 2.6 μm.

[0143] The pH of the base solution was 10.6, the ammonia concentration was 0.5 mol / L, and the molar ratio of sodium carbonate to sodium hydroxide was 3:1.

[0144] (2) The first stage of coprecipitation reaction is carried out when the particle size D50 is 2.6 μm, and then the second stage of coprecipitation reaction is carried out.

[0145] In the second stage, the molar ratio of sodium carbonate to sodium hydroxide in the precipitant solution is 3:1;

[0146] In the second stage, the pH value of the coprecipitation reaction was 9.5, and the concentration of the complexing agent was 0.5 mol / L; the particle size D50 at the end of the second stage was 3.7 μm.

[0147] (3) The second stage of coprecipitation reaction, when the particle size D50 is 3.7μm, the third stage of coprecipitation reaction is carried out;

[0148] In the third stage, the molar ratio of sodium carbonate to sodium hydroxide in the precipitant solution is 3:1;

[0149] In the third stage, the pH value of the coprecipitation reaction was 9.5, and the concentration of the complexing agent was 0.5 mol / L; the particle size D50 at the end of the second stage was 5 μm.

[0150] In the first, second, and third stages, the temperature of the coprecipitation reaction is 80°C;

[0151] In this comparative example, the concentration of the mixed salt solution was 1 mol / L, and the flow rate was 8 L / min; the metal salt was prepared according to the precursor chemical formula Ni. 0.6 Co 0.2 Mn 0.2 The (OH)2 solution is prepared in the following proportions: nickel salt is nickel sulfate, cobalt salt is cobalt sulfate, and manganese salt is manganese sulfate; the complexing agent solution is ammonia water with a concentration of 5 mol / L, and the precipitant solution has a concentration of 6 mol / L.

[0152] The SEM image of the precursor obtained in this comparative example is shown below. Figure 2 As shown.

[0153] Comparative Examples 1-3

[0154] This comparative example provides a method for preparing a precursor. Except for the first stage, where the precipitant in the precipitant solution is only sodium hydroxide, the rest is the same as in Example 1-1.

[0155] Comparative Examples 1-4

[0156] This comparative example provides a method for preparing a precursor. Except for the second stage, where the precipitant in the precipitant solution is only sodium hydroxide, the rest is the same as in Example 1-1.

[0157] Comparative Examples 1-5

[0158] This comparative example provides a method for preparing a precursor. Except for the third stage, where the precipitant in the precipitant solution is only sodium hydroxide, the rest is the same as in Example 1-1.

[0159] Example 2-1

[0160] This embodiment provides a method for preparing a precursor with high sphericity and tap density, the method comprising the following steps:

[0161] (1) In an argon atmosphere, a mixed salt solution, a complexing agent solution and a precipitant solution are added in parallel to the bottom liquid to carry out the first stage of co-precipitation reaction;

[0162] In the first stage, the molar ratio of sodium carbonate to sodium hydroxide in the precipitant solution is 7:1;

[0163] In the first stage, the pH value of the coprecipitation reaction was 12.8, and the concentration of the complexing agent was 0.1 mol / L; the particle size D50 at the end of the first stage was 3.6 μm.

[0164] The pH of the base solution was 13, the ammonia concentration was 0.1 mol / L, and the molar ratio of sodium carbonate to sodium hydroxide was 7:1.

[0165] (2) The first stage of coprecipitation reaction is carried out when the particle size D50 is 3.6 μm, and then the second stage of coprecipitation reaction is carried out.

[0166] In the second stage, the molar ratio of sodium carbonate to sodium hydroxide in the precipitant solution is 2:1;

[0167] In the second stage, the pH value of the coprecipitation reaction was 10.8, and the concentration of the complexing agent was 0.1 mol / L; the particle size D50 at the end of the second stage was 6.7 μm.

[0168] (3) The second stage of coprecipitation reaction, when the particle size D50 is 6.7μm, the third stage of coprecipitation reaction is carried out;

[0169] In the third stage, the molar ratio of sodium carbonate to sodium hydroxide in the precipitant solution is 1:1;

[0170] In the third stage, the pH value of the coprecipitation reaction was 10.8, and the concentration of the complexing agent was 0.1 mol / L; the particle size D50 at the end of the second stage was 8 μm.

[0171] In the first, second, and third stages, the temperature of the coprecipitation reaction is 80°C;

[0172] In this embodiment, the concentration of the mixed salt solution is 1.2 mol / L, and the flow rate is 12 L / min; the metal salt is prepared according to the precursor chemical formula Ni. 0.25 Mn 0.75 The solution is prepared by mixing (OH)2, with nickel salt being nickel sulfate and manganese salt being manganese sulfate; the complexing agent solution is ammonia water with a concentration of 2 mol / L and the precipitant solution has a concentration of 7 mol / L.

[0173] The SEM image of the precursor obtained in this embodiment is as follows: Figure 3 As shown.

[0174] Example 2-2

[0175] This embodiment provides a method for preparing a precursor with high sphericity and tap density, the method comprising the following steps:

[0176] (1) In an argon atmosphere, a mixed salt solution, a complexing agent solution and a precipitant solution are added in parallel to the bottom liquid to carry out the first stage of co-precipitation reaction;

[0177] In the first stage, the molar ratio of sodium carbonate to sodium hydroxide in the precipitant solution is 1:1;

[0178] In the first stage, the pH value of the coprecipitation reaction was 12.8, and the concentration of the complexing agent was 0.1 mol / L; the particle size D50 at the end of the first stage was 3.6 μm.

[0179] The pH of the base solution is 13, the ammonia concentration is 0.1 mol / L, and the molar ratio of sodium carbonate to sodium hydroxide is 1:1.

[0180] (2) The first stage of coprecipitation reaction is carried out when the particle size D50 is 3.6 μm, and then the second stage of coprecipitation reaction is carried out.

[0181] In the second stage, the molar ratio of sodium carbonate to sodium hydroxide in the precipitant solution is 2:1;

[0182] In the second stage, the pH value of the coprecipitation reaction was 10.8, and the concentration of the complexing agent was 0.1 mol / L; the particle size D50 at the end of the second stage was 6.7 μm.

[0183] (3) The second stage of coprecipitation reaction, when the particle size D50 is 6.7μm, the third stage of coprecipitation reaction is carried out;

[0184] In the third stage, the molar ratio of sodium carbonate to sodium hydroxide in the precipitant solution is 7:1;

[0185] In the third stage, the pH value of the coprecipitation reaction was 10.8, and the concentration of the complexing agent was 0.1 mol / L; the particle size D50 at the end of the second stage was 8 μm.

[0186] In the first, second, and third stages, the temperature of the coprecipitation reaction is 80°C;

[0187] In this embodiment, the concentration of the mixed salt solution is 1.2 mol / L, and the flow rate is 12 L / min; the metal salt is prepared according to the precursor chemical formula Ni. 0.25 Mn 0.75 The solution is prepared by mixing (OH)2, with nickel salt being nickel sulfate and manganese salt being manganese sulfate; the complexing agent solution is ammonia water with a concentration of 2 mol / L and the precipitant solution has a concentration of 7 mol / L.

[0188] Comparative Example 2-1

[0189] This comparative example provides a method for preparing a precursor with high sphericity and tap density, the method comprising the following steps:

[0190] (1) In an argon atmosphere, a mixed salt solution, a complexing agent solution and a precipitant solution are added in parallel to the bottom liquid to carry out the first stage of co-precipitation reaction;

[0191] In the first stage, the molar ratio of sodium carbonate to sodium hydroxide in the precipitant solution is 7:1;

[0192] In the first stage, the pH value of the coprecipitation reaction was 12.8, and the concentration of the complexing agent was 0.1 mol / L; the particle size D50 at the end of the first stage was 3.6 μm.

[0193] The pH of the base solution was 13, the ammonia concentration was 0.1 mol / L, and the molar ratio of sodium carbonate to sodium hydroxide was 7:1.

[0194] (2) The first stage of coprecipitation reaction is carried out when the particle size D50 is 3.6 μm, and then the second stage of coprecipitation reaction is carried out.

[0195] In the second stage, the molar ratio of sodium carbonate to sodium hydroxide in the precipitant solution is 7:1;

[0196] In the second stage, the pH value of the coprecipitation reaction was 10.8, and the concentration of the complexing agent was 0.1 mol / L; the particle size D50 at the end of the second stage was 6.7 μm.

[0197] (3) The second stage of coprecipitation reaction, when the particle size D50 is 6.7μm, the third stage of coprecipitation reaction is carried out;

[0198] In the third stage, the molar ratio of sodium carbonate to sodium hydroxide in the precipitant solution is 1:1;

[0199] In the third stage, the pH value of the coprecipitation reaction was 10.8, and the concentration of the complexing agent was 0.1 mol / L; the particle size D50 at the end of the second stage was 8 μm.

[0200] In the first, second, and third stages, the temperature of the coprecipitation reaction is 80°C;

[0201] In this comparative example, the concentration of the mixed salt solution was 1.2 mol / L, and the flow rate was 12 L / min; the metal salt was prepared according to the precursor chemical formula Ni. 0.25 Mn 0.75 The solution is prepared by mixing (OH)2, with nickel salt being nickel sulfate and manganese salt being manganese sulfate; the complexing agent solution is ammonia water with a concentration of 2 mol / L and the precipitant solution has a concentration of 7 mol / L.

[0202] Comparative Example 2-2

[0203] This comparative example provides a method for preparing a precursor with high sphericity and tap density, the method comprising the following steps:

[0204] (1) In an argon atmosphere, a mixed salt solution, a complexing agent solution and a precipitant solution are added in parallel to the bottom liquid to carry out the first stage of co-precipitation reaction;

[0205] In the first stage, the molar ratio of sodium carbonate to sodium hydroxide in the precipitant solution is 7:1;

[0206] In the first stage, the pH value of the coprecipitation reaction was 12.8, and the concentration of the complexing agent was 0.1 mol / L; the particle size D50 at the end of the first stage was 3.6 μm.

[0207] The pH of the base solution was 13, the ammonia concentration was 0.1 mol / L, and the molar ratio of sodium carbonate to sodium hydroxide was 7:1.

[0208] (2) The first stage of coprecipitation reaction is carried out when the particle size D50 is 3.6 μm, and then the second stage of coprecipitation reaction is carried out.

[0209] In the second stage, the molar ratio of sodium carbonate to sodium hydroxide in the precipitant solution is 7:1;

[0210] In the second stage, the pH value of the coprecipitation reaction was 10.8, and the concentration of the complexing agent was 0.1 mol / L; the particle size D50 at the end of the second stage was 6.7 μm.

[0211] (3) The second stage of coprecipitation reaction, when the particle size D50 is 6.7μm, the third stage of coprecipitation reaction is carried out;

[0212] In the third stage, the molar ratio of sodium carbonate to sodium hydroxide in the precipitant solution is 7:1;

[0213] In the third stage, the pH value of the coprecipitation reaction was 10.8, and the concentration of the complexing agent was 0.1 mol / L; the particle size D50 at the end of the second stage was 8 μm.

[0214] In the first, second, and third stages, the temperature of the coprecipitation reaction is 80°C;

[0215] In this comparative example, the concentration of the mixed salt solution was 1.2 mol / L, and the flow rate was 12 L / min; the metal salt was prepared according to the precursor chemical formula Ni. 0.25 Mn 0.75 The solution is prepared by mixing (OH)2, with nickel salt being nickel sulfate and manganese salt being manganese sulfate; the complexing agent solution is ammonia water with a concentration of 2 mol / L and the precipitant solution has a concentration of 7 mol / L.

[0216] The SEM image of the precursor obtained in this comparative example is shown below. Figure 4 As shown.

[0217] Comparative Examples 2-3

[0218] This comparative example provides a method for preparing a precursor with high sphericity and tap density. Except for the first stage, where the precipitant in the precipitant solution is only sodium hydroxide, the rest is the same as in Example 2-1.

[0219] Comparative Examples 2-4

[0220] This comparative example provides a method for preparing a precursor with high sphericity and tap density. Except for the second stage, where the precipitant in the precipitant solution is only sodium hydroxide, the rest is the same as in Example 2-1.

[0221] Comparative Examples 2-5

[0222] This comparative example provides a method for preparing a precursor with high sphericity and tap density. Except for the third stage, where the precipitant in the precipitant solution is only sodium hydroxide, the rest is the same as in Example 2-1.

[0223] Example 3-1

[0224] This embodiment provides a method for preparing a precursor with high sphericity and tap density, the method comprising the following steps:

[0225] (1) In an argon atmosphere, a mixed salt solution, a complexing agent solution and a precipitant solution are added in parallel to the bottom liquid to carry out the first stage of co-precipitation reaction;

[0226] In the first stage, the molar ratio of sodium carbonate to sodium hydroxide in the precipitant solution is 1:1;

[0227] In the first stage, the pH value of the coprecipitation reaction was 10.7, and the concentration of the complexing agent was 0.2 mol / L; the particle size D50 at the end of the first stage was 5.2 μm.

[0228] The pH of the base solution was 10.7, the ammonia concentration was 0.2 mol / L, and the molar ratio of sodium carbonate to sodium hydroxide was 1:1.

[0229] (2) The first stage of coprecipitation reaction is carried out when the particle size D50 is 5.2 μm; the second stage of coprecipitation reaction is carried out.

[0230] In the second stage, the molar ratio of sodium carbonate to sodium hydroxide in the precipitant solution is 1:2;

[0231] In the second stage, the pH value of the coprecipitation reaction was 8.8, and the concentration of the complexing agent was 0.2 mol / L; the particle size D50 at the end of the second stage was 10.4 μm.

[0232] (3) The second stage of coprecipitation reaction, when the particle size D50 is 10.4 μm, the third stage of coprecipitation reaction is carried out;

[0233] In the third stage, the molar ratio of sodium carbonate to sodium hydroxide in the precipitant solution is 1:8;

[0234] In the third stage, the pH value of the coprecipitation reaction was 8.8, and the concentration of the complexing agent was 0.2 mol / L; the particle size D50 at the end of the second stage was 12 μm.

[0235] In the first, second, and third stages, the temperature of the coprecipitation reaction is 80°C;

[0236] In this embodiment, the concentration of the mixed salt solution is 1.7 mol / L, and the flow rate is 2.7 L / min; the metal salt is prepared according to the precursor chemical formula Ni. 0.33 Fe 0.34 Mn 0.33 The (OH)2 solution is prepared in the following proportions: nickel salt is nickel sulfate, manganese salt is manganese sulfate; the complexing agent solution is ammonia water with a concentration of 7 mol / L, and the precipitant solution has a concentration of 3 mol / L.

[0237] The SEM image of the precursor obtained in this embodiment is as follows: Figure 5 As shown.

[0238] Example 3-2

[0239] This embodiment provides a method for preparing a precursor with high sphericity and tap density, the method comprising the following steps:

[0240] (1) In an argon atmosphere, a mixed salt solution, a complexing agent solution and a precipitant solution are added in parallel to the bottom liquid to carry out the first stage of co-precipitation reaction;

[0241] In the first stage, the molar ratio of sodium carbonate to sodium hydroxide in the precipitant solution is 1:8;

[0242] In the first stage, the pH value of the coprecipitation reaction was 10.7, and the concentration of the complexing agent was 0.2 mol / L; the particle size D50 at the end of the first stage was 5.2 μm.

[0243] The pH of the base solution is 10.7, the ammonia concentration is 0.2 mol / L, and the molar ratio of sodium carbonate to sodium hydroxide is 1:8.

[0244] (2) The first stage of coprecipitation reaction is carried out when the particle size D50 is 5.2 μm; the second stage of coprecipitation reaction is carried out.

[0245] In the second stage, the molar ratio of sodium carbonate to sodium hydroxide in the precipitant solution is 1:2;

[0246] In the second stage, the pH value of the coprecipitation reaction was 8.8, and the concentration of the complexing agent was 0.2 mol / L; the particle size D50 at the end of the second stage was 10.4 μm.

[0247] (3) The second stage of coprecipitation reaction, when the particle size D50 is 10.4 μm, the third stage of coprecipitation reaction is carried out;

[0248] In the third stage, the molar ratio of sodium carbonate to sodium hydroxide in the precipitant solution is 1:1;

[0249] In the third stage, the pH value of the coprecipitation reaction was 8.8, and the concentration of the complexing agent was 0.2 mol / L; the particle size D50 at the end of the second stage was 12 μm.

[0250] In the first, second, and third stages, the temperature of the coprecipitation reaction is 80°C;

[0251] In this embodiment, the concentration of the mixed salt solution is 1.7 mol / L, and the flow rate is 2.7 L / min; the metal salt is prepared according to the precursor chemical formula Ni. 0.33 Fe 0.34 Mn 0.33 The (OH)2 solution is prepared in the following proportions: nickel salt is nickel sulfate, manganese salt is manganese sulfate; the complexing agent solution is ammonia water with a concentration of 7 mol / L, and the precipitant solution has a concentration of 3 mol / L.

[0252] Comparative Example 3-1

[0253] This comparative example provides a method for preparing a precursor with high sphericity and tap density, the method comprising the following steps:

[0254] (1) In an argon atmosphere, a mixed salt solution, a complexing agent solution and a precipitant solution are added in parallel to the bottom liquid to carry out the first stage of co-precipitation reaction;

[0255] In the first stage, the molar ratio of sodium carbonate to sodium hydroxide in the precipitant solution is 1:1;

[0256] In the first stage, the pH value of the coprecipitation reaction was 10.7, and the concentration of the complexing agent was 0.2 mol / L; the particle size D50 at the end of the first stage was 5.2 μm.

[0257] The pH of the base solution was 10.7, the ammonia concentration was 0.2 mol / L, and the molar ratio of sodium carbonate to sodium hydroxide was 1:1.

[0258] (2) The first stage of coprecipitation reaction is carried out when the particle size D50 is 5.2 μm; the second stage of coprecipitation reaction is carried out.

[0259] In the second stage, the molar ratio of sodium carbonate to sodium hydroxide in the precipitant solution is 1:1;

[0260] In the second stage, the pH value of the coprecipitation reaction was 8.8, and the concentration of the complexing agent was 0.2 mol / L; the particle size D50 at the end of the second stage was 10.4 μm.

[0261] (3) The second stage of coprecipitation reaction, when the particle size D50 is 10.4 μm, the third stage of coprecipitation reaction is carried out;

[0262] In the third stage, the molar ratio of sodium carbonate to sodium hydroxide in the precipitant solution is 1:8;

[0263] In the third stage, the pH value of the coprecipitation reaction was 8.8, and the concentration of the complexing agent was 0.2 mol / L; the particle size D50 at the end of the second stage was 12 μm.

[0264] In the first, second, and third stages, the temperature of the coprecipitation reaction is 80°C;

[0265] The concentration of the mixed salt solution in this comparative example was 1.7 mol / L, and the flow rate was 2.7 L / min; the metal salt was prepared according to the precursor chemical formula Ni. 0.33 Fe 0.34 Mn 0.33 The (OH)2 solution is prepared in the following proportions: nickel salt is nickel sulfate, manganese salt is manganese sulfate; the complexing agent solution is ammonia water with a concentration of 7 mol / L, and the precipitant solution has a concentration of 3 mol / L.

[0266] Comparative Example 3-2

[0267] This comparative example provides a method for preparing a precursor with high sphericity and tap density, the method comprising the following steps:

[0268] (1) In an argon atmosphere, a mixed salt solution, a complexing agent solution and a precipitant solution are added in parallel to the bottom liquid to carry out the first stage of co-precipitation reaction;

[0269] In the first stage, the molar ratio of sodium carbonate to sodium hydroxide in the precipitant solution is 1:1;

[0270] In the first stage, the pH value of the coprecipitation reaction was 10.7, and the concentration of the complexing agent was 0.2 mol / L; the particle size D50 at the end of the first stage was 5.2 μm.

[0271] The pH of the base solution was 10.7, the ammonia concentration was 0.2 mol / L, and the molar ratio of sodium carbonate to sodium hydroxide was 1:1.

[0272] (2) The first stage of coprecipitation reaction is carried out when the particle size D50 is 5.2 μm; the second stage of coprecipitation reaction is carried out.

[0273] In the second stage, the molar ratio of sodium carbonate to sodium hydroxide in the precipitant solution is 1:1;

[0274] In the second stage, the pH value of the coprecipitation reaction was 8.8, and the concentration of the complexing agent was 0.2 mol / L; the particle size D50 at the end of the second stage was 10.4 μm.

[0275] (3) The second stage of coprecipitation reaction, when the particle size D50 is 10.4 μm, the third stage of coprecipitation reaction is carried out;

[0276] In the third stage, the molar ratio of sodium carbonate to sodium hydroxide in the precipitant solution is 1:1;

[0277] In the third stage, the pH value of the coprecipitation reaction was 8.8, and the concentration of the complexing agent was 0.2 mol / L; the particle size D50 at the end of the second stage was 12 μm.

[0278] In the first, second, and third stages, the temperature of the coprecipitation reaction is 80°C;

[0279] The concentration of the mixed salt solution in this comparative example was 1.7 mol / L, and the flow rate was 2.7 L / min; the metal salt was prepared according to the precursor chemical formula Ni. 0.33 Fe 0.34 Mn 0.33 The (OH)2 solution is prepared in the following proportions: nickel salt is nickel sulfate, manganese salt is manganese sulfate; the complexing agent solution is ammonia water with a concentration of 7 mol / L, and the precipitant solution has a concentration of 3 mol / L.

[0280] The SEM image of the precursor obtained in this comparative example is shown below. Figure 6 As shown.

[0281] Comparative Example 3-3

[0282] This comparative example provides a method for preparing a precursor with high sphericity and tap density. Except for the first stage, where the precipitant in the precipitant solution is only sodium hydroxide, the rest is the same as in Example 3-1.

[0283] Comparative Examples 3-4

[0284] This comparative example provides a method for preparing a precursor with high sphericity and tap density. Except for the second stage, where the precipitant in the precipitant solution is only sodium hydroxide, the rest is the same as in Example 3-1.

[0285] Comparative Examples 3-5

[0286] This comparative example provides a method for preparing a precursor with high sphericity and tap density. Except for the third stage, where the precipitant in the precipitant solution is only sodium hydroxide, the rest is the same as in Example 3-1.

[0287] Performance Characterization

[0288] (1) Dispersion test: The fineness index (SPAN) is obtained by laser particle size analyzer. The closer the SPAN is to 0, the better the dispersion. The closer the SPAN is to 1, the worse the dispersion.

[0289] (2) Tap density (TD) test: Performed in accordance with GB / T 6750-2008.

[0290] (3) Sphericity test: Performed in accordance with section 5.4 of GB / T 39251-2020. The sphericity value is obtained by dynamic particle image analysis. The closer the sphericity is to 1, the better the sphericity.

[0291] The results are shown in Table 1.

[0292] Table 1

[0293]

[0294]

[0295] In summary, carbonates precipitate metal ions more readily than alkalis such as sodium hydroxide and potassium hydroxide. Therefore, in hydroxide precipitation systems, the introduction of carbonate ions can induce crystal defects, thereby promoting the formation of amorphous branches and improving sphericity. At the same time, the degree of reaction between carbonates and metal ions is also easier to control. This invention obtains a precursor with high sphericity and tap density by controlling the amount of carbonate added at different stages of the co-precipitation reaction.

[0296] The applicant declares that the above description is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention fall within the protection and disclosure scope of the present invention.

Claims

1. A method for preparing a precursor with high sphericity and tap density, characterized in that, The preparation method includes the following steps: A mixed salt solution, a complexing agent solution, and a precipitant solution are added concurrently to the base liquid to carry out a co-precipitation reaction, thereby obtaining the precursor with high sphericity and tap density. The coprecipitation reaction includes a first stage, a second stage, and a third stage performed sequentially. The precipitant in the precipitant solution includes carbonates and alkalis; the molar ratio of carbonates to alkalis in the precipitant solution is different in the first stage, the second stage, and the third stage. In the first stage, the molar ratio of carbonate to alkali in the precipitant solution is (2-10):

1. In the second stage, the molar ratio of carbonate to alkali in the precipitant solution is (0.25-2):1; In the third stage, the molar ratio of carbonate to alkali in the precipitant solution is (0.1-1):

1.

2. The preparation method according to claim 1, characterized in that, The carbonates include sodium carbonate and / or potassium carbonate.

3. The preparation method according to claim 1, characterized in that, The alkali includes sodium hydroxide and / or potassium hydroxide.

4. The preparation method according to claim 1, characterized in that, In the first stage, the pH value is 10-13.

5. The preparation method according to claim 1, characterized in that, In the first stage, the concentration of the complexing agent is 0.07-1 mol / L.

6. The preparation method according to claim 1, characterized in that, The particle size D50 at the end of the first stage is 1-5.2 μm.

7. The preparation method according to claim 1, characterized in that, In the second stage, the pH value is 8-11.

8. The preparation method according to claim 1, characterized in that, In the second stage, the concentration of the complexing agent is 0.07-1 mol / L.

9. The preparation method according to claim 1, characterized in that, The particle size D50 at the end of the second stage is 2.3-10.4 μm.

10. The preparation method according to claim 1, characterized in that, During the third stage, the pH value is 8-11.

11. The preparation method according to claim 1, characterized in that, In the third stage, the concentration of the complexing agent is 0.07-1 mol / L.

12. The preparation method according to claim 1, characterized in that, The particle size D50 at the end of the third stage is 2.5-16 μm.

13. The preparation method according to claim 1, characterized in that, The concentration of the complexing agent solution is 1-10 mol / L.

14. The preparation method according to claim 1, characterized in that, The concentration of the precipitant solution is 1-10 mol / L.

15. The preparation method according to claim 1, characterized in that, The concentration of the metal salt in the mixed salt solution is 1-3 mol / L.

16. The preparation method according to claim 1, characterized in that, The metal salt in the mixed salt solution is formulated according to the precursor chemical formula Ni. a Co b Mn c Fe d The (OH)2 is prepared in the following proportions: a+b+c+d=1, and 0≤a<1, 0≤b<1, 0≤c<1, 0≤d<1.

17. The preparation method according to claim 1, characterized in that, The preparation method includes the following steps: (1) A mixed salt solution, complexing agent solution and precipitant solution are added to the bottom liquid in parallel to carry out the first stage of co-precipitation reaction; In the first stage, the molar ratio of carbonate to alkali in the precipitant solution is (2-10):1; In the first stage, the pH value of the coprecipitation reaction is 10-13, and the concentration of the complexing agent is 0.07-1 mol / L; The particle size D50 at the end of the first stage was 1-5.2 μm; (2) The first stage of coprecipitation reaction is carried out when the particle size D50 is 1-5.2μm, and then the second stage of coprecipitation reaction is carried out. In the second stage, the molar ratio of carbonate to alkali in the precipitant solution is (0.25-2):1; In the second stage, the pH value of the coprecipitation reaction is 8-11, and the concentration of the complexing agent is 0.07-1 mol / L; The particle size D50 at the end of the second stage was 2.3-10.4 μm; (3) The second stage of coprecipitation reaction, when the particle size D50 is 2.3-10.4μm, the third stage of coprecipitation reaction is carried out; In the third stage, the molar ratio of carbonate to alkali in the precipitant solution is (0.1-1):1; In the third stage, the pH value of the coprecipitation reaction is 8-11, and the concentration of the complexing agent is 0.07-1 mol / L; the particle size D50 at the end of the second stage is 2.5-16 μm.

Images