A ternary precursor preparation system and application thereof

Abstract

The application provides a ternary precursor preparation system and application thereof, and the system comprises a nickel salt solution feeding system, a cobalt salt solution feeding system, a manganese salt or aluminum salt solution feeding system, a complexing agent feeding system, a precipitant feeding system, a reaction kettle, an online monitoring unit and a DCS control system, wherein the nickel salt solution feeding system, the cobalt salt solution feeding system, the manganese salt or aluminum salt solution feeding system, the complexing agent feeding system and the precipitant feeding system are independently connected with the reaction kettle, the DCS control system is connected with the nickel salt solution feeding system, the cobalt salt solution feeding system, the manganese salt or aluminum salt solution feeding system, the complexing agent feeding system and the precipitant feeding system in parallel through signal interlocking, the online monitoring unit is arranged between the reaction kettle and the DCS control system, and the online monitoring unit is connected with the DCS control system through signal interlocking, and the system can control nucleation and growth of the ternary precursor.

Description

Technical Field

[0001] This invention belongs to the field of lithium-ion battery technology and relates to a ternary precursor preparation system and its application. Background Technology

[0002] Ternary materials with nickel, cobalt, and manganese (NCM) exhibit high specific capacity, long cycle life, low toxicity, and low cost. Furthermore, the three elements demonstrate excellent synergistic effects, leading to their widespread application. In NCM, nickel is the primary element involved in redox reactions; therefore, increasing the nickel content can effectively improve the specific capacity of ternary materials.

[0003] NCA materials combine the advantages of LiNiO2 and LiCoO2, not only having high reversible specific capacity and low material cost, but also enhancing structural stability and safety after aluminum (Al) doping, thereby improving the cycle stability of the material. NCM and NCA materials are currently two of the most researched commercial lower electrode materials.

[0004] CN111675247A discloses a method for preparing NCM high-nickel ternary cathode material precursors. The method uses soluble sulfates of nickel, manganese, and cobalt as raw materials and adopts a co-precipitation reaction process. During the reaction, green complexing agents potassium sodium tartrate and ammonia are used for staged complexation. After five processes of aging, washing, drying, sieving, and magnetic separation, NCM ternary precursors with high sphericity and coarse whiskers are obtained.

[0005] CN114890482A discloses a ternary cathode precursor, its preparation method, and its application. The preparation method includes: adding a mixed salt solution of nickel, cobalt, and manganese, a sulfate solution, a precipitant solution, and a complexing agent solution in parallel to a base solution to carry out a coprecipitation reaction; then, centrifuging and washing the product of the coprecipitation reaction to obtain the ternary cathode precursor.

[0006] The above methods all employ a mixed salt co-precipitation method to prepare ternary precursors. However, during the co-precipitation process, due to the different complexation constants of the complexing agents for nickel, cobalt, and manganese, and the different Ksp constants for manganese hydroxide and aluminum hydroxide compared to nickel hydroxide and cobalt hydroxide, manganese preferentially nucleates and precipitates. Furthermore, the loss of nickel, cobalt, and manganese / aluminum from the supernatant can cause deviations in the nickel, cobalt, and manganese / aluminum ratio in the product, affecting the proportion of metal elements and consequently the material's performance. Summary of the Invention

[0007] The purpose of this invention is to provide a ternary precursor preparation system and its application. The system described in this invention is used to prepare ternary precursors and can achieve precise control of element ratios and control of the nucleation and growth of nickel, cobalt, and manganese / aluminum precipitation.

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

[0009] In a first aspect, the present invention provides a ternary precursor preparation system, the system comprising a nickel salt solution feeding system, a cobalt salt solution feeding system, a manganese or aluminum salt solution feeding system, a complexing agent feeding system, a precipitant feeding system, a reactor, an online monitoring unit, and a DCS control system. The nickel salt solution feeding system, cobalt salt solution feeding system, manganese or aluminum salt solution feeding system, complexing agent feeding system, and precipitant feeding system are independently connected in parallel with the reactor. The DCS control system is independently connected in parallel with the nickel salt solution feeding system, cobalt salt solution feeding system, manganese or aluminum salt solution feeding system, complexing agent feeding system, and precipitant feeding system via signal interlocking. The online monitoring unit is located between the reactor and the DCS control system, and the online monitoring unit is connected to the DCS control system via signal interlocking.

[0010] In the ternary precursor preparation system of this invention, nickel, cobalt, and manganese / aluminum salt solutions are added separately, reducing the need for nickel-cobalt-manganese / aluminum mixing steps and simplifying the process. The online monitoring unit can monitor the concentration changes of various materials in real time during the reaction and adjust the feed rate of each material through a DCS control system. This reduces the deviation in the nickel-cobalt-manganese / aluminum ratio in the product caused by the loss of nickel-cobalt-manganese / aluminum from the supernatant, achieving precise control of the nickel-cobalt-manganese / aluminum ratio in the product. Furthermore, because the complexation constants and hydroxide Ksp constants of nickel, cobalt, and manganese / aluminum are different, the separate addition of nickel, cobalt, and manganese / aluminum salt solutions in this system allows adjustment of the relative positions of the nickel, cobalt, and manganese / aluminum salt solutions with the precipitant and complexing agent, thereby adjusting the precipitation sequence of nickel-cobalt-manganese / aluminum and the morphology of the primary and secondary crystal nuclei.

[0011] Preferably, each of the nickel salt solution feeding system, cobalt salt solution feeding system, manganese or aluminum salt solution feeding system, complexing agent feeding system, precipitant feeding system and reactor is equipped with an independent feed pump.

[0012] Preferably, a filter is installed between the online monitoring unit and the reactor.

[0013] Preferably, a discharge pump is provided between the filter and the reactor.

[0014] Preferably, the online monitoring unit includes a sampling unit, a transmission unit, a sample management unit, and an analysis unit connected in series.

[0015] Preferably, the analysis unit includes a data acquisition-processing-transmission module, a circulating cooling water module, a sample injection module, a reagent refrigeration module, and an online analyzer.

[0016] Preferably, the online analyzer includes an ICP-OES analyzer or an ICP-MS analyzer.

[0017] In a second aspect, the present invention provides a method for preparing a ternary precursor, the method using the ternary precursor preparation system as described in the first aspect, the method comprising the following steps:

[0018] Nickel salt solution, cobalt salt solution, manganese or aluminum salt solution, complexing agent and precipitant are injected into the reactor in parallel to carry out co-precipitation reaction;

[0019] The alkalinity, ammonia concentration, and concentration of various metal ions in the supernatant of the reactor are monitored in real time by the online monitoring unit to obtain online monitoring data. The online monitoring data is input into the DCS control system. The DCS control system controls the nickel salt solution feeding system, cobalt salt solution feeding system, manganese or aluminum salt solution feeding system, complexing agent feeding system, and precipitant feeding system to adjust the feed rate of each material, so as to achieve precise control of the nickel, cobalt, manganese / aluminum ratio in the product.

[0020] In the preparation method of the ternary precursor described in this invention, nickel, cobalt, and manganese / aluminum single salt solutions are added separately through a metering system. By adjusting the relative positions of the nickel salt solution, cobalt salt solution, and manganese / aluminum salt solution added into the reactor with the precipitant (sodium hydroxide) and complexing agent (ammonia), the nucleation and growth of nickel, cobalt, and manganese / aluminum precipitation can be controlled. By monitoring the concentration of each material in the supernatant of the reactor and adjusting the material feed rate, the element ratio in the product can be precisely controlled.

[0021] Preferably, the complexing agent comprises ammonia.

[0022] Preferably, the precipitant comprises a sodium hydroxide solution.

[0023] Preferably, the reaction vessel includes a bottom liquid.

[0024] Preferably, the base liquid includes ammonia and an alkaline solution.

[0025] Thirdly, the present invention provides a ternary precursor, which is prepared by the method described in the second aspect.

[0026] Preferably, the proportion of metal elements in the ternary precursor deviates by ±0.05 mol.

[0027] Fourthly, the present invention provides a cathode material, which is prepared by sintering a ternary precursor as described in the third aspect with a lithium source.

[0028] Fifthly, the present invention provides a lithium-ion battery comprising the positive electrode material as described in the fourth aspect.

[0029] Compared with the prior art, the present invention has the following beneficial effects:

[0030] (1) In the process of preparing ternary precursors, the system described in this invention can achieve precise control of the nickel-cobalt-manganese / aluminum ratio in the product through system control.

[0031] (2) The system of the present invention adds nickel, cobalt, manganese / aluminum salt solutions separately. By adjusting the relative positions of the nickel, cobalt, manganese / aluminum salt solutions with the precipitant and complexing agent, the precipitation order of nickel, cobalt, manganese / aluminum and the morphology of the primary and secondary crystal nuclei of nickel, cobalt, manganese / aluminum can be adjusted.

[0032] (3) The ternary precursor preparation system of the present invention can achieve precise control of the element ratio in the product, whether it is preparing NCM111, NCM622 or NCM811 precursors, and the deviation of metal elements in the precursor can be within ±0.05mol%. Attached Figure Description

[0033] Figure 1 This is a schematic diagram of a ternary precursor preparation system according to an embodiment of the present invention. 1-Nickel salt solution feeding system, 2-Cobalt salt solution feeding system, 3-Manganese salt solution feeding system, 4-Complexing agent feeding system, 5-Precipitant feeding system, 6-Reaction vessel, 7-Filter, 8-Online monitoring unit, 9-DCS control system.

[0034] Figure 2 This is a schematic diagram of the online monitoring unit in the ternary precursor preparation system of the present invention, 8.1-Sampling unit, 8.2-Transmission unit, 8.3-Sample management unit, 8.4-Analysis unit. Detailed Implementation

[0035] 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.

[0036] A schematic diagram of the ternary precursor preparation system used in this embodiment of the invention is shown below. Figure 1As shown, the nickel salt solution feeding system 1, cobalt salt solution feeding system 2, manganese salt solution feeding system 3, complexing agent feeding system 4, and precipitant feeding system 5 are independently connected in parallel with the reactor 6. Each of these systems has an independent feed pump. The DCS control system 9 is independently connected in parallel with each of the following systems via signal interlocking: nickel salt solution feeding system 1, cobalt salt solution feeding system 2, manganese salt solution feeding system 3, complexing agent feeding system 4, precipitant feeding system 5, and reactor 6. One side of the online monitoring unit 8 is connected to the reactor 6, and a filter 7 is installed between the online monitoring unit 8 and the reactor 6. A discharge pump is installed between the filter 7 and the reactor 6. The other side of the online monitoring unit 8 is connected to the DCS control system 9 via signal interlocking.

[0037] A schematic diagram of the online monitoring unit is shown below. Figure 2 As shown, 8.1 is the sampling unit, 8.2 is the transmission unit, 8.3 is the sample management unit, and 8.4 is the analysis unit;

[0038] The analysis unit is equipped with a data acquisition-processing-transmission module, a circulating cooling water module, a sample injection module, a reagent refrigeration module, and an online analyzer.

[0039] Example 1

[0040] This embodiment provides an NCM111 ternary precursor. The NCM111 ternary precursor is prepared using the aforementioned ternary precursor preparation system, and the preparation method of the ternary precursor is as follows:

[0041] Nickel salt solution, cobalt salt solution, aluminum salt solution, complexing agent, and precipitant were injected into the reactor in a co-flow manner according to the ratio of Ni:Co:Mn=1:1:1 for co-precipitation reaction. The complexing agent was 2 mol / L ammonia water, the precipitant was 3 mol / L sodium hydroxide solution, the ammonia concentration in the bottom liquid of the reactor was [value missing], and the pH was 11.5.

[0042] The alkalinity, ammonia concentration, and concentration of various metal ions in the supernatant of the reactor are monitored in real time by an online monitoring unit to obtain online monitoring data. The online monitoring data is input into the DCS control system. The DCS control system controls the nickel salt solution feeding system, cobalt salt solution feeding system, manganese or aluminum salt solution feeding system, complexing agent feeding system, and precipitant feeding system to adjust the relative positions of each system and the feed rate of each material (the DCS control system adjusts the position and flow rate of each feeding system) to obtain the NCM111 ternary precursor.

[0043] Example 2

[0044] This embodiment provides an NCM622 ternary precursor. The NCM622 ternary precursor is prepared using the aforementioned ternary precursor preparation system, and the preparation method of the ternary precursor is as follows:

[0045] Nickel salt solution, cobalt salt solution, aluminum salt solution, complexing agent, and precipitant were injected into the reactor in a co-flow manner according to the ratio of Ni:Co:Mn=6:2:2 for co-precipitation reaction. The complexing agent was 2 mol / L ammonia water, the precipitant was 3 mol / L sodium hydroxide solution, the ammonia concentration in the bottom liquid of the reactor was [value missing], and the pH was 11.5.

[0046] The alkalinity, ammonia concentration, and concentration of various metal ions in the supernatant of the reactor are monitored in real time by an online monitoring unit to obtain online monitoring data. The online monitoring data is input into the DCS control system. The DCS control system controls the nickel salt solution feeding system, cobalt salt solution feeding system, manganese or aluminum salt solution feeding system, complexing agent feeding system, and precipitant feeding system to adjust the relative positions of each system and the feed rate of each material (the DCS control system adjusts the position and flow rate of each feeding system) to obtain the NCM622 ternary precursor.

[0047] Example 3

[0048] This embodiment provides an NCM811 ternary precursor. The NCM811 ternary precursor is prepared using the aforementioned ternary precursor preparation system, and the preparation method of the ternary precursor is as follows:

[0049] Nickel salt solution, cobalt salt solution, aluminum salt solution, complexing agent, and precipitant were injected into the reactor in parallel streams according to the ratio of Ni:Co:Mn=8:1:1 for co-precipitation reaction. The complexing agent was 2 mol / L ammonia water, the precipitant was 3 mol / L sodium hydroxide solution, the ammonia concentration in the bottom liquid of the reactor was [value missing], and the pH was 11.5.

[0050] The alkalinity, ammonia concentration, and concentration of various metal ions in the supernatant of the reactor are monitored in real time by an online monitoring unit to obtain online monitoring data. The online monitoring data is input into the DCS control system. The DCS control system controls the nickel salt solution feeding system, cobalt salt solution feeding system, manganese or aluminum salt solution feeding system, complexing agent feeding system, and precipitant feeding system to adjust the relative positions of each system and the feed rate of each material (the DCS control system adjusts the position and flow rate of each feeding system) to obtain the NCM811 ternary precursor.

[0051] Comparative Example 1

[0052] In this comparative example, the NCM111 precursor was prepared using a conventional co-precipitation method.

[0053] Comparative Example 2

[0054] In this comparative example, the NCM622 precursor was prepared using a conventional co-precipitation method.

[0055] Comparative Example 3

[0056] In this comparative example, the NCM811 precursor was prepared using a conventional co-precipitation method.

[0057] Performance testing:

[0058] The molar percentages of elements in the precursors prepared in the test examples and comparative examples are shown in Table 1.

[0059] Table 1

[0060]

[0061] As shown in Table 1, a comparison of Examples 1-3 and Comparative Examples 1-3 reveals that the ternary precursor preparation system of this invention can precisely control the elemental ratio in the product, regardless of whether it is preparing NCM111, NCM622, or NCM811 precursors. The deviation of metal elements in the precursor can be within ±0.05 mol%. In contrast, the existing technology using co-precipitation methods achieves a metal ratio deviation control standard of ±0.3 mol%.

[0062] 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 ternary precursor preparation system, characterized in that, The system includes a nickel salt solution feeding system, a cobalt salt solution feeding system, a manganese or aluminum salt solution feeding system, a complexing agent feeding system, a precipitant feeding system, a reactor, an online monitoring unit, and a DCS control system. The nickel salt solution feeding system, cobalt salt solution feeding system, manganese or aluminum salt solution feeding system, complexing agent feeding system, and precipitant feeding system are independently connected in parallel with the reactor. The DCS control system is independently connected to each of the nickel salt solution feeding system, cobalt salt solution feeding system, manganese or aluminum salt solution feeding system, complexing agent feeding system, and precipitant feeding system via signal interlocking. The online monitoring unit is located between the reactor and the DCS control system, and the online monitoring unit is connected to the DCS control system via signal interlocking.

2. The ternary precursor preparation system as described in claim 1, characterized in that, Each of the nickel salt solution feeding system, cobalt salt solution feeding system, manganese or aluminum salt solution feeding system, complexing agent feeding system, precipitant feeding system, and reactor is equipped with an independent feed pump.

3. The ternary precursor preparation system as described in claim 1, characterized in that, A filter is installed between the online monitoring unit and the reactor.

4. The ternary precursor preparation system as described in claim 3, characterized in that, A discharge pump is installed between the filter and the reactor.

5. The ternary precursor preparation system as described in claim 1, characterized in that, The online monitoring unit includes a sampling unit, a transmission unit, a sample management unit, and an analysis unit connected in series.

6. The ternary precursor preparation system as described in claim 5, characterized in that, The analysis unit is equipped with a data acquisition-processing-transmission module, a circulating cooling water module, a sample injection module, a reagent refrigeration module, and an online analyzer.

7. The ternary precursor preparation system as described in claim 6, characterized in that, The online analyzer includes an ICP-OES analyzer or an ICP-MS analyzer.

8. A method for preparing a ternary precursor, characterized in that, The preparation method uses the ternary precursor preparation system as described in any one of claims 1-7, and the preparation method includes the following steps: Nickel salt solution, cobalt salt solution, manganese or aluminum salt solution, complexing agent and precipitant are injected into the reactor in parallel to carry out co-precipitation reaction; The alkalinity, ammonia concentration, and concentration of various metal ions in the supernatant of the reactor are monitored in real time by the online monitoring unit to obtain online monitoring data. The online monitoring data is input into the DCS control system. The DCS control system controls the nickel salt solution feeding system, cobalt salt solution feeding system, manganese or aluminum salt solution feeding system, complexing agent feeding system, and precipitant feeding system to adjust the feed rate of each material, so as to achieve precise control of the nickel, cobalt, manganese / aluminum ratio in the product.

9. The preparation method according to claim 8, characterized in that, The complexing agent includes ammonia.

10. The preparation method according to claim 8, characterized in that, The precipitant includes a sodium hydroxide solution.

11. The preparation method according to claim 8, characterized in that, The reactor contains a bottom liquid.

12. The preparation method according to claim 11, characterized in that, The base liquid includes ammonia and alkaline solution.

13. A ternary precursor, characterized in that, The ternary precursor is prepared by the method described in any one of claims 8-12.

14. The ternary precursor as described in claim 13, characterized in that, The deviation in the proportion of metal elements in the ternary precursor is ≤0.10 mol.

15. A positive electrode material, characterized in that, The cathode material is prepared by sintering the ternary precursor as described in claim 13 or 14 with a lithium source.

16. A lithium-ion battery, characterized in that, The lithium-ion battery comprises the positive electrode material as described in claim 15.

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