阅读说明：本技术 一种金属钒酸盐化合物共掺杂的高镍三元前驱体及其制备方法 (Metal vanadate compound co-doped high-nickel ternary precursor and preparation method thereof ) 是由 张宝 王振宇 于 2020-05-15 设计创作，主要内容包括：本发明提出了一种金属钒酸盐化合物共掺杂的高镍三元前驱体及其制备方法。在共沉淀反应过程中掺杂金属钒酸盐化合物,实现一种或两种以上金属协同掺杂改性镍、钴以及锰或铝三元前驱体材料；在制备过程中,将络合剂溶液和金属溶液均分为上下两根进液管加入至反应釜内,在前驱体生长的不同阶段采用不同的调控方式和生长工艺参数,可制备出具有花片状、细长纺锤状、粗短棒状等特殊一次颗粒形貌的或内部疏松多孔、密实、空心等剖面形貌的三元前驱体,能满足不同性能的锂电池对不同物理性能的前驱体的需求。(The invention provides a metal vanadate compound co-doped high-nickel ternary precursor and a preparation method thereof. Doping a metal vanadate compound in the coprecipitation reaction process to realize that one or more than two metals are synergistically doped with modified nickel, cobalt and manganese or aluminum ternary precursor materials; in the preparation process, the complexing agent solution and the metal solution are equally divided into an upper liquid inlet pipe and a lower liquid inlet pipe to be added into a reaction kettle, different regulation and control modes and growth process parameters are adopted in different stages of the precursor growth, so that the ternary precursor with special primary particle shapes such as a flower sheet shape, a slender spindle shape, a thick rod shape, a short rod shape and the like or section shapes such as loose porosity, compactness, hollowness and the like can be prepared, and the requirements of lithium batteries with different performances on the precursors with different physical performances can be met.)

1. A high nickel ternary precursor codoped by a metal vanadate compound is characterized in that the high nickel ternary precursor is a material codoped with vanadium and other alkali metals or transition metal ions uniformly or in a concentration gradient; the high-nickel ternary precursor or the primary particles are in a flower sheet shape, a slender spindle shape or a thick rod shape, or the section shape is a loose porous, compact or hollow type; the alkali metal or transition metal ions are selected from one or more of Mg, W, Mo, Ag, Cu, Zr, La, Bi, Sn, Y and Sr.

2. A method of making the high nickel ternary precursor of claim 1, comprising the steps of:

(1) preparing a solution:

preparing a complexing agent solution A and a precipitator solution B; preparing a metal salt solution C of nickel, cobalt, manganese or aluminum according to the molar ratio of nickel, cobalt, manganese or aluminum in the high-nickel ternary precursor; preparing a soluble vanadium salt solution D and a soluble co-doped metal salt solution E;

(2) preparing a reaction kettle bottom liquid F:

adding distilled water, a complexing agent solution A and a precipitator solution B into a reaction kettle to prepare a reaction kettle bottom solution F;

(3) coprecipitation reaction:

adding the solution prepared in the step (1) into the reaction kettle bottom solution F in the step (2), and carrying out coprecipitation reaction in a reaction kettle;

it is characterized in that the preparation method is characterized in that,

adding a complexing agent solution A and a metal salt solution C into the reaction kettle through an upper liquid inlet pipe and a lower liquid inlet pipe respectively;

during the coprecipitation reaction, the initial set flow values of the metal salt solution C, the vanadium salt solution D and the co-doped metal salt solution E are kept unchanged, and then the uniformly doped high-nickel ternary precursor material is prepared;

during the coprecipitation reaction, the flow rates of the vanadium salt solution D and the co-doped metal salt solution E are increased at a constant speed, and then the high-nickel ternary precursor material doped with the concentration gradient is prepared;

and (3) adopting a one-step or two-step regulation and control mode, and regulating and controlling parameters such as stirring rotating speed, reaction temperature, pH value, concentration of a complexing agent, solid content, reaction time and the like in the reaction process to prepare the high-nickel ternary precursor with different morphologies.

3. The preparation method according to claim 2, characterized by preparing a high nickel ternary precursor with a compact cross-sectional morphology or a high nickel ternary precursor with a primary particle morphology in a flower-sheet shape, a slender spindle shape or a thick-short rod shape in a one-step regulation manner; a high-nickel ternary precursor with a loose, porous or hollow profile is prepared in a two-step regulation mode.

4. The preparation method according to claim 2 or 3, wherein the process parameters of the coprecipitation reaction in step (3) are adjusted as follows: the pH value is 11.5-12.8, the concentration of a complexing agent is controlled to be 6.0-8.0 g/L, the stirring speed is 600-1000 rpm, the reaction temperature is 55-75 ℃, the clear content of a precision filter is adjusted to enable the solid content to be 600-900 g/L, nitrogen is introduced, the nitrogen flow is 100-600L/min, and then the high-nickel ternary precursor with the compact profile morphology structure is prepared.

5. The preparation method according to claim 2 or 3, wherein the process parameters of the coprecipitation reaction in step (3) are adjusted as follows: the pH value is 11.5-12.3, the concentration of a complexing agent is controlled to be 8.0-13.0 g/L, the stirring speed is 450-800 rpm, the reaction temperature is 63-75 ℃, the clear volume of a precision filter is adjusted to ensure that the solid content is 350-750 g/L, the oxygen content in a reaction kettle is 0.5-1.0%, and the gas flow is 30-80L/min, so that a high-nickel ternary precursor with a coarse-short rod-shaped primary particle morphology is prepared;

the gas is a mixed gas of oxygen and nitrogen, wherein the concentration of the oxygen is 0-10%.

6. The preparation method according to claim 2 or 3, wherein the process parameters of the coprecipitation reaction in step (3) are adjusted as follows: the pH value is 10.6-11.8, the concentration of a complexing agent is controlled to be 10.0-14.0 g/L, the stirring speed is controlled to be 250-420 rpm, the reaction temperature is 50-70 ℃, preferably 55-62 ℃, the clear volume of a precision filter is adjusted to enable the solid content to be 250-380 g/L, the oxygen content in a reaction kettle is 1.5-5.0%, and the gas flow is 20-80L/min, so that the high-nickel ternary precursor with the shape of primary particles being in a flower sheet shape is prepared;

the gas is a mixed gas of oxygen and nitrogen, wherein the concentration of the oxygen is 0-10%.

7. The preparation method according to claim 2 or 3, wherein the process parameters of the coprecipitation reaction in step (3) are adjusted as follows: the pH value is 11.5-12.6, the concentration of a complexing agent is controlled to be 6.0-8.0 g/L, the stirring speed is 650-1000 rpm, the reaction temperature is 60-75 ℃, the clear volume of a precision filter is adjusted to enable the solid content to be 500-900 g/L, nitrogen is introduced, the nitrogen flow is 30-200L/min, and then the high-nickel ternary precursor with the slender spindle-shaped primary particle morphology is prepared.

8. The production method according to claim 2 or 3, wherein the coprecipitation reaction of step (3) is divided into two steps:

firstly, the parameters of the coprecipitation reaction process are controlled as follows: regulating and controlling the reaction pH to be 11.8-13.0, controlling the concentration of a complexing agent to be 8.0-10.0 g/L, controlling the oxygen content in the reaction kettle to be 0.8-1.5%, controlling the gas flow to be 50-200L/min, controlling the stirring speed to be 200-600 rpm, controlling the reaction temperature to be 55-75 ℃ and controlling the reaction time to be 6-10 h;

then, the parameters of the coprecipitation reaction process are adjusted as follows: controlling the oxygen content to be 0.1-0.9%, the reaction pH to be 11.5-12.0, the stirring speed to be 400-900 rpm, adjusting the clear volume of a precision filter to ensure that the solid content is 400-700 g/L, and the reaction time to be 40-80 h;

preparing a high-nickel ternary precursor with a loose porous morphology structure;

the gas is a mixed gas of oxygen and nitrogen, and the concentration of the oxygen is 0-10%.

9. The production method according to claim 2 or 3, wherein the coprecipitation reaction of step (3) is divided into two steps:

firstly, the parameters of the coprecipitation reaction process are controlled as follows: the reaction pH is 11.0-11.8, the concentration of a complexing agent is controlled to be 8.0-13.0 g/L, the oxygen content in the reaction kettle is 1% -3%, the gas flow is 70-200L/min, the stirring speed is 200-600 rpm, the reaction temperature is 45-65 ℃, and the reaction time is 8-15 hours;

then, the parameters of the coprecipitation reaction process are adjusted as follows: controlling the oxygen content in the reaction kettle to be 0.1-0.9%, stirring at a speed of 400-900 rpm, adjusting the clear volume of the precision filter to enable the solid content to be 400-700 g/L, and reacting for 50-90 hours;

preparing a high-nickel ternary precursor with a hollow shell type profile morphology structure;

the gas is a mixed gas of oxygen and nitrogen, and the concentration of the oxygen is 0-10%.

10. The preparation method according to claim 2 or 3, characterized in that in the coprecipitation reaction process in the step (3), a batch or concentration process can be adopted, and when the volume of the reaction kettle bottom liquid is 1/6-2/3 of the volume of the reaction kettle, a batch concentration process is preferably adopted; when the volume of the bottom liquid of the reaction kettle is 2/3-1 of the volume of the reaction kettle, a continuous concentration process is preferably adopted.

11. The preparation method according to claim 2, wherein a stirring paddle device is arranged in the reaction kettle, the stirring paddles are arranged as an upper layer stirring paddle and a lower layer stirring paddle, upper end feed ports for conveying the complexing agent solution A and the metal salt solution C, feed ports for the precipitant solution B, the vanadium salt solution D and the co-doped metal salt solution E and the upper layer stirring paddle are located at the same horizontal position, lower end feed pipes for conveying the complexing agent solution A and the metal salt solution C and the lower layer stirring paddle are located at the same horizontal position, and the flow ratio of the solution in the upper feed pipe and the lower feed pipe of the complexing agent solution A is 1: (0.1-8), the flow ratio of the solution in the upper liquid inlet pipe and the lower liquid inlet pipe of the metal salt solution C is 1: (0.1 to 12).

12. The preparation method according to claim 2 or 11, wherein during the coprecipitation reaction in the step (3), the total feed flow rate of the complexing agent solution A is 4-50 mL/min, the feed flow rate of the precipitant solution B is 4-100 mL/min, and the total feed flow rate of the metal salt solution C is 20-200 mL/min.

13. The preparation method according to claim 2, wherein in the step (2), the initial pH of the reaction kettle bottom liquid F is 11-13; the concentration of the complexing agent in the bottom liquid F of the reaction kettle is 6-15 g/L; the volume of the reaction kettle bottom liquid F is 1/6-1 of the volume of the reaction kettle.

14. The production method according to claim 2,

in the step (1), further performing filter pressing on a metal salt solution C to a salt storage tank for constant-temperature storage, wherein the storage temperature is 30-70 ℃;

in the step (1), further performing temperature-controlled preservation on the vanadium salt solution D, wherein the preservation temperature is 30-90 ℃;

in the step (1), the co-doped metal is alkali metal or transition metal, and the concentration of the co-doped metal ions in the co-doped metal salt solution E is 0.01-3.0 mol/L; the alkaline metal or transition metal soluble salt is at least one of Mg, W, Mo, Ag, Cu, Zr, La, Bi, Sn, Y and Sr salts.

15. The production method according to claim 2,

in the step (1), the concentration of the precipitant solution B is 4-15 mol/L; the concentration of the complexing agent solution A is 5-14 mol/L; the precipitant is NaOH, KOH, Ba (OH)₂、Na₂CO₃Or LiOH; the complexing agent is at least one of ammonia water, ethylenediamine and ethylenediamine tetraacetic acid;

in the step (1), the total concentration of metal ions in the metal salt solution C is 0.8-5.0 mol/L; the nickel salt, the cobalt salt and the manganese salt are at least one of sulfate, acetate, halogen salt or nitrate; the aluminum salt is at least one of aluminum nitrate, aluminum carbonate, aluminum sulfate or sodium metaaluminate;

in the step (1), the concentration of vanadium ions in the vanadium salt solution D is 0.01-3.0 mol/L; the vanadium salt is at least one of soluble vanadium salts such as vanadium pentoxide or ammonium metavanadate, sodium metavanadate, potassium metavanadate, sodium orthovanadate, sodium pyrovanadate and the like.

Technical Field

The invention belongs to the technical field of lithium ion batteries, relates to a ternary precursor of a lithium ion battery anode material and a preparation method thereof, and particularly relates to a high-nickel ternary precursor co-doped with a metal vanadate compound and a preparation method thereof.

Background

High nickel layered transition metal oxides are currently one of the most promising positive electrode materials for lithium ion batteries, such as LiNi_1-x-yMn_xCo_yO₂(NCM) and LiNi_1-x-yCo_xAl_yO₂(NCA) has attracted considerable interest to researchers in the industry and academia. Nickel (Ni) is a substitute for cobalt (Co) in high nickel anodes, and has a magnetoresistance effect. Upon discharge, Li⁺The mixed lithium-nickel composite oxide can be mixed into a nickel layer to form Li-Ni mixed rows instead of being only stored between oxide layers, so that the high-nickel ternary precursor positive electrode material has high capacity, and the problems of poor cycle performance, rate performance and thermal stability, NCA battery flatulence and the like cannot be solved. In order to obtain the ternary cathode material with good cycle performance, high capacity, good rate capability and low price, the performance of the ternary precursor is improved at first.

At present, Mg, Al, Zr, Ti, W, F, V, La, Ce, Y and other elements are mostly adopted to dope and modify a precursor, and doped ions participate in compensating charges, so that phase change can be inhibited, polarization is lightened, capacity retention performance is improved, side reaction between an electrode and electrolyte is reduced, the working voltage of a lithium ion battery is stably improved, and the energy density of the battery is increased; the distance between the layered structures can be increased, and the multiplying power is improved; the structure of the precursor can be stabilized, so that the thermal stability, safety and cycle performance of the anode material are improved, and the research is widely carried out. The relatively stable structures of vanadate compounds are generally layered compounds of the general formula Me_xV_yO_zMe is an alkali metal and a transition metal ion, such as Mg, W, Mo, Ag, Cu, Zr, La, Bi, Sn, Y, Sr and the like, such vanadate materials are often used as supercapacitor electrode materials, and due to the characteristic that multivalent vanadium ions can be reduced in multiple steps in the process of embedding and extracting lithium ions and the fact that metal ions are additionally introduced into the structure, corresponding optimization effects (such as a supporting column effect or a self-maintenance effect and the like) can be generated, high specific capacitance, good cycle and rate performance, electrochemical impedance and electrochemical impedance can be generally shownLow. The preparation method and related research work of the metal vanadate compound serving as the lithium ion cathode active material are rarely reported at present.

In addition, the mainstream feeding mode of the nickel-cobalt-manganese ternary precursor at present is to inject materials such as salt, alkali and ammonia into a reaction system from the upper end of a reaction kettle by adopting a single liquid inlet pipe, so that the materials are easily mixed unevenly, local metal ions are supersaturated and have high pH value, and a large amount of crystal nuclei (or tiny particles) are generated, so that D is generated in the synthesis process_minLess than 1 μm, which causes the normal distribution of the size particles of the product prepared by the continuous method, aggravates the material loss of filter cloth penetration or air draft separation during drying in the washing process, and easily causes the overburning phenomenon in the later sintering process.

The patent with the publication number of CN105280898A discloses a vanadium-doped nickel-cobalt-manganese oxide nano material and a preparation method and application thereof. The method adopts a coprecipitation method combined with a solid-phase sintering method process, firstly synthesizes nickel-cobalt-manganese hydroxide through the coprecipitation method, grinds a mixture of a presintered precursor, a vanadium source and a lithium source, and then calcines and cools. Although the method can successfully dope vanadium, the grinding of large-particle solid into micron-sized or nano-sized particles requires precise machines and processes, the process is complex, the preparation cost is high, and the uniform doping of vanadium is difficult to realize by grinding and mixing.

The patent with publication number CN105895894A discloses a preparation method of a copper vanadate material and an application of the material in a lithium ion battery as an electrode material, wherein the copper vanadate material is prepared by performing ionic liquid thermal synthesis on vanadium pentoxide or metavanadate and copper salt in ionic liquid or a low-melting mixture and other solvents. Due to its layered structure and multi-step reduction during intercalation or deintercalation of lithium ions (Cu)²⁺/Cu⁺And Cu⁺/Cu⁰) The prepared flaky or flower-shaped copper vanadate material has extremely limited application in the positive electrode material of the lithium ion battery.

Disclosure of Invention

The invention aims to overcome the defects in the prior art, provides a wet synthesis co-doped one or more than two metal modified nickel, cobalt and manganese or aluminum ternary precursor material and a preparation method thereof, and realizes the synthesis of a controllable-morphology and controllable-metal vanadate compound co-doped high-nickel ternary precursor by a wet one-step method.

To solve the above technical problem, the present invention provides the following solutions.

A high nickel ternary precursor codoped by a metal vanadate compound is characterized in that the high nickel ternary precursor is a material codoped with vanadium and other alkali metals or transition metal ions uniformly or in a concentration gradient; the high-nickel ternary precursor or the primary particles are in a flower sheet shape, a slender spindle shape or a thick rod shape, or the section shape is a loose porous, compact or hollow type; the alkali metal or transition metal ions are selected from one or more of Mg, W, Mo, Ag, Cu, Zr, La, Bi, Sn, Y and Sr.

A preparation method of the metal vanadate compound co-doped high-nickel ternary precursor comprises the following steps:

(1) preparing a solution:

preparing a complexing agent solution A and a precipitator solution B; preparing a metal salt solution C of nickel, cobalt, manganese or aluminum according to the molar ratio of nickel, cobalt, manganese or aluminum in the high-nickel ternary precursor; preparing a soluble vanadium salt solution D and a soluble co-doped metal salt solution E;

(2) preparing a reaction kettle bottom liquid F:

adding distilled water, a complexing agent solution A and a precipitator solution B into a reaction kettle to prepare a reaction kettle bottom solution F;

(3) coprecipitation reaction:

adding the solution prepared in the step (1) into the reaction kettle bottom solution F in the step (2), and carrying out coprecipitation reaction in a reaction kettle to prepare the high-nickel ternary precursor;

it is characterized in that the preparation method is characterized in that,

adding a complexing agent solution A and a metal salt solution C into the reaction kettle through an upper liquid inlet pipe and a lower liquid inlet pipe respectively;

during the coprecipitation reaction, the initial set flow values of the metal salt solution C, the vanadate solution D and the co-doped metal salt solution E are kept unchanged, so that the vanadate uniformly doped high-nickel ternary precursor material can be obtained;

during the coprecipitation reaction, the flow rates of the vanadium salt solution D and the co-doped metal salt solution E are increased at a constant speed, and then the high-nickel ternary precursor material doped with the concentration gradient is prepared;

and (3) adopting a one-step or two-step regulation and control mode, and regulating and controlling parameters such as stirring rotating speed, reaction temperature, pH value, concentration of a complexing agent, solid content, reaction time and the like in the reaction process to prepare the high-nickel ternary precursor with different morphologies.

Further, a high-nickel ternary precursor with a compact cross section or a high-nickel ternary precursor with a primary particle shape of a flower sheet shape, a slender spindle shape or a thick rod shape is prepared in a one-step regulation mode; a high-nickel ternary precursor with a loose, porous or hollow profile is prepared in a two-step regulation mode.

Further, preparing a high-nickel ternary precursor with a compact profile morphology structure, and regulating and controlling the process parameters of the coprecipitation reaction in the step (3) as follows: the pH value is 11.5-12.8, preferably 12.0-12.6; the concentration of the complexing agent is controlled to be 6.0-8.0 g/L, preferably 6.5-7.5 g/L; the stirring speed is 600-1000 rpm, preferably 700-900 rpm; the reaction temperature is 55-75 ℃, and preferably 60-70 ℃; adjusting the clear volume of the precision filter to ensure that the solid content is 600-900 g/L, preferably 750-850 g/L; introducing nitrogen with the flow rate of 100-600L/min, preferably 100-400L/min.

Further, preparing a high-nickel ternary precursor with a coarse-short rod-shaped primary particle morphology, and regulating and controlling the technological parameters of the coprecipitation reaction in the step (3) as follows: the pH value is 11.5-12.3, preferably 11.8-12.0; the concentration of the complexing agent is controlled to be 8.0-13.0 g/L, preferably 10.0-12.0 g/L; the stirring speed is 450-800 rpm, preferably 500-650 rpm; the reaction temperature is 63-75 ℃, preferably 65-72 ℃; adjusting the clear volume of the precision filter to ensure that the solid content is 350-750 g/L, preferably 450-700 g/L; the oxygen content in the reaction kettle is 0.5-1.0%, and the gas flow is 30-80L/min, preferably 35-60L/min. The gas is oxygen and nitrogen, and the concentration of the oxygen is 0-10%, preferably 0-4%.

Further, preparing a high-nickel ternary precursor with a flower-shaped primary particle morphology, and regulating and controlling the technological parameters of the coprecipitation reaction in the step (3) as follows: the pH value is 10.6-11.8, preferably 11.0-11.5; the concentration of the complexing agent is controlled to be 10.0-14.0 g/L, preferably 11.5-12.8 g/L; controlling the stirring speed to be 250-420 rpm, preferably 320-400 rpm; the reaction temperature is 50-70 ℃, and preferably 55-62 ℃; adjusting the clear volume of the precision filter to enable the solid content to be 250-380 g/L; the oxygen content in the reaction kettle is 1.5-5.0%, and the gas flow is 20-80L/min, preferably 25-50L/min. The gas is oxygen and nitrogen, and the concentration of the oxygen is 0-10%, preferably 0-4%.

Further, preparing a high-nickel ternary precursor with a primary particle shape of a slender spindle, and regulating and controlling the technological parameters of the coprecipitation reaction in the step (3) as follows: the pH value is 11.5-12.6, preferably 11.8-12.4; the concentration of the complexing agent is controlled to be 6.0-8.0 g/L, preferably 6.5-7.5 g/L; the stirring speed is 650-1000 rpm, preferably 700-850 rpm; the reaction temperature is 60-75 ℃, preferably 63-68 ℃; adjusting the clear volume of the precision filter to ensure that the solid content is 500-900 g/L, preferably 550-700 g/L; introducing nitrogen with the flow rate of 30-200L/min, preferably 50-150L/min.

Further, a high-nickel ternary precursor with a loose porous morphology structure is prepared, and the coprecipitation reaction in the step (3) is divided into two steps: firstly, regulating and controlling the reaction pH to be 11.8-13.0, preferably 12.0-12.4; the concentration of the complexing agent is controlled to be 8.0-10.0 g/L, preferably 8.2-9.5 g/L; the oxygen content in the reaction kettle is 0.8-1.5%, and the gas flow is 50-200L/min; the stirring speed is 200-600 rpm, preferably 300-400 rpm; the reaction time is 6-10 h; the reaction temperature is 55-75 ℃, and preferably 60-70 ℃; then, controlling the oxygen content to be 0.1-0.9%; the reaction pH is 11.5-12.0, preferably 11.6-11.9; the stirring speed is 400-900 rpm, preferably 480-600 rpm; adjusting the clear volume of the precision filter to ensure that the solid content is 400-700 g/L, preferably 450-650 g/L; the reaction time is 40-80 h, preferably 45-60 h. The gas is oxygen and nitrogen, and the concentration of the oxygen is 0-10%, preferably 0-4%.

Further, a high-nickel ternary precursor with a hollow shell type profile morphology structure is prepared, and the coprecipitation reaction in the step (3) is divided into two steps: firstly, controlling the reaction pH to be 11.0-11.8, preferably 11.2-11.5; the concentration of the complexing agent is controlled to be 8.0-13.0 g/L, preferably 10.0-12.0 g/L; the oxygen content in the reaction kettle is 1% -3%, and the gas flow is 70-200L/min; the stirring speed is 200-600 rpm, preferably 300-400 rpm; the reaction time is 8-15 h; the reaction temperature is 45-65 ℃, and preferably 50-65 ℃; then, controlling the oxygen content in the reaction kettle to be 0.1-0.9%; the stirring speed is 400-900 rpm, preferably 400-560 rpm; adjusting the clear volume of the precision filter to ensure that the solid content is 400-700 g/L, preferably 450-650 g/L; the reaction time is 50-90 h, preferably 52-85 h. The gas is oxygen and nitrogen, and the concentration of the oxygen is 0-10%, preferably 0-4%.

Furthermore, in the coprecipitation reaction process in the step (3), an intermittent or concentration process can be adopted, and when the volume of the reaction kettle bottom liquid is 1/6-2/3 of the volume of the reaction kettle, the intermittent concentration process is preferably adopted; when the volume of the bottom liquid of the reaction kettle is 2/3-1 of the volume of the reaction kettle, a continuous concentration process is preferably adopted.

Further, in the step (1), the concentration of the precipitant solution B is 4-15 mol/L, preferably 10-13 mol/L; the concentration of the complexing agent solution A is 5-14 mol/L, and preferably 6-13 mol/L.

Further, in the step (1), the precipitant is NaOH, KOH, Ba (OH)₂、Na₂CO₃Or LiOH; the complexing agent is at least one of ammonia water, ethylenediamine and ethylenediamine tetraacetic acid.

Further, in the step (1), the total concentration of metal ions in the metal salt solution C is 0.8-5.0 mol/L, preferably 1.5-3.5 mol/L; the nickel salt, the cobalt salt and the manganese salt are at least one of sulfate, acetate, halogen salt or nitrate; the aluminum salt is at least one of aluminum nitrate, aluminum carbonate, aluminum sulfate or sodium metaaluminate.

Further, carrying out filter pressing on the metal salt solution C to a salt storage tank for constant-temperature storage; the preservation temperature is 30-70 ℃, and preferably 40-50 ℃.

Further, in the step (1), the concentration of vanadium ions in the vanadium salt solution D is 0.01-3.0 mol/L, preferably 0.1-2.0 mol/L. The vanadium salt is at least one of soluble vanadium salts such as vanadium pentoxide or ammonium metavanadate, sodium metavanadate, potassium metavanadate, sodium orthovanadate, sodium pyrovanadate and the like.

Further, the vanadium salt solution D is stored at a controlled temperature, wherein the storage temperature is 30-90 ℃, and preferably 40-60 ℃.

Further, in the step (1), the co-doped metal is alkali metal or transition metal, and the concentration of the co-doped metal ions in the co-doped metal salt solution E is 0.01-3.0 mol/L, preferably 0.1-2.0 mol/L; the alkaline metal or transition metal soluble salt is at least one of Mg, W, Mo, Ag, Cu, Zr, La, Bi, Sn, Y and Sr salts.

Further, in the step (2), the initial pH of the reaction kettle bottom liquid F is 11-13, preferably 11.5-12.5; the concentration of the complexing agent in the bottom liquid F of the reaction kettle is 6-15 g/L, preferably 6-10 g/L; the volume of the reaction kettle bottom liquid F is 1/6-1, preferably 1/4-1 of the volume of the reaction kettle.

Further, the flow ratio of the solution in the upper liquid inlet pipe and the lower liquid inlet pipe of the complexing agent solution A is 1: (0.1-8), the flow ratio of the solution in the upper liquid inlet pipe and the lower liquid inlet pipe of the metal salt solution C is 1: (0.1 to 12).

Further, in the coprecipitation reaction process in the step (3), the total feed flow rate of the complexing agent solution A is 4-50 mL/min, the feed flow rate of the precipitant solution B is 4-100 mL/min, and the total feed flow rate of the metal salt solution C is 20-200 mL/min.

Further, set up the stirring rake device in the reation kettle, the stirring rake sets up to upper stirring rake and lower floor's stirring rake, and the upper end feed inlet of carrying complexing agent solution A, metal salt solution C and precipitant solution B, vanadium salt solution D, the feed inlet of codoping metal salt solution E and upper stirring rake are located same horizontal position, and the lower extreme inlet pipe of carrying complexing agent solution A, metal salt solution C and lower floor's stirring rake are located same horizontal position.

Further, the slurry obtained by the coprecipitation reaction in the step (3) is aged, washed, filtered, dried, sieved and deironized, wherein the aging time is 5-20 hours, preferably 6-15 hours, the temperature of the washed deionized water is 50-90 ℃, the drying temperature is 100-300 ℃, the drying time is 10-20 hours, and the sieving screen is a 100-400-mesh screen, preferably a 200-mesh screen.

The invention adopts a simple and feasible coprecipitation synthesis mode, and one or more metal vanadate compounds (Me) are directly doped in the step of preparing the ternary precursor by a wet method_xV_yO_zMe is alkaline metal and transition metal ions, such as Mg, W, Mo, Ag, Cu, Zr, La, Bi, Sn, Y, Sr and the like), and one or more than two metal ions are synergistically doped to modify the ternary precursor material of nickel, cobalt and manganese or aluminum; in the preparation process, complexing agents with different concentrations are adopted according to the preparation requirements of the high-nickel ternary precursor and the morphology thereof, a complexing agent solution and a metal salt solution are equally divided into an upper liquid inlet pipe and a lower liquid inlet pipe which are connected in parallel to a reaction kettle, and NH is utilized₃The metal ion saturation degree in the reaction system is regulated and controlled by the complexation with the metal ions, thereby controlling the reaction nucleation and the crystal growth rate of the precursor, obviously reducing crystal nucleus, and improving D_minFurther improve the product yield and realize cost reduction and efficiency improvement; secondly, the growth of precursor particles is controlled by regulating and controlling process parameters of each stage of the intermittent or concentrated process, so that the prepared precursor has a high-nickel ternary precursor with special primary particle morphology (such as a flower sheet shape, a slender spindle shape and a thick-short rod shape) or section morphology (such as loose, porous, compact and hollow interior), and the problems of poor cycle multiplying power and thermal stability of the conventional high-nickel anode material and the problem of gas expansion of an NCA battery are solved.

The principle of the invention is as follows:

firstly, in the preparation process, complexing agents with different concentrations are adopted according to the preparation requirements of a high-nickel ternary precursor and the shape of the high-nickel ternary precursor, and a complexing agent solution and a metal salt solution are uniformly divided into an upper liquid inlet pipe and a lower liquid inlet pipe which are connected in parallel to a reaction kettle, so that a large number of transition metal ions exist in the form of ammonia complexes after being added into the reaction kettle, the free transition metal ions are reduced, and the reaction kettle is prevented from being pollutedToo high saturation of internal local metal ions by NH₃The metal ion saturation in the reaction system is regulated and controlled by the complexation with the metal ions, so that the precursor reaction nucleation is controlled, more precipitated ions in the solution are diffused to the surface of crystal nucleus particles and are precipitated on the surface of the crystal nucleus, the crystal grain growth is promoted, the crystal nucleus can be obviously reduced, and the D is improved_minThe material loss of air draft separation during the filtration and drying of the filter cloth in the washing process is reduced, the cost is reduced and the effect is improved; secondly, adding soluble vanadate and metal salt into a reaction kettle, wherein the soluble vanadate is easy to hydrolyze in a reaction system to generate vanadate radicals, and on one hand, the vanadate radicals can not only realize coprecipitation with nickel-cobalt-manganese ions to generate vanadate compound precipitates (nickel vanadate, manganese vanadate and cobalt vanadate); on the other hand, vanadate can be formed by binding vanadate to a basic metal, transition metal ion or hydroxide thereof such as Mg, W, Mo, Ag, Cu, Zr, La, Bi, Sn, Y, Sr, etc. Therefore, the precipitation of vanadium, alkali metal or transition metal ions can be carried out in-situ precipitation in the ternary precursor without adding a new precipitator, and the synergistic doping modification of one or more than two metals on the nickel, cobalt and manganese or aluminum ternary precursor material is realized.

The invention adopts an intermittent or continuous concentration process, and ensures the precursor to have narrow particle size distribution, good sphericity and uniform size. In addition, the stirring speed is properly increased, so that the angular deformation speed and the shear stress of fluid (precursor slurry) in the reaction kettle can be increased, the collision strength among particles is enhanced, the particle agglomeration and the morphology of primary particles and secondary particles are further improved, and the tap density of the precursor is increased; NH of nickel-cobalt-manganese metal ion capable of being mixed with complexing agent₄ ⁺Formation of complexes, modification of Ni²⁺、Co²⁺、Mn²⁺The coprecipitation rate can control the appearance of primary particles of the nickel-cobalt-manganese metal hydroxide through the concentration of a complexing agent, and the appearance of the primary particles can be in a flower-shaped sheet shape, a slender spindle shape, a thick rod shape and a short rod shape along with the increase of the concentration of the complexing agent; the stacking growth mode of the precursor secondary particles can be controlled by regulating and controlling the pH value in the reaction process, so that a ternary precursor with a loose, porous or compact section appearance is obtained; also by setting a precision filterThe solid content of the slurry in the kettle is adjusted by the clear volume, so that the structure of the precursor is gradually changed from loose to compact. In the reaction process, the technological parameters such as stirring speed, reaction temperature, reaction pH value, concentration of complexing agent in the reaction kettle, atmosphere in the kettle, solid content, reaction time and the like are strictly and stably controlled, and the high-nickel ternary precursor co-doped with the shape-controllable metal vanadate compound can be obtained through the procedures of reaction, aging, washing, drying and iron removal.

The invention has the following beneficial effects:

the invention equally divides the complexing agent solution and the metal solution into an upper liquid inlet pipe and a lower liquid inlet pipe which are connected in parallel to the reaction kettle, avoids overhigh saturation of local metal ions in the reaction kettle, controls the nucleation rate of the precursor reaction, and improves D_minAnd production line yield; and simultaneously, one or more than two metals are synthesized into one-step ternary precursor materials of nickel, cobalt and manganese or aluminum through wet method, and the vanadate compound has the characteristics of a layered crystal structure for lithium removal/lithium insertion and metal carrying, and is beneficial to reducing residual lithium, thinning SEI film thickness formed by side reaction between an electrode and an electrolyte, and inhibiting phase transition and mechanical degradation of particles. By adjusting the growth process parameters of the precursor, high-nickel ternary precursors with different primary particles or section structure appearances and ternary precursors with different primary particle appearances can be prepared, and different Li is contained in the sintering process⁺The heat propagation path can reduce Li/Ni cation mixed row and Li to different degrees⁺Diffusion coefficient D_Li ⁺(ii) a The loose porous section is in the shapes of a stress diffusion area and a lithium ion rapid conduction layer, and is beneficial to relieving micro stress generated by crystal transformation in a long-period process and accelerating the migration of charges and lithium ions; the compact structure type section morphology effectively avoids structural collapse caused by phase change, and ensures the integrity of the whole structure of the material; the anode material prepared by calcining the ternary precursor rich in lithium has the advantages of high specific capacitance, good structural stability, capacitance retention rate and rate capability, low electrochemical impedance and the like, solves the problems of poor cycle rate capability and thermal stability of the high-nickel ternary anode material and gas expansion of an NCA (negative temperature coefficient) battery, and can meet the requirements of lithium batteries with different performances on different objectsThe requirement of precursors for physical properties.

Drawings

The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate an embodiment of the invention and, together with the description, serve to explain the invention and not to limit the invention.

FIG. 1 is a SEM cross-sectional view of a V-Li co-doped NCM801010 ternary precursor prepared in example 1;

FIG. 2 is a SEM cross-section of a V-Mg co-doped NCM730918 ternary precursor prepared in example 2;

FIG. 3 is a SEM cross-section of a V-La co-doped NCM602020 ternary precursor prepared in example 3;

FIG. 4 is an SEM image of a V-Cu co-doped NCM880903 ternary precursor prepared in example 4;

FIG. 5 is an SEM image of a V-Zr co-doped NCM701020 ternary precursor prepared in example 5;

FIG. 6 is an SEM image of one of the V-doped NCM680527 ternary precursors prepared in example 6.

Detailed Description

The present invention will now be described in detail with reference to the drawings, which are given by way of illustration and explanation only and should not be construed to limit the scope of the present invention in any way. Furthermore, features from embodiments in this document and from different embodiments may be combined accordingly by a person skilled in the art from the description in this document.

The chemical reagents used in the examples of the present invention, unless otherwise specified, are commercially available in a conventional manner.