CN110668510A - Preparation method for synthesizing ternary precursor by nickel, cobalt and manganese step by step - Google Patents

Abstract

The invention relates to the technical field of battery technology, and discloses a preparation method of a ternary precursor for a lithium ion positive electrode material, which mainly controls different metal ratios in different synthesis stages of the precursor to realize the step-by-step process of nickel-cobalt-manganese ternary precursor. Precipitation, so as to realize the gradient structure of the positive electrode material element, the inner core is rich in nickel and the outer layer is rich in manganese. The positive electrode material of this structure can improve the capacity and safety performance of the lithium ion battery.

Description

A kind of preparation method of nickel-cobalt-manganese step-by-step synthesis of ternary precursor

technical field

The invention relates to the technical field of battery technology, in particular to a preparation method for synthesizing a ternary precursor of nickel, cobalt and manganese in steps.

Background technique

Among the current cathode materials for power lithium-ion batteries, nickel-cobalt lithium manganate ternary layered cathode materials, whose chemical formula is LiNi1-x-yCoxMnyO2, have high discharge specific capacity due to the synergistic effect of Ni, Co and Mn. It has the advantages of high energy density, low cost and environmental friendliness, and has become a cathode material with a huge increase in the application field of power lithium-ion batteries in the global market in recent years.

However, due to the increasing requirements for high-capacity and high-density materials for power vehicle batteries, the commonly used method is to increase the nickel content to increase the capacity, while nickel-cobalt lithium aluminate is prone to cation mixing, and Ni2+ and Li+ occupy each other. It hinders Li+ transport and destroys the crystal structure of the material, and the ability of Li+ transport between grain boundaries is poor, which causes great harm to the cycle life and capacity of the material. For this reason, we propose a Ni-Co-Mn step-by-step synthesis of three Preparation method of meta-precursor.

SUMMARY OF THE INVENTION

In view of the deficiencies of the prior art, the present invention provides a preparation method for the stepwise synthesis of ternary precursors of nickel, cobalt and manganese, which solves the problem that the nickel-cobalt aluminate is prone to cation mixing, and Ni2+ and Li+ occupy each other's space, which hinders the Li+ transmission. And destroy the crystal structure of the material, and the transfer ability of Li+ between the grain boundaries is poor, resulting in the problem of great harm to the cycle life and capacity of the material.

The present invention provides the following technical solutions: a preparation method for the step-by-step synthesis of ternary precursors of nickel, cobalt and manganese, and the specific preparation method is as follows:

The first step: preparation of nickel-cobalt binary precursor

According to the composition Ni _1-x Cox(OH) ₂ (where 0≤x≤1), the steps are as follows:

S1. The nickel source and cobalt source of the nickel-cobalt precursor are dissolved and mixed according to a fixed ratio of Ni _1-x Co _x (where 0≤x≤1), wherein the total metal molar concentration of the solution is controlled at 0.01～2mol /L;

S2. After mixing evenly, wet co-precipitation is carried out, and under the protection of nitrogen, the pH value of the reaction is controlled by adding liquid caustic soda to control the particle size of the precursor. The pH control range is between 6.5 and 13.0. At the same time, D50 2 Width and narrow control of ~20 microns;

S3. After the nickel-cobalt binary precursor is synthesized, the corresponding impurities are removed by pressure filtration or centrifugal washing, and then dried and sieved to remove iron.

The second step: preparation of nickel-cobalt-manganese ternary precursor

According to the composition Ni _1-xy Co _x M _y (OzH) ₂ (wherein 0≤x≤1, 0≤y≤1, 0≤z≤2) to prepare, the steps are as follows:

S1, slurrying the nickel-cobalt binary precursor synthesized in the first step for use;

S2. Dissolve the manganese source for later use, and control the concentration of the manganese source at 0.01-2 mol/L;

S3. After the nickel-cobalt binary precursor is slurried, the manganese and the nickel-cobalt binary precursor are compounded and synthesized, and air or oxygen is introduced to carry out the oxidation precipitation reaction. The air or oxygen is adjusted according to the feeding speed of the manganese source, and the pH is controlled. The particle size of the precursor can be controlled by the PH value, and the PH control range is between 6.5 and 13. At the same time, the width and width of D50 of 2.5 to 20 microns can be controlled by grading;

S4. After the nickel-cobalt-manganese ternary precursor is synthesized, the corresponding impurities are removed by pressure filtration or centrifugal washing, and then dried and sieved to remove iron.

The third step: post-processing process

The sintered finished products are crushed or dispersed, sieved, and iron removed, and finally packaged into finished products.

Preferably, the nickel source is mainly one or more of metal nickel, nickel sulfate and nickel chloride, the cobalt source is mainly one or more of metal cobalt, cobalt sulfate and cobalt chloride, and the manganese source is mainly manganese sulfate , one or more of manganese chloride.

Preferably, in the process of wet co-precipitation, the reaction temperature is controlled at 40°C to 80°C, the synthesis method is continuous or batch, the flow rate of the molten metal is controlled at more than 2L/min, and the ratio of ammonia to metal elements is controlled 0.05 or more.

Preferably, in the process of composite synthesis of the manganese and nickel-cobalt binary precursors, the reaction temperature is controlled at 40-80°C, the feed rate of the manganese source is controlled at more than 1L/min, and the ratio of ammonia to manganese metal elements is controlled at 0.01 above.

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

The preparation method of the nickel-cobalt-manganese ternary precursor for the step-by-step synthesis of the precursor mainly controls different metal ratios in different synthesis stages of the precursor, so as to realize the step-by-step precipitation of the nickel-cobalt-manganese ternary precursor, so as to realize the enrichment of nickel in the inner core of the positive electrode material element. The outer layer has a manganese-rich gradient structure, and the cathode material of this structure can improve both the capacity and safety performance of lithium-ion batteries.

Detailed ways

In order to make the objectives, technical solutions and advantages of the embodiments of the present disclosure clearer, the technical solutions of the embodiments of the present disclosure are described clearly and completely. Obviously, the described embodiments are some, but not all, embodiments of the present disclosure. Based on the described embodiments of the present disclosure, all other embodiments obtained by those of ordinary skill in the art without creative efforts fall within the protection scope of the present disclosure.

In order to keep the following description of the embodiments of the present disclosure clear and concise, the present disclosure omits detailed descriptions of well-known functions and well-known components to avoid unnecessarily obscuring the concepts of the present invention.

Example 1

A preparation method of nickel-cobalt-manganese stepwise synthesis of ternary precursor, the specific preparation method is as follows:

The first step: preparation of nickel-cobalt binary precursor

According to the composition Ni0.75Co.25(OH)2 (where 0≤x≤1), the steps are as follows:

S1. The nickel source and cobalt source of the nickel-cobalt precursor are dissolved and mixed according to a fixed ratio of Ni0.75Co.25 (where 0≤x≤1), and the total metal molar concentration of the solution is controlled at 2mol/L;

S2. After mixing evenly, wet co-precipitation is carried out, the reaction temperature is controlled at 50°C, the synthesis method is continuous or batch, the flow rate of the molten metal is controlled above 10L/min, the ratio of ammonia to metal elements is controlled above 0.35, and Under the protection of nitrogen, the particle size of the precursor is controlled by adding liquid alkali to control the pH value of the reaction. The pH control range is between 12.0 and the reaction is terminated when the particle size grows to 2.0-3.0 microns;

S3. After the nickel-cobalt binary precursor is synthesized, the corresponding impurities are removed by pressure filtration or centrifugal washing, and then dried and sieved to remove iron.

The second step: preparation of nickel-cobalt-manganese ternary precursor

According to the composition Ni0.6Co0.2(OH)0.8Mn0.2O0.27, the steps are as follows:

S1, slurrying the nickel-cobalt binary precursor synthesized in the first step for use;

S2. Dissolve the manganese source for later use, and control the concentration of the manganese source at 0.5mol/L;

S3. After the nickel-cobalt binary precursor is slurried, composite synthesis of manganese and nickel-cobalt binary precursor, the reaction temperature is controlled at 60 °C, the feed rate of the manganese source is controlled at 10L/min, and the ratio of ammonia to manganese metal elements is controlled at 60°C. Controlled at 0.1, the air flow was 40m³/h, and the pH value was controlled to achieve the control of the precursor particle size. The pH control range was between 6.5 and 13, and the control particle size was between 3.0 and 4.5 microns;

S4. After the nickel-cobalt-manganese ternary precursor is synthesized, the corresponding impurities are removed by pressure filtration or centrifugal washing, and then dried and sieved to remove iron packaging.

The third step: post-processing process

The sintered finished products are crushed or dispersed, sieved, and iron removed, and finally packaged into finished products.

Among them, the nickel source is mainly one or more of metal nickel, nickel sulfate and nickel chloride, the cobalt source is mainly one or more of metal cobalt, cobalt sulfate and cobalt chloride, and the manganese source is mainly manganese sulfate, One or more of manganese chloride.

Example 2

The first step: preparation of nickel-cobalt binary precursor: preparation according to the composition Ni0.88Co0.11(OH)2 (where 0≤x≤1), the steps are as follows:

S1. The nickel source and cobalt source of the nickel-cobalt precursor are dissolved and mixed according to a fixed ratio of Ni0.89Co.11 (where 0≤x≤1), wherein the total metal molar concentration of the solution is controlled at 2mol/L;

S2. After mixing evenly, wet co-precipitation is carried out. The reaction temperature is controlled at 50°C, the flow rate of the molten metal is controlled at 10L/min, and the ratio of ammonia to metal elements is controlled at 0.35. Under the protection of nitrogen, the reaction pH is controlled by adding liquid alkali. The particle size of the precursor is controlled by the value of PH value, the pH control range is between 12.0, and the reaction is terminated when the particle size grows to 2.0-3.0 microns;

S3. After the nickel-cobalt binary precursor is synthesized, the corresponding impurities are removed by pressure filtration or centrifugal washing, and then dried and sieved to remove iron.

The second step: preparation of nickel-cobalt-manganese ternary precursor: preparation according to the composition Ni0.8Co0.1(OH)0.8Mn0.1O0.13, the steps are as follows:

S1, slurrying the nickel-cobalt binary precursor synthesized in the first step for use;

S2. Dissolve the manganese source for later use, and control the concentration of the manganese source at 0.5mol/L;

S3. After the nickel-cobalt binary precursor is slurried, composite synthesis of manganese and nickel-cobalt binary precursor, the reaction temperature is controlled at 60 °C, the feed rate of the manganese source is controlled at 10L/min, and the ratio of ammonia to manganese metal elements is controlled at 60°C. Controlled at 0.1, the air flow was 40m³/h, and the pH value was controlled to achieve the control of the precursor particle size. The pH control range was between 6.5 and 13, and the control particle size was between 3.0 and 4.5 microns;

S4. After the nickel-cobalt-manganese ternary precursor is synthesized, the corresponding impurities are removed by pressure filtration or centrifugal washing, and then dried and sieved to remove iron packaging.

The third step: post-processing process

The sintered finished products are crushed or dispersed, sieved, and iron removed, and finally packaged into finished products.

Among them, the nickel source is mainly one or more of metal nickel, nickel sulfate and nickel chloride, the cobalt source is mainly one or more of metal cobalt, cobalt sulfate and cobalt chloride, and the manganese source is mainly manganese sulfate, One or more of manganese chloride.

The above embodiments are only exemplary embodiments of the present invention, and are not intended to limit the present invention, and the protection scope of the present invention is defined by the claims. Those skilled in the art can make various modifications or equivalent replacements to the present invention within the spirit and protection scope of the present invention, and such modifications or equivalent replacements should also be regarded as falling within the protection scope of the present invention.

Claims (4)

1. A preparation method for synthesizing a ternary precursor by nickel, cobalt and manganese step by step is characterized by comprising the following steps:

the first step is as follows: preparation of nickel cobalt binary precursor

According to composition Ni_1-xCox（OH）₂(wherein x is more than or equal to 0 and less than or equal to 1) by the following steps:

s1, dissolving the raw materials of nickel-cobalt precursor, namely a nickel source and a cobalt source, and then Ni according to a fixed proportion_1-xCo_x(x is more than or equal to 0 and less than or equal to 1), wherein the total metal molar concentration of the solution is controlled to be 0.01-2 mol/L;

s2, carrying out wet coprecipitation after uniform mixing, controlling the pH value of the reaction by adding liquid alkali under the protection of nitrogen to realize the regulation and control of the granularity of the precursor, wherein the pH control range is 6.5-13.0, and meanwhile, the regulation and control of the width of D502-20 microns is realized by grading;

s3, after synthesizing the nickel-cobalt binary precursor, removing corresponding impurities through filter pressing or centrifugal water washing, and then drying, sieving and removing iron;

the second step is that: preparation of nickel-cobalt-manganese ternary precursor

According to composition Ni_1-x-yCo_xMn_y（OzH）₂(wherein x is more than or equal to 0 and less than or equal to 1, y is more than or equal to 0 and less than or equal to 1, and z is more than or equal to 0 and less than or equal to 2) by the following steps:

s1, slurrying the nickel-cobalt binary precursor synthesized in the first step for later use;

s2, dissolving a manganese source for later use, wherein the content concentration of the manganese source is controlled to be 0.01-2 mol/L;

s3, after slurrying the nickel-cobalt binary precursor, carrying out composite synthesis on manganese and the nickel-cobalt binary precursor, introducing air or oxygen for carrying out oxidation precipitation reaction, adjusting the air or oxygen according to the manganese source feeding speed, controlling the PH value to realize regulation and control of the granularity of the precursor, wherein the PH control range is 6.5-13, and meanwhile, realizing regulation and control of the width of D502.5-20 microns by classification;

s4, after synthesizing the nickel-cobalt-manganese ternary precursor, removing corresponding impurities through filter pressing or centrifugal water washing, and then drying, sieving and removing iron;

the third step: post-treatment Process

And (4) crushing or dispersing, sieving and removing iron of the sintered finished product, and finally packaging to obtain the finished product.

2. The method for preparing the ternary precursor for nickel-cobalt-manganese step-by-step synthesis according to claim 1, wherein the method comprises the following steps: the nickel source is mainly one or more of metal nickel, nickel sulfate and nickel chloride, the cobalt source is mainly one or more of metal cobalt, cobalt sulfate and cobalt chloride, and the manganese source is mainly one or more of manganese sulfate and manganese chloride.

3. The method for preparing the ternary precursor for nickel-cobalt-manganese step-by-step synthesis according to claim 1, wherein the method comprises the following steps: in the wet coprecipitation process, the reaction temperature is controlled to be 40-80 ℃, the synthesis mode is a continuous mode or a batch mode, the liquid inlet flow rate of the molten metal is controlled to be more than 2L/min, and the ratio of ammonia to metal elements is controlled to be more than 0.05.

4. The method for preparing the ternary precursor for nickel-cobalt-manganese step-by-step synthesis according to claim 1, wherein the method comprises the following steps: in the process of compositely synthesizing the manganese and nickel-cobalt binary precursor, the reaction temperature is controlled to be 40-80 ℃, the manganese source feeding speed is controlled to be more than 1L/min, and the ratio of the metal elements of ammonia and manganese is controlled to be more than 0.01.