CN110182857B - High-activity petal-shaped nickel-cobalt-manganese ternary precursor and preparation method thereof - Google Patents

Abstract

A highly active petal-shaped nickel-cobalt-manganese ternary precursor and a preparation method thereof, wherein the chemical formula of the nickel-cobalt-manganese ternary precursor is: Ni _a Co _b Mn _c (OH)2, wherein a+b+c= 1, and 0.33≤a≤0.9, 0.05≤b≤0.33, 0.05≤c≤0.33, the specific surface area of the nickel-cobalt-manganese ternary precursor is 20-30m ² /g, and it is petal-shaped; the present invention also includes The preparation method of the highly active petal-shaped nickel-cobalt-manganese ternary precursor. The highly active petal-shaped ternary precursor of the invention is petal-shaped, has a large specific surface area, and has high activity; the process operation is simple and the requirement for production equipment is not high.

Description

A kind of highly active petaloid nickel-cobalt-manganese ternary precursor and preparation method thereof

technical field

The invention relates to the technical field of manufacturing a nickel-cobalt-manganese ternary precursor, in particular to a highly active petal-shaped nickel-cobalt-manganese ternary precursor and a preparation method thereof.

Background technique

Lithium-ion batteries were first commercialized in Japan, and their uses have also expanded from the 3C field to energy storage, power and other fields. Due to the continuous improvement of people's requirements for power battery energy density, safety performance, cost of use, and cycle performance. The cathode material is one of the key materials in the manufacture of lithium-ion batteries, which determines the energy density, safety performance, cost of use, and cycle performance of the cell.

At present, the lithium-ion battery cathode materials that have been successfully industrialized include layered ternary cathode materials, spinel lithium manganate cathode materials, and olivine lithium iron phosphate cathode materials. Due to the defects of lithium iron phosphate and lithium manganate in energy density, ternary cathode materials have become the mainstream in the market.

The industrial synthesis of ternary materials is mainly by high-temperature solid-phase method: the ternary precursor is mixed with lithium carbonate or lithium hydroxide and sintered evenly. The ternary precursor determines the performance of the ternary cathode material to a certain extent. Therefore, it is necessary to To prepare a ternary material with excellent performance, a ternary precursor with excellent performance index must be prepared first; at present, the preparation process of hydroxide co-precipitation is generally used in industrialization. This preparation process is complicated and requires high production equipment. The ternary precursor is not uniformly doped, has a small specific surface area, and has low activity.

SUMMARY OF THE INVENTION

The technical problem to be solved by the present invention is to overcome the above-mentioned defects in the prior art, and to provide a highly active petal-shaped nickel-cobalt-manganese ternary precursor and a preparation method thereof. Large specific surface area, high activity; the preparation process is simple and easy to operate, and the requirements for production equipment are not high.

The technical solution adopted by the present invention to solve the technical problem is: a highly active petal-shaped nickel-cobalt-manganese ternary precursor, and its general chemical formula is: Ni _a Co _b Mn _c (OH) , wherein a+b+c =1, and 0.33≤a≤0.9, 0.05≤b≤0.33, 0.05≤c≤0.33, the specific surface area of the nickel-cobalt-manganese ternary precursor is 20-30 m ² /g, and the particle shape is petal-like.

The preparation method of the highly active petal-shaped nickel-cobalt-manganese ternary precursor of the present invention includes the following steps: (1) preparing a nickel-cobalt-manganese soluble salt solution, an ammonia solution, an alkali solution and a reaction bottom solution; (2) adding the Add the metal salt aqueous solution to the nickel-cobalt-manganese soluble salt solution to obtain the doping aqueous solution; (3) add the reaction bottom liquid to the reaction kettle, turn on stirring, and pass in an inert gas, and then use a precision metering pump to feed the doping solution (4) Continue stirring, when the liquid level in the reaction kettle rises to be close to the lid of the reaction kettle, open the overflow valve, and make the reaction liquid flow into the aging kettle for aging (5) solid-liquid separation is carried out on the aged product, the obtained solid material is washed, then dried and sieved to obtain a petal-shaped nickel-cobalt-manganese ternary precursor doped with metal elements.

Further, in step (1), the concentration of the nickel-cobalt-manganese soluble salt solution is 1.0-3.5mol/L, the concentration of the ammonia solution is 8-12mol/L, and the concentration of the alkali solution is 5- 13mol/L, the reaction bottom liquid is prepared from ammonia water, soluble ammonium salt and alkali liquor.

Further, in step (1), the nickel-cobalt-manganese soluble salt aqueous solution is an aqueous solution of nickel salt, cobalt salt, and manganese salt, wherein the molar ratio of nickel: cobalt: manganese is 1:1:1 to 9:0.5: 0.5.

Further, in step (1), the reaction bottom liquid is prepared from soluble ammonium salt aqueous solution, ammonia water and alkali liquor, the ammonia concentration of the reaction bottom liquid is 0.4mol/L, and the pH value is in the range of 11.2-11.5, The ratio of ammonia water to soluble ammonium salt is 3:1.

The method for preparing the bottom liquid of the reaction kettle: first prepare a soluble ammonium salt aqueous solution, then add 12 mol/L ammonia water in proportion to the prepared soluble ammonium salt, and finally add an appropriate amount of water and alkali solution to make the ammonia concentration in the bottom liquid 0.4 mol /L, the pH value is in the range of 11.2-11.5, and the ratio of ammonia water to soluble ammonium salt is 3:1. )

Further, in step (1), the soluble ammonium salt is two or more of ammonium sulfate, ammonium carbonate, ammonium chloride, ammonium tartrate, ammonium oxalate, and ammonium citrate, and the lye is sodium hydroxide aqueous solution.

Further, in step (2), the metal salt aqueous solution is one or more sulfate aqueous solutions of aluminum, magnesium, zirconium, titanium, yttrium, tungsten, molybdenum, calcium, niobium, lanthanum, indium, strontium, and tantalum .

Further, in step (3), the addition amount of the reaction bottom liquid is 1/4~3/4 of the volume of the reaction kettle, and the consumption of the metal salt aqueous solution does not exceed 1/1 of the total amount of the nickel-cobalt-manganese soluble salt solution. %.

Further, in step (3), the stirring speed is 300-700r/min, the reaction temperature is 50-65°C, the ammonia concentration is maintained at 0.4-1.0mol/L, and the pH value is 10.5-12.5.

Further, in step (4), the reaction solution that overflowed in the first 20 hours was discharged as unqualified products, and the stirring speed of the aging kettle was adjusted to 150 rpm, and the aging time was maintained for 8h-10h.

Further, in step (5), the aging product is filtered with a filter, firstly washed with alkaline solution, and then continuously washed with deionized water until the pH value of the final washing water is 7-8, and the washing is completed. ; The washed precipitate is dried at a temperature of 150±10°C.

The beneficial effects of the present invention are: 1) the nickel-cobalt-manganese ternary precursor of the present invention has a large specific surface area and high activity, and can be used to prepare a large single-crystal ternary positive electrode material; 2) the preparation method is easy to operate and requires no production equipment. The primary particle arrangement of the precursor can be selectively regulated by selectively adjusting parameters such as the amount of the reaction bottom liquid, the composition of the reaction bottom liquid, the addition amount of the reactants, the addition speed, and the stirring intensity of the reaction kettle during the co-precipitation reaction; 3) Through liquid-phase doping, the uniform precipitation of doping elements can be achieved, the stability and conductivity of the lattice of the ternary material prepared in the later stage can be improved, the cycle performance of the cathode material can be improved, and the uneven dry doping can be avoided, resulting in electrical properties. Bad things happen.

Description of drawings

Fig. 1 is the topography of the nickel-cobalt-manganese ternary precursor of the embodiment of the present invention 1 under 5000 times electron microscope;

Fig. 2 is the topography of the nickel-cobalt-manganese ternary precursor of Example 1 of the present invention under a 10,000-fold electron microscope;

Fig. 3 is the electron microscope topography of the nickel-cobalt-manganese ternary positive electrode material obtained with the nickel-cobalt-manganese ternary precursor of Example 1 of the present invention;

FIG. 4 is a diagram showing the electrical properties of the nickel-cobalt-manganese ternary positive electrode material obtained by using the nickel-cobalt-manganese ternary precursor in Example 1 of the present invention.

Detailed ways

Below in conjunction with embodiment, the specific embodiment of the present invention is described in further detail:

Embodiment 1 of the present invention is a highly active petal-shaped nickel-cobalt-manganese ternary precursor, and its general chemical formula is: Ni _a Co _b Mn _c (OH) 2, wherein a+b+c=1, and 0.33≤a≤0.9, 0.05≤b≤0.33, 0.05≤c≤0.33, the specific surface area of the ternary precursor is 20-30 m ² /g; its particle morphology is shown in Figures 1 and 2, and the particle shape is petal-shaped.

Embodiment 1 of the preparation method of the highly active petaloid ternary precursor of the present invention comprises the following steps:

(1) Prepare 2 mol/L nickel-cobalt-manganese soluble salt solution in molar ratio of Ni:Co:Mn=6:2:2, prepare 11mol/L sodium hydroxide solution, prepare 12mol/L ammonia solution, mix hydrogen Sodium oxide, ammonia water and ammonium sulfate are prepared into a reaction bottom liquid with a pH value of 11.2 and an ammonia concentration of 0.4 mol/L, wherein the consumption of ammonia water and ammonium sulfate in the bottom liquid is 3:1;

(2) adding a metal salt aqueous solution to the nickel-cobalt-manganese soluble salt solution to obtain a doping aqueous solution, and the metal salt aqueous solution is a mixed solution of zirconium sulfate and titanium sulfate with a concentration of 0.8 g/L;

(3) Add the reaction bottom liquid that is 1/4 of the volume of the reaction kettle in the reaction kettle, then start stirring, the stirring speed is 700rpm, the temperature is kept at 55 ° C, and then the inert gas is introduced, and then the precision metering pump is used to enter the The doping aqueous solution, the aqueous ammonia solution and the alkali solution are described, and the reaction is carried out, and the temperature of the reaction kettle system is kept at 54 ± 2 ° C, the pH value is 11.1 ± 0.1, and the ammonia concentration is 0.5 ± 0.1 mol/L during the reaction;

(4) Continue stirring. When the liquid level in the reaction kettle rises to near the lid of the reaction kettle, open the overflow valve to make the reaction liquid flow into the aging kettle for aging. During the aging process, the stirring speed is adjusted to 150rpm to keep the aging process. time 8h;

(5) Carry out solid-liquid separation on the aged product, wash the obtained solid material, then dry and sieve to obtain petal-shaped nickel-cobalt-manganese doped with zirconium and titanium with a specific surface area of 20-25 m ² /g The ternary precursor, the morphology is shown in Figure 1 and Figure 2.

Weigh 5g of the nickel-cobalt-manganese ternary precursor and 2.3g of lithium hydroxide monohydrate, put them into a ball mill for mixing, and mill them in a ball mill for 20 hours to fully mix them evenly. ; Then in a tube furnace, heat treatment at 450 °C for 3 hours, then heat treatment at 700 °C for 5 hours, and finally heat treatment at 900-930 °C for 12 hours, maintaining an oxygen atmosphere throughout the whole process, the obtained products are dissociated and sieved, and finally zirconium and titanium are obtained. The morphology of the co-doped ternary cathode material is shown in Figure 3, and the measured electrical properties are shown in Figure 4: In the voltage range of 3.0-4.3V, the obtained ternary cathode material has a 1C discharge capacity as high as 163.2mAh/g, and after 50 cycles, the capacity retention rate is as high as 97.3%.

Embodiment 2 of the preparation method of the highly active petaloid nickel-cobalt-manganese ternary precursor of the present invention comprises the following steps:

(1) Prepare 2 mol/L nickel-cobalt-manganese soluble salt solution in molar ratio Ni: Co: Mn=65:15:20, prepare 11 mol/L sodium hydroxide solution, prepare 12 mol/L ammonia solution, mix hydrogen Sodium oxide, ammonia water and ammonium sulfate are prepared into a reaction bottom liquid with a pH value of 11.2 and an ammonia concentration of 0.4 mol/L, wherein the consumption of ammonia water and ammonium sulfate in the bottom liquid is 3:1;

(2) adding a metal salt aqueous solution to the nickel-cobalt-manganese soluble salt aqueous solution to obtain a doping aqueous solution, and the metal salt aqueous solution is a mixed solution of zirconium sulfate and aluminum sulfate with a concentration of 0.8 g/L;

(3) Add the reaction bottom liquid which is 1/2 of the volume of the reaction kettle in the reaction kettle, then start stirring, the stirring speed is 600rpm, the temperature is kept at 60°C, and then the inert gas is introduced, and then the precision metering pump is used to enter the The doping aqueous solution, the aqueous ammonia solution and the alkali solution are reacted, and the temperature of the reaction kettle system is kept at 57-63° C., the pH value is 11.1-11.5, and the ammonia concentration is 0.4-0.6 mol/L during the reaction;

(4) Continue stirring. When the liquid level in the reaction kettle rises to near the lid of the reaction kettle, open the overflow valve to make the reaction liquid flow into the aging kettle for aging. During the aging process, the stirring speed is adjusted to 150rpm to keep the aging process. time 8h;

(5) Perform solid-liquid separation on the aged material, wash the obtained solid material, then dry and sieve to obtain petal-shaped nickel-cobalt-manganese doped with zirconium and aluminum with a specific surface area of 20-25 m ² /g Ternary precursors.

Weigh 5g of the nickel-cobalt-manganese ternary precursor and 2.3g of lithium hydroxide monohydrate, put them into a ball mill for mixing, and mill them in a ball mill for 20 hours to fully mix them evenly. ; Then in a tube furnace, heat treatment at 450 °C for 3 hours, then heat treatment at 700 °C for 5 hours, and finally heat treatment at 900-930 °C for 12 hours, maintaining an oxygen atmosphere throughout the whole process, the obtained products are dissociated and sieved, and finally zirconium and aluminum are obtained. Co-doped ternary cathode material. The electrical properties were measured as follows: in the voltage range of 3.0-4.3V, the 1C discharge capacity of the obtained ternary cathode material was as high as 168.5mAh/g, and after 50 cycles, the capacity retention rate was as high as 97.25%.

Embodiment 3 of the preparation method of the highly active petal-shaped ternary precursor of the present invention comprises the following steps:

(1) Prepare 2 mol/L nickel-cobalt-manganese soluble salt solution in molar ratio Ni:Co:Mn=83:11:6, prepare 11mol/L sodium hydroxide solution, prepare 12mol/L ammonia solution, mix hydrogen Sodium oxide, ammonia water and ammonium sulfate are prepared into a reaction bottom liquid with a pH value of 11.5 and an ammonia concentration of 0.4 mol/L, wherein the consumption of ammonia water and ammonium sulfate in the bottom liquid is 3:1;

(2) adding a metal salt aqueous solution to the nickel-cobalt-manganese soluble salt solution to obtain a doping aqueous solution, and the metal salt aqueous solution is a mixed solution of zirconium sulfate and titanium sulfate with a concentration of 0.8 g/L;

(3) Add the reaction bottom liquid that is 1/4 of the volume of the reaction kettle in the reaction kettle, then start stirring, the stirring speed is 500rpm, the temperature is maintained at 60 ° C, and then the inert gas is introduced, and then the precision metering pump is used to enter the Describe the doping aqueous solution, ammonia solution and alkali solution, make it react, during the reaction, keep the temperature of the reactor system at 60±2℃, the pH value is 12±0.3, and the ammonia concentration is 0.8±0.1mol/L;

(4) Continue stirring. When the liquid level in the reaction kettle rises to near the lid of the reaction kettle, open the overflow valve to make the reaction liquid flow into the aging kettle for aging. During the aging process, the stirring speed is adjusted to 150rpm to keep the aging process. time 8h;

(5) Perform solid-liquid separation on the aged material, wash the obtained solid material, then dry and sieve to obtain petal-shaped nickel-cobalt-manganese doped with zirconium and titanium with a specific surface area of 20-30 m ² /g Ternary precursors.

Weigh 5g of the nickel-cobalt-manganese ternary precursor and 2.3g of lithium hydroxide monohydrate, put them into a ball mill for mixing, and mill them in a ball mill for 20 hours to fully mix them evenly. ; Then in a tube furnace, heat treatment at 450 °C for 3 hours, then heat treatment at 700 °C for 5 hours, and finally heat treatment at 900-930 °C for 12 hours, maintaining an oxygen atmosphere throughout the whole process, the obtained products are dissociated and sieved, and finally zirconium and titanium are obtained. Co-doped nickel-cobalt-manganese ternary cathode material. The electrical properties were measured as follows: in the voltage range of 3.0-4.3V, the 1C discharge capacity of the obtained ternary cathode material was as high as 178.51mAh/g, and after 50 cycles, the capacity retention rate was as high as 96.56%.

The above are only the preferred embodiments of the present invention. It should be pointed out that for those of ordinary skill in the art, without departing from the technical principles of the present invention, several improvements and modifications can also be made. It should be regarded as being within the protection scope of the present invention.

Claims (8)

1. A preparation method of a high-activity petal-shaped nickel-cobalt-manganese ternary precursor doped with metal elements is characterized by comprising the following steps:

(1) preparing a nickel-cobalt-manganese soluble salt aqueous solution, an ammonia aqueous solution, an alkali liquor and a reaction base solution;

(2) adding a metal salt aqueous solution into the nickel-cobalt-manganese soluble salt aqueous solution to obtain a doped aqueous solution;

(3) adding reaction base liquid into the reaction kettle, starting stirring, introducing inert gas, and then introducing the doped aqueous solution, the ammonia water solution and the alkali liquor by using a precise metering pump to react;

(4) continuously stirring, and opening an overflow valve when the liquid level in the reaction kettle rises to be close to the cover of the reaction kettle, so that the reaction liquid flows into the aging kettle for aging;

(5) carrying out solid-liquid separation on the aged product, washing the obtained solid material, and then drying and sieving to obtain a petal-shaped nickel-cobalt-manganese ternary precursor doped with metal elements;

in the step (1), the reaction bottom liquid is prepared from an ammonia water solution, a soluble ammonium salt and an alkali liquor;

in the step (1), the nickel-cobalt-manganese soluble salt aqueous solution is an aqueous solution of nickel salt, cobalt salt and manganese salt, wherein the molar ratio of nickel to cobalt to manganese is 1:1:1 to 9:0.5: 0.5;

in the step (2), the metal salt aqueous solution is one or more sulfate aqueous solutions of aluminum, magnesium, zirconium, titanium, yttrium, tungsten, molybdenum, calcium, niobium, lanthanum, indium, strontium and tantalum;

in the step (3), the addition amount of the reaction bottom liquid is 1/4-3/4 of the volume of the reaction kettle, and the usage amount of the metal salt aqueous solution is not more than 1% of the total amount of the nickel-cobalt-manganese soluble salt aqueous solution;

in the step (3), the stirring speed is 300-700r/min, the reaction temperature is 50-65 ℃, the ammonia concentration is maintained to be 0.4-1.0 mol/L, and the pH = 10.5-12.5;

the alkali liquor is sodium hydroxide aqueous solution; the specific surface area of the obtained ternary precursor is 20-30m²(ii)/g, and the shape of the particles is petal-shaped.

2. The method for preparing the high-activity petal-shaped metallic element doped nickel-cobalt-manganese ternary precursor as claimed in claim 1, wherein in the step (1), the concentration of the nickel-cobalt-manganese soluble salt aqueous solution is 1.0-3.5 mol/L, the concentration of the ammonia aqueous solution is 8-12 mol/L, and the concentration of the alkali liquor is 5-13 mol/L.

3. The method for preparing the petal-shaped high-activity ternary precursor of nickel, cobalt and manganese doped with metal elements according to claim 1 or 2, wherein the soluble ammonium salt is two or more of ammonium sulfate, ammonium carbonate, ammonium chloride, ammonium tartrate, ammonium oxalate and ammonium citrate.

4. The method for preparing the petal-shaped metallic element doped nickel-cobalt-manganese ternary precursor as claimed in claim 1 or 2, wherein in step (4), the reaction solution overflowing in the first 20h is discharged as a rejected product, the stirring speed of the aging kettle is adjusted to 150rpm, and the aging time is kept for 8h-10 h.

5. The method for preparing the high-activity petal-shaped metallic element doped nickel-cobalt-manganese ternary precursor as claimed in claim 3, wherein in the step (4), the reaction solution overflowing in the first 20h is discharged as a rejected product, the stirring speed of the aging kettle is adjusted to 150rpm, and the aging time is kept for 8h-10 h.

6. The method for preparing the high-activity petal-shaped metallic element doped nickel-cobalt-manganese ternary precursor according to claim 1 or 2, wherein in the step (5), the aged product is filtered by a filter, washed by alkali liquor and then by deionized water until the pH value of the final washing water is 7-8, and the washing is finished; the washed precipitate was dried at a temperature of 150 + -10 deg.C.

7. The method for preparing the high-activity petal-shaped metallic element doped nickel-cobalt-manganese ternary precursor as claimed in claim 3, wherein in the step (5), the aging product is filtered by a filter, washed by alkaline solution and then by deionized water until the final pH value of the washing water is 7-8, and the washing is finished; the washed precipitate was dried at a temperature of 150 + -10 deg.C.

8. The method for preparing the high-activity petal-shaped metallic element doped nickel-cobalt-manganese ternary precursor according to claim 4, wherein in the step (5), the aged product is filtered by a filter, washed by alkaline solution and then by deionized water until the pH value of the final washing water is 7-8, and the washing is finished; the washed precipitate was dried at a temperature of 150 + -10 deg.C.

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