CN112086616A - Preparation method of large (010) crystal face nickel-cobalt-manganese/aluminum layered positive electrode material - Google Patents

Preparation method of large (010) crystal face nickel-cobalt-manganese/aluminum layered positive electrode material Download PDF

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CN112086616A
CN112086616A CN202011141721.6A CN202011141721A CN112086616A CN 112086616 A CN112086616 A CN 112086616A CN 202011141721 A CN202011141721 A CN 202011141721A CN 112086616 A CN112086616 A CN 112086616A
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manganese
cobalt
nickel
aluminum
crystal face
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CN112086616B (en
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刘国标
单丽梅
王泽忠
李海荣
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Sichuan Engineering Technical College
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    • H01M4/049—Manufacturing of an active layer by chemical means
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    • H01M10/052—Li-accumulators
    • H01M10/0525—Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
    • H—ELECTRICITY
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    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
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    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/48—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides
    • H01M4/50—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of manganese
    • H01M4/505—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of manganese of mixed oxides or hydroxides containing manganese for inserting or intercalating light metals, e.g. LiMn2O4 or LiMn2OxFy
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    • H01M4/48—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides
    • H01M4/52—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of nickel, cobalt or iron
    • H01M4/525—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of nickel, cobalt or iron of mixed oxides or hydroxides containing iron, cobalt or nickel for inserting or intercalating light metals, e.g. LiNiO2, LiCoO2 or LiCoOxFy
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    • H01M2004/026—Electrodes composed of, or comprising, active material characterised by the polarity
    • H01M2004/028—Positive electrodes
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Abstract

The invention discloses a preparation method of a nickel-cobalt-manganese/aluminum layered anode material with a large (010) crystal face, which comprises the following steps: 1) preparing crystal nucleus; inorganic salt or organic salt of nickel, cobalt and/or manganese and aluminum is used as a raw material, and a micro-controlled coprecipitation method is adopted to prepare flaky crystal nucleus with good dispersibility; 2) preparing a precursor; taking the crystal nucleus prepared in the step 1) as a substrate to carry out coprecipitation reaction, and controlling the growth of the wafer in the thickness direction to obtain a hydroxide precursor with a large crystal face area (010); 3) preparing a positive electrode material; the prepared precursor is mixed with lithium-containing compound and/or inorganic salt or organic salt of manganese and aluminum, and the mixture is calcined at high temperature to obtain the nickel-cobalt-manganese/aluminum layered cathode material. The particle size of the primary particles of the cathode material prepared by the invention is large, the prepared primary particles are micron-sized particles, the crystal face area of the primary particles (010) is large, the requirement of downstream lithium ion battery production enterprises on high compaction density of the material can be well met, the preparation process is simple, and the process cost is low.

Description

Preparation method of large (010) crystal face nickel-cobalt-manganese/aluminum layered positive electrode material
Technical Field
The invention relates to the technical field of lithium ion battery materials, in particular to a preparation method of a large (010) crystal face nickel-cobalt-manganese/aluminum layered positive electrode material.
Background
Because the nickel-cobalt-manganese/aluminum layered positive electrode material has the advantages of high volume, high mass energy density, moderate price and the like, the nickel-cobalt-manganese/aluminum layered positive electrode material has become the first choice of the positive electrode material for producing high-energy-density batteries in various large battery enterprises, but the lithium ion conductivity of the nickel-cobalt-manganese/aluminum layered positive electrode material is not high, and Li is not high+The embedding/separating of large single particles in the circulating process is long, the electrode polarization is serious, and in practical application, the nickel-cobalt-manganese/aluminum layered positive electrode material cannot be large single particles (D)50Greater than 10 μm) resulting in a compacted density of the already commercialized polycrystalline spherical and small single crystal nickel cobalt manganese/aluminum layered cathode material that is much lower than the large single particle LiCoO with a layered crystal structure2Compacted density of the positive electrode material.
In order to solve the problem that the compact density and the electrochemical performance of the nickel-cobalt-manganese/aluminum layered cathode material are difficult to be simultaneously considered due to low lithium ion conductivity of the nickel-cobalt-manganese/aluminum layered cathode material, a great deal of research is focused on increasing the (010) crystal face (which is Li) of the nickel-cobalt-manganese/aluminum layered cathode material particles+Vertical crystal plane of the insertion/extraction channel) to improve the lithium ion conductivity thereof. However, like other layered cathode materials, (010) crystal planes of the nickel-cobalt-manganese/aluminum layered cathode material are crystal planes with higher surface energy, and in order to maintain the material to have lower surface energy in an equilibrium state, in a high-temperature solid-phase synthesis process or high-temperature heat preservation, the (010) crystal planesThe area tends to decrease, so how to increase the crystal plane area of the nickel-cobalt-manganese/aluminum layered cathode material (010) is one of the hot spots of the current research on the nickel-cobalt-manganese/aluminum layered cathode material.
Up to now, many methods have been reported to be capable of improving the crystal plane area of the nickel-cobalt-manganese/aluminum layered cathode material (010), wherein one method is to directly generate the nickel-cobalt-manganese/aluminum layered cathode material with a larger crystal plane area (010) in a liquid phase, and then strengthen the crystal structure of the nickel-cobalt-manganese/aluminum layered cathode material through subsequent high-temperature calcination, so as to obtain the nickel-cobalt-manganese/aluminum layered cathode material with a larger crystal plane area (010) and excellent electrochemical performance. Although the relative ratio of the (010) crystal face area of the nickel-cobalt-manganese/aluminum layered cathode material prepared by the method to the particle size of the primary particles is relatively large, the particle size of secondary particles formed by the primary particles and the primary particles or the particle size of single particles (dispersed single particles can be prepared by partial methods) is small (generally nano-scale), and the requirements of downstream battery enterprises on high tap density and high tap density of the material cannot be met. The other method is to generate a precursor (oxide, oxalate or hydroxide) in a liquid phase, and mainly obtain the nickel-cobalt-manganese/aluminum layered cathode material with a large (010) crystal face area by controlling a subsequent calcination system. The method can prepare the nickel-cobalt-manganese/aluminum layered cathode material with higher tap density and compaction density, but the method mainly controls a subsequent calcination system to relieve the reduction of the crystal face area of the nickel-cobalt-manganese/aluminum layered cathode material (010), and the crystal face area of (010) is still smaller.
Patent document CN109244454A discloses that a nickel-cobalt-manganese ternary positive electrode material precursor is used as a primer (also called a seed crystal or a nucleating agent) to regulate the crystal face exposure degree of the precursor (010) so as to regulate the crystal face exposure degree of the positive electrode material (010). Patent document CN109742337A uses a nanometer level aggregation wafer as a seed crystal to regulate the thickness of the precursor wafer to regulate the crystal plane area of the positive electrode material (010). The primary particles of the anode material prepared by the two methods are all in a nanometer level, so that the area of a (010) crystal face is still small. How to prepare the nickel-cobalt-manganese/aluminum layered cathode material with large (010) crystal face area, which can be put into practical application, is still a difficulty in industrial production.
Disclosure of Invention
The invention provides a preparation method of a nickel-cobalt-manganese/aluminum layered cathode material with a large (010) crystal face, aiming at the problems that the crystal face area of a nickel-cobalt-manganese/aluminum layered cathode material (010) prepared by the existing preparation method is small, the particle size of primary particles is small, and the high tap density of the material which can not meet the requirements of downstream battery enterprises can be achieved.
In order to solve the technical problems, the technical scheme adopted by the invention is as follows:
a preparation method of a large (010) crystal face nickel-cobalt-manganese/aluminum layered cathode material comprises the following steps:
1) preparing crystal nucleus; inorganic salt or organic salt of nickel, cobalt and/or manganese and aluminum is used as a raw material, and a micro-controlled coprecipitation method is adopted to prepare flaky crystal nuclei with good dispersibility, wherein more than 90% of crystal nuclei in the crystal nuclei have the size not less than 2 mu m, and the spacing between more than 90% of the crystal nuclei is not less than 2 mu m;
2) preparing a precursor; performing coprecipitation reaction by using the crystal nucleus prepared in the step 1) as a substrate, and controlling the growth of a wafer in the thickness direction to obtain a hydroxide precursor with a large crystal face area of (010), wherein the size of more than 90% of primary particles in the precursor with the size of not less than 3 mu m is not less than 3 mu m, and the size of the length and the width of the crystal face of more than 90% of the primary particles (010) is not less than 2 mu m;
3) preparing a positive electrode material; mixing the precursor prepared in the step 2) with a lithium-containing compound and/or inorganic salt or organic salt of manganese and aluminum, and calcining at high temperature to obtain the nickel-cobalt-manganese/aluminum layered cathode material.
In the crystal nucleus prepared by adopting the micro-control coprecipitation method in the step 1), the size of the wafer is larger, the space between the wafers is larger, the growth of the wafer is convenient in the preparation process of the precursor, and the area of the crystal face (010) is increased.
In the above technical solution, further, more than 90% of crystal face area of primary particles (010) in the precursor is not less than 6 μm2。
In the above technical solution, further, the operation process of the micro-controlled co-precipitation method in step 1) is as follows:
under the atmosphere of inert gas, dropwise adding inorganic salt or organic salt solution of nickel, cobalt and/or manganese and aluminum, a precipitator and a complexing agent into a reaction kettle containing bottom water at a certain speed respectively, controlling the pH value in the reaction kettle to be 8.0-10.0, preferably 10.0, controlling the ammonia concentration in the reaction kettle to be 2.0-7.0mol/L, preferably 3.0-4.0mol/L, controlling the dropwise adding speed of the inorganic salt or organic salt solution of nickel, cobalt and/or manganese and aluminum to be 0.05-1.0 ml/min, preferably 0.3-0.5 ml/min, and reacting at the temperature of 40-60 ℃ for 1-5 hours to obtain crystal nuclei.
In the above technical solution, further, the coprecipitation reaction operation process in step 2) is as follows:
dropwise adding inorganic salt or organic salt solution of nickel, cobalt and/or manganese and aluminum, a precipitator and a complexing agent into a reaction kettle, controlling the dropwise adding speed of the inorganic salt or organic salt solution of nickel, cobalt and/or manganese and aluminum and the precipitator to be 3.0-5.0ml/min, controlling the pH value in the reaction kettle to be 10.5-12.0, preferably 11.2, controlling the ammonia concentration in the reaction kettle to be 0.1-1.0mol/L, preferably 0.3-0.4mol/L, reacting for 30-60 hours at the temperature of 40-60 ℃ to obtain hydroxide slurry, and washing and drying the hydroxide slurry to obtain a precursor.
In the above technical solution, further, the molar concentration of the inorganic salt or organic salt solution of nickel, cobalt and/or manganese, aluminum is 1.0-3.0mol/L, the molar concentration of the precipitant is 2.0-6.0mol/L, and the molar concentration of the complexing agent is 5.0-15.0 mol/L.
In the above technical scheme, further, the precipitant is a NaOH solution, the complexing agent is an ammonia water solution, and the bottom water is a solution containing ammonia water.
In the above technical solution, further, the inorganic salt or organic salt solution of manganese and aluminum is added in step 1) or step 3).
In the above technical solution, further, the size of more than 90% of primary particles in the layered positive electrode material is not less than 3 μm, and the length and width of crystal faces of more than 90% of primary particles (010) are not less than 2 μm; preferably more than 90% of the crystal face area of the primary particles (010) is not less than 6 mu m2。
In the above technical solution, further, the calcining in step 3) by using a sectional calcining process includes:
the first stage calcination temperature is 400-;
the second-stage calcination temperature is 700-;
it is preferable that a certain amount of oxygen is added during the calcination when the molar percentage of nickel atoms in the positive electrode material is not less than 60%.
In the above technical solution, further, the inorganic salt or organic salt of nickel, cobalt and/or manganese, aluminum is sulfate, nitrate, chloride or acetate; the lithium-containing compound is one or more of lithium hydroxide, lithium carbonate, lithium acetate and lithium nitrate.
In the method, nickel, cobalt and manganese ions can generate a complex with ammonia water to reduce the concentration of the nickel, cobalt and manganese ions participating in the reaction solution, thereby slowing down the nucleation speed; meanwhile, the decomposition speed of the complex can be slowed down by reducing the pH value in the reaction solution, and the concentration of nickel, cobalt and manganese ions participating in the reaction solution is reduced, so that the nucleation speed is further slowed down. That is to say, in the crystal nucleus preparation stage, the ammonia water concentration in the reaction solution is increased and the pH value is reduced to slow down the hydroxide nucleation speed, so that the flaky crystal nucleus which is favorable for growing a large (010) crystal face precursor and has good dispersibility is prepared; the crystal nucleus can be further grown into a precursor with micron-sized primary particles and large (010) crystal faces.
The invention has the following beneficial effects:
1) the primary particles of the cathode material prepared by the method are micron-sized particles, and the requirements of downstream lithium battery enterprises on high compaction density and high tap density of the material can be well met.
2) The primary particles (010) of the anode material prepared by the invention have large crystal face area and excellent electrochemical performance, and are particularly suitable for preparing a lithium ion battery with high energy density.
3) The method does not need to adopt a produced precursor as a bottom material or adopt a surfactant as a crystal face optimizing agent, and has simple preparation process and low process cost of the anode material.
Drawings
FIG. 1 is a process flow chart of the preparation method of the large (010) crystal face nickel cobalt manganese/aluminum layered anode material.
FIG. 2a is a schematic view of a crystal nucleus structure prepared in the preparation method of the present invention; FIG. 2b is a schematic structural diagram of a precursor prepared by the preparation method of the present invention; fig. 2c is a schematic structural diagram of the nickel-cobalt-manganese/aluminum layered positive electrode material prepared by the preparation method of the present invention.
FIG. 3a is a SEM photograph of a crystal nucleus prepared in example 1 of the present invention; FIG. 3b is a SEM photograph of the precursor prepared in example 1; fig. 3c is an SEM image of the nickel-cobalt-manganese/aluminum layered cathode material prepared in example 1 of the present invention.
Fig. 4 is an XRD spectrum of the nickel-cobalt-manganese/aluminum layered cathode material prepared in example 1 of the present invention.
Fig. 5 is an electrical property test chart of the nickel-cobalt-manganese/aluminum layered cathode material prepared in example 1 of the present invention, where fig. 5a is a first charge-discharge curve, fig. 5b is a rate performance test chart, and fig. 5c is a cycle performance test chart.
FIG. 6a is a SEM photograph of a crystal nucleus prepared in comparative example 1; FIG. 6b is an SEM image of a precursor prepared in a comparative example; fig. 6c is an SEM image of the nickel-cobalt-manganese/aluminum layered cathode material prepared in the comparative example.
Detailed Description
The present invention will be described in further detail with reference to specific examples and comparative examples, but it should not be construed that the scope of the above-described subject matter of the present invention is limited to the following examples, and that all the technologies realized based on the contents of the present invention fall within the scope of the present invention.
Example 1
1) 2.0mol/L of MSO is added under nitrogen atmosphere4(M ═ Ni and Co, wherein the molar ratio of Ni to Co is 0.8: 0.15), 4.0mol/L NaOH solution and 12.0mol/L ammonia water were added dropwise at a rate of about 0.5ml/min to a reaction vessel containing an ammonia water solution having a concentration of 4.0mol/L as bottom water, the pH in the reaction vessel was controlled to 10.0, and ammonia was added dropwiseThe concentration is 3.0-4.0mol/L, the coprecipitation reaction temperature is controlled to be 50 ℃, the materials are continuously added, and the reaction is carried out for 2 hours to obtain Ni0.84Co0.16(OH)2The crystal nuclei, as shown in FIG. 3a, are secondary particles having a particle size of about 8 μm consisting of a small number of well-dispersed wafers having a size larger than 2 μm.
2) Mixing MSO4Adjusting the feeding speed of the solution and NaOH solution to 5.0ml/min, reducing the feeding speed of the ammonia water solution to 0.3ml/min, controlling the pH value in the reaction kettle to be 11.2, controlling the ammonia concentration to be 0.3-0.4mol/L, controlling the coprecipitation reaction temperature to be 50 ℃, and obtaining Ni with large micron-sized particles and (010) large crystal face area after reacting for 50 hours0.84Co0.16(OH)2Slurry, washing and drying the slurry to obtain Ni with micron-sized large primary particles and large (010) crystal face area0.84Co0.16(OH)2Precursor, as shown in fig. 3b, is a secondary particle with a particle size of about 12 μm, consisting of primary particles with a particle size of more than 3 μm.
3) Mixing the dried precursor with LiOH & H2O and aluminum nitrate are uniformly mixed, then the mixture is placed in a tube furnace, the temperature is raised to 500 ℃ at the speed of 5 ℃/min, the heat is preserved for 10 hours, the temperature is raised to 780 ℃ at the speed of 3 ℃/min, the heat is preserved for 15 hours, and LiNi with large micron-sized particles and large (010) crystal face area is obtained0.8Co0.15Al0.05O2The positive electrode material, as shown in fig. 3c, is composed of secondary particles having a particle size of about 12 μm, which are composed of primary particles having a particle size of more than 3 μm, and, as shown in fig. 4, is superior in crystallinity of the positive electrode material crystal.
After the prepared positive electrode material is washed with water and coated and modified, a pole piece is prepared, and the compaction density of the pole piece is as high as 3.83g/cm3Assembling a CR2032 button cell, and testing the electrochemical performance, wherein the electrochemical performance is as follows:
as shown in FIGS. 5a, 5b and 5C, the first coulombic efficiency is 89%, the 0.1C circulation capacity is 206mAh/g, the volume energy density is 2919Wh/L, the capacity retention rate is 95.4% after 100 times of circulation, and the 10C circulation capacity is 96 mAh/g.
Example 2
1) 2.0mol/L of MSO is added under nitrogen atmosphere4(M is Ni, Co and Mn, wherein the molar ratio of Ni to Co to Mn is 0.8 to 0.1) solution, 4.0mol/L NaOH solution and 9.0mol/L ammonia water are respectively added into a reaction kettle which takes 3.0mol/L ammonia water solution as bottom water at the speed of 0.3ml/min dropwise, the pH value in the reaction kettle is controlled to be 10.0, the ammonia concentration is 3.0 to 4.0mol/L, the coprecipitation reaction temperature is controlled to be 50 ℃, the materials are continuously added, and the reaction is carried out for 3 hours to obtain Ni0.8Co0.1Mn0.1(OH)2Crystal nuclei, which are secondary particles having a particle size of about 9 μm consisting of a small number of well-dispersed wafers having a particle size of more than 2 μm.
2) Mixing MSO4The feeding speed of the solution and NaOH solution is adjusted to be 5.0ml/min, the feeding speed of the ammonia water solution is kept to be 0.3ml/min, the pH value is controlled to be 11.0, the ammonia concentration is 0.3-0.4mol/L, the coprecipitation reaction temperature is controlled to be 50 ℃, and after 50 hours of reaction, Ni with large micron-sized particles and large (010) crystal face area is obtained0.8Co0.1Mn0.1(OH)2Slurry, washing and drying the slurry to obtain Ni with micron-sized large primary particles and large (010) crystal face area0.8Co0.1Mn0.1(OH)2A precursor which is a secondary particle with the particle size of about 12.5 μm and consists of a primary particle with the particle size of more than 3 μm.
3) Mixing the dried precursor with LiOH & H2O is uniformly mixed, then the mixture is placed in a tube furnace, the temperature is raised to 500 ℃ at the rate of 3 ℃/min and then is preserved for 10 hours, the temperature is raised to 790 ℃ at the rate of 3 ℃/min and then is preserved for 18 hours, and LiNi with large micron-sized particles and large (010) crystal face area is obtained0.8Co0.1Mn0.1O2A positive electrode material which is a secondary particle having a particle diameter of about 12.5 μm composed of a primary particle having a particle diameter of more than 3 μm.
After the prepared positive electrode material is washed with water and coated and modified, a pole piece is prepared, and the compaction density of the pole piece is as high as 3.81g/cm3Assembling a CR2032 button cell, and testing the electrochemical performance, wherein the electrochemical performance is as follows:
the first coulombic efficiency is 89.7%, the 0.1C circulation capacity is up to 207mAh/g, the volume energy density is up to 2918Wh/L, after 100 times of circulation, the capacity retention rate is up to 94.6%, and the 10C circulation capacity is up to 95 mAh/g.
Example 3
1) 2.0mol/L of MSO is added under nitrogen atmosphere4(M is Ni, Co and Mn, wherein the molar ratio of Ni to Co to Mn is 0.9 to 0.05) solution, 4.0mol/L NaOH solution and 12.0mol/L ammonia water are respectively added dropwise into a reaction kettle which takes 4.0mol/L ammonia water solution as bottom water at the speed of 0.3ml/min, the pH value in the reaction kettle is controlled to be 10.0, the ammonia concentration is 3.0 to 4.0mol/L, the coprecipitation reaction temperature is controlled to be 50 ℃, the materials are continuously added, and the reaction is carried out for 5 hours, so that the flaky Ni with good dispersibility is obtained0.9Co0.05Mn0.05(OH)2Crystal nuclei, which are secondary particles having a particle size of about 10 μm composed of a small number of well-dispersed wafers having a particle size of more than 2 μm.
2) Mixing MSO4The feeding speed of the solution and NaOH solution is adjusted to be 5.0ml/min, the feeding speed of the ammonia water solution is adjusted to be 0.4ml/min, the pH value is controlled to be 11.0, the ammonia concentration is 0.3-0.4mol/L, the coprecipitation reaction temperature is controlled to be 50 ℃, and after 50 hours of reaction, Ni with large micron-sized particles and large (010) crystal face area is obtained0.9Co0.05Mn0.05(OH)2Slurry, washing and drying the slurry to obtain Ni with micron-sized large primary particles and large (010) crystal face area0.9Co0.05Mn0.05(OH)2A precursor which is a secondary particle with a particle size of about 13 μm and consists of a primary particle with a particle size of more than 3 μm.
3) Mixing the dried precursor with LiOH & H2O is uniformly mixed, then the mixture is placed in a tube furnace, the temperature is raised to 500 ℃ at the rate of 3 ℃/min and then is preserved for 15 hours, the temperature is raised to 770 ℃ at the rate of 3 ℃/min and then is preserved for 12 hours, and LiNi with large micron-sized particles and large (010) crystal face area is obtained0.9Co0.05Mn0.05O2A positive electrode material which is a secondary particle having a particle diameter of about 13 μm and composed of primary particles having a particle diameter of more than 3 μm.
In the above-mentioned mannerThe prepared anode material is subjected to water washing and coating modification to prepare a pole piece, and the compaction density of the pole piece is as high as 3.85g/cm3Assembling a CR2032 button cell, and testing the electrochemical performance, wherein the electrochemical performance is as follows:
the first coulombic efficiency is 86.7%, the 0.1C circulation capacity is up to 215mAh/g, the volume energy density is up to 3062Wh/L, after 100 times of circulation, the capacity retention rate is up to 91.6%, and the 10C circulation capacity is up to 99 mAh/g.
Example 4
1) 2.0mol/L of MSO is added under nitrogen atmosphere4(M is Ni, Co and Mn, wherein the molar ratio of Ni to Co to Mn is 0.6 to 0.2) solution, 4.0mol/L NaOH solution and 6.0mol/L ammonia water are respectively added into a reaction kettle which takes 2.0mol/L ammonia water solution as bottom water at the speed of 0.5ml/min dropwise, the pH value in the reaction kettle is controlled to be 10.0, the ammonia concentration is 3.0 to 4.0mol/L, the coprecipitation reaction temperature is controlled to be 50 ℃, the materials are continuously added, and the reaction is carried out for 3 hours, so that the flaky Ni with good dispersibility is obtained0.6Co0.6Mn0.6(OH)2Crystal nuclei, which are secondary particles having a particle size of about 9 μm composed of a small number of well-dispersed wafers having a particle size of more than 2 μm.
2) Mixing MSO4Adjusting the feeding speed of the solution and NaOH solution to 5.0ml/min, keeping the feeding speed of the ammonia water solution to 0.5ml/min, controlling the pH value to be 11.2, controlling the ammonia concentration to be 0.3-0.4mol/L, controlling the coprecipitation reaction temperature to be 50 ℃, and obtaining Ni with large micron-sized primary particles and large (010) crystal face area after reacting for 45 hours0.6Co0.2Mn0.2(OH)2Slurry, washing and drying the slurry to obtain Ni with micron-sized large primary particles and large (010) crystal face area0.6Co0.2Mn0.2(OH)2A precursor which is a secondary particle with a particle size of about 13.5 μm and consists of a primary particle with a particle size of more than 3 μm.
3) Mixing the dried precursor with Li2CO3Mixing, placing in a tube furnace, heating to 500 deg.C at 5 deg.C/min, maintaining for 10 hr, heating to 850 deg.C at 3 deg.C/min, maintaining for 15 hr to obtain large micrometer-sized particles (010)LiNi with large crystal face area0.6Co0.2Mn0.2O2A positive electrode material which is a secondary particle having a particle diameter of about 13.5 μm composed of a primary particle having a particle diameter of more than 3 μm.
The positive electrode material prepared by the method is used for preparing a pole piece, and the compaction density of the pole piece is as high as 3.84g/cm3Assembling a CR2032 button cell, and testing the electrochemical performance, wherein the electrochemical performance is as follows:
the first coulombic efficiency is 88.3%, the 0.1C circulation capacity is up to 175mAh/g, the volume energy density is up to 2486Wh/L, after 100 times of circulation, the capacity retention rate is up to 96.3%, and the 10C circulation capacity is up to 90 mAh/g.
Comparative example 1
1) 2.0mol/L of MSO is added under nitrogen atmosphere4(M ═ Ni and Co, wherein the molar ratio of Ni to Co is 0.8: 0.15) solution and 4.0mol/L NaOH solution are respectively added into a reaction kettle containing 0.4mol/L ammonia water solution at the speed of 3.0ml/min, meanwhile, 12.0mol/L ammonia water is added into the reaction kettle containing 0.4mol/L ammonia water solution at the speed of 0.35ml/min, the pH value in the reaction kettle is controlled to be 11.2, the ammonia concentration is 0.3-0.4mol/L, the coprecipitation reaction temperature is controlled to be 50 ℃, the material addition reaction is continued for 2 hours, and Ni is obtained0.84Co0.16(OH)2The crystal nuclei, as shown in FIG. 6a, are secondary particles having a particle size of about 3 μm consisting of a large number of wafers having a particle size of 0.2 to 0.3. mu.m.
2) Mixing MSO4The feeding speed of the solution and NaOH solution is adjusted to be 5ml/min, the feeding speed of the ammonia water solution is reduced to be 0.3ml/min, the pH value is controlled to be 11.2, the ammonia concentration is 0.3-0.4mol/L, the coprecipitation reaction temperature is controlled to be 50 ℃, and after 50 hours of reaction, Ni with primary particles of micron-sized large particles and large (010) crystal face area is obtained0.84Co0.16(OH)2Slurry, washing and drying the slurry to obtain Ni with micron-sized large primary particles and large (010) crystal face area0.84Co0.16(OH)2A precursor, which is a secondary particle having a particle size of about 11.5 μm consisting of primary particles having a particle size of 0.5 to 1.0 μm, as shown in fig. 6 b.
3) Will be driedThe latter precursor reacts with LiOH. H2O and aluminum nitrate are evenly mixed, then the mixture is placed in a tube furnace, the temperature is raised to 500 ℃ at the speed of 5 ℃/min, the heat preservation is carried out for 10 hours, the temperature is raised to 780 ℃ at the speed of 3 ℃/min, the heat preservation is carried out for 15 hours, and the conventional spheroidal LiNi is obtained0.8Co0.15Al0.05O2The positive electrode material, as shown in FIG. 6c, is composed of secondary particles having a particle size of about 11.5 μm, which are composed of primary particles having a particle size of 0.5 to 1.0. mu.m.
After the prepared positive electrode material is washed with water and coated and modified, a pole piece is prepared, and the compaction density of the pole piece is only 3.52g/cm3Assembling a CR2032 button cell, and testing the electrochemical performance, wherein the electrochemical performance is as follows:
the first coulombic efficiency is 87%, the 0.1C circulation capacity is 203mAh/g, the volume energy density is 2643Wh/L, after 100 times of circulation, the capacity retention rate is 93.2%, and the 10C circulation capacity is 77 mAh/g.
The present specification and figures are to be regarded as illustrative rather than restrictive, and it is intended that all such alterations and modifications that fall within the true spirit and scope of the invention, and that all such modifications and variations are included within the scope of the invention as determined by the appended claims without the use of inventive faculty.

Claims (10)

1. A preparation method of a large (010) crystal face nickel-cobalt-manganese/aluminum layered cathode material is characterized by comprising the following steps:
1) preparing crystal nucleus; inorganic salt or organic salt of nickel, cobalt and/or manganese and aluminum is used as a raw material, and a micro-controlled coprecipitation method is adopted to prepare flaky crystal nuclei with good dispersibility, wherein more than 90% of crystal nuclei in the crystal nuclei have the size not less than 2 mu m, and the spacing between more than 90% of the crystal nuclei is not less than 2 mu m;
2) preparing a precursor; performing coprecipitation reaction by using the crystal nucleus prepared in the step 1) as a substrate, and controlling the growth of a wafer in the thickness direction to obtain a hydroxide precursor with a large crystal face area of (010), wherein the size of more than 90% of primary particles in the precursor with the size of not less than 3 mu m is not less than 3 mu m, and the size of the length and the width of the crystal face of more than 90% of the primary particles (010) is not less than 2 mu m;
3) preparing a positive electrode material; mixing the precursor prepared in the step 2) with a lithium-containing compound and/or inorganic salt or organic salt of manganese and aluminum, and calcining at high temperature to obtain the nickel-cobalt-manganese/aluminum layered cathode material.
2. The method for preparing the large (010) crystal face nickel-cobalt-manganese/aluminum layered cathode material as claimed in claim 1, wherein the area of the crystal face of more than 90% of primary particles (010) in the precursor is not less than 6 μm2。
3. The preparation method of the large (010) crystal face nickel-cobalt-manganese/aluminum layered cathode material as claimed in claim 1, wherein the micro-controlled co-precipitation method in step 1) comprises the following steps:
under the atmosphere of inert gas, dropwise adding inorganic salt or organic salt solution of nickel, cobalt and/or manganese and aluminum, a precipitator and a complexing agent into a reaction kettle containing bottom water at a certain speed respectively, controlling the pH value in the reaction kettle to be 8.0-10.0, preferably 10.0, controlling the ammonia concentration in the reaction kettle to be 2.0-7.0mol/L, preferably 3.0-4.0mol/L, controlling the dropwise adding speed of the inorganic salt or organic salt solution of nickel, cobalt and/or manganese and aluminum to be 0.05-1.0 ml/min, preferably 0.3-0.5 ml/min, and reacting at the temperature of 40-60 ℃ for 1-5 hours to obtain crystal nuclei.
4. The preparation method of the large (010) crystal face nickel-cobalt-manganese/aluminum layered cathode material as claimed in claim 1, wherein the coprecipitation reaction operation process in the step 2) is as follows:
dropwise adding inorganic salt or organic salt solution of nickel, cobalt and/or manganese and aluminum, a precipitator and a complexing agent into a reaction kettle, controlling the dropwise adding speed of the inorganic salt or organic salt solution of nickel, cobalt and/or manganese and aluminum and the precipitator to be 3.0-5.0ml/min, controlling the pH value in the reaction kettle to be 10.5-12.0, preferably 11.2, controlling the ammonia concentration in the reaction kettle to be 0.1-1.0mol/L, preferably 0.3-0.4mol/L, reacting for 30-60 hours at the temperature of 40-60 ℃ to obtain hydroxide slurry, and washing and drying the hydroxide slurry to obtain a precursor.
5. The preparation method of the nickel-cobalt-manganese/aluminum layered cathode material with the large (010) crystal face as claimed in claim 3 or 4, wherein the molar concentration of the inorganic salt or organic salt solution of nickel, cobalt and/or manganese and aluminum is 1.0-3.0mol/L, the molar concentration of the precipitant is 2.0-6.0mol/L, and the molar concentration of the complexing agent is 5.0-15.0 mol/L.
6. The method for preparing the large (010) crystal face nickel-cobalt-manganese/aluminum layered cathode material as claimed in claim 3, 4 or 5, wherein the precipitant is NaOH solution, the complexing agent is ammonia solution, and the bottom water is solution containing ammonia.
7. The preparation method of the nickel cobalt manganese/aluminum layered cathode material with the large (010) crystal face as claimed in claim 1, wherein the inorganic salt or organic salt solution of manganese and aluminum is added in step 1) or step 3).
8. The preparation method of the large (010) crystal face nickel-cobalt-manganese/aluminum layered cathode material according to claim 1, wherein the size of more than 90% primary particles in the layered cathode material is not less than 3 μm, and the length and width of the crystal face of more than 90% primary particles (010) are not less than 2 μm; preferably more than 90% of the crystal face area of the primary particles (010) is not less than 6 mu m2。
9. The method for preparing the nickel-cobalt-manganese/aluminum layered cathode material with the large (010) crystal face according to claim 1, wherein the step 3) of calcining by a sectional calcining process comprises the following steps:
the first stage calcination temperature is 400-;
the second-stage calcination temperature is 700-;
it is preferable that a certain amount of oxygen is added during the calcination when the molar percentage of nickel atoms in the positive electrode material is not less than 60%.
10. The preparation method of the large (010) crystal face nickel-cobalt-manganese/aluminum layered cathode material is characterized in that the inorganic salt or organic salt of nickel and cobalt and/or manganese and aluminum is sulfate, nitrate, chloride or acetate; the lithium-containing compound is one or more of lithium hydroxide, lithium carbonate, lithium acetate and lithium nitrate.
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