CN116072843A - A kind of coating material of single crystal lithium manganese oxide coated nickel cobalt lithium manganese oxide and its production method and application - Google Patents

Abstract

The invention discloses a coating material of monocrystal lithium manganate coated nickel cobalt lithium manganate, a production method and application thereof, belonging to the technical field of lithium ion battery materials; the coating material of the monocrystal lithium manganate coated nickel cobalt lithium manganate comprises monocrystal lithium manganate and nickel cobalt lithium manganate; the single crystal lithium manganate with smaller particles is used as the coating, so that the safety of the nickel cobalt lithium manganate material can be effectively improved, the coating can be uniformly distributed by further adopting a wet coating process, and the cycle, high temperature and safety performance of the coating material can be effectively improved.

Description

A coating material of single crystal lithium manganese oxide coated nickel cobalt lithium manganese oxide and its production method and application

technical field

The invention relates to the technical field of lithium-ion battery materials, in particular to a single-crystal lithium manganate-coated nickel-cobalt-lithium-manganese-oxide coating material and a production method and application thereof.

Background technique

As a new energy industry, lithium-ion batteries have been promoted all over the world and are widely used in digital products, electric tools, electric vehicles and electric vehicles. Among them, the process innovation of cathode materials has always been the focus of research and development direction in the industry.

At present, several materials such as lithium cobalt oxide, lithium nickel cobalt manganese oxide, lithium iron phosphate, and lithium manganese oxide are generally used in the field of positive electrode materials for lithium-ion batteries. (LiNi _x Co _y Mn _1-xy O ₂ ) has high energy density, voltage plateau, rate, cycle, high temperature and other properties.

However, the thermal stability of nickel-cobalt lithium manganese oxide material is poor, and the chemical reaction is strong at high temperature, which is easy to cause spontaneous combustion. Its safety performance has always limited the development of the material end. The safe process is of great significance to the application of nickel cobalt lithium manganate material.

Contents of the invention

The technical problem to be solved by the present invention is to overcome the defects of the prior art, to provide a single crystal lithium manganate coated nickel cobalt lithium manganese oxide coating material and its production method and application, using single crystal manganese acid with smaller particles Lithium is used as a coating, which can effectively improve the safety of nickel-cobalt-lithium manganese oxide material. Further use of wet coating process can make the coating evenly distributed, and can effectively improve the cycle, high temperature and safety performance of the coating material.

In order to achieve the above-mentioned purpose of the invention, the embodiment of the present invention adopts the following technical solutions:

The invention discloses a cladding material of nickel-cobalt lithium manganese oxide coated with single crystal lithium manganese oxide. The cladding material includes single crystal lithium manganese oxide and lithium nickel cobalt manganese oxide.

The embodiment of the present invention also provides a production method of the coating material of the above-mentioned single crystal lithium manganese oxide coated nickel cobalt lithium manganese oxide, comprising the following steps:

(1) Place single crystal lithium manganese oxide in a grinding device and grind for 60-180s to obtain material A;

(2) Put nickel-cobalt lithium manganese oxide material, alumina balls and deionized water in a ball mill and mix them for 20-40 minutes;

(3) Add material A of step (1) to step (2) and mix for 60-120 minutes to obtain material B;

(4) After filtering the alumina balls in the material B, enter the stirring device, stir and spray dry at the same time, until the stirring is completed until the spray drying process is completed, and the material C is obtained;

(5) After the material C in the step (4) is sintered, crushed, sieved, and iron is removed, a single-crystal lithium manganate-coated nickel-cobalt-lithium manganese-coated material is obtained.

Further, the particle size of the material A in the step (1) is 2-6 μm.

Further, the grinding device in the step (1) is a high-speed grinding machine.

Further, the mass ratio of nickel cobalt lithium manganate material in the step (2): alumina ball: deionized water is (0.5-1.5): (0.5-1.5): 2; the particle size of the alumina ball The diameter is 20-40mm.

Further, the ball mill in the step (2) is a horizontal ball mill with a rotating speed of 60-80 R/min.

Further, the rotating speed in the step (3) is 20-40 R/min.

Further, the mass ratio of material A to nickel-cobalt-manganese acid in the step (3) is (0.5-1.5):1000.

Further, in the step (4), the stirring speed is 30-50 R/min; the spray drying temperature is 260-280°C.

Further, the sintering temperature in the step (5) is 300-650° C. and the time is 4-8 hours.

Further, the mesh size of the sieve in the step (5) is 200-400.

The embodiment of the present invention also provides the single crystal manganese produced by the coating material of single crystal lithium manganate coated nickel cobalt lithium manganate or the production method of the single crystal lithium manganate coated nickel cobalt lithium manganate The application of the coating material of nickel-cobalt-lithium-manganese oxide-coated nickel-cobalt lithium-manganese oxide in battery positive electrode materials.

Compared with prior art, the beneficial effect of the present invention is:

(1) The present invention uses single crystal lithium manganese oxide as the coating, and the coating effect is better. The coating can be evenly distributed to the surface of the coating material at low temperature, so that it can be tightly combined, and the coating layer forms an effective protective film after cooling ;Single crystal lithium manganese oxide has a strong resistance to hydrofluoric acid corrosion, thereby effectively reducing the violent reaction of the material at high temperature, making the material more thermally stable; Lithium oxide can achieve the effect of complementary advantages, so that the coating material has higher voltage stability and safety.

(2) The present invention provides the production method of the coating material of monocrystalline lithium manganese oxide coated nickel cobalt lithium manganese oxide, adopts alumina ball as mixing medium, promotes mixing effect; In ball milling process, used two kinds of different rotating speeds , the purpose of the first stage is to disperse the raw materials evenly, and the speed is relatively high; the purpose of the second stage is to coat the material, and the speed is relatively low; the purpose of setting up the stirring device is to prevent the precipitation of the raw materials; The uniform distribution of the material can effectively improve the circulation, high temperature and safety performance of the material.

(3) After the coating material of single-crystal lithium manganate-coated nickel-cobalt-lithium manganese oxide of the present invention is made into a battery, the cycle performance can be improved to 75% at room temperature for more than 3,000 cycles at 0.5C, and it can be used in a high-temperature environment Improve battery stability and safety.

Description of drawings

In order to make the purpose of the present invention, technical solutions and advantages clearer, and to explain the technical solutions of the present invention more clearly, the accompanying drawings required in the embodiments will be briefly introduced below. Obviously, the accompanying drawings in the following description The drawings are only some embodiments of the present invention, and those skilled in the art can also obtain other drawings based on these drawings without creative work.

FIG. 1 is a 500-fold scanning electron microscope of the coating material of the single-crystal lithium manganate-coated nickel-cobalt-lithium manganese oxide in Example 1.

Fig. 2 is a scanning electron microscope at 2000 times of the coating material of the single crystal lithium manganese oxide coated nickel cobalt lithium manganese oxide in Example 1.

Fig. 3 is a scanning electron microscope at 5000 times of the coating material of the single crystal lithium manganese oxide coated nickel cobalt lithium manganese oxide in Example 1.

Fig. 4 is the performance test of charge and discharge after the battery is made from the coating material of single crystal lithium manganese oxide coated nickel cobalt lithium manganese oxide in Example 1.

Detailed ways

In order to make the object, technical solution and advantages of the present invention more clear, the present invention will be further described in detail below in conjunction with the examples. It should be understood that the specific embodiments described here are only used to explain the present invention, not to limit the present invention.

Example 1

An embodiment of the present invention provides a single-crystal lithium manganate-coated nickel-cobalt-lithium manganate coating material, including single-crystal lithium manganate and nickel-cobalt lithium manganate.

The production method of the coating material of the above-mentioned single crystal lithium manganese oxide coated nickel cobalt lithium manganate comprises the following steps:

(1) Take 1 kg of single crystal lithium manganese oxide with a particle size distribution d50 of 9 μm, place it in a high-speed grinder and grind it for 60 seconds, and the obtained material A has a particle size distribution d50 of about 5 μm, and seal it for later use.

(2) Weigh 5 kg of nickel-cobalt lithium manganese oxide material, 5 kg of alumina balls, and 10 kg of deionized water, and put them into a horizontal ball mill in turn at a speed of 80 R/min for 30 minutes; wherein the diameters of alumina balls are 20 mm and 25 mm 2.5kg each.

(3) Weigh 5 g of material A and put it into a horizontal ball mill at a speed of 30 R/min for 120 minutes to obtain material B.

(4) Add a filter screen to the suction filter port, add deionized water and extract it several times, filter the alumina balls in the material B, enter the stirring tank, stir, open the spray drying tower, heat to 250 ° C, The slurry was spray-dried at a stirring speed of 30 R/min until the stirring was completed until the spray-drying process was completed, and material C was obtained.

(5) Place material C in an atmosphere furnace for sintering, raise it to 500°C at a rate of 6°C/min, and keep it warm for 8 hours. During the process, air is introduced at a flow rate of 0.5m ³ /h; After ironing, the coating material of single crystal lithium manganese oxide coating nickel cobalt lithium manganese oxide is obtained.

Scan the cladding material under the condition of 500 times, 2000 times and 8000 times, please refer to the accompanying drawings 1/2/3 for details.

It can be seen from the scanning electron microscope of the finished product in Figure 1/2/3 of the specification that the crystal structure of the material is complete, and the crystal surface has a complete protective layer, which is evenly distributed and has a good coating effect.

Using the soft pack battery process method, the coating materials of single crystal lithium manganese oxide coated nickel cobalt lithium manganese oxide are made into batteries respectively. The battery was tested for charge and discharge performance, and the results are shown in Figure 4.

It can be seen from Figure 4 that the cycle performance test (2.75-4.3V) of charging and discharging at 0.5C rate of the half-point battery can improve the cycle performance to 0.5C at room temperature for more than 3000 cycles. The retention rate is 75%, which is higher than that of conventional materials. (The capacity retention rate of 0.5C cycle at room temperature is 80% in 800-1500 cycles) nearly doubled.

Example 2

An embodiment of the present invention provides a single-crystal lithium manganate-coated nickel-cobalt-lithium manganate coating material, including single-crystal lithium manganate and nickel-cobalt lithium manganate.

The production method of the coating material of the above-mentioned single crystal lithium manganese oxide coated nickel cobalt lithium manganate comprises the following steps:

(1) Take 1 kg of single crystal lithium manganese oxide with a particle size distribution d50 of 9 μm, place it in a high-speed grinder and grind it for 120 s, and obtain material A with a particle size distribution d50 of about 4 μm, and seal it for later use.

(2) Weigh 2.5kg of nickel-cobalt lithium manganese oxide material, 2.5kg of alumina balls, and 10kg of deionized water, and put them into a horizontal ball mill in turn, with a speed of 70R/min and a time of 30min; the diameter of alumina balls selected is 30mm , 35mm each 2.5kg.

(3) Weigh 7.5g of material A and put it into a horizontal ball mill with a rotating speed of 20R/min and a time of 120min to obtain material B.

(4) Add a filter screen to the suction filter port, add deionized water and extract it several times, filter the alumina balls in the material B, enter the stirring tank, stir, open the spray drying tower, heat to 250 ° C, The slurry was spray-dried at a stirring speed of 40 R/min until the stirring was completed until the spray-drying process was completed, and material C was obtained.

(5) Place material C in an atmosphere furnace for sintering, raise it to 500°C at a rate of 6°C/min, and keep it warm for 8 hours. During the process, air is introduced at a flow rate of 0.5m ³ /h; After ironing, the coating material of single crystal lithium manganese oxide coating nickel cobalt lithium manganese oxide is obtained.

Using the soft pack battery process method, the coating materials of single crystal lithium manganese oxide coated nickel cobalt lithium manganese oxide are made into batteries respectively.

Example 3

An embodiment of the present invention provides a single-crystal lithium manganate-coated nickel-cobalt-lithium manganate coating material, including single-crystal lithium manganate and nickel-cobalt lithium manganate.

The production method of the coating material of the above-mentioned single crystal lithium manganese oxide coated nickel cobalt lithium manganate comprises the following steps:

(1) Take 1 kg of single-crystal lithium manganese oxide with a particle size distribution d50 of 9 μm, place it in a high-speed grinder and grind for 180 seconds, and obtain material A with a particle size distribution d50 of about 3 μm, and seal it for later use.

(2) Weigh 7.5kg of nickel-cobalt lithium manganese oxide material, 7.5kg of alumina balls, and 10kg of deionized water, and put them into a horizontal ball mill in turn, with a speed of 80R/min and a time of 30min; the diameter of alumina balls selected is 20mm , 25mm each 2.5kg.

(3) Take 10g of material A and put it into a horizontal ball mill with a rotating speed of 40R/min and a time of 120min to obtain material B.

(4) Add a filter screen to the suction filter port, add deionized water and extract it several times, filter the alumina balls in the material B, enter the stirring tank, stir, open the spray drying tower, heat to 250 ° C, The slurry was spray-dried at a stirring speed of 50 R/min until the stirring was completed until the spray-drying process was completed, and material C was obtained.

(5) Place material C in an atmosphere furnace for sintering, raise it to 500°C at a rate of 6°C/min, and keep it warm for 8 hours. During the process, air is introduced at a flow rate of 0.5m3/h; after sintering, crush, sieve, and remove iron After that, the coating material of single crystal lithium manganese oxide coating nickel cobalt lithium manganese oxide is obtained.

Using the soft pack battery process method, the coating materials of single crystal lithium manganese oxide coated nickel cobalt lithium manganese oxide are made into batteries respectively.

The above description is only a preferred embodiment of the present invention, and is not intended to limit the present invention. Any modification, equivalent replacement or improvement made within the spirit and principles of the present invention shall be included in the protection of the present invention. within range.

Claims (10)

1. The coating material of the monocrystal lithium manganate coated nickel cobalt lithium manganate is characterized by comprising monocrystal lithium manganate and nickel cobalt lithium manganate.

2. The production method of the coating material of the monocrystal lithium manganate coated nickel cobalt lithium manganate is characterized by comprising the following steps:

(1) Placing the monocrystal lithium manganate in a grinding device for grinding for 60-180s to obtain a material A;

(2) Placing a nickel cobalt lithium manganate material, alumina balls and deionized water in a ball milling device, and mixing for 20-40min;

(3) Adding the material A in the step (1) into the step (2) for mixing for 60-120min to obtain a material B;

(4) Filtering the alumina balls in the material B, then, feeding the alumina balls into a stirring device, stirring and drying by spraying at the same time until the stirring is finished in the drying spraying process, and obtaining a material C;

(5) And (3) sintering, crushing, sieving and deironing the material C in the step (4) to obtain the coating material of the monocrystal lithium manganate coated nickel cobalt lithium manganate.

3. The method for producing the single crystal lithium manganate coated nickel cobalt lithium manganate according to claim 2, wherein the particle size of the material A in the step (1) is 2-6 μm; the grinding device is a high-speed grinding machine.

4. The method for producing single crystal lithium manganate coated lithium nickel cobalt manganate according to claim 2, wherein the lithium nickel cobalt manganate material in the step (2): alumina balls: the mass ratio of the deionized water is (0.5-1.5): (0.5-1.5): 2; the particle size of the alumina balls is 20-40mm.

5. The method for producing the single crystal lithium manganate coated nickel cobalt lithium manganate according to claim 2, wherein the ball milling device in the step (2) is a horizontal ball mill with the rotating speed of 60-80R/min.

6. The method for producing the single crystal lithium manganate coated lithium nickel cobalt manganate according to claim 2, wherein the rotating speed in the step (3) is 20-40R/min.

7. The method for producing the single crystal lithium manganate coated nickel cobalt lithium manganate according to claim 2, wherein the mass ratio of the material A to the nickel cobalt manganate in the step (3) is (0.5-1.5): 1000.

8. The method for producing single crystal lithium manganate coated lithium nickel cobalt manganate according to claim 2, wherein the stirring speed in the step (4) is 30-50R/min; the spray drying temperature is 260-280 ℃.

9. The method for producing the single crystal lithium manganate coated nickel cobalt lithium manganate according to claim 2, wherein the sintering temperature in the step (5) is 300-650 ℃ for 4-8 hours.

10. The use of the coating material of single crystal lithium manganate coated nickel cobalt lithium manganate according to claim 1 or the coating material of single crystal lithium manganate coated nickel cobalt lithium manganate according to claim 2-9 in a battery positive electrode material.

Images