High / low-temperature-resistant high-power ternary positive electrode material and preparation method thereof

Abstract

The invention provides a high-power ternary positive electrode material resistant to high and low temperatures. The ternary positive electrode material comprises the following materials: a ternary precursor, a lithium fast ion conductor layer and a three-dimensional graphene network, the thickness of the lithium fast ion conductor layer is 5-20 nm, and the porosity of the three-dimensional graphene network is 70-90%. According to the high-low-temperature-resistant high-power ternary positive electrode material provided by the invention, the performance bottleneck is broken through: LiAlBO3 and three-dimensional graphene are creatively and synergistically coated, the limitation of a single coating is broken through, a traditional coating can only improve single conductivity, and the interface impedance is reduced by more than 30% by constructing an ion-electron dual-path, so that the performance of the ternary positive electrode material is improved. The comprehensive performance of the ternary positive electrode material is greatly improved, the charging and discharging efficiency of the battery is higher and the energy loss is lower in a high and low temperature environment, the improvement of the performance of the lithium ion battery is powerfully promoted, and the urgent demand of the new energy industry on the high-performance battery material is met.

Description

Technical Field

[0001] The present invention relates to the field of cathode materials for lithium-ion batteries, and particularly to a high-power ternary cathode material with high and low temperature resistance and a preparation method thereof. Background Art

[0002] Under the background of the booming development of the new energy industry today, lithium-ion batteries have become the core power source in fields such as electric vehicles and energy storage systems due to advantages such as high energy density and long cycle life. Among them, ternary cathode materials occupy an important position in the market of cathode materials for lithium-ion batteries because of their relatively high specific capacity and voltage platform.

[0003] However, with the continuous expansion of application scenarios and the increasing improvement of usage requirements, many problems have emerged in existing ternary cathode materials.

[0004] Poor low-temperature performance: In a low-temperature environment, the migration rate of lithium ions in the electrode material decreases sharply. This is mainly because low temperature increases the migration activation energy of lithium ions, making it difficult for them to move quickly in the lattice of the electrode material. At the same time, the viscosity of the electrolyte also increases, further hindering the transport of lithium ions. This reduction in the migration rate directly leads to a significant attenuation of the battery capacity;

[0005] Insufficient high-temperature stability: When the battery is in a high-temperature environment, the electrolyte will decompose, generating corrosive substances such as HF. HF will chemically react with the surface of the cathode material, corroding the surface structure of the cathode, resulting in the dissolution of transition metal ions in the cathode material. These dissolved transition metal ions will further catalyze the decomposition of the electrolyte, forming a vicious cycle, thereby greatly reducing the cycle life of the battery;

[0006] Limitations of single coatings: To improve the performance of ternary cathode materials, the traditional method is to use a single coating for modification, such as Li2O·2B2O3 or graphene coatings. The Li2O·2B2O3 coating mainly focuses on improving the ionic conductivity of the material. It can reduce the migration resistance of lithium ions on the surface of the material to a certain extent, but the effect of improving the electronic conductivity is limited. While the graphene coating has excellent electronic conductivity and can enhance the electron transport ability of the material, it performs poorly in improving ionic conductivity.

[0007] Therefore, it is necessary to provide a high-power ternary cathode material with high and low temperature resistance to solve the above technical problems. Summary of the Invention

[0008] The present invention provides a high-power ternary cathode material with high and low temperature resistance, which solves the problems of improving the lithium ion migration rate at low temperature, alleviating capacity attenuation, enhancing the stability of the cathode material at high temperature, reducing the corrosion of electrolyte decomposition products, prolonging the cycle life, breaking through the limitation of a single coating, improving the ionic and electronic conductivity at the same time, and taking into account the high and low temperature performance of the existing ternary cathode material.

[0009] To solve the above technical problems, a high-power ternary cathode material with high and low temperature resistance provided by the present invention includes the following materials:

[0010] Ternary precursor, lithium fast ion conductor layer and three-dimensional graphene network;

[0011] The thickness of the lithium fast ion conductor layer is 5-20 nm, and the porosity of the three-dimensional graphene network is 70-90%.

[0012] A preparation method of a high-power ternary cathode material with high and low temperature resistance, such as the high-power ternary cathode material with high and low temperature resistance, includes the following steps:

[0013] S1. Precursor modification: Mix the ternary precursor with the graphene oxide dispersion liquid and self-assemble it into a three-dimensional porous structure by hydrothermal method;

[0014] S1. Synchronous coating: Introduce an aluminum source and a boron source during the lithium sintering process, and generate a lithium fast ion conductor layer through a solid-phase reaction under the protection of an inert gas to achieve the coordination of doping and coating.

[0015] Preferably, a hydrothermal device will be used in the hydrothermal method operation in S1. The hydrothermal device includes a hydrothermal reaction kettle body, a reaction kettle cover, two connection components and two conveying devices. The reaction kettle cover is arranged on the top of the hydrothermal reaction kettle body, the two connection components are symmetrically arranged on both sides of the surface of the reaction kettle cover, and the two conveying devices are respectively arranged on one side of the two connection components.

[0016] Preferably, the connection component includes a connecting pipe, a communicating thread sleeve, a communicating thread head and a valve. The connecting pipe is connected to the surface of the reaction kettle cover, the threaded communicating sleeve is connected to one end of the connecting pipe, and the communicating thread head is threadedly connected to one end of the communicating thread sleeve.

[0017] Preferably, the valve is arranged on the surface of the connecting pipe.

[0018] Preferably, the conveying device includes a box body, a box cover, a pump body, two conveying pipes and a filling pipe. The box cover is arranged on the top of the box body, and the pump body is installed on the surface of the box cover.

[0019] Preferably, the two conveying pipes are respectively connected to the input end and the output end of the pump body, the filling pipe is installed on one side of the surface of the box cover, and one end of one of the conveying pipes is connected to one end of the communicating threaded head.

[0020] Preferably, a connecting frame is provided between the hydrothermal reactor main body and the two boxes.

[0021] Preferably, a disassembly component is provided between the hydrothermal reactor main body and the two boxes. The disassembly component includes a disassembly hoop, two fixing rings, rubber pads, two rectangular blocks and two bolts. The disassembly hoop is sleeved on the surface of the hydrothermal reactor main body, and the two fixing rings are respectively sleeved on the surfaces of the two boxes and are connected to the disassembly hoop through connecting blocks.

[0022] Preferably, the rubber pads are arranged inside the disassembly hoop, the two rectangular blocks are symmetrically arranged on both sides of the disassembly hoop, and the two bolts are arranged between the two rectangular blocks.

[0023] Compared with the related art, a high-power ternary cathode material with high and low temperature resistance provided by the present invention has the following beneficial effects:

[0024] The present invention provides a high-power ternary cathode material with high and low temperature resistance, which breaks through the performance bottleneck: creatively combines LiAlBO3 and three-dimensional graphene for co - coating, breaking through the limitation of a single coating. The traditional coating can only improve single conductivity, while this patent constructs an "ion - electron double pathway", reducing the interfacial impedance by more than 30%. This greatly improves the comprehensive performance of the ternary cathode material. In high and low temperature environments, the battery has higher charge and discharge efficiency and lower energy loss, strongly promoting the improvement of the performance of lithium - ion batteries and meeting the urgent needs of the new energy industry for high - performance battery materials;

[0025] Explores a new technical direction: the novel composite coating structure has not been publicly reported, opening up a new path for the research of cathode materials. This innovative structure performs excellently in inhibiting electrolyte corrosion and stabilizing the cathode structure. The amount of transition metal dissolution inhibited by LiAlBO3 is <1%, and graphene delays the decomposition of the electrolyte, enabling the battery to maintain a capacity retention rate of 92% after 500 cycles at 55°C in high temperature cycling, significantly extending the battery cycle life, providing new ideas for subsequent material research and development, and is expected to lead the technological innovation in the industry;

[0026] High industrial application value: The process is compatible with existing production lines, greatly reducing the cost and risk for enterprises to apply new technologies. Enterprises can quickly upgrade their products without large-scale transformation of production lines. This material is applicable to fields such as new energy vehicles and energy storage. In new energy vehicles, it can broaden the battery operating temperature range to -40°C to 60°C, improving the vehicle's endurance and performance in different environments; in the energy storage field, it can enhance the stability and service life of energy storage systems, promoting the large-scale development of the new energy industry. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 FIG. is a schematic structural diagram of a second embodiment of a high-power ternary cathode material with high and low temperature resistance and its preparation method provided by the present invention;

[0028] Figure 2 is Figure 1 an enlarged schematic view of part A shown in;

[0029] Figure 3 is Figure 1 a three-dimensional structural schematic diagram of the hydrothermal reaction kettle shown in;

[0030] Figure 4 FIG. is a schematic structural diagram of a third embodiment of a high-power ternary cathode material with high and low temperature resistance and its preparation method provided by the present invention.

[0031] Reference numerals in the figure: 1. Main body of the hydrothermal reaction kettle; 2. Reaction kettle cover;

[0032] 3. Connection assembly; 31. Connecting pipe; 32. Connecting threaded sleeve; 33. Connecting threaded head; 34. Valve;

[0033] 4. Conveying device; 41. Box body; 42. Box cover; 43. Pump body; 44. Conveying pipe; 45. Filling pipe;

[0034] 5. Connecting frame;

[0035] 6. Disassembly assembly; 61. Disassembly hoop; 62. Fixed ring; 63. Rubber pad; 64. Rectangular block; 65. Bolt. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0036] The present invention will be further described below in conjunction with the drawings and embodiments.

[0037] First Embodiment

[0038] A high-power ternary cathode material with high and low temperature resistance includes the following materials:

[0039] Ternary precursor, lithium fast ion conductor layer, and three-dimensional graphene network;

[0040] The thickness of the lithium fast ion conductor layer is 5-20 nm, and the porosity of the three-dimensional graphene network is 70-90%.

[0041] A preparation method of a high-power ternary cathode material resistant to high and low temperatures, such as the high-power ternary cathode material resistant to high and low temperatures, includes the following steps:

[0042] S1. Precursor modification: Mix the ternary precursor with the graphene oxide dispersion liquid and self-assemble it into a three-dimensional porous structure by hydrothermal method;

[0043] S1. Synchronous coating: Introduce an aluminum source and a boron source during the lithiation sintering process, and generate a lithium fast ion conductor layer through a solid-phase reaction under the protection of an inert gas to achieve the synergy of doping and coating.

[0044] Lithium fast ion conductor layer: The lithium fast ion conductor layer (with a thickness of 5-20 nm) is uniformly coated on the surface of the ternary material to provide a fast Li + diffusion channel and inhibit the corrosion of the electrolyte;

[0045] Three-dimensional graphene network: Using a porous graphene aerogel as the framework to construct a continuous electron transport path, relieve particle fragmentation and enhance mechanical strength;

[0046] Synergistic effect: The lithium fast ion conductor layer fills the pores between the graphene layers to form an "ion-electron double pathway", reducing the interfacial impedance (by more than 30%).

[0047] Material preparation:

[0048] Ball-mill and mix the NCM811 precursor with graphene oxide (mass ratio 10:1), add ammonia water to adjust the pH to 9, and perform a hydrothermal reaction at 180 °C for 12 h to obtain a three-dimensional graphene composite precursor;

[0049] Mix the precursor with LiOH·H2O, Al(NO3)3, and H3BO3 (molar ratio 1:0.05:0.05), and sinter at 750 °C for 10 h under a nitrogen atmosphere to obtain the LiAlBO3 / three-dimensional graphene-coated NCM material.

[0050] Performance test:

[0051] Low-temperature performance: The discharge capacity at 0.5C at -30 °C is 158 mAh / g, which is 55% higher than that of the uncoated material (102 mAh / g);

[0052] High-temperature cycling: The capacity retention rate after 500 cycles at 1C at 55 °C is 92%, which is better than that of single LiAlBO3 coating (78%) and pure graphene composite (85%).

[0053] Compared with the related art, the high-low temperature resistant high-power ternary positive electrode material provided by the present invention has the following beneficial effects:

[0054] The present invention provides a high-power ternary cathode material that is resistant to high and low temperatures, breaking through the performance bottleneck: creatively synergistically coating LiAlBO3 with three-dimensional graphene to break the limitation of a single coating. Traditional coatings can only improve single conductivity, while this patent reduces the interface impedance by more than 30% by constructing an "ion-electron dual pathway", which greatly improves the comprehensive performance of the ternary cathode material. In high and low temperature environments, the battery charging and discharging efficiency is higher and the energy loss is lower, which effectively promotes the improvement of lithium-ion battery performance and meets the urgent demand of the new energy industry for high-performance battery materials.

[0055] Opening up new technical directions: The novel composite coating structure has not been publicly reported, and has opened up a new path for the research of positive electrode materials. This innovative structure performs well in inhibiting electrolyte corrosion and stabilizing the positive electrode structure. LiAlBO3 inhibits the dissolution of transition metals by less than 1%, and graphene delays the decomposition of the electrolyte, so that the battery has a capacity retention rate of 92% after 500 cycles at a high temperature of 55°C, significantly extending the battery cycle life, providing new ideas for subsequent material research and development, and is expected to lead the industry's technological innovation;

[0056] High industrial application value: The process is compatible with existing production lines, which greatly reduces the cost and risk of enterprises applying new technologies. Enterprises can quickly upgrade their products without large-scale transformation of production lines. This material is suitable for new energy vehicles, energy storage and other fields. In new energy vehicles, it can expand the battery operating temperature range to -40℃ to 60℃, and improve the vehicle's endurance and performance in different environments; in the field of energy storage, it can improve the stability and service life of the energy storage system, and promote the large-scale development of the new energy industry.

[0057] Second embodiment

[0058] Please refer to Figure 1 , Figure 2 and Figure 3 Based on the method for preparing a high-low temperature resistant high-power ternary positive electrode material provided in the first embodiment of the present application, the second embodiment of the present application proposes another method for preparing a high-low temperature resistant high-power ternary positive electrode material. The second embodiment is only a preferred method of the first embodiment, and the implementation of the second embodiment will not affect the independent implementation of the first embodiment.

[0059] Specifically, the difference in the preparation method of a high-power ternary cathode material resistant to high and low temperatures provided by the second embodiment of the present application lies in that in the hydrothermal method operation in S1, a hydrothermal device will be used. The hydrothermal device includes a hydrothermal reactor main body 1, a reactor cover 2, two connection components 3, and two conveying devices 4. The reactor cover 2 is arranged on the top of the hydrothermal reactor main body 1. The two connection components 3 are symmetrically arranged on both sides of the surface of the reactor cover 2. The two conveying devices 4 are respectively arranged on one side of the two connection components 3.

[0060] The connection component 3 includes a connecting pipe 31, a communicating threaded sleeve 32, a communicating threaded head 33, and a valve 34. The connecting pipe 31 is connected to the surface of the reactor cover 2. The threaded communicating sleeve 32 is connected to one end of the connecting pipe 31. The communicating threaded head 33 is threadedly connected to one end of the communicating threaded sleeve 32.

[0061] The valve 34 is arranged on the surface of the connecting pipe 31.

[0062] The valve 34 can control the use of the connecting pipe 31. The communicating threaded sleeve 32 and the communicating threaded head 33 facilitate the installation and disassembly between the connecting pipe 31 and one of the conveying pipes 44.

[0063] The conveying device 4 includes a box body 41, a box cover 42, a pump body 43, two conveying pipes 44, and a filling pipe 45. The box cover 42 is arranged on the top of the box body 41. The pump body 43 is installed on the surface of the box cover 42.

[0064] The two conveying pipes 44 are respectively connected to the input end and the output end of the pump body 43. The filling pipe 45 is installed on one side of the surface of the box cover 42. One end of one of the conveying pipes 44 is connected to one end of the communicating threaded head 33.

[0065] The other conveying pipe 44 penetrates through the box cover 42 and extends into the interior of the box body 41.

[0066] A connecting frame 5 is arranged between the hydrothermal reactor main body 1 and the two box bodies 41.

[0067] The working principle of the preparation method of a high-power ternary cathode material resistant to high and low temperatures provided by the present invention is as follows:

[0068] During use, when transporting raw materials into the interior of the hydrothermal reactor main body 1, first open the valves 34 on the two connecting pipes 31. After the valves 34 are opened, start the pump body 43 to transport the raw materials inside the box body 41 through the two conveying pipes 44, the communicating threaded sleeve 32, and the communicating threaded head 33 into the interior of the connecting pipe 31. When the raw materials are transported into the interior of the connecting pipe 31, then use the pressure of the pump body 43 to transport the connecting pipe 31 into the interior of the hydrothermal reactor main body 1. After the raw materials are transported into the interior of the hydrothermal reactor main body 1, close the valve 34 on the connecting pipe 31 and it can be used.

[0069] Compared with the related art, a preparation method of a high-power ternary cathode material with high and low temperature resistance provided by the present invention has the following beneficial effects:

[0070] The present invention provides a high-power ternary cathode material with high and low temperature resistance. Connecting pipes 31, communicating threaded sleeves 32, communicating threaded heads 33, and valves 34 are arranged on both sides of the surface of the hydrothermal reactor main body 1 with a reaction kettle cover 2, and are used in cooperation with the box body 41, the box cover 42, the pump body 43, the two conveying pipes 44, and the filling pipe 45. When adding raw materials into the interior of the hydrothermal reactor main body 1, it is convenient to perform the feeding operation through an automatic conveying method, thereby increasing the convenience of use of the entire device.

[0071] Third Embodiment

[0072] Please refer to Figure 4 , based on a preparation method of a high-power ternary cathode material with high and low temperature resistance provided by the first embodiment of the present application, the third embodiment of the present application proposes another preparation method of a high-power ternary cathode material with high and low temperature resistance. The third embodiment is only a preferred method of the first embodiment, and the implementation of the third embodiment will not affect the independent implementation of the first embodiment.

[0073] Specifically, the difference of a preparation method of a high-power ternary cathode material with high and low temperature resistance provided by the third embodiment of the present application is that between the hydrothermal reactor main body 1 and the two box bodies 41, a disassembly assembly 6 is provided. The disassembly assembly 6 includes a disassembly hoop 61, two fixing rings 62, a rubber pad 63, two rectangular blocks 64, and two bolts 65. The disassembly hoop 61 is sleeved on the surface of the hydrothermal reactor main body 1, and the two fixing rings 62 are respectively sleeved on the surfaces of the two box bodies 41 and are connected to the disassembly hoop 61 through connecting blocks.

[0074] The rubber pad 61 is arranged inside the disassembly hoop 61, the two rectangular blocks 64 are symmetrically arranged on both sides of the disassembly hoop 61, and the two bolts 65 are arranged between the two rectangular blocks 64.

[0075] On one side of the disassembly hoop 61, there is an open mouth for convenient sleeving on the surface of the hydrothermal reaction kettle body 1. Two rectangular blocks 64 are connected to both sides of the open mouth. Installation through holes adapted to the bolts 65 are provided on the two rectangular blocks 64. The use of the rubber pad 63 facilitates increasing friction when the disassembly hoop 61 is sleeved on the surface of the hydrothermal reaction kettle body 1.

[0076] The working principle of a preparation method of a high-power ternary cathode material resistant to high and low temperatures provided by the present invention is as follows:

[0077] During use, when fixing between the hydrothermal reaction kettle body 1 and the two boxes 41, first, the disassembly hoops 61 with two fixing rings 62 and rubber pads 63 are respectively sleeved on the surfaces of the two boxes 41 and the hydrothermal reaction kettle body 1. After installing the disassembly hoops 61 with two fixing rings 62 and rubber pads 63, then use two bolts 65 to pass through the two rectangular blocks 64 on one side of the disassembly hoop 61 and tighten the disassembly hoop 61.

[0078] Compared with the related technology, a preparation method of a high-power ternary cathode material resistant to high and low temperatures provided by the present invention has the following beneficial effects:

[0079] The present invention provides a high-power ternary cathode material resistant to high and low temperatures. A disassembly hoop 61, two fixing rings 62, rubber pads 63, two rectangular blocks 64 and two bolts 65 are arranged between the hydrothermal reaction kettle body 1 and the two boxes 41, which facilitates the fixed splicing and disassembly between the hydrothermal reaction kettle body 1 and the two boxes 41.

[0080] The above are only the embodiments of the present invention, and do not limit the patent scope of the present invention accordingly. All equivalent structural or equivalent process transformations made by using the content of the specification and drawings of the present invention, or directly or indirectly applied in other related technical fields, are equally included in the patent protection scope of the present invention.

Claims

1. A high-power ternary cathode material resistant to high and low temperatures, characterized in that, It includes the following materials: Ternary precursor, lithium fast ion conductor layer and three-dimensional graphene network; The thickness of the lithium fast ion conductor layer is 5 - 20 nm, and the porosity of the three-dimensional graphene network is 70 - 90%.

2. A preparation method of a high-power ternary cathode material resistant to high and low temperatures, the high-power ternary cathode material resistant to high and low temperatures as described in claim 1, characterized in that, It includes the following steps: S1. Precursor modification: Mix the ternary precursor with the graphene oxide dispersion liquid and self-assemble it into a three-dimensional porous structure by hydrothermal method; S1. Synchronous coating: Introduce aluminum source and boron source during the lithiation sintering process, and generate a lithium fast ion conductor layer through solid-phase reaction under the protection of inert gas to achieve the synergy of doping and coating.

3. The preparation method of the high-power ternary cathode material resistant to high and low temperatures according to claim 2, characterized in that In the hydrothermal method operation in S1, a hydrothermal device will be used. The hydrothermal device includes a hydrothermal reaction kettle body, a reaction kettle cover, two connection components and two conveying devices. The reaction kettle cover is arranged on the top of the hydrothermal reaction kettle body. The two connection components are symmetrically arranged on both sides of the surface of the reaction kettle cover, and the two conveying devices are respectively arranged on one side of the two connection components.

4. The preparation method of the high-power ternary cathode material resistant to high and low temperatures according to claim 2, characterized in that, The connection component includes a connecting pipe, a communicating threaded sleeve, a communicating threaded head and a valve. The connecting pipe is connected to the surface of the reaction kettle cover. The threaded communicating sleeve is connected to one end of the connecting pipe, and the communicating threaded head is threadedly connected to one end of the communicating threaded sleeve.

5. The preparation method of the high-power ternary cathode material with high and low temperature resistance according to claim 4, characterized in that, The valve is arranged on the surface of the connecting pipe.

6. The preparation method of the high-power ternary cathode material with high and low temperature resistance according to claim 4, characterized in that, The conveying device includes a box body, a box cover, a pump body, two conveying pipes and a filling pipe. The box cover is arranged on the top of the box body, and the pump body is installed on the surface of the box cover.

7. The preparation method of the high-power ternary cathode material with high and low temperature resistance according to claim 6, characterized in that, The two conveying pipes are respectively connected to the input end and the output end of the pump body. The filling pipe is installed on one side of the surface of the box cover, and one end of one of the conveying pipes is connected to one end of the communicating threaded head.

8. The preparation method of the high-power ternary cathode material resistant to high and low temperatures according to claim 6, characterized in that, A connecting frame is arranged between the hydrothermal reaction kettle body and the two box bodies.

9. The preparation method of the high-power ternary cathode material resistant to high and low temperatures according to claim 6, wherein, A disassembly component is arranged between the hydrothermal reaction kettle body and the two box bodies. The disassembly component includes a disassembly hoop, two fixing rings, a rubber pad, two rectangular blocks and two bolts. The disassembly hoop is sleeved on the surface of the hydrothermal reaction kettle body. The two fixing rings are respectively sleeved on the surfaces of the two box bodies and are connected to the disassembly hoop through connecting blocks.

10. The preparation method of the high-power ternary cathode material with high and low temperature resistance according to claim 9, characterized in that, The rubber pad is arranged inside the disassembly hoop. The two rectangular blocks are symmetrically arranged on both sides of the disassembly hoop, and the two bolts are arranged between the two rectangular blocks.

Images