Method for preparing hard carbon negative electrode material, use thereof, negative electrode sheet and battery

Abstract

Disclosed in the present inventio are a method for preparing a hard carbon negative electrode material, a use thereof, a negative electrode sheet, and a battery, and provided is a method for rapid and large-scale preparation of a hard carbon material by means of a dielectric barrier discharge (DBD) plasma-assisted sintering technology and transfer. The preparation method has a high temperature rise rate (100-1000°C / min), a short sintering time (20 seconds to 30 minutes), and a low energy consumption, thereby improving the production efficiency of the hard carbon negative electrode material, reducing the energy consumption and cost, and realizing controllable adjustment of the microstructure of the material. Moreover, the method allows for preparation under atmospheric pressure, and by means of a roll-to-roll transfer process, implements rapid and large-scale preparation of the hard carbon negative electrode material, thereby further improving the efficiency of the preparation procedure. In addition, carbon source materials are widely available, the microstructure and doping characteristics of the hard carbon negative electrode material can also be effectively regulated and controlled, and rapid and large-scale preparation of the hard carbon negative electrode material is finally realized. When used as a negative electrode material for a sodium-ion battery, the above hard carbon material can exhibit excellent sodium storage performance.

Description

Preparation method of hard carbon negative electrode material and its application, negative electrode sheet and battery Technical Field

[0001] The present invention relates to the technical field of energy storage materials and devices, and in particular to a preparation method of a hard carbon negative electrode material and its application, a negative electrode sheet and a battery. Background Art

[0002] Lithium-ion batteries are widely used in consumer electronics and energy storage. However, due to the low abundance and high cost of lithium resources, the further large-scale application of lithium-ion batteries is limited. In contrast, sodium resources are abundant and low in cost. Sodium and lithium are elements of the same family and have similar electrochemical properties. Therefore, sodium-ion batteries are considered to be one of the next-generation battery technologies with great application potential. In particular, they have shown significant cost advantages in the field of large-scale energy storage and have also received widespread attention. In sodium-ion batteries, due to the sodium ion More than lithium-ion The significantly larger ionic radius and different solvation structure from lithium ions also limit the selection of anode materials for sodium-ion batteries. However, hard carbon materials are considered to have the most promising application prospects for sodium-ion battery anode materials due to their abundant raw material sources and stable structure.

[0003] In related technologies, hard carbon materials usually need to be prepared using a high-temperature carbonization process. However, the commonly used tubular furnace equipment for preparing hard carbon negative electrode materials generally has shortcomings such as slow heating rate, long sintering time, and high energy consumption, which reduces the production efficiency of hard carbon negative electrodes and increases production costs. While the method of preparing hard carbon negative electrode materials using rapid calcination carbonization technology can meet the requirements for temperature rise rate and sintering time, the above-mentioned carbonization process needs to be carried out under high pressure conditions (20-50MPa), which cannot be achieved for large-scale production.

[0004] Therefore, it is of great significance to solve the shortcomings of slow heating rate, long sintering time and high energy consumption in the preparation process of hard carbon negative electrode materials, and develop a carbonization technology that can be prepared on a large scale and has both low cost and high efficiency to achieve large-scale application of hard carbon negative electrodes for sodium ion batteries.

[0005] Summary of the Invention

[0006] The present invention aims to address at least one of the technical problems existing in the prior art. To this end, the present invention provides a method for preparing a hard carbon anode material, its application, a negative electrode sheet, and a battery. These methods aim to address the current problems of slow heating rates, long sintering times, and high energy consumption associated with the large-scale production of hard carbon anode materials.

[0007] In a first aspect of the present invention, a method for preparing a hard carbon negative electrode material is provided, comprising the steps of:

[0008] S1. providing a carbon source material, drying the carbon source material, and ball-milling the carbon source material to obtain a powdery material;

[0009] S2, pre-carbonizing the powdered material under an inert gas atmosphere, and grinding and crushing the powdered material to obtain a precursor powder;

[0010] S3. Under normal pressure, the precursor powder is fed into a dielectric barrier discharge plasma assisted sintering device using a roll-to-roll process to carbonize the precursor powder to obtain a carbonized material;

[0011] S4. Taking out the carbonized material, grinding and crushing it to obtain the hard carbon negative electrode material.

[0012] The method for preparing hard carbon negative electrode materials according to an embodiment of the present invention has at least the following beneficial effects: the present invention proposes a method for preparing hard carbon negative electrode materials in large quantities by using dielectric barrier discharge plasma (DBD) to assist rapid sintering. On the one hand, it improves the production efficiency of hard carbon negative electrode materials, reduces energy consumption and costs, and realizes controllable adjustment of the material microstructure; on the other hand, combined with the conveying process, it can quickly prepare hard carbon negative electrode materials in large quantities, further improving the efficiency of the preparation process. The conveying rapid carbonization technology of the present invention has a fast temperature rise rate, short sintering time, and low energy consumption; and it does not need to be carried out under high pressure conditions, and can be prepared under normal pressure conditions. Combined with the conveying process, it can realize the large-scale preparation and production of hard carbon negative electrode materials, improve production efficiency, and reduce costs; not only that, the microstructure and doping characteristics of the hard carbon negative electrode materials can be regulated according to DBD discharge parameters, temperature rise rate, sintering time, conveying speed, etc. Finally, the low-cost, high-efficiency rapid carbonization method provided by the present invention can prepare hard carbon negative electrode materials on a large scale, which is of great significance for the large-scale application of hard carbon negative electrodes in sodium ion batteries. The prepared hard carbon materials can be used as negative electrode materials for sodium ion batteries, matched with positive electrode materials and electrolytes, and can exhibit excellent sodium storage performance.

[0013] Figure 1 shows a schematic diagram of the dielectric barrier discharge plasma (DBD)-assisted rapid sintering and large-scale production apparatus proposed in this invention. As shown in the figure, the DBD system generates plasma between dielectric barrier plates, heats the entire plasma region using a heating plate, and simultaneously transports raw materials and prepared hard carbon materials via a winding conveyor, enabling DBD-assisted rapid sintering and large-scale production of hard carbon materials.

[0014] In some embodiments of the present invention, the carbon source material is selected from a mixture of one or more of minerals, biomass, and chemical products.

[0015] In some preferred embodiments of the present invention, the carbon source material is selected from a mixture of one or more of anthracite, sucrose, starch, straw, resin, asphalt, coke, wood, bamboo, and coconut shell.

[0016] The raw materials used in the present invention can be obtained from a wide range of sources, and minerals, biomass and chemical products can be used as carbon sources, including but not limited to a mixture of at least one or more coal or biomass materials such as anthracite, sucrose, starch, straw, resin, asphalt, coke, wood, bamboo, coconut shell, etc.

[0017] Preferably, the carbon source material is selected from starch.

[0018] Preferably, the carbon source material is selected from anthracite. When anthracite is selected as the carbon source material alone, it can also be selected without pre-carbonization treatment.

[0019] In some embodiments of the present invention, in step S1, before drying the carbon source material, an impurity removal step is also included.

[0020] In some embodiments of the present invention, the drying temperature is 50-200°C.

[0021] In some preferred embodiments of the present invention, the drying temperature is 150-200°C.

[0022] In some embodiments of the present invention, the drying process is performed for 1 to 10 hours.

[0023] In some preferred embodiments of the present invention, the drying process lasts for 1 to 2 hours.

[0024] In some embodiments of the present invention, in step S2, the inert atmosphere is argon.

[0025] In some embodiments of the present invention, the temperature of the pre-carbonization treatment is 500-800°C.

[0026] In some preferred embodiments of the present invention, the temperature of the pre-carbonization treatment is 500-550°C.

[0027] More preferably, the temperature of the pre-carbonization treatment is about 500°C.

[0028] In some embodiments of the present invention, the pre-carbonization treatment time is 1 to 10 hours.

[0029] In some preferred embodiments of the present invention, the pre-carbonization treatment time is 2 to 3 hours.

[0030] In the present invention, the powdered material obtained in step S1 is preheated in an inert gas atmosphere at a temperature of 500-800° C. for 1-10 hours, and then the preheated material is ground and pulverized to obtain a black precursor powder, thereby completing the pre-carbonization of the carbon source material.

[0031] In some embodiments of the present invention, in step S3, under normal pressure conditions, the pre-carbonized black precursor powder is placed in a dielectric barrier discharge plasma (DBD) assisted sintering device, combined with a roll-to-roll process, for high-temperature rapid carbonization. The atmosphere inside the device is an inert gas (such as argon), the temperature rise rate is 100 to 1000°C / minute, the sintering temperature is 800 to 1500°C, and the sintering time is 20 seconds to 30 minutes.

[0032] Dielectric barrier discharge plasma technology has reliable, stable, and uniform discharge characteristics. The types and concentrations of high-energy active ions in the discharge plasma can be controlled and adjusted according to actual needs. It is widely used in the fields of material surface treatment, thin film material deposition, coal combustion, etc. In the process of preparing hard carbon, it is often necessary to overcome chemical bonds with high bond energy such as carbon-oxygen, carbon-carbon, and carbon-hydrogen in the carbon source material, which requires the sintering process to have high temperature and high energy consumption. The present invention introduces dielectric barrier discharge plasma technology to assist in sintering to prepare hard carbon materials. The interaction between high-energy particles in the plasma and active groups in the carbon source material is used to affect the chemical equilibrium of the system during the carbonization process, regulate the carbonization process, reduce the carbonization temperature, accelerate the hard carbon preparation process, and reduce energy consumption. At the same time, the present invention uses a roll-to-roll process to feed the precursor powder into a dielectric barrier discharge plasma-assisted sintering device, carbonize the precursor powder, and obtain a carbonized material; the winding speed of the roll-to-roll process is determined according to the required sintering time and the plasma area scale, thereby effectively controlling the sintering time of the hard carbon negative electrode preparation process, further improving production efficiency and reducing costs.

[0033] In some embodiments of the present invention, the power density of the dielectric barrier discharge plasma (DBD) assisted sintering device is 1-10 kW / m 2 .

[0034] In some preferred embodiments of the present invention, the power density of the dielectric barrier discharge plasma (DBD) assisted sintering device is 3-5 kW / m 2 .

[0035] In some embodiments of the present invention, the dielectric barrier plates of the dielectric barrier discharge plasma (DBD) assisted sintering device have a spacing of 1 to 20 mm.

[0036] In some preferred embodiments of the present invention, the distance between the dielectric barrier plates of the dielectric barrier discharge plasma (DBD) assisted sintering device is 3 to 8 mm.

[0037] In some embodiments of the present invention, the temperature rise rate of the dielectric barrier discharge plasma (DBD) assisted sintering device is 100 to 1000° C. / minute.

[0038] In some preferred embodiments of the present invention, the temperature rise rate of the dielectric barrier discharge plasma (DBD) assisted sintering device is 200-500° C. / min.

[0039] In some embodiments of the present invention, the carbonization treatment is performed under an inert gas atmosphere, preferably an argon atmosphere.

[0040] In some embodiments of the present invention, the temperature rise rate of the carbonization treatment is 100-1000° C. / min.

[0041] In some preferred embodiments of the present invention, the temperature rise rate of the carbonization treatment is 200-500° C. / min.

[0042] In some embodiments of the present invention, the sintering temperature of the carbonization treatment is 800-1500°C.

[0043] In some preferred embodiments of the present invention, the sintering temperature of the carbonization treatment is 1000-1300°C.

[0044] In some embodiments of the present invention, the sintering time of the carbonization treatment is 20 seconds to 30 minutes.

[0045] In some preferred embodiments of the present invention, the sintering time of the carbonization treatment is 10 to 25 minutes.

[0046] In some embodiments of the present invention, the roll-to-roll process's winding speed is determined by the desired sintering time and the size of the plasma zone. This allows for the large-scale production of hard carbon materials using a conveyor belt process. The roll-to-roll process's winding speed is determined by the desired sintering time and the size of the plasma zone, effectively controlling the sintering time during the hard carbon anode preparation process, further improving production efficiency and reducing costs.

[0047] In some embodiments of the present invention, in step S4, after naturally cooling to room temperature, the carbonized material is taken out, then ground and pulverized, and screened to obtain the hard carbon material.

[0048] The preparation method of the hard carbon negative electrode material provided by the present invention utilizes dielectric barrier discharge plasma (DBD) to assist in rapid sintering to prepare hard carbon negative electrode materials in large quantities. This preparation method has a fast temperature rise rate (100-1000°C / minute), a short sintering time (20 seconds to 30 minutes), low energy consumption, and does not require high-pressure conditions, and can be prepared under normal pressure conditions; combined with the conveying process, it can realize the rapid and large-scale preparation and production of hard carbon negative electrode materials, improve production efficiency, and reduce costs; the raw materials are widely available, and minerals, biomass and chemical products can be used as carbon sources; not only that, the microstructure and doping characteristics of the hard carbon negative electrode material can be regulated according to the temperature rise rate, sintering time, conveying speed, etc. The hard carbon material prepared by the above method is used as a negative electrode material for sodium ion batteries, showing excellent sodium storage performance.

[0049] In a second aspect of the present invention, a hard carbon negative electrode material is provided. The hard carbon negative electrode material is prepared by the macro-scale preparation method of the hard carbon negative electrode material as described above.

[0050] The hard carbon anode material according to embodiments of the present invention has at least the following beneficial effects: The hard carbon anode material is prepared using a dielectric barrier discharge plasma (DBD)-assisted rapid carbonization method. On the one hand, the raw materials of the present invention are widely available, including minerals, biomass, and chemical products as carbon sources, including but not limited to at least one of coal-based or biomass materials such as anthracite, sucrose, starch, straw, resin, asphalt, coke, wood, bamboo, coconut shell, or a mixture thereof; on the other hand, the microstructure and doping characteristics of the hard carbon anode material can be controlled by DBD discharge parameters, temperature rise rate, sintering time, and conveying speed. When used as a negative electrode material for sodium-ion batteries, the hard carbon material exhibits excellent sodium storage performance when matched with the positive electrode material and electrolyte.

[0051] The third aspect of the present invention provides an application of the large-scale preparation method of the hard carbon negative electrode material as described above in the preparation of battery negative electrode materials.

[0052] According to the application of the embodiment of the present invention, there are at least the following beneficial effects: The present invention proposes a dielectric barrier discharge plasma (DBD) assisted rapid carbonization method for the large-scale preparation of hard carbon negative electrode materials, and realizes its application in the preparation of battery negative electrode materials. This preparation method has a fast temperature rise rate (100-1000℃ / minute), a short sintering time (20 seconds to 30 minutes), and low energy consumption. It can be prepared under normal pressure conditions and can realize the rapid large-scale preparation and production of hard carbon negative electrode materials. In addition, the raw materials are widely available, and the microstructure and doping characteristics of the hard carbon negative electrode material can be effectively controlled according to the temperature rise rate, sintering time, and conveying speed. The above method is applied to the preparation of battery negative electrode materials, which can realize the large-scale preparation and production of negative electrode materials, improve production efficiency, and reduce costs; the prepared hard carbon material is used in secondary batteries such as sodium ion batteries or lithium batteries, and exhibits excellent sodium storage performance.

[0053] In a fourth aspect of the present invention, a negative electrode plate is provided, comprising the hard carbon negative electrode material as described above.

[0054] The negative electrode sheet of the present invention comprises a current collector and a negative electrode material. The negative electrode material comprises a negative electrode active material, a conductive agent, and a binder. The negative electrode active material is the aforementioned hard carbon negative electrode material or a hard carbon negative electrode material prepared using the aforementioned preparation method. Electrochemical testing of the negative electrode sheet prepared in this embodiment of the present invention demonstrated excellent sodium storage performance.

[0055] In some embodiments of the present invention, the conductive agent is selected from acetylene black, conductive carbon black, and graphite, but is not limited thereto. Any conductive agent commonly used in the art can be used to improve the conductivity of electrons generated in the electrode and thus improve battery performance.

[0056] In some embodiments of the present invention, the binder is selected from styrene-butadiene rubber (SBR) emulsion, carboxymethyl cellulose (CMC), polyethylene oxide (PEO), polypropylene oxide (PPO), polyvinylidene fluoride (PVDF), polyvinylidene fluoride-hexafluoropropylene copolymer (PVDF-HFP), polyacrylonitrile (PAN), polymethyl acrylate (PMA), polymethyl methacrylate (PMMA), but is not limited thereto. Commonly used negative electrode material binders in the art can be used, and PVDF is usually used.

[0057] In some embodiments of the present invention, the current collector is an inactive conductive current collector, which can be selected from copper foil (mesh), titanium foil (mesh), iron foil (mesh), nickel foil (mesh), carbon cloth, conductive nylon, etc., but is not limited thereto.

[0058] In a fifth aspect of the present invention, a battery is provided, comprising the negative electrode plate as described above.

[0059] In some embodiments of the present invention, the battery comprises a half-cell or a full-cell, but is not limited thereto. The negative electrode plate provided by the present invention can also be used in energy storage devices such as supercapacitors and hybrid supercapacitors. The positive electrode active materials, separators, and electrolytes used in the assembled battery are not limited in any way; commonly used materials in the art can be used and are not further elaborated here.

[0060] In some embodiments of the invention, the battery comprises a sodium ion battery.

[0061] The present invention uses the above-mentioned hard carbon material as the negative electrode active material of the sodium ion battery to prepare the negative electrode plate, and the metallic sodium plate is used as the reference electrode and the counter electrode, which is assembled with the electrolyte into a sodium ion half-cell. Electrochemical testing is carried out, and the battery has excellent sodium storage performance.

[0062] Preferably, the method for preparing the sodium ion half-cell comprises the steps of:

[0063] S100: Preparation of hard carbon negative electrode sheet: The hard carbon active material, conductive agent, and binder are weighed in a certain proportion, added to an appropriate solvent, and thoroughly mixed into a uniform slurry to form a negative electrode active material layer; the negative electrode current collector is cleaned, and the negative electrode active material layer is evenly coated on the surface of the negative electrode current collector, followed by vacuum drying. After the negative electrode active material layer is completely dry, it is cut to obtain a negative electrode sheet of the desired size. Preferably, the selected binder is conductive carbon black, the binder is styrene-butadiene rubber (SBR) emulsion and carboxymethyl cellulose (CMC), and the current collector is copper foil; the vacuum drying temperature is preferably 60°C.

[0064] S200: Prepare sodium metal electrode: Cut the sodium metal foil into discs and place them in a glove box for later use. Preferably, the thickness is 0.5 mm and the diameter of the discs is 14 mm.

[0065] S300: Electrolyte Preparation: Weigh an appropriate amount of sodium salt and dissolve it in a solvent, stirring thoroughly to prepare the sodium-ion storage battery electrolyte. All operations are performed in an argon glove box (water and oxygen content is less than 0.1 ppm). Preferably, the sodium salt is sodium hexafluorophosphate (NaPF6), and the solvent is a mixed solution of ethylene carbonate (EC), dimethyl carbonate (DMC), and ethyl methyl carbonate (EMC) (1:1:1, v:v:v).

[0066] S400: Assembling the sodium-ion half-cell: Assemble the negative electrode shell, sodium metal electrode, separator, hard carbon negative electrode sheet, gasket, spring, and positive electrode shell in sequence. After assembly, press and seal the battery and store it at room temperature. A PP separator is preferred.

[0067] It should be noted that although the above steps S100-S400 describe the operations of the preparation method in a specific order, this does not require or imply that these operations must be performed in this specific order. The preparations in steps S100-S300 can be performed simultaneously or in any order. BRIEF DESCRIPTION OF THE DRAWINGS

[0068] The present invention will be further described below with reference to the accompanying drawings and embodiments, in which:

[0069] FIG1 is a schematic diagram of a dielectric barrier discharge plasma (DBD) assisted rapid sintering mass production device according to an embodiment of the present invention;

[0070] FIG2 is a transmission electron micrograph of a hard carbon material prepared in an embodiment of the present invention;

[0071] FIG3 is a schematic diagram of a typical charge and discharge curve of the hard carbon material prepared in an embodiment of the present invention used as a sodium ion half-cell. DETAILED DESCRIPTION

[0072] The following will clearly and completely describe the concept and technical effects of the present invention in conjunction with the embodiments to fully understand the purpose, features and effects of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, other embodiments obtained by those skilled in the art without creative work are all within the scope of protection of the present invention.

[0073] In the description of the present invention, reference to terms such as "one embodiment," "some embodiments," "illustrative embodiments," "examples," "specific examples," or "some examples" means that the specific features, structures, materials, or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the exemplary expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

[0074] In the description of the present invention, unless otherwise indicated, the numerical range "a-b" is an abbreviation for any combination of real numbers between a and b, where a and b are real numbers. Unless otherwise indicated, the individual reactions or steps may or may not be performed sequentially. Preferably, the reaction methods of the present invention are performed sequentially.

[0075] If no specific techniques or conditions are specified in the following examples, the methods were carried out according to the techniques or conditions described in the literature in the field or according to the product instructions. All reagents or instruments without manufacturer specified are commercially available conventional products.

[0076] Example 1:

[0077] Preparation and application of hard carbon materials:

[0078] (1) The starch is placed in a tube furnace and dried by heat treatment in air at 160°C;

[0079] (2) Then, the preheated material was pretreated at 500°C for 2 hours in an argon atmosphere, cooled naturally to room temperature, and then ground and pulverized to obtain a black powder, thereby completing the pre-carbonization of the carbon source material;

[0080] (3) The pre-carbonized powder material is placed in a dielectric barrier discharge plasma (DBD) assisted sintering device (using a power density of 3kW / m 2 , the distance between the upper and lower insulating heat conducting plates is 5mm), the temperature is raised to 1250℃ at 200℃ / min, the sintering time is maintained for 25 minutes, and the conveying speed is 0.02rpm;

[0081] (4) The carbonized material is naturally cooled to room temperature, taken out and ground, and then screened to obtain a starch-derived hard carbon material.

[0082] (5) Using the above-mentioned hard carbon material as the active material, a hard carbon negative electrode sheet was prepared, and 1M NaPF6 EC:DMC:EMC (1:1:1, v:v:v) was used as the electrolyte to assemble a sodium ion half-cell, and the half-cell was tested using a battery testing system.

[0083] Example 2:

[0084] Preparation and application of hard carbon materials:

[0085] (1) placing sucrose in a tube furnace, heat-treating and drying it in air at 160°C, and then crushing it into a powder material;

[0086] (2) Then, the preheated material was pretreated at 500°C for 2 hours in an argon atmosphere, cooled naturally to room temperature, and then ground and pulverized to obtain a black powder, thereby completing the pre-carbonization of the carbon source material;

[0087] (3) The pre-carbonized powder material is placed in a dielectric barrier discharge plasma (DBD) assisted sintering device (using a power density of 3kW / m 2 , the distance between the upper and lower insulating heat conducting plates is 5mm), the temperature is raised to 1250℃ at 200℃ / min, the sintering time is maintained for 25 minutes, and the conveying speed is 0.02rpm;

[0088] (4) The carbonized material is naturally cooled to room temperature, taken out and ground, and then screened to obtain a starch-derived hard carbon material.

[0089] (5) Using the above-mentioned hard carbon material as the active material, a hard carbon negative electrode sheet was prepared, and 1M NaPF6 EC:DMC:EMC (1:1:1, v:v:v) was used as the electrolyte to assemble a sodium ion half-cell, and the half-cell was tested using a battery testing system.

[0090] Example 3:

[0091] Preparation and application of hard carbon materials:

[0092] (1) Anthracite is placed in a tube furnace, heat-treated and dried in air at 160°C, and then crushed to form a powder material;

[0093] (2) Place the anthracite powder material in a dielectric barrier discharge plasma (DBD) assisted sintering device (using a power density of 3kW / m 2 , the distance between the upper and lower insulating heat conducting plates is 5mm), the temperature is raised to 1250℃ at 200℃ / min, the sintering time is maintained for 25 minutes, and the conveying speed is 0.02rpm;

[0094] (3) The carbonized material is naturally cooled to room temperature, taken out and ground, and then screened to obtain a starch-derived hard carbon material.

[0095] (4) Using the above-mentioned hard carbon material as the active material, a hard carbon negative electrode sheet was prepared, and 1M NaPF6 EC:DMC:EMC (1:1:1, v:v:v) was used as the electrolyte to assemble a sodium ion half-cell, and the half-cell was tested using a battery testing system.

[0096] Example 4:

[0097] Preparation and application of hard carbon materials:

[0098] (1) Starch is placed in a tube furnace, heat-treated and dried in air at 160°C, and then crushed to form a powder material;

[0099] (2) Then, the preheated material was pretreated at 500°C for 2 hours in an argon atmosphere, cooled naturally to room temperature, and then ground and pulverized to obtain a black powder, thereby completing the pre-carbonization of the carbon source material;

[0100] (3) The pre-carbonized powder material is placed in a dielectric barrier discharge plasma (DBD) assisted sintering device (using a power density of 3kW / m 2 , the distance between the upper and lower insulating heat conducting plates is 5mm), the temperature is raised to 1100℃ at 200℃ / min, the sintering time is maintained for 25 minutes, and the conveying speed is 0.02rpm;

[0101] (4) The carbonized material is naturally cooled to room temperature, taken out and ground, and then screened to obtain a starch-derived hard carbon material.

[0102] (5) Using the above-mentioned hard carbon material as the active material, a hard carbon negative electrode sheet was prepared, and 1M NaPF6 EC:DMC:EMC (1:1:1, v:v:v) was used as the electrolyte to assemble a sodium ion half-cell, and the half-cell was tested using a battery testing system.

[0103] Example 5:

[0104] Preparation and application of hard carbon materials:

[0105] (1) The starch is placed in a tube furnace and dried by heat treatment in air at 160°C;

[0106] (2) Then, the preheated material was pretreated at 500°C for 2 hours in an argon atmosphere, cooled naturally to room temperature, and then ground and pulverized to obtain a black powder, thereby completing the pre-carbonization of the carbon source material;

[0107] (3) The pre-carbonized powder material is placed in a dielectric barrier discharge plasma (DBD) assisted sintering device (using a power density of 3kW / m 2 , the distance between the upper and lower insulating heat conducting plates is 5mm), the temperature is raised to 1400℃ at 200℃ / min, the sintering time is maintained for 25 minutes, and the conveying speed is 0.02rpm;

[0108] (4) The carbonized material is naturally cooled to room temperature, taken out and ground, and then screened to obtain a starch-derived hard carbon material.

[0109] (5) Using the above-mentioned hard carbon material as the active material, a hard carbon negative electrode sheet was prepared, and 1M NaPF6 EC:DMC:EMC (1:1:1, v:v:v) was used as the electrolyte to assemble a sodium ion half-cell, and the half-cell was tested using a battery testing system.

[0110] Example 6:

[0111] Preparation and application of hard carbon materials:

[0112] (1) The starch is placed in a tube furnace and dried by heat treatment in air at 160°C;

[0113] (2) Then, the preheated material was pretreated at 500°C for 2 hours in an argon atmosphere, cooled naturally to room temperature, and then ground and pulverized to obtain a black powder, thereby completing the pre-carbonization of the carbon source material;

[0114] (3) The pre-carbonized powder material is placed in a dielectric barrier discharge plasma (DBD) assisted sintering device (using a power density of 3kW / m 2 , the distance between the upper and lower insulating heat conducting plates is 5mm), the temperature is raised to 1250℃ at 300℃ / min, the sintering time is maintained for 25 minutes, and the conveying speed is 0.02rpm;

[0115] (4) The carbonized material is naturally cooled to room temperature, taken out and ground, and then screened to obtain a starch-derived hard carbon material.

[0116] (5) Using the above-mentioned hard carbon material as the active material, a hard carbon negative electrode sheet was prepared, and 1M NaPF6 EC:DMC:EMC (1:1:1, v:v:v) was used as the electrolyte to assemble a sodium ion half-cell, and the half-cell was tested using a battery testing system.

[0117] Example 7:

[0118] Preparation and application of hard carbon materials:

[0119] (1) The starch is placed in a tube furnace and dried by heat treatment in air at 160°C;

[0120] (2) Then, the preheated material was pretreated at 500°C for 2 hours in an argon atmosphere, cooled naturally to room temperature, and then ground and pulverized to obtain a black powder, thereby completing the pre-carbonization of the carbon source material;

[0121] (3) The pre-carbonized powder material is placed in a dielectric barrier discharge plasma (DBD) assisted sintering device (using a power density of 3kW / m 2 , the distance between the upper and lower insulating heat conducting plates is 5mm), the temperature is raised to 1250℃ at 400℃ / min, the sintering time is maintained for 25 minutes, and the conveying speed is 0.02rpm;

[0122] (4) The carbonized material is naturally cooled to room temperature, taken out and ground, and then screened to obtain a starch-derived hard carbon material.

[0123] (5) Using the above-mentioned hard carbon material as the active material, a hard carbon negative electrode sheet was prepared, and 1M NaPF6 EC:DMC:EMC (1:1:1, v:v:v) was used as the electrolyte to assemble a sodium ion half-cell, and the half-cell was tested using a battery testing system.

[0124] Example 8:

[0125] Preparation and application of hard carbon materials:

[0126] (1) The starch is placed in a tube furnace and dried by heat treatment in air at 160°C;

[0127] (2) Then, the preheated material was pretreated at 500°C for 2 hours in an argon atmosphere, cooled naturally to room temperature, and then ground and pulverized to obtain a black powder, thereby completing the pre-carbonization of the carbon source material;

[0128] (3) The pre-carbonized powder material is placed in a dielectric barrier discharge plasma (DBD) assisted sintering device (using a power density of 3kW / m 2 , the distance between the upper and lower insulating heat conducting plates is 5mm), the temperature is raised to 1250℃ at 200℃ / min, the sintering time is maintained for 10 minutes, and the conveying speed is 0.05rpm;

[0129] (4) The carbonized material is naturally cooled to room temperature, taken out and ground, and then screened to obtain a starch-derived hard carbon material.

[0130] (5) Using the above-mentioned hard carbon material as the active material, a hard carbon negative electrode sheet was prepared, and 1M NaPF6 EC:DMC:EMC (1:1:1, v:v:v) was used as the electrolyte to assemble a sodium ion half-cell, and the half-cell was tested using a battery testing system.

[0131] Example 9:

[0132] Preparation and application of hard carbon materials:

[0133] (1) The starch is placed in a tube furnace and dried by heat treatment in air at 160°C;

[0134] (2) Then, the preheated material was pretreated at 500°C for 2 hours in an argon atmosphere, cooled naturally to room temperature, and then ground and pulverized to obtain a black powder, thereby completing the pre-carbonization of the carbon source material;

[0135] (3) The pre-carbonized powder material is placed in a dielectric barrier discharge plasma (DBD) assisted sintering device (using a power density of 3kW / m 2 , the distance between the upper and lower insulating heat conducting plates is 5mm), the temperature is raised to 1250℃ at 200℃ / min, the sintering time is maintained for 5 minutes, and the conveying speed is 0.1rpm;

[0136] (4) The carbonized material is naturally cooled to room temperature, taken out and ground, and then screened to obtain a starch-derived hard carbon material.

[0137] (5) Using the above-mentioned hard carbon material as the active material, a hard carbon negative electrode sheet was prepared, and 1M NaPF6 EC:DMC:EMC (1:1:1, v:v:v) was used as the electrolyte to assemble a sodium ion half-cell, and the half-cell was tested using a battery testing system.

[0138] Example 10:

[0139] Preparation and application of hard carbon materials:

[0140] (1) The starch and anthracite mixture is placed in a tube furnace and dried by heat treatment in air at 160°C;

[0141] (2) Then, the preheated material was pretreated at 500°C for 2 hours in an argon atmosphere, cooled naturally to room temperature, and then ground and pulverized to obtain a black powder, thereby completing the pre-carbonization of the carbon source material;

[0142] (3) The pre-carbonized powder material is placed in a dielectric barrier discharge plasma (DBD) assisted sintering device (using a power density of 3kW / m 2 , the distance between the upper and lower insulating heat conducting plates is 5mm), the temperature is raised to 1250℃ at 200℃ / min, the sintering time is maintained for 25 minutes, and the conveying speed is 0.02rpm;

[0143] (4) The carbonized material is naturally cooled to room temperature, taken out and ground, and then screened to obtain a starch-derived hard carbon material.

[0144] (5) Using the above-mentioned hard carbon material as the active material, a hard carbon negative electrode sheet was prepared, and 1M NaPF6 EC:DMC:EMC (1:1:1, v:v:v) was used as the electrolyte to assemble a sodium ion half-cell, and the half-cell was tested using a battery testing system.

[0145] Example 11:

[0146] Preparation and application of hard carbon materials:

[0147] (1) The starch is placed in a tube furnace and dried by heat treatment in air at 160°C;

[0148] (2) Then, the preheated material was pretreated at 500°C for 2 hours in an argon atmosphere, cooled naturally to room temperature, and then ground and pulverized to obtain a black powder, thereby completing the pre-carbonization of the carbon source material;

[0149] (3) The pre-carbonized powder material is placed in a dielectric barrier discharge plasma (DBD) assisted sintering device (using a power density of 5kW / m 2 , the distance between the upper and lower insulating heat conducting plates is 5mm), the temperature is raised to 1250℃ at 200℃ / min, the sintering time is maintained for 25 minutes, and the conveying speed is 0.02rpm;

[0150] (4) The carbonized material is naturally cooled to room temperature, taken out and ground, and then screened to obtain a starch-derived hard carbon material.

[0151] (5) Using the above-mentioned hard carbon material as the active material, a hard carbon negative electrode sheet was prepared, and 1M NaPF6 EC:DMC:EMC (1:1:1, v:v:v) was used as the electrolyte to assemble a sodium ion half-cell, and the half-cell was tested using a battery testing system.

[0152] Example 12:

[0153] Preparation and application of hard carbon materials:

[0154] (1) The starch is placed in a tube furnace and dried by heat treatment in air at 160°C;

[0155] (2) Then, the preheated material was pretreated at 500°C for 2 hours in an argon atmosphere, cooled naturally to room temperature, and then ground and pulverized to obtain a black powder, thereby completing the pre-carbonization of the carbon source material;

[0156] (3) The pre-carbonized powder material is placed in a dielectric barrier discharge plasma (DBD) assisted sintering device (using a power density of 3kW / m 2 , the distance between the upper and lower insulating heat conducting plates is 3mm), the temperature is raised to 1250℃ at 200℃ / min, the sintering time is maintained for 25 minutes, and the conveying speed is 0.02rpm;

[0157] (4) The carbonized material is naturally cooled to room temperature, taken out and ground, and then screened to obtain a starch-derived hard carbon material.

[0158] (5) Using the above-mentioned hard carbon material as the active material, a hard carbon negative electrode sheet was prepared, and 1M NaPF6 EC:DMC:EMC (1:1:1, v:v:v) was used as the electrolyte to assemble a sodium ion half-cell, and the half-cell was tested using a battery testing system.

[0159] Example 13:

[0160] Preparation and application of hard carbon materials:

[0161] (1) Place the bamboo in a tubular furnace and heat-dry it in air at 160°C;

[0162] (2) Then, the preheated material was pretreated at 500°C for 2 hours in an argon atmosphere, cooled naturally to room temperature, and then ground and pulverized to obtain a black powder, thereby completing the pre-carbonization of the carbon source material;

[0163] (3) The pre-carbonized powder material is placed in a dielectric barrier discharge plasma (DBD) assisted sintering device (using a power density of 3kW / m 2, the distance between the upper and lower insulating heat conducting plates is 3mm), the temperature is raised to 1250℃ at 200℃ / min, the sintering time is maintained for 25 minutes, and the conveying speed is 0.02rpm;

[0164] (4) The carbonized material is naturally cooled to room temperature, taken out and ground, and then screened to obtain a starch-derived hard carbon material.

[0165] (5) Using the above-mentioned hard carbon material as the active material, a hard carbon negative electrode sheet was prepared, and 1M NaPF6 EC:DMC:EMC (1:1:1, v:v:v) was used as the electrolyte to assemble a sodium ion half-cell, and the half-cell was tested using a battery testing system.

[0166] Example 14:

[0167] Preparation and application of hard carbon materials:

[0168] (1) Coconut shells were placed in a tube furnace and dried by heat treatment in air at 160°C;

[0169] (2) Then, the preheated material was pretreated at 500°C for 2 hours in an argon atmosphere, cooled naturally to room temperature, and then ground and pulverized to obtain a black powder, thereby completing the pre-carbonization of the carbon source material;

[0170] (3) The pre-carbonized powder material is placed in a dielectric barrier discharge plasma (DBD) assisted sintering device (using a power density of 3kW / m 2 , the distance between the upper and lower insulating heat conducting plates is 3mm), the temperature is raised to 1250℃ at 200℃ / min, the sintering time is maintained for 25 minutes, and the conveying speed is 0.02rpm;

[0171] (4) The carbonized material is naturally cooled to room temperature, taken out and ground, and then screened to obtain a starch-derived hard carbon material.

[0172] (5) Using the above-mentioned hard carbon material as the active material, a hard carbon negative electrode sheet was prepared, and 1M NaPF6 EC:DMC:EMC (1:1:1, v:v:v) was used as the electrolyte to assemble a sodium ion half-cell, and the half-cell was tested using a battery testing system.

[0173] Example 15:

[0174] Preparation and application of hard carbon materials:

[0175] (1) The walnut shells were placed in a tube furnace and dried by heat treatment in air at 160°C;

[0176] (2) Then, the preheated material was pretreated at 500°C for 2 hours in an argon atmosphere, cooled naturally to room temperature, and then ground and pulverized to obtain a black powder, thereby completing the pre-carbonization of the carbon source material;

[0177] (3) The pre-carbonized powder material is placed in a dielectric barrier discharge plasma (DBD) assisted sintering device (using a power density of 3kW / m 2 , the distance between the upper and lower insulating heat conducting plates is 3mm), the temperature is raised to 1250℃ at 200℃ / min, the sintering time is maintained for 25 minutes, and the conveying speed is 0.02rpm;

[0178] (4) The carbonized material is naturally cooled to room temperature, taken out and ground, and then screened to obtain a starch-derived hard carbon material.

[0179] (5) Using the above-mentioned hard carbon material as the active material, a hard carbon negative electrode sheet was prepared, and 1M NaPF6 EC:DMC:EMC (1:1:1, v:v:v) was used as the electrolyte to assemble a sodium ion half-cell, and the half-cell was tested using a battery testing system.

[0180] Example 16:

[0181] Preparation and application of hard carbon materials:

[0182] (1) Phenolic resin is placed in a tube furnace and dried by heat treatment in air at 160°C;

[0183] (2) Then, the preheated material was pretreated at 500°C for 2 hours in an argon atmosphere, cooled naturally to room temperature, and then ground and pulverized to obtain a black powder, thereby completing the pre-carbonization of the carbon source material;

[0184] (3) The pre-carbonized powder material is placed in a dielectric barrier discharge plasma (DBD) assisted sintering device (using a power density of 3kW / m 2 , the distance between the upper and lower insulating heat conducting plates is 3mm), the temperature is raised to 1250℃ at 200℃ / min, the sintering time is maintained for 25 minutes, and the conveying speed is 0.02rpm;

[0185] (4) The carbonized material is naturally cooled to room temperature, taken out and ground, and then screened to obtain a starch-derived hard carbon material.

[0186] (5) Using the above-mentioned hard carbon material as the active material, a hard carbon negative electrode sheet was prepared, and 1M NaPF6 EC:DMC:EMC (1:1:1, v:v:v) was used as the electrolyte to assemble a sodium ion half-cell, and the half-cell was tested using a battery testing system.

[0187] Example 17:

[0188] Preparation and application of hard carbon materials:

[0189] (1) Place polyacrylonitrile in a tube furnace and heat-dry it in air at 160°C;

[0190] (2) Then, the preheated material was pretreated at 500°C for 2 hours in an argon atmosphere, cooled naturally to room temperature, and then ground and pulverized to obtain a black powder, thereby completing the pre-carbonization of the carbon source material;

[0191] (3) The pre-carbonized powder material is placed in a dielectric barrier discharge plasma (DBD) assisted sintering device (using a power density of 3kW / m 2 , the distance between the upper and lower insulating heat conducting plates is 3mm), the temperature is raised to 1250℃ at 200℃ / min, the sintering time is maintained for 25 minutes, and the conveying speed is 0.02rpm;

[0192] (4) The carbonized material is naturally cooled to room temperature, taken out and ground, and then screened to obtain a starch-derived hard carbon material.

[0193] (5) Using the above-mentioned hard carbon material as the active material, a hard carbon negative electrode sheet was prepared, and 1M NaPF6 EC:DMC:EMC (1:1:1, v:v:v) was used as the electrolyte to assemble a sodium ion half-cell, and the half-cell was tested using a battery testing system.

[0194] Example 18:

[0195] Preparation and application of hard carbon materials:

[0196] (1) Pomelo peels were placed in a tube furnace and dried by heat treatment at 160°C in air;

[0197] (2) Then, the preheated material was pretreated at 500°C for 2 hours in an argon atmosphere, cooled naturally to room temperature, and then ground and pulverized to obtain a black powder, thereby completing the pre-carbonization of the carbon source material;

[0198] (3) The pre-carbonized powder material is placed in a dielectric barrier discharge plasma (DBD) assisted sintering device (using a power density of 3kW / m 2 , the distance between the upper and lower insulating heat conducting plates is 3mm), the temperature is raised to 1250℃ at 200℃ / min, the sintering time is maintained for 25 minutes, and the conveying speed is 0.02rpm;

[0199] (4) The carbonized material is naturally cooled to room temperature, taken out and ground, and then screened to obtain a starch-derived hard carbon material.

[0200] (5) Using the above-mentioned hard carbon material as the active material, a hard carbon negative electrode sheet was prepared, and 1M NaPF6 EC:DMC:EMC (1:1:1, v:v:v) was used as the electrolyte to assemble a sodium ion half-cell, and the half-cell was tested using a battery testing system.

[0201] The electrochemical properties of the carbon components of the materials and half-cells prepared in Examples 1-18 were tested (including specific capacity, initial efficiency, capacity retention, etc., with reference to conventional testing methods in the art), and the results are shown in Table 1.

[0202] Table 1

[0203] As can be seen from the above table, the desired hard carbon material can be obtained based on the preparation method of the present invention, and the carbon content can be effectively controlled by regulating key parameters, and the electrochemical properties of the obtained hard carbon material can be optimized.

[0204] The above-described embodiments merely illustrate several implementations of the present invention. While the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that a person skilled in the art would be able to make numerous variations and improvements without departing from the spirit of the present invention, and all such variations and improvements fall within the scope of protection of the present invention.

Claims

1. A preparation method of a hard carbon negative electrode material, characterized in that, Comprising the steps of: Providing a carbon source material, drying the carbon source material, and obtaining a powdered material after ball milling and pulverization; Performing pre-carbonization treatment on the powdered material in an inert gas atmosphere, and obtaining a precursor powder after grinding and pulverization; Under normal pressure conditions, feeding the precursor powder into a dielectric barrier discharge plasma-assisted sintering device by a roll-to-roll process, and performing carbonization treatment on the precursor powder to obtain a carbonized material; Taking out the carbonized material, and obtaining the hard carbon negative electrode material after grinding and pulverization.

2. The preparation method of the hard carbon negative electrode material according to claim 1, characterized in that, The carbon source material is selected from one or more mixtures of minerals, biomass, and chemical products.

3. The preparation method of the hard carbon negative electrode material according to claim 1, characterized in that, The temperature of the drying treatment is 50-200°C, preferably 150-200°C; and / or, the time of the drying treatment is 1-10 hours, preferably 1-2 hours.

4. The preparation method of the hard carbon negative electrode material according to claim 1, characterized in that, The temperature of the pre-carbonization treatment is 500-800°C, preferably 500-550°C; and / or, the time of the pre-carbonization treatment is 1-10 hours, preferably 2-3 hours.

5. The preparation method of the hard carbon negative electrode material according to claim 1, characterized in that, The power density of the dielectric barrier discharge plasma-assisted sintering device is 1 to 10 kW / m 2 , preferably 3 to 5 kW / m 2 ; and / or, the distance between the dielectric resistance baffles of the dielectric barrier discharge plasma-assisted sintering device is 1 to 20 mm, preferably 3 to 8 mm.

6. The preparation method of the hard carbon negative electrode material according to claim 1, characterized in that, The conditions for the carbonization treatment are an inert gas atmosphere; and / or, the temperature rise rate is 100-1000°C / minute, preferably 200-500°C / minute; and / or, the sintering temperature is 800-1500°C, preferably 1000-1300°C; and / or, the sintering time is 20 seconds to 30 minutes, preferably 10-25 minutes.

7. A hard carbon negative electrode material, characterized in that, The hard carbon negative electrode material is prepared by the preparation method of the hard carbon negative electrode material according to any one of claims 1-6.

8. Application of a preparation method of a hard carbon negative electrode material according to any one of claims 1-6 in the preparation of a battery negative electrode material.

9. A negative electrode plate, characterized in that, Comprising the hard carbon negative electrode material according to claim 7.

10. A battery, characterized in that, Comprising the negative electrode plate according to claim 9.

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