Preparation method and application of hard carbon negative electrode material, negative electrode plate and battery

Abstract

The invention discloses a preparation method and application of a hard carbon negative electrode material, a negative electrode plate and a battery, and provides a method for rapidly preparing the hard carbon material in a large scale by combining a dielectric barrier discharge plasma (DBD) assisted sintering technology with transmission. According to the preparation method, the temperature rise rate is high (100-1000 DEG C / min), the sintering time is short (20 seconds to 30 minutes), the energy consumption is low, the production efficiency of the hard carbon negative electrode material is improved, the energy consumption and the cost are reduced, and controllable adjustment of the microstructure of the material is realized; and on the other hand, the method can be used for preparing under normal pressure, and a roll-to-roll conveying process is combined, so that the hard carbon negative electrode material can be rapidly and macroscopically prepared, and the efficiency of the preparation process is further improved. Moreover, the carbon source material is wide in source, the microstructure and doping characteristics of the hard carbon negative electrode material can be effectively regulated and controlled, and finally, rapid macro preparation of the hard carbon negative electrode material is realized. When the hard carbon material is used as a sodium ion battery negative electrode material, excellent sodium storage performance can be shown.

Description

Technical Field

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

[0002] Lithium-ion batteries are widely used in the fields of 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 restricted. Relatively speaking, sodium resources are rich and low-cost, and sodium and lithium are elements of the same group, with similar electrochemical properties. Therefore, sodium-ion batteries are considered to be one of the next-generation battery technologies with great application potential. Especially, they show significant cost advantages in the field of large-scale energy storage and have also received extensive attention. In sodium-ion batteries, due to sodium ions having a significantly larger ionic radius than lithium ions and having a solvation structure different from that of lithium ions, this also limits the selection range of negative electrode materials for sodium-ion batteries. Hard carbon materials are considered to be the most promising negative electrode materials for sodium-ion batteries due to their rich raw material sources and stable structures.

[0003] In related technologies, hard carbon materials usually need to be prepared by high-temperature carbonization processes. However, the common tube furnace equipment generally has deficiencies such as slow heating rate, long sintering time, and high energy consumption in the process of preparing hard carbon negative electrode materials, which reduces the production efficiency of hard carbon negative electrodes and increases the production cost. For the method of preparing hard carbon negative electrode materials by using rapid calcination carbonization technology, although the temperature rise rate and sintering time can meet the requirements, the above carbonization process needs to be carried out under high-pressure conditions (20-50 MPa) and cannot achieve large-scale mass preparation.

[0004] Therefore, solving the deficiencies such as slow heating rate, long sintering time, and high energy consumption in the process of preparing hard carbon negative electrode materials, and developing a carbonization technology that can achieve large-scale mass preparation and has both low cost and high efficiency is of great significance for realizing the large-scale application of hard carbon negative electrodes in sodium-ion batteries. Summary of the Invention

[0005] The present invention aims to solve at least one of the technical problems existing in the prior art. For this purpose, the present invention provides a preparation method and application of a hard carbon negative electrode material, a negative electrode sheet and a battery, aiming to solve the problems such as slow heating rate, long sintering time, and high energy consumption existing in the current large-scale mass preparation of hard carbon negative electrode materials.

[0006] In the first aspect of the present invention, a preparation method of a hard carbon negative electrode material is provided, including the steps of:

[0007] S1. Provide a carbon source material, perform a drying treatment on the carbon source material, and obtain a powdery material after ball milling and pulverization;

[0008] S2. Precarbonize the powdery material in an inert gas atmosphere, grind and crush it to obtain a precursor powder;

[0009] S3. Under atmospheric pressure conditions, use a roll-to-roll process to feed the precursor powder into a dielectric barrier discharge plasma-assisted sintering device, and carbonize the precursor powder to obtain a carbonized material;

[0010] S4. Take out the carbonized material, grind and crush it to obtain the hard carbon negative electrode material.

[0011] The method for preparing a hard carbon negative electrode material according to the embodiments of the present invention has at least the following beneficial effects: The present invention proposes a method for rapidly sintering a large amount of hard carbon negative electrode materials assisted by dielectric barrier discharge plasma (DBD). 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 microstructure of the materials; on the other hand, combined with the conveying process, it can rapidly prepare a large amount of hard carbon negative electrode materials, further improving the efficiency of the preparation process. The transmission rapid carbonization technology of the present invention has a fast temperature rise rate, a short sintering time, and low energy consumption; and it does not need to be carried out under high-pressure conditions, can be prepared under atmospheric pressure conditions, and combined with the conveying process can realize the large-scale preparation and production of hard carbon negative electrode materials, improving the production efficiency and reducing the cost; moreover, the microstructure and doping characteristics of the hard carbon negative electrode materials can be adjusted according to DBD discharge parameters, temperature rise rate, sintering time, conveying speed, etc. Finally, the transmission rapid carbonization method provided by the present invention, which combines low cost and high efficiency, can prepare a large amount of hard carbon negative electrode materials, which is of great significance for realizing the large-scale application of hard carbon negative electrodes for sodium ion batteries. Using the prepared hard carbon material as the negative electrode material for sodium ion batteries and matching the positive electrode material and electrolyte can exhibit excellent sodium storage performance.

[0012] Figure 1 The figure shows a schematic diagram of a device for rapidly sintering a large amount of hard carbon assisted by dielectric barrier discharge plasma (DBD) proposed by the present invention. As shown in the figure, the DBD system generates plasma between dielectric barriers, and at the same time uses a heating sheet to heat the entire plasma region, and at the same time transports the raw materials and the prepared hard carbon materials through a winding and conveying device, so as to realize the rapid sintering of DBD-assisted large-scale preparation of hard carbon materials.

[0013] In some embodiments of the present invention, the carbon source material is selected from one or more mixtures of minerals, biomass, and chemical products.

[0014] In some preferred embodiments of the present invention, the carbon source material is selected from one or more mixtures of anthracite, sucrose, starch, straw, resin, asphalt, coke, wood, bamboo, and coconut shell.

[0015] The raw materials used in the present invention are widely sourced. Mineral substances, biomass, and chemical products can be utilized as carbon sources, including but not limited to at least one or a mixture of multiple coal-based or biomass-based materials such as anthracite, sucrose, starch, straw, resin, asphalt, coke, wood, bamboo, coconut shell, etc.

[0016] Preferably, the carbon source material is selected from starch.

[0017] Preferably, the carbon source material is selected from anthracite. When anthracite is selected alone as the carbon source material, pre-carbonization treatment may not be necessary.

[0018] In some embodiments of the present invention, in step S1, before drying the carbon source material, a step of impurity removal is further included.

[0019] In some embodiments of the present invention, the temperature of the drying treatment is 50 - 200 °C.

[0020] In some preferred embodiments of the present invention, the temperature of the drying treatment is 150 - 200 °C.

[0021] In some embodiments of the present invention, the time of the drying treatment is 1 - 10 hours.

[0022] In some preferred embodiments of the present invention, the time of the drying treatment is 1 - 2 hours.

[0023] In some embodiments of the present invention, in step S2, the inert atmosphere is argon.

[0024] In some embodiments of the present invention, the temperature of the pre-carbonization treatment is 500 - 800 °C.

[0025] In some preferred embodiments of the present invention, the temperature of the pre-carbonization treatment is 500 - 550 °C.

[0026] More preferably, the temperature of the pre-carbonization treatment is about 500 °C.

[0027] In some embodiments of the present invention, the time of the pre-carbonization treatment is 1 - 10 hours.

[0028] In some preferred embodiments of the present invention, the time of the pre-carbonization treatment is 2 - 3 hours.

[0029] In the present invention, the powdery 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, thus completing the pre-carbonization of the carbon source material.

[0030] In some embodiments of the present invention, in step S3, under atmospheric pressure conditions, the pre-carbonized black precursor powder is placed in a dielectric barrier discharge plasma (DBD) assisted sintering device, and combined with a roll-to-roll process, high-temperature rapid carbonization is carried out. The atmosphere inside the device is an inert gas (such as argon), the temperature rise rate is 100 - 1000 °C / minute, the sintering temperature is 800 - 1500 °C, and the sintering time is 20 seconds - 30 minutes.

[0031] The 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 controllably adjusted according to actual needs, and it is widely used in fields such as material surface treatment, thin film material deposition, and coal combustion assistance. In the process of preparing hard carbon, it is often necessary to overcome carbon-oxygen, carbon-carbon, and carbon-hydrogen chemical bonds with high bond energies in the carbon source material, which requires a high temperature in the sintering process and high energy consumption. The present invention prepares hard carbon materials by introducing dielectric barrier discharge plasma technology to assist sintering. By using the interaction between high-energy particles in the plasma and active groups in the carbon source material, it affects the chemical equilibrium in the carbonization process, regulates the carbonization process, reduces the carbonization temperature, accelerates the hard carbon preparation process, and reduces energy consumption. At the same time, the present invention uses the roll-to-roll process to send the precursor powder into the dielectric barrier discharge plasma assisted sintering device to carbonize the precursor powder to obtain a carbonized material; the winding speed of the roll-to-roll process is determined according to the required sintering time and the scale of the plasma region, thereby effectively controlling the sintering time in the process of preparing the hard carbon negative electrode, further improving the production efficiency and reducing costs.

[0032] 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 。

[0033] 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 。

[0034] In some embodiments of the present invention, the distance between the dielectric barrier plates of the dielectric barrier discharge plasma (DBD) assisted sintering device is 1 - 20 mm.

[0035] 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 - 8 mm.

[0036] In some embodiments of the present invention, the temperature rise rate of the dielectric barrier discharge plasma (DBD) assisted sintering device is 100 - 1000 °C / minute.

[0037] 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 / minute.

[0038] In some embodiments of the present invention, the conditions for the carbonization treatment are an inert gas atmosphere, preferably an argon atmosphere.

[0039] In some embodiments of the present invention, the temperature rise rate of the carbonization treatment is 100 - 1000 °C / minute.

[0040] In some preferred embodiments of the present invention, the temperature rise rate of the carbonization treatment is 200 - 500 °C / minute.

[0041] In some embodiments of the present invention, the sintering temperature of the carbonization treatment is 800 - 1500 °C.

[0042] In some preferred embodiments of the present invention, the sintering temperature of the carbonization treatment is 1000 - 1300 °C.

[0043] In some embodiments of the present invention, the sintering time of the carbonization treatment is 20 seconds - 30 minutes.

[0044] In some preferred embodiments of the present invention, the sintering time of the carbonization treatment is 10 - 25 minutes.

[0045] In some embodiments of the present invention, in step S4, after natural cooling to room temperature, the carbonized material is taken out, and then ground and pulverized, and the hard carbon material is obtained after screening. The winding speed of the roll-to-roll process depends on the required sintering time and the size of the plasma region. The present invention adopts a conveying process to mass-produce hard carbon materials. The winding speed of the roll-to-roll process is determined according to the required sintering time and the scale of the plasma region, so as to effectively control the sintering time in the process of preparing the hard carbon negative electrode, further improving the production efficiency and reducing the cost. After determining parameters such as the sintering time and the scale of the plasma region, the winding speed can also be determined accordingly. For example, the winding speed of the roll-to-roll process is 0.01 - 10 rpm.

[0046] In some embodiments of the present invention, in step S4, after natural cooling to room temperature, the carbonized material is taken out, and then ground and pulverized, and the hard carbon material is obtained after screening.

[0047] The preparation method of the hard carbon anode material provided by the present invention uses dielectric barrier discharge plasma (DBD) to assist in rapid sintering for the large-scale preparation of the hard carbon anode material. This preparation method has a fast temperature rise rate (100 - 1000 °C / minute), a short sintering time (20 seconds - 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 achieve the rapid large-scale preparation and production of the hard carbon anode material, improve production efficiency, and reduce costs; the raw materials have a wide range of sources, and minerals, biomass, chemical products, etc. can be used as carbon sources; moreover, the microstructure and doping characteristics of the hard carbon anode material can be adjusted according to the temperature rise rate, sintering time, conveying speed, etc. The hard carbon material prepared by the above method is used as the anode material of a sodium-ion battery, showing excellent sodium storage performance.

[0048] In the second aspect of the present invention, a hard carbon anode material is proposed, and the hard carbon anode material is prepared by the large-scale preparation method of the hard carbon anode material as described above.

[0049] The hard carbon anode material according to the embodiment of the present invention has at least the following beneficial effects: The hard carbon anode material of the present invention is prepared by using the dielectric barrier discharge plasma (DBD) assisted conveying rapid carbonization method. On the one hand, the raw materials have a wide range of sources, including minerals, biomass, and chemical products as carbon sources, including but not limited to at least one or a mixture of coal-based or biomass-based materials such as anthracite, sucrose, starch, straw, resin, asphalt, coke, wood, bamboo, coconut shell, etc.; on the other hand, the microstructure and doping characteristics of the hard carbon anode material can be adjusted according to the DBD discharge parameters, temperature rise rate, sintering time, conveying speed, etc. When this hard carbon material is used as the anode material of a sodium-ion battery, matching the cathode material and the electrolyte, it shows excellent sodium storage performance.

[0050] In the third aspect of the present invention, an application of the large-scale preparation method of the hard carbon anode material as described above in the preparation of a battery anode material is proposed.

[0051] The application according to the embodiments of the present invention has at least the following beneficial effects: The present invention proposes an application of a dielectric barrier discharge plasma (DBD) assisted transfer rapid carbonization method in the large-scale preparation of hard carbon anode materials, and realizes its application in the preparation of battery anode materials. This preparation method has a fast temperature rise rate (100 - 1000 °C / minute), a short sintering time (20 seconds - 30 minutes), low energy consumption, can be prepared under atmospheric pressure conditions, and can realize the rapid large-scale preparation and production of hard carbon anode materials. Moreover, the raw materials are widely sourced, and the microstructure and doping characteristics of the hard carbon anode materials can be effectively regulated according to the temperature rise rate, sintering time, transfer speed, etc. Applying the above method to the preparation of battery anode materials can realize the large-scale preparation and production of anode materials, improve production efficiency, and reduce costs; the prepared hard carbon materials are used in secondary batteries such as sodium-ion batteries or lithium-ion batteries, showing excellent sodium storage performance.

[0052] In the fourth aspect of the present invention, a negative electrode sheet is proposed, which includes the hard carbon anode material as described above.

[0053] The negative electrode sheet of the present invention includes a current collector and a battery anode material. The battery anode material includes a negative electrode active material, a conductive agent, and a binder. The negative electrode active material is the above-mentioned hard carbon anode material or the hard carbon anode material prepared by using the above-mentioned preparation method. The negative electrode sheet prepared in the embodiments of the present invention is subjected to electrochemical tests and has excellent sodium storage performance.

[0054] In some embodiments of the present invention, the conductive agent is selected from acetylene black, conductive carbon black, graphite, but is not limited thereto, and common conductive aids in the art can be used to improve the conductivity of electrons generated in the electrode and improve battery performance.

[0055] 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), poly(methyl acrylate) (PMA), poly(methyl methacrylate) (PMMA), but is not limited thereto, and common negative electrode material binders in the art can be used, and PVDF is usually used.

[0056] In some embodiments of the present invention, the current collector is an inactive conductive current collector, and 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.

[0057] In the fifth aspect of the present invention, a battery is proposed, which includes the negative electrode sheet as described above.

[0058] In some embodiments of the present invention, the battery includes a half-battery and a full-battery, but is not limited thereto. The negative electrode plate provided by the present invention can also be used as an energy storage device such as a supercapacitor and a hybrid supercapacitor. Among them, there are no restrictions on the positive electrode active materials, diaphragms, electrolytes, etc. of the assembled battery, and the materials commonly used in the art can be reasonably adopted, which will not be repeated here.

[0059] In some embodiments of the invention, the battery comprises a sodium ion battery.

[0060] The present invention uses the hard carbon material as the negative electrode active material of the sodium ion battery to prepare the negative electrode plate, and the metal sodium plate is used as the reference electrode and the counter electrode, which are assembled with the electrolyte into a sodium ion half-cell. Electrochemical testing is carried out, and the battery has excellent sodium storage performance.

[0061] Preferably, the method for preparing the sodium ion half-cell comprises the steps of:

[0062] S100: Preparation of hard carbon negative electrode sheet: weigh the above-mentioned hard carbon active material, conductive agent and binder in a certain proportion, add them into a suitable solvent and mix them thoroughly into a uniform slurry to form a negative electrode active material layer; clean the negative electrode current collector, and then evenly apply the negative electrode active material layer on the surface of the negative electrode current collector, and then vacuum dry it. After the negative electrode active material layer is completely dried, cut it to obtain a negative electrode sheet of the required 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.

[0063] S200: Preparation of sodium metal pole piece: Cut the sodium metal foil into discs and place them in a glove box for standby use. Preferably, the thickness is 0.5 mm and the diameter of the disc is 14 mm.

[0064] S300: Electrolyte preparation: Weigh appropriate sodium salt and dissolve it in the solvent, stir it thoroughly and evenly to prepare the sodium ion storage battery electrolyte. The above operations are all carried out in an argon glove box (water and oxygen content are all less than 0.1ppm). 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).

[0065] S400: Assembling of sodium ion half-cell: assembling the negative electrode shell, sodium metal electrode sheet, diaphragm, hard carbon negative electrode sheet, gasket, spring, and positive electrode shell in sequence, pressing and sealing the battery after the assembly is completed, and placing the battery at room temperature. The preferred diaphragm is a PP diaphragm.

[0066] 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 of steps S100 - S300 can be performed simultaneously or in any order. Brief Description of the Drawings

[0067] The present invention will be further described below in conjunction with the drawings and embodiments, where:

[0068] Figure 1 Schematic diagram of the device for the large - scale preparation of dielectric barrier discharge plasma (DBD) - assisted rapid sintering in an embodiment of the present invention;

[0069] Figure 2 Transmission electron micrograph of the hard carbon material prepared in an embodiment of the present invention;

[0070] Figure 3 Schematic diagram of the typical charge - discharge curve of the hard carbon material prepared in an embodiment of the present invention when used as a sodium - ion half - cell. Detailed Embodiments

[0071] The following will clearly and completely describe the concept of the present invention and the technical effects produced in conjunction with the embodiments, so as to fully understand the purpose, features and effects of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all embodiments. Based on the embodiments of the present invention, other embodiments obtained by those skilled in the art without creative efforts shall fall within the scope of protection of the present invention.

[0072] In the description of the present invention, the reference to terms such as "one embodiment", "some embodiments", "schematic embodiments", "examples", "specific examples", or "some examples" etc. means that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in a suitable manner in any one or more embodiments or examples.

[0073] In the description of the present invention, unless otherwise specified, the numerical range "a~b" represents the abbreviated representation of any real - number combination between a and b, where a and b are both real numbers. Unless otherwise specified, each reaction or operation step can be carried out in sequence or not in sequence. Preferably, the reaction method in the present invention is carried out in sequence.

[0074] In the following examples, where specific techniques or conditions are not indicated, they shall be in accordance with the techniques or conditions described in the literature in this field or in accordance with the product specifications. All reagents or instruments without indicating the manufacturer can be obtained as conventional products through commercial purchases.

[0075] Example 1:

[0076] Preparation and application of hard carbon materials:

[0077] (1) Place starch in a tubular furnace and heat-treat and dry it in air at 160 °C.

[0078] (2) Then, pre-treat it for 2 hours under an argon atmosphere at 500 °C, naturally cool it to room temperature, and then grind and crush the pre-treated material to obtain black powder, completing the pre-carbonization of the carbon source material.

[0079] (3) Place the pre-carbonized powder material in a dielectric barrier discharge plasma (DBD) assisted sintering device (with a power density of 3 kW / m 2 , and the distance between the upper and lower insulating and heat-conducting plates is 5 mm), heat it to 1250 °C at a rate of 200 °C / min, maintain the sintering time for 25 minutes, and the conveying speed is 0.02 rpm.

[0080] (4) Naturally cool it to room temperature to obtain the carbonized material, take it out and grind and crush it, and obtain the starch-derived hard carbon material after screening.

[0081] (5) Using the above hard carbon material as the active material, prepare a hard carbon negative electrode sheet, use 1 M NaPF6 in EC:DMC:EMC (1:1:1, v:v:v) as the electrolyte, assemble a sodium ion half-cell, and use a battery testing system to test the half-cell.

[0082] Example 2:

[0083] Preparation and application of hard carbon materials:

[0084] (1) Place sucrose in a tubular furnace, heat-treat and dry it in air at 160 °C, and then crush it to form a powder material.

[0085] (2) Then, pre-treat it for 2 hours under an argon atmosphere at 500 °C, naturally cool it to room temperature, and then grind and crush the pre-treated material to obtain black powder, completing the pre-carbonization of the carbon source material.

[0086] (3) Place the pre-carbonized powder material in a dielectric barrier discharge plasma (DBD) assisted sintering device (with a power density of 3 kW / m 2, in the medium with a distance of 5 mm between the upper and lower insulating and heat-conducting plates, heat it to 1250 °C at a rate of 200 °C / min, maintain the sintering time for 25 minutes, and the conveying speed is 0.02 rpm;

[0087] (4) Naturally cool to room temperature to obtain the carbonized material, take it out, grind and crush it, and obtain the starch-derived hard carbon material after screening.

[0088] (5) Using the above hard carbon material as the active material, prepare a hard carbon negative electrode sheet, use 1 M NaPF6 in EC:DMC:EMC (1:1:1, v:v:v) as the electrolyte, assemble a sodium-ion half-cell, and use a battery test system to test the half-cell.

[0089] Example 3:

[0090] Preparation and application of hard carbon material:

[0091] (1) Place anthracite in a tubular furnace, heat-treat and dry it in air at 160 °C, and then crush it to form a powder material;

[0092] (2) Place the anthracite powder material in a dielectric barrier discharge plasma (DBD) assisted sintering device (using a power density of 3 kW / m 2 , in the medium with a distance of 5 mm between the upper and lower insulating and heat-conducting plates, heat it to 1250 °C at a rate of 200 °C / min, maintain the sintering time for 25 minutes, and the conveying speed is 0.02 rpm;

[0093] (3) Naturally cool to room temperature to obtain the carbonized material, take it out, grind and crush it, and obtain the starch-derived hard carbon material after screening.

[0094] (4) Using the above hard carbon material as the active material, prepare a hard carbon negative electrode sheet, use 1 M NaPF6 in EC:DMC:EMC (1:1:1, v:v:v) as the electrolyte, assemble a sodium-ion half-cell, and use a battery test system to test the half-cell.

[0095] Example 4:

[0096] Preparation and application of hard carbon material:

[0097] (1) Place starch in a tubular furnace, heat-treat and dry it in air at 160 °C, and then crush it to form a powder material;

[0098] (2) Then pre-treat it for 2 hours under an argon atmosphere at 500 °C, naturally cool to room temperature, and then grind and crush the pre-treated material to obtain a black powder, completing the pre-carbonization of the carbon source material;

[0099] (3) Place the pre-carbonized powder material in a dielectric barrier discharge plasma (DBD) assisted sintering device (with a power density of 3 kW / m 2 , and the distance between the upper and lower insulating heat conducting plates is 5 mm), heat it up to 1100 °C at a rate of 200 °C / min, maintain the sintering time for 25 minutes, and the conveying speed is 0.02 rpm;

[0100] (4) Naturally cool to room temperature to obtain the carbonized material, take it out, grind and crush it, and obtain the starch-derived hard carbon material after screening.

[0101] (5) Using the above hard carbon material as the active material, prepare a hard carbon negative electrode sheet, use 1M NaPF6 in EC:DMC:EMC (1:1:1, v:v:v) as the electrolyte, assemble a sodium ion half-cell, and use a battery testing system to test the half-cell.

[0102] Example 5:

[0103] Preparation and application of hard carbon materials:

[0104] (1) Place starch in a tubular furnace and heat-treat it in air at 160 °C for drying;

[0105] (2) Then pre-treat it in an argon atmosphere at 500 °C for 2 hours, naturally cool to room temperature, and then grind and crush the pre-treated material to obtain a black powder, completing the pre-carbonization of the carbon source material.

[0106] (3) Place the pre-carbonized powder material in a dielectric barrier discharge plasma (DBD) assisted sintering device (with a power density of 3 kW / m 2 , and the distance between the upper and lower insulating heat conducting plates is 5 mm), heat it up to 1400 °C at a rate of 200 °C / min, maintain the sintering time for 25 minutes, and the conveying speed is 0.02 rpm;

[0107] (4) Naturally cool to room temperature to obtain the carbonized material, take it out, grind and crush it, and obtain the starch-derived hard carbon material after screening.

[0108] (5) Using the above hard carbon material as the active material, prepare a hard carbon negative electrode sheet, use 1M NaPF6 in EC:DMC:EMC (1:1:1, v:v:v) as the electrolyte, assemble a sodium ion half-cell, and use a battery testing system to test the half-cell.

[0109] Example 6:

[0110] Preparation and application of hard carbon materials:

[0111] (1) Place starch in a tubular furnace and heat-treat it in air at 160 °C for drying;

[0112] (2) Subsequently, it was pretreated for 2 hours under an argon atmosphere at 500 °C, naturally cooled to room temperature, and then the pre-treated material was ground and pulverized to obtain black powder, completing the pre-carbonization of the carbon source material.

[0113] (3) The pre-carbonized powder material was placed in a dielectric barrier discharge plasma (DBD) assisted sintering device (with a power density of 3 kW / m 2 and a distance of 5 mm between the upper and lower insulating and heat-conducting plates), heated to 1250 °C at a rate of 300 °C / min, maintained the sintering time for 25 minutes, and the conveying speed was 0.02 rpm.

[0114] (4) It was naturally cooled to room temperature to obtain the carbonized material, taken out and ground and pulverized, and the starch-derived hard carbon material was obtained after screening.

[0115] (5) Using the above hard carbon material as the active material, a hard carbon negative electrode sheet was prepared, 1 M NaPF6 in EC:DMC:EMC (1:1:1, v:v:v) was used as the electrolyte, a sodium ion half-cell was assembled, and the half-cell was tested using a battery testing system.

[0116] Example 7:

[0117] Preparation and application of hard carbon material:

[0118] (1) Starch was placed in a tubular furnace and heat-treated and dried in air at 160 °C;

[0119] (2) Subsequently, it was pretreated for 2 hours under an argon atmosphere at 500 °C, naturally cooled to room temperature, and then the pre-treated material was ground and pulverized to obtain black powder, completing the pre-carbonization of the carbon source material.

[0120] (3) The pre-carbonized powder material was placed in a dielectric barrier discharge plasma (DBD) assisted sintering device (with a power density of 3 kW / m 2 and a distance of 5 mm between the upper and lower insulating and heat-conducting plates), heated to 1250 °C at a rate of 400 °C / min, maintained the sintering time for 25 minutes, and the conveying speed was 0.02 rpm.

[0121] (4) It was naturally cooled to room temperature to obtain the carbonized material, taken out and ground and pulverized, and the starch-derived hard carbon material was obtained after screening.

[0122] (5) Using the above hard carbon material as the active material, a hard carbon negative electrode sheet was prepared, 1 M NaPF6 in EC:DMC:EMC (1:1:1, v:v:v) was used as the electrolyte, a sodium ion half-cell was assembled, and the half-cell was tested using a battery testing system.

[0123] Example 8:

[0124] Preparation and Application of Hard Carbon Materials:

[0125] (1) Place starch in a tube furnace and heat-treat and dry it in air at 160 °C;

[0126] (2) Then, pre-treat it for 2 hours in an argon atmosphere at 500 °C, naturally cool it to room temperature, and then grind and crush the pre-treated material to obtain black powder, completing the pre-carbonization of the carbon source material;

[0127] (3) Place the pre-carbonized powder material in a dielectric barrier discharge plasma (DBD) assisted sintering device (with a power density of 3 kW / m 2 , and the distance between the upper and lower insulating heat-conducting plates is 5 mm), heat it to 1250 °C at a rate of 200 °C / min, maintain the sintering time for 10 minutes, and the conveying speed is 0.05 rpm;

[0128] (4) Naturally cool it to room temperature to obtain the carbonized material, take it out and grind and crush it, and obtain the starch-derived hard carbon material after screening.

[0129] (5) Using the above hard carbon material as the active material, prepare a hard carbon negative electrode sheet, use 1 M NaPF6 in EC:DMC:EMC (1:1:1, v:v:v) as the electrolyte, assemble a sodium ion half-cell, and use a battery testing system to test the half-cell.

[0130] Example 9:

[0131] Preparation and Application of Hard Carbon Materials:

[0132] (1) Place starch in a tube furnace and heat-treat and dry it in air at 160 °C;

[0133] (2) Then, pre-treat it for 2 hours in an argon atmosphere at 500 °C, naturally cool it to room temperature, and then grind and crush the pre-treated material to obtain black powder, completing the pre-carbonization of the carbon source material;

[0134] (3) Place the pre-carbonized powder material in a dielectric barrier discharge plasma (DBD) assisted sintering device (with a power density of 3 kW / m 2 , and the distance between the upper and lower insulating heat-conducting plates is 5 mm), heat it to 1250 °C at a rate of 200 °C / min, maintain the sintering time for 5 minutes, and the conveying speed is 0.1 rpm;

[0135] (4) Naturally cool it to room temperature to obtain the carbonized material, take it out and grind and crush it, and obtain the starch-derived hard carbon material after screening.

[0136] (5) Using the above hard carbon material as the active material, prepare a hard carbon negative electrode sheet. Using 1M NaPF6 in EC:DMC:EMC (1:1:1, v:v:v) as the electrolyte, assemble a sodium-ion half-cell, and use a battery testing system to test the half-cell.

[0137] Example 10:

[0138] Preparation and application of hard carbon material:

[0139] (1) Place the starch and anthracite mixed material in a tubular furnace, and after heat treatment and drying in air at 160 °C;

[0140] (2) Then, pre-treat for 2 hours under an argon atmosphere at 500 °C, naturally cool to room temperature, and then grind and crush the pre-treated material to obtain a black powder, completing the pre-carbonization of the carbon source material;

[0141] (3) Place the pre-carbonized powder material in a dielectric barrier discharge plasma (DBD) assisted sintering device (with a power density of 3 kW / m 2 , and the distance between the upper and lower insulating and heat-conducting plates is 5 mm), heat up to 1250 °C at a rate of 200 °C / min, maintain the sintering time for 25 minutes, and the conveying speed is 0.02 rpm;

[0142] (4) Naturally cool to room temperature to obtain the carbonized material, take it out, grind and crush it, and obtain the starch-derived hard carbon material after screening.

[0143] (5) Using the above hard carbon material as the active material, prepare a hard carbon negative electrode sheet. Using 1M NaPF6 in EC:DMC:EMC (1:1:1, v:v:v) as the electrolyte, assemble a sodium-ion half-cell, and use a battery testing system to test the half-cell.

[0144] Example 11:

[0145] Preparation and application of hard carbon material:

[0146] (1) Place the starch in a tubular furnace, and after heat treatment and drying in air at 160 °C;

[0147] (2) Then, pre-treat for 2 hours under an argon atmosphere at 500 °C, naturally cool to room temperature, and then grind and crush the pre-treated material to obtain a black powder, completing the pre-carbonization of the carbon source material;

[0148] (3) Place the pre-carbonized powder material in a dielectric barrier discharge plasma (DBD) assisted sintering device (with a power density of 5 kW / m 2, in the upper and lower insulating and heat-conducting plates with a spacing of 5 mm, heat up to 1250 °C at a rate of 200 °C / min, maintain the sintering time for 25 minutes, and the conveying speed is 0.02 rpm;

[0149] (4) Naturally cool to room temperature to obtain the carbonized material, take it out, grind and crush it, and obtain the starch-derived hard carbon material after screening.

[0150] (5) Using the above hard carbon material as the active material, prepare a hard carbon negative electrode sheet, use 1 M NaPF6 in EC:DMC:EMC (1:1:1, v:v:v) as the electrolyte, assemble a sodium-ion half-cell, and use a battery testing system to test the half-cell.

[0151] Example 12:

[0152] Preparation and application of hard carbon materials:

[0153] (1) Place starch in a tubular furnace and heat-treat and dry it in air at 160 °C;

[0154] (2) Then pre-treat it for 2 hours in an argon atmosphere at 500 °C, naturally cool to room temperature, and then grind and crush the pre-treated material to obtain black powder, completing the pre-carbonization of the carbon source material.

[0155] (3) Place the pre-carbonized powder material in a dielectric barrier discharge plasma (DBD) assisted sintering device (using a power density of 3 kW / m 2 , with the upper and lower insulating and heat-conducting plates having a spacing of 3 mm), heat up to 1250 °C at a rate of 200 °C / min, maintain the sintering time for 25 minutes, and the conveying speed is 0.02 rpm;

[0156] (4) Naturally cool to room temperature to obtain the carbonized material, take it out, grind and crush it, and obtain the starch-derived hard carbon material after screening.

[0157] (5) Using the above hard carbon material as the active material, prepare a hard carbon negative electrode sheet, use 1 M NaPF6 in EC:DMC:EMC (1:1:1, v:v:v) as the electrolyte, assemble a sodium-ion half-cell, and use a battery testing system to test the half-cell.

[0158] Example 13:

[0159] Preparation and application of hard carbon materials:

[0160] (1) Place bamboo in a tubular furnace and heat-treat and dry it in air at 160 °C;

[0161] (2) Then, it was pretreated for 2 hours under an argon atmosphere at 500 °C, naturally cooled to room temperature, and then the pre-treated material was ground and pulverized to obtain black powder, completing the pre-carbonization of the carbon source material.

[0162] (3) The pre-carbonized powder material was placed in a dielectric barrier discharge plasma (DBD) assisted sintering device (with a power density of 3 kW / m 2 , and the distance between the upper and lower insulating and heat-conducting plates was 3 mm), heated to 1250 °C at a rate of 200 °C / min, maintained the sintering time for 25 minutes, and the conveying speed was 0.02 rpm.

[0163] (4) It was naturally cooled to room temperature to obtain the carbonized material, taken out and ground and pulverized, and after screening, the starch-derived hard carbon material was obtained.

[0164] (5) Using the above hard carbon material as the active material, a hard carbon negative electrode sheet was prepared, using 1 M NaPF6 in EC:DMC:EMC (1:1:1, v:v:v) as the electrolyte, assembling a sodium ion half-cell, and using a battery test system to test the half-cell.

[0165] Example 14:

[0166] Preparation and application of hard carbon material:

[0167] (1) The coconut shell was placed in a tube furnace and heat-treated and dried in air at 160 °C;

[0168] (2) Then, it was pretreated for 2 hours under an argon atmosphere at 500 °C, naturally cooled to room temperature, and then the pre-treated material was ground and pulverized to obtain black powder, completing the pre-carbonization of the carbon source material.

[0169] (3) The pre-carbonized powder material was placed in a dielectric barrier discharge plasma (DBD) assisted sintering device (with a power density of 3 kW / m 2 , and the distance between the upper and lower insulating and heat-conducting plates was 3 mm), heated to 1250 °C at a rate of 200 °C / min, maintained the sintering time for 25 minutes, and the conveying speed was 0.02 rpm.

[0170] (4) It was naturally cooled to room temperature to obtain the carbonized material, taken out and ground and pulverized, and after screening, the starch-derived hard carbon material was obtained.

[0171] (5) Using the above hard carbon material as the active material, a hard carbon negative electrode sheet was prepared, using 1 M NaPF6 in EC:DMC:EMC (1:1:1, v:v:v) as the electrolyte, assembling a sodium ion half-cell, and using a battery test system to test the half-cell.

[0172] Example 15:

[0173] Preparation and Application of Hard Carbon Materials

[0174] (1) Place walnut shells in a tube furnace and heat-treat and dry them in air at 160 °C;

[0175] (2) Then, pre-treat them for 2 hours in an argon atmosphere at 500 °C, naturally cool them to room temperature, and then grind and crush the pre-treated materials to obtain black powder, completing the pre-carbonization of the carbon source materials;

[0176] (3) Place the pre-carbonized powder materials in a dielectric barrier discharge plasma (DBD) assisted sintering device (with a power density of 3 kW / m 2 , and the distance between the upper and lower insulating and heat-conducting plates is 3 mm), heat them to 1250 °C at a rate of 200 °C / min, maintain the sintering time for 25 minutes, and the conveying speed is 0.02 rpm;

[0177] (4) Naturally cool them to room temperature to obtain the carbonized materials, take them out, grind and crush them, and obtain starch-derived hard carbon materials after screening.

[0178] (5) Using the above hard carbon materials as active materials, prepare hard carbon negative electrode sheets, use 1M NaPF6 in EC:DMC:EMC (1:1:1, v:v:v) as the electrolyte, assemble sodium ion half-cells, and use a battery test system to test the half-cells.

[0179] Example 16:

[0180] Preparation and Application of Hard Carbon Materials

[0181] (1) Place phenolic resin in a tube furnace and heat-treat and dry them in air at 160 °C;

[0182] (2) Then, pre-treat them for 2 hours in an argon atmosphere at 500 °C, naturally cool them to room temperature, and then grind and crush the pre-treated materials to obtain black powder, completing the pre-carbonization of the carbon source materials;

[0183] (3) Place the pre-carbonized powder materials in a dielectric barrier discharge plasma (DBD) assisted sintering device (with a power density of 3 kW / m 2 , and the distance between the upper and lower insulating and heat-conducting plates is 3 mm), heat them to 1250 °C at a rate of 200 °C / min, maintain the sintering time for 25 minutes, and the conveying speed is 0.02 rpm;

[0184] (4) Naturally cool them to room temperature to obtain the carbonized materials, take them out, grind and crush them, and obtain starch-derived hard carbon materials after screening.

[0185] (5) Using the above hard carbon material as the active material, prepare a hard carbon negative electrode sheet, use 1M NaPF6 in EC:DMC:EMC (1:1:1, v:v:v) as the electrolyte, assemble a sodium-ion half-cell, and use a battery testing system to test the half-cell.

[0186] Example 17:

[0187] Preparation and application of hard carbon material:

[0188] (1) Place polyacrylonitrile in a tube furnace, and after heat treatment and drying in air at 160 °C;

[0189] (2) Then, pretreat it for 2 hours under an argon atmosphere at 500 °C, naturally cool it to room temperature, and then grind and crush the pretreated material to obtain black powder, completing the pre-carbonization of the carbon source material.

[0190] (3) Place the pre-carbonized powder material in a dielectric barrier discharge plasma (DBD) assisted sintering device (with a power density of 3 kW / m 2 , and the distance between the upper and lower insulating and heat-conducting plates is 3 mm), heat it to 1250 °C at a rate of 200 °C / min, maintain the sintering time for 25 minutes, and the conveying speed is 0.02 rpm;

[0191] (4) Naturally cool it to room temperature to obtain the carbonized material, take it out and grind and crush it, and obtain the starch-derived hard carbon material after screening.

[0192] (5) Using the above hard carbon material as the active material, prepare a hard carbon negative electrode sheet, use 1M NaPF6 in EC:DMC:EMC (1:1:1, v:v:v) as the electrolyte, assemble a sodium-ion half-cell, and use a battery testing system to test the half-cell.

[0193] Example 18:

[0194] Preparation and application of hard carbon material:

[0195] (1) Place pomelo peel in a tube furnace, and after heat treatment and drying in air at 160 °C;

[0196] (2) Then, pretreat it for 2 hours under an argon atmosphere at 500 °C, naturally cool it to room temperature, and then grind and crush the pretreated material to obtain black powder, completing the pre-carbonization of the carbon source material.

[0197] (3) Place the pre-carbonized powder material in a dielectric barrier discharge plasma (DBD) assisted sintering device (with a power density of 3 kW / m 2, in the upper and lower insulating and heat-conducting plates with a spacing of 3 mm, the temperature is raised to 1250 °C at a rate of 200 °C / min, the sintering time is maintained for 25 minutes, and the conveying speed is 0.02 rpm;

[0198] (4) Naturally cool to room temperature to obtain the carbonized material, take it out, grind and crush it, and obtain the starch-derived hard carbon material after screening.

[0199] (5) Using the above hard carbon material as the active material, prepare a hard carbon negative electrode sheet, use 1 M NaPF6 in EC:DMC:EMC (1:1:1, v:v:v) as the electrolyte, assemble a sodium-ion half-cell, and use a battery testing system to test the half-cell.

[0200] The carbon components of the materials prepared in Examples 1-18 and the electrochemical performance of the half-cells were tested respectively (including specific capacity, first efficiency, capacity retention rate, etc., and the method refers to the conventional testing methods in the art), and the results are shown in Table 1.

[0201] Table 1

[0202]

[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 adjusting the key parameters, and the electrochemical performance of the obtained hard carbon material can be optimized.

[0204] The above embodiments only represent several implementation manners of the present invention, and the description is relatively specific and detailed, but it should not be construed as a limitation on the scope of the patent of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present invention, several modifications and improvements can still be made, and these all belong to the protection scope of the present invention.

Claims

1. A preparation method of a hard carbon negative electrode material, characterized in that, Including the steps: 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 to 200 °C, preferably 150 to 200 °C; and / or, the time of the drying treatment is 1 to 10 hours, preferably 1 to 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 to 800 °C, preferably 500 to 550 °C; and / or, the time of the pre-carbonization treatment is 1 to 10 hours, preferably 2 to 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 of the carbonization treatment are an inert gas atmosphere; and / or, the temperature rise rate is 100 to 1000 °C / minute, preferably 200 to 500 °C / minute; and / or, the sintering temperature is 800 to 1500 °C, preferably 1000 to 1300 °C; and / or, the sintering time is 20 seconds to 30 minutes, preferably 10 to 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 sheet, characterized in that, Including the hard carbon negative electrode material according to claim 7.

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

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