A pre-sodiated sodium-ion battery negative electrode material and a preparation method and application thereof

Abstract

The embodiment of the present application relates to a kind of pre-sodium sodium ion battery negative materials and its preparation method and application, the preparation method includes: carbon precursor is mixed with sodium hydroxide according to certain mass ratio and grinds, obtains mixed powder;In inert atmosphere, mixed powder is placed in rotary furnace and is activated to handle, to make sodium hydroxide decompose and be reduced by carbon in carbon precursor, simultaneously, carbon precursor is etched, so that carbon precursor forms pore structure, obtains pre-sodium porous carbon material;In rotary furnace, pre-sodium porous carbon material is coated by chemical vapor deposition, obtains pre-sodium sodium ion battery negative material.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of sodium ion battery negative electrode materials, and particularly relates to a pre-sodiumized sodium ion battery negative electrode material and a preparation method and application thereof. BACKGROUND

[0002] A sodium ion battery is a kind of secondary battery, and sodium and lithium belong to the same alkali group and have similar physicochemical properties. Compared with a lithium ion battery, the sodium ion battery has the following advantages: abundant sodium resources, low cost, high energy density, and good temperature tolerance.

[0003] The working principle of the sodium ion battery is similar to that of the lithium ion battery, and the sodium ion battery mainly works by moving sodium ions between the positive electrode and the negative electrode. Similarly, the formation of an SEI film and the occurrence of a side reaction during the first charging and discharging process consume sodium ions in the battery system, resulting in a decrease in the initial efficiency.

[0004] The most common method for improving the initial efficiency at present is to reduce the ash content and the specific surface area. Reducing the ash content can reduce the occurrence of side reactions and reduce the consumption of sodium ions. Reducing the specific surface area reduces the contact area between the electrolyte and the electrode surface, reduces the formation area of the SEI film, and reduces the consumption of sodium ions. In addition, the reduction of the specific surface area can reduce the phenomenon that sodium ions enter the small pore structure and cannot be discharged. Although reducing the ash content and the specific surface area can improve the initial efficiency to a certain extent, they cannot fundamentally solve the consumption of sodium ions caused by the formation of the SEI film. Moreover, the reduction of the ash content and the specific surface area is limited by the material itself, and the reduction of the ash content currently commonly used is acid washing. The increase of the acid washing process will sharply increase the cost of the material, which is not conducive to the low manufacturing cost advantage of the sodium battery. SUMMARY

[0005] The present application aims at the defects of the prior art, and provides a pre-sodiumized sodium ion battery negative electrode material and a preparation method and application thereof. The high-temperature activation process in the preparation method enables the carbon precursor to form a pore structure, and generates Na2O or Na with high activity in the pores. The chemical vapor deposition performs closed pore treatment on the pore structure, protects the high-activity Na2O or Na in the pores, achieves the pre-sodium effect, reduces the specific surface area, reduces the generation of the SEI film, and improves the initial efficiency problem of the material.

[0006] To achieve the above-mentioned purpose, in a first aspect, the present application provides a preparation method of a pre-sodiumized sodium ion battery negative electrode material, which comprises:

[0007] The carbon precursor and sodium hydroxide are mixed and ground according to a certain mass ratio to obtain a mixed powder.

[0008] activating the mixed powder in a rotary furnace under inert atmosphere to decompose the sodium hydroxide and reduce the sodium hydroxide by carbon in the carbon precursor, and etching the carbon precursor to form a porous structure of the carbon precursor, thereby obtaining a pre-sodium porous carbon material;

[0009] coating the pre-sodium porous carbon material by chemical vapor deposition in the rotary furnace, thereby obtaining a pre-sodiumized sodium-ion battery negative electrode material.

[0010] Preferably, the mass ratio of the carbon precursor to sodium hydroxide is 1:10-5:1.

[0011] Preferably, the temperature of the activation treatment is 500-1200℃, and the time of the activation treatment is 1-12 hours.

[0012] Preferably, the carbon precursor includes one or more of walnut shell, coconut shell, nut shell, kelp, pomelo peel, lotus root, eggshell membrane, cork, coconut shell, straw, starch, renewable cotton, polyaniline, lignin, cellulose, hemicellulose, honeycomb coal, chitosan, pitch, phenolic resin, glucose, magnesium gluconate, polyvinylpyrrolidone, graphene oxide, graphene, xylose, epoxy resin, petroleum coke, or a product after high-temperature treatment of the above-mentioned substances, wherein the temperature of the high-temperature treatment is 800-1800℃.

[0013] Preferably, the gas for chemical vapor deposition includes carbon source gas and protective gas, and the volume ratio of the carbon source gas to the protective gas is 1:5-5:1.

[0014] Preferably, the carbon source gas is one or more of methane, acetylene, ethylene, propylene, or carbon monoxide, and the protective gas is one or more of nitrogen, helium, or argon.

[0015] Preferably, the conditions for chemical vapor deposition are as follows: deposition temperature 500-900℃, and deposition time 0.5-12 hours.

[0016] In a second aspect, the present application provides a pre-sodiumized sodium-ion battery negative electrode material, which is prepared by the preparation method of any one of the first aspect.

[0017] In a third aspect, the present application provides a negative electrode sheet, which includes the pre-sodiumized sodium-ion battery negative electrode material of the second aspect.

[0018] In a fourth aspect, the present application provides a sodium-ion battery, which includes the negative electrode sheet of the third aspect.

[0019] The preparation method of the pre-sodiumized sodium ion battery negative electrode material provided by the embodiment of the present application achieves the effect of pre-sodiumizing the carbon-based negative electrode through the processes of mixing and grinding, high-temperature activation, chemical vapor deposition, etc., wherein the high-temperature activation and the chemical vapor deposition are both carried out in a rotary furnace, realizing the continuity of the preparation process and reducing the complexity of the conversion between processes, which is conducive to large-scale production. The activation process enables the carbon precursor to form a pore structure, and with the by-product in the sodium hydroxide activation process, a high-activity Na2O or Na is generated in the pores to pre-sodiumize the negative electrode material. In this way, the sodium ions can be supplemented, the sodium content in the battery system can be increased, the consumption of the electrolyte can be reduced, and the consumption of sodium ions in the formation process of the solid electrolyte interface film can be compensated. The pore structure is closed by chemical vapor deposition to protect the high-activity Na2O or Na in the pores, enhance the pre-sodium effect, reduce the specific surface area, reduce the generation of the SEI film, and improve the first efficiency problem of the material. BRIEF DESCRIPTION OF DRAWINGS

[0020] Figure 1 The flow chart of the preparation method of the pre-sodiumized sodium ion battery negative electrode material provided by the embodiment of the present application is shown in

[0021] Figure 2 The charge-discharge curve graph of the button half-cell assembled by the embodiment 1-5 and the comparative example 2 of the present application is shown in

[0022] Figure 3 The first efficiency data statistical graph of the button half-cell assembled by the embodiment 1-5 and the comparative example 2 of the present application is shown in

[0023] Figure 4 The initial voltage data statistical graph of the button half-cell assembled by the embodiment 1-5 and the comparative example 2 of the present application is shown in DETAILED DESCRIPTION

[0024] In order to make the purpose, technical scheme and advantages of the present application clearer, the present application will be further described in detail below with reference to the drawings. Obviously, the described embodiments are only some of the embodiments of the present application, but not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0025] The technical scheme of the present application will be further described in detail below with reference to the drawings and embodiments.

[0026] The embodiment of the present application provides a preparation method of a pre-sodiumized sodium ion battery negative electrode material, the process of which is as shown in Figure 1 The preparation method comprises the following steps:

[0027] Step 110, mix the carbon precursor and sodium hydroxide according to a certain mass ratio and grind to obtain a mixed powder;

[0028] Specifically, the mass ratio of the carbon precursor to sodium hydroxide can be 1:10-5:1, preferably 1:3. The carbon precursor can specifically include one or more of walnut shell, coconut shell, nut shell, kelp, pomelo peel, lotus root, eggshell membrane, cork, coconut shell, straw, starch, renewable cotton, polyaniline, lignin, cellulose, hemicellulose, honeycomb coal, chitosan, pitch, phenolic resin, glucose, magnesium gluconate, polyvinylpyrrolidone, graphene oxide, graphene, xylose, epoxy resin, petroleum coke, or products after high-temperature treatment of the above substances. The temperature of the high-temperature treatment can be specifically 800-1800°C.

[0029] Step 120, under an inert atmosphere, the mixed powder is placed in a rotary furnace for activation treatment, so that the sodium hydroxide is decomposed and reduced by carbon in the carbon precursor, and at the same time, the carbon precursor is etched to form a pore structure, and a pre-sodium porous carbon material is obtained;

[0030] Specifically, the inert atmosphere can specifically include one or more of nitrogen, helium or argon. The temperature of the activation treatment can be specifically 500-1200°C, preferably 800°C. The time of the activation treatment can be specifically 1-12 hours, preferably 6 hours. The flow rate of the nitrogen gas can be specifically 0.8-1.2 L / min, preferably 1 L / min. The pre-sodium porous carbon material includes the carbon precursor and sodium oxide, sodium element, etc. in the pore structure of the carbon precursor.

[0031] The chemical reaction equation occurring during the activation treatment is specifically as follows:

[0032] 2NaOH=Na2O+H2O

[0033] C+H2O=H2+CO

[0034] CO+H2O=H2+CO2

[0035]

[0036] C+Na2O=2Na+CO

[0037] It should be noted that the above chemical reaction equation only represents some chemical reactions that can occur during the activation process, for example, not all sodium oxide reacts with carbon to form sodium element, and not all sodium oxide reacts with carbon dioxide to form sodium carbonate.

[0038] The high-temperature activation process enables the carbon precursor to form a pore structure, and, with the aid of by-products in the decomposition process of sodium hydroxide, generates high-activity Na2O or Na in the pores.

[0039] At step 130, the pre-sodium porous carbon material is coated by chemical vapor deposition in a rotary furnace to obtain a pre-sodiumized sodium-ion battery negative electrode material.

[0040] Specifically, the gas for chemical vapor deposition can include a carbon source gas and a protective gas. The volume ratio of the carbon source gas to the protective gas is 1:5-5:1. The carbon source gas can be one or more of methane, acetylene, ethylene, propylene, or carbon monoxide. The gas flow rate when the carbon source gas is introduced can be specifically 0.1 L / min-1.0 L / min, preferably 0.8 L / min.

[0041] The protective gas can be one or more of nitrogen, helium, or argon. The gas flow rate when the protective gas is introduced can be specifically 0.1 L / min-1 L / min, preferably 0.2 L / min.

[0042] The conditions for chemical vapor deposition are as follows: the deposition temperature is specifically 500℃-900℃, preferably 800℃-900℃. The deposition time is specifically 0.5 hours-12 hours, preferably 1 hour-6 hours.

[0043] Chemical vapor deposition coats the pre-sodium porous carbon material, enabling the pore structure to form a closed pore structure, protecting the high-activity Na2O or Na in the pores, enhancing the pre-sodium effect, and reducing the specific surface area and the generation of SEI films.

[0044] As a preferred solution, if the carbon precursor is not subjected to high-temperature treatment, in order to improve the carbonization effect, after step 130, the preparation method further includes: further high-temperature carbonization treatment of the pre-sodiumized sodium-ion battery negative electrode material prepared, the conditions for high-temperature carbonization treatment: the temperature can be specifically 800℃-2000℃, the time can be 1 hour-12 hours, and the inert atmosphere can be one or more of nitrogen, helium, or argon.

[0045] Of course, it can be understood that the carbon precursor can also be subjected to high-temperature carbonization treatment before step 110.

[0046] The preparation method of the pre-sodiumized sodium ion battery negative electrode material provided by the embodiment of the present application achieves the effect of pre-sodiumizing the carbon-based negative electrode through processes such as mixing and grinding, high-temperature activation, and chemical vapor deposition. The high-temperature activation and the chemical vapor deposition are both performed in a rotary furnace, realizing the continuity of the preparation process and reducing the complexity of the conversion between processes, which is conducive to large-scale production. The activation process enables the carbon precursor to form a pore structure, and by-products generated during the activation of sodium hydroxide generate high-activity Na2O or Na in the pores, thereby pre-sodiumizing the negative electrode material. In this way, the sodium ions can be supplemented, the sodium content in the battery system can be increased, the consumption of the electrolyte can be reduced, and the consumption of sodium ions in the formation process of the solid electrolyte interface film can be compensated. The chemical vapor deposition is used to close the pores of the pore structure, protect the high-activity Na2O or Na in the pores, enhance the pre-sodium effect, reduce the specific surface area, reduce the generation of the SEI film, and improve the first efficiency problem of the material.

[0047] The pre-sodiumized sodium ion battery negative electrode material provided by the embodiment of the present application can be applied to the electrode material of a sodium ion battery.

[0048] In order to better understand the technical solutions provided by the present application, the following describes the specific process of preparing the pre-sodiumized sodium ion battery negative electrode material by using the method provided by the above embodiment of the present application, and the electrochemical properties of the prepared pre-sodiumized sodium ion battery negative electrode material.

[0049] Embodiment 1

[0050] In the first step, the walnut shell is subjected to high-temperature carbonization treatment under a nitrogen atmosphere at a temperature of 900 DEG C for 6 hours to obtain a walnut shell precursor.

[0051] In the second step, 100 g of the walnut shell precursor and 300 g of sodium hydroxide are weighed and mixed and ground to obtain a sodium hydroxide / walnut shell precursor mixed powder.

[0052] In the third step, the sodium hydroxide / walnut shell precursor mixed powder is placed in a rotary furnace for activation treatment under a nitrogen atmosphere with a gas flow of 1 L / min at a temperature of 800 DEG C for 6 hours, so that the sodium hydroxide is decomposed and reduced by the carbon in the walnut shell precursor, and at the same time, the walnut shell precursor is etched to form a pore structure, thereby obtaining a pre-sodiumized porous carbon material.

[0053] In the fourth step, the rotary furnace is continuously supplied with nitrogen at a gas flow of 0.2 L / min and methane at a gas flow of 0.8 L / min at a volume ratio of nitrogen to methane of 1:4 at a temperature of 800 DEG C for 6 hours, and the pre-sodiumized porous carbon material is coated by chemical vapor deposition to obtain a pre-sodiumized sodium ion battery negative electrode material.

[0054] Afterwards, the prepared pre-sodiumized sodium ion battery negative electrode material was used as the negative electrode plate of the sodium ion battery to assemble a button half-cell for testing, as follows:

[0055] First, add 0.375g of carboxymethyl cellulose (CMC) to 15g of deionized water and disperse it at a dispersion disk speed of 2000r / min for 30 minutes to obtain a clear glue solution. Add 0.3g of conductive carbon black (SP) to the glue solution and continue to disperse it at a dispersion disk speed of 2000r / min for 40 minutes to obtain a slurry. Add 14.175g of the prepared pre-sodiumized sodium ion battery negative electrode material to the slurry and continue to disperse it at a dispersion disk speed of 2000r / min for 40 minutes. Then add an appropriate amount of water to adjust the viscosity to 3000mPa.s. Then add 0.375g of styrene-butadiene rubber (SBR) emulsion (solid content of 40%) to the slurry at a dispersion disk speed of 1000r / min for 30 minutes. Then reduce the dispersion disk speed to 500r / min, slowly stir for 30 minutes, and remove the slurry. The slurry was coated on an aluminum foil current collector and dried in a vacuum oven at 80°C for 12 hours. The dried electrode was cut to serve as the negative electrode of the sodium ion battery.

[0056] Then, the negative electrode sheet was used to assemble a button-type sodium-ion half-cell. The aqueous electrolyte in the button-type sodium-ion half-cell was 1 mol / L sodium hexafluorophosphate (NaPF6), and the solvent was dimethyl ether (DME). The counter electrode was a sodium sheet.

[0057] Finally, electrochemical tests were performed to evaluate the electrochemical performance. The test conditions were: charge cut-off voltage of 2V, discharge cut-off voltage of 0V, and current density of 0.1C.

[0058] Example 2

[0059] In the first step, the walnut shell is subjected to high-temperature carbonization treatment at 900° C. for 6 hours under a nitrogen atmosphere to obtain a walnut shell precursor.

[0060] In the second step, 100 g of walnut shell precursor and 300 g of sodium hydroxide were weighed, mixed and ground to obtain a sodium hydroxide / walnut shell precursor mixed powder.

[0061] In the third step, the sodium hydroxide / walnut shell precursor mixed powder is placed in a rotary kiln for activation treatment under a nitrogen atmosphere with a gas flow rate of 1 L / min. The temperature is kept at 1000°C for 2 hours to decompose the sodium hydroxide and be reduced by the carbon in the walnut shell precursor. At the same time, the walnut shell precursor is etched to form a porous structure in the walnut shell precursor to obtain a pre-sodium porous carbon material.

[0062] The fourth step is to continue to introduce nitrogen gas at a gas flow rate of 0.2 L / min and methane at a gas flow rate of 0.8 L / min into the rotary furnace at a volume ratio of nitrogen gas to methane of 1:4, and to carry out coating on the pre-sodium porous carbon material by chemical vapor deposition at a temperature of 800 DEG C for 6 hours, so as to obtain a pre-sodium sodium-ion battery negative electrode material.

[0063] The assembly and test of the button-type half cell are the same as those of Example 1.

[0064] Example 3

[0065] The first step is to carry out high-temperature carbonization treatment on the walnut shell under a nitrogen atmosphere at a temperature of 900 DEG C for 6 hours, so as to obtain a walnut shell precursor.

[0066] The second step is to mix and grind 100 g of the walnut shell precursor and 300 g of sodium hydroxide, so as to obtain a sodium hydroxide / walnut shell precursor mixed powder.

[0067] The third step is to place the sodium hydroxide / walnut shell precursor mixed powder in a rotary furnace for activation treatment under a nitrogen atmosphere at a gas flow rate of 1 L / min at a temperature of 600 DEG C for 12 hours, so as to decompose the sodium hydroxide and reduce the sodium hydroxide by carbon in the walnut shell precursor, and at the same time, to etch the walnut shell precursor, so that the walnut shell precursor forms a pore structure, and a pre-sodium porous carbon material is obtained.

[0068] The fourth step is to continue to introduce nitrogen gas at a gas flow rate of 0.2 L / min and methane at a gas flow rate of 0.8 L / min into the rotary furnace at a volume ratio of nitrogen gas to methane of 1:4, and to carry out coating on the pre-sodium porous carbon material by chemical vapor deposition at a temperature of 800 DEG C for 6 hours, so as to obtain a pre-sodium sodium-ion battery negative electrode material.

[0069] The assembly and test of the button-type half cell are the same as those of Example 1.

[0070] Example 4

[0071] The first step is to carry out high-temperature carbonization treatment on the walnut shell under a nitrogen atmosphere at a temperature of 900 DEG C for 6 hours, so as to obtain a walnut shell precursor.

[0072] The second step is to mix and grind 100 g of the walnut shell precursor and 100 g of sodium hydroxide, so as to obtain a sodium hydroxide / walnut shell precursor mixed powder.

[0073] Third step, under the nitrogen atmosphere with the gas flow of 1 L / min, the sodium hydroxide / walnut shell precursor mixed powder is placed in the rotary furnace for activation treatment, at the temperature of 800℃, the heat preservation is 12 hours, so that the sodium hydroxide is decomposed and reduced by the carbon in the walnut shell precursor, at the same time, the walnut shell precursor is etched, so that the walnut shell precursor forms the pore structure, and the pre-sodium porous carbon material is obtained.

[0074] Fourth step, according to the volume ratio of nitrogen and methane of 1:4, the nitrogen is continuously introduced into the rotary furnace at the gas flow of 0.2 L / min, and the methane is introduced at the gas flow of 0.8 L / min, at the temperature of 800℃, the heat preservation is 6 hours, the pre-sodium porous carbon material is coated by chemical vapor deposition, and the pre-sodium sodium ion battery negative electrode material is obtained.

[0075] The assembly and test of the button half cell are the same as those of Example 1.

[0076] Example 5

[0077] First step, under the nitrogen atmosphere, the temperature is 900℃, the heat preservation is 6 hours, the walnut shell is treated by high-temperature carbonization, and the walnut shell precursor is obtained.

[0078] Second step, 100g of the walnut shell precursor and 300g of sodium hydroxide are weighed and mixed and ground to obtain a sodium hydroxide / walnut shell precursor mixed powder.

[0079] Third step, under the nitrogen atmosphere with the gas flow of 1 L / min, the sodium hydroxide / walnut shell precursor mixed powder is placed in the rotary furnace for activation treatment, at the temperature of 800℃, the heat preservation is 6 hours, so that the sodium hydroxide is decomposed and reduced by the carbon in the walnut shell precursor, at the same time, the walnut shell precursor is etched, so that the walnut shell precursor forms the pore structure, and the pre-sodium porous carbon material is obtained.

[0080] Fourth step, according to the volume ratio of nitrogen and methane of 1:4, the nitrogen is continuously introduced into the rotary furnace at the gas flow of 0.2 L / min, and the methane is introduced at the gas flow of 0.8 L / min, at the temperature of 900℃, the heat preservation is 1 hour, the pre-sodium porous carbon material is coated by chemical vapor deposition, and the pre-sodium sodium ion battery negative electrode material is obtained.

[0081] The assembly and test of the button half cell are the same as those of Example 1.

[0082] Comparative Example 1

[0083] First step, under the nitrogen atmosphere, the temperature is 900℃, the heat preservation is 6 hours, the walnut shell is treated by high-temperature carbonization, and the walnut shell precursor is obtained.

[0084] Second step, 100g of walnut shell precursor and 300g of sodium hydroxide are mixed and ground to obtain sodium hydroxide / walnut shell precursor mixed powder.

[0085] Third step, under the nitrogen atmosphere with a gas flow of 1L / min, the sodium hydroxide / walnut shell precursor mixed powder is placed in a rotary furnace for activation treatment, at a temperature of 800℃, for 6 hours, so that the sodium hydroxide is decomposed and reduced by carbon in the walnut shell precursor, at the same time, the walnut shell precursor is etched to form a pore structure, and a pre-sodium porous carbon material is obtained.

[0086] However, after the pre-sodium porous carbon material is taken out, it will spontaneously ignite, so that the assembly and test of the button-type half cell cannot be carried out.

[0087] Comparative Example 2

[0088] First step, under the nitrogen atmosphere, the walnut shell is subjected to high-temperature carbonization treatment at a temperature of 900℃ for 6 hours to obtain a walnut shell precursor.

[0089] Second step, 100g of walnut shell precursor and 20g of sodium hydroxide are mixed and ground to obtain sodium hydroxide / walnut shell precursor mixed powder.

[0090] Third step, under the nitrogen atmosphere with a gas flow of 1L / min, the sodium hydroxide / walnut shell precursor mixed powder is placed in a rotary furnace for activation treatment, at a temperature of 800℃, for 6 hours, so that the sodium hydroxide is decomposed and reduced by carbon in the walnut shell precursor, at the same time, the walnut shell precursor is etched to form a pore structure, and a pre-sodium porous carbon material is obtained.

[0091] Then, the prepared pre-sodium porous carbon material is used for the assembly and test of the button-type half cell, and the assembly and test are the same as those of Example 1.

[0092] According to Figure 2 It can be known that the charge-discharge curve of the material prepared by the present application is normal compared with Comparative Example 2, which indicates that the pre-sodium method does not produce other side reactions.

[0093] According to Figure 3The initial efficiency of the comparative example 2 is only 43.28%. This is because the preparation method of the application successfully realizes the pre-sodium effect of the pre-sodium sodium ion battery negative electrode material, and improves the low initial efficiency problem of the sodium ion battery negative electrode material. Although the pre-sodium porous carbon material can be successfully prepared by reducing the ratio of sodium hydroxide to walnut shell precursor in the comparative example 2, the active sodium in the pore is not protected by the chemical vapor deposition process, resulting in poor pre-sodium effect, so that the initial efficiency of the button half battery assembled by using the material is not improved, and remains low.

[0094] According to Figure 4 It can be seen that due to the pre-sodium effect, the initial voltage of examples 1-5 is lower than that of comparative example 2, which is one of the signs of successful pre-sodium, which shows that the increase of sodium content in the battery system can effectively make up for the consumption of SEI film formation and irreversible adsorption of sodium in the material, therefore, the preparation method of the application is an effective method to improve the initial efficiency.

[0095] Example 6

[0096] In the first step, the chitosan is subjected to high-temperature carbonization treatment under an argon atmosphere at a temperature of 800°C for 12 hours to obtain a chitosan precursor.

[0097] In the second step, 100g of the chitosan precursor and 1000g of sodium hydroxide are weighed and mixed and ground to obtain a sodium hydroxide / chitosan precursor mixed powder.

[0098] In the third step, the sodium hydroxide / chitosan precursor mixed powder is placed in a rotary furnace for activation treatment under an argon atmosphere with a gas flow of 0.8L / min at a temperature of 500°C for 12 hours, so that the sodium hydroxide is decomposed and reduced by the carbon in the chitosan precursor, and at the same time, the chitosan precursor is etched to form a pore structure, thereby obtaining a pre-sodium porous carbon material.

[0099] In the fourth step, argon is continuously introduced into the rotary furnace at a gas flow rate of 0.2L / min and ethylene is introduced at a gas flow rate of 0.6L / min at a temperature of 500°C for 12 hours according to the volume ratio of argon to ethylene of 1:3, and the pre-sodium porous carbon material is coated by chemical vapor deposition to obtain a pre-sodium sodium ion battery negative electrode material.

[0100] Example 7

[0101] In the first step, the graphene is subjected to high-temperature carbonization treatment under a helium atmosphere at a temperature of 1000°C for 6 hours to obtain a graphene precursor.

[0102] Second step, take 100g of graphene precursor and 50g of sodium hydroxide and mix and grind to obtain sodium hydroxide / graphene precursor mixed powder.

[0103] Third step, under the atmosphere of helium gas with a gas flow of 1.2L / min, the sodium hydroxide / graphene precursor mixed powder is placed in a rotary furnace for activation treatment, at a temperature of 1200℃, and heat preservation for 1 hour, so that the sodium hydroxide is decomposed and reduced by carbon in the graphene precursor, at the same time, the graphene precursor is etched to form a pore structure, and a pre-sodium porous carbon material is obtained.

[0104] Fourth step, according to the volume ratio of helium to propylene of 3:1, continue to pass helium into the rotary furnace at a gas flow of 0.6L / min, and pass propylene at a gas flow of 0.2L / min, at a temperature of 700℃, and heat preservation for 8 hours, the pre-sodium porous carbon material is coated by chemical vapor deposition to obtain a pre-sodium sodium ion battery negative electrode material.

[0105] Example 8

[0106] First step, under the atmosphere of helium gas, the temperature is 1500℃, and heat preservation for 3 hours, the phenolic resin is high-temperature carbonized to obtain a phenolic resin precursor.

[0107] Second step, take 100g of phenolic resin precursor and 25g of sodium hydroxide and mix and grind to obtain sodium hydroxide / phenolic resin precursor mixed powder.

[0108] Third step, under the atmosphere of helium gas with a gas flow of 0.9L / min, the sodium hydroxide / phenolic resin precursor mixed powder is placed in a rotary furnace for activation treatment, at a temperature of 1000℃, and heat preservation for 5 hours, so that the sodium hydroxide is decomposed and reduced by carbon in the phenolic resin precursor, at the same time, the phenolic resin precursor is etched to form a pore structure, and a pre-sodium porous carbon material is obtained.

[0109] Fourth step, according to the volume ratio of helium to acetylene of 1:5, continue to pass helium into the rotary furnace at a gas flow of 0.2L / min, and pass acetylene at a gas flow of 1L / min, at a temperature of 850℃, and heat preservation for 9 hours, the pre-sodium porous carbon material is coated by chemical vapor deposition to obtain a pre-sodium sodium ion battery negative electrode material.

[0110] Example 9

[0111] First step, under the atmosphere of argon gas, the temperature is 950℃, and heat preservation for 8 hours, the lignin is high-temperature carbonized to obtain a lignin precursor.

[0112] Second step, 100g of lignin precursor and 20g of sodium hydroxide are mixed and ground to obtain sodium hydroxide / lignin precursor mixed powder.

[0113] Third step, the sodium hydroxide / lignin precursor mixed powder is placed in a rotary furnace for activation treatment under the nitrogen atmosphere with a gas flow of 1.1L / min, and is kept at a temperature of 900℃ for 8 hours, so that the sodium hydroxide is decomposed and reduced by the carbon in the lignin precursor, and at the same time, the lignin precursor is etched to form a pore structure, and a pre-sodium porous carbon material is obtained.

[0114] Fourth step, according to the volume ratio of argon to carbon monoxide of 4:1, argon is introduced into the rotary furnace at a gas flow of 0.8L / min, and carbon monoxide is introduced at a gas flow of 0.2L / min, and the pre-sodium porous carbon material is coated by chemical vapor deposition at a temperature of 600℃ for 10 hours, and a pre-sodium sodium ion battery negative electrode material is obtained.

[0115] The above specific embodiments further illustrate the purpose, technical solutions and beneficial effects of the present application. It should be understood that the above description is only a specific embodiment of the present application and is not used to limit the protection scope of the present application. Any modification, equivalent replacement, improvement, etc. within the spirit and principle of the present application should be included in the protection scope of the present application.

Claims

1. A method for preparing a pre-sodiated sodium-ion battery anode material, characterized in that, The preparation method comprises: mixing and grinding a carbon precursor and sodium hydroxide according to a certain mass ratio to obtain a mixed powder; placing the mixed powder in a rotary furnace under an inert atmosphere to perform activation treatment, so that the sodium hydroxide is decomposed and reduced by carbon in the carbon precursor, and the carbon precursor is etched to form a pore structure, thereby obtaining a pre-sodium porous carbon material; coating the pre-sodium porous carbon material by chemical vapor deposition in the rotary furnace to obtain a pre-sodiumized sodium ion battery negative electrode material.

2. The production method according to claim 1, characterized by, The mass ratio of the carbon precursor to sodium hydroxide is 1:10-5:

1.

3. The production method according to claim 1, characterized by, The temperature of the activation treatment is 500-1200°C, and the activation treatment time is 1-12 hours.

4. The method of claim 1, wherein, The carbon precursor includes one or more of coconut skin, nut shell, kelp, grapefruit skin, lotus root, eggshell membrane, cork, coconut shell, straw, starch, renewable cotton, polyaniline, lignin, cellulose, hemicellulose, honeycomb coal, chitosan, pitch, phenolic resin, glucose, magnesium gluconate, polyvinylpyrrolidone, graphene oxide, graphene, xylose, epoxy resin, petroleum coke, or a product after high-temperature treatment of the above substances; wherein the high-temperature treatment temperature is 800-1800°C.

5. The preparation method according to claim 1, characterized in that The gas for chemical vapor deposition includes a carbon source gas and a protective gas; wherein the volume ratio of the carbon source gas to the protective gas is 1:5-5:

1.

6. The production method according to claim 5, wherein The carbon source gas is one or more of methane, acetylene, ethylene, propylene, or carbon monoxide; and the protective gas is one or more of nitrogen, helium, or argon.

7. The preparation method according to claim 1, characterized in that The conditions for chemical vapor deposition are: a deposition temperature of 500-900°C, and a deposition time of 0.5-12 hours.

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