Porous carbon material based on optimization of spray precursor liquid as well as preparation method and application of porous carbon material

Abstract

The invention relates to a porous carbon material based on spray precursor liquid optimization and a preparation method and application thereof. The preparation method comprises the following steps: adding a template raw material into a solvent, fully mixing, adding a carbon source material, and sanding in a sand mill; wherein the template raw material comprises nano silicon dioxide with the particle size of 3-10 nm; the diameter of the zirconium beads in the sand mill is 0.1-0.5 mm, the temperature in the sanding process is controlled to be 15-25 DEG C, and the sanding time is 3-5 hours; the solvent comprises ethanol; the carbon source material comprises a resin material and / or a biomass material; carrying out spray drying treatment on the spray precursor solution obtained by sanding to obtain a powder sample; in an inert atmosphere, carrying out segmented calcination on the powder sample to obtain a carbon / silicon dioxide compound; the step-by-step calcination comprises first-stage calcination at the temperature of 300 to 600 DEG C and second-stage calcination at the temperature of 700 to 1100 DEG C; and carrying out etching treatment on the carbon / silicon dioxide compound in an etching agent, cleaning and drying to obtain the porous carbon material.

Description

Technical Field

[0001] This invention relates to the field of new energy materials technology, and in particular to porous carbon materials optimized based on spray precursor fluids, their preparation methods, and applications. Background Technology

[0002] With the rapid development of new energy technologies, porous carbon materials have attracted widespread attention due to their unique physicochemical properties. Porous carbon materials possess high specific surface area, good electrical conductivity, and excellent energy storage capacity, making them widely used in lithium-ion batteries, supercapacitors, catalyst supports, and gas adsorption. In lithium-ion batteries, porous carbon, as a negative electrode material, not only improves the battery's energy density but also enhances its cycle stability and charge-discharge performance. In supercapacitors, the high specific surface area of ​​porous carbon materials can significantly improve energy and power density. Furthermore, porous carbon can also serve as a catalyst support, providing numerous active sites and improving the efficiency and selectivity of catalytic reactions. Therefore, the research and development of high-performance porous carbon materials is particularly important.

[0003] The preparation methods for porous carbon materials mainly include physical methods, chemical methods, and template methods. Physical methods, such as vapor deposition and carbonization, are generally simple to operate, but have limited control over the material's structure. Chemical methods, such as chemical vapor deposition (CVD) and hydrothermal synthesis, can precisely control the structure and properties of carbon materials, but are relatively expensive. Template methods are widely used in the preparation of porous carbon, with hard template methods and soft template methods being particularly common. Hard template methods use materials such as silica (SiO2) as templates to obtain relatively regular pore structures. However, although the silica hard template method has achieved certain results in the preparation of porous carbon, it still has some limitations in practical applications. The main problems faced by the hard template method in application include: poor dispersibility; silica particles have poor dispersibility in solution and are prone to agglomeration, resulting in an uneven precursor liquid during spray drying. This unevenness directly affects the pore structure and properties of the final porous carbon. Furthermore, due to the dispersion problem of the template, the pore structure of the final porous carbon material is often difficult to control precisely, leading to fluctuations in material properties and affecting its reliability in practical applications. Summary of the Invention

[0004] The purpose of this invention is to address the shortcomings of existing technologies by providing a porous carbon material optimized based on spray precursor fluid, its preparation method, and its application.

[0005] To achieve the above objectives, in a first aspect, the present invention provides a method for preparing porous carbon materials optimized based on spray precursor fluids, comprising:

[0006] The template material is added to a solvent and thoroughly mixed, then a carbon source material is added, and the mixture is sand-milled. The template material comprises nano-silica with a particle size of 3-10 nm. The zirconium beads in the sand mill have a diameter of 0.1-0.5 mm. The temperature during sand milling is controlled at 15-25℃, and the sand milling time is 3-5 hours. The solvent includes ethanol. The carbon source material includes resin-based materials and / or biomass-based materials.

[0007] The spray precursor solution obtained by sand milling was spray dried to obtain a powder sample;

[0008] The powder sample was subjected to segmented calcination under an inert atmosphere to obtain a carbon / silica composite; the segmented calcination included: a first stage calcination at 300-600℃ and a second stage calcination at 700-1100℃.

[0009] The carbon / silica composite was etched in an etchant, and the porous carbon material was obtained after cleaning and drying.

[0010] Preferably, the biomass materials include one or more of the following: coconut shell, straw, rice husk, wood, bamboo, sugarcane bagasse, and nut shells;

[0011] The resin materials include one or more of the following: furan resin, urea-formaldehyde resin, pyrimidine resin, phenolic resin, epoxy resin, polyoxymethylene acrylate resin, and polyacrylonitrile.

[0012] Preferably, the mass ratio of the carbon source material to the template raw material is 0.8:1 to 1.2:1.

[0013] Preferably, the thorough mixing specifically includes stirring; the stirring speed is 400-1000 rpm, the stirring temperature is 25-40℃, and the stirring time is 1-10 h.

[0014] Preferably, the temperature control during the sand milling process is specifically achieved through the on / off state and flow rate control of the circulating cooling water.

[0015] Preferably, in the spray drying process, the inlet temperature is 150-180℃, the outlet temperature is 70-90℃, and the atomizer frequency is 220Hz.

[0016] Preferably, the equipment for segmented calcination includes one or more of the following: tube furnace, atmosphere furnace, rotary furnace, and box furnace;

[0017] The calcination time in the first stage is 1-4 hours, and the heating rate is 1-5℃ / min;

[0018] The second stage of calcination lasts for 1-4 hours, with a heating rate of 1-5℃ / min.

[0019] The inert atmosphere is an argon atmosphere or a nitrogen atmosphere.

[0020] Preferably, the etching agent comprises one or more of HCl, H2SO4, HNO3, HF and NaOH with a solution concentration of 0.1-5 mol / L;

[0021] The etching process takes 1-8 hours and is carried out at a temperature of 25-60°C.

[0022] The cleaning is a water wash;

[0023] The drying equipment includes one or more of the following: a forced-air drying oven, a vacuum drying oven, a tunnel drying oven, and a rotary dryer;

[0024] The drying temperature is 70-110℃, and the time is 6-20h.

[0025] Secondly, embodiments of the present invention provide a porous carbon material prepared by the preparation method described in the first aspect above.

[0026] Thirdly, embodiments of the present invention provide a lithium-ion battery, wherein the negative electrode material of the lithium-ion battery includes the porous carbon material described in the second aspect above.

[0027] The method for preparing porous carbon materials based on optimized spray precursor liquid provided in this invention improves the influence of the spray precursor liquid preparation process on the properties of the precursor solution by optimizing key parameters such as the particle size of the template raw material, milling time, temperature control, and zirconium bead size. This significantly improves the dispersibility of the precursor liquid, thereby enhancing the uniformity and controllability of the pore structure of the porous carbon during spray drying. The resulting porous carbon material not only exhibits excellent electrical conductivity but also has a high proportion of mesopores in the 2-10 nm range, laying the foundation for the subsequent preparation of high-performance lithium-ion battery anode materials. Attached Figure Description

[0028] Figure 1 This is a flowchart of a method for preparing porous carbon materials based on spray precursor fluid optimization provided in an embodiment of the present invention;

[0029] Figure 2 A scanning electron microscope (SEM) image of the porous carbon material prepared in Example 1 of this invention;

[0030] Figure 3 This is a pore size distribution diagram of the porous carbon material prepared in Example 1 of the present invention;

[0031] Figure 4 This is a pore size distribution diagram of the porous carbon material prepared in Comparative Example 1 of the present invention. Detailed Implementation

[0032] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments.

[0033] This invention provides a porous carbon material, its preparation method, and its application. The method is based on optimizing the spray precursor fluid to obtain a porous carbon material with higher electrical conductivity and a larger specific surface area.

[0034] Figure 1 This is a flowchart of the preparation method of porous carbon materials provided in the embodiments of the present invention. The following is in conjunction with... Figure 1 First, the preparation method provided by the present invention will be described.

[0035] The preparation method of the present invention includes:

[0036] Step 110: After thoroughly mixing the template material in the solvent, add the carbon source material and then grind it in a sand mill.

[0037] Specifically, the template material includes nano-silica with a particle size of 3-10nm; the solvent includes ethanol; thorough mixing specifically includes stirring; the stirring speed is 400-1000rpm, the stirring temperature is 25-40℃, and the stirring time is 1-10h.

[0038] Carbon source materials include resin materials and / or biomass materials; among which, resin materials include one or more of the following: furan resin, urea-formaldehyde resin, pyrimidine resin, phenolic resin, epoxy resin, polyoxymethylene acrylate resin, and polyacrylonitrile; biomass materials include one or more of the following: coconut shell, straw, rice husk, wood, bamboo, sugarcane bagasse, and nut shells.

[0039] The mass ratio of carbon source material to template raw material is 0.8:1 to 1.2:1.

[0040] The diameter of the zirconium beads in the sand mill is 0.1-0.5mm; during the sand milling process, the temperature is controlled by the opening and closing status and flow rate of the circulating cooling water, and the specific temperature is controlled at 15-25℃; the sand milling time is 3-5 hours.

[0041] In this step, the template material is first added to the solvent and thoroughly mixed before the carbon source material is added and milled. This method has certain technical advantages compared to adding the template material and carbon source material together to the solvent for direct milling. The template material (nano-silica) has a small particle size (3-10nm) and is prone to agglomeration. Thoroughly mixing and dispersing it separately in the solvent allows for better separation of the nanoparticles, preventing them from agglomerating. This is equivalent to a pre-mixing step, ensuring uniform dispersion of the template material. This facilitates uniform contact with the carbon source material and improves the uniformity of both during milling, resulting in a more uniform precursor liquid and contributing to the formation of a more uniform pore structure.

[0042] Milling effectively improves the uniformity of the precursor liquid, reduces agglomeration, and allows the template material to more uniformly coat the carbon source material. The optimized precursor liquid exhibits enhanced dispersibility, laying the foundation for subsequent spray drying to obtain porous carbon materials with highly uniform pore structures.

[0043] Step 120: Spray dry the spray precursor solution obtained by sand milling to obtain a powder sample.

[0044] During spray drying, the inlet temperature is 150-180℃, the outlet temperature is 70-90℃, and the atomizer frequency is 220Hz.

[0045] Spray drying can rapidly transform liquids into fine powder particles while preserving the uniform distribution of the template material. This process helps obtain a precursor with an ideal porous structure, resulting in a more uniform microstructure in the final carbon material, which is beneficial for the uniform distribution of pores.

[0046] Step 130: Under an inert atmosphere, the powder sample is calcined in stages to obtain a carbon / silica composite.

[0047] The inert atmosphere is either argon or nitrogen.

[0048] Equipment for segmented calcination includes one or more of the following: tubular furnace, atmosphere furnace, rotary furnace, and box furnace.

[0049] The segmented calcination includes: a first stage of calcination at 300-600℃ and a second stage of calcination at 700-1100℃; wherein the first stage of calcination lasts for 1-4 hours with a heating rate of 1-5℃ / min; and the second stage of calcination lasts for 1-4 hours with a heating rate of 1-5℃ / min.

[0050] This invention employs segmented calcination to achieve the ordered transformation of carbon materials. The first stage involves low-temperature calcination to remove some precursor components, while the second stage involves high-temperature calcination to enhance the crystallinity and conductivity of the carbon material, ultimately forming a carbon / silica composite. By setting the segmented temperatures and using a slow heating rate (1-5℃ / min), the pore structure, specific surface area, and electrical conductivity of the porous carbon material can be controlled.

[0051] Step 140: The carbon / silica composite is etched in an etchant, and after cleaning and drying, a porous carbon material is obtained.

[0052] Specifically, the etching agent includes one or more of HCl, H2SO4, HNO3, HF, and NaOH, with a solution concentration of 0.1-5 mol / L; more preferably, NaOH. The etching treatment time is 1-8 hours, and the etching treatment temperature is 25-60℃.

[0053] The washing process involves water washing. Drying equipment includes one or more of the following: forced-air drying oven, vacuum drying oven, tunnel drying oven, and rotary dryer; the drying temperature is 70-110℃, and the time is 6-20 hours.

[0054] After etching away the template material, a uniformly distributed pore structure is left behind, resulting in a high specific surface area for the final porous carbon material. Furthermore, by controlling the particle size of the template material, optimizing the milling time and temperature, and adjusting the size of the zirconium beads, the final material achieves a high mesopore content between 2 and 10 nm. This porous structure is beneficial for improving the material's electrical conductivity, laying the foundation for its application in high-performance lithium-ion battery anode materials.

[0055] The porous carbon material prepared by this invention can be applied to various energy storage devices. In particular, when it is used as a negative electrode material for lithium-ion batteries, it can significantly improve the cycle performance of lithium-ion batteries due to its high specific surface area, electrical conductivity, and pore structure characteristics.

[0056] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this invention, and not all of them. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0057] Example 1

[0058] This embodiment provides a method for preparing porous carbon materials, the specific process of which is as follows.

[0059] S1. According to the mass ratio of nano-silica to phenolic resin of 1:1, add nano-silica with a particle size of 3-10nm to a stirring tank containing ethanol solution and mix evenly. Then add phenolic resin to the above solution and continue stirring. At the same time, turn on the sand mill and select 0.1mm zirconium beads in the sand mill and sand mill for 3 hours. During this process, turn on the cooling circulating water and control the internal temperature of the sand mill at 20℃ to obtain the spray precursor solution.

[0060] S2. The spray precursor solution obtained in S1 is subjected to closed-loop spray drying. The inlet temperature is set to 165℃, the outlet temperature to 85℃, the atomizer frequency to 220Hz, and the feed flow rate to 3.5mL / min to prepare silica / carbon precursor composite powder.

[0061] S3. The silica / carbon precursor composite powder obtained in S2 is heated from room temperature to 400°C in a nitrogen atmosphere furnace at a heating rate of 2°C / min and held for 1 hour. Then, it is heated to 800°C at a heating rate of 5°C / min and held for 2 hours to obtain the silica / carbon composite material.

[0062] S4. The obtained silica / carbon composite material was etched using a 1 mol / L NaOH solution, with a mass ratio of etching solution to material of 4:1. After immersing the silica / carbon composite material at 50°C for 8 hours, it was washed and discharged, and then dried in an oven at 85°C for 10 hours to obtain porous carbon material.

[0063] Figure 2 This is a scanning electron microscope (SEM) image of the porous carbon material prepared in Example 1 of the present invention.

[0064] Example 2

[0065] This embodiment provides a method for preparing porous carbon materials, the specific process of which is as follows.

[0066] S1. According to the mass ratio of nano-silica to coconut shell of 1:1, add nano-silica with a particle size of 3-10nm to a stirring tank containing ethanol solution and mix evenly. Then add phenolic resin to the above solution and continue stirring. At the same time, turn on the sand mill and select 0.1mm zirconium beads in the sand mill and sand mill for 3 hours. During this process, turn on the cooling circulating water and control the internal temperature of the sand mill at 20℃ to obtain the spray precursor solution.

[0067] S2. The spray precursor solution obtained in S1 is subjected to closed-loop spray drying. The inlet temperature is set to 165℃, the outlet temperature to 85℃, the atomizer frequency to 220Hz, and the feed flow rate to 3.5mL / min to prepare silica / carbon precursor composite powder.

[0068] S3. The silica / carbon precursor composite powder obtained in S2 is heated from room temperature to 400°C in a nitrogen atmosphere furnace at a heating rate of 2°C / min and held for 1 hour. Then, it is heated to 800°C at a heating rate of 5°C / min and held for 2 hours to obtain the silica / carbon composite material.

[0069] S4. The obtained silica / carbon composite material was etched using a 1 mol / L NaOH solution, with a mass ratio of etching solution to material of 4:1. After immersing the silica / carbon composite material at 50°C for 8 hours, it was washed and discharged, and then dried in an oven at 85°C for 10 hours to obtain porous carbon material.

[0070] Example 3

[0071] This embodiment provides a method for preparing porous carbon materials, the specific process of which is as follows.

[0072] S1. According to the mass ratio of nano-silica to phenolic resin of 0.8:1, nano-silica with a particle size of 3-10nm is added to a stirring tank containing ethanol solution and mixed evenly. Then, phenolic resin is added to the above solution and stirred continuously. At the same time, a sand mill is turned on, and 0.1mm zirconium beads are selected in the sand mill and sand milled for 3 hours. During this process, the cooling circulating water is turned on to control the internal temperature of the sand mill at 20℃, so as to obtain the spray precursor solution.

[0073] S2. The spray precursor solution obtained in S1 is subjected to closed-loop spray drying. The inlet temperature is set to 165℃, the outlet temperature to 85℃, the atomizer frequency to 220Hz, and the feed flow rate to 3.5mL / min to prepare silica / carbon precursor composite powder.

[0074] S3. The silica / carbon precursor composite powder obtained in S2 is heated from room temperature to 400°C in a nitrogen atmosphere furnace at a heating rate of 2°C / min and held for 1 hour. Then, it is heated to 800°C at a heating rate of 5°C / min and held for 2 hours to obtain the silica / carbon composite material.

[0075] S4. The obtained silica / carbon composite material was etched using a 1 mol / L NaOH solution, with a mass ratio of etching solution to material of 4:1. After immersing the silica / carbon composite material at 50°C for 8 hours, it was washed and discharged, and then dried in an oven at 85°C for 10 hours to obtain porous carbon material.

[0076] Example 4

[0077] This embodiment provides a method for preparing porous carbon materials, the specific process of which is as follows.

[0078] S1. According to the mass ratio of nano-silica to phenolic resin of 1.2:1, add nano-silica with a particle size of 3-10nm to a stirring tank containing ethanol solution and mix evenly. Then add phenolic resin to the above solution and continue stirring. At the same time, turn on the sand mill and select 0.1mm zirconium beads in the sand mill and sand mill for 3 hours. During this process, turn on the cooling circulating water and control the internal temperature of the sand mill at 20℃ to obtain the spray precursor solution.

[0079] S2. The spray precursor solution obtained in S1 is subjected to closed-loop spray drying. The inlet temperature is set to 165℃, the outlet temperature to 85℃, the atomizer frequency to 220Hz, and the feed flow rate to 3.5mL / min to prepare silica / carbon precursor composite powder.

[0080] S3. The silica / carbon precursor composite powder obtained in S2 is heated from room temperature to 400°C in a nitrogen atmosphere furnace at a heating rate of 2°C / min and held for 1 hour. Then, it is heated to 800°C at a heating rate of 5°C / min and held for 2 hours to obtain the silica / carbon composite material.

[0081] S4. The obtained silica / carbon composite material was etched using a 1 mol / L NaOH solution, with a mass ratio of etching solution to material of 4:1. After immersing the silica / carbon composite material at 50°C for 8 hours, it was washed and discharged, and then dried in an oven at 85°C for 10 hours to obtain porous carbon material.

[0082] Example 5

[0083] This embodiment provides a method for preparing porous carbon materials, the specific process of which is as follows.

[0084] S1. According to the mass ratio of nano-silica to phenolic resin of 1:1, nano-silica with a particle size of 3-10nm is added to a stirring tank containing ethanol solution and mixed evenly. Then, phenolic resin is added to the above solution and stirred continuously. At the same time, a sand mill is turned on, and 0.1mm zirconium beads are selected in the sand mill and sand milled for 5 hours. During this process, the cooling circulating water is turned on to control the internal temperature of the sand mill at 20℃, so as to obtain the spray precursor solution.

[0085] S2. The spray precursor solution obtained in S1 is subjected to closed-loop spray drying. The inlet temperature is set to 165℃, the outlet temperature to 85℃, the atomizer frequency to 220Hz, and the feed flow rate to 3.5mL / min to prepare silica / carbon precursor composite powder.

[0086] S3. The silica / carbon precursor composite powder obtained in S2 is heated from room temperature to 400°C in a nitrogen atmosphere furnace at a heating rate of 2°C / min and held for 1 hour. Then, it is heated to 800°C at a heating rate of 5°C / min and held for 2 hours to obtain the silica / carbon composite material.

[0087] S4. The obtained silica / carbon composite material was etched using a 1 mol / L NaOH solution, with a mass ratio of etching solution to material of 4:1. After immersing the silica / carbon composite material at 50°C for 8 hours, it was washed and discharged, and then dried in an oven at 85°C for 10 hours to obtain porous carbon material.

[0088] Example 6

[0089] This embodiment provides a method for preparing porous carbon materials, the specific process of which is as follows.

[0090] S1. According to the mass ratio of nano-silica to phenolic resin of 1:1, add nano-silica with a particle size of 3-10nm to a stirring tank containing ethanol solution and mix evenly. Then add phenolic resin to the above solution and continue stirring. At the same time, turn on the sand mill and select 0.5mm zirconium beads in the sand mill and sand mill for 3 hours. During this process, turn on the cooling circulating water and control the internal temperature of the sand mill at 20℃ to obtain the spray precursor solution.

[0091] S2. The spray precursor solution obtained in S1 is subjected to closed-loop spray drying. The inlet temperature is set to 165℃, the outlet temperature to 85℃, the atomizer frequency to 220Hz, and the feed flow rate to 3.5mL / min to prepare silica / carbon precursor composite powder.

[0092] S3. The silica / carbon precursor composite powder obtained in S2 is heated from room temperature to 400°C in a nitrogen atmosphere furnace at a heating rate of 2°C / min and held for 1 hour. Then, it is heated to 800°C at a heating rate of 5°C / min and held for 2 hours to obtain the silica / carbon composite material.

[0093] S4. The obtained silica / carbon composite material was etched using a 1 mol / L NaOH solution, with a mass ratio of etching solution to material of 4:1. After immersing the silica / carbon composite material at 50°C for 8 hours, it was washed and discharged, and then dried in an oven at 85°C for 10 hours to obtain porous carbon material.

[0094] The temperature, time, and proportions used in the preparation of the above embodiments are merely specific parameters used to implement the above embodiments of the present invention, and do not imply that the technical solution of the present invention is limited to the above parameters. The technical solution of the present invention can be implemented within the range of parameters already described in the overall description of the preparation method of the present invention.

[0095] Comparative Example 1

[0096] This comparative example provides a method for preparing porous carbon materials, the specific process of which is as follows.

[0097] S1. According to the mass ratio of nano-silica to phenolic resin of 1:1, take nano-silica with a particle size of 3-10nm and add it to a stirring tank containing ethanol solution and mix evenly. Then take phenolic resin and add it to the above solution. Continue stirring to obtain the spray precursor solution.

[0098] S2. The spray precursor solution obtained in S1 is subjected to closed-loop spray drying. The inlet temperature is set to 165℃, the outlet temperature to 85℃, the atomizer frequency to 220Hz, and the feed flow rate to 3.5mL / min to prepare silica / carbon precursor composite powder.

[0099] S3. The silica / carbon precursor composite powder obtained in S2 is heated from room temperature to 400°C in a nitrogen atmosphere furnace at a heating rate of 2°C / min and held for 1 hour. Then, it is heated to 800°C at a heating rate of 5°C / min and held for 2 hours to obtain the silica / carbon composite material.

[0100] S4. The obtained silica / carbon composite material was etched using a 1 mol / L NaOH solution, with a mass ratio of etching solution to material of 4:1. After immersing the silica / carbon composite material at 50°C for 8 hours, it was washed and discharged, and then dried in an oven at 85°C for 10 hours to obtain porous carbon material.

[0101] Comparative Example 2

[0102] This comparative example provides a method for preparing porous carbon materials, the specific process of which is as follows.

[0103] S1. According to the mass ratio of nano-silica to phenolic resin of 1:1, add nano-silica with a particle size of 3-10nm to a stirring tank containing ethanol solution and mix evenly. Then add phenolic resin to the above solution and continue stirring. At the same time, turn on the sand mill and select 0.1mm zirconium beads in the sand mill and sand mill for 3 hours. During this process, do not turn on the cooling circulating water. The internal temperature of the sand mill exceeds 60℃ during the sand milling process to obtain the spray precursor solution.

[0104] S2. The spray precursor solution obtained in S1 is subjected to closed-loop spray drying. The inlet temperature is set to 165℃, the outlet temperature to 85℃, the atomizer frequency to 220Hz, and the feed flow rate to 3.5mL / min to prepare silica / carbon precursor composite powder.

[0105] S3. The silica / carbon precursor composite powder obtained in S2 is heated from room temperature to 400°C in a nitrogen atmosphere furnace at a heating rate of 2°C / min and held for 1 hour. Then, it is heated to 800°C at a heating rate of 5°C / min and held for 2 hours to obtain the silica / carbon composite material.

[0106] S4. The obtained silica / carbon composite material was etched using a 1 mol / L NaOH solution, with a mass ratio of etching solution to material of 4:1. After immersing the silica / carbon composite material at 50°C for 8 hours, it was washed and discharged, and then dried in an oven at 85°C for 10 hours to obtain porous carbon material.

[0107] Comparative Example 3

[0108] This comparative example provides a method for preparing porous carbon materials, the specific process of which is as follows.

[0109] S1. According to the mass ratio of nano-silica to phenolic resin of 1:1, add nano-silica with a particle size of 3-10nm to a stirring tank containing ethanol solution and mix evenly. Then add phenolic resin to the above solution and continue stirring. At the same time, turn on the sand mill and select 1mm zirconium beads in the sand mill and sand mill for 3 hours. During this process, turn on the cooling circulating water and control the internal temperature of the sand mill at 20℃ to obtain the spray precursor solution.

[0110] S2. The spray precursor solution obtained in S1 is subjected to closed-loop spray drying. The inlet temperature is set to 165℃, the outlet temperature to 85℃, the atomizer frequency to 220Hz, and the feed flow rate to 3.5mL / min to prepare silica / carbon precursor composite powder.

[0111] S3. The silica / carbon precursor composite powder obtained in S2 is heated from room temperature to 400°C in a nitrogen atmosphere furnace at a heating rate of 2°C / min and held for 1 hour. Then, it is heated to 800°C at a heating rate of 5°C / min and held for 2 hours to obtain the silica / carbon composite material.

[0112] S4. The obtained silica / carbon composite material was etched using a 1 mol / L NaOH solution, with a mass ratio of etching solution to material of 4:1. After immersing the silica / carbon composite material at 50°C for 8 hours, it was washed and discharged, and then dried in an oven at 85°C for 10 hours to obtain porous carbon material.

[0113] Comparative Example 4

[0114] This comparative example provides a method for preparing porous carbon materials, the specific process of which is as follows.

[0115] S1. According to the mass ratio of nano-silica to phenolic resin of 1:1, add nano-silica with a particle size of 3-10nm to a stirring tank containing ethanol solution and mix evenly. Then add phenolic resin to the above solution and continue stirring. At the same time, turn on the sand mill and select 0.1mm zirconium beads in the sand mill and sand mill for 1 hour. During this process, turn on the cooling circulating water and control the internal temperature of the sand mill at 20℃ to obtain the spray precursor solution.

[0116] S2. The spray precursor solution obtained in S1 is subjected to closed-loop spray drying. The inlet temperature is set to 165℃, the outlet temperature to 85℃, the atomizer frequency to 220Hz, and the feed flow rate to 3.5mL / min to prepare silica / carbon precursor composite powder.

[0117] S3. The silica / carbon precursor composite powder obtained in S2 is heated from room temperature to 400°C in a nitrogen atmosphere furnace at a heating rate of 2°C / min and held for 1 hour. Then, it is heated to 800°C at a heating rate of 5°C / min and held for 2 hours to obtain the silica / carbon composite material.

[0118] S4. The obtained silica / carbon composite material was etched using a 1 mol / L NaOH solution, with a mass ratio of etching solution to material of 4:1. After immersing the silica / carbon composite material at 50°C for 8 hours, it was washed and discharged, and then dried in an oven at 85°C for 10 hours to obtain porous carbon material.

[0119] The electrical conductivity and pore size distribution of the porous carbon materials in Examples 1-6 and Comparative Examples 1-4 were tested. The electrical conductivity was measured and calculated using the four-probe method; the pore size distribution was analyzed by measuring the specific surface area (BET) using a gas adsorption analyzer (Quantachrom-IQ2-XR). The specific results are shown in Table 1.

[0120] sample Electrical conductivity (S / cm) <![CDATA[Specific surface area (m 2 / g)]]> Aperture (nm) <![CDATA[Pore volume (cm 3 / g)]]> Example 1 21.5 1310 3.5 1.21 Example 2 23.7 1235 4.2 1.23 Example 3 22.5 1243 3.9 1.29 Example 4 19.3 1520 4.5 1.27 Example 5 18.8 1550 3.3 1.22 Example 6 20.5 1210 4.3 1.28 Comparative Example 1 8.5 957 6.11 1.48 Comparative Example 2 9.3 1105 5.84 1.46 Comparative Example 3 7.9 1070 5.9 1.43 Comparative Example 4 8.8 1123 5.73 1.39

[0121] Table 1

[0122] A comparison of the data from Examples 1-6 and Comparative Examples 1-4 in Table 1 shows that by adjusting the milling time, cooling water usage, and zirconium bead size during milling, the electrical conductivity and specific surface area of ​​the obtained porous carbon materials were significantly improved. The low electrical conductivity of the materials in Comparative Examples 1-4 is related to their excessively high pore volume. Furthermore, the excessively high mesopore size also leads to structural instability of the porous carbon mesopores, causing the electrical contact between electrons and ions to break down, resulting in a decrease in electrical conductivity. Figure 3 This is a pore size distribution diagram of the porous carbon material prepared in Example 1 of the present invention; Figure 4 This is a pore size distribution diagram of the porous carbon material prepared in Comparative Example 1 of this invention. (From Table 1...) Figure 3 and Figure 4 As can be seen, the pore size in Example 1 is relatively concentrated, thanks to the improved uniformity of the spray-dried precursor liquid. Specifically, a longer milling time can improve the dispersibility of the precursor liquid; maintaining the temperature of the precursor liquid during milling can prevent the nano-silica from gelling due to overheating; and small milling zirconium beads can further disperse agglomerated particles. In summary, thanks to the optimized control of the above process parameters, the uniformity of pore size in the preparation of mesoporous carbon using the spray-drying-assisted nano-silica hard template method has been improved, while simultaneously increasing the material's electrical conductivity, laying the foundation for future applications in catalysis, new energy, and other fields.

[0123] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for preparing porous carbon materials optimized based on spray precursor fluids, characterized in that, The preparation method includes: The template material is added to a solvent and thoroughly mixed, then a carbon source material is added, and the mixture is sand-milled. The template material comprises nano-silica with a particle size of 3-10 nm. The zirconium beads in the sand mill have a diameter of 0.1-0.5 mm. The temperature during sand milling is controlled at 15-25℃, and the sand milling time is 3-5 hours. The solvent includes ethanol. The carbon source material includes resin-based materials and / or biomass-based materials. The spray precursor solution obtained by sand milling was spray dried to obtain a powder sample; The powder sample was subjected to segmented calcination under an inert atmosphere to obtain a carbon / silica composite; the segmented calcination included: a first stage calcination at 300-600℃ and a second stage calcination at 700-1100℃. The carbon / silica composite was etched in an etchant, and the porous carbon material was obtained after cleaning and drying.

2. The preparation method according to claim 1, characterized in that, The biomass materials include one or more of the following: coconut shells, straw, rice husks, wood, bamboo, sugarcane bagasse, and nut shells; The resin materials include one or more of the following: furan resin, urea-formaldehyde resin, pyrimidine resin, phenolic resin, epoxy resin, polyoxymethylene acrylate resin, and polyacrylonitrile.

3. The preparation method according to claim 1, characterized in that, The mass ratio of the carbon source material to the template raw material is 0.8:1 to 1.2:

1.

4. The preparation method according to claim 1, characterized in that, The thorough mixing specifically includes stirring; the stirring speed is 400-1000 rpm, the stirring temperature is 25-40℃, and the stirring time is 1-10 h.

5. The preparation method according to claim 1, characterized in that, Temperature control during the grinding process is specifically achieved through the on / off state and flow rate control of the circulating cooling water.

6. The preparation method according to claim 1, characterized in that, In the spray drying process, the inlet temperature is 150-180℃, the outlet temperature is 70-90℃, and the atomizer frequency is 220Hz.

7. The preparation method according to claim 1, characterized in that, The equipment for segmented calcination includes one or more of the following: tube furnace, atmosphere furnace, rotary furnace, and box furnace; The calcination time in the first stage is 1-4 hours, and the heating rate is 1-5℃ / min; The second stage of calcination lasts for 1-4 hours, with a heating rate of 1-5℃ / min. The inert atmosphere is an argon atmosphere or a nitrogen atmosphere.

8. The preparation method according to claim 1, characterized in that, The etching agent includes one or more of HCl, H2SO4, HNO3, HF and NaOH with a solution concentration of 0.1-5 mol / L; The etching process takes 1-8 hours and is carried out at a temperature of 25-60°C. The cleaning is a water wash; The drying equipment includes one or more of the following: a forced-air drying oven, a vacuum drying oven, a tunnel drying oven, and a rotary dryer; The drying temperature is 70-110℃, and the time is 6-20h.

9. A porous carbon material prepared by any one of the preparation methods described in claims 1-8.

10. A lithium-ion battery, characterized in that, The negative electrode material of the lithium-ion battery includes the porous carbon material described in claim 9.

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