A method for preparing biomass N, P, S multi-element doped graphitized carbon material

Abstract

The present invention provides a method for preparing a biomass N, P, and S multi-element doped graphitized carbon material, comprising the following steps: 1) uniformly mixing ferrocenecarboxylic acid, an organic solvent, 4-dimethylaminopyridine (DMAP), and alkali-activated biomass powder under ice bath conditions, dropwise adding a dicyclohexylcarbodiimide (DCC) solution, reacting under stirring conditions after the addition, filtering after the reaction, washing, and drying to obtain a modified biomass powder; and 2) uniformly mixing the modified biomass powder, humic acid, organic resin microspheres, and an alkali solution, drying for a first time, carbonizing, cooling, rinsing, drying for a second time, graphitizing, cooling, acid washing, washing with water, and drying for a third time to obtain the biomass graphitized carbon material. The biomass graphitized carbon material can be applied to lead-carbon batteries to improve cycle life and hydrogen evolution inhibition.

Description

Technical Field

[0001] The invention belongs to the technical field of biomass graphitized carbon materials, and in particular relates to a method for preparing a biomass N, P, S multi-element doped graphitized carbon material. Background Art

[0002] Lead-carbon batteries are a type of capacitive lead-acid battery, a technology evolved from traditional lead-acid batteries. They combine lead and carbon materials in the lead-acid battery's negative electrode. They have a long cycle life under high-rate charge and discharge conditions in partial states of charge, and show promising application prospects in energy storage and hybrid vehicles. Lead-carbon batteries are categorized as internally parallel and internally mixed based on the configuration of the negative electrode. The internally parallel type connects the lead and carbon negative electrodes in parallel in a specific manner, which is then combined with a PbO2 positive electrode plate to form a single battery cell. The internally mixed type adds carbon material as an additive to the negative electrode lead paste at a specific mass fraction or method, and produces the lead-carbon negative electrode plate according to conventional manufacturing processes. Due to cost and process operability, the internally mixed type has received more widespread attention.

[0003] Carbon materials used in lead-carbon batteries include high-purity graphite, high-surface-area activated carbon, carbon nanotubes, acetylene black, and graphene. Their mechanisms of action are believed to primarily include the following: conductive mechanism, steric mechanism, balanced charging mechanism, and capacitance mechanism. The main raw materials for preparing carbon materials include coal, petroleum, and petroleum derivatives. With humanity's continuous transformation and utilization of the natural environment, as well as social progress and economic development, the world is facing a serious energy crisis. Because biomass carbon materials are widely available and renewable, the use of biomass to prepare carbon materials for use in lead-carbon batteries is a current research hotspot. For example, patent CN115367750B discloses a biomass porous carbon material, its preparation method, and its application in lead-acid batteries, and patent CN105958076B discloses a modified carbon material, its preparation method, negative lead paste, plates, and lead-carbon batteries.

[0004] Biomass carbon materials are also often used as additives in the form of internal mixing. They can not only slow the accumulation and growth of lead sulfate crystals and inhibit the irreversible sulfation of the negative electrode, but can also reduce the hydrogen evolution overpotential caused by the addition of carbon materials through the above-mentioned technologies such as removing lignin or doping with high hydrogen evolution overpotential metal salts, and delay the hydrogen evolution reaction of the negative plate. However, compared with petroleum-based and coal-based carbon materials, biomass carbon materials are derived from biomass, such as straw and wood. These materials have complex chemical structures, cellular structures, and diverse chemical compositions. As a result, carbon materials prepared from biomass have poor conductivity and more unstable charge and discharge performance of lead-carbon batteries.

[0005] Therefore, it is necessary to use biomass to develop a carbon material that can not only slow down the accumulation and growth of lead sulfate crystals, but also inhibit the hydrogen evolution reaction, while also having excellent electrical conductivity and charge and discharge stability. Summary of the Invention

[0006] To solve the above technical problems, the present invention provides a method for preparing a biomass graphitized carbon material. First, ferrocenecarboxylic acid is used as a grafting agent to graft alkali-activated biomass powder to obtain a modified biomass powder uniformly grafted with ferrocenecarboxylic acid. Then, the modified biomass powder, humic acid, organic resin microspheres, and phosphoric acid are used as raw materials to carry out carbonization, graphitization and other reactions under an inert atmosphere to prepare a N, P, and S multi-doped graphitized carbon material. On the one hand, the iron in the grafting agent can increase the degree of graphitization of the carbon material, increase its pore volume, develop its pore structure, reduce the total amount of oxygen-containing functional groups, make the structure more solid, and further improve its conductivity and charge-discharge stability. On the other hand, the N, P, and S doped in the graphitized carbon material help to shift the polarization potential of the hydrogen evolution reaction negatively, thereby inhibiting hydrogen evolution.

[0007] In order to achieve the above objectives, the following technical solutions are adopted:

[0008] A method for preparing a biomass N, P, and S multi-element doped graphitized carbon material comprises the following steps:

[0009] 1) Under ice bath conditions, ferrocenecarboxylic acid, an organic solvent, 4-dimethylaminopyridine (DMAP), and alkali-activated biomass powder were mixed evenly, and dicyclohexylcarbodiimide (DCC) solution was added dropwise. The mixture was stirred and reacted. After the reaction was completed, the mixture was filtered, washed, and dried to obtain the modified biomass powder.

[0010] 2) The modified biomass powder, humic acid, organic resin microspheres and alkaline solution are uniformly mixed, dried for the first time, carbonized, cooled, rinsed, dried for the second time, graphitized, cooled, acid washed, washed with water, and dried for the third time to obtain a biomass graphitized carbon material.

[0011] Furthermore, the preparation method of the alkali-activated biomass powder in step 1) is not particularly limited and can be any commonly used method in the art. Specifically, the method may include: crushing the dry biomass into particles, washing, and drying to obtain biomass powder; adding the biomass powder and alkali solution to a reactor, heating to react; cooling to room temperature after the reaction, filtering, washing, and drying to obtain alkali-activated biomass powder.

[0012] Furthermore, the biomass is selected from one or a combination of two or more of rice husks, coconut shells, wood chips, bamboo, rice straw, corn cobs, walnut shells, bagasse, and pistachio shells; the average particle size of the particles is 1-3 mm, the washing is washing with water 1-3 times, and the drying is vacuum drying at 80-100° C. to constant weight.

[0013] Furthermore, the concentration of the alkali solution is 0.5-0.8 mol / L, and the alkali solution is selected from one or a combination of sodium hydroxide solution and potassium hydroxide solution. The mass-to-volume ratio of the biomass powder to the alkali solution is 1 g: (15-20) mL. The temperature is raised to 180-200°C, the reaction time is 1-3 hours, the washing is performed with water until neutral, and the drying is performed at 100-120°C under vacuum to constant weight. The purpose of the alkali activation step is to increase the reactivity of the hydroxyl groups on the biomass powder.

[0014] Step 1) The organic solvent is selected from one or a combination of two or more of dichloromethane, benzene, and toluene. The amount of ferrocenecarboxylic acid is 5-8wt% of the alkali-activated biomass powder, the alkali-activated biomass powder is 5-10wt% of the organic solvent, the molar ratio of ferrocenecarboxylic acid, DMAP, and DCC is 4-5:4-5:4-5, the concentration of the DCC solution is 0.4-0.6 mol / L, and the solvent of the DCC solution is the same as the above-mentioned organic solvent. The dropwise addition time is 0.5-1.5h, the reaction temperature is 20-30°C, and the reaction time is 12-24h. The washing is performed by alternating washing with saturated sodium bicarbonate solution and water 1-3 times, and the drying is performed at 60-90°C to constant weight. Step 1) Alkali-activated biomass powder is grafted with ferrocenecarboxylic acid as a grafting agent in the presence of DCC as a dehydrating agent and DMAP as a catalyst to obtain a modified biomass powder uniformly grafted with ferrocenecarboxylic acid. Iron acts as a catalyst and can increase the degree of graphitization of the carbon material, thereby increasing its pore volume, developing its pore structure, reducing the total amount of oxygen-containing functional groups, making the structure more solid, and further improving its conductivity and charge-discharge stability.

[0015] In step 2), the organic resin microspheres are selected from one or a combination of polystyrene microspheres and polytetrafluoroethylene microspheres, and have an average particle size of 100-500 μm. Both the modified biomass powder and the organic resin microspheres undergo volume shrinkage during carbonization, but at different rates, forming pores. The alkali solution has a concentration of 40-50 wt%, and is selected from one or a combination of sodium hydroxide and potassium hydroxide.

[0016] In step 2), the mass ratio of the modified biomass powder, humic acid, organic resin microspheres, and alkaline solution is 80-90:10-15:30-35:150-180. Humic acid is a macromolecular organic substance widely found in nature and widely used in agriculture, forestry, animal husbandry, petroleum, chemical industry, building materials, medicine, health care, environmental protection, and other fields. Humic acid is a type of organic substance formed and accumulated from the decomposition and transformation of animal and plant remains, primarily plant remains, through a series of geochemical processes. Humic acid is composed of carbon, hydrogen, oxygen, nitrogen, sulfur, and a small amount of phosphorus. Humic acid is mixed with modified biomass powder and subjected to carbonization and graphitization reactions to produce N-, P-, and S-doped graphitized carbon materials. This helps to shift the polarization potential of the hydrogen evolution reaction negatively, thereby inhibiting hydrogen evolution. The inventors found that humic acid and modified biomass powder have a synergistic effect in inhibiting hydrogen evolution. The ratio of the two should not be too high or too low. Too high or too low is not conducive to inhibiting hydrogen evolution. It is speculated that the graphitization caused by the grafting agent and the above-mentioned heteroatoms will change the surface chemical properties of the carbon material. Too high or too low a ratio is conducive to H evolution. + adsorption and reaction.

[0017] In step 2), the first drying step is performed at 150-180°C to constant weight. The carbonization step is performed at 450-600°C for 2-3 hours. The cooling step is performed naturally to room temperature. The rinsing step is performed with water to recover the alkali solution. The second drying step is performed at 120-150°C to constant weight. The graphitization step is performed under an inert gas atmosphere at a temperature of 1750-1900°C for 4-8 hours. The acid wash step is performed by rinsing the graphitized product 1-5 times with 0.1-0.5 mol / L dilute hydrochloric acid, and the water wash step is performed by rinsing the acid-washed product 1-5 times. The third drying step is performed at 95-105°C to constant weight. The acid wash step removes iron to prevent its adverse effects on the final carbon material and also produces a more porous structure.

[0018] The present invention also provides a biomass N, P, S multi-doped graphitized carbon material prepared by the above method. Preferably, the biomass N, P, S multi-doped graphitized carbon material has a graphitization degree of I D / I G Between 0.50-0.61.

[0019] The present invention also provides a negative electrode lead paste for a lead-carbon battery, using the biomass N, P, S multi-element doped graphitized carbon material as a negative electrode lead paste additive.

[0020] Compared with the prior art, the present invention has the following beneficial effects:

[0021] The invention firstly uses ferrocenecarboxylic acid as a grafting agent to graft alkali-activated biomass powder to obtain modified biomass powder uniformly grafted with ferrocenecarboxylic acid, then uses the modified biomass powder, humic acid, organic resin microspheres and phosphoric acid as raw materials, and performs carbonization, graphitization and other reactions under an inert atmosphere to prepare N, P and S doped graphitized carbon material. On the one hand, the iron in the grafting agent can improve the graphitization degree of the carbon material, increase the pore volume, develop the pore structure, reduce the total amount of oxygen-containing functional groups, make the structure more solid, and further improve the conductivity and charge-discharge stability. On the other hand, the N, P and S doped in the graphitized carbon material help to shift the polarization potential of the hydrogen evolution reaction negatively, thereby inhibiting hydrogen evolution.

[0022] The inventors found that humic acid and modified biomass powder have a synergistic effect in inhibiting hydrogen evolution. It is speculated that the graphitization caused by the grafting agent and the doped heteroatoms will change the surface chemical properties of the carbon material. By adjusting the ratio of the two, the H evolution can be inhibited. + adsorption and reaction. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 This is an electron microscope photo of the biomass graphitized carbon material prepared in Example 1;

[0024] Figure 2 This is a graph showing the specific surface area test data of the biomass graphitized carbon material prepared in Example 1;

[0025] Figure 3 This is the pore size distribution diagram of the specific surface area test of the biomass graphitized carbon material prepared in Example 1. DETAILED DESCRIPTION

[0026] The present invention will be further described below in conjunction with specific embodiment, but is not limited to the content on the specification sheets. Unless otherwise specified, "parts" described in the embodiments of the present invention are all parts by weight. All reagents used are commercially available reagents in this area.

[0027] Polystyrene microspheres with an average particle size of 200 μm were purchased from Shanghai Yiyuan Biotechnology Co., Ltd.

[0028] Example 1

[0029] 1) 200 g of dried coconut shell was crushed into particles with an average particle size of 2.5 mm, washed twice with water, and dried at 90°C to constant weight to obtain 200 g of biomass powder. 200 g of biomass powder and 4 L of 0.5 mol / L sodium hydroxide solution were added to a reactor, heated to 200°C, and reacted for 2 h. After the reaction, the mixture was cooled to room temperature, filtered, washed with water until the pH was neutral, and dried at 90°C to constant weight to obtain alkali-activated biomass powder;

[0030] 2) Under ice bath conditions, 0.04 mol of ferrocenecarboxylic acid, 1150 g of dichloromethane, 0.04 mol of 4-dimethylaminopyridine (DMAP), and 115 g of alkali-activated biomass powder were mixed evenly, and 0.1 L of a 0.5 mol / L dicyclohexylcarbodiimide (DCC) solution (solvent: dichloromethane) was added dropwise. The mixture was stirred at 25°C for 15 h. After the reaction, the mixture was filtered, washed three times with saturated sodium bicarbonate solution and water, and dried at 90°C to constant weight to obtain the modified biomass powder.

[0031] 3) 90 g of modified biomass powder, 10 g of humic acid, 35 g of polystyrene microspheres, and 180 g of 50 wt% sodium hydroxide solution were mixed evenly, dried at 150 ° C for the first time for 18 h to constant weight, carbonized at 600 ° C for 2 h, cooled naturally to room temperature, rinsed with water to remove the alkali solution, dried at 150 ° C for the second time to constant weight, graphitized at 1800 ° C under argon atmosphere for 6 h, cooled naturally to room temperature, and the graphitized product was rinsed 3 times with 0.3 mol / L dilute hydrochloric acid, and then rinsed 3 times with water, and dried at 150 ° C for the third time to constant weight to obtain biomass graphitized carbon material.

[0032] Example 2

[0033] The rest is the same as Example 1, except that in step 2), the amount of alkali-activated biomass powder used is 184 g, and the amount of dichloromethane used is 1840 g.

[0034] Example 3

[0035] The rest is the same as Example 1, except that the amount of modified biomass powder used in step 3) is 80 g.

[0036] Example 4

[0037] The rest is the same as Example 1, except that the amount of modified biomass powder used in step 3) is 70 g.

[0038] Example 5

[0039] The rest is the same as Example 1, except that the amount of modified biomass powder used in step 3) is 100 g.

[0040] Example 6

[0041] The rest is the same as Example 1, except that: 3) 80 g of modified biomass powder, 15 g of humic acid, 30 g of polystyrene microspheres, and 150 g of 50 wt% sodium hydroxide solution were mixed evenly, dried at 150 ° C for a first time for 18 h to constant weight, carbonized at 600 ° C for 2 h, naturally cooled to room temperature, rinsed with water to remove the alkali solution, dried at 150 ° C for a second time to constant weight, graphitized at 1800 ° C under an argon atmosphere for 6 h, and naturally cooled to room temperature. After the graphitized product was rinsed 3 times with 0.3 mol / L dilute hydrochloric acid, then rinsed 3 times with water, and dried at 150 ° C for a third time to constant weight to obtain a biomass graphitized carbon material.

[0042] Comparative Example 1

[0043] The rest is the same as Example 1, except that humic acid is not added in step 3).

[0044] Comparative Example 2

[0045] 1) 200 g of dried coconut shell was crushed into particles with an average particle size of 2.5 mm, washed twice with water, and dried at 90°C to constant weight to obtain 200 g of biomass powder. 200 g of biomass powder and 4 L of 0.5 mol / L sodium hydroxide solution were added to a reactor, heated to 200°C, and reacted for 2 h. After the reaction, the mixture was cooled to room temperature, filtered, washed with water until the pH was neutral, and dried at 90°C to constant weight to obtain alkali-activated biomass powder;

[0046] 2) 90 g of alkali-activated biomass powder, 10 g of humic acid, 35 g of polystyrene microspheres, and 180 g of 50 wt% sodium hydroxide solution were mixed evenly, dried at 150 ° C for the first time for 18 h to constant weight, carbonized at 600 ° C for 2 h, cooled naturally to room temperature, rinsed with water to remove the alkali solution, dried at 150 ° C for the second time to constant weight, graphitized at 1800 ° C under argon atmosphere for 6 h, cooled naturally to room temperature, and the graphitized product was rinsed 3 times with 0.3 mol / L dilute hydrochloric acid, then rinsed 3 times with water, and dried at 150 ° C for the third time to constant weight to obtain biomass graphitized carbon material.

[0047] Comparative Example 3

[0048] The rest is the same as Example 1, except that ferrocenecarboxylic acid is added in the form of a blend:

[0049] 1) 200 g of dried coconut shell was crushed into particles with an average particle size of 2.5 mm, washed twice with water, and dried at 90°C to constant weight to obtain 200 g of biomass powder. 200 g of biomass powder and 4 L of 0.5 mol / L sodium hydroxide solution were added to a reactor, heated to 200°C, and reacted for 2 h. After the reaction, the mixture was cooled to room temperature, filtered, washed with water until the pH was neutral, and dried at 90°C to constant weight to obtain alkali-activated biomass powder;

[0050] 2) 90 g of alkali-activated biomass powder, 7.2 g of ferrocenecarboxylic acid, 10 g of humic acid, 35 g of polystyrene microspheres, and 180 g of 50 wt% sodium hydroxide solution were mixed evenly, dried at 150 ° C for the first time for 18 h to constant weight, carbonized at 600 ° C for 2 h, cooled naturally to room temperature, rinsed with water to remove the alkali solution, dried at 150 ° C for the second time to constant weight, graphitized at 1800 ° C under argon atmosphere for 6 h, cooled naturally to room temperature, and the graphitized product was rinsed 3 times with 0.3 mol / L dilute hydrochloric acid, then rinsed 3 times with water, and dried at 150 ° C for the third time to constant weight to obtain biomass graphitized carbon material.

[0051] Application Example 1

[0052] A. Preparation of electrode: Grind the biomass graphitized carbon material of Example 1: PVDF: acetylene black in a mass ratio of 8:1:1 in a mortar and pestle evenly, then add appropriate amounts of N-methylpyrrolidone and ethanol to prepare a slurry, and then evenly coat it on a 10 mm × 20 mm titanium foil, and vacuum dry it for 24 hours to obtain the electrode.

[0053] B Assemble lead-carbon battery:

[0054] (1) Paste: 50 g of lead powder, 10 g of lead oxide, 0.7 g of the biomass graphitized carbon material prepared in Example 1, 0.8 g of barium sulfate, 0.2 g of acetylene black, 0.8 g of sodium lignosulfonate, 0.8 g of barium stearate, and 0.9 mL of water were mixed and stirred for 10 min to obtain a lead paste.

[0055] (2) Apply lead paste evenly to the positive and negative grids (the lead-calcium alloy negative grid was purchased from Baoding Meilun Nonferrous Metals Co., Ltd., and the lead dioxide positive grid was purchased from Baoji Changli Special Metals Co., Ltd. The size of the positive and negative grids was 70mm×50mm×2mm.), and dry in an oven at 65℃ for 8h, and then at 75℃ for 6h to obtain the positive and negative plates of the lead-carbon battery. Add 150mL of a 1.035g / cm 3 The positive and negative plates were inserted into the beaker on both sides of the beaker, separated by an industrial battery AGM, to simulate a lead-carbon battery. The battery was then connected to the LAND5.8 battery testing system for formation, obtaining qualified positive and negative plates. The formation conditions were as follows: first, let it rest for 2 hours, then charge at a constant current rate of 0.05C for 1 hour, then charge at a constant current rate of 0.1C for 20 hours; after standing for 2 hours, discharge at a constant current rate of 0.1C for 1 hour, then charge at a constant current rate of 0.1C for 10 hours, charge at a constant current rate of 0.2C for 12 hours, and finally charge at a constant current rate of 0.1C for 4 hours.

[0056] (3) Lead-carbon batteries are assembled in the form of 1 positive and 2 negative plates: welding of positive and negative plates, filling of batteries with acid (density of sulfuric acid is 1.27 g / cm 3), battery sealing, battery detection machine activation.

[0057] Application Example 2-6, Comparative Application Example 1-2

[0058] The rest is the same as Application Example 1, except that the biomass graphitized carbon material is prepared according to Example 2-6.

[0059] The biomass graphitized carbon materials prepared in the above examples and comparative examples were tested for specific surface area and resistivity. The electrodes and lead-carbon batteries prepared in the application examples and comparative application examples were subjected to the following other performance tests: For simplicity, the examples and application examples are tested using the same application example number. The results are shown in Table 1.

[0060] 1. Specific surface area and pore size: measured by NOVA 1000e pore structure specific surface area tester. The sample was degassed at 350℃ for 2h and adsorbed with liquid nitrogen at 77K and relative pressure (P / P0) 10 -6 N2 adsorption was carried out in the range of -1, and the specific surface area was calculated by the BET equation.

[0061] 2. Hydrogen evolution performance: The electrode prepared as above was used as the working electrode, a saturated calomel electrode was used as the reference electrode, and a Pt sheet was used as the counter electrode. In a 1 mol / L sulfuric acid solution, a classic three-electrode system was used to perform a linear scan test on the working electrode using a CHI660A electrochemical workstation produced by Shanghai Chenhua Instrument Co., Ltd. The scan range was 0 to -2 V, and the scan rate was 1 mV / s. The hydrogen evolution performance of the material can be determined based on the linear scan voltammetry curve.

[0062] 3. Cycling Performance: To investigate the charge-discharge voltage and cycling characteristics of the battery under the HRPSoC state, cycling tests were conducted. The battery tester used in the experiment was a BTS-5 V / 6 A battery tester manufactured by Shenzhen Xinweier Electronics Co., Ltd. The following charging and discharging schedule was employed: the battery was first placed in a 30-minute standstill and then discharged at 2 A for 84 minutes to reach 50% of its theoretical capacity, or 50% SoC. After a 5-minute standstill, the battery was cycled through the following steps: charge at 4 A for 1 minute, place for 1 minute, discharge at 4 A for 1 minute, and place for 1 minute. The upper and lower charge and discharge voltage limits were set at 2.9 V and 1.7 V, respectively. Cycling terminated when any of the battery's aforementioned cutoff voltages was reached, and the number of cycles at termination was recorded.

[0063] 4. Raman spectroscopy analysis: The degree of graphitization of biomass graphitized carbon materials is analyzed by testing the Raman spectrum of the materials in the range of 500-3000 cm -1 The main characteristic band of Raman spectrum of carbon-based materials is located at 1340cm -1 The D peak at around 1570 cm -1The G peaks on the left and right are caused by disordered carbon atoms and sp 2 The symmetrical stretching vibration of the hybrid carbon atoms is generated, and the intensity ratio of these two characteristic peaks is I D / I G The value can be used to evaluate the degree of graphitization. The smaller the value, the higher the degree of graphitization.

[0064] Table 1 Performance test

[0065] .

[0066] From the graphitization degree test results in Table 1, it can be seen that the grafted ferrocenecarboxylic acid is beneficial to improving the graphitization degree of the carbon material, reducing the resistivity and improving the conductivity. From the hydrogen evolution performance test results, it can be seen that humic acid and modified biomass powder have a significant synergistic effect in inhibiting hydrogen evolution. It is speculated that the graphitization caused by the grafting agent and the doped heteroatoms will change the surface chemical properties of the carbon material. By adjusting the ratio of the two, the H evolution is inhibited. + The adsorption and reaction of the battery are inhibited, the hydrogen evolution reaction is inhibited, the charge and discharge stability is improved, and the corresponding cycle life is increased.

[0067] The present invention adopts biomass as the carbon source for preparing carbon materials, which not only saves costs but also helps improve the performance of lead-carbon batteries.

Claims

1. A method for preparing biomass N, P, S multi-element doped graphitized carbon material, characterized in that: The steps include: 1) Under ice bath conditions, ferrocenecarboxylic acid, an organic solvent, 4-dimethylaminopyridine (DMAP), and alkali-activated biomass powder were mixed evenly, and dicyclohexylcarbodiimide (DCC) solution was added dropwise. The mixture was stirred and reacted. After the reaction was completed, the modified biomass powder was filtered, washed, and dried. 2) uniformly mixing the modified biomass powder, humic acid, organic resin microspheres, and alkali solution, drying for the first time, carbonizing, cooling, rinsing, drying for the second time, graphitizing, cooling, acid washing, washing with water, and drying for the third time to obtain a biomass graphitized carbon material; The mass ratio of the modified biomass powder, humic acid, organic resin microspheres and alkali solution is 80-90:10-15:30-35:150-180.

2. The preparation method according to claim 1, characterized in that Step 1) The amount of ferrocenecarboxylic acid is 5-8wt% of the alkali-activated biomass powder, the alkali-activated biomass powder is 5-10wt% of the organic solvent, and the molar ratio of ferrocenecarboxylic acid, DMAP, and DCC is 4-5:4-5:4-5.

3. The preparation method according to claim 1, characterized in that Step 1) The organic solvent is selected from one or a combination of two or more of dichloromethane, benzene, and toluene; the concentration of the DCC solution is 0.4-0.6 mol / L, and the solvent of the DCC solution is the same as the above organic solvent.

4. The preparation method according to claim 1, characterized in that In step 1), the dropwise addition time is 0.5-1.5 h, the reaction temperature is 20-30° C., and the reaction time is 12-24 h.

5. The preparation method according to claim 1, characterized in that Step 2) The organic resin microspheres are selected from polystyrene microspheres, polytetrafluoroethylene microspheres, or a combination thereof, and the average particle size of the organic resin microspheres is 100-500 μm.

6. The preparation method according to claim 1, characterized in that Step 2) The concentration of the alkali solution is 40-50 wt %, and the alkali solution is selected from sodium hydroxide, potassium hydroxide, or a combination of the two.

7. The preparation method according to claim 1, characterized in that Step 2) The first drying is performed at 150-180°C to constant weight; the carbonization is performed at 450-600°C for 2-3 hours; the second drying is performed at 120-150°C to constant weight; the graphitization is performed in an inert gas atmosphere at a temperature of 1750-1900°C for 4-8 hours; and the third drying is performed at 95-105°C to constant weight.

8. The biomass N, P, S multi-component doped graphitized carbon material prepared by the preparation method according to any one of claims 1 to 7.

9. The biomass N, P, S multi-element doped graphitized carbon material according to claim 8, characterized in that: The graphitization degree of the biomass N, P, S multi-doped graphitized carbon material is I D / I G Between 0.50-0.

61.

10. A negative electrode lead paste for a lead-carbon battery, comprising the biomass N, P, and S multi-component doped graphitized carbon material according to claim 8 or 9 as a negative electrode lead paste additive.

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