Lead-carbon battery negative electrode material based on graded porous carbon and preparation method of lead-carbon battery negative electrode material

Abstract

The invention relates to the technical field of batteries, and discloses a lead-carbon battery negative electrode material based on graded porous carbon and a preparation method thereof.The lead-carbon battery negative electrode material comprises, by weight, 100 parts of lead powder, 0.8-1.5 parts of nitrogen-phosphorus graded porous carbon, 0.5-0.7 part of barium sulfate, 0.1-0.18 part of sodium lignin sulfonate and the like; the preparation method comprises the following steps: reacting novolac epoxy resin with amino-terminated polytriazine phosphamide, and calcining at high temperature to obtain the nitrogen-phosphorus graded porous carbon. After the graded porous carbon is doped with phosphorus, the graphitization degree of the carbon material can be improved, and the electrochemical performance such as the conductivity, the specific capacity and the cycling stability of the negative electrode can be improved. After the graded porous carbon is doped with nitrogen, the hydrogen evolution reaction is inhibited, the hydrogen evolution current is lower, and the defects that the interior of the battery is dry, the internal resistance is increased and the like due to continuous loss of water in electrolyte caused by the hydrogen evolution reaction are overcome.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of batteries, in particular to a lead-carbon battery negative electrode material based on hierarchical porous carbon and a preparation method thereof. BACKGROUND

[0002] Lead-acid batteries have occupied a pivotal position in the energy storage field for more than a hundred years due to their advantages of easy availability of raw materials, low price, good safety performance, and high recovery rate. However, with the development of the times and the progress of science and technology, the shortcomings of traditional lead-acid batteries have gradually become prominent. In high-rate partial state of charge (HRPSoC) conditions, the negative electrode is prone to irreversible sulfation, which causes rapid capacity decay and significant shortening of service life. In addition, the low utilization rate of negative active material, small specific surface area, poor rapid charge-discharge capability, and low energy density seriously limit its application range. In the face of competition from emerging high-performance energy storage devices such as lithium-ion batteries, lead-acid batteries are gradually at a disadvantage.

[0003] Under this background, lead-carbon batteries emerged as the times require. Lead-carbon batteries ingeniously combine the high energy density characteristics of traditional lead-acid batteries with the high-rate performance of supercapacitors. They not only have excellent charge-discharge performance but also effectively suppress negative electrode sulfation by introducing carbon materials, greatly extending the service life of the battery. The market demand for lead-carbon batteries is also showing a rapid growth trend, and they are widely used in new energy storage, electric vehicle auxiliary power, communication base station backup power, and other fields.

[0004] Although lead-carbon batteries exhibit superior performance to traditional lead-acid batteries in many aspects, they still face a series of severe technical challenges in practical applications. Among them, the performance of the negative electrode material is one of the key factors that restrict the overall performance improvement of the battery. In high-rate partial state of charge (HRPSoC) conditions, the irreversible sulfation of the negative electrode is still a difficult problem to be solved. The newly generated fine lead sulfate particles are prone to agglomerate and grow into super-large particles that cannot be converted back to active sponge lead during the Ostwald ripening process, which seriously hinders the normal charge-discharge cycle of the battery and reduces the charge-discharge efficiency and service life of the battery.

[0005] In addition, existing carbon materials also have many problems when used as negative electrode additives in lead-carbon batteries. On the one hand, most carbon materials have a low hydrogen evolution potential, which makes the negative electrode prone to hydrogen evolution during charging, causing continuous loss of water in the electrolyte and eventually leading to battery failure due to thermal runaway. On the other hand, conventional carbon materials have insufficient specific surface area, an imbalanced ratio of micropores and mesopores, and low nitrogen doping efficiency, which results in poor electrolyte wettability, low ion transport efficiency, and high internal resistance, making it difficult to meet the requirements of high-power discharge and rapid charging of lead-carbon batteries. SUMMARY

[0006] In view of the deficiencies of the prior art, the application provides a lead-carbon battery negative electrode material based on hierarchical porous carbon and a preparation method thereof, and problems such as poor capacity and cycle stability of the lead-carbon battery negative electrode material are solved.

[0007] The technical scheme of the application is as follows: a lead-carbon battery negative electrode material based on hierarchical porous carbon and a preparation method thereof; the lead-carbon battery negative electrode material comprises the following components: 100 parts by weight of lead powder, 0.8-1.5 parts by weight of nitrogen-phosphorus hierarchical porous carbon, 0.5-0.7 parts by weight of barium sulfate, 0.1-0.18 parts by weight of sodium lignosulfonate, 0.02-0.04 parts by weight of humic acid, and 0.05-0.06 parts by weight of short carbon fibers.

[0008] The preparation method of the lead-carbon battery negative electrode material is as follows:

[0009] (1) phenolic epoxy resin and amino-terminated polytriazine phosphoramide are added to N,N-dimethylformamide, and after stirring and reaction, the solution is poured into ethanol to precipitate a precipitate, the precipitate is dried after filtration, and a cross-linked porous phenolic resin is obtained.

[0010] (2) the cross-linked porous phenolic resin is added to a tube furnace and calcined in a nitrogen atmosphere, and after cooling, nitrogen-phosphorus hierarchical porous carbon is obtained.

[0011] (3) the nitrogen-phosphorus hierarchical porous carbon, barium sulfate, sodium lignosulfonate, humic acid, short carbon fibers and ethanol are mixed and ball-milled and dispersed in a ball mill jar, and then mixed with the lead powder, stirred and dried to remove the ethanol, and then deionized water is added, stirred, and diluted sulfuric acid is added dropwise, stirred and mixed uniformly, coated on a negative electrode grid plate, roll-pressed and compacted, placed in a constant-temperature and constant-humidity box for curing, and a lead-carbon battery negative electrode material based on hierarchical porous carbon is obtained.

[0012] Preferably, the ratio of the phenolic epoxy resin to the amino-terminated polytriazine phosphoramide in (1) is (65-90):(10-35).

[0013] Preferably, the reaction in (1) is carried out at 90-120℃ for 12-24h.

[0014] Preferably, the calcination process in (2) is to heat at a heating rate of 5-10℃ / min to 700-850℃, and then keep the temperature for 2-3h.

[0015] Preferably, the rotation speed for ball-milling and dispersing in (3) is 200-400r / min, and the time is 10-20min.

[0016] Preferably, the mass fraction of the diluted sulfuric acid in (3) is 1.2-1.4g / mL.

[0017] Preferably, the process of curing in (3) is first curing at 40-50 DEG C for 36-48h; then curing at 70-80 DEG C for 12-18h.

[0018] Preferably, the preparation method of the terminal amino polytriazine phosphoramide is: adding phenyl dichlorophosphate, triethylamine and 2, 4, 6-tris (4-aminophenyl) -1, 3, 5-triazine in a proportion of (1.25-1.4) mol: (3-3.3) mol: 1 mol to acetonitrile at 0-5 DEG C, stirring and reacting at 20-25 DEG C for 18-24h, washing with water and ethanol after filtration, and drying to obtain the terminal amino polytriazine phosphoramide.

[0019] The application has the beneficial technical effects that: phenyl dichlorophosphate and 2, 4, 6-tris (4-aminophenyl) -1, 3, 5-triazine are used for polymerization to obtain the terminal amino polytriazine phosphoramide with a branched molecular chain structure of dendritic, and the terminal contains a large number of active amino groups, which react with the epoxy groups of the phenolic epoxy resin, realizes the chemical crosslinking of the phenolic resin, makes the phenolic resin form a three-dimensional network structure, is beneficial to improve the porosity of the carbon material after calcination, thereby improving the specific surface area of the carbon material, and after high-temperature calcination, the traditional pore-forming agent such as potassium hydroxide does not need to be added, and the hierarchical porous carbon with high specific surface area can be obtained, meanwhile, the polytriazine phosphoramide contains a large number of benzene ring structures, and the phenolic resin can be used as a carbon source to obtain the carbon material with high carbon content and high graphitization.

[0020] The application uses lead powder, nitrogen-phosphorus hierarchical porous carbon, barium sulfate, sodium lignosulfonate and the like as raw materials to form a lead-carbon negative electrode material, the nitrogen-phosphorus hierarchical porous carbon can improve the graphitization degree of the carbon material after being doped with phosphorus, improve the electrochemical performance such as conductivity and specific capacity of the negative electrode, and the high specific surface area can enhance the electrochemical reaction active sites, inhibit the growth of lead sulfate in the electrochemical cycle process of the negative electrode, so that the negative electrode material has higher specific capacity and capacity retention rate and excellent cycle stability.

[0021] After the hierarchical porous carbon is doped with nitrogen, the electronegativity of nitrogen reduces the current density of surrounding carbon atoms, weakens the combination ability of carbon and hydrogen, thereby inhibiting the hydrogen evolution reaction, and the hierarchical porous carbon shows lower hydrogen evolution current, overcomes the problem that the water in the electrolyte is continuously consumed due to the hydrogen evolution reaction, and further causes the problems such as internal dryness and internal resistance increase of the battery. DETAILED DESCRIPTION

[0022] The technical solutions in the embodiments of the application will be clearly and completely described below with reference to the embodiments of the application. Obviously, the described embodiments are only part of the embodiments of the application, rather than all the embodiments of the application. Based on the embodiments in the application, all other embodiments obtained by those skilled in the art without creative labor fall within the protection scope of the application.

[0023] The phenolic epoxy resin model is F51, which is purchased from Wuhan Smc Biological Technology Co., Ltd.

[0024] Example 1:

[0025] (1) At 0°C, 14 mmol of phenyl dichlorophosphate, 30 mmol of triethylamine, and 10 mmol of 2,4,6-tris(4-aminophenyl)-1,3,5-triazine were added to 50 mL of acetonitrile, and after stirring, the reaction was stirred at 25°C for 24 h. After filtration, the product was washed with water and ethanol and dried to obtain an amino-terminated polytriazine phosphoramide. The preparation reaction formula is as follows:

[0026] .

[0027] (2) 18 g of phenolic epoxy resin and 2 g of amino-terminated polytriazine phosphoramide were added to 150 mL of N,N-dimethylformamide, and the temperature was raised to 110°C. The reaction was stirred for 12 h, and the solution was poured into ethanol to precipitate the product. After filtration and drying, a cross-linked porous phenolic resin was obtained.

[0028] (3) The cross-linked porous phenolic resin was placed in a tube furnace and heated to 700°C at a rate of 5°C / min under a nitrogen atmosphere, and calcined for 3 h. After cooling, nitrogen-phosphorus hierarchical porous carbon was obtained.

[0029] (4) 8 g of nitrogen-phosphorus hierarchical porous carbon, 6.3 g of barium sulfate, 1.5 g of sodium lignosulfonate, 0.2 g of humic acid, 0.6 g of short carbon fibers (length of 3 mm), and 100 mL of ethanol were mixed and ball-milled in a ball mill tank for 15 min at a speed of 200 r / min. Then, 1 kg of lead powder (containing about 72% of lead oxide) was added and stirred to remove ethanol. Then, 120 mL of deionized water was added, and after stirring, 70 mL of dilute sulfuric acid with a mass fraction of 1.4 g / mL was added and stirred to mix. The mixture was coated on a negative grid plate and rolled to compact it. The compacted material was placed in a constant temperature and humidity box, and first cured at 40°C for 48 h at a relative humidity of 90%. Then, it was cured at 80°C for 12 h at a relative humidity of 0%, to obtain a lead-carbon battery negative electrode material based on hierarchical porous carbon.

[0030] Example 2:

[0031] (1) At 0°C, 14 mmol of phenyl dichlorophosphate, 30 mmol of triethylamine, and 10 mmol of 2,4,6-tris(4-aminophenyl)-1,3,5-triazine were added to 50 mL of acetonitrile, and after stirring, the reaction was stirred at 20°C for 24 h. After filtration, the product was washed with water and ethanol and dried to obtain an amino-terminated polytriazine phosphoramide.

[0032] (2) 15 g of phenolic epoxy resin and 5 g of amino-terminated polytriazine phosphoramide were added into 150 mL of N,N-dimethylformamide, and the temperature was raised to 90°C. The mixture was stirred for 24 h. The solution was poured into ethanol, and the precipitate was separated and dried to obtain cross-linked porous phenolic resin.

[0033] (3) The cross-linked porous phenolic resin was added into a tube furnace, and the temperature was raised to 850°C at a rate of 10°C / min under a nitrogen atmosphere. The mixture was calcined for 2 h, and then cooled to obtain nitrogen-phosphorus hierarchical porous carbon.

[0034] (4) 11 g of nitrogen-phosphorus hierarchical porous carbon, 7 g of barium sulfate, 1 g of sodium lignosulfonate, 0.3 g of humic acid, 0.5 g of chopped carbon fiber (3 mm in length), and 100 mL of ethanol were mixed and dispersed in a ball mill tank at a speed of 400 r / min for 10 min. Then, 1 kg of lead powder (containing about 72% of lead oxide) was added, and the mixture was stirred and dried to remove ethanol. Then, 130 mL of deionized water was added, and the mixture was stirred and dropped with 80 mL of dilute sulfuric acid with a mass fraction of 1.2 g / mL. The mixture was stirred and coated on a negative grid plate. The mixture was rolled and compacted, and then placed in a constant temperature and humidity box. The mixture was first cured at 50°C for 36 h at a relative humidity of 95%. Then, the mixture was cured at 80°C for 12 h at a relative humidity of 0% to obtain a lead-carbon battery negative electrode material based on hierarchical porous carbon.

[0035] Example 3:

[0036] (1) 12.5 mmol of phenyl phosphorodichloridate, 33 mmol of triethylamine, and 10 mmol of 2,4,6-tris(4-aminophenyl)-1,3,5-triazine were added into 40 mL of acetonitrile at 5°C. The mixture was stirred and reacted at 25°C for 18 h. The mixture was filtered, washed with water and ethanol, and dried to obtain amino-terminated polytriazine phosphoramide.

[0037] (2) 13 g of phenolic epoxy resin and 7 g of amino-terminated polytriazine phosphoramide were added into 150 mL of N,N-dimethylformamide, and the temperature was raised to 120°C. The mixture was stirred for 12 h. The solution was poured into ethanol, and the precipitate was separated and dried to obtain cross-linked porous phenolic resin.

[0038] (3) The cross-linked porous phenolic resin was added into a tube furnace, and the temperature was raised to 750°C at a rate of 5°C / min under a nitrogen atmosphere. The mixture was calcined for 3 h, and then cooled to obtain nitrogen-phosphorus hierarchical porous carbon.

[0039] (4) 15 g of nitrogen-phosphorus hierarchical porous carbon, 5 g of barium sulfate, 1.8 g of sodium lignosulfonate, 0.4 g of humic acid, 0.5 g of short carbon fibers (length of 3 mm), 120 mL of ethanol were mixed and ball-milled in a ball mill tank for 20 min at a rotation speed of 200 r / min; then 1 kg of lead powder (lead oxide content of about 72%) was mixed, stirred, and then dried to remove ethanol, and then 130 mL of deionized water was added, stirred, and 70 mL of dilute sulfuric acid with a mass fraction of 1.4 g / mL was added dropwise, stirred and mixed uniformly, coated on the negative grid plate grid, rolled and compacted, placed in a constant temperature and humidity box, first cured at 50°C for 36 h at a relative humidity of 95%; then cured at 80°C for 12 h at a relative humidity of 0%, to obtain a lead-carbon battery negative electrode material based on hierarchical porous carbon.

[0040] Comparative Example 1, the difference between this comparative example and Example 1 is that nitrogen-phosphorus hierarchical porous carbon is not added.

[0041] (1) 6.3 g of barium sulfate, 1.5 g of sodium lignosulfonate, 0.2 g of humic acid, 0.6 g of short carbon fibers (length of 3 mm), 100 mL of ethanol were mixed and ball-milled in a ball mill tank for 15 min at a rotation speed of 200 r / min; then 1 kg of lead powder (lead oxide content of about 72%) was mixed, stirred, and then dried to remove ethanol, and then 120 mL of deionized water was added, stirred, and 70 mL of dilute sulfuric acid with a mass fraction of 1.4 g / mL was added dropwise, stirred and mixed uniformly, coated on the negative grid plate grid, rolled and compacted, placed in a constant temperature and humidity box, first cured at 40°C for 48 h at a relative humidity of 90%; then cured at 80°C for 12 h at a relative humidity of 0%, to obtain a lead-carbon battery negative electrode material.

[0042] Comparative Example 2, the difference between this comparative example and Example 1 is that melamine is used instead of 2,4,6-tris(4-aminophenyl)-1,3,5-triazine.

[0043] (1) 14 mmol of phenyl phosphorodichloridate, 30 mmol of triethylamine, 10 mmol of melamine were added to 50 mL of acetonitrile at 0°C, stirred and reacted at 25°C for 24 h, filtered and washed with water and ethanol, and dried to obtain polytriazine phosphoramide.

[0044] (2) 18 g of phenolic epoxy resin, 2 g of polytriazine phosphoramide were added to 150 mL of N,N-dimethylformamide, heated to 110°C, and stirred for 12 h, the solution was poured into ethanol, and the precipitate was separated, filtered and dried to obtain polytriazine phosphoramide-phenolic resin.

[0045] (3) The polytriazine phosphoramide-phenolic resin was added to a tube furnace, heated to 700°C at a heating rate of 5°C / min in a nitrogen atmosphere, and heat-treated for 3 h, and then cooled to obtain a nitrogen-phosphorus-carbon material.

[0046] (4) 8 g of nitrogen-phosphorus-carbon material, 6.3 g of barium sulfate, 1.5 g of sodium lignosulfonate, 0.2 g of humic acid, 0.6 g of short carbon fiber (length of 3 mm), 100 mL of ethanol were mixed and ball-milled in a ball mill tank for 15 min at a rotation speed of 200 r / min; then 1 kg of lead powder (content of lead oxide about 72%) was mixed, stirred, and then dried to remove ethanol, then 120 mL of deionized water was added, stirred, and 70 mL of dilute sulfuric acid with a mass fraction of 1.4 g / mL was added dropwise, stirred and mixed uniformly, coated on the negative grid plate grid, rolled and compacted, placed in a constant temperature and humidity box, first cured at 40°C for 48 h, relative humidity 90%; then cured at 80°C for 12 h, relative humidity 0%, to obtain a carbon material-based negative material for lead-carbon batteries.

[0047] Comparative Example 3, the difference between this comparative example and Example 1 is that 1,3,5-tris(4-aminophenyl)benzene (CAS No. 118727-34-7) is used instead of 2,4,6-tris(4-aminophenyl)-1,3,5-triazine.

[0048] (1) 14 mmol of phenyl phosphorodichloridate, 30 mmol of triethylamine, 10 mmol of 1,3,5-tris(4-aminophenyl)benzene were added to 50 mL of acetonitrile at 0°C, stirred and reacted at 25°C for 24 h, filtered, washed with water and ethanol, and dried to obtain an amino-terminated polyphosphoramide.

[0049] (2) 18 g of phenolic epoxy resin, 2 g of amino-terminated polyphosphoramide were added to 150 mL of N,N-dimethylformamide, heated to 110°C, and stirred for 12 h. The solution was poured into ethanol, and the precipitate was separated, filtered, and dried to obtain a cross-linked porous phenolic resin.

[0050] (3) The cross-linked porous phenolic resin was added to a tube furnace, heated to 700°C at a heating rate of 5°C / min in a nitrogen atmosphere, and heat-treated for 3 h, and then cooled to obtain a phosphorus hierarchical porous carbon.

[0051] (4) 8 g of phosphorus hierarchical porous carbon, 6.3 g of barium sulfate, 1.5 g of sodium lignosulfonate, 0.2 g of humic acid, 0.6 g of short carbon fibers (length of 3 mm), 100 mL of ethanol were mixed and dispersed in a ball mill jar for 15 min at a rotation speed of 200 r / min; then mixed with 1 kg of lead powder (about 72% of lead oxide content), after stirring, the ethanol was removed by drying, then 120 mL of deionized water was added, after stirring, 70 mL of dilute sulfuric acid with a mass fraction of 1.4 g / mL was added dropwise, stirred and mixed uniformly, coated on the negative grid plate grid, rolled and compacted, placed in a constant temperature and humidity box, first cured at 40°C for 48 h, relative humidity 90%; then cured at 80°C for 12 h, relative humidity 0%, to obtain a lead-carbon battery negative electrode material based on hierarchical porous carbon.

[0052] Comparative Example 4: 4,4'-diaminotriphenyl (CAS No. 3365-85-3) was used instead of 2,4,6-tris(4-aminophenyl)-1,3,5-triazine.

[0053] (1) 14 mmol of phenyl phosphorodichloridate, 30 mmol of triethylamine, 10 mmol of 4,4'-diaminotriphenyl were added to 50 mL of acetonitrile at 0°C, after stirring, the reaction was carried out at 25°C for 24 h, after filtration, washed with water and ethanol, and dried to obtain an amino-terminated polyphosphonamide.

[0054] (2) 18 g of phenolic epoxy resin, 2 g of amino-terminated polyphosphonamide were added to 150 mL of N,N-dimethylformamide, heated to 110°C, and stirred for 12 h, the solution was poured into ethanol, and the precipitate was separated, filtered and dried to obtain a cross-linked phenolic resin.

[0055] (3) The cross-linked phenolic resin was added to a tube furnace, heated to 700°C at a heating rate of 5°C / min in a nitrogen atmosphere, and calcined for 3 h, and then cooled to obtain a phosphorus-carbon material.

[0056] (4) 8 g of phosphorus-carbon material, 6.3 g of barium sulfate, 1.5 g of sodium lignosulfonate, 0.2 g of humic acid, 0.6 g of short carbon fibers (length of 3 mm), 100 mL of ethanol were mixed and dispersed in a ball mill jar for 15 min at a rotation speed of 200 r / min; then mixed with 1 kg of lead powder (about 72% of lead oxide content), after stirring, the ethanol was removed by drying, then 120 mL of deionized water was added, after stirring, 70 mL of dilute sulfuric acid with a mass fraction of 1.4 g / mL was added dropwise, stirred and mixed uniformly, coated on the negative grid plate grid, rolled and compacted, placed in a constant temperature and humidity box, first cured at 40°C for 48 h, relative humidity 90%; then cured at 80°C for 12 h, relative humidity 0%, to obtain a lead-carbon battery negative electrode material based on carbon material.

[0057] The specific surface area of the nitrogen-phosphorus hierarchical porous carbon material is tested by isothermal nitrogen adsorption-desorption method through a full-automatic specific surface area analyzer.

[0058] The lead-carbon battery negative electrode material is used as a working electrode, a saturated calomel electrode is used as a reference electrode, a platinum electrode is used as a counter electrode, a glass fiber felt type diaphragm is used as a diaphragm, and a mass fraction of 1.28 g / mL sulfuric acid solution is used as an electrolyte to assemble a battery. The electrochemical performance and hydrogen evolution behavior of the battery are tested by cyclic voltammetry through an electrochemical analyzer, the voltage range is-1.5 to 0.8 V, and the scanning rate is 0.05 mV / s. The specific capacitance of the battery is tested by constant current charge-discharge method through a battery charge-discharge test system, and the rate is 0.1 C.

[0059] Table 1 Specific surface area of carbon material

[0060]

[0061] After testing, the specific surface area of the nitrogen-phosphorus hierarchical porous carbon of examples 1-3 reaches 962.8-1637.6 m 2 / g, mainly because the end amino polytriazine phosphoramide presents a branched molecular chain structure, and a large number of active amino groups are contained at the end, which react with the epoxy groups of the phenolic epoxy resin, realizing chemical crosslinking of the phenolic resin, so that the phenolic resin forms a three-dimensional network structure, which is beneficial to improve the porosity of the carbon material after calcination, thereby improving the specific surface area. After high-temperature calcination, without adding traditional potassium hydroxide and other pore-forming agents, a hierarchical porous carbon with high specific surface area can be obtained. At the same time, polytriazine phosphoramide contains a large number of benzene ring structures, and can obtain a carbon material with high carbon content and high graphitization by using phenolic resin as a carbon source.

[0062] In comparative example 2, melamine and dichlorophenyl phosphate are used for polymerization reaction to obtain polytriazine phosphoramide, the end of which is the amino group of melamine, which has low activity and poor reaction with the epoxy groups of the phenolic epoxy resin, so that it is difficult to crosslink with the phenolic epoxy resin to form a three-dimensional network structure, and the specific surface area of the carbon material after calcination is low. In addition, the carbon content of melamine is low, which is not conducive to improving the carbon performance and graphitization degree of the carbon material.

[0063] In comparative example 4, dichlorophenyl phosphate and 1,3,5-tris(4-aminophenyl)benzene are used for polymerization reaction to generate end amino polyphosphoramide, which is a linear molecular chain without forming a branched molecular chain structure. Only the amino groups are contained at both ends, which react with the epoxy groups of the phenolic resin without forming a three-dimensional network structure. After high-temperature calcination, it is not conducive to improving the pore structure of the carbon material, resulting in a low surface area.

[0064] Table 2 Specific capacitance test of battery

[0065]

[0066] Table 3 Hydrogen evolution current test

[0067]

[0068] Compared with Comparative Examples 1 to 4, the discharge specific capacity of the lead-carbon negative electrode of each of the examples is high, and the capacity retention rate after 500 cycles is large, mainly because the nitrogen-phosphorus hierarchical porous carbon is added, the phosphorus-containing groups generate phosphoric acid substances at high temperature, after phosphorus doping, the graphitization degree of the carbon material can be improved, the electrical conductivity, specific capacity and other electrochemical properties of the negative electrode are improved, at the same time, the high specific surface area can enhance the electrochemical reaction active sites, inhibit the growth of lead sulfate in the electrochemical cycle process of the negative electrode, so that the negative electrode material has higher specific capacity and capacity retention rate, and excellent cycle stability. At the same time, after the porous carbon is doped with nitrogen, due to the electronegativity of nitrogen, the current density of the surrounding carbon atoms is reduced, the bonding ability of carbon and hydrogen is weakened, thereby inhibiting the progress of the hydrogen evolution reaction, and showing lower hydrogen evolution current, only -5.7 to -21.8 A / g.

[0069] The foregoing description of specific exemplary embodiments of the application is intended to be illustrative only and is not intended to limit the application to the precise forms described. Many modifications and variations are possible in light of the above teachings without departing from the spirit or essential characteristics of the present application. The exemplary embodiments were chosen and described in order to explain the principles of the application and its practical application and to allow others skilled in the art to understand the application for various exemplary embodiments with various modifications being applicable. The scope of the application is intended to be defined by the claims and their equivalents.

Claims

1. A lead-carbon battery anode material based on hierarchical porous carbon, characterized in that, The lead-carbon battery anode material comprises the following components: 100 parts by weight of lead powder, 0.8-1.5 parts by weight of nitrogen-phosphorus graded porous carbon, 0.5-0.7 parts by weight of barium sulfate, 0.1-0.18 parts by weight of sodium lignosulfonate, 0.02-0.04 parts by weight of humic acid, and 0.05-0.06 parts by weight of short-cut carbon fibers. The method for preparing the nitrogen-phosphorus graded porous carbon is as follows: (1) Add phenolic epoxy resin and amino-terminated polytriazine phosphoramide to N,N-dimethylformamide, stir and react, pour the solution into ethanol, precipitate out, filter and dry the precipitate to obtain cross-linked porous phenolic resin. (2) The cross-linked porous phenolic resin was added to a tube furnace and calcined in a nitrogen atmosphere. After cooling, nitrogen-phosphorus graded porous carbon was obtained.

2. The lead-carbon battery anode material based on hierarchical porous carbon according to claim 1, characterized in that, The ratio of phenolic epoxy resin to amino-terminated polytriazine phosphoramide in (1) is (65-90):(10-35).

3. The lead-carbon battery anode material based on hierarchical porous carbon according to claim 1, characterized in that, The reaction in (1) is carried out at 90-120℃ for 12-24 hours.

4. The lead-carbon battery anode material based on hierarchical porous carbon according to claim 1, characterized in that, The calcination process in (2) involves heating at a rate of 5-10℃ / min to 700-850℃, and then holding the temperature for 2-3 hours.

5. The lead-carbon battery anode material based on hierarchical porous carbon according to claim 1, characterized in that, The preparation method of the terminal amino polytriazine phosphoramide in (2) is as follows: at 0-5℃, add acetonitrile in the ratio of (1.25-1.4) mol: (3-3.3) mol: 1 mol dichlorophosphate, triethylamine, and 2,4,6-tris(4-aminophenyl)-1,3,5-triazine. After stirring, stir and react at 20-25℃ for 18-24 h. After filtration, wash and dry to obtain terminal amino polytriazine phosphoramide.

6. A method for preparing a lead-carbon battery anode material based on hierarchical porous carbon as described in any one of claims 1-5, characterized in that, The preparation method includes: mixing nitrogen-phosphorus graded porous carbon, barium sulfate, sodium lignosulfonate, humic acid, chopped carbon fibers, and ethanol, dispersing them by ball milling in a ball mill jar, then mixing them with lead powder, stirring, drying to remove ethanol, adding deionized water, stirring, adding dilute sulfuric acid dropwise, stirring to mix evenly, coating them on a negative electrode grid plate, rolling and compacting them, and placing them in a constant temperature and humidity chamber for curing to obtain a lead-carbon battery negative electrode material based on graded porous carbon.

7. The method for preparing lead-carbon battery anode material based on hierarchical porous carbon according to claim 6, characterized in that, The ball milling dispersion is performed at a speed of 200-400 r / min for 10-20 min.

8. The method for preparing the lead-carbon battery anode material based on hierarchical porous carbon as described in claim 6, characterized in that, The mass fraction of the dilute sulfuric acid is 1.2-1.4 g / mL.

9. The method for preparing lead-carbon battery anode material based on hierarchical porous carbon according to claim 6, characterized in that, The curing process involves first curing at 40-50℃ for 36-48 hours, and then curing at 70-80℃ for 12-18 hours.

Images