CN110518243B - Application of lignin in preparation of lithium battery graphite negative electrode material - Google Patents
Application of lignin in preparation of lithium battery graphite negative electrode material Download PDFInfo
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- CN110518243B CN110518243B CN201910769546.6A CN201910769546A CN110518243B CN 110518243 B CN110518243 B CN 110518243B CN 201910769546 A CN201910769546 A CN 201910769546A CN 110518243 B CN110518243 B CN 110518243B
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M10/00—Secondary cells; Manufacture thereof
- H01M10/05—Accumulators with non-aqueous electrolyte
- H01M10/052—Li-accumulators
- H01M10/0525—Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M4/00—Electrodes
- H01M4/02—Electrodes composed of, or comprising, active material
- H01M4/36—Selection of substances as active materials, active masses, active liquids
- H01M4/60—Selection of substances as active materials, active masses, active liquids of organic compounds
- H01M4/602—Polymers
- H01M4/606—Polymers containing aromatic main chain polymers
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- H—ELECTRICITY
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- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M4/00—Electrodes
- H01M4/02—Electrodes composed of, or comprising, active material
- H01M2004/026—Electrodes composed of, or comprising, active material characterised by the polarity
- H01M2004/027—Negative electrodes
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- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
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Abstract
The invention discloses an application of lignin in preparation of a lithium battery graphite cathode material, which comprises the following steps: and (2) carrying out hydrolysis reaction on the biomass in an acid solution to obtain a reaction solution, namely a hydrolyzed feed solution, adding 2-10 volume times of water into the hydrolyzed feed solution, stirring, separating out solids, filtering, washing filter residues with clear water, and drying to obtain the lignin. The method can completely liquefy and hydrolyze the biomass, and then extract the lignin generated by liquefying and hydrolyzing the biomass, the lignin has high aromaticity and low sulfur content, and has better performance parameters such as first discharge specific capacity, first coulombic efficiency, powder compaction density, graphitization degree, fixed carbon content and the like when being applied to the preparation of the lithium battery graphite cathode material.
Description
Technical Field
The invention relates to application of lignin in preparation of a lithium battery graphite negative electrode material.
Background
The biomass is mainly stored in the form of agricultural and forestry wastes in a large amount in our lives, the domestic biomass wastes are derived from straws of crops such as soybean, corn and the like, and meanwhile, a furniture factory also generates a large amount of sawdust and wood shavings in the furniture manufacturing process, and the environment pollution can be caused by improper treatment. The theoretical yield of the Chinese straws in 2017 reaches 8.84 hundred million tons, and the amount of the collectable resources reaches 7 hundred million tons, wherein rice straws account for 25 percent, wheat straws account for 18.3 percent, corn straws account for 33 percent, cotton straws account for 3 percent, and rape flowers and peanuts account for 4.4 percent. Mainly distributed in 13 main food production areas such as Liaoning, Jilin, Heilongjiang and the like, and the straw resource amount accounts for more than 70 percent of the total amount.
Generally, the agricultural biomass waste has the following treatment methods: 1) the field is returned to the field by burning on the spot, but serious air pollution is caused, so the country specially produces the 'method for forbidding burning the straws and comprehensively utilizing and managing' to forbid the outdoor burning of the straws. 2) Biomass power generation, and agricultural biomass waste is directly put into a power generation boiler. Although the method solves the pollution problem caused by local incineration, the utilization rate of the biomass is low. 3) Biomass thermal cracking (e.g., chinese patent 201210048116.3, biomass is thermally cracked to produce biomass tar): the biomass is decomposed into biomass charcoal, biomass tar or pyrolysis gas by high-temperature (400-. The main fuel uses are: low calorific value biomass pyrolysis gas and biomass tar. Although the method realizes the conversion of biomass into biofuel, the added value of the biofuel product is low.
However, in the prior art, no literature report on the preparation of a high value-added graphite negative electrode material for a lithium battery by using biomass as a starting material is provided. In the prior art, petroleum coke is generally used as a raw material for preparing artificial graphite, but the petroleum coke has the following defects: 1. high content of heavy metal, 2, high sulfur content. Secondly, natural graphite is also a common material used as a negative electrode material of a lithium battery, but the natural material has more impurities, and the separation and extraction of the impurities needs to use toxic chlorine gas, thereby inevitably increasing the complexity of the process. Moreover, petroleum and natural graphite are non-renewable resources, and the large amount of petroleum coke causes problems of global warming, environmental pollution and the like.
Therefore, the development of a novel method for preparing the graphite cathode material of the lithium battery is of great significance.
Disclosure of Invention
Aiming at the technical problems in the prior art, the invention aims to provide the application of lignin in the preparation of the lithium battery graphite cathode material.
The application of the lignin in preparing the lithium battery graphite cathode material is characterized in that the preparation process of the lignin is as follows: and (2) carrying out hydrolysis reaction on the biomass in an acid solution to obtain a reaction solution, namely a hydrolyzed feed solution, adding 2-10 volume times of water into the hydrolyzed feed solution, stirring, separating out solids, filtering, washing filter residues with clear water, and drying to obtain the lignin.
The application of the lignin in the preparation of the lithium battery graphite cathode material is characterized in that the lignin is used as a raw material, and the preparation of the lithium battery graphite cathode material comprises the following steps:
1) mixing lignin and a stabilizer solution according to a mass ratio of 1: 2-12, standing and stabilizing at 40-70 ℃ for 3-6 hours, filtering, and drying filter residues to obtain stable lignin;
2) placing the stabilized lignin obtained in the step 1) in a rotary kiln, and calcining for 2-4 hours at 1200-1500 ℃ in a nitrogen protective atmosphere to obtain calcined lignin;
3) placing the calcined lignin obtained in the step 2) in a graphitization furnace, calcining for 3-15 hours at 2500-2800 ℃ in an argon protective atmosphere, and naturally cooling to room temperature to obtain the lithium battery graphite cathode material.
The application of the lignin in the preparation of the lithium battery graphite cathode material is characterized in that the stabilizer solution is a diammonium hydrogen phosphate aqueous solution with the mass concentration of 10-20%.
The application of the lignin in preparing the lithium battery graphite cathode material is characterized in that a reaction solution obtained by hydrolysis reaction of biomass in an acid solution is prepared according to the following processes:
s1: adding biomass particles into a reaction kettle, adding a water cosolvent in an anaerobic state, heating to 150-220 ℃ under stirring, adding Lewis acid, and performing hydrolysis reaction for 20-40 minutes to obtain a hydrolyzed biomass mixed solution;
s2: and (4) adding alkali into the biomass mixed liquid obtained in the step (S1) to neutralize and adjust the pH value to 4.5-8, cooling, and filtering to remove precipitates obtained by neutralization and ash in the biomass to obtain the reaction liquid.
The application of the lignin in the preparation of the lithium battery graphite cathode material is characterized in that in the step S1, the water content of biomass particles is less than 8%, the particle size of the particles is less than 25mm, and the biomass is any one or a mixture of several of wood, straws, paper products, pine, grasses, rice husks, bagasse, cotton, jute, flax, bamboo, sisal, abaca, straws and corncobs.
The application of the lignin in the preparation of the lithium battery graphite cathode material is characterized in that in the step S1, the mass ratio of the water cosolvent is 1: 1-1: 5 water and tetrahydrofuran.
The application of the lignin in preparing the lithium battery graphite cathode material is characterized in that in the step S1, the mass ratio of the biomass to the water cosolvent is 1: 2-7; the Lewis acid is at least one of sulfuric acid, hydrochloric acid and nitric acid, and the mass of the Lewis acid is 0.3-3% of that of the water cosolvent.
Compared with the prior art, the invention has the following beneficial effects:
1) the reaction liquid after the biomass is subjected to hydrolysis reaction in the acid solution is marked as hydrolyzed feed liquid, and the hydrolyzed feed liquid contains biomass hydrolysis products such as: sugar of C5-C6, furfural, levulinic acid, hydrolyzed lignin and the like, wherein the hydrolyzed lignin is the aromatic hydrocarbon organic matter. And adding a certain amount of water into the hydrolyzed feed liquid for mixing, so that the solubility of lignin in the hydrolyzed feed liquid can be reduced, and then the lignin is separated out (biomass hydrolysis products such as sugar, furfural and levulinic acid of C5-C6 are basically dissolved in the hydrolyzed feed liquid, and can be used as liquid fuel, plant nutrient solution and the like. After the separated lignin is cleaned and dried by clear water, the obtained lignin product has high aromaticity, and the obtained lignin has low sulfur content and ash content, and is particularly suitable for preparing downstream graphite materials with high added value.
2) When the lignin extracted by the invention is used for preparing the lithium battery graphite cathode material, the lignin has better performance parameters of specific discharge capacity for the first time, coulombic efficiency for the first time, powder compaction density, graphitization degree and fixed carbon content, and meets the use standard of the lithium battery cathode material. Secondly, the method can efficiently utilize renewable resources such as biomass straws and the like, reduces the consumption rate of the lithium battery cathode material to natural resources, reduces environmental pollution and improves economic benefits.
Detailed Description
The present invention is further illustrated by the following examples, which should not be construed as limiting the scope of the invention.
Example 1:
the method for preparing the lithium battery graphite negative electrode material by using the lignin comprises the following steps:
1) 20 kg of pine wood particles (the water content of the pine wood particles is less than 8 percent, and the particle diameter of the pine wood particles is less than 25 mm), 20 kg of water, 60 kg of tetrahydrofuran and 600g of concentrated sulfuric acid are added into a reaction kettle and uniformly mixed (the mass concentration of the concentrated sulfuric acid is 98 percent). Stirring and heating the reaction kettle to 180 ℃ in a nitrogen atmosphere, reacting for 20 minutes, adding 1 kg of calcium hydroxide slurry with the concentration of 50% w/w to neutralize sulfuric acid in the solution after determining that cellulose, hemicellulose and lignin in pine wood particles are liquefied and hydrolyzed, and filtering to obtain 100 kg of reaction liquid;
2) mixing 100 kg of reaction liquid obtained in the step 1) with 250 kg of water, stirring uniformly, separating out solids, filtering, washing filter residues with 500 kg of water, and drying to obtain 10 kg of lignin;
3) mixing 10 kg of lignin obtained in the step 2) with 100 kg of diammonium hydrogen phosphate aqueous solution with the mass concentration of 10%, standing and stabilizing at the temperature of 60 ℃ for 4 hours, filtering, and drying filter residues to obtain 10 kg of stable lignin;
4) placing 10 kg of the stable lignin obtained in the step 3) into a rotary furnace, and calcining for 4 hours at 1400 ℃ under the protection of nitrogen to obtain 5 kg of calcined lignin;
5) and (3) placing 5 kg of calcined lignin obtained in the step 4) into a graphitization furnace, calcining for 12 hours at 2700 ℃ under the protection of argon, and naturally cooling to room temperature to obtain 3 kg of the lithium battery graphite cathode material.
The lignin obtained in step 2) of example 1 was subjected to a performance test: it has an aromaticity of 85% as determined by the ISO 21461 method, a sulfur content of 0.01% as determined by the GB/T2286 method and an ash content of 0.1% as determined by the GB/T2001 method.
In the prior art, whether a graphite negative electrode material of a lithium battery meets a standard or not is evaluated, and the following performance detection standards in 5 aspects are generally required to be met:
1 specific discharge capacity for the first time: the initial discharge specific capacity of the material is usually tested by GB/T2433s2019 standard, the initial discharge specific capacity of the high-performance natural graphite material is about 360mAh/g, the initial discharge specific capacity of petroleum coke in the artificial graphite is generally between 300 and 350mAh/g, and the initial discharge specific capacity of the lithium battery graphite cathode material cannot be too small.
2 first coulombic efficiency: the first coulombic efficiency of the graphite cathode material of the lithium battery is generally tested by adopting the GB/T2433and 2019 standard. In the process of first charging, lithium ions are inserted into the negative electrode material, when the battery discharges, the lithium ions inserted into the negative electrode material return to the positive electrode material, and because pores in the material are complicated and complicated, not all the lithium ions can be completely extracted, the method obtains the actually available capacity after the first charging, the higher the numerical value is, the higher the available volume of the negative electrode material is, and the first coulombic efficiency of petroleum coke is generally between 90 and 95 percent.
3 powder compacted density: the powder compaction density of the graphite cathode material of the lithium battery is generally tested by adopting the GB/T2433and 2019 standard. The higher the compacted density is, the higher the energy density of the lithium battery with the same volume is, and the compacted density of the petroleum coke lithium battery cathode material of the common artificial graphite is 1.0-1.4g/cm3。
4 degree of graphitization: the graphitization degree of the lithium battery graphite cathode material is generally tested by adopting the GB/T2433and 2019 standard. The higher the graphitization degree, the better the performance of the lithium battery negative electrode material. Generally, the graphitization degree of petroleum coke of the artificial graphite after graphitization is between 85% and 95%.
5, fixed carbon content: the fixed carbon content of the graphite cathode material of the lithium battery is generally tested by adopting the GB/T3521 standard. The fixed carbon content represents the content of carbon elements in the negative electrode material, and the higher the fixed carbon content is, the lower the contents of ash and volatile components in the material are, and the better the product performance is. The fixed carbon content of high performance petroleum coke is generally between 99.7% and 99.97%.
Example 1 the performance test data of the lithium battery graphite cathode material prepared by using lignin is shown in table 1, and the table 1 also lists the performance standard of petroleum common coke in artificial graphite under the national standard GB/T2433and 2019.
TABLE 1
As can be seen from Table 1, the lithium battery graphite cathode material prepared in example 1 of the present invention has quality performance equivalent to the quality performance parameter of petroleum coke in artificial graphite. The method for preparing the graphite cathode material of the lithium battery by using the lignin disclosed by the invention meets the use standard of the cathode material of the lithium battery. The method can develop and produce downstream graphite material products with high added value by using biomass as a raw material.
The statements in this specification merely set forth a list of implementations of the inventive concept and the scope of the present invention should not be construed as limited to the particular forms set forth in the examples.
Claims (6)
1. The application of the lignin in preparing the lithium battery graphite cathode material is characterized in that the preparation process of the lignin is as follows: adding 2-10 volume times of water into the hydrolyzed feed liquid, stirring, separating out solids, filtering, washing filter residues with clear water, and drying to obtain lignin;
the method for preparing the lithium battery graphite cathode material by taking lignin as a raw material comprises the following steps:
1) mixing lignin and a stabilizer solution according to a mass ratio of 1: 2-12, standing and stabilizing at 40-70 ℃ for 3-6 hours, filtering, and drying filter residues to obtain stable lignin;
2) placing the stabilized lignin obtained in the step 1) in a rotary kiln, and calcining for 2-4 hours at 1200-1500 ℃ in a nitrogen protective atmosphere to obtain calcined lignin;
3) placing the calcined lignin obtained in the step 2) in a graphitization furnace, calcining for 3-15 hours at 2500-2800 ℃ in an argon protective atmosphere, and naturally cooling to room temperature to obtain the lithium battery graphite cathode material.
2. The application of the lignin in preparing the graphite cathode material of the lithium battery according to claim 1, wherein the stabilizer solution is a diammonium hydrogen phosphate aqueous solution with the mass concentration of 10-20%.
3. The application of the lignin according to claim 1 in preparing a graphite negative electrode material of a lithium battery, wherein a reaction solution obtained after hydrolysis reaction of biomass in an acid solution is prepared according to the following processes:
s1: adding biomass particles into a reaction kettle, adding a water cosolvent in an anaerobic state, heating to 150-220 ℃ under stirring, adding Lewis acid, and performing hydrolysis reaction for 20-40 minutes to obtain a hydrolyzed biomass mixed solution;
s2: and (4) adding alkali into the biomass mixed liquid obtained in the step (S1) to neutralize and adjust the pH value to 4.5-8, cooling, and filtering to remove precipitates obtained by neutralization and ash in the biomass to obtain the reaction liquid.
4. The use of lignin according to claim 3 in the preparation of graphite negative electrode material for lithium battery, wherein the water content of biomass particles in step S1 is less than 8%, the particle size is less than 25mm, and the biomass is any one or more of straw, paper products, pine, grasses, rice hulls, bagasse, cotton, jute, flax, bamboo, sisal, abaca, straw, and corn cob.
5. The application of the lignin according to claim 3 in the preparation of a lithium battery graphite negative electrode material, wherein in the step S1, the mass ratio of the water cosolvent is 1: 1-1: 5 water and tetrahydrofuran.
6. The application of the lignin in preparing the graphite cathode material of the lithium battery according to claim 3, wherein in the step S1, the mass ratio of the biomass to the water cosolvent is 1: 2-7; the Lewis acid is at least one of sulfuric acid, hydrochloric acid and nitric acid, and the mass of the Lewis acid is 0.3-3% of that of the water cosolvent.
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| WO1998004009A1 (en) * | 1996-07-19 | 1998-01-29 | Motorola Inc. | High volumetric capacity electrodes and electrochemical cells using same |
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