Disclosure of Invention
The technical problems to be solved by the invention are as follows: aiming at the current SnO2The invention provides a preparation method of a lithium ion battery cathode material, which has the advantages that huge volume expansion can be generated in the charging and discharging processes, and further, particle pulverization and agglomeration are generated, so that the problems of low reversible capacity and poor cycle performance of the cathode material are caused.
In order to solve the technical problems, the invention adopts the following technical scheme:
a preparation method of a lithium ion battery negative electrode material comprises the following steps:
(1) uniformly mixing tetraethoxysilane, glycol and an ethanol solution according to the mass ratio of 1: 4-6: 5, performing ultrasonic oscillation, adding an additive accounting for 1-3% of the mass of tetraethoxysilane, stirring and mixing, and standing to obtain a basic mixed solution;
(2) taking 70-90 parts by weight of basic mixed liquid, 40-50 parts by weight of ammonia water, 4-6 parts by weight of bromohexadecyl pyridine, 3-7 parts by weight of modifier and 1-5 parts by weight of surfactant, putting the mixture into a reactor, and stirring and reacting the mixture under the protection of nitrogen at the temperature of 122-125 ℃ under the pressure of 1.3-1.5 MPa;
(3) after the reaction is finished, collecting a reaction mixture, uniformly mixing the reaction mixture, stannic chloride and water according to the mass ratio of 2: 4-6: 5: 4-7, adjusting the pH to 6.5-7.0, standing, performing microwave heating to 300-450 ℃, preserving heat, filtering, and collecting filter residues;
(4) and performing laser irradiation modification on the filter residue, washing, drying and crushing to obtain the lithium ion battery cathode material.
The additive in the step (1) is any one of barium sulfate and barium nitrate.
In the step (2), the modifier is n-octyl triethoxysilane and vinyl trimethoxysilane which are mixed according to the mass ratio of 4: 4-6.
And (3) in the step (2), the surfactant is any one of sodium dodecyl benzene sulfonate and sodium dodecyl sulfate.
The washing process in the step (4) is sequentially performed by using ethylene glycol, ethanol and water.
The laser irradiation modification in the step (4) is carried out under the conditions that a carbon dioxide laser is used, the power is 900-1000W, the scanning width is 3-5 mm, and the scanning speed is 0.9-1.1 m/min.
Compared with other methods, the method has the beneficial technical effects that:
according to the preparation method, ethyl orthosilicate, bromohexadecyl pyridine, a modifier and the like are used as raw materials to prepare the modified mesoporous silicon carrier, in the process, tin tetrachloride and graphene form a gel coated carrier under the action of ammonia water, the adsorption performance of the mesoporous carrier is improved under the modification of the modifier, tin elements are adsorbed inside the mesoporous carrier, the expansion performance of the carrier and tin oxide can be effectively inhibited by adding trace barium elements, the carrier loaded with tin is combined on the surface of the graphene through the modification of laser, a compact tin oxide layer is formed, the mesoporous carrier is protected outside, the expansion of tin oxide and the agglomeration of particles in the use process can be effectively avoided, and the reversible capacity and the cycle performance of a negative electrode material are effectively improved.
Detailed Description
The additive is selected from any one of barium sulfate and barium nitrate.
The modifier is selected from n-octyl triethoxysilane and vinyl trimethoxysilane which are mixed according to the mass ratio of 4: 4-6.
The surfactant is selected from one of sodium dodecyl benzene sulfonate and sodium dodecyl sulfate.
A preparation method of a lithium ion battery negative electrode material comprises the following steps:
(1) uniformly mixing tetraethoxysilane, glycol and an ethanol solution according to the mass ratio of 1: 4-6: 5, carrying out ultrasonic oscillation for 10min, adding an additive accounting for 1-3% of the mass of tetraethoxysilane, stirring and mixing, and standing for 10-15 h to obtain a basic mixed solution;
(2) taking 70-90 parts by weight of basic mixed liquid, 40-50 parts by weight of ammonia water, 4-6 parts by weight of bromohexadecyl pyridine, 3-7 parts by weight of modifier and 1-5 parts by weight of surfactant, putting the mixture into a reactor, and stirring and reacting for 6-8 hours at the temperature of 122-125 ℃ under the protection of nitrogen under the pressure of 1.3-1.5 MPa;
(3) after the reaction is finished, collecting a reaction mixture, uniformly mixing the reaction mixture, stannic chloride, water and graphene according to a mass ratio of 2: 4-6: 5: 4-7, adjusting the pH to 6.5-7.0, standing for 1-3 h, then carrying out microwave heating to 300-450 ℃, preserving heat for 70-90 min, filtering, and collecting filter residues;
(4) and (3) carrying out laser irradiation modification on the filter residue, setting conditions that a carbon dioxide laser is used, the power is 900-1000W, the scanning width is 3-5 mm, the scanning speed is 0.9-1.1 m/min, and sequentially washing with ethylene glycol, absolute ethyl alcohol and water, drying and crushing to obtain the lithium ion battery cathode material.
Example 1
The additive is selected to be barium nitrate.
The modifier is selected from n-octyl triethoxysilane and vinyltrimethoxysilane which are mixed according to the mass ratio of 4: 6.
The surfactant is selected from sodium dodecyl benzene sulfonate.
A preparation method of a lithium ion battery negative electrode material comprises the following steps:
(1) uniformly mixing tetraethoxysilane, glycol and an ethanol solution according to the mass ratio of 1:6:5, carrying out ultrasonic oscillation for 10min, adding an additive accounting for 3% of the mass of the tetraethoxysilane, stirring and mixing, and standing for 15h to obtain a basic mixed solution;
(2) according to the mass parts, 90 parts of basic mixed solution, 50 parts of ammonia water, 6 parts of bromohexadecyl pyridine, 7 parts of modifier and 5 parts of surfactant are put into a reactor and stirred and reacted for 8 hours at the temperature of 125 ℃ under the protection of nitrogen;
(3) after the reaction is finished, collecting a reaction mixture, uniformly mixing the reaction mixture, stannic chloride, water and graphene according to a mass ratio of 2:6:5:7, adjusting the pH to 7.0, standing for 3 hours, then carrying out microwave heating to 450 ℃, preserving heat for 90min, filtering, and collecting filter residues;
(4) and performing laser irradiation modification on the filter residue, setting the conditions that a carbon dioxide laser is used, the power is 1000W, the scanning width is 5mm, the scanning speed is 1.1m/min, and sequentially using ethylene glycol, absolute ethyl alcohol and water for washing, drying and crushing to obtain the lithium ion battery cathode material.
Example 2
The additive is selected to be barium sulfate.
The modifier is selected from n-octyl triethoxysilane and vinyltrimethoxysilane which are mixed according to the mass ratio of 4: 5.
The surfactant is selected from sodium lauryl sulfate.
A preparation method of a lithium ion battery negative electrode material comprises the following steps:
(1) uniformly mixing tetraethoxysilane, glycol and an ethanol solution according to the mass ratio of 1:5:5, carrying out ultrasonic oscillation for 10min, adding an additive accounting for 2% of the mass of the tetraethoxysilane, stirring and mixing, and standing for 13h to obtain a basic mixed solution;
(2) according to the mass parts, 80 parts of basic mixed liquid, 45 parts of ammonia water, 5 parts of bromohexadecyl pyridine, 5 parts of modifier and 3 parts of surfactant are put into a reactor and stirred and reacted for 7 hours at the temperature of 123 ℃ under the protection of nitrogen;
(3) after the reaction is finished, collecting a reaction mixture, uniformly mixing the reaction mixture, stannic chloride, water and graphene according to a mass ratio of 2:5:5:6, adjusting the pH to 7.0, standing for 2 hours, then carrying out microwave heating to 380 ℃, preserving the temperature for 80min, filtering, and collecting filter residues;
(4) and performing laser irradiation modification on the filter residue, setting the conditions that a carbon dioxide laser is used, the power is 950W, the scanning width is 4mm, the scanning speed is 1.0m/min, and sequentially using ethylene glycol, absolute ethyl alcohol and water for washing, drying and crushing to obtain the lithium ion battery cathode material.
Example 3
The additive is selected to be barium sulfate.
The modifier is selected from n-octyl triethoxysilane and vinyltrimethoxysilane which are mixed according to the mass ratio of 4: 4.
The surfactant is selected from sodium dodecyl benzene sulfonate.
A preparation method of a lithium ion battery negative electrode material comprises the following steps:
(1) uniformly mixing tetraethoxysilane, glycol and an ethanol solution according to the mass ratio of 1:4:5, carrying out ultrasonic oscillation for 10min, adding an additive accounting for 1% of the mass of the tetraethoxysilane, stirring and mixing, and standing for 10h to obtain a basic mixed solution;
(2) according to the mass parts, 70 parts of basic mixed liquid, 40 parts of ammonia water, 4 parts of bromohexadecyl pyridine, 3 parts of modifier and 1 part of surfactant are put into a reactor and stirred and reacted for 6 hours at the temperature of 122 ℃ under the protection of nitrogen;
(3) after the reaction is finished, collecting a reaction mixture, uniformly mixing the reaction mixture, stannic chloride, water and graphene according to a mass ratio of 2:4:5:4, adjusting the pH to 6.5, standing for 1h, then carrying out microwave heating to 300 ℃, preserving heat for 70min, filtering, and collecting filter residues;
(4) and performing laser irradiation modification on the filter residue, setting the conditions that a carbon dioxide laser is used, the power is 900W, the scanning width is 3mm, and the scanning speed is 0.9m/min, and sequentially washing with ethylene glycol, absolute ethyl alcohol and water, drying and crushing to obtain the lithium ion battery cathode material.
Comparative example
Commercially available SnO2Graphene lithium ion battery negative plate.
Preparation of negative plate
Adding N-methyl pyrrolidone (NMP) into the lithium ion battery negative electrode material prepared in the embodiment 1-3 and polyvinylidene fluoride (PVDF) according to the mass ratio of 8:1, mixing to prepare uniform slurry, uniformly coating the slurry on copper foil by using a coating method, drying, and punching into a circular electrode slice with the diameter of about 12mm to obtain the negative electrode slice.
Performance testing
The results of repeating charge and discharge at 200 mA/g for 100 times of the prepared negative electrode sheet and the negative electrode sheet of the comparative example are shown in table 1.
TABLE 1
Therefore, the cathode material prepared by the invention has better reversible capacity and cycle performance.